Chandra Bibliographic Statistics

Tracking Scientific Productivity:

To evaluate the relative scientific effectiveness of Chandra observations, we have undertaken to compile and study data on related publications. Across institutions and even across disciplines, professional publications and citations represent the most commonly used and accepted method of tracking scientific productivity. See the March 2004 Newsletter article describing this effort.

Basic Annual Bibliographic Statistics (as of 2025-04-06) :

The basic annual bibliographic statistical data for the Chandra X-ray Observatory pertain to papers on Chandra observations. These papers fall into two groups: those that present specific Chandra observations (Category 1) and those that refer to published Chandra results with complementary observations, follow-up analysis, or theoretical analysis (Category 2 with flags A, B, or C). We define these as Chandra Science Papers.

Year	Refereed Chandra Science Papers	Number of Citations to these Papers	All Chandra Science Papers	Observations Published in Refereed Papers *
2000	55	8142	60	104
2001	198	20274	217	439
2002	330	27932	380	1074
2003	431	31744	521	1830
2004	400	26304	497	2233
2005	447	28262	578	3089
2006	549	40236	688	2317
2007	499	32439	610	2325
2008	519	28970	674	4503
2009	432	26707	552	5444
2010	421	25380	534	4050
2011	441	23602	577	5871
2012	453	25569	552	7534
2013	425	23200	518	7470
2014	405	20364	492	6705
2015	429	20668	491	7411
2016	440	19223	530	7473
2017	472	25493	579	11065
2018	459	15509	515	7935
2019	421	11013	471	9748
2020	390	8358	416	13202
2021	378	6775	410	4647
2022	367	5088	378	6299
2023	440	3605	453	6303
2024	498	2228	515	17619
2025	106	261	107	1309
Total	10405	507346	12315

* Note: this is a lower limit since it refers to Category 1 papers only.

The Chandra Bibliography Database:

The Chandra Bibliography Database allows the public to search all Chandra-related articles and to follow links from the data to the literature, as well as from the literature to the data. Thanks to the Astrophysics Data System (ADS), publication data are highly complete, and relatively easy to track. We query the ADS daily for publications related to Chandra or to X-ray astronomy, and we are complete from before Chandra's launch. We review the publications, categorize them by several different parameters, and enter them into the Bibliography Database. For publications that present, analyze, or refer to Chandra data, we determine the ObsIds involved (either from the text or by asking the authors). ObsIds allow links to other information, such as Chandra Proposal Database items like scientific category and proposal type.

(You Know What They Say About) Statistics:

The Chandra Biliography Database allows for the compilation of a large number of publication statistics. We create selected data tables and plots, linked below, which are updated monthly. The resulting plots and statistics have the potential for misinterpretation, unless one is alert to embedded assumptions and details affecting the tally. For instance, most plots linked here (except those by publication year) include only refereed journal articles that present specific Chandra observations, and all plots tally only programs whose observations are complete. We strongly recommend reading both the NOTES and CAVEATS and the DEFINITIONS and CONVENTIONS, as a guide for interpreting the plots linked below. If you have pressing questions or concerns, please contact Paul Green of the Chandra Director's Office.

Plots and Data:

Refereed Chandra Science Papers by Publication Year
Citations to Refereed Chandra Science Papers by Publication Year
Plots and Data for Category 1 papers only

Supporting Documents:

NOTES and CAVEATS
DEFINITIONS and CONVENTIONS