How to Query HEASARC VO-enabled Services

The Cone Search service allows a user to specify coordinates in RA/Dec and a search radius. The result is a VOTable formatted XML that contains metadata on the target in question. If you are interested in a particular survey and you have the survey's shortname, you can specify a URL containing RA,Dec,survey name, and radius. The response is a VOTable formatted XML with RA and Dec columns. To submit a Cone Search query do the following:

Step 1: Go to the STScI registry.

Step 2: To search for HEASARC Cone services,select 'Id' from the 'All Fields' drop down and enter "nasa.heasarc" in the search box.

Step 3: Now you will see a list of resources provided at the HEASARC.

Step 4: Click on the 'Capability Type' drop down option. You will get a list of the various capabilities at the HEASARC including a 'Simple Cone Search' link. Click on this link to see a list of just the Cone services at the HEASARC.

Step 5: Now select, for example, the AAVSO survey. You will go to a form containing data on the survey you selected.

Step 6: Under 'Available Service Interfaces' click on 'Simple Cone Search'. You will see a serviceURL under 'Available endpoints for the standard interface'. Copy this service URL and enter it in a new window.

Step 7: Append the coordinates and search radius by entering RA, Dec and SR after the Service URL. The format should be "RA=xx&DEC=yy&SR=zz" where xx,yy,and zz are the RA,Dec,and search radius respectively. Run your query in a browser. You will get a VOTable containing data on targets inside the search radius.

HEASARC SIAP Services

The STScI registry provides a means to directly access the HEASARC SkyView SIAP services. The response is an image of a region of sky. The following instructions describe how to get the base URL for a SkyView survey and how to obtain an image. Follow steps 1-3 for retrieving a Cone Search URL and then proceed with the following steps:

Step 4: Now click on 'Simple Image Access Protocol' in the 'Capability Type' dropdown. You will get a list of various surveys that SkyView can browse for you. Now let's choose a survey. For this example, we will use 'AKARI'. Click on the 'AKARI' link and you will see a page containing information on the survey.

Step 6: Enter the URL in a new window. Append the coordinates and search radius after the service URL by entering "POS=xx,yy&SIZE=zz" where xx, yy, and zz are the RA,Dec, and search radius respectively. Now run your query.

Step 7: You will get a VOTable containing a number of image URLs.

HEASARC SSA Services

Step 4: Now use the 'Capability Type' dropdown and select 'Simple Spectral Access' to get a list of observations. For this example we will select 'Chandra Observations'. Click on the 'Chandra Observations' link.

Step 7: You will get a VOTable containing FITS data URLs if the positional information you used covers an area of sky that was observed.

Example:
You are interested in Chandra data for 3c273. Follow the steps above, select "Chandra Observations", cut and paste the SSA URL in a browser and append the coordinates for 3c273. In this case, a complete URL might look like:

https://heasarc.gsfc.nasa.gov/xamin/vo/ssa?table=chanmaster&POS=187.27,2.05&SIZE=.01&REQUEST=queryData

You will get a VOTable that contains a number of FITS URLs.

E.g.
http://heasarc.gsfc.nasa.gov/FTP/chandra/data/science/ao08/cat7/7364/primary/acisf07364N004_pha2.fits.gz

You can then download your FITS file from the above URL.

HEASARC TAP Services

The STScI registry provides a means to directly access HEASARC TAP services. The following instructions describe how to get the base URL for a HEASARC TAP service. Follow steps 1-3 for the Cone Search above and then proceed with the following steps:

Step 4: Now use the 'Capability Type' dropdown and select 'Table Access Protocol'. You will get a list of various HEASARC catalogs that are TAP-enabled. For this example we will use the 'AAVSO International Variable Star Index' catalog. Click on the AAVSO catalog link.

Step 5: You will now see a page containing information on the resource. Under 'Available Service Interfaces', copy the URL under 'Table Access Protocol-Auxiliary Service'.

Step 6: Enter the URL in a new window. You can now append for example, the '/capabilities' keyword to get a list of the capabilies for this service.

Example:
You want to find the TAP URL for the HEABIB catalog. After querying the registry you find the HEABIB catalog info at:

http://vao.stsci.edu/directory/getRecord.aspx?id=ivo://nasa.heasarc/heabib

The TAP URL for HEABIB is listed under 'Available Service Interfaces' and is:

https://heasarc.gsfc.nasa.gov/xamin/vo/tap

You can now append '/tables' to this URL to get the tableset view. You can also choose from a number of different queries. For other types of queries that can be performed please refer to the TAP V 1.0 Recommendation.