Chandra proposal submission and review will be conducted in two stages to minimize the burden of proposal preparation.
Once the targets are identified, the Chandra X-ray Center (CXC) is responsible for generating the schedule of observations or science timeline. The timeline is determined for the most part by satellite and observing constraints, as specified in the proposal and as recommended by the peer review. These constraints are described in detail in the Chandra Proposers’ Observatory Guide (POG) (http://cxc.harvard.edu/proposer/POG/index.html). Proposers may also specify additional constraints such as a particular time or time interval during which an observation must take place. Proposers should note that time-constrained observations are difficult to accomplish efficiently and will be limited to ~15% of the total number of observations selected. Details of constraint classification and quotas are described in Section 5.2.8.
The Stage 1 proposal must include:
The page limits are listed in Table 5.2. The proposal must be submitted electronically (see Section 5.3 for proposal submission instructions). The information will be entered into a database that will be used in cataloging and evaluating proposals and, for those observing programs selected for implementation, will be transferred to the Observation Catalog. The forms must be completed in the requested format. Cost sections should not be submitted for the Stage 1 scientific review. However, proposals for the Archival Research or Theory/Modeling projects must include a preliminary cost estimate and a brief narrative describing the proposed use of these funds within the science justification section of the Stage 1 proposals. Formal cost proposals will be considered as part of the Stage 2 process.
To be eligible for funding for either PI or Co-Is, a U.S. Institution MUST be specified on the RPS form, and must be the primary institution of the investigator seeking funds.
Institutional endorsement information (name of administrator, administrative authority, and administrative institution) are optional for the Stage 1 proposal, but may be provided by separate hardcopy (to the address in Section 1.7) in those cases where the proposing institution requires them. In all cases, institutional endorsements are required for the hardcopy submission of a Stage 2 cost proposal.
The abstract on the Cover Page Form is limited to 800 characters, including spaces between words. If the abstract exceeds this length, it will automatically be truncated at 800 characters when entered into the database.
The RPS proposal Cover Page Form requires one or more keywords describing proposal science. Selected keywords may be used to facilitate preliminary matching of proposals to reviewers, as well as archive searches.
The RPS target forms must include full specification of the observing parameters for every target and for every observation of that target. In complex cases that cannot be entered on the forms, please enter a detailed description in the Remarks section of the target form and/or contact the CXC HelpDesk for advice. If any additional constraints or preferences are included in the Remarks, you must set the corresponding flag (above the Remarks) to ensure that they are implemented. Incorrect information will jeopardize the acceptance of a proposal. The information in the RPS forms will take precedence over any contradictory/different information described in the proposal science justification. Any observing parameter information included in the science justification and not in the RPS forms will not be accepted. Additional constraints or changes to observing parameters requested after the proposal deadline will only be considered in very unusual circumstances and will require approval by the CXC Director.
For proposals involving observations, the proposer is urged to be as accurate as possible when entering the position of the target, since even small errors can seriously reduce the quality of the data. Positions must be given in equinox J2000.0 at the current epoch. Upon proposal submission, the RPS will run a crosscheck of coordinates and object names entered with the SIMBAD catalog and will notify PIs should any errors be found in this cross-check. If after such notification there is time before the deadline, the PI should re-check the target(s) in question and, if necessary, re-submit his or her proposal (both target form and science justification) with corrected target name and coordinates. If the deadline has passed, the PI should contact the CXC, via the HelpDesk, (as soon as possible, to make any necessary corrections.
Proposers requesting more than one target, or multiple pointings at a single target, should assign a Target Number that indicates the order of priority. Prioritization will aid the Selecting Official in the event that a reduction in observing time is recommended. In such cases, every attempt will be made to honor the highest priority targets.
On the RPS form, additional targets with the same observing parameters can be added by using the Add Target button. If a large number of targets are requested and the web version becomes slow, the PI can switch to the email version of the RPS via the RPS email button.
Multiple observations of a large target/sky area where all pointings are within 1 degree of their nearest neighbor may be classified as a grid and should be allocated a unique grid name in the RPS form. For a large number of pointings, proposers may elect to enter grid specifications rather than the full list of targets. If the proposal is approved, the PI must send the full target list to the CDO as a tab-delimited ASCII file with three columns: ObsId, RA, Dec, where RA and Dec are in decimal degrees.
The proposal must state clearly the scientific objectives, with relevant background and reference to previous work. The reviewers will not necessarily be specialists in your particular science area, so include all relevant information in your proposal. Show how the proposed investigation may be used to advance our knowledge and understanding of the field. Justify the use of Chandra or its archival data to accomplish the objectives, in contrast to using other available observatories or archives. If X-ray data from Chandra, XMM-Newton, or any other facility exists, justify the need for additional Chandra data to achieve the scientific objectives. To search for other data, see e.g., HEASARC Browse web page (http://heasarc.gsfc.nasa.gov/db-perl/W3Browse/w3browse.pl). Any constraint on the observations must be clearly stated and justified. Discuss the data analysis program required to attain the science goals including the scope of the effort.
For all observing proposals, the proposer needs to justify the use of the Chandra X-ray Observatory. The proposal should show how the particular details (observing time, instrument, instrument mode, etc.) of the proposed observations allow one to achieve the stated scientific objectives. State how targets or pointing directions were selected. List assumptions about source intensity, surface brightness, and spectrum. Estimates of both counting rates and total counts needed to accomplish the investigation must be provided. It is in the proposer’s best interest to allow a reviewer to understand the assumptions and to be able to easily reproduce the estimates of the counting rate(s). The proposer should also demonstrate that the estimated counts are sufficient to extract the desired science results from the observation. The impacts of pileup on the observed energy spectrum should be addressed for observations with ACIS, HETG/ACIS, or LETG/ACIS of even moderately bright sources. Proposals for observations that might encounter pileup must explicitly discuss the plans for dealing with such data in order to demonstrate a thorough understanding of the implications for their proposed research. To maximize the scientific utility of the Chandra archive, proposers are encouraged to select more than the minimum number of ACIS CCDs that their core science requires. While a maximum of 6 CCDs can be selected, observers are encouraged to require 5 or fewer CCDs - if their science objectives are not significantly affected by turning one or more CCDs off - and designate others as optional: this assists with thermal management of the Observatory. Please see the Proposers’ Observatory Guide (POG, Section 6.20.1) and the webpage http://cxc.harvard.edu/acis/optional_CCDs/ optional_CCDs.html concerning optional ACIS chips.
Proposals that request funding for Archival Research must include a discussion of any publications that already have resulted from the observations and an indication as to how and why the proposed research will significantly extend these results. Proposals for Theory/Modeling must discuss how the proposed research will further the understanding of Chandra data.
Proposers interested in Archival Research should also discuss how and why the specific archival data are sufficient to meet their objective(s). Furthermore, such proposals must address the analysis tools to be used, their suitability for accomplishing the investigation, and the proposer’s ability to apply such tools to the project. Archival Research and Theory/Modeling proposals should include a brief budget narrative within the science justification section.
Proposers wishing to apply for joint time also need to include a section entitled “Technical Justification of Joint Facilities” in which they address the technical feasibility of the observations using the relevant observatory(ries) in their proposals. This must include the visibility of the target by the observatory(ries) in question (particularly in the case of a request for simultaneous observations).
The proposer may desire to place constraints (e.g., monitoring, coordination with observations at other wavelengths, uninterrupted observing periods, roll angle, etc.) on the proposed observations. Such constraints are discussed in Section 3.4.2 of the POG. Constraints limit the flexibility of scheduling and, therefore, reduce the overall observing efficiency. They may also cause an observation to be unfeasible if, for example, they require violation of the pitch angle restrictions (Section 2.3). Thus, proposers should carefully consider the impact of a request for a constrained observation and provide scientific and technical justification. Proposers should note the potential impact on time-constrained observations produced by interruption by a TOO or other unanticipated events. An observation with very restricted time or roll constraints may, if bumped or otherwise rescheduled, be delayed six months or more to allow these constraints to be met. No more than 15% of Chandra observations in this Cycle will be allocated to constrained observations (see below). All constraints must be specified in the RPS forms or, if not possible, in the “Remarks” field with the “Constraints in the Remarks” flag set. Any constraints not so specified will need special handling and will be implemented only on a best effort basis. Additional constraints, beyond those proposed and recommended by the peer review, will be considered only in extreme circumstances and must be approved by the CXC Director (request via email to the CXC HelpDesk). Proposers should use the PRoVis tool, available on the CXC website, to confirm that a constraint (or monitoring sequence) which they are considering does not require observations at pitch angles and/or durations that are not feasible (as directed in Section 2.3). Information on the periods of time when Chandra observations are allowed due to its passage beyond the Earth’s radiation zone is provided at http://cxc.harvard.edu/proposer/orbits.html. The maximum uninterrupted exposure time for a target observed at a given pitch angle can be estimated from the MaxExpo page http://cxc.harvard.edu/proposer/maxexpo.html.
The grading scheme for constrained observations is shown in Table 5.1. Cycle quotas are also listed; ~80% of these will be allocated to the Chandra Peer Review.
Note that a constrained observation that has more than one constraint grade according to Table 5.1 will be given the most restrictive grade. Specifically:
Constraints should be specified to achieve the science not the grade. It is noteworthy that, over the past several cycles, the Easy category had the highest oversubscription factor while the
Average category had the lowest.
The RPS provides a tool which, given the entered target parameters, generates an estimate of the constraint class of each target and the “slew tax” (pointing overhead) which will be charged at the peer review. Final constraint classifications will be determined by the CXC after the proposal deadline, taking into account all declared constraints, including those that are specified in the remarks.
Observers wishing to assess the classification of their observations in complex, ambiguous or highly constrained cases should contact the CXC HelpDesk (Section 6.1.2), allowing adequate time before the proposal deadline for a response to be made.
Table 5.1. Grading Scheme for Constrained Observations
|
Constraint |
Parameter |
Easy |
Average |
Difficult |
|
Uninterrupted (ksec) |
Duration |
<30 |
30-40 |
>40 |
|
Coordinated (days) |
Window |
- |
>3 |
<3 |
|
Roll (days)1 |
Window |
>21 |
3-21 |
<3 |
|
Time Window (days) |
Window |
>21 |
3-21 |
<3 |
|
Phase Interval (days) |
Period |
<20 |
20-60 |
>60 |
|
Monitor Interval |
Note (2) |
>5 |
2-5 |
<2 |
|
Group |
Note (3) |
>10 |
4-10 |
<4 |
|
|
Cycle Quota4 |
46 |
36 |
21 |
Notes:
The proposer should include in his or her scientific justification a list of all other observing facilities being used for the proposed research, in addition to those being requested in this proposal. These facilities should be discussed whether or not their use results in a time constraint on the Chandra observations. Note that, apart from NRAO, coordination with ground-based observations may only be listed as a preference.
The PI must provide a list of all previous approved Chandra Observing, Archival Research, Theory/Modeling, or GTO programs for which they were PI, along with a brief status of the program(s) and resulting publications (1 page maximum, uploaded separately, see Table 5.2). Omit this page if there are no such programs.
The CXC seeks to track Chandra-related publications for the benefit of users of the Chandra Data Archive, for proposal reviewers, and for maintaining general Chandra bibliographic metrics. We encourage all users to provide material within their publications to facilitate this tracking. Authors should include wherever relevant (1) a DataSet Identifier for each ObsId; (2) Chandra grant number(s); and (3) the Chandra facility keyword ("CXO"). Details are described at http://cxc.harvard.edu/cdo/scipubs.html.
The PI has the option to include a one page CV and bibliography.
Observers with science goals that could be enhanced by having observations carried out in particular time windows, roll ranges, phase ranges, or monitoring intervals, are permitted to request these as preferences rather than requiring hard constraints. Preferences are not counted against the limited amount of constrained time, but can only be requested by formal specification on the RPS forms, not through requests after a proposal is accepted. Preferences are met on a best-effort basis. Specifically, when the Chandra long-term schedule is generated, attempts will be made to meet all preferences that do not conflict with approved constrained observations and do not violate spacecraft constraints or guidelines. Preferences that force targets to be observed at unfavorable pitch angles are unlikely to be met. Proposers should use the PRoVis tool, available on the CXC website, to confirm that a constraint (or monitoring sequence) which they are considering does not require observations at pitch angles and with durations that are not feasible (as described in Section 2.3). Once placed in the LTS, attempts will be made to accomplish the preferences, but this is not guaranteed; changes required to meet TOOs or to balance spacecraft considerations may result in changes to the observing plan leaving preferences unmet.
Note: Any constraint that is required for the science goals of a proposal MUST be specified as a constraint in RPS (Section 5.2.8).
All proposal text must be in English. Because of the large number of proposals anticipated in response to this CfP, there will be strict page limits as shown in Table 5.2. Excess pages will be removed from proposals before the peer review. All information required to evaluate the proposal must be included within the proposal page limits. Reference to published papers or web-based material may be used for supporting material only. The section including the scientific justification and technical feasibility is limited to six pages for observing proposals that are classified as Large Projects (designated as such by the PI and requesting 300-999 ksec) or as Joint Projects (CXO/HST, CXO/NOAO, CXO/XMM, CXO/NRAO, CXO/Suzaku, CXO/ Spitzer, CXO/Swift), to seven pages for X-ray Visionary Projects (requesting 1-5 Msec), and to four pages in all other cases including proposals for a TOO, Archival Research, and Theoretical/Modeling Research. For purposes of judging the length of the electronic proposal, the following guidelines apply:
Proposers are encouraged to use the LaTex template provided at the CXC website, (http://cxc.harvard.edu/proposer/) that conforms to these requirements. Please insure also that the LaTex is properly converted to PDF (see http://cxc.harvard.edu/proposer/generatePDF.html).
Proposals that exceed the page limit will have all excess pages removed. Proposals that violate the font or margin sizes will be rejected. Submitted science justification PDF files may not exceed 10 Mbytes in size, or they will be automatically rejected with an error message.
Table 5.2. Proposal Content and Page Limit
| Section (Note 1) | Page Limit | Comments |
|---|---|---|
| Cover Page Form | 1 | No other cover needed |
| General Form | 1 | No other cover needed |
Scientific Justification and Technical
Feasibility
| Including text, figures, charts, tables, references, and budget narrative (for archival research and theory). | |
| 4 | ||
| 6 | ||
| 7 | ||
| Target Forms | As Needed | Not required for Archival Research of Theory/Modeling proposals |
| Previous Chandra Programs | 1 | List of previous programs of PI and Observing Investigator (if any) including publications (Note 2) |
| PI's CV/Bibliography (optional) | 1 | Emphasis should be on relevant experience and publications |
Notes:
Proposal preparation and simulation tools are available on the World Wide Web as listed in Table 1.3. The proposer is urged to make use of these tools well before the deadline for proposal submission.
All Stage 1 proposals are required to be submitted electronically according to the instructions given below and on the CXC website (http://cxc.harvard.edu/cgi-bin/RPS/Chandra/RPS.pl). The file, including the science justification and previous Chandra program list (and, optionally, a CV), must be in PDF format. Electronic submission facilitates efficient proposal processing and reduces the likelihood of transcription error in the various databases. Proposers who do not have access to electronic communications should call the Chandra Director’s Office, (617) 495-7268.
Stage 1 proposals must be submitted electronically by either of two methods, both of which make use of the Remote Proposal System (RPS) software. More detailed information concerning the Chandra RPS system may be found on the CXC website (http://cxc.harvard.edu/cgi-bin/RPS/Chandra/RPS.pl).
The proposer may access this system either through the World Wide Web (WWW) or by email as follows:
<BEGIN>
<OPTION=HELP>
<END>
in the body. A proposer may convert from the web-based to the email version using the RPS email button. When using the email version, separate PDF files for the science justification, the previous Chandra program list (if required), and CV (optional) should be submitted using ftp to cxc.harvard.edu following the instructions provided by RPS.
Independent of interface, the process will, at a minimum, involve the following steps for all proposals:
If a mistake is discovered before the deadline, please go through the submit process as if you had not submitted before, resubmitting both the form and science justification, and entering the number of the proposal being replaced. The proposal is scanned to confirm that it is a resubmission. Proposals for which resubmission cannot be confirmed are flagged for the attention of a CXC staff member. The proposal with the most recent date and time is considered as the “final” proposal.
It is possible to correct minor errors in forms after the proposal deadline, especially if the item is critical to the success of the potential observation (e.g., incorrect coordinates). Please inform the CXC (via the HelpDesk, http://cxc.harvard.edu/helpdesk/) as soon as possible after the mistake is discovered.
Late changes in the Science Justification are not allowed. However, some typographical or numerical errors can be misleading, and corrections of such can be sent to the CXC in a letter or email of explanation. If appropriate, this letter will be included in material sent to the peer review. Note that a long list of corrections to a careless submission cannot be accepted as this would be considered de facto as a late proposal submission.
The default distribution of proposals to the peer reviewers will be electronic in PDF format. Black and white hardcopies will be provided only at the specific request of individual reviewers. It is therefore no longer necessary to submit multiple hardcopies that include color figures. However, since color figures do not always reproduce well in black and white, if the PI so wishes, 10 color hardcopies may be submitted to the CXC by the proposal deadline for distribution to reviewers who request hardcopies.
