Various Access Methods to the Abstracts in the Astrophysics Data System

G. Eichhorn, A. Accomazzi, C. S. Grant, M. J. Kurtz, S. S. Murray

Smithsonian Astrophysical Observatory, 60 Garden Street, Cambridge, MA 02138, USA

Abstract:

1. Introduction

The Astrophysics Data System (ADS) (Eichhorn et al. 1995) provides access to astronomical literature abstracts, articles, and data. In this article various access methods to the ADS Abstract Service (Accomazzi et al. 1995) are described. The ADS now provides access to over 750,000 abstracts and over 15,000 articles. All this information can be accessed in several different ways.

2. Forms Access

The most common access is through a World Wide Web form (Figure 1).

  
Figure 1: Search Criteria Fields.
Figure 1: PS 97 Kb

This form allows the user to specify Search Criteria, Filters that restrict the returned references in several ways, and Settings to modify the logic of the search engine (Kurtz et al. 1993).

As Search Criteria the user can specify author names, object names, keywords, title words and abstract text words. These fields are combined as specified in the Settings to perform the search of the database. The returned references are then filtered according to the criteria specified in the Filters section of the query form. Filtering can be done by publication date, entry date of the reference in our database, minimum score, publications in which the article appears, and data items that are available for the reference. For each retrieved reference, the list of authors, the title, and the bibliographic code (Schmitz et al. 1995), the publication date, the score (showing how well the reference fits the query), and links to the available data (e.g., abstracts, full articles, tabular or image data) are returned.

3. Direct Access

Besides the normal user access by form, the abstracts and articles can be made accessible directly via an HTML hyperlink. Access through such a hyperlink will directly display the referenced abstract or article. The URL for abstracts is:

http://adsabs.harvard.edu/cgi-bin/bib_query?parameters

The parameters can be the following:

1. A bibliographic code (see above). Bibliographic codes can be constructed from the reference information automatically (see Schmitz et al. 1995).

2. A list of parameters of the form name=value concatenated with ``&''. Valid parameters are:

   bibcode= (mandatory) bibliographic code of the reference

   db_key= database from which to retrieve the reference (AST, INST, PHY)

   type= where to return data to (SCREENVIEW, PRINTER, FILE)

   data_type= what to return (HTML, PLAINTEXT, BIBTEX, PORTABLE)

To verify that a bibliographic code has an abstract, a verification utility is available.

Full articles can be accessed directly in similar fashion.

4. Access from a Perl Script

A third access method is through Perl scripts. This allows a programmer access to the ADS abstracts either directly via bibliographic codes or through the ADS search engine by specifying search criteria. The information is returned in Perl arrays. They contain all the fields available in the returned abstracts. These data can be included in customized results pages or integrated into other pages. A description of the usage of these Perl scripts is available. The Perl scripts can be downloaded from the same address. Please contact the ADS project if you plan to use this access method so we can keep you up-to-date on changes in these access routines.

5. Embedded Forms

Another way to access the ADS abstracts is to embed the ADS query form into another form, possibly filling in default information (like selection of a specified journal) in hidden fields. This allows other systems to include queries to ADS abstracts into forms that are customized to their specific application. This access however should be even more closely coordinated with the ADS since the parameters of the query form change as we implement new features. We try to maintain backward compatibility but that is not always possible. A description of the query fields is available.

6. E-mail Access

The access described in this section was implemented to allow access to our abstracts via e-mail, which in turn allows users to query the ADS database automatically on a regular basis to search for new information in our data. To make optimal use of this feature, the user would design a query form by trying out different query parameters until a satisfactory result is returned. This query form is then saved on the local machine with the ``Save Query Form'' button. This query form should include a filter for entry date that specifies a negative number in the entry day field. This negative number specifies how old entries in our database can be in order to be included in the query results. A --31 in the day field means that only references that have been entered in the last month will be returned. The query can be executed via e-mail by simply specifying:

mail adsquery.harvard.edu < /directory/form.html

where /directory/query_form.html is the filename of the saved form on the local machine. Executing this query automatically can be accomplished by putting the following entry in the users crontab file (on UNIX machines):

0 0 1 * * mail adsquery.harvard.edu < /directory/form.html > /dev/null

This entry will execute an e-mail query every first of the month and return all references that fulfill the query criteria in the saved form and have been entered in our database in the last month. The results are e-mailed to the user. This is a very convenient and effortless way of keeping up-to-date with the astronomical literature in a specific area.

7. Summary

The ADS Abstract Service can be accessed through the World Wide Web or via e-mail, by forms or via scripts. This allows great flexibility in how to retrieve information from the ADS Abstract Service and how to utilize the retrieved information. Please contact the author at gei@cfa.harvard.edu to get further information.

Acknowledgments:

This work is supported by NASA Grant NCCW-0024.

References:

Eichhorn, G., Murray, S. S., Kurtz, M. J., Accomazzi, A., & Grant, C. S. 1995, in Astronomical Data Analysis Software and Systems IV, ASP Conf. Ser., Vol. 77, eds. R. A. Shaw, H. E. Payne, & J. J. E. Hayes (San Francisco, ASP), p. 28

Kurtz, M. J., Karakashian, T., Stern, C. P., & Eichhorn, G. 1993, in Astronomical Data Analysis Software and Systems II, ASP Conf. Ser., Vol. 52, eds. R. J. Hanisch, R. J. V. Brissenden, & J. Barnes (San Francisco, ASP), p. 132

Schmitz, M., Helou, G., Dubois, P., LaGue, C., Madore, B., Corwin Jr., H. G., & Lesteven, S. 1995, in Information & On-line Data in Astronomy, eds. D. Egret & M. A. Albrecht (Kluwer Acad. Publ.)