The recurrent ultra-luminous X-ray transient NGC 253 ULX1

Abstract

We present the results of ROSAT and XMM-Newton observations of the recurrent ultraluminous X-ray source (ULX) NGC 253 ULX1. This transient is one of the few ULXs that was detected during several outbursts. The luminosity reached 1.4 10^39 erg s^-1 and 0.5 10^39 erg s^-1 in the detections by ROSAT and XMM-Newton, respectively, indicating a black hole X-ray binary with a mass of the compact object of >11 M_sun. It is highly unlikely that this source is a foreground source or a background AGN. In the ROSAT detection NGC 253 ULX1 showed significant variability, whereas the luminosity was constant in the detection from XMM-Newton. The XMM-Newton EPIC spectra are well-fit by a bremsstrahlung model (kT=2.24 keV, N_H=1.74 10^20 cm^-2), which can be used to describe a comptonized plasma. No counterpart was detected in the optical I, R, B, NUV and FUV bands to limits of 22.9, 24.2, 24.3, 22 and 23 mag, respectively, pointing at a X-ray binary with a low mass companion.

arXiv comment5 pages, 4 figures; accepted for publication in A&A

References in corpus (10)

• The USNO-B Catalog
• Ultraluminous X-Ray Sources in External Galaxies
• The second US Naval Observatory CCD Astrograph Catalog (UCAC2)
• The Nature of Ultra-Luminous Compact X-Ray Sources in Nearby Spiral Galaxies
• Super-Eddington Fluxes from Thin Accretion Disks?
• A Comparison of Intermediate Mass Black Hole Candidate ULXs and Stellar-Mass Black Holes
• Ultra-luminous X-ray Sources in nearby galaxies from ROSAT HRI observations I. data analysis
• ASCA observations of the nearby galaxies Dwingeloo 1 and Maffei 1
• XMM-Newton observation of SN1993J in M81
• XMM-Newton Spectroscopy of Bright ULX Sources in the Antennae Galaxies (NGC 4038/4039)

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• The fading of two transient ULXs to below the stellar mass Eddington limit
• Measuring the black hole mass in Ultraluminous X-ray Sources with the X-ray Scaling Method
• The X-ray Nature of Nucleus in Seyfert 2 Galaxy NGC 7590