ROSAT Status Report #66:
Sept 22, 1993
Survey Data available for background estimation
ROSAT PSPC all-sky survey data are now available from MPE for the background correction of images to the best estimate of the absolute surface brightness. Data will be provided from a limited region surrounding the target directions of pointed observations. The data are derived from integrated count rates in three energy bands (R12, R45, and R67 [Snowden et al. 1994a]). The data reduction is completely described and the all-sky maps will be presented in Snowden et al. (1994b). To summarize, the livetime and events in the three bands from the entire exposed region of the PSPC were cast in 10 s intervals into 40'x40' pixels on the sky. The pixel containing the center of the field of view received all of the counts and all of the livetime. Times of enhanced particle background and short-term enhancements were eliminated from the data. The residual particle background, scattered solar X-ray background, and long-term enhancement background were modeled and subtracted from the data. Finally, the count rates were scaled to be consistent with the on-axis effective areas, and therefore with the analysis procedures described in Snowden et al. (now available on ftp: see below).
Upon request, data from a 3x3 pixel grid where the central pixel contains the nominal pointing direction of the observation, will be made available to investigators. Count rates and count-rate uncertainties for the three bands along with the coordinates of the pixel centers will be provided. The request should be submitted to Dr. Roland Egger (MPE::ROE) at MPE. The request should include the name of the investigator, the coordinates of the observation in year 2000 right ascension and declination, the ROR number of the observation, and a short (abstract type) scientific justification.
Snowden, S. L., McCammon, D., Burrows, D. N., & Mendenhall, J. A. 1994a, ApJ, in press
Snowden, S. L. 1994b, in preparation
New ROSAT documents on the legacy ftp account
1) The sub-directory
rosat/publications/diff_bkgrd/
contains a PostScript version of the ApJ article "Analysis Procedures for ROSAT XRT/PSPC Observations of Extended Objects and the Diffuse Background" by S. Snowden, D. McCammon, D. Burrows, and J. Mendenhall
The article will appear in Ap.J in early 1994.
2) The PSPC Off-Axis Point Spread Function memo is now available on /caldb/docs/rosat/cal_ros_93_015/
The text is available as a latex file, cal_ros_93_015.tex and a post script file, cal_ros_93_015.ps. The figures are available in the same directory, as post script files. A hardcopy version of the memo is available on request to (span) LHEAVX::HUMPHREY (Sue Humphrey, if making such a request please include your full address in the email). Hardcopies will also be available at the ROSAT workshop Nov 8-10th.
3) A memo briefly discussing the PSPC spectral problem is in /caldb/docs/rosat/cal_ros_93_007/ again available in latex and post script formats. The figures (1a-1d) are the same as ratio1-ratio4.ps which were previously made available on the /rosat/problems directory.
The directory structure of the ftp account has been slightly modified and a map of the new rosat directory structure can be found under the rosat top level directory with filename FTPmap.txt
Note:
Status Report # 65 discussed the PROS 2.2.1 task "xray.xspatial.rosprf" which creates an image that models the on-axis PRF (also known as the PSF). As clarification of those comments, we note that "rosprf" can produce an image at any user-defined energy (i.e., the single energy value is selectable, NOT "hardwired"). Also, the previously-noted lack of a break to the power-law in the tail of the PSPC PRF provided by xspatial.rosprf will ONLY BE NOTICABLE at large distances from the source centroid (an energy-dependent distance, in all cases greater than ~7 arcmin).
HRI Report
Some users had experienced problems printing out the HRI Report document located on the legacy ftp account under
rosat/doc/hri/hri_report
These problems have been fixed, and details of how to print out the files contained in that directory can be found in the README file in that directory. Please contact us on rosat@rosserv if you have any problems with accessing any of the files on the rosat ftp area.
Matrices:
To clarify, we currently consider the 93jan12 PSPC response matrix to be most appropriate for data taken after 14 Oct 1991, and the 92mar11 matrix to be most appropriate for data taken before that data. We will update you on the spectral calibration as soon as possible.
Calibration Database
FITS format versions of the XSPEC pspc response matrices are available in the rosat/calib_data area of the rosat ftp account on legacy. These matrices are recognizable by their .rmf file extensions. They are more easily transportable than the old SF format matrices, and negate the need for the rdrsp and mkrsp programs, which were previously required to transfer XSPEC matrices and pha files between different types of machines. As before the matrices are 256 channels, except for the HRI matrix, which is a single channel (no spectral response available to date).
Files available are:
rosat/calib_data/pspc/cpf
pspcb_92mar11.rmf pspcb_93jan12.rmf pspcc_92mar11.rmf pspcc_93jan12.rmf
and rosat/calib_data/hri/cpf
hri_90dec01.rsp
cpf stands for calibration product file, which is appropriate to these matrices, in which the detector effective area, photon redistribution files and window corrections are convolved to make the "response matrix". These convolved files are compatible with XSPEC versions 8.2 and later. It should be noted that the FITS matrices can be used with old style PHA files and new FITS pha files within XSPEC (There should be no apparent difference to the user).
************************************************************************** -Redistribution of MPE bulletin # 21 ========================================================================= = = = ROSAT NEWS No. 21 --- 15-Sep-1993 = = = =-----------------------------------------------------------------------= = ROSAT Scientific Data Center at the = = Max-Planck Institut fuer Extraterrestrische Physik (MPE) = = Postfach 1603, 85740 Garching, FRG = =-----------------------------------------------------------------------= = e-mail addresses (Uli Zimmermann): = = rosat_svc@mpe-garching.mpg.de (Internet) or = = MPE::ROSAT_SVC (SPAN) = = ROSAT Service Area read-access via anonymous ftp: = = ftp rosat_svc.mpe-garching.mpg.de (130.183.72.180) user: anonymous = =-----------------------------------------------------------------------= = XUV Center: 29382::GXUVDC or GXUVDC@AIT.PHYSIK.UNI-TUEBINGEN.DE = = WFC Archive access via telnet/ftp ait.physik.uni-tuebingen.de = = user: xuv (password: xuv_archive) = =========================================================================
NETWORK ADDRESSES
This ROSAT NEWS has been sent out by email and, as exception, in parallel as letter to you. If you did not receive the email version, but would like to get the ROSAT NEWS regularly, please send us a short notice.
USERS WORKSHOP on November 3/4 at MPE
As already announced a Second ROSAT Users Workshop will be held at the ROSAT Scientific Data Center at Garching in November this year. This one and a half day workshop is mainly intended to present and discuss new science gained with ROSAT as well as other actual ROSAT items. We therefore hope that many of you take the opportunity to discuss their recent results with the ROSAT community. As in the last year there will be also the possibility to discuss special data analysis problems with our experts on an individual basis.
The meeting is planned to start on Wednesday, November 3, after lunch to allow for travelling in the morning and should close on Thursday in the later afternoon. Please contact us if you would like to include additional topics in the meeting agenda listed below.
We will be happy to see you at the meeting. A registration form can be found at the end of the ROSAT NEWS or can be accessed as file workshop.form from directory general in the ROSAT Service Area.
Topics planned for the workshop
- Short status of satellite, instruments and the mission future
- Status of the calibrations
- Present and future ROSAT Archives (short discussion)
- ROSAT papers (main body of the workshop)
- Discussion on data evaluation items (SASS, EXSAS, detection techniques)
- EXSAS demonstration: new facilities
PROCESSING
The following PSPC observations processed at MPE may show a bug on the cover page of the SASS output:
UK800413P, WG800382P-1, WG900379P-1
(Inserted U.S. addition)
The following additional PSPC observations processed at GSFC definitely show this problem:
US400262, US400280, US701411, US900495
Any observation for which the "Life Time Factor" values on the cover page are blank will have an erroneous average life time factor, leading to count rate/flux errors unless the user manually compensates for this problem.
Some of the involved observation intervals may show a blank instead of the correct mean life time factor and then the total mean life time value on the cover page is wrong. The bug is caused by the fact that the naming order of the intervals does not correlate with the time ordering of the intervals (which is not mandatory). The data are not affected. Since in EXSAS the PSPC mean life time is calculated directly from the data, data evaluation is not affected. The bug has been fixed in SASS release SASS6_5 (STEER7_3).
EXSAS/MIDAS
The EXSAS software is now also available for HP (RISC) workstations.
REGISTRATION FORM
for the R O S A T Users' W o r k s h o p
on 3rd/4th November 1993 at MPI fuer Extraterrestrische Physik in Garching
Begin: 3rd November at 14.00 End: 4th November at about 17.00
Name, First Name: ..........................................................
Institute: ..........................................................
Ich will participate at the Workshop .......... ..... .. (please tick)
definitely maybe no
Please reserve a Hotel room from .............. until ..................
Title of my talk (about 15 min.) - if appropriate:
...........................................................................
Please return this form as soon as possible:
per email: ROSAT_SVC@mpe-garching.mpg.de (Internet)
MPE::ROSAT_SVC or 28773::ROSAT_SVC (SPAN)
per FAX: 089-3299-3569
per letter: Wissenschaftliches Datenzentrum - ROSAT
MPI fuer Extraterrestrische Physik
Postfach 1603
85740 Garching
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