Wednesday, December 27, 2006


Afshordi et al. stack 193 X-ray emitting clusters to find a 9 sigma detection of the SZ effect in the WMAP 3-year data. They find that 32+/-10% of the baryons are not in the hot ICM.

Cattaneo & Treyssier perform detailed simulations of AGN feedback on cluster ICM and show that after an initial rapid accretion phase a stable solution is reached with a constant small accretion rate.

Hashimoto et al. analyze a sample of Chandra images of clusters using simple statistics to define morphology. They find that distorted and non-distorted clusters occupy different loci in the L-T plane but no correlation between morphology and luminosity or temperature.

Crowder & Cornish present their solution to the "cocktail party" problem of LISA analysis of Galactic binaries using a Blocked Annealing Metropolis-Hastings MCMC.

Riess et al. present new SNIa, 13 of which are at z>1, and conclude that the data are still consistent with w=-1 and rule out dw/dz>>1.

Borkin et al. use medical imaging technology for slicing 3D data cubes in an astronomical context as part of the Harvard AstroMed initiative.

Fusco-Femiano et al. argue that there really is a non-thermal excess from the Coma cluster.

Jonsson et al. calculate the effects of weak lensing on possible attempts to do cosmology useing GW detections of chirping black holes with EM counterparts (hence redshifts).

Nayakshin explains the variability of continuum and constancy of reflection components in AGN by arguing that disk coronal flares are likely to emit anisotropically.


McHardy et al. argue on the basis of X-ray variability and optical emission line widths that AGN are just scaled-up galactic binaries in terms of their black hole accretion process.

Schaefer constructs a Hubble diagram from 69 GRBs and argues that it provides an accuracy only a factor of 2 worse than the big SNIa surveys.

Boyarsky et al. note that improved limits on the sterile neutrino can be obtained using a wide-field but low effective area (ie no telescope) calorimeter.

Ravikumar et al. present new redshifts of objects in the CDFS (alias GOODS-South) and note that this field contains anomalous structures containing evolved, massive galaxies.

Barack & Cutler investigate how well LISA observations of EMRIs can test that spacetime around a rotating BH is the Kerr metric.

Wise et al. report on a deep Chandra observation of Hydra A which shows extensive cavities which correlate precisely with 330 MHz emission.

Belczynski et al. argue that the creation of stellar mass BH binaries are suppressed by mergers during the common envelope phase and so these are not likely to be a significant population for advanced LIGO.

Andersson et al. use their new Smoothed Particle Inference technique to derive temperature maps of three clusters observed using XMM.

Tuesday, December 26, 2006


Gogus et al. point out that supposing Compton scattering dilutes the NS rotation signature in LMXBs also predicts a hard tail from upscattering of NS surface soft photons and this is not seen.

In the first of a series of papers Young & Fryer look at the uncertainties in element yields from SN explosion models.

Lin & Mohr survey radio sources in 573 clusters using data from the NVSS and note that as many as 10% of clusters may have 150 GHz fluxes from AGN comparable to the SZ signal.

Kashlinsky et al. extend their P(D) analysis of Spitzer data to the GOODS dataset and find further evidence for extragalactic fluctuations. In another paper they also discuss the nature of the sources.

Finoguenov et al. report on cluster detections in the first 36 pointings of the XMM-COSMOS survey.

Hayashi et al. simulate the cores of galaxy-sized dark matter haloes and find that the ellipticity increases towards the center. This may explain the observed flattening of velocity profiles in LSB galaxies.

Hopman et al. estimate the expected LISA signal from GW bursts caused by stars in close orbits with the Galactic Center BH.

Jetha et al. study 15 groups with Chandra and find no significant differences in gas profiles between those with radio-loud and radio-quiet BCGs.

Begelman & Pringle consider accretion disks with toroidal magnetic fields and find they are thicker than standard disks for the same radius and accretion rate and have a higher color temperature.

kerrbb model

Jeff McClintock writes :

Some users of kerrbb have been freezing the inclination (par3), the mass(par4), and the distance (par6) and then allowing the normalization constant K to vary. This is not correct: with i, M and D fixed, the normalization should be frozen at K = 1. The current instructions for running kerrbb, which we provided to you, are not clear on this point. When it is convenient, please change the last line of the description of kerrbb to read something like the following:

K =normalization. Should be set to 1 if the inclination, mass and distance are frozen.

We have made this change in the v11 and v12 documentation.

Keywords: HEAsoft, xspec

Friday, December 22, 2006

extractor and lightcurve files

The lightcurve file output from extractor did not necessarily include an extension named GTI as required by the standard. Now modified to add such a GTI extension. If there are multiple CCDs and hence gti extensions then individual extensions are still written but a GTI extension is also written containing the merged gtis. v4.72.

Note that this also fixes a bug in xselect when using select intensity on XMM data - the problem was that the new select intensity perl script assumes the presence of an extension called GTI in the lightcurve.

Keywords : HEAsoft, xselect, extractor

Monday, December 18, 2006

onepar bug

The wftbmd.f file in the onepar routine for creating single parameter table models does not initialize the status variable. This can lead to a spurious error message and program exit.

Keywords: HEAsoft, xspec

Thursday, November 30, 2006

Simultaneous fitting of source and background

Caroline Kilbourne points out that the new multiple source capability of xspec provides a clearer way of simultaneously fitting the source and the background. Suppose we have a spectrum source.pi which includes our source and some background and another spectrum back.pi which just contains background. These files have responses source.rsp and back.rsp, respectively. We now read these in by

XSPEC12> data 1:1 source.pi 2:2 back.pi
XSPEC12> resp source.rsp back.rsp
XSPEC12> resp 2:1 source.rsp

Now we set up the model for the background as the default model

XSPEC12> model ....

and the model for source as the second model

XSPEC12> model 2:source ....

The default model now has linked parameters across the two datasets while the second model just contributes to the model for source.pi.

Randall Smith suggests it would be nice to be able to fit models to the background which is read in as a background file eg something like

XSPEC12> data source.pi
XSPEC12> back back.pi
XSPEC12> resp source.rsp
XSPEC12> model ....
XSPEC12> model back ....

Note that this would also require us to be able to associate a background response matrix with the background spectrum eg

XSPEC12> resp back back.rsp

Keywords: HEAsoft, xspec

xselect.mdb update for Suzaku

Switched the default WMAP from SKY to DETECTOR and removed the TIME-OBS and TIME-END from the catalog display since these keywords are no longer used in the event file.

Keywords: HEAsoft, xselect, Suzaku

Tuesday, November 28, 2006

setplot id produces garbage in v11

K.D. Kuntz reported that xspec v11 produces garbage plots when setplot id is used. This was due to a mismatch in string lengths which is fixed in v11.3.2aa.

Keywords: HEAsoft, xspec

Wednesday, November 22, 2006

extractor bug when event file has 1 event !

Phil Evans and Laurence Tyler report from the Leicester Swift team that extractor core dumps when extracting an event file from multiple inputs if the second file has only 1 event. They tracked the problem to a floating divide by zero due to an uninitialized variable in xclock called from w_events. I fixed this by removing the xclock call because it makes no sense in w_events because we don't know the total number of events which will be written. Fixed in v4.71.

Keywords: HEAsoft, xselect, Swift

Thursday, November 16, 2006

extractor and physical coordinates

Added support for ds9 region files in physical coordinates. This is in addition to the options already supported of image, fk4, or fk5 (with the last two either in degrees or hms). v4.70.

Keywords: HEAsoft, extractor

extractor bug when using TIME as a filename filter

Stephen Holland points out that when using the TIME column in a filename filter eg test.evt[TIME=1.2e8:1.3e8] the exposure and gtis are not set correctly. Most people don't do this and it is not used in xselect. This bug is fixed as v4.69.

Keywords: HEAsoft, extractor, xselect

Wednesday, November 08, 2006

subtle problem in xselect filter intensity

Phil Evans spotted a subtle problem using filter intensity. Extra time is rejected at the start and end of each gti of the lightcurve used as the basis of the intensity filtering. The reason is that the lightcurve assigns a time to the center of the bin and these times are used by maketime to create the filter gtis. We used prefr=postfr=0.5 in maketime so that if bin I does not satisfy the filter and bin I+1 does then the starting time of the gti is (t(I)+t(I+1) )/2, which is correct. However, if the first or last bin of an input gti satisfies the filter then maketime just uses t(I) leading to the loss of half a bin. I've corrected this by writing a perl script called by the filter intensity command which creates a new temporary lightcurve with extra bins before and after each gti (and with rate=0). This temporary lightcurve is used as the input for maketime and ensures that no time is lost. A test is to do a filter intensity with range 0.0-* then extract a new lightcurve. The result has exactly the same gti as the pre-filtered lightcurve.

Keywords: HEAsoft, xselect

faking XMM RGS spectra in xspec v11

Piero Ranelli reports that using the background file produced by the SAS tool rgsbkgmodel in xspec v11 fakeit produces errors. The cause was an array overflow in wrtfak.f because I'd not increased the size to allow for up to 7 columns in the output spectrum. This problem does not occur in v12. Fixed as 11.3.2z.

Keywords: HEAsoft, xspec

Tuesday, November 07, 2006

xspec v11 inibin and stwght fixes

Backed out the change to inibin which attempted to have the energy range warning write out once per fit at chatter level 10. A bug caused the message to be written every iteration and the basic idea has a flaw anyway. So now back to writing the message every iteration but at chatter level 15. Bug fix 11.3.2x.

For the weight command trapped the case of no datasets read in. Now writes a warning message and returns immediately. This fixes a bug that if the weight command was used before readinga dataset a then subsequent use of the weight command required an explicit dataset number to have any effect. Bug fix 11.3.2y.

Keywords: HEAsoft, xspec

Saturday, November 04, 2006

xspec tcl script to run multiple fakeits

A handy new script to run fakeit many times for a given input response, background and model then write the results to a FITS binary table. At the moment the script only works for one input file and just does a fit after each fakeit and stores the resulting parameters. It thus provides a way of testing for bias in the fit statistic. The next step is to allow testing for bias in the production of confidence regions.

Updated 9/16/06 with improved speed and error-checking.

Keywords: HEAsoft, xspec

Friday, November 03, 2006

extractor for events with differing WCS

Giacomo Vianello pointed out a confusion in using extractor (actually extract in xselect) when multiple event files with differing WCS are read. The extracted image has sky coordinates corrected to the same WCS however the extracted event file does not. This means that doing a straight extract image produces a sensible looking image but doing an extract events followed by an extract image produces multiple sources. I've checked in a fix (as v4.68) which corrects this and transforms sky coordinates to the same WCS when extracting events. This is at a slight cost in speed but only for the case when WCS differ.

Keywords: HEAsoft, xselect, extractor

Monday, October 30, 2006

PGPLOT background color

Since I never remember how to make sure the background color is white in PGPLOT and PLT plots here are two ways to do it.

1. setenv PGPLOT_BACKGROUND white

2. PLT> scr w
which is a quick alias for
PLT> scr 0 1 1 1
PLT> scr 1 0 0 0

Keywords: HEAsoft, PLT, PGPLOT

new xspec models

Added to the new models page Chris Done's model for partially ionized absorber with velocity shear and Laura Brenneman and Chris Reynold's model for the broad Fe K line from the disk around a rotating black hole.

Keywords: HEAsoft, xspec

Friday, October 27, 2006


Gott et al. compare the topology of large scale structure observed using the SDSS with cosmological simulations.

Jimenez et al. use SDSS spectra of 22000 early-type galaxies to study ages, metallicities and star formation histories. Large galaxies have older stars and chemical enrichment lasts 1-2 Gyr.

Burenin et al. present the results of their 400 sq deg ROSAT PSPC galaxy cluster survey including 266 optically identified clusters, groups, or individual galaxies.

Law et al. find no evidence to suggest that the morphologically irregular galaxies at z~2-3 are due to galaxy mergers.

Mathews et al. find that the large scatter in Lx/Lopt for elliptical galaxies can be attributed to variations in the dark halo mass.

Agol provides a comprehensive set of relations for the efficiency of finding extrasolar planets i coronagraphic surveys.

Lahav offers an astronomical view on astrostatistics.

Guainazzi & Bianchi present the results of XMM RGS observations of 69 obscured AGN which support the scenario that the soft excess is due to photoionization of circumnuclear gas.

Thursday, October 26, 2006

bug fix for diskpbb model

Ken Ebisawa supplied a fix to diskpbb.f. He notes that
  The bug was such that the old normalization was wrong in that it
was 0.75/p times smaller. The correct normalization is obtained
by multiplying 0.75/p to the normalization of the old code. Disk
radius is proportinal to the square root of the normalization, and p
can be as low as 0.5, so the correct inner radius may be up to
1.11 time greater than the radius obtained from the old code.
Luckily, this would not dramatically change the consequences of the
papers already published by old diskpbb code (Okajima et al.,
Vierdayanti et al., and what else?).

Keywords: HEAsoft, xspec

Tuesday, October 24, 2006

energy compression for rbnrmf

Added to rbnrmf the option to compress RMFs in energy bins either using a single compression factor or a series of factors read from an ascii file.

Keywords: HEAsoft

Friday, October 20, 2006

lorentz model documentation error

Mariano Mendez points out that in the xspec v11 documentation the second parameter is described as the line width (sigma). That should be FWHM. The v12 documentation is more ambiguous but also implies that the line width is sigma. Again, it should be FWHM.

Keywords: HEAsoft, xspec

Thursday, October 19, 2006

table model example code

Added twopar - an example program to make an additive table model with two interpolation parameters. Also fixed a couple of potential problems in the wftbmd routine and the onepar program.

Keywords: HEAsoft, xspec

Monday, October 16, 2006

filter time scc

Fixed a bug in the xselect "filter time scc" command which was reported by Phil Evans. In earlier versions of the program the numbers entered if a lightcurve had been extracted were relative to the offset SCC value written in the header of the plot. This behaviour was unintentionally changed in v2.4 to require the absolute SCC number to be entered. The old behaviour has now been restored by editing the routine filter_time_cursor in xsel_utils.f.

Update 10/26/06 : Evert Rol reported that using 'r' as the second option in a time interval gives an error. This would due to a parsing mistake in the str2sec routine.

Keywords: HEAsoft

flx2xsp and wtpha

Created a new version of wtpha - called wtpha3 - which optionally writes multiple spectra in typeII format. Then used this in an upgrade of flx2xsp which can read multiple spectra from the ascii file and write them to a single FITS spectral file. This new option is invoked using the nspec parameter.

Keywords: HEAsoft

Wednesday, October 04, 2006


Sahu et al. use HST observations of a Galactic bulge field to find transiting planets, 5 of which have periods < href="">Muchovej et al. report first results from the Sunyaev-Zel'dovich Array of measurements of 3 high redshift clusters. Measured cluster properties are consistent with those determined from X-ray observations.

Belsole et al. present results from Chandra & XMM observations of the environments of 19 radio galaxies at 0.5.

Brenneman & Reynolds use Fe-K line observations with XMM and a new model (kerrdisk) to constrain the black hole spin in MCG-6-30-15.

Ziaeepour & Rosen use the Chandra Multi-Wavelength public data to discuss statistical classification of X-ray sources.

Berti & Cardoso discuss how to distinguish massive BHs from boson stars using LISA observations.

Monday, October 02, 2006

Suzaku mdb change

Updated xselect.mdb because the lststr setting for Suzaku XIS was incorrect for the output from v1 processing. The make obscat command does not work without this change.

Also, updated my brief notes on using xselect for Suzaku analysis.

Keywords: Suzaku, HEAsoft, xselect

Monday, September 25, 2006


Ota et al. find no evidence using Suzaku data for bulk motions in the Centaurus cluster in contrast to the claim using Chandra data.

Weisskopf et al. place stringent upper limits on X-ray emission from a single, cool, magnetic WD. They also note a statistical methodology for detecting a source when there are very few counts in the source and background.

Schwope et al. conclude on the basis of deep XMM spectroscopy that one at least of the two absorption lines in the spectrum of the isolated NS RBS1223 must be of atomic origin because their flux ratio is not consistent with a cyclotron origin for both.

Balestra et al. combine the analysis of Chandra observations of 56 clusters to examine the Fe abundance change with redshift finding a decrease parametrized as (1+z)^-1.25.

Cen shows that if gas disk accretion onto a SMBH is only efficient for a surface density > 10g/cm^2 then the SMBH mass - bulge velocity dispersion relation results.

Kondratko et al. report the discovery of 5 more AGN with water masers.

Schmidt & Allen present Chandra observations of 34 massive, dynamically relaxed clusters and find that the NFW model provides an acceptable fit in ~80% of cases.

Jeffery et al. support the proposal that the SNIa 2003fg had a progenitor above the Chandrasekhar limit.

Bogdanovic et al. discuss possible EM signals from close binary SMBH.

Monday, September 18, 2006


Tegmark et al. present the cosmological results from the real-space power spectrum based on the SDSS luminous red galaxy survey. Baryon oscillations are clearly detected at a mean z=0.35.

Anderson et al. continue their work cross-correlating RASS sources with the SDSS to generate a large sample of X-ray emitting AGN.

Pratt et al. present temperature profiles from XMM observations of a representative sample of nearby clusters. Outside the core they find similar profiles which agree well with numerical simulations.

Hogan summarizes current ideas on gravitational wave tests for new physics.

Brewer et al. describe a Bayesian MCMC approach to extract stellar oscillation frequencies from light curves.

Elvis et al. describe an active-optics concept for making high resolution mirrors with low mass/unit area.

Poole et al. show the results of SPH simulations of mergers between idealised X-ray clusters. They reproduce the features observed in Chandra and XMM observations and note that neither of the compact cores of the merging clusters are disrupted.

Petric et al. put limits on extragalactic dust from the lack of a halo in a Chandra observation of a z=4.3 quasar.

Albrecht et al. is the report of the dark energy task force.

Wright describes a handy cosmology calculator for times and distances as a function of redshift.

Thursday, September 14, 2006

PGPLOT - new ps driver

There were a few problems in the HEAsoft 6 release stemming from the new PS driver we introduced. The QDP font command didn't work correctly, the grfont.dat file was switched from binary to ascii introducing conflicts if the user already had PGPLOT installed, and a new file was required also leading to potential conflicts. All these have been fixed in a patch available from the HEAsoft bugs page.

UPDATE: A couple more problems were spotted by Glenn Morris. Symbols didn't work correctly in sub and superscripts and several symbols did not plot. I fixed the sub and superscript problem and at the same time added the ability to deal with multiple levels of sub/superscripts. Some of the symbol problems were due to a typo. Others still remain because there is no equivalent in a PS font for some Hershey symbols. The most important one appears to be the Solar symbol. It may be necessary to handle this one as a special case by writing an "O" then backspacing and shifting vertically and writing a "."

Keywords: HEAsoft, pgplot


Hicks et al. report on Chandra and optical observations of the CNOC subsample of EMSS clusters and find excellent agreement between X-ray, dynamical and lensing mass estimates.

Iye et al. find a galaxy at z=6.96 with star formation at ~10 Msun/yr.

Babich & Loeb claim that Thomson scattering off electrons in the outflows from Lyman Break Galaxies could produce CMB fluctuations on arcminute scales comparable to the level of those produced during reionization.

Kramer et al. summarize the results of 2.5 years of observations of the binary pulsar J0737 - these already match the predictions of GR to 0.05% and in future years will supersede the accuracy of Solar System tests.

Ballantyne et al. calculate Spitzer AGN luminosity functions using models of the CXRB and Cloudy.

Han & Zhang compare the windowed FFT and Hilbert-Huang analysis methods for Poisson X-ray data and conclude that the windowed FFT is far superior.

Vierdayanti et al analyze XMM spectra of 4 ULX sources and conclude that they can be explained by super-critical accretion (and hence slim disks) onto stellar mass BHs.

Feldmann et al. present ZEBRA, a Bayesian photometric redshift estimation code.

Hajian et al. describes the Hamiltonian Monte Carlo method applied to cosmological parameter estimation and notes that it offers efficiency advantages over MCMC.

Croston et al. have developed a regularization procedure for deprojecting and PSF-correcting XMM observations of clusters.

Monday, September 11, 2006


Koyama et al. present Suzaku XIS observations of the Galactic Center region. Using the observed Fe and Ni emission lines they show that the plasma is collisional and in ionization equilibrium with an Fe abundance ~3.5 times Solar.

Gregory uses a Bayesian Kepler periodogram to find a second planet orbiting HD208487.

Nagai et al. analyze simulated Chandra observations of clusters and conclude that the ISM mass is estimated correctly to better than 6% while the total gravitating mass estimate is biassed low by 5-20% due bulk motion pressure support.

Raymond et al. argue from dynamical simulations that planetary systems with "Hot Jupiters" can harbour Earth-analogs in the habitable zone.

McCarthy et al. compare WMAP3 results with baryon fractions from cluster observations and conclude that Omega_m is probably 0.28-0.39, higher than the WMAP3 best-fit value.

Centrella summarizes recent advances in numerical relativity and the calculations of BH merger gravitational waveforms.

Arzner et al. discuss the efficacy of various statistical methods in spectral fitting and advocate unbinned maximum likelihood.

Angus et al. argue that the "bullet cluster" results comparing X-ray and lensing images can be explained by a combination of MOND and 2eV neutrinos.

Paczynski proposes a number of projects using small (~10-30 cm) telescopes to look for variable objects. He also proposes a small telescope at L1 to give warning of "killer asteroids".

Stroeer et al. discuss automated Bayesian inference for LISA data analysis.

Vignali et al. select type 2 quasars on the basis of [OIII] emission then observe them with Chandra - their results support the idea that type 2 quasars are heavily absorbed in the X-ray.

Thursday, September 07, 2006

gti extension names for Suzaku

It appears we have an inconsistency in that the standard name for a gti extension used for suzaku is GTI however xselect is currently set up for STDGTI hence is used cleaned event files from processing. Changed xselect.mdb to to use GTI.

Tested what happens if xselect is used on an input event file with a gti name different from that set in the xselect.mdb. Reading event files with the "wrong" name for the gti extension doesn't seem to be a problem however using "load obscat" then "choose" produces an error message. I need to change the code so these cases are dealt with the same way. Also, shouldn't using DSS keywords get round this issue ?

Update: Modified xsel_read.f and xsel_mission.f so that the read and choose commands will work correctly for either STDGTI or GTI. Note that using DSS keywords doesn't help at present - should xselect be modified to use them ?

Keywords: HEAsoft, xselect, Suzaku

Tuesday, August 01, 2006

bldg2 printers

To print from the Unix shell under Tiger the printer name needs to include the machine name eg duplex4@lhea4.

Keywords: system

Monday, July 31, 2006


Davis et al. describe the multiwavelength extended Groth strip survey with observations from radio to X-ray.

Graham & Driver derive a quadratic relation between BH mass and bulge concentration.

Li Ji et al. develop a non-equilibrium ionization model for stellar cluster winds.

Bridges et al. do a full-up Bayesian analysis of the 3-year WMAP and LSS data and conclude that the n=1 spectrum can be ruled out and that the form of the deviation from n=1 differs from a power-law.

Malbon et al. graft black hole growth onto their galaxy formation model based on LCDM and predict the number and sizes of BH mergers.

Friday, July 28, 2006

xspec11 error in tclout compinfo

Jeremy Sanders points out that the number of parameters in the model returned by tclout compinfo is one too few. Simple error in tclout.c which is patched as 11.3.2v.

Keywords: HEAsoft, xspec

Monday, July 24, 2006

xspec 11 memory allocation errors in fakeit and tclout

Jeremy Sanders provided some fixes to memory allocation of strings in fakeit.c and tclout.c. Some sizes were being set without including the null at the end. Bug fix 11.3.2u.

Keywords: HEAsoft, xspec

Friday, July 14, 2006


Bouwens & Illingworth look for z~7-8 galaxies in NICMOS data and find less candidates than expected implying rapid evolution in the most luminous galaxies.

Wednesday, July 12, 2006

fix to genrsp

Randall spotted that the new v2.0 genrsp was only creating half-gaussian responses. This was due to a stupid error in clcrsp.f. v2.01 should get into the HEAsoft 6.1 release.

Keywords: genrsp, HEAsoft


Diehl & Statler present results of analyzing Chandra observations of 54 normal ellipticals. They find little correlation between optical and X-ray emission and conclude that the X-ray emitting gas is generally out of equilibrium and does not retain information about the shape of the underlying potential.

Park et al. develop a Bayesian treatment of hardness ratios.

Wilman et al. present optical integrated field spectroscopy of the H-alpha luminous central galaxies in the four cooling flow clusters and find disturbed emission coincident with secondary galaxies.

Wickham et al. develop the use of reversible jump MCMC to study SMBH binary systems with LISA.

de Freitas Pacheco et al. estimate the capture rate of compact objects by SMBH.

Sanders presents a new technique for performing spatially-resolved spectroscopy by selecting regions based on surface-brightness contours of the smoothed image.

Loeb looks at thermal evaporation from clusters and notes this could lead to a loss of at least a tenth of the gas at the cluster virial temperature.

Schnittman et al. use relativistic MHD simulations of accretion onto a non-rotating BH to predict features of the high-frequency power spectrum.

Trimble et al. present their annual summary of the year in astrophysics.

Heinz et al. find using numerical simulations that radio source morphologies can be significantly changed by bulk flows in the cluster gas.

Beckmann et al. present the 20-40 keV AGN luminosity function based on Integral observations covering 25000 deg^2 and detecting 38 extragalactic objects.

Lauer et al. argue that for brightest cluster galaxies the BH mass correlation with bulge luminosity is more likely to be correct than that with bulge velocity dispersion.

Arun examines the differences in parameter estimation between 3.5PN and 2PN for LISA observations of BH mergers.

Babak et al. present "kludge" gravitational waveforms for compact objects inspiralling around massive black holes.


Dotti et al discuss the EM signals or binary BH mergers detectable by LISA.

Maschenko et al. show that random bulk gas motions in primordial galaxies act to flatten the central dark matter cusps and hence solve the discrepancy between the predicted sharp cusps and observed flattened distributions.

Juett et al. present absorption edge results for Ne and Fe using HETG observations of X-ray binaries. They measure the Fe depletion onto dust grains and the Ne ionization structure of the ISM.

Kewley et al. analyze 85224 emission-line galaxies from the SDSS and derive a classification scheme which cleanly separates star-forming galaxies, AGN-HII composites, Seyferts and LINERs.

Cornish & Porter used annealed MCMC to extract the parameters for a SMBH binary embedded in a simulated LISA datastream.

Fregeau et al. discuss the detection probabilities with LISA and LIGO for IMBH binary mergers.

Dai et al. stack RASS data for over 4000 clusters selected from the 2MASS catalog and conclude that the relationships between mass, X-ray temperature, and X-ray luminosity are consistent with those for X-ray selected clusters.

McClintock et al. place a lower limit on the dimensional spin parameter for the BH in GRS1915 of 0.98 by modelling the X-ray continuum.

Schurch & Done model the soft X-ray emission from AGN as a failed disk wind where material is blown off the inner regions of the disk and falls back down onto the outer regions.

Rephaeli et al. analyze > 500 ksec of RXTE data on A2163 and derive a model where ~25 of the 3-50 keV emission is from a non-thermal component.

Sun et al. present a survey of the X-ray coronae of galaxies in nearby clusters.

extractor on OSF

The HEAsoft 6.1 version of extractor fails under OSF with

exception system: exiting due to internal error: out of memory trying to allocate exception system resources

We have no explanation for this at present. It appears to happen before any extractor code is executed.

Keywords: HEAsoft, extractor, OSF

Tuesday, July 11, 2006

extractor on Intel Mac

Fixed a bug when writing the XRONOS window file which showed up on the Intel Mac although since it was a format statement error we should have run into it before. v4.67.

Keywords: HEAsoft, extractor

Monday, July 10, 2006

xselect.mdb for Suzaku

At Koji's suggestion changed mkf_def_expr to ae*.mkf, since all relevant parameters are now included in the mkf file, and mkf_rel_dir to ../../auxil to conform to the v1 processing output.

Keywords: HEAsoft, xselect, Suzaku

Friday, July 07, 2006

pgplot /gif and /ppm drivers

Created C implementations of the pgplot /gif and /ppm drivers. The fortran versions of these use %VAL so fail on some fortran compilers. Used f2c to create a candidate C version then did a fair amount of tidying up. Confirmed that the drivers work correctly under Tiger but they may need tweaking for other systems.

Update: Added C implementation of pgplot /wd driver. More careful testing showed up a few discrepancies between the output files from the Fortran and C versions. After fixing some bugs the /ppm and /wd drivers produced identical binary output files from the Fortran and C versions. The /gif drivers produced small differences however these output files appear to be time-dependent since both the Fortran and C implementations produce slightly different binary files in successive runs. This was because the CODE array was not completely initialized to zero (one dimension was looped from 0 to 4095 not 0 to 4097 as required).

Keywords : heasoft, pgplot

Tuesday, June 20, 2006

PostScript driver

Another couple of tweaks to the PS driver to fix bugs. The code included some instances of the
string "\\" which were assumed to be interpreted by the compiler as "\". This doesn't work on all compilers so replaced this with char(92). Also, the prolog was being written with two instances of "%% Orientation", one specifying Landscape and the other Portrait. This was confusing Illustrator on the Mac.

Keywords: HEAsoft, pgplot

Tuesday, June 06, 2006

more XIS contamination models

After prompting by Aya Kubota I've made a model xiscoabh for the HXD nominal pointing position and xispcoab with an additional parameter giving the off-axis angle. Both these use the expression for column-depth vs off-axis angle from Dotani-san's e-mail.

Keywords: Suzaku

max number of GTIs in extractor

Someone on the Japanese side of the Suzaku team ran into the limit of 40960 rows in a GTI file ! I've increased this to 100,000 but it would be good to remove this limit completely and go to dynamically-allocated memory.

Keywords: HEAsoft, extractor, xselect

Monday, June 05, 2006

rdrmf5 and variable length records

There were two cancelling bugs in rdrmf4 and rdrmf5. The code to find whether a column was variable length had an error so never returned true. However, the attempt to then read all the data for a variable length column in one go is incorrect use of cfitsio, which requires such columns to be read one row at a time. Fixed both these bugs. Note that some tools still call rdrmf4 - these should be updated.

Keywords: HEAsoft


Lazendic et al. present results from the analysis of a 70 ksec Chandra HETG observation of Cas A and describe the techniques used on such a large and complex target.

Loewenstein looks at heavy metal creation in field and cluster galaxies and concludes that star formation is >3 times as efficient in clusters as in the field, mitigating the overcooling problem.

Bogdanov et al. propose that the tail in the spectrum of rotation-powered millisecond pulsars is due to Comptonization of the thermal polar cap emission.

Benford models jets and magnetic bubbles to argue that magnetic structures can persist long after the jet has turned off and this explains the bubbles seen in the ICM.

Miller et al. show from X-ray observations of GRO J1655 that the absorbing wind must be driven by magnetic forces internal to the disk.

Blundell et al. determine the low-energy cutoff for the energy of relativistic particles accelerated in radio lobe hot spots.

Krivonos et al. analyze Integral observations of the Galactic Ridge and show that in spectrum and spatial distribution it is consistent with a population of accreting magnetic white dwarf binaries.

Saunders et al. discuss the optimal sampling strategy for searching for periodic signals.

Pizzolato and Soker argue that the R-T instability in radio bubbles in cooling flow clusters is stabilised by the deceleration of the interface in the initial expansion of the bubble increasing the expected lifetime.

Hogan detects the production of gravitational wave bursts by light cosmic strings.

Friday, June 02, 2006

fakeit in v12

Changes to support use of Gaussian statistics when simulating the model part of the source file. If there is a pre-existing dataset then its value of is_Poisson is used when faking. If there is no pre-existing dataset then Poisson statistics are used.

This is required for Swift BAT simulations but also should be useful for other instruments which have non-Poisson statistics.

Keywords: xspec, HEAsoft

Thursday, June 01, 2006

PGPLOT PS driver

Made considerable simplification to the GRPSSY routine in psdriv.f. This was very baroque and I was able to reduce the code length by a factor of three and generate cleaner PS. This also fixed a nasty bug in the plot sens command in xspec.

Keywords: HEAsoft, pgplot

Wednesday, May 31, 2006

xselect and filter col PI=...

Fixed the case that the user does a filter column on the spectrum column (PHA or PI). Before this was not working because I automatically add a filter between the minimum and maximum allowed values. The two sets of filters are ORed in extractor so the filter column has no effect. Removed the min to max filter if a filter column on the spectrum is present. There is a potential conflict if the user does both a filter pha and a filter column on the PI/PHA. In this case the filter pha is ignored.

It would be to good to support exclude ranges in extractor so that the user could specify eg filter column PI=!1600:1700 to get all channels except 1600-1700.

Keywords: HEAsoft, xselect

more on xselect and filter time UT

Fixed further problems in filter time UT. Wrote a new wrap-up routine str2sec which converts a string of comma-delimited time specifications into an array of double precision SCC times. This replaces large chunks of code in xsl_time_cursor and xsl_enter_filter and eliminates most of the problems. Also fixed xsl_choose so that if the user loads an obscat and does a choose instead of read'ing files then the mjdrefi/f and timesys internal globals are set.

Keywords: xselect, HEAsoft

Tuesday, May 30, 2006

xselect and XMM response generation

Modified the XMM EPIC response generation perl script so that it uses the badpixel data. This required a new perl script (and code in xselect to call it) which copies the appropriate BADPIX## and EXPOSU## extensions from the event file to the spectrum file. At present this requires that there only be one event file from which the spectrum was extracted. If there are multiple event files then the user is advised to do an "extract event" then save the spectrum.

Moved XSL_RSPSAV from xsel_mission.f to xsel_utils.f since it has no mission-dependent code. Note that I slightly changed the behaviour of XSL_GRPSAV in the event that something goes wrong in getting the grouping.

Keywords: HEAsoft, xselect, XMM

Wednesday, May 24, 2006

Gary Hinshaw: WMAP 3 year results

EUD colloquium by Gary Hinshaw, data lead on the WMAP mission. He summarized the science justification and history then launched into the the 3 year results. The gain calibration has been improved leading to slightly different results on the temperature power spectrum - particularly at the low l end - and of course the S/N is improved. The big new result is the polarization map which provides a much better measure of the optical depth to free electron scattering - this is significantly less than the best-fit from the 1-year results implying a later reionization epoch (400,000 years after inflation rather than 100,000 years). Since the optical depth is highly correlated with the power-spectrum index this result also enables a more precise measurement of the index which is now inconsistent with Harrison-Zel'dovich n=1 at 2 sigma. The best fit is around n=0.96 consistent with two of the most popular inflation models. In answer to my question Gary also noted that the octopole is now more consistent with LCDM. The quadrapole best fit is still low however examination of the complete likelihood function shows a tail to larger values such that there is a 1/10 probability of getting the observed result. Since precision is limited by cosmic variance (the quadrapole is the variance of 5 independent numbers) we can't do any better.

Laurie Leshin: First results from Stardust

Goddard Science Colloquium by Laurie Leshin (GSFC) on the preliminary (and as yet unpublished) results from Stardust. She explained why comets are interesting - they were formed far enough out in the proto-Solar nebula that they should be unprocessed material which are deflected into the inner system and hence available for study. Sample return offers the benefit that all the heavy equipment can be kept on the ground and instrument development continues after the mission is completed. Stardust successfully collected cometary dust in its aerogel and preliminary examination is underway. The most unexpected result so far is the discovery of a refractory grain which should not be present in the comet if it is unprocessed.
She finished up by describing SCIM, a Mars Scout proposal, for a sample return mission which dips into the Martian atmosphere during the dust storm season to collect particles then returns them to Earth.

Phil Kronberg: Intergalactic CRs and mag. fields

EUD seminar by Phil Kronberg (LANL & U.Toronto) on some of his recent work on intergalactic magnetic fields observed via Faraday rotation. He is using Arecibo & DRAO interferometer to do a low surface brightness, wide-angle survey for intergalactic emission. The first field of the Coma cluster and surroundings shows emission from the same extended region seen in the X-rays.

Monday, May 22, 2006

string justification in the PS driver

Fiddled around with a hack to GRLEN to deal with the difference in character widths of for PS and PGPLOT symbols. The width ratio varies between different characters so had to give separate numbers for different categories. I only included the most common cases (a-z, A-Z, ".", "(", ")", " ", "-") but that should be close enough for most use.

The proper way to do string justification would be encode it in the PS file (using stringwidth and some tricky manipulation) however to do this the FJUST variable would have to be passed down to the GRTEXT routine and I didn't want to change the signatures of standard PGPLOT calls.

Keywords: HEAsoft, PGPLOT

Friday, May 19, 2006

more on the PS driver

Improved handling of text for the PS driver. Now pass the text bounding box values in the RBUF array for the IFUNC=31 option. These are calculated in GRTEXT where the only special case required for PS drivers is not to call GRLIN0 to actually plot the lines. This is much simpler than the previous method of setting the color to the special value of -1.

Also moved the PS driver-specific code related to the PS_VERBOSE_TEXT environment variable (which is obsolete) from GRTEXT into PSDRIV and reformatted and renamed the subroutines in PSDRIV to conform better to PGPLOT standards.

Thursday, May 18, 2006

xspec 12 start-up script

Eliminated the xspec v12 start-up script so that we just need the executable. The XSPECROOT environment variable is not used anywhere. SPECTRAL is used by routines in Global.cxx and XSGlobal.cxx where it can be replaced by HEADAS. POW_LIBRARY is set in headas-init. TCLRL_LIBRARY is used in xspec.cxx but the information it contains is available in tclreadline.h so just include that. The PGPLOT variables can all be removed once we merge the versions of pgplot under the Xspec and tcltk trees. The difference is Ben's PS driver. This uses PGPLOT_DIR for the directory containing - at the moment this is in the bin directory but should be moved to lib. PGPLOT_FONT is the font file which is an ASCII file in the Xspec tree and a binary unformatted file in the tcltk tree.

Fixed Ben's PS driver so that it is no longer necessary to set PGPLOT_PS_BBOX to MAX to avoid the chance of text being lost outside the bounding box. The trick is to have GRTEXT perform all the operations used for other devices which divide text up into line segments but not actually draw any of the lines. This ensures that the bounding box is set correctly. The
text is then written to the PostScript output. Also changed the write text option from IFUNC=30 to 31 because 30 is used for scrolling a rectangle in the X-window driver. The functions in src/grpssy.f are properly part of the PS driver so appended them to the end of psdriv.f.

Note that writing text the way we do at the moment does not conform to the pgplot architecture since it requires an explicit test for a PS device type in the routine grtext, which ought to be device-independent. The correct way to handle this is to define a new driver attribute to specify whether text needs to be split into line segments or can be written directly by the driver. grtext would then query this attribute rather than check for a specific device type.

PGPLOT_PS_BBOX should be set to MAX for Ben's PS driver otherwise text may end up lost off the edge of the bounding box.

Note that Ben's PS driver pretty clearly subverts the way that PGPLOT works. In standard drivers the text is written by drawing lines. Since PS handles text internally Ben set up a device-dependent diversion in GRTEXT to pass the text to the driver (using IFUNC=30). One consequence of this is that the bounding box variables (BBXMIN etc) are not updated for the position of the text hence the need to set PGPLOT_PS_BBOX. This ought to be fixable.

Wednesday, May 17, 2006

Suzaku XIS bad channels

Modified xselect.mdb to set the QUALITY on XIS channels 1-81 and 3290-4095 so they are ignored when the xspec command "ignore bad" is used.

Keywords: HEAsoft, Suzaku, xselect

mkfbin and hkbin

Modified mkfbin/hkbin so that if an event lightcurve has been extracted then the mkf/hk parameters will be binned to match the event lightcurve and the RATE will be added to the mkfbin/hkbin output file. plot mkf/hk then enables the user to plot correlations between housekeeping parameters and the event rate. Much of the code for this change has been moved out of Fortran and into a perl program (xsl_mkf_or_hk_bin).

This required a change to extractor to save the threshold used to choose whether to write out a lightcurve bin (ie minimum value of FRACEXP). This is extractor v4.65.

Added filter mkf and filter hk options as aliases for select mkf and select hk. Added save mkfbin and save hkbin options.

Set the xselect version number to 2.4 for the next HEAsoft release.

Keywords: HEAsoft, xselect, extractor

Tuesday, May 09, 2006

filter time ut in xselect

Scott Porter pointed out that the filter time ut command didn't work in xselect. This was due to errors in parsing the input and in converting UT to MJD. The manual doesn't state the format required for time - it is the standard used in FITS files ie yyyy-mm-ddThh-mm-ss.sss.

Keywords : xselect, HEAsoft

Thursday, May 04, 2006

IoA models in next v12 release

Added Andy & Roderick's models kdblur, kdblur2, rdblur, and laor2 to v12 as standard models for the next release.

Keywords: HEAsoft, xspec

Wednesday, May 03, 2006


Sutton & Wandelt present a Bayesian approach to optimal image reconstruction in radio interferometry. They use Gibbs sampling an incorporate an Occam factor.

Seljak et al. combine Ly alpha forest power spectrum results with 3-year WMAP, SN, and galaxy clustering data to constrain cosmological parameters finding the simple 6 parameter model is preferred with no running of the spectral index.

Belanger et al. claim a detection of a 22.2 min quasi-periodic modulation in the X-ray flux during the 2004 Aug 31 Sag A* flare. If this transient event was at the marginally stable orbit this implies an angular momentum parameter of 0.22.

Zucker et al. find a new Milky Way dwarf satellite galaxy at a distance of ~220 kpc using the SDSS data release 5. This discovery suggests other such objects are to be found. The same group report another dwarf galaxy.

Eisenstein et al. argue that the baryon acoustic peak can be reconstructed to correct for non-linear degradation providing significant improvements in determining the distance scale from galaxy surveys.

Bryans et al. present collisional ionization equilibrium calculations using state-of-the-art calculations from DR and RR rates.

Lawrence et al. describe the UKIRT Infrared Deep Sky Survey, a 7-year survey begun in May 05.

Begelman et al. suggest that SS433 is a ULX observed from the side with the radiative output collimated by a massive outflow from the disk at a distance of ~10% of the disk edge.

Sanders & Fabian construct a model for cluster X-ray emission including resonance scattering for several thousand lines. They find that including resonance scattering does not account for the observed dip in the central abundance however allowing for absorbing material within the inner 40 kpc of NGC4696 significantly improves the quality of the fits to the Centaurus cluster.

Forman et al. present the first results from the Chandra 500 ksec observation of M87.

Parkinson et al. apply Bayesian model selection theory to the 3-year WMAP data using the CosmoNest code and find weak evidence for a perturbation slope != 1.

Reiprich compares the 3-year WMAP results with those from the HIFLUGCS galaxy cluster sample and concludes that the new results are in much better agreement than the 1-year WMAP results.

Lieu: Soft X-ray cluster excess and SZ effect

EUD seminar by Richard Lieu from U. Alabama in Huntsville. The first half of the talk was a summary of soft X-ray observations of clusters. There are currently no confirmed observations of redshifted OVII so no definite evidence for WHIM in emission. The soft excess in the outer parts of clusters may still be thermal due to low S/N however that in the brighter regions must be non-thermal - possibly due to relativistic electrons accelerated in shocks or perhaps more exotic sources such as neutralino decay. The second and newer work was looking at WMAP data to measure the SZ effect from a sample of 30 bright, nearby clusters. The results are mixed - some clusters are clearly detected at the expected level (Coma), some are ambiguous, and some appear not to be detected at the level predicted by the X-ray data. Summing all 30 clusters and comparing with sets of randomly selected fields finds a net signal consistent with background (driven by the ~1 degree first peak in the power-spectrum). This is difficult to understand but implies some fraction of clusters do not show an SZ signal of the strength expected. Gary Hinshaw of the WMAP team confirmed that they also detect an SZ effect from Coma and that the noise level in Richard's plots is correct.

Keywords: Clusters, WMAP, SZ

Thursday, April 27, 2006

diskpbb and nsatmos added to v12

Added diskpbb and nsatmos to v12 for the new release. Note that nsatmos requires an ascii data file which was added to Xspec/src/spectral/modelIonData.

Keywords: HEAsoft, xspec

Wednesday, April 26, 2006

Natarajan: Weak Lensing

UMCP astronomy colloquium by Priya Natarajan from Yale. She summarized the effects of gravitational lensing and described her work deriving the poperties of subhaloes in clusters. She fits a smooth cluster distribution then a subhalo at the position of every cluster galaxy. 10-15% of the mass of the cluster is in the subhaloes which are individually more extended than the visible light of the galaxy. She essentially does a two-parameter fit for the subhalo properties assuming that all subhaloes in the cluster have similar properties. Recent extension of this work which is in press finds evidence for tidal truncation with smaller haloes in the center of the cluster. Finally she talked about prospects for investigating dark energy by comparing the lensing of background objects of different known redshifts. In this case the details of the lens drop out and the distance ratios to the background objects can be determined and hence the cosmology.

Keywords: clusters, lensing

Using Hera in xselect

Modified the xsl_xmm_epic_makeresp perl script so that when saving spectra in xselect and requesting a response matrix then Hera is used if SAS is not available on the local machine. I will make a similar modification to xsl_chandra_acis_makeresp when the appropriate updates are made to Hera to support it.

Keywords: xselect, HEAsoft, Hera, XMM

Tuesday, April 25, 2006

Lawrence Principe: Alchemy

Science colloquium by Larry Principe from JHU - professor in both chemistry and history of science departments. His principal argument is that alchemy is the legitimate forerunner to chemistry and alchemists have received an unfairly bad press. Many alchemists were extremely careful, observant, and dedicated experimenters. He showed pages from one alchemists lab notebook which looked similar to modern lab notebooks in the way that hypotheses were developed and tested by careful experiments. The idea of changing base metals to gold was based on a theory that all metals were composed of different amounts of philosophical mercury and philosophical sulphur. Study of alchemy is made difficult by the practice of alchemists encoding their public utterances. Fortunately, there are some private letters and notes that provide clues to the codes used. Part of Principe's research has been to decipher formulae for turning base metals into gold and then reproduce the experiments to find out what the alchemists were actually doing. He provided a recent example where the experiment produced a striking dendritic fractal structure looking very like a tree. Principe surmises that this explains the presence of trees in allegorical alchemical illustrations.

Monday, April 24, 2006


Suebsuwong et al. discuss the effects of light bending on the reflection spectrum from disks around black holes.

Jaffe et al. explore methods for fitting templates to CMB data.

Bock et al. is the final report of a DoE/NSF/NASA task force on the future of CMB measurements providing a roadmap for precision polarization measurements.

Stanek et al. observe that star formation occurs in galaxies with low O abundances and that long GRBs appear to correlate with star formation implying that the Milky Way is unlikely to have hosted a long GRB in the last few billion years.

LaRoque et al combine Chandra X-ray and OVRO/BIMA SZ measurements of 38 massive clusters. They find consistency with an isothermal model outside the cluster core and determine the gas mass fraction within r2500. Assuming this is constant with redshift the results are consistent with the standard LCDM cosmology.

Rodriguez et al. report the detection using VLBA of a SMBH binary with a separation of only 7.3 pc.

Loeb proposes searching for evidence of planets in nearby dwarf galaxies. Since these galaxies were formed at z~10 this would argue that planets can form when the Universe was 10^3 times as dense which would contradict the anthropic argument that a low cosmological constant is required for planet formation.

Brown et al. use HST to measure the size of UB313 and find it 5% larger than Pluto. The V band albedo is 86%.

Mahajan et al. point out that if the cosmological constant is surmised to be due the zero-point energy with a suitable ultraviolet cut-off scale to get the correct value then this is testable using observations of the Casimir effect. The constraint from observation requires a zero-point value 10^12 times larger than required for the cosmological constant.

Wilson et al. discuss their plan to use Spitzer surveys to find clusters in the 1 < z < 2 'desert'.

Thursday, April 20, 2006

PIE and PANDA regions in extractor

Modifications to extractor region code. For PIE region fixed incorrect definition of the angle so now consistent with ds9 and other regions and fixed error that threw out all events with angle > 180 degrees. Added support for PANDA region but only for the case of one sector and one annulus. For regions in WCS coordinates correct for any CROTA in use for the input event file.
(extractor v4.64.)

Keywords : extractor, xselect, HEAsoft

Wednesday, April 19, 2006

Mark Krumholz: Turbulence, Feedback, and Slow Star Formation

UMCP astronomy colloquium by Mark Krumholz, a postdoc at Princeton after doing his PhD at Berkeley. The major mystery of star formation is why it is so slow - the SFR is 100 times smaller than predicted based on free fall times. Krumholz & McKee have developed a theory where turbulence holds up star formation and the turbulence itself is produced by star formation. He showed that a fairly simple physical theory reproduces the observation results. The remaining problems are taking into account magnetic fields and explaining the 100 km/s turbulence seen in starbursts.

Keywords : star formation

xronos window output from extractor

Fixed a bug that caused incorrect time ranges in the xronos window output (created for instance by extr curve in xselect). This was reported by Gulab Dewangan at CMU. There is still an unresolved issue if the selected region overlaps multiple chips with separate GTIs. The xronos output file contains the GTI for the final chip (in numerical order). This fix is extractor v4.63.

Keywords: xselect, extractor, HEAsoft

Tuesday, April 18, 2006

Don Lamb: Short GRBs

EUD seminar by Don Lamb. He summarized the story from last year on short GRBs then talked extensively about a HETE burst that appears short but has a photometric redshift of 1.5 (if heavily reddened) or 4.6. He suggested that there are problems with a classification scheme based on spectral hardness since results appear not to be consistent between different missions. The T90 classification also has issues because it is measured in the observed frame. If long GRBs are cosmological then the rest frame durations are much shorter (by 1+z) so the distinction between short and long is eroded. Finally he noted that the presence of a spectral lag is a good classifier of a long GRB but there are some short bursts with negligible lag but large error bars implying they are not highly structured (so lag cannot be well-measured) so these might actually be similar to long bursts.

Keywords: GRB

Monday, April 17, 2006


Hudson et al. analyze Chandra observations of the double jet radio source 3C 75 at the core of Abell 400 and conclude that the two AGN are a bound system from a previous merger.

Rigby et al. consider why half of X-ray selected AGN are optically dull and conclude that extranuclear dust in the host galaxy plays an important role.

Stewart describes a procedure for matched filter detection of point sources in XMM images.

Ettori & Fabian argue that He sedimentation timescales in clusters were lower in the past leading to supersolar He abundances in the cores. This has the effect of reducing the measured metal abundances in these regions.

Wilson et al. use Chandra observations to investigate the bright limbs of the cavities in Cygnus A finding a weak shock and suggesting that the jet power is going into heating the ICM.

Barkhouse et al. present a survey for X-ray detected clusters in 130 archival Chandra pointings that are part of CHAMP.

Sandage et al. summarize their 15 year program to calibrate the SN Ia Hubble diagram using HST observations of Cepheids in nearby galaxies. They derive H0 = 62.3 +/- 1.5 (stat) +/- 5.0 (syst).

Kaaret et al find a 62 +/- 2.5 day period in the X-rays from the ULX source in M82.

Egami et al. describe Spitzer observations of BCGs and note an overall trend that clusters with shorter cooling times harbor more IR luminous BCGs.

Wednesday, April 12, 2006


Kravtsov et al. use mock Chandra images of cluster simulations to compare X-ray estimators for the total mass and show that the new estimator Yx is remarkably good.

Werner et al. look at very hot AGB stars which are thought to have consumed their H shells exposing nucleosynthesis products.

Ascasibar & Markevitch use simulations of cluster mergers to show that cold fronts are caused by the sloshing of the cool gas in the central gravitational potential well.

Wednesday, April 05, 2006

warning messages from znibin and inibin

Both inibin and znibin (in the NEI code cont.f) generate a warning if the response energies extend beyond the available model data. Ensured that these warning messages are written out once not every iteration. This will be in next v11 and v12 releases.

Keywords: xspec, heasoft

Friday, March 31, 2006


Kunz et al. introduce Bayesian complexity to assess how many effective parameters a data set can support.

Rasia et al. use five simulated galaxy clusters to investigate systematics in the determination of the total mass using X-ray observations.

Martini et al. survey 8 low-z clusters of galaxies for X-ray AGN and conclude that cluster galaxies host an AGN with a much higher frequency than supposed from optical observations.

Davis & Hubeny describe their relativistic, non-LTE atmosphere models for accretion disks in BH binaries.

Bregman & Lloyd-Davies conclude that the soft-excesses seen in clusters using XMM are not associated with the clusters but with Galactic features.

Allen et al. demonstrate a correlation between the Bondi accretion rate and the AGN jet power using Chandra data on 9 nearby ellipticals.

Wednesday, March 29, 2006


Baker et al. present the gravitational waveforms from the final inspiral and merger of two BHs.

Simpson & Bridle consider the redshift sensitivity of various dark energy surveys.

Davis et al. fit disk-dominated black hole binary X-ray spectra with a number of different models and conclude that BHSPEC works best.

Holder demonstrates that nearly exact likelihood functions can be written down for galaxy cluster surveys.
Bregman et al. present FUSE OVI observations of three cooling flow clusters and find evidence for modest cooling flows down to temperatures of 10^5.5 K.

Begelman et al. describe a mechanism for generating massive black holes directly in the nuclei of protogalaxies without the requirement for a seed stellar mass BH.

Voigt & Fabian use Chandra observations of 12 clusters to determine the core mass profile and in 4 cases find flatter profiles than predicted by CDM. They interpret this as an underestimation of the mass in the center and suggest reasons for this to happen.

Piffaretti & Kaastra apply the effervescent heating model to XMM observations of 16 nearby clusters and find that it works in half the cases.

Tuesday, March 28, 2006

xspec 11 poisson data warning

The warning message written by stat cstat if the data are non-Poisson can be generated even with Poisson data if there are large numbers of counts/bin. This has been fixed by being more careful about numerical accuracy. Bug 11.3.2t.

Keywords: xspec, heasoft


Williams et al. accumulate all the XMM calibration observations of Mkn 421 but fail to detect the absorption features seen using the Chandra LETG. However, their limits are consistent - the RGS being less sensitive due to the large number of bad detector columns, lower resolution, and fixed-pattern noise.

Linde et al. review eternal inflation and the multiverse.

Rines & Diaferio match X-ray cluster catalogs and the SDSS to examine infall patterns around 72 clusters. They demonstrate the reliability of the caustic technique for halo mass profiles.

Sereno et al. compare X-ray and SZ data for 25 clusters and estimate oblateness or prolateness. They find an excess of clusters aligned with the line of sight.

Tozzi introduces methods for determining cosmological parameters from X-ray observations of clusters.

Skinner considers the reasons for and against the use of Fresnel lens for focusing gamma- and high energy x-rays.

Nandra considers the emission sites of the narrow Fe K line cores and concludes that they are likely a mix of the inner edge of the torus and broadened emission from the accretion disk.

Garcia derives a simple approximation to the Voigt profile for use in studies of H absorption lines.

Tozzi et al. perform an X-ray spectral analysis of 321 sources in the CDFS.

Finn et al. describe the Testbed for LISA Analysis (TLA) project.

Best et al. look at radio-loud AGN heating as a regulator controlling the rate of growth of galaxies.


chkrmf was only checking for a MATRIX extension, not the also allowed SPECRESP MATRIX. Fixed this. Also, it was checking for required keywords in every extension - limited this to only the EBOUNDS and (SPECRESP) MATRIX extensions.

Keywords: chkrmf, heasoft

Friday, March 24, 2006


Trapped a possible write past end of string in xinfix which occurs if the new text input by the user is longer than the input string for the routine. I think this is what caused the xspec v11 crash under Scientific Linux 4.2 reported by Glenn Morris.

Notice that there is a more general problem here with v11 in that the string containing the command input by the user which is passed down to the xspec subroutines appears to have the
length of the command string. So, any replacement prompted from the user for part of this string has to be shorter than the original or problems will occur.

Note also that I need to remember that xspec gets the xparse routines from libxantcl not libxanlib - I wasted several hours trying to work out why changes placed in libxanlib weren't showing up when running xspec.

Keywords: xspec, heasoft


The model function routine xspwab.f used a real as a loop variable which produces an error using gfortran/g95 compilers since it is not part of the standard. Fixed this in both the v11 and v12 trees.

Keywords: xspec, heasoft

Thursday, March 23, 2006

xspec 11 floating overflow in ratio plots

Ryan Porter ran into a problem when doing "data ratio" plots which turned out to be a lack of protection against floating overflows when evaluating the ratio. This is fixed in 11.3.2s.

Keywords : xspec, heasoft

Thursday, February 23, 2006


Humphrey et al. present Chandra results on 7 elliptical galaxies and find the data well fit by a model consisting of an NFW dark matter profile and a baryonic component following the optical light.

Ebeling et al. describe the ASMOOTH algorithm for adaptive smoothing to a constant S/N ratio.

Tozzi et al. summarize recent results from spectral analysis of sources in the CDFS.

Suyu et al. use Bayesian analysis to determine the optimal regularisation for source inversion in gravitational lensing.

Middleton et al. attempt to determine the spin of the BH in micro-quasar GRS1915+105 and conclude that jet production is likely powered by gravity not spin.

Brighenti & Mathews describe 2D gasdynamical models of jets in clusters and show that they can suppress the cooling and produce cluster temperature profiles similar to those observed.

Scarpa et al. look at the outskirts of globular clusters to see whether velocity dispersion falls off in Keplerian fashion. They find a flattening consistent with MOND or requiring DM which has not been suspected in these systems.

Wednesday, February 22, 2006

plot mkf fix

The plot mkf command in xselect fails under Linux due to a string overwrite in xsel_ftools.f. The problem was a buffer array with fixed size in a subroutine. The size of the buffer has been increased and a warning added if the new size is too small.

Keywords: xselect, heasoft

Saturday, February 11, 2006

filter time file in xselect

The filter time file command assumes that the extension with the START and STOP times is the first extension in the file. Now generalized this so that it looks for the GTI extension.

UPDATE: Should have also looked for an STDGTI extension since this is written by maketime. Now fixed.

Keywords: xselect, heasoft

Tuesday, January 31, 2006

extractor fix for Swift UVOT lightcurves

Lightcurves from Swift UVOT event files could have TSTART=0 after time filtering. This is fixed in v4.62.

Keywords: HEAsoft, xselect, extractor

Wednesday, January 04, 2006


Dupke & Bregman confirm their ASCA SIS Centaurus cluster velocity measurements using Chandra ACIS. They measure a velocity difference of 2.4 +/- 1 x 1e3 km/s.

Diehl & Statler present a technique for binning sparse X-ray imaging data based on weighted Voronoi tesselation which does not introduce the artefacts seen using csmooth. Open source code is available.

Bellazini et al. describe their integrated Gas Pixel Detector for X-ray polarimetry.

Rozanska et al. present warm absorber models for AGN from clouds under constant total (gas + radiation) pressure.

Brand et al. present results from the XBootes Chandra 9.3 sq deg shallow survey with deep optical follow-up. They find 47 sources that are blank-field down to R~25.5.

Bonamente et al. combine Chandra and OVRO data on 39 clusters to determine their distances using the SZ effect. They find H_0 = 77 with statistical errors of ~5 and systematic errors of ~10.

Hickox & Markevitch analyze the diffuse emission in the CDFN and CDFS and find that 79+/-8% of the 2-8 keV background has been resolved.

Peterson & Fabian review the X-ray spectroscopy of clusters of galaxies.

Daly & Djorgovski extend their model-independent approach to investigating dark energy.

Savage & Oliver present Bayesian source extraction methods.

Ford discusses efficient MCMC methods for analyzing the orbits of extrasolar planets including choice of the candidate transition probability function.

Rothman & Boughn consider whether it is possible to detect a single graviton and conclude that the answer is no when taking into account realistic physical conditions.

Tuesday, January 03, 2006

addrmf and XIS rmf

Using addrmf on the x* XIS response files causes an error message about a failure to close the first RMF. This occurs because these files have no EXTNAME keyword for the EBOUNDS extension. The error message is misleading and unnecessary so is fixed in addrmf version 1.20.

Keywords: HEAsoft, Suzaku