Chandra Observations of the Nucleus of M33

Abstract

The nearby galaxy M33 hosts the most luminous steady X-ray source in the Local Group. The high spatial resolution of Chandra allows us to confirm that this ultra-luminous X-ray source is within the nucleus and rule out at the 4.6 sigma level a previously proposed possible counterpart located 1" away. The X-ray spectrum is well fitted by a disc blackbody with kT=1.18+-0.02 keV and R cos(theta)^(0.5}=57+-3 km, consistent with earlier results from ASCA and BeppoSAX. The source flux is steady between 1 and 1e4 s (<3% rms variability, 0.5-10 keV) with a 0.5-10 keV luminosity of 1.5e39 erg/s. The X-ray properties and an association with a radio source are reminiscent of the galactic microquasar GRS 1915+105.

5 pages, 4 figures, accepted for publication in MNRAS

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• XMM-Newton Observations of the Ultraluminous Nuclear X-ray Source in M33
• Spectral variability of the nucleus of M33 in a Chandra-ACIS observation
• NIR Counterparts to ULXs (III): Completing the photometric survey and selected spectroscopic results
• Revealing the Supernova Remnant Population of M33 with Chandra
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• Deep XMM-Newton survey of M33
• Central X-ray point-sources found to be abundant in low-mass, late-type galaxies predicted to contain an intermediate-mass black hole
• NuSTAR observations of the ultraluminous X-ray source M33 X-8: a black hole in a very high state?
• A Transient Sub-Eddington Black Hole X-ray Binary Candidate in the Dust Lanes of Centaurus A
• Soft X-ray emission from the inner disk of M33
• Formation and Evolution of Supermassive Black Holes