ROSAT status report #5

June 10th 1991

Spacecraft status:

After the gyro failure on May 12, ROSAT remained in safe mode until May 18, at which time attitude control was successfully regained. Over the subsequent four days, pointings at a series of attitudes took place, including a day-long integration on an AO1 deep survey target (the "Lockman hole"). Contrary to rumor, there was no several-day-long pointing at a single attitude.

ROSAT has been observing AO1 targets in reduced pointing mode since May 22. Only two days of pointing have been missed in that time. We include below those targets that have been observed, or are scheduled through June 21. All scheduling is done by GSOC, additions to the schedule will be made available as they are received. The numbers in parentheses are the target priorities, these are followed by the scheduled observing times from the ORIGINAL AO1 timeline.

Operations this past week has been hampered by a couple of difficulties. First the observation of SS Cygni was lost due to an inability of the star tracker to locate guide stars. Secondly, an increased level of solar activity has increased the radiation environment. Even though more conservative values are being used to define the radiation belt regions in which the PSPC is shut off, the detector has safed itself several times outside this region as a consequence of high radiation. As of June 14, there has been no abatement in the increased background level.

        New ROSAT Timeline
        __________________

        20 May - 21 May  U?  Lockman Hole       Hassinger 
        22 May - 23 May  US 2 NGC3998           Reichert (2) 10 
        23 May - 24 May  US 2 NGC3998           
        24 May - 25 May  WFC calibration target 
        25 May - 26 May  UK 3 A2218             Stewart (2) 20
        26 May - 27 May  US 2 GL 411            Giampapa (2) 10
        27 May - 28 May  WG 3 MKN 231           Kollatschny (3) 10
        28 May - 29 May  WG 3 1E1235+6315       Thomas (3) 10
        29 May - 30 May  WG 2 1116+215          Ulrich (2) 10
        30 May - 31 May  US 3 GD140             Shipman (3) 10
        31 May -  1 Jun  UK 2 NGC4151           Shanks (1) 10
         1 Jun -  2 Jun  WG 3 NGC4490           Snowden (3) 10
         2 Jun -  3 Jun  US 2 3C280             Lawrence (2) 10
         3 Jun -  4 Jun  WG 3 DELTA LEO         Schmitt (3) 20
         4 Jun -  5 Jun  WG   1202+281          Ulrich (3) 10
         5 Jun -  6 Jun  US   NGC4736           McCammon (2) 10
         6 Jun -  7 Jun  US   NGC4736           
         7 Jun -  8 Jun  WG   MKN231            Kollatschny (3) 10
         8 Jun -  9 Jun  WG 2 M101              Snowden (2) 20
         9 Jun - 10 Jun  WG 2 SS CYG            Verbundt (3) 10 (mispointed 
                                                by 3.5 degrees) 
        10 Jun - 11 Jun  WG 2 CYG X-2           Hassinger (1) 20
        11 Jun - 12 Jun  800066 WG   Stephan's Quintet     Kirk (3) 10
        12 Jun - 13 Jun  US   N79-299A              Burns (2) 15
        13 Jun - 14 Jun  WG   COM16             Thomas (2) 4
        14 Jun - 15 Jun  WG   ON 231            Thomas (2) 41
        15 Jun - 15 Jun  WG   B2 1215+30        Rosso (3) 1
        15 Jun - 16 Jun  US   COMA5             White (1) 5
        16 Jun - 17 Jun  US   COMA2             White (1) 5
        17 Jun - 18 Jun  US   COMA1             White (1) 5     
        18 Jun - 19 Jun  US   COMA9             White (1) 5
        19 Jun - 20 Jun  UK   HZ43              Barstow (1) 2
        20 Jun - 21 Jun  US   Abell 1758        Mushotzky (2) 8 
        21 Jun - 22 Jun  US   Abell 2634        Burns (2) 25
        22 Jun - 23 Jun  WG   B21308+32         Thomas (3) 10
        23 Jun - 24 Jun  UK   Deep Survey       Branduardi-Raymont (2) 100
        24 Jun - 25 Jun  UK   Deep Survey       
        25 Jun - 26 Jun  WG   1411+442          Bierman (3) 8
        26 Jun - 27 Jun  US   JN1               Petre (2) 4
        27 Jun - 28 Jun  WG   HR8905            Schmitt (3) 6
        29 Jun - 30 Jun  US   Mkn 335           Turner (1) 5
        30 Jun -  1 Jul  UK   1E1346+266        Mason (3) 11
         1 Jul -  2 Jul  US   Abell1795         Arnaud (3) 50
         2 Jul -  3 Jul  WG   Alp Cep           Schmitt (2) 7
         3 Jul -  4 Jul  US   II Peg            Huenemoerder (3) 10
         4 Jul -  5 Jul  US   PG0027+260        Kahn (3) 10

ROSAT Grant Funding:
--------------------

All the grant processing for A01 proposals that were scheduled in the long-term timeline has been completed, but a number of issues (not the least of which is the uncertain nature of the implementation of the pointing program) has held up the awards. The agenda for the current meeting of the Rosat International Users Committee includes the consideration of options for the manner in which the selected A01 proposals will be rescheduled, and the funding will then be dispensed accordingly. This policy will be discussed completely in the next circular, or whenever it is finalized.

Level 1 Processing:
-------------------

SASS 5.0.4 has been installed and has processed some AO1 data (only test cases). There still exist problems with having the correct values for some of the parameter limits in the SASS software. This results in many good photons being labeled as bad and not getting processed. One problem was with a bad PSPC high voltage sensor that labeled the majority of time intervals in an observation as occurring during a period of unacceptable PSPC voltage settings. The parameter limits for high voltage in SASS were adjusted to circumvent this problem. GSFC personnel are being sent to MPE to resolve these problems and to install the "production" version of SASS (version 5.0.5).

GSFC will start processing PCV phase data starting June 13 using SASS 5.0.4. Most of the aforementioned problems have been solved for this dataset and hence good science can be done.

Level 2 Software:
-----------------

PROS:

The PROS Advisory panel, which was described in the previous ROSAT Status Report, has now completed its evaluation of the PROS software. The purpose of the Panel was to quickly review the current status of the PROS software and to make recommendations on the priority of improvements to be made during an intensive 2-month software development period by the SAO programming staff. Each panel member was responsible for reviewing one or more of the 3 PROS packages, which resulted in a a final list of about 100 problems or suggested enhancements related to the PROS tasks. The Panel met twice at the AAS meeting and made the following general recommendations for the near-term software development:

Spatial Package:

improve the way the image blocking factors and sub-sections are communicated between different tasks. In particular, region specifications generated by SAOimage should be converted in an automatic manner to physical pixel coordinates needed to extract data from unblocked qp files.
ensure that WCS information is correctly propagated in tasks which create images or qp files from other images or qp files, and is used in all tasks which require information about coordinate systems.
provide correct vignetting and exposure maps for both PSPC and HRI.
provide off-axis point spread functions to be able to distinguish between point and extended sources in the outer parts of the ROSAT field of view, and provide a goodness-of-fit statistic from the spatial modeling package.
improve extraction of data from complex regions - i.e., multi-vertex polygons and regions within iso-intensity contours.

Spectral Package:

concentrate on the ability to extract the spectral information from ROSAT images, including extended sources, for input into other software packages.
for the near-term, inform users that the XSPEC software package (originally developed for the EXOSAT project) can provide additional spectral modeling capabilities that are not provided within PROS and that spectral data extracted with PROS can be input to XSPEC (via a simple converter program developed at and available from the GSFC GOF). Note this is not a recommendation to abandon spectral analysis within PROS. The panel is unanimous in its feeling that PROS develop and maintain this capability.

Timing Package:

given the limited available programmer resources, the panel recommended that little work be done on this package for the next release. The biggest issue to be resolved is to determine how (or even if it is possible) to take into account the modulation of source flux introduced by the wire grid in the central field of view. The scientific requirements for solving this problem must be resolved before the software can be developed, and GSFC will raise this issue with MPE in the near future.

General:

improve the PROS documentation. In particular, provide more ROSAT specific examples; identification of useful IRAF tasks; an overview of what's available in PROS and where to find help; and summaries of PROS tasks.
the SAO PROS team should take fuller advantage of IRAF expertise at NOAO, STSci, and elsewhere. A number of problems, such as mosaicing images and dealing with off-axis point spread functions, are addressed in other IRAF packages. The PROS team should actively seek out and implement tools adopted from IRAF, ST-SDAS, etc. into the examples and manuals written for PROS, and the user support personnel at both Guest Observer Facilities (i.e., SAO and GSFC) should learn IRAF so that they can properly support the users they deal with.
There should be a standing committee to monitor progress toward the recommendations made by the advisory panel, to serve as sounding board for the PROS team, and to funnel back general user reaction to the PROS system. This committee should have some PROS development team people as members to provide technical insight into PROS. Also, cross-membership with similar committees dealing with StSci and NOAO software packages is desirable.

Many other specific recommendations were made in each of the panel members' reports. The SAO staff will now incorporate as many of these improvements as they can in the next PROS software release (about two months from now). Additional enhancements to the PROS software will of course continue to be made in future releases (which are anticipated at intervals of approximately six months).

IDL:

IDL procedures which will allow observers to look at the information stored in their auxiliary FITS files continue to be developed. Thus far, the procedures include routines to read and plot data from the split orbit (.SO) files as well as from the PSPC event rates (EVR) files. Routines which give directories of both 3D binary and STSDAS ASCII table files are also available. Alpha test versions of all of the routines are available; contact Gail Reichert for more information (HEAVAX::REICHERT).

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