Monday, October 31, 2005


Li-Xin Li & Paczynski present a new procedure for smoothing GRB lightcurves and calculating the variability. This leads to a very tight correlation between variability and peak luminosity.

Muanwong et al. use hydro simulations to investigate the evolution of X-ray cluster scaling relations under different mechanisms to increasing the entropy. They find indications that early, widespread pre-heating is favoured.

Dotti et al. study the inspiral of binary black holes inside a massive circum-nuclear disk.

Markwardt et al. present the first BAT serendipitous source catalog. The final catalog is expected to contain > 200 AGN and reach a limiting flux of 1e-11 in the 14-195 keV band.

Brewer & Lewis use Bayesian Inference and MCMC simulations on the strong gravitational lens problem.

Regimbau & Pacheco estimate the gravitational background from magnetars and note that it could mask a contribution from the early Universe.

Thursday, October 27, 2005


Dewangan et al. report the detection of a low frequency break and a QPO in the ULX M82 X-1. This is characteristic of an XRB in a high or intermediate state. The BH mass is estimated at 50-260 Solar masses.

Peterson et al. take a sample of nearby well-studied AGN and artificially redshift them to z=0.3 then consider what would be seen in a Chandra survey. They argue that these objects look like the "normal" and "optically-bright X-ray-faint" galaxy populations suggesting that these objects may contribute to the hard X-ray background.


Cappi et al. present the results of an XMM survey of the nearest 27 Seyfert galaxies. The results are broadly in agreement with unification models with Sy 2 absorption columns ranging from 1e20 to 1e25 cm^-2.

Zhao et al. apply Bekenstein's relativistic version of MOND to gravitationa lens observations. They find a range of acceleration scales are required in violation of the assumption that this is a universal constant.

Lu & Love present a method for diverting an Earth-threatening asteroid using a spacecraft that hovers near the object. This eliminates the anchoring and rotation problems of a spacecraft pushing on the asteroid.

Diehl & Statler analyze archival Chandra observations of 30 early-type galaxies and find a relation between the X-ray temperature, half-light radius, and mean surface brightness. The width of this fundamental plane (0.07dex) is nearly identical to that of the stellar (optical) fundamental plane.

Atoyan et al. argue that HESS J1303-631, a bright, extended TeV source invisible at other wavelengths is the remnant of a long gamma-ray burst.

Stroeer et al. discuss what can be learned from LISA detections of interacting double WD binaries.

Seward et al. find no evidence for a thermal shell around the Crab Nebula from Chandra observations. The background consists of a dust scattering shell and mirror scattering.
The shell has L_X < 1e34 erg/s.

Watson et al. present the Swift X-ray spectrum and lightcurve of the z=6.29 GRB. In the first few minutes of the burst the apparent luminosity was 1e5-1e6 times that of the brightest high-z quasars.

Sunday, October 23, 2005

xselect bug causing deletion of event files !

There is a bug in xselect which causes an event file to be deleted when running a make obscat for a mission with > 8 instrument types. This is triggered for the Suzaku HXD. I've fixed this by increasing the allowed number of types to 20 and putting in a trap to catch any future case of more than this. Also added DETNAM to the HXD displayed values so that the user can see which files in the catalog are PIN and which GSO.

Keywords: xselect, Suzaku

Saturday, October 22, 2005

CHANNEL column in type II files

At the request of the GLAST GBM folks removed the requirement for a CHANNEL column in type II spectral files. Having the CHANNEL column vector in every row is inefficient when there are many rows and the information is not required as long as data from all spectral channels are included in the COUNTS or RATE vector. Available as v11.3.2p and also shortly in v12. Need to update the standard memo appropriately.

Keywords: HEAsoft, xspec, GLAST

Wednesday, October 19, 2005

bug in extractor when combining 3x3 and 5x5 XIS files

Aya Bamba reported an obscure bug when running extract event in xselect. If both 3x3 and 5x5 event files are in use and the 5x5 is first then the resulting event file loses the events from the 3x3 file. Reproducing her problem showed that the events from the 3x3 file were in the output file but their TIME column had zero values. This was due to a bug in extractor which occurred if the first file had fewer columns than the second - the values from the extra columns would be lost even if these columns were matched in name with those in the first file ie if the differences between the files consisted of some additional columns added in the middle of the row. This
particular case has probably never arisen before. Fixed as extractor v4.59.

Keywords: HEAsoft, xselect, extractor, Suzaku

Thursday, October 13, 2005

extractor and region files

Extractor seg faults when fed a region file with a comment marker (#) included after a region descriptor. This can happen if a color is specified for the region using ds9.

Keywords: heasoft, extractor

Monday, October 10, 2005

grppha and grouping=0

Fixed grppha so that individual bad channels have grouping=1 not grouping=0. This conforms with the standard and ensures that xspec v12 doesn't issue a warning. This should not change any other behaviour.

Keywords: HEAsoft

Tuesday, October 04, 2005

xselect/extractor updates

A couple of minor updates. In extractor trapped the case of the grade column having no TLMIN/MAX. Previously this generated an obscure error when running. Now arbitrarily assumes that grade varies between 0 and 25. This should be fine as long as the actual grade is within this range. Also updated xselect.par so that the default mission is Suzaku rather than ASCA (about time!).

Keywords: HEAsoft, xselect, extractor

Monday, October 03, 2005

Suzaku XIS sky images

The current v0.1 processed files have sky image coordinates wrong due to an error in xiscoord. To get correct positions either multiply the image CDELT1 and CDELT2 by -1 or in the event files set TCDLT10 = 0.0002895 and TCDLT11 = -0.0002895.

Keywords : Suzaku