Accessing the HEASARC Registry

One convenient way to find HEASARC resources is through one of the VO searchable registries. On this page we demonstrate using the ST ScI registry. Other registries have similar capabilities.

HEASARC Cone Search 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 file with RA and Dec columns. To submit a Cone Search query do the following:

Step 1: Go to the ST ScI registry.

Step 2: To query the HEASARC enter "HEASARC" in the search box.

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

Step 4: Now click on Cone. You will get a listing of various surveys for which a Cone Search capability exists.

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

Step 6: Cut and paste the URL under "Service URL". Enter the URL in a new window.

Step 7: Append the coordinates and search radius by entering RA, Dec and SR after the Service URL. Format should be "RA=xx&DEC=xx&SR=xx" where xx is the value in decimal degrees for RA, Dec, and SR.

Step 8: You will get a VOTable in return containing data on targets inside the search radius.

Example:

You want to use the Abell Clusters of Galaxies catalog to gather some data on M57. Follow steps 1-4 above and then select "Abell Clusters". You will see a form containing data on the catalog. Find the "Service URL" link and cut and paste this link into the address box of a new window. In this case the link is:

http://heasarc.gsfc.nasa.gov/cgi-bin/vo/cone/coneGet.pl?table=abell&

To the above URL append "RA=xx&DEC=xx&SR=xx" with values for RA,Dec and SR. The RA,and Dec in decimal degrees for M57 in J2000 are: RA=283.39,Dec=33.02 A Cone Search with SR=13 might therefore look like:

http://heasarc.gsfc.nasa.gov/cgi-bin/vo/cone/coneGet.pl?table=abell&RA=283.39&DEC=33.02&SR=13

You will get a VOTable in return containing data for targets in the search radius.

HEASARC SIAP Services

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

Step 4: Now click on SIAP (Simple Image Access Protocol). You will get a listing of various surveys that SkyView can browse for you.

Step 5: Now pick a survey. You will see a page containing information on the survey.

Step 6: Cut and paste the URL under "ServiceURL". Enter the URL in a new window. Append the coordinates and search radius by entering "POS=RA,Dec&SIZE=SR" after the Service URL.

Step 7: You will get a VOTable returned containing a URL that points to your image.

Example:

Your are interested in SFD IR and Dustmap Surveys for M20. Follow steps 1-4 above and then select "SFD IR and Dust Map Surveys". You will see a form containing data on the survey. Find the "Service URL" link and cut and paste this link into the address box of a new window. In this case the link is:

http://skyview.gsfc.nasa.gov/cgi-bin/vo/sia.pl?survey=sfd&

Now append the coordinates. The syntax is "POS=RA,DEC&SIZE=SR" where SR is the radius of search. For M20, the RA and Dec in decimal degrees in J2000 are: RA=270.67 and Dec=-22.97 A complete query might look something like:

http://skyview.gsfc.nasa.gov/cgi-bin/vo/sia.pl?survey=sfd&POS=270.67,-22.97&SIZE=3

You will get in return a VOTable that contains a URL. The URL for the query above is:

http://skyview.gsfc.nasa.gov/cgi-bin/pskcall?SURVEY=SFD%20100%20micron&VCOORD=270.67%2C-22.97&SFACTR=3&RETURN=GIF

Enter the above URL to get the image.

Last modified: Wednesday, 21-Jun-2006 16:14:44 EDT