2004/01/15 by V. Mangano, Vanessa Mangano, G. L. Israel +3
Physics and Astronomy · #Absorption (acoustics) #Astronomy and Astrophysical Research #Astrophysical Phenomena and Observations #Field (mathematics) #Flux (metallurgy) #Galaxies: Formation, Evolution, Phenomena #Magnetic field #Photon #Power law #Source counts #Spectral line #astro-ph
paper · pdf · doi:10.1051/0004-6361:20040099
published as Astron.Astrophys. 419 (2004) 1045-1056 · Accepted for publication in A&A, 16 pages, 8 postscript figures
arxiv created 2004/01/15 · openalex publication_date 2004/05/07 · arxiv updated 2009/12/01 · openalex created_date 2016/06/24 · openalex updated_date 2026/08/05
We report the discovery of the new dipping X-ray source, XMMU J004308.6+411247, in M 31, during a systematic search for periodicities in XMM-Newton archival observations. During the 2002 January 6 observation, the dips recur with a 107 min period and the source count rate is consistent with zero at the dip minimum. Dips with the same modulation and period are also observed during the XMM-Newton observations carried out on 2000 June 25, 2001 June 29 and the Chandra observation of 2001 October 5. The dips of XMMU J004308.6+411247 show no evidence of energy dependence. The average X-ray flux of XMMU J004308.6+411247 is nearly constant across different observations ( erg s-1 for an assumed M 31 distance of 780 kpc in the 0.3-10 keV band); the spectrum is well fitted by an absorbed power law with a photon index ∼0.8 or an absorbed Comptonization model. The photo-electric absorption is consistent with the Galactic value in the source direction. If XMMU J004308.6+411247 is located in M 31 its properties are consistent with those of dipping low mass X-ray binaries in the Galaxy. Present observations do not make it possible to distinguish between dips and eclipses. The possibility that XMMU J004308.6+411247 is a foreground X-ray source cannot be ruled out at present; in this case the source might be a magnetic cataclysmic variable.