skip to content
 
ASCA Guest Observer Facility

The ASCA Japan/US Merging Charter


The following document is the charter used by the Japan/U.S. ASCA merging committee to construct the ASCA program for an observing cycle. Please note that this charter is a set of guidelines, and not hard and fast rules. Every effort is made during the merging process to maintain a spirit of collaboration, and to treat each target overlap fairly. In practice, the guidelines are followed closely, and very few exceptions are made.

A charter for the execution of the ASCA general program (revised 3/95)

1. Target selection

1.1 The US and Japan reviews should assign one of three priorities to each accepted target A, B and C. The A class absolutely must be observed. The B class should be observed if observation constraints allow. The C time proposals are an additional pool of desirable targets that provide:

  • a safety net that will ensure something is always in the program to be observed (e.g. to account for source availability on the sky, or unexpected operations problems)
  • to allow for a reduction caused by the merging of the US and Japanese programs.

1.2 The goal of the target selection process is to produce a list of targets representing approximately 125 percent of the available observing time, with approximately 40 percent for A, 60 percent for B and 25 percent for C.

1.3 All time constrained observations will be priority A or B. The total time available for constrained observations will not exceed 10 percent of the total available time. No target of opportunity (TOO) proposals will be allowed.

1.4 Priority A observations will not be considered completed unless they have received 95 percent of the requested time. Priority B and C observations are considered complete if they have been observed for 70 percent of the requested time.

1.5 A proposal submitted by a joint US-Japan team can request observing time only from either Japan or the US (proposals submitted for time to both places will be rejected). [A US observer who is part of a proposal submitted to Japan can submit a "funding only" proposal to NASA.]

2. Merging committee

The merging process will be made by a Japan/US "merging committee," made up of four representatives from Japan and three from the US. Nonvoting technical helpers and observers may be present as well.

3. Merging procedure

3.1 The intent of the GO program is to encourage collaboration between the US and Japanese astrophysics communities. In this spirit, targets common to both national programs will be combined into a single collaborative observation, unless the proposer explicitly requests otherwise. Guidelines for the implementation of this are contained in the appendix to this document.

3.2 Merging will be done on a target by target basis. The intent is to make the merging process as automatic as possible. In particular, it should be unnecessary for the merging committee to judge targets on scientific merit by reading proposals.

3.3 Two types of targets utilize the 25 percent collaborative time: i.) those for which collaborative time has been explicitly requested, and ii.) targets accepted in both national programs.

3.3.1 In the event that the amount of time from these targets does not fill the 25 percent, targets from the US program whose priority falls outside the highest remaining 15 percent will be assigned a Japanese collaborator until the time has been filled. [It should be noted that in this circumstance, some Japanese targets must be removed from the program.]

3.3.2 In the event that these targets account for more than 25 percent of the available time, the highest ranking collaborative proposals are kept. The remainder are restored to the national program where they had the higher priority. Implementation details are contained in the appendix.

3.6 Proposals for the same target requiring different observation modes or different time constraints may be considered as non-overlapping and may be removed on a case by case basis from the merged list.

3.7 The final lists will be adjusted so that 40% of the observing time has priority A, 60% has priority B and 25% has priority C, with this balance maintained across the three groups of targets (Japan, US, and collaborative).

3.8 Decisions made by the merging committee are final, subject only to change upon concurrence by the respective Project Scientists that a technical error has been made.

4. Proposal Database Software

The US guest observer facility will provide to ISAS proposal handling software, identical to that used in the US. This will be used to keep a record of all US and Japan proposals, targets, priorities, and the final merged program. It will also be used to detect target clashes between the two programs, and to flag those which require special attention by the merging committee.

5. Observation guidelines

Each national support team is responsible for providing the operational details (e.g., detector modes) for the targets in its program. Details for collaborative targets will be agreed upon jointly.


Appendix to ASCA general program charter Implementation of target merging

(revised 9/95)


1. Creation of the collaborative target list

Targets for which collaborative time was expressly requested (US and Japanese investigators on proposal), and those which appear as expressly collaborative in one list and in the other national list, automatically enter the collaborative program.

A target for which collaborative time was expressly requested enters the collaborative list at the observing priority that a national committee assigned it. A target for which collaborative time was expressly requested and which appears in a national progam enters the collaborative list at the higher of the two priorities assigned by the respective national committees.

b. The second set of targets which serve as candidates for the collaborative list are those listed in both the US and Japan programs. These will be identified by matching names and coordinates (within 10 arc minutes).

The disposition of the overlapping targets is the responsibility of the Merging Committee. In general, the committee will decide to merge the overlapping targets into a single observation. The default observing time is the longer of the two proposed, and the default priority is the higher of the two.

Targets from this group will be placed in the collaborative list, until either:

  • all common and collaborative targets have been included (undersubscription)
  • or a total time of 25 percent x 1.25 of the available time has been accumulated (oversubscription).

The merging committee decides upon the Prime Principal Investigator (PPI) and Co-Principal Investigator (CoPI). Generally, the PPI will be the PI whose target was accepted at higher priority within the national program; but the merging committee will attempt to seek a balance among the PPI's selected.

2. ESA/Japan Targets

A Japan/ESA agreement entitles investigators from ESA member nations a 10 percent share of the ASCA observing time. The ESA time is drawn from the Japanese share exclusively. Formally, this time is ESA/Japan time and Japanese collaborators participate in all observations. Overlaps between ESA/Japan targets and U.S targets are resolved as follows.

In most instances, if an ESA/Japan target overlaps with a target involving U.S. investigators (U.S. or collaborative), the ESA/Japan target is dropped.

The only circumstances in which the merging committee might consider making an exception is if the U.S. target is priority C and the ESA/Japan target is highly ranked. In this case, the U.S. target if selected is unlikely to be observed. The merging committee can decide to drop one of the observations or to merge them.

For the purposes of oversubscription and undersubscription, the ESA/Japan targets are considered part of the Japan target list.

3. Treating undersubscription and oversubscription

In the event of undersubscription of the collaborative target list, the following procedure is used to fill up the time allocated to collaborative targets (1.25 x 25 percent):

  1. An effort is made at all times to maintain the priorities assigned to the targets by the national review committees.
  2. The highest ranked US targets in each priority class, representing 15 percent x 1.25 of the total available observing time, are set aside. These represent the US share of the observing program.
  3. Remaining US targets are placed in the list of collaborative targets. This is done in order of descending priority, until the collaborative time has been filled. Suitable Japanese collaborators are identified and incorporated into the observing team.
  4. The remaining US targets are dropped, as are all Japanese targets whose priority places them below the total observing time allowed for Japanese targets (60 percent x 1.25).

In the event of oversubscription, the following procedure is used to ensure the higher priority targets from each national program are still observed.

  1. For targets with different priorities in the two national programs, the target with the higher priority is kept in that program, and that with the lower is dropped, until each national program is fully subscribed.
  2. If the targets have equal priority, the target with the longer time is kept in its national program.
  3. If the targets have equal priority and time, the merging panel will agree on which program in which the target is to be accepted.
  4. "US time only" proposals

A US PI has the option of requesting "US time only" on his proposal. If an accepted target from such a proposal overlaps with a collaborative target of higher priority, it is dropped. In the event it overlaps with a collaborative target of equal or lower priority, the merging committee decides which is kept or whether the observations should be merged. If it overlaps with a Japan target, then the merging committee will decide whether the targets should be merged, or one dropped.

5. Merged Targets

a. Composition of the team

The initial observing team for the merged proposal consists of: the PPI and all named coinvestigators from his/her proposal; and the CoPI and all named coinvestigators from her/his proposal. Lists of the team membership will be provided to the PPI and CoPI by the GOF's.

The PPI and CoPI should consult one another before including additional coinvestigators in the analysis effort. The PPI and CoPI should respect each other's propietary rights at the national level by not adding new collaborators from the counterpart's country without explicit concurrence of the other.

b. PPI and CoPI Roles

As lead investigator for an observation, the PPI has primary responsibility for specifying the observing parameters. He is also responsible for coordination of the analysis effort. It is expected that the PPI will consult with the CoPI and other team members during all phases of the investigation.

As lead investigator in an observation for his respective national program, the CoPI serves as contact point between the PPI and his team.

Data are sent separately to the PPI and the CoPI. It is their responsibility to disseminate them to other team members.



If you have any questions concerning ASCA, visit our Feedback form.

This file was last modified on Tuesday, 23-Apr-2002 11:48:16 EDT

NASA Astrophysics

  • FAQ/Comments/Feedback
  • Education Resources
  • Download Adobe Acrobat
  • A service of the Astrophysics Science Division (ASD) at NASA/ GSFC

    ASCA Project Scientist: Dr. Nicholas E. White

    Responsible NASA Official: Phil Newman

    Privacy Policy and Important Notices.