Frequently Asked Questions (FAQs)

SearchingClassic Search TranslatorTransitioning from ClassicADS LibrariesORCIDDatabase CoverageOther


Q: Typing a fielded query for an author query (e.g. author:“huchra, j.” or author:“^huchra, j.”) or clicking on the search term dropdown leads to a lot of additional work over a similar search in Classic.

There are two options. First, a first-author query, entered as ^huchra, j. in Classic, works similarly in the new ADS—the author: tag is not necessary for first-author searches. Second, many search tags will autocomplete in the search box. Begin typing the search tag, such as author:, and either press the return key or the right arrow key when the tag autocompletes to accept it.

Q: Is it possible to search using the second author of a paper?

Positional searches are supported. To search for a second author, use pos(author:“huchra,j.”,2). See the Help page for positional field searches for more info.

Either prepend a negative sign (e.g. -doctype:“proposal”) or use the Boolean operator NOT (e.g. NOT doctype:“proposal”) while searching. See the Help page for Boolean queries for more info, paying special attention to the note on when differences in behavior between NOT and the negative sign may arise.

Q: Records are missed when searching from the 1st of one month to the end of the current month, e.g. pubdate:[2016-01-01 TO 2016-06-30].

Records do not generally have a publication day, just a month and year. The missing day is set to 00 (e.g. January 2016 is set to 2016-01-00). Searches starting on the 1st of a given month will exclude all records with publication days of 00. It is preferable to not use a day when searching over a publication date range; specifying only a month will include records with publication days of 00. This is similarly true for the small number of records missing publication months. Searches beginning in January of a given year may miss records with publication months of 00. To search for records from the first half of the year, employ a search term such as pubdate:[2016 TO 2016-06].

Q: How can I search for an acronym that is the same as a common word?

ADS treats search terms entered in all caps as acronyms and will only return records that contain the all caps acronym form, not the lowercase common word form. In addition, some acronyms will auto-expand in the search (e.g. searching for “ADS” will find both “ADS” and “Astrophysics Data System” but will ignore “ads”).

Q: My new paper is not appearing in ADS.

New papers appearing on arXiv are ingested daily, though there may be a delay of one day for them to appear in the new ADS. Published articles are ingested as the publisher provides them on a weekly basis, generally over the weekend.

Q: Searching for an author’s name plus their affiliation doesn’t give a complete list of results.

The affiliation search is still in beta. Not all publishers provide authors’ affiliations for search indexing, even if the affiliations are listed in the PDF or HTML form of the article itself. Also, affiliations do not yet have canonical forms: searching for “Harvard-Smithsonian Center for Astrophysics” or for “CfA” will give different results. We are working on a new affiliations search module that will provide canonical forms of affiliations to ease searching—we hope to enable this sometime in 2018.

Classic Search Translator

Q: Why is there a new search option in ADS?

As we prepare to wind down the search engine and interface which ADS has provided to its users for the past 25 years in favor of a more modern search system, we want to provide our users an easy way to transition from the old system to the new. The so-called ADS Classic query form now has an additional button which will take the query parameters entered by the user, translate them in the syntax used by our new search engine, and provide results in the new interface.

Q: Why do Classic and the new ADS return very different numbers of results?

By default, if search terms are entered into more than one box of the Classic query form, the results are combined with a Boolean OR. This returns results that match one or more of the search terms, with results that match all of the search terms listed at the top of the search results list. When the search terms are sent to the new ADS, the search terms are combined using a Boolean AND, so all results match all of the search terms. This removes results that are less relevant to the search, decreasing the total number of results returned. If you prefer some search terms to be optional, edit the query in the search box in the new ADS to use the Boolean OR operator instead.

Q: My search returned too many results. Do I have to go back to Classic to add more search terms?

Nope! The easiest way to narrow the search results is to use the filters in the left and right columns, on either side of the search results list. You can also edit the query directly in the search box at the top of the screen.

Some lesser-used parameters, such as non-default values of the result relative weights, are not transmitted to your search in the new ADS. For the most part, these warnings can be ignored as they don’t significantly modify the search selection.

Q: Why are my results sorted in a different order in the new ADS than in Classic?

By default, results are generally sorted in reverse chronological order in the new ADS, while in Classic, they’re first sorted by relevance and then by date. Development of a new relevance sort is currently underway for the new ADS. In the meantime, try sorting by score, which sorts based on how well a record matches the given search terms. Or to see more popular results, sort by citation count or by read count.

Q: I’ve heard I can search full text (or author affiliations, acknowledgments, etc.) in the new ADS. How do I enter that query in Classic?

The Classic search translator doesn’t offer the new functionality. To use these new search features, start your search within the new ADS Modern Form. To search the full text, use the full: operator prepended to your search terms. See our Search Syntax help page for more information.

Q: I like the new interface but can I keep entering search terms in a form rather than a single box?

Yes! The new interface offers a search form with a similar layout to the Classic multi-box search. However, keep in mind that the new ADS Classic Form does not offer access to the more advanced search features, such as the full text search.

Transitioning from Classic

Q: Sometimes Classic will display more results for a given search than the new ADS will. The total number of results returned by Classic seems to depend on the number of results shown per page.

Both Classic and the new ADS will show a single record only once in the search results and will combine a record’s published and arXiv versions into a single listing in the results in order to do so. In the new ADS, this merging of arXiv and published versions of a record occurs before the total number of records is calculated. In Classic, this merging happens when a record’s listing is displayed in the search results and has not yet been performed for records on a page further down the search results. Thus the real total number of records returned by a Classic search isn’t known until all results have been displayed, by paging through the results. Thus Classic may initially show a higher total number of results than has actually been found.

Q: The number of reads for a given record is different between Classic and the new ADS.

The number of reads for a record in Classic (seen under the Reads History link from an abstract page) and in the new ADS (seen by clicking on Metrics from an abstract page) is the same; this figure is the number of times an abstract page has been accessed or the full text downloaded on ADS by distinct users. A second type of usage data, the recent reads, is available in the new ADS on the right side of the search results. This adds the number of reads on arXiv in the last 90 days to the number of reads in ADS over the same time period and thus may be higher than the number of reads seen on an abstract page for newer records.

Q: How do I transfer a private library from Classic to the new ADS?

The easiest method is to link your Classic account to your the new ADS account and use our import tool to transfer your library. If this is not an option, you may also perform the following: 1. In Classic, select all records in the library you wish to transfer. 2. At the bottom of the page, select the button “Export selected records to the new ADS.” 3. In the new ADS, perform any additional filtering that may be necessary. 4. Select all records (using the select all box at the top, if necessary) and use the buttons in the right panel to add the records to a library.

Nope! Existing Classic URLs will continue to work, even after Classic is retired.

Q: Where do I find the utility Get citation lists for selected articles and similar second order queries?

In general, the function Reviews in the Explore menu will generate the same list of publications as selecting all records in the old ADS and clicking on the button Get citation lists for selected articles. The only difference is the fact that the new ADS does not show the frequency, but the results are sorted by the number of cites to the original set (when sorted by score).

The new function Useful can be used in a similar way to generate the same results you would get the with button Get reference lists for selected articles in the old ADS. When “score” is selected for sorting, the records are sorted by the number of cites by the original set.

The Co-reads function corresponds with Get also-read lists for selected articles.

ADS Libraries

Q: If I delete a record from the middle of a large private library, the page refreshes and deposits me back on the first page.

To return to your previous position, use the jump-to box at the bottom of the list of records, between the previous and next page buttons.

Q: The number of papers listed in the header of my library differs from the actual number in the library.

When you create or update your library, the bibcodes of the new records are stored in a database. Currently this list does not get updated when records are merged or deleted within the ADS index, rather these changes get reflected at display time of the contents of an ADS Library.


ORCID claims can take up to 24 hours to be processed and approved in our system. Please check the search again tomorrow.

Database Coverage

Q: How complete is ADS?

ADS aims to be the complete and authoritative source for the astrophysics literature. This includes not only published refereed articles and arXiv e-prints, but also the gray literature, comprised of conference proceedings, books, proposals, etc. We aim to not only index these resources but also enrich them with links to data or other resources when available. We also index published refereed papers and conferences that are likely to be cited by the core astrophysics literature, such as papers from physics, geophysics, and planetary science. If a record is missing, please let us know via our Submit Abstract Form.

Q: Why are citations from an arXiv record missing? Why is an arXiv record missing its references?

For arXiv sources, we attempt to extract references from the full text and from there create citations. However, as papers can be submitted to the arXiv with a bibliography in a non-standard format, this process is not always successful. When the published version of an arXiv paper becomes available, we will use the publisher-provided reference list and disregard the arXiv reference list.

Q: For how many records is the full text available for searching?

The full text is available for searching for over 4 million records, including most recent publications. Note that the searchable full text resides in our database and is separate from the links to publisher or arXiv sources; not all records with source links have searchable full text.


Q: I’m trying to use the new interface but I’m getting a message about JavaScript / it’s stuck on a loading screen.

This issue is commonly seen when users have JavaScript turned off in their browser, or they’re using security software or browser plugins (such as NoScript) that block JavaScript, or are accessing the site from a network that blocks content from certain domains (e.g. The new ADS requires JavaScript in order to function. At an absolute minimum you must have JavaScript turned on. Further, if you have any security settings or plugins that require sites to be whitelisted before running JavaScript, you must whitelist two domains for basic functionality:, and

Q: What internet browsers are supported by ADS?

We support all current versions (within the last 5 years) of Chrome, Firefox, Safari, and Edge. We also support Internet Explorer 11. This includes Firefox ESR (extended service release) versions, but does not include versions of any browser newer than 5 years old that have been officially retired.

Q: How should I acknowledge ADS?

If you wish to acknowledge us in a publication, kindly use a phrase such as the following: “This research has made use of NASA’s Astrophysics Data System Bibliographic Services.” If you are using the ADS as a tool for bibliometric studies, please make sure you have an in-depth understanding of the system, its features and limitations, by reading and citing as appropriate the relevant published literature about ADS (refereed, non-refereed).