Skip to main content
U.S. flag

An official website of the United States government

This site is currently in beta, and your feedback is helping shape its ongoing development.

ROSAT/XMM-Newton 13-hour Field Chandra X-Ray Source Catalog

Published by High Energy Astrophysics Science Archive Research Center | National Aeronautics and Space Administration | Metadata Last Checked: February 21, 2026 | Last Modified: 2026-02-17
This table contains some of the results from a Chandra ACIS-I survey of a high-latitude region at RA, Dec = 13 hours, +38 degrees which was earlier observed with ROSAT and which had recently been observed by XMM-Newton for 200 ks. XMM-Newton was expected to provide good-quality X-ray spectra for over 200 sources with fluxes around the knee of the log N /log S distribution, which are responsible for the bulk of the X-ray background. The main aim of the Chandra observations was to provide arcsecond, or better, positions, and hence reliable identifications, for the XMM-Newton sources. The ACIS-I observations were arranged in a mosaic of four 30-ks pointings, covering almost all of the 15-arcminute radius XMM-Newton/ROSAT field. 214 Chandra sources were detected above a Cash likelihood statistic of 25, which approximates to a 5-sigma significance, to a limiting flux of ~ 1.3 x 10<sup>-15</sup>erg/cm<sup>2</sup>/s (0.5 - 7 keV). Optical counterparts were derived from a Subaru SuprimeCam image reaching to R ~ 27. The very large majority of the Chandra sources have an optical counterpart, with the distribution peaking at 23 < R < 24, although 14 have no counterpart to R = 27. The fraction of X-ray sources with no identification brighter than R = 27 is similar to that found in deeper Chandra surveys. The majority of the identifications are with galaxies. As found in other Chandra surveys, there is a very wide range of optical magnitudes for a given X-ray flux, implying a range of emission mechanisms, and many sources have high L<sub>X</sub>/L<sub>opt</sub> ratios, implying absorption at moderate redshift. Comparison with the earlier ROSAT survey shows that the accuracy of the ROSAT positions agrees very well with the predictions from simulations by McHardy et al. and that the large majority of the identifications were correct. This table was created by the HEASARC in July 2013 based on <a href="https://cdsarc.cds.unistra.fr/ftp/cats/J/MNRAS/342/802">CDS Catalog J/MNRAS/342/802</a> files table2.dat and table5.dat. This is a service provided by NASA HEASARC .

Find Related Datasets

Click any tag below to search for similar datasets

data.gov

An official website of the GSA's Technology Transformation Services

Looking for U.S. government information and services?
Visit USA.gov