Wednesday, April 30, 2008

xspec patches

A few new patches have been added recently. 12.4.0x fixes a number of problems that showed up when using the new g++-4.3.0 compiler and when using gcc on Solaris platforms. This patch level is released as part of HEAsoft 6.4.1. 12.4.0y improves the handling of cases when the L-M algorithm pegs a parameter due to a zero or negative pivot value in the Hessian. 12.4.0z keeps the fit valid when the fit method is changed. This allows the improve command to be run after an L-M fit. 12.4.0aa is a fix to allow filenames prompted for by the fakeit command to being with a / ie to be absolute paths. Patches available from the usual place.

Thursday, April 24, 2008

xselect: Chandra response generation

Overhauled the response generation option on "save spec" for Chandra ACIS data. I added an extended? parameter to specify whether the source is a point source or not. For a point source the arf is created using mkarf, and for an extended source mkwarf is used. The rmf is generated using mkrmf or mkacisrmf depending on whether CTI correction has been performed. The script checks keywords in the spectrum to determine which is appropriate. Note that to find some of the auxiliary files required xselect should be being run in either main directory for the dataset or in a directory one level down (eg secondary).

Note that I also modified the FITS region extension written by extractor so that the EXTNAME is REGION and EXTVER is used to track multiple extensions. This is a change from an EXTNAME of REG001## and is made to conform with the CXC standard defined by McDowell & Rots. There may be an issue here is XMM-Newton SAS routines are expecting the REG001## names.

Tuesday, April 22, 2008

Science 2.0

SciAm has a brief survey of Web 2.0 applications in science. In particular, it argues that putting scientists working notes on-line will foster greater communication and collaboration.

Monday, April 14, 2008

reading old RMFs

Tahir points out that the BeppoSAX RMFs don't work in rbnrmf. The problem is that these files have only RMFVERSN='1992a' and do not have the HDUVERS keyword that the software now requires. The workaround is to add HDUVERS='1.0.0' to the MATRIX extension. I've updated the relevant subroutines to check for RMFVERSN if HDUVERS is not found.

Tuesday, April 08, 2008

setplot wave units in xspec

Changed the plotting units for the setplot wave option. Now showing f_nu and variants instead of f_lambda. The model and ufspec y-axis is photons/cm^2/s/Hz; emodel and eufspec are in Jansky (1e-23 erg/cm^2/s/Hz); eemodel and eeufspec in keV Jy. The latter is a bizarre mixed unit but it isn't clear to me what to use here. It might be an idea to have an option for the user to switch between f_lambda and f_nu.

Updated: decided that for the eemodel/eeufspec plots the units should be erg/cm^2/s corresponding to standard nu F_nu plots.

Independently, I fixed an error in setting the y-axis range for eufspec and eeufspec under setplot wave.

Wednesday, April 02, 2008

genrsp v2.02

Added an option for the resolution varying linearly with either the energy or the wavelength.