Chandra X-Ray Observatory

The AXAF Science Center

Minutes of AXAF Users' Committee (AUC) Meeting, June 25-26 1997

Committee members present: Jill Bechtold, Webster Cash, JP Caillault, Kathy Flanagan, Steve Kahn, Craig Sarazin, Fred Seward, Allyn Tennant, Mike Watson, Ray White

NASA HQ personnel present: Alan Bunner, Paul Hertz

The status of AXAF was reported by Harvey Tananbaum, ASC Director The status of the ASC was reported by Roger Brissenden, ASC Manager.

NRA Material

The panel had been asked to review the draft NRA plus the SIN in advance of the meeting. Their comments and concerns were discussed in turn. The AXAF NRA is the first to go through NASA's new, standardized NRA procedure and so will require reformatting and additional review to make it comply. This will not affect the procedures for proposers. NASA HQ also feels that Oct 1 is an unlikely date given the 11 weeks they require to review the material. "It will be released when it is ready." says NASA HQ.

The AXAF Observing Policy document is ready for approval at HQ and will be forwarded to the ASC shortly.

Funding of US co-Is on non-US-PI proposals has been misused in the past. The phase 2 review must affirm that the US co-I is valid and involved in the project. The standard wording will appear in the NRA and this will be carefully monitored, if/when necessary a policy will be drafted.

The AXAF NRA will also include opportunities for optional, linked but independent proposals for Education and Outreach funds (from a different pot of money).

A number of recommendations were made concerning specific revisions to the NRA. The most important conceerned clarification of rules for targets of opportunity.

SIN and Proposers Guide

The committee expressed concern over the schedule for the SIN and Proposers Guide, particularly since MSFC also wants a month to review them. The ASC noted that this material has now been separated from the NRA and so can be delivered to HQ around Oct 1st. Detailed comments on the SIN and NRA will be provided by the committee members directly to ASC User Support personnel. General comments included:

Proposal Submission Software


There was general agreement that this works well and is familiar to many. Concern was raised over the complexity of the ACIS parameters. The documentation needs to be improved and choices for the most common cases included. This is planned for the NRA once these are known. KF notes that they (MIT) have 4 common cases which she will provide. Excessive complex modes should be avoided because this will compromises the usefulness of the archive. A description of HESF needs to be added to the RPS help file.

Proposal Planning Tools:

the JAVA interface to planning tools is a major concern. Only 25% of the committee succeeded in running the software. This includes those who regularly use JAVA. The ASC needs to continue debugging to assess the magnitude of the problem. It could be a disaster at deadline time. The balance between being current and having users able to use the tools is a hard one to make.

Actions for the ASC:

The individual tools were discussed. Detailed comments will be made via email.

There was a general positive response to the roll visualizer, but still concern of JAVA which is needed for realtime update of display. SIM motion possibilities should be included. Other suggestions include linking to SPEX and a clean program to take an Einstein image (eg.) and make it a backdrop.

There was general opinion that MARX is a tool of primary importance. A 1-2 page walkthrough is needed (KF offered to do this) to help users. The AUC should be included in beta tests before general release with NRA.

Peer Review

The Committee discussed ways of avoiding conflict of interest during proposal handling and review. NASA HQ stated that it was very important that AXAF procedures be ``clean'', and above reproach. The technical evaluations should concern only the mechanics of instruments and observation parameters. The contents of proposals should be accessible to a minimum number of ASC staff, should be strictly treated as confidential information, and should not be discussed outside of the peer review.

The ASC will write exact rules for the review including a list of elements to be considered in the technical review and will send to NASA HQ and MSFC for review.

As a review model, the Committee considered 500 proposals split into 8-10 panels, each with about 8 members. There would be one ASC administrative aide (Ph.D) per panel. There would be duplicate subject panels so proposers could serve as reviewers. In any panel, no PIs on that group of proposals could be panel members and Co-I participation should be minimal. ASC staff participation as peer reviewers should be minimal. There should be 4-5 panel topics - probably: AGN and deep surveys, normal galaxies and clusters, normal stars, accretion sources, and diffuse galactic. The times assigned each panel might be the median request time, times the number of proposals.

Panel chairs and senior people could be picked before proposal submission. Panel chairs could help choose panel members and could decide who reviews what proposal.

Technical reviews will be done by instruments and not by subject. Written results of technical reviews will be available to the panels and will be sent to the proposers. The peer committee can suggest changes of instrument or instrument operating parameters to overcome technical problems.

There was discussion of using outside reviewers for proposals but most felt that this was not practical for the large number of proposals expected. The committee felt that it was okay to publish the list of reviewers after the review (but not the proposal assignments).

Budget requests will be considered in a second review. There is currently $10M available for cycle 1. 200-300 projects would thus average 33-50K/grant. Foreign proposals are ineligible. Multiple projects to one P.I. average less than single projects. Phase 2 proposals should contain budget, statement of work, and current and pending NASA support. The panel for the second review should consist or one or two members of each first review panel. The first part of the second review should be done electronically. Somehow, a level-of-effort should be assigned to each successful proposal; probably by the phase 1 panel. Care must be taken that the budget-panel members do not have input regarding money given to his/her own institution. The ASC will develop rules for the phase II review and submit to NASA.

AXAF Fellows

The AUC unanimously supported a proposal to have AXAF Postdoctoral Fellowships. It is valuable for promotion of X-ray astronomy in general and for AXAF in particular. It is worth dedicating part of the GO budget for support. The suggested arrangement would be similar to Hubble fellows but with 3 per year and a 3 year tenure. This leads to an estimated $500K per year steady state budget, about 5% of the anticipated budget for General Observers.


Key results and some unanticipated results of the MSFC/XRCF calibration were presented. In-flight calibration plans were outlined, suggested targets identified, and AUC comments solicited. The ASC will email a proposed list including observing times. General support was expressed for including some pretty picture-type observations for publicity purposes. These would be public immediately, as will all calibration observations.

Emission Line Project

An Emission Line Project was presented and discussed. This is a proposal to extend the AXAF calibration in order to provide grating spectra of sufficient quality to calibrate the standard plasma models which are in use by the X-ray community. This would require adding 150ks of time to the estimated 350 ks grating calibration. There was extensive discussion. The argument for centered on "If calibration is done, do it well." The points against were: The project should be peer reviewed; it is a large block of time; some data can be obtained in the laboratory. The committee voted in favor of including this in the calibration plan (5 to 3, with 2 abstaining) but would like to see the full in-flight calibration plan in parallel with its review by MSFC.

Instrument Complications:

The HETG team noted that the ACIS finite (40ms) shift time results in "bleeding" for high count rate sources.

AXAF and Snapshot observations

It is not at all clear that AXAF will have gaps in its schedule similar to those for HST. It was recommended that we hold off on this and to assess the actual on-orbit observing efficiency. Possible improvements in efficiency (such as this) can be best evaluated with experience in orbit. The minimum practical observing time given the overheads of slewing and locking on to a target (~15 mins) should be advertised.

Last year's recommendations to the Director

Concern was raised over the minimum computer power requirements to run data analysis software. The ASC needs to check this clearly and be conservative so that GOs can justify requests for workstations and prepare properly to handle the data.

New Members of AUC

Ray White has replaced Joe Patterson.

The chair rotation schedule was discussed. The present Chair stated that an outsider would command more respect from the ASC Director and from the MSFC Project office and was heartily in favor of such a change. The AUC was asked for recommendations for a new chair. If a new Chair can be selected, she/he should attend the next meeting.

Next Meeting

We will aim for mid-December at ASC.

Last modified: 12/01/10

Smithsonian Institute Smithsonian Institute

The Chandra X-Ray Center (CXC) is operated for NASA by the Smithsonian Astrophysical Observatory. 60 Garden Street, Cambridge, MA 02138 USA.   Email: Smithsonian Institution, Copyright © 1998-2017. All rights reserved.