HEASARC Staff Scientist Position - Applications are now being accepted for a Staff Scientist with significant experience and interest in the technical aspects of astrophysics research, to work in the High Energy Astrophysics Science Archive Research Center (HEASARC) at NASA Goddard Space Flight Center (GSFC) in Greenbelt, MD. Refer to the AAS Job register for full details.

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May 1, 2023 : Reprocessed HaloSat Data Available

All Halosat data collected during the science operations from Oct 15, 2018 and Sep 29, 2020 were reprocessed (version hsuf_20221026) and are now available from the HEASARC archive. The main changes in the reprocessing are:

  1. The alignment file is now used when the pipeline runs the ‘prefilter’ tool. Some of the columns in the output of prefilter are added in the HK FITS file. The alignment file improves the accuracy of the right ascension and declination, as well as roll, for the spacecraft.
  2. In the HK FITS files, the POSITION and VELOCITY were incorrectly formatted. This has been fixed.
  3. A bug fix corrected a channel offset present in data processed with older versions of the pipeline. The offset required a gain shift in spectral fitting. With the new data, the gain shift is no longer necessary when fitting the spectra.
  4. The header keywords DATE-OBS and DATE-END were changed from TAI time to UTC by adding 32 seconds.
  5. Corrected the PDF files reporting the observation log for specific sequences that were unreadable with the previous pipeline version.
  6. The arf file has been updated to include the edge at 1.8 keV. This new arf, hs_sdd_all20180701v002.arf, has ben ingested in CALDB. When using this arf, it is no longer necessary to include an edge in the spectral fitting.

The analysis guide and the backgroud notes have been updated.

The reprocessing document explains in detail the changes for the final data processing as well as the changes included in the arf.

The database halomaster has been updated and a new database halotimelg is now available to allow searches by time intervals.