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The CXC has extensive on-line resources for Chandra proposers and a suite of software tools for common proposal-related tasks. All proposal-related material can be found at http://cxc.harvard.edu/proposer/.

6.1     On-line Resources

6.1.1     The Proposers’ Observatory Guide (POG)

The main reference document for Chandra operation and instrumentation is the Chandra Proposers’ Observatory Guide. The POG is available from the CXC website (http://cxc.harvard.edu/proposer/POG/). Additional information can be found at the “Instruments and Calibration” (http://cxc.harvard.edu/cal/) link on the CXC web page.

A hardcopy version of the POG is available upon request to the CXC HelpDesk (http://cxc.harvard.edu/helpdesk/).

6.1.2     The HelpDesk

The CXC uses commercial Helpdesk software to track users’ requests and problems. Click on “Log into the CXC HelpDesk”, and the HelpDesk login box will appear. Enter a user name (we suggest first and middle initial followed by last name, but any unique string will be okay) and password and press enter/return to log in. Once you have logged in, you can send a query (or “ticket”) by clicking on the “Open a New Ticket”. New users will be asked to enter more information (this only needs to be done once). HelpDesk also allows you to search previous tickets that are not private. More detailed information is given on the interface. Users can also email the CXC HelpDesk: cxchelp@head.cfa.harvard.edu.

In the last few days before and after the proposal deadline, we activate a dedicated email address for problems with proposal submission. This address should be used for proposal submission purposes only and is not active for most of the year. This dedicated email address helps the CDO to deal more efficiently with the very large volume of correspondence we receive around the proposal deadline. Dates for which the address is switched on will be posted on the proposer page at the CXC website. The proposal help email address is: prophelp@head.cfa.harvard.edu.

Proposal queries submitted to the HelpDesk will always be answered.

6.1.3     Searching the Chandra Archives and Downloading Data

ChaSeR (Search and Retrieval from the Chandra Data Archive) allows a user to check what observations have been made, the status of the observations (observed, publicly released, etc.), and ultimately to select data products and retrieve them. The web version of ChaSeR can be accessed at http://cda.harvard.edu/chaser/ .

There is also a downloadable version of ChaSeR that has somewhat more sophisticated search capabilities than the web version. ChaSeR is available from the Chandra Data Archive (http://cxc.cfa.harvard.edu/cda/chaser.html).

ChaSeR includes a precession tool and provides quick access to images. ChaSeR is extensively documented on the archive pages of the CXC website. In particular, there are detailed instructions for installation on many systems and a useful FAQ page. The user is referred to these sources for installation instructions as well as usage tips, updates, and more complete documentation.

The Chandra Data Archive Footprint Service provides a visual web interface to all public Chandra observations as well as the observational data used for the Chandra Source Catalog. The instrumental sky coverage is superimposed on an image from the Digital Sky Survey. This tool also provides access to Chandra images and a seamless interface to WebChaSeR for downloading data. The CDA Footprint service is available from:

http://cxc.harvard.edu/cda/footprint/cdaview.html

The Bibliography web interface allows simultaneous searching of the archive and of the papers published on Chandra observations. It is available from

http://cxc.harvard.edu/cgi-gen/cda/bibliography.

Detailed target lists by cycle and a complete list of approved Large and Very Large Projects can be found at

http://cxc.harvard.edu/target_lists/index.html.

An additional tool of interest is the processing status tool, which provides comprehensive information about the processing of each observation. The processing status tool can be accessed via WebChaser. The tool can also be accessed from http://cxc.harvard.edu/soft/op/op_pst.html.

6.1.4     Instrument Response Functions

Instrument response functions (RMFs and ARFs) for simulating spectra within Sherpa and XSPEC can be found on the proposer page (http://cxc.harvard.edu/proposer/) and the Calibration Database (CALDB) page (http://cxc.harvard.edu/caldb/). These responses should be used for proposal preparation only; they should NOT be used for data analysis because they are not accurate for the date of a specific observation.

6.2     Proposal Preparation Software

The CXC provides several software tools to aid in proposal preparation.

6.2.1     Precess, Colden, Dates, ObsVis, PRoVis, PIMMS, and Effective Area and PSF Viewers

These tools perform the following functions:

• Precess is an interactive astronomical coordinate conversion program. It allows precession of equatorial coordinates and conversion between equatorial, ecliptic, galactic, and supergalactic coordinates.


• Colden is an interactive program to evaluate the neutral hydrogen column density at a given direction on the sky. Colden accesses two databases: the Bell survey (Stark et al 1992 ApJS 79. 77) and the Dickey & Lockman 1990 (ARA&A, 28, p.215) compilation of Bell and other surveys for all-sky coverage.


• Dates is an interactive calendar and time conversion tool.


• ObsVis is a tool to aid observation planning allowing inspection of instrument fields-of-view (FOVs). It will display instrument FOVs on a Digital Sky Survey or user-loaded image, mark the locations of sources from various X-ray catalogs and provides other functionality such as manipulation of multiple fields-of-view for planning of grids of observations.


• PRoVis is a web-based tool which allows interactive plotting of observatory roll angle, pitch angle and target visibility for use in checking observation feasibility. This software includes indication of ranges of pitch angle with restricted exposure times and dynamic interaction with the display.


• PIMMS (Portable Interactive Multi-Mission Simulator) was developed at NASA-GSFC by Dr. K. Mukai. [We thank Dr. Mukai for making some changes to the code for Chandra.] PIMMS allows the user to convert between source fluxes and count rates for different missions. PIMMS also uses simple spectral models (blackbody, bremsstrahlung, power, Raymond-Smith) to calculate count rates or fluxes.


• Effective Area Viewer is a web-based tool that displays the on-axis Effective Area provided for proposal planning and allows comparison with versions from previous cycles.


• PSF Viewer is a web-based tool that displays the PSF (Point Spread Function) (see http://cxc.harvard.edu/cgi-bin/build_viewer.cgi?psf ).

All of these tools have web interfaces linked into the Proposer pages. Command-line (non-web) versions that have additional features are also available for several tools. For example, command line versions of Precess, Colden, Dates allow for a list of input parameters in a text file.

The command-line versions of these tools are distributed with CIAO (see Section 6.2.4). Chandra users with CIAO installed can run these routines in the same way as all other CIAO tools (CLI tool names: prop_colden, prop_dates, prop_precess, and obsvis). Standard CIAO helpfiles are available.

6.2.2     Software Helpfiles and Proposal Threads

Helpfiles for proposal-related software and proposal “Threads” are available from the CXC proposer site (http://cxc.harvard.edu/proposer/). Helpfiles are available over the web as HTML files, in PDF format, and as part of the CIAO “ahelp” system. Proposal Threads are modeled on CIAO threads and give step-by-step examples of how to perform feasibility calculations, fill in the RPS forms, and submit a proposal. They are intended primarily (but not exclusively) for less experienced Chandra users.

6.2.3     MARX

MARX is a suite of programs created by the MIT/CXC group and designed to enable the user to simulate the on-orbit performance of the Chandra X-ray Observatory. MARX provides a detailed ray-trace simulation of how Chandra responds to a variety of astrophysical sources and can generate standard FITS events files and images as output. It contains detailed models for the HRMA mirror system as well as the HETG and LETG gratings and all focal plane detectors. More detailed information, including the source code and documentation, is available from the MIT MARX Web Page (http://space.mit.edu/CXC/MARX/). MARX should be used to demonstrate the feasibility of challenging observations, for example resolving multiple or overlapping sources with unique spectra, HETG observations of extremely bright objects, or grating observations of extended sources.

6.2.4     CIAO

The Chandra Interactive Analysis of Observations (CIAO) package is an extensive suite of tools designed for Chandra data reduction. Although not designed specifically for proposal preparation, CIAO can be used to analyze simulated Chandra data (e.g. from MARX) and create simulated spectra. Full details can be found at http://cxc.harvard.edu/ciao/. Sherpa is an interactive spatial/spectral fitting package that forms part of CIAO. It can also be used for simple simulations of Chandra spectra.

6.2.5     XSPEC

XSPEC is the spectral analysis portion of the Xanadu X-ray data analysis package, developed and maintained at NASA-GSFC. XSPEC can be obtained from:

http://heasarc.gsfc.nasa.gov/docs/xanadu/xspec/index.html.

The spectral simulation portion of XSPEC can also be run on-line. WEBSPEC can be accessed from: http://heasarc.gsfc.nasa.gov/webspec/webspec.html