5.1     Overview and Schedule of Process

Science proposal submission and review will be conducted in two stages to minimize the burden of proposal preparation.

• Stage 1: During the first stage, the scientific and technical merits of the proposed investigation (Archival Research and Theory/Modeling as well as new observations) will be reviewed, including the appropriateness of using Chandra to address the scientific objectives and the relevance of the investigation to furthering our understanding of high-energy astrophysical processes. Based upon the recommendation of the Stage 1 peer review (scientific and technical), the Selection Official (the CXC Director) will select a set of proposals for award of observing time (proposals for new observations) or award of support for analysis and/or interpretation of existing data (Archival Research and Theory/Modeling proposals).
• Stage 2: The PIs of those proposals selected in Stage 1 will then be invited to submit a cost proposal for the Stage 2 review (Chapter 8) and will also be given an opportunity to submit an Education and Public Outreach (EPO) proposal (Chapter 9). A subset of the Stage 1 science peer review panel will evaluate the cost proposals and provide a list of those recommended for selection to the Selection Official. A separate peer review panel will be convened to review the EPO proposals.

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 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 15 % of the total number of observations selected. Details of constraint classification and quotas are described in section 5.2.8

5.2     Stage 1 Research Proposal Details

5.2.1 Proposal Content

The Stage 1 proposal must include:

• Cover Page Form;
• General Form;
• Target Summary Form, if the proposal requires new observations;
• Scientific Justification and Technical Feasibility (as described below);
• Previous Chandra Programs listing (one page, described below); and
• CV/Bibliography for the PI (one-page, optional).

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, as well as for scheduling those observations that are selected for implementation. The forms must be completed in the requested format. Cost sections and EPO proposals 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 and EPO proposals will be considered as part of the Stage 2 process.

5.2.2 Cover Pages

Although a signature block is included on the General Form, institutional endorsements 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 list of selected targets and corresponding abstracts will be made public once the results have been announced.

5.2.3 Target Forms

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. The information in the RPS forms will take precedence over any contradictory/different information described in the proposal science justification. 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.

PIs should ensure that information on target forms is correct. Incorrect information will jeopardize the acceptance of a proposal.

 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/epoch J2000. 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 crosscheck. If 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, ((http://cxc.harvard.edu/helpdesk/) as soon as possible, to confirm the coordinates or 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. If a large number of targets are requested (more than 5), the email version of the RPS is the recommended method of preparing the forms.

5.2.4 Science Objectives

State clearly the scientific objectives, with relevant background and reference to previous work. 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. 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.

5.2.5 Technical Feasibility

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 of 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 for imaging the maximum number of ACIS CCDs that their core science allows.  Please see the Proposers’ Observatory Guide (POG, Section 6.20.2) concerning optional ACIS chips.

5.2.6 Archival Research and Theory/Modeling

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.

5.2.7 Joint Proposals

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 on 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).

5.2.8 Constrained 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 (see Section 2.3). Thus, proposers should carefully consider the impact of a request for a constrained observation and provide scientific 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 ObsVis 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 directed in section 2.3).

The grading scheme for constrained observations is shown in Table 5.1 Cycle quotas are also listed; ~80% of these will be available to the Chandra peer review.

Note that a constrained observation that has different grades according to Table 5.1 will be given the most restrictive grade. However, an observation that has many constraints will only be counted once towards the appropriate quota. Specifically:

1. If multiple observations of the same target are proposed (e.g., a sequence of coordinated observations, or a monitoring series), then each observation contributes separately to the allowed quota of observations in that difficulty class.
2. An observation constrained in multiple ways is counted in the highest (i.e. most difficult) category resulting from considering each constraint type separately.
3. In the case of long observations (>80 ksec), each 80 ksec increment or fraction thereof will count as a separate observation against the quotas allowed for the relevant category of difficulty.
4. Constrained grid observations will also be accounted in 80 ksec units for the purpose of counting constraints (Section 7.1).

Constraints should be specified to fit the science not the classification.  It is noteworthy that the Easy category had the highest oversubscription ratio in Cycle 9 (11:1) while the Average category was undersubscribed.

If observers wish to assess the classification of their observations in complex or ambiguous cases, please contact the CXC HelpDesk (section 6.1.2 of the CfP), allowing adequate time before the proposal deadline for a response to be made.

Table 5.1.     Grading Scheme for Constrained Observations

Constrain	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	(2)	>5	2-5	<2
Group	(3)	>10	4-10	<4
	Annual Quota (4)	45	35	20

(1) The constraint refers to the number of days at which a target can remain within the declared roll angle constraint. This can be estimated using the ObsVis tool (Web versions) available on the Proposer Webpage. Only nominal roll values should be used since off-nominal rolls have very brief dwell times.

(2) The dimensionless parameter for the monitoring interval constraint is: (INITIAL INTERVAL) * (FRACTIONAL TOLERANCE) / (TOTAL DURATION OF SINGLE OBSERVATION)

(3) The dimensionless parameter for Group Observations is: (TIME INTERVAL FOR THE GROUP) / (TOTAL DURATION OF OBSERVATIONS IN GROUP)

(4) Should a quota be unfilled at the Peer Review it may be combined with a quota at a lower difficulty level.

5.2.9 Other Observing Facilities Being Used for the Research

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.

5.2.10 Previous Chandra Programs

The PI and Observing Investigator (if any) must provide a list of all previous Chandra Observing, Archival Research, Theory/Modeling, or GTO programs in which they were involved along with the status of the program(s) and any resulting publications (1 page maximum, see Table 5.2).

5.2.11 PI/CV Bibliography

The PI has the option to include a one page CV and bibliography.

5.2.12 Observation Preferences

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 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 request observations that force targets to be observed at unfavorable pitch angles will not be met. Proposers should use the ObsVis 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.

5.2.13 Proposal Formats and Page Limits

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. Proposals that violate the font or margin regulations will be rejected. All information required to complete and understand 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 or Very Large Projects (designated as such by the PI and requesting at least 300 ksec or at least 1 Msec, respectively) or as Joint Projects (CXO/HST, CXO/NOAO, CXO/XMM, CXO/NRAO and CXO/RXTE), 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:

• Each side of a printed paper sheet containing text or illustration will count as one page;
• Text may be either single or double-spaced, but must use an easily read font having no more than 15 characters per inch (minimum 11 pt); and
• Each page must have at least 1-inch margins on all sides of a standard 8.5 x 11 inches (US-letter sized) sheet.

Proposers are encouraged to use the LaTex template provided at the CXC website, (http://cxc.harvard.edu/proposer/)  that conforms to these requirements.

Proposal format violations: Proposals that exceed the page limit will have all excess pages removed. Proposals that violate the font size will be rejected and returned to the PI.

Table 5.2.     Proposal Content and Page Limit

Notes:

a. The proposal forms may be accessed via the Remote Proposal System (RPS) software at http://cxc.harvard.edu/.

b. Those with a large number of prior programs may include minimal information but should include proposal number, PI, Observers, references (one per line).

5.2.14 Proposal Preparation Tools

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.

5.3     Proposal Submission Instructions

5.3.1 Electronic Submission Required

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.

5.3.2 Remote Proposal System (RPS)

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:

• The WWW version of the Chandra RPS provides a form-based interface. Access is linked to the Chandra home page at http://cxc.harvard.edu/ (select “Proposer” link [http://cxc.harvard.edu/proposer/]. Help files for each form and each input parameter are available as hypertext links, and the user has complete control over the entries.
• The interface to the email version of the Chandra RPS needs to be initiated by the proposer. Instructions may be obtained by sending an email message to: rps@head.cfa.harvard.edu with:

  <BEGIN>

  <OPTION=HELP>

  <END>

  in the body. In this case, the science justification PDF file should be submitted using ftp to cxc.harvard.edu following the instructions provided by RPS.
• The email interface is recommended for proposals including more than a few targets.
• Independent of interface, the process will, at a minimum, involve the following steps for all proposals:
• Preparing the Scientific Justification and Technical Feasibility, preparing the list of previous Chandra programs and (optionally) the PI CV/bibliography, including any figures, and converting the document to a single PDF file. Please be sure to print out the PDF file to ensure it is readable before submitting it;
• Providing the information for, and completing, the Cover Page and General Form. For proposals requiring new observations, the Target Form(s), including constraints and remarks where needed;
• Verifying that the information on the Cover Page Form, the General Form, and (as appropriate) the Target Form(s) is correct;
• Submitting the Cover Page Form, the General Form, and (as appropriate) the Target Form(s), following which RPS assigns a proposal number;
• Submitting the PDF file of the Science Justification and Technical Feasibility, list of previous programs (and optional CV), etc.; and
• Receiving an email acknowledging receipt of your proposal and notification of the proposal number and of any errors found via crosscheck of the target information with the SIMBAD and/or RASS catalog and with the Chandra Observation Catalog. For gratings observations this check will confirm/not the presence of an RASS source close to the target position.  Under the assumption that most gratings targets are RASS sources, this minimizes the chance of incorrect coordinates.
• Should an error in your coordinates or target list be found by the above check, your proposal should be corrected and re-submitted.

5.3.3 Help After Submitting: When You Have Discovered A Mistake

If the 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 member of the CXC. 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.

5.3.4 Color Figures

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, 10 color hardcopies may be submitted to the CXC, by the proposal deadline, for distribution to reviewers who request hardcopies if the PI so wishes.

5.3.5 EPO Proposals

Specific instructions for electronic submission of supplementary EPO proposals will be described in a separate CfP and will be posted on the CXC website.