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XMM-Newton Slew Survey Extragalactic Sample

Metadata Updated: September 19, 2025

The ongoing XMM-Newton Slew Survey (XSS) provides coverage of a significant fraction of the sky in a broad X-ray bandpass. Although shallow by contemporary standards, in the "classical" 2-10 keV band of X-ray astronomy the XSS provides significantly better sensitivity than any currently available all-sky survey. The authors investigate the source content of the XSS, focusing on detections in the hard 2-10 keV band down to a very low threshold (>= 4 counts net of background). At the faint end, the survey reaches a flux sensitivity of roughly 3 x 10<sup>-12</sup> erg/cm<sup>2</sup>/s (2-10 keV). The starting point was a sample of 487 sources detected in the XSS (up to and including release XMMSL1d2) at high galactic latitude in the hard band. Through cross-correlation with published source catalogs from surveys spanning the electromagnetic spectrum from radio through to gamma-rays, they find that 45% of the sources have likely identifications with normal/active galaxies. A further 18% are associated with other classes of X-ray object (nearby coronally active stars, accreting binaries, clusters of galaxies), leaving 37% of the XSS sources with no current identification. The authors go on to define an XSS extragalactic sample comprised of 219 galaxies and active galaxies selected in the XSS hard band. They investigate the properties of this extragalactic sample including its X-ray log N - log S distribution, and it is this sample that is contained in this table. The authors find that, in the low-count limit, the XSS is, as expected, strongly affected by Eddington bias. There is also a very strong bias in the XSS against the detection of extended sources, most notably clusters of galaxies. A significant fraction of the detections at and around the low-count limit may be spurious. Nevertheless, it is possible to use the XSS to extract a reasonably robust sample of extragalactic sources, excluding galaxy clusters. The differential log N - log S relation of these extragalactic sources matches very well to the HEAO-1 A2 all-sky survey measurements at bright fluxes and to the 2XMM source counts at the faint end. The substantial sky coverage afforded by the XSS makes this survey a valuable resource for studying X-ray bright source samples, including those selected specifically in the hard 2 - 10 keV band. This table was created by the HEASARC in December 2012, based on the <a href="https://cdsarc.cds.unistra.fr/ftp/cats/J/A+A/548/A99">CDS Catalog J/A+A/548/A99</a> file tablea1.dat. This is a service provided by NASA HEASARC .

Access & Use Information

Public: This dataset is intended for public access and use. License: No license information was provided. If this work was prepared by an officer or employee of the United States government as part of that person's official duties it is considered a U.S. Government Work.

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Dates

Metadata Created Date April 11, 2025
Metadata Updated Date September 19, 2025

Metadata Source

Harvested from NASA Data.json

Additional Metadata

Resource Type Dataset
Metadata Created Date April 11, 2025
Metadata Updated Date September 19, 2025
Publisher High Energy Astrophysics Science Archive Research Center
Maintainer
Identifier ivo://nasa.heasarc/xmmslewegs
Data Last Modified 2025-09-10
Category Astrophysics
Public Access Level public
Bureau Code 026:00
Metadata Context https://project-open-data.cio.gov/v1.1/schema/catalog.jsonld
Schema Version https://project-open-data.cio.gov/v1.1/schema
Catalog Describedby https://project-open-data.cio.gov/v1.1/schema/catalog.json
Harvest Object Id d9273e2a-b0a4-4c17-97ed-ebea2222d1c7
Harvest Source Id 58f92550-7a01-4f00-b1b2-8dc953bd598f
Harvest Source Title NASA Data.json
Homepage URL https://heasarc.gsfc.nasa.gov/W3Browse/all/xmmslewegs.html
Program Code 026:000
Source Datajson Identifier True
Source Hash 21dbab3bddf0c7c3ad832f158b3b059a665d6088c2f718379595bf4eba28042b
Source Schema Version 1.1

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