Search Basics

ADS’s one box search form supports both fielded and unfielded queries. Unfielded queries without search terms will search the metadata of the publications, including author, publication year, title, abstract, identifiers, and bibstem, which may not produce the expected results. For instance, if you are searching for papers by the author Marc Mars, you want to search for author:“Mars, Marc” instead of Marc Mars to make sure that you don’t return papers that simply have the words “Marc” and “Mars” somewhere in the article metadata.

Fielded Searches

Above the search box we supply shortcuts to frequently used search fields. Simply click on the field that you wish to search and enter your search term in the provided location (generally between the supplied quotation marks). Alternatively, if you start entering the name of a field an autocomplete feature will suggest a list of possible search fields. You may string several search terms or use the filters provided with your results to help narrow the search selection. For instance if you want to find articles published between 1980 and 1990 by John Huchra, you can use:

author:"Huchra, John" year:1980-1990

To get you started, here is a list of search examples for commonly used fields:

The rest of this page goes over the search syntax and fields indexed in our database.

Combining Search Terms to Make a Compound Query

You can string together any number of search terms to develop a query. By default search terms will be combined using AND as the default boolean operator, but this can be changed by explicitly specifying OR beween them. Similarly one can exclude a term by prepending a “-“ sign to it (or using the boolean “NOT”). Multiple search words or phrases may be grouped in a fielded query by enclosing them in parenthesis. Some examples:

Operator precedence in multi-part searches

Searches involving only two search terms, as shown above, are straightforward to parse. However, for searches with multiple search terms and multiple operators, understanding how operators take precendence over each other is important. For the most control, use parentheses around terms and operators that should be executed first. Otherwise, operators follow these general rules:

• AND, OR, and NOT are set operators, operating on the search terms on either side. AND takes the intersection of the result set of the two search terms, OR takes the union, and NOT takes the difference. NOT takes precendence over AND, which takes precendence over OR.
• The default AND (i.e., not typing out AND but using just a blank space between the two terms, as in the first example above) has lower precedence than any of the Boolean operators above.
• The negative sign (-) is read as “prohibit”; results containing this term are completely excluded. In multi-part queries, its behavior can differ from that of NOT, because of the precedence rules.

For a more heavy handed exploration of the search syntax, feel free to visit the search parser details page.

Wildcards, Proximity, and Regular expression search

Synonyms and Acronyms

By default most search terms in ADS are expanded by adding a list of words which are synonyms of the search term. So for example, a search of “star” in the title field will be expanded to include words such as “stars,” “stellar,” “starry,” “starlike,” and so on. (Notice that this often includes words in foreign languages such as “etoile,” “stern,” and “stella”). While this feature improves recall, it sometimes compromises the precision of the results. Our search engine allows one to turn off the synonym expansion feature by simply prepending an “=” sign in front of the search term.

Our search engine also identifies acronyms during indexing and searching (defined as words consisting entirely of uppercase characters). A search for an uppercase word will only match documents which contain that acronym, whereas a search for a lowercase word will match documents which contain any variation of the word, irregardless of its case. Acronyms can themselves have synonyms (for example “ADS” and “Astrophysics Data System” are synonyms), so one should be aware that there is an interaction between case-sensitiveness and synonym expansion. The examples below illustrate these effects:

Author Searches

Synoym expansion also applies to author names, which provide a way to account for changes in a person’s name and/or different spellings due to transliterations. In addition to this, the default author search in ADS is “greedy” in the sense that it will return all documents in which an author signature may match the input search string. This allows, for instance, to have an author search for “Huchra, John” to return papers where the author name appears as “Huchra, John” or “Huchra, J.” By prepending the “=” character to the author search one can disable this feature (as well as any additional synonym expansion) and require an exact match on the author name. Some examples:

As a general rule we recommend to use the full name of the person for author searches since as can be seen above the matching rules in ADS are designed to find the maximal set of records consistent with the author specification given by the user. Rather than disabling the name-variation algorithm described above, we recommend performing refinement of search results via the user interface filters for author names as described in the “Filter your search” section.

The logic behind the author search is rather complicated, if you would like to learn more, visit the advanced author search page.

Affiliation Searches

Affiliations in ADS have been indexed in several different search fields, with the intention of allowing multiple use cases. We have currently assigned affiliation identifiers allowing for parent/child relationships, such as an academic department within a university. Note that a child may have multiple parents, but we restrict a child from having children of its own. The list of recognized institutions is available from our Canonical Affiliation repository on Github.

For a breakdown to department level:

• Use the “Institutions” filter in the left panel of search results
• Use parent/child syntax as defined in our list of Canonical Affiliations linked above (e.g. inst:“UCLA/IGPP”)

Users are reminded that while affiliation information is largely complete for recent refereed literature, not all records contain an affiliation; therefore, searching by affiliation alone will inherently be incomplete. We strongly recommend combining affiliation searches with author searches for best results.

Astronomical Objects and Position Search

The query modifier object: in fielded searches allows users to search the literature for bibliographic records that have been tagged with astronomical objects by SIMBAD and NED, or for a specified position on the sky (“cone search”). The cone search also makes use of services offered by SIMBAD and NED.

Queries for astronomical objects via object: queries return publications that have been tagged with the canonical names for these objects. This tagging has been done by the SIMBAD and NED teams. Additionally, the object names (as specified in the query) are also used in an ADS query against abstracts, titles and keywords in the astronomy collection (with synonym replacement switched off). The result set is a combination of all these matches. Object queries that target just one service (e.g. SIMBAD) are not currently supported. The data facet can be used to filter the results set.

The syntax for cone searches is:

  object:"RA ±Dec:radius"

where RA and Dec are right ascention and declination J2000 positions, expressed in decimal degrees or in sexagesimal notation (hours minutes seconds and degrees arcmin and arcsec). The plus or minus sign before the declination is mandatory. The search radius may be given in arcmin, decimal or sexagesimal degrees (The default search radius is 2’, and the maximum is 60’). Examples:

• A 10’ radius may be written as 0.1667 or 0 10
• The following 3 notations are equivalent:
  1. 05h23m34.6s -69d45m22s
  2. 05 23 34.6 -69 45 22
  3. 80.894167 -69.756111

Searching for publications tagged with objects returned by the coordinates in the example above, with a search radius of 10’ is done as follows:

object:"05h23m34.6s -69d45m22s:0.1667"

The equivalent of (see 2007ASPC..382..495K)

http://adsabs.harvard.edu/cgi-bin/abs_connect?data_type=VOTABLE&DEC=60&RA=16&SR=.1

is the search object:"16 +60:0.1", followed by exporting the results in the VOTable export format. Currently there is no equivalent of the ADS Classic URL shown above.

Available Fields

This is a list of fields currently recognized by the ADS search engine and the preferred search format - go to comprehensive list of fields if not saturated yet:

(*) See below for details on these filters. In most cases, filtering of results based on these fields is available in the user interface.

Properties

The “properties” search field allows one to restrict the search results to papers which belong to a particular class. The allowed properties currently include:

Bibliographic Groups

The “bibgroup” search field allows restriction of the search results to one of the ADS bibliographic groups. These groups are curated by a number of librarians and archivists who maintain either institutional or “telescope” bibliographies on behalf of their projects. Here is a partial list. For more information on the criteria behind the curation of these groups, please see the link above.

The list of current Institutional bibgroups is: ARI, CfA, CFHT, Leiden, USNO

The list of current Telescope bibgroups is: ALMA, CXC, ESO, Gemini, Herschel, HST, ISO, IUE, JCMT, Keck, Magellan, NOIRLab, NRAO, ROSAT, SDO, SMA, Spitzer, Subaru, Swift, UKIRT, XMM

Data Links

The “data” search field can be used to select papers which have data links associated to them. The list of archives which ADS links to can be seen under the “Data” filter selection. To generate a list of all records which have data links one can issue a simple wildcard query: data:* . Using the data search field allows one to focus on data-rich papers, for example:

data:(CXO OR XMM) AND data:HST

Finds multi-wavelength papers which have observations both in the X-ray spectrum (from Chandra or XMM) and in the optical (HST). Of course additional search terms can be used to further refine the selection criteria.

Document Type

Records in ADS are assigned a document type which is indexed in the “doctype” search field, the contents of which are an extension of the BibTeX entry types. Currently these are the document types indexed by ADS: