XMMU J134736.6+173403: an eclipsing LMXB in quiescence or a peculiar AGN?

Abstract

Aims. We report the discovery of a peculiar object observed serendipitously with XMM-Newton. We present its timing and spectral properties and investigate its optical counterpart. Methods. The light curve of the X-ray source, its spectrum, and the spectrum of the best optical counterpart are presented and analyzed. Results. The X-ray flux decreases by a factor of 6.5 within 1 h and stays in a low state for at least 10 h, thereby suggesting the presence of an eclipse. The spectrum is very soft, a power law with a slope of Gamma~2.8, and does not change significantly before and after the flux drop. The source is spatially coincident within few arc-seconds with a Seyfert~2 galaxy belonging to a galaxy pair. Conclusions. Although the background AGN seems the best counterpart, neither the temporal nor the spectral properties of the X-ray source are compatible with it. We investigate the possibility of having a foreground low-mass X-ray binary in quiescence, where the companion is not detected in the optical wavelength.

arXiv commentAccepted in A&A as a Research Note. 4 pages, 4 figures

References in corpus (13)

• The European Photon Imaging Camera on XMM-Newton: The MOS Cameras
• On characterising the variability properties of X-ray light curves from active galaxies
• The distribution of absorbing column densities among Seyfert 2 galaxies
• A New Model for Black Hole Soft X-ray Transients in Quiescence
• Variable Thermal Emission from Aql X-1 in Quiescence
• On the Lack of Thermal Emission from the Quiescent Black Hole XTE J1118+480: Evidence for the Event Horizon
• Correlated X-ray and Optical Variability in V404 Cyg in Quiescence
• The variable quiescence of Cen X-4
• A Variable Ultraluminous Supersoft X-ray Source in "The Antennae": Stellar-Mass Black Hole or White Dwarf?
• A Composite Seyfert 2 X-ray Spectrum: Implications for the Origin of the Cosmic X-ray Background
• The evolution of the high energy tail in the quiescent spectrum of the soft X-ray transient Aql X-1
• An SDSS Survey For Resolved Milky Way Satellite Galaxies I: Detection Limits
• The Spectrum of the Black Hole X-ray Nova V404 Cygni in Quiescence as Measured by XMM-Newton

Cited by in corpus (2)

• Exploring X-ray variability with unsupervised machine learning I. Self-organizing maps applied to XMM-Newton data
• Discovery of a 23.8h QPO in the SWIFT light curve of XMMU J134736.6+173403