Chandra X-Ray Observatory

CDA - Data Literature Links

Data Analysis Links
CDA Status
  • The archive is fully functional.
Reprocessing Status
  • Reprocessing has been completed for
    • Phase I: 2005-11-13 to 2011-12-31
    • Phase II: 2000-01-30 to 2005-11-13
Current Software Releases
  • ASCDSVER: 10.1
  • CALDBVER: 4.5.9
What's New
Linking Papers with the Observational Data They Present

As of January 2005, the publications managed by the AAS provide authors with a mechanism that allows them to make links between their articles and the observational data that is presented in them. We would like to urge our users to take full advantage of this opportunity to incorporate this linkage in their future papers.

As you may be aware, the Chandra Data Archive has been in the forefront of creating those links, making it possible for our users to jump from the archive browser to published articles - and for readers of those articles to inspect the data that they present. In addition, our bibliography interface provides a browsing tool for the Chandra-related literature and associated observations. This service has not come for free. It has required a substantial resource investment on the part of the Archive Operations Group. We are very happy to make this investment since we believe it provides a valuable service to our users; but we welcome any initiative that would lessen the burden - and this appears to be one of them.


The CIAO tool list_datasetid will examine the headers of a set of files and will provide a list of LaTeX dataset identifier macros to include in AAS manuscripts. The CIAO help pages provide complete details and examples for using the tool.


See also the AAS What's New in AASTeX page.

When preparing your AASTeX manuscript, you may include (multiple) \dataset macros that establish the link to the observations used in the paper. The syntax is:

      \dataset [<DataSetIdentifier>] {<AnchorText>}

where AnchorText is what is printed or, in the electronic version, the string that contains the link. The DataSetIdentifier is, for individual Chandra observations of the form:


where <ObsId> is the five-digit (including leading zeroes) Observation Id. For instance, for ObsId 5285 the Dataset Id macro would read:

      \dataset [ADS/Sa.CXO#obs/05285] {Chandra ObsId 5285}

A simplified macro syntax is also allowed where the journal editor determines the anchor text. The string in square brackets is omitted and the DataSetIdentifier is put in the curly brackets:

      \dataset {<DataSetIdentifier>}

Note that in this case the hash character (#) needs to be escaped:

      \dataset {ADS/Sa.CXO\#obs/05285}

If you are ever uncertain of the exact DataSetIdentifier string, you will find it in the header of the distributed FITS files (at least, the files created since May 2004) as the value of the keyword :

      DS_IDENT= 'ADS/Sa.CXO#obs/05285' / dataset identifier

The convention allows in principle for multiple Dataset keywords: DS_IDiii, where iii is a number between 001 and 999.

There may be multiple dataset macros in a manuscript, not only pointing to different missions, but also to more than one observation from a single mission. At some point this becomes unwieldy and we will allow users to request the assignment of customized DataSetIdentifiers for large sets (more than a dozen) of observations. The existing custom Identifiers are published here.

New custom Identifiers may be requested though our Special Request Form.

Finally, there is a webtool that allows you to verify or find valid DataSetIdentifiers.

Chandra Source Catalog

The DatasetIdentifier for the Chandra Source Catalog is:


What Are the Benefits?

For you, as author, it may be a little extra work, but it will ensure that archive browsers will have access to your paper - and that readers of your paper can easily find the data you used. The linkage will be error-free: not only does it save us work, but it also takes the guesswork (on our part) out of the equation, since you know exactly which observations you used. Actually, it is probably less work when you are writing the paper than several months later when we may be bugging you about it. In addition, it will make it possible to create the links from your preprint, if you upload the file to astro-ph.

How Will It Work?

When a AAS journal detects a \dataset macro in your manuscript, it will verify the validity of the DataSetIdentifier through a verification service that the ADS has set up in collaboration with the participating data centers. When the paper is entered into the ADS's database, the ADS will harvest the link between the paper and the dataset and keep it in its linking database. The links are, in turn, harvested by the data centers (CDA, in this case) to update their bibliography databases. Similarly, the ADS will harvest additional article links that the data centers provide.

Custom Dataset Identifiers

A list of existing Custom DataSetIdentifiers is available for checking and perusal.

This page maintained by the Chandra Data Archive (

Last modified: 2010-12-22

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