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______________________________________________________________________ * * * ISDC-News 09-APR-2009 * * * ______________________________________________________________________ Postdoctoral and PhD research positions in high-energy astrophysics =================================================================== There are several open postdoctoral and PhD research positions at the ISDC Data Centre for Astrophysics. Please refer to the information in the ISDC-News of 10-MAR-2009 ______________________________________________________________________ INTEGRAL Off-line Scientific Analysis ===================================== The next release of the offline scientific analysis (OSA), version 8.0, is planned for the May time frame. The main focus for this release will be JEM-X where there will be major improvements in image reconstruction. In addition, this will be the final release of OSA for both the Solaris and MacOS/X PowerPC platforms. Future releases will be on Linux and MacOS/X on Intel. JEM-X changes ------------- The JEM-X software is being completely revised for the OSA 8 release. The changes should lead to a very important reduction in the systematics uncertainties on the flux measurements. The sky image reconstruction by the j_ima_iros tool, will become the baseline flux-extraction method for source spectra and lightcurves production. It will, however, still be possible to extract spectra from mosaic images. j_ima_iros will take into account the measured electronic efficiencies of both JEM-X units, as well as systematics effects - like those due to the collimator - which have been redetermined experimentally. Improved energy calibrations and gain determinations are achieved by taking into account short-term temperature variations. With these changes it is foreseen that a single ancillary response function, valid for both instruments, could be adequate for the whole mission. SPI changes ----------- The gamma-ray spectrometer SPI had a third detector failure in February 2009 at the beginning of revolution 776. Despite intensive effort by the SPI team and MOC, the detector #5 could not be recovered. SPI is currently working with 16 out of its 19 Germanium detectors. The SPI software has been updated for OSA 8.0 to ignore the dead detectors after their failures. As for the two previous failures, a new response file (IRF) will soon be provided by the NASA/GSFC team to take this change into account in the SPI analysis. The SPI team at the MPE in Garching provided a new software package for SPI spectral extraction based on the maximum entropy approach. This will be included in OSA 8.0 to allow the user to have two independent ways for SPI analysis: the usual spi_science_analysis using the spiros method and the new spimodfit_analysis script. ______________________________________________________________________ INTEGRAL Reference Catalogue ============================ A new version of the INTEGRAL General Reference Catalogue is available at: http://isdc.unige.ch/?Data+catalogs This version 30 of the catalogue has been updated with all the new detections, identifications, refined X-ray positions and possible counterparts up to March 12, 2009. It now includes 1703 sources, 576 of which detected at least once by IBIS/ISGRI. ______________________________________________________________________ Improved time correlation ========================= Precise time reconstruction is important for the study of fast variability from gamma-ray bursts or anomalous X-ray pulsars (AXP) and for phase determination of pulsars. The time correlation was affected by several problems like ground station delays and software problems. Most of these problems have been understood and corrected. A number of time correlation records were also eliminated. A new time correlation has been derived from the beginning of the mission. It will be used for a complete reprocessing of the data that has started at the ISDC. Users requiring precise timing can already download the new time correlation information and auxiliary information at: http://isdc.unige.ch/?Soft+download [Make sure you give write access before untarring and set the files back to read only afterwards.] The reprocessed data will also include an offset of the SPI anti-coincidence shield (ACS) timetags to align the ACS timing with that of the other instruments. Note however that this is already taken into account since a long time in the generation of all the ACS gamma-ray burst data products. ______________________________________________________________________ IBIS/ISGRI energy calibration ============================= The IBIS/ISGRI energy calibration depends on the total dose received by the detector pixels in form of charged particles. This is measured by the INTEGRAL radiation environment monitor (IREM) aboard the spacecraft. This radiation dose is collected mainly during perigee or during strong solar flares. The calibration database include an IREM dose file that needs to be updated regularly otherwise the software performs some interpolation. Even if the interpolation implemented in OSA 8 will be even better it cannot take new solar flares into account. We therefore recommend users to update their calibration database regularly following the method described below. ______________________________________________________________________ Update of the calibration database ================================== INTEGRAL calibration files are stored in the repository branch for instrument characteristics (ic/). You can easily upgrade them to the most recent version by running the following command to download the latest release to your local directory where the INTEGRAL data are installed, which is defined in the $REP_BASE_PROD environment variable: rsync -Lzrtv isdcarc.unige.ch::arc/FTP/arc_distr/ic_tree/prod/ $REP_BASE_PROD The "rsync" command is part of most commonly used Linux distributions. If you run the command repeatedly, only the additional or updated IC data files will be downloaded into the $REP_BASE_PROD/ic/ and $REP_BASE_PROD/idx/ic/ directories. ______________________________________________________________________ Please update your e-mail address in the ISDC distribution list via: http://isdc.unige.ch/?Newsletter+email |
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