A deep XMM-Newton survey of M33: Point-source catalog, source detection, and characterization of overlapping fields

Journal Article · Fri May 01 04:00:00 EDT 2015 · Astrophysical Journal, Supplement Series

DOI:https://doi.org/10.1088/0067-0049/218/1/9· OSTI ID:22872450

Williams, Benjamin F.; Wold, Brian; Garofali, Kristen ^[1]; Haberl, Frank; Pietsch, Wolfgang ^[2]; Blair, William P.; Kuntz, K. D. ^[3]; Gaetz, Terrance J.; Plucinsky, Paul P. ^[4]; Long, Knox S. ^[5]; Pannuti, Thomas G. ^[6]

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1. University of Washington Astronomy Department, Box 351580, Seattle, WA 98195 (United States)
2. Max-Planck-Institut für extraterrestrische Physik, Giessenbachstraße, D-85748 Garching (Germany)
3. Department of Physics and Astronomy, Johns Hopkins University, 3400 North Charles Street, Baltimore, MD 21218 (United States)
4. Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States)
5. Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218 (United States)
6. Space Science Center, Department of Earth and Space Sciences, 235 Martindale Drive, Morehead State University, Morehead, KY 40351 (United States)

We have obtained a deep 8 field XMM-Newton mosaic of M33 covering the galaxy out to the D{sub 25} isophote and beyond to a limiting 0.2–4.5 keV unabsorbed flux of 5 × 10{sup −16} erg cm{sup −2} s{sup −1} (L > 4 × 10{sup 34} erg s{sup −1} at the distance of M33). These data allow complete coverage of the galaxy with high sensitivity to soft sources such as diffuse hot gas and supernova remnants (SNRs). Here, we describe the methods we used to identify and characterize 1296 point sources in the 8 fields. We compare our resulting source catalog to the literature, note variable sources, construct hardness ratios, classify soft sources, analyze the source density profile, and measure the X-ray luminosity function (XLF). As a result of the large effective area of XMM-Newton below 1 keV, the survey contains many new soft X-ray sources. The radial source density profile and XLF for the sources suggest that only ∼15% of the 391 bright sources with L > 3.6 × 10{sup 35} erg s{sup −1} are likely to be associated with M33, and more than a third of these are known SNRs. The log(N)–log(S) distribution, when corrected for background contamination, is a relatively flat power law with a differential index of 1.5, which suggests that many of the other M33 sources may be high-mass X-ray binaries. Finally, we note the discovery of an interesting new transient X-ray source, which we are unable to classify.

• OSTI ID: 22872450
• Journal Information: Astrophysical Journal, Supplement Series, Journal Name: Astrophysical Journal, Supplement Series Journal Issue: 1 Vol. 218; ISSN 0067-0049; ISSN APJSA2
• Country of Publication: United States
• Language: English

Related Subjects

79 ASTRONOMY AND ASTROPHYSICS
BINARY STARS
CATALOGS
DETECTION
GALAXIES
KEV RANGE
LUMINOSITY
MASS
POINT SOURCES
SOFT X RADIATION
SUPERNOVA REMNANTS
X-RAY SOURCES