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Small Magellanic Cloud XMM-Newton Point Source Catalog

Metadata Updated: October 30, 2025

The XMM-Newton survey of the Small Magellanic Cloud (SMC) yielded complete coverage of the bar and eastern wing in the 0.2-12.0 keV energy band. In addition to the main-field (5.58 deg<sup>2</sup>), available outer fields were included in the catalogue, yielding a total field area of 6.32 deg<sup>2</sup>. This catalog comprises 3,053 unique X-ray point sources and sources with moderate extent that have been reduced from 5,236 individual detections found in 100 observations between April 2000 and April 2010 (the details of these exposures are given in Table B.1 of the reference paper). For 927 sources, there were detections at multiple epochs, with some SMC fields observed up to 36 times. The detected sources have a median position uncertainty of 1.3 arcseconds (1 sigma) and limiting fluxes down to ~1 x 10<sup>-14</sup> erg/s/cm<sup>2</sup> in the 0.2-4.5 keV band, corresponding to X-ray luminosities of ~5 x 10<sup>33</sup> erg/s for sources located in the SMC. Sources have been classified using X-ray hardness ratios, X-ray variability, and their multi-wavelength properties. In their paper, the authors discuss the statistical properties of the detected X-ray sources, like the spatial distribution, X-ray color diagrams, luminosity functions, and time variability. They have identified 49 SMC high-mass X-ray binaries (HMXB), four super-soft X-ray sources (SSS), 34 foreground stars, and 72 active galactic nuclei (AGN) behind the SMC. In addition, they found candidates for SMC HMXBs (45) and faint SSSs (8) as well as AGN (2092) and galaxy clusters (13). Notice that X-ray sources with high extent (>40 arcseconds), e.g. supernova remnants and galaxy clusters, have been previously presented by Haberl et al. (2012, A&A, 545, A128) and are not included in this table. To investigate the spectral behavior of all sources, the authors used hardness ratios HR<sub>i</sub> (i = 1, 2, 3, 4), defined by HR<sub>i</sub> = (R<sub>i+1</sub> - R<sub>i</sub>)/(R<sub>i+1</sub> + R<sub>i</sub>), where R<sub>i</sub> is the count rate in energy band i as defined by: <pre> Band Energy Range 1 0.2-0.5 keV 2 0.5-1.0 keV 3 1.0-2.0 keV 4 2.0-4.5 keV 5 4.5-12. keV </pre> To increase statistics, the authors also calculated average HR_i<sub>s</sub>, combining all available instruments and observations. HR<sub>i</sub> is not given if both rates R<sub>i</sub> and R<sub>i+1</sub> are null or if the 1-sigma uncertainty of Delta(HR<sub>i</sub>) covers the complete HR interval from -1 to +1. To convert an individual count rate R<sub>i</sub> of an energy band i into a setup-independent, observed flux F<sub>i</sub>, the authors calculated energy conversion factors (ECFs) f<sub>i</sub> = R<sub>i</sub>/F<sub>i</sub> , as described in Sect. A.3 of the reference paper. For the calculation, they assumed a universal spectrum for all sources, described by a power-law model with a photon index of 1.7 and a photo-electric foreground absorption by the Galaxy of N<sub>H,Gal</sub> = 6 x 10<sup>20</sup> cm<sup>-2</sup> (average for the SMC main field in the H I map of Dickey & Lockman 1990, ARAA, 28, 215). In addition to the fluxes for each detection, the authors calculated flux upper limits F<sub>UL</sub> for each observation and source, if the source was observed but not detected in an individual observation. As for the initial source detection, they used the emldetect task to fit sources, but kept the source positions fixed at the master positions and accepted all detection likelihoods in order to get an upper limit for the flux. This table was created by the HEASARC in October 2013 based on <a href="https://cdsarc.cds.unistra.fr/ftp/cats/J/A+A/558/A3">CDS Catalog J/A+A/558/A3</a> file smc_src.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 October 30, 2025

Metadata Source

Harvested from NASA Data.json

Additional Metadata

Resource Type Dataset
Metadata Created Date April 11, 2025
Metadata Updated Date October 30, 2025
Publisher High Energy Astrophysics Science Archive Research Center
Maintainer
Identifier ivo://nasa.heasarc/smcpscxmm
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 470546d1-1c64-41b3-a723-d647792166fe
Harvest Source Id 58f92550-7a01-4f00-b1b2-8dc953bd598f
Harvest Source Title NASA Data.json
Homepage URL https://heasarc.gsfc.nasa.gov/W3Browse/all/smcpscxmm.html
Program Code 026:000
Source Datajson Identifier True
Source Hash d70956d5995237da815bbc3af2599e6bcfa76779e2b088fb07b8c937d40bcd71
Source Schema Version 1.1

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