Discovery and Interpretation of an X-Ray Period in the Galactic Center Source CXOGC J174536.1–285638

We present X-ray and infrared observations of the X-ray source CXOGC J174536.1–285638. Previous observations suggest that this source may be an accreting binary with a high-mass donor (HMXB) or a colliding wind binary (CWB). Based on the Chandra and XMM-Newton light curve, we have found an apparent 189 ± 6 day periodicity with better than 99.997% confidence. We discuss several possible causes of this periodicity, including both orbital and superorbital interpretations. We explore in detail the possibility that the X-ray modulation is related to an orbital period and discuss the implications for two scenarios; one in which the variability is caused by obscuration of the X-ray source by a stellar wind, and the other in which it is caused by an eclipse of the X-ray source. We find that in the first case, CXOGC J174536.1–285638 is consistent with both CWB and HMXB interpretations, but in the second, CXOGC J174536.1–285638 is more likely a HMXB.

[1]  H. Murakami,et al.  Suzaku X-Ray Spectroscopy of a Peculiar Hot Star in the Galactic Center Region , 2007, 0712.0280.

[2]  S. Smartt,et al.  The VLT-FLAMES survey of massive stars: wind properties and evolution of hot massive stars in the Large Magellanic Cloud , 2007, 0704.1113.

[3]  Nicolas Produit,et al.  A description of sources detected by INTEGRAL during the first 4 years of observations , 2007, astro-ph/0703043.

[4]  L. Titarchuk,et al.  Power Spectra of Black Holes and Neutron Stars as a Probe of Hydrodynamic Structure of the Source: Diffusion Theory and Its Application to Cygnus X-1 and Cygnus X-2 X-Ray Observations , 2006, astro-ph/0612675.

[5]  P. Crowther,et al.  Physical Properties of Wolf-Rayet Stars , 2006, astro-ph/0610356.

[6]  M. Schurch,et al.  A search for counterparts to massive X-ray binaries using photometric catalogues ,⋆ , 2006, astro-ph/0610006.

[7]  M. Irwin,et al.  The UKIRT Infrared Deep Sky Survey (UKIDSS) , 2006, astro-ph/0604426.

[8]  A. Pollock,et al.  XMM-Newton observations of the massive colliding wind binary and non-thermal radio emitter Cyg OB2#8A [O6If+O5.5III(f)] , 2006 .

[9]  S. Eikenberry,et al.  Identification of the Infrared Counterpart to a Newly Discovered X-Ray Source in the Galactic Center , 2006, astro-ph/0607147.

[10]  T. Oosterbroek,et al.  Unveiling the nature of the highly absorbed X-ray source SAX J1748.2-2808 with XMM-Newton , 2006, astro-ph/0606307.

[11]  W. Lewin,et al.  Compact stellar X-ray sources , 2006 .

[12]  J. Tomsick,et al.  Identifications of Four INTEGRAL Sources in the Galactic Plane via Chandra Localizations , 2006, astro-ph/0603810.

[13]  S. Farrell,et al.  Super-orbital periods in X-ray binaries , 2006 .

[14]  N. Gehrels,et al.  Swift, INTEGRAL, RXTE, and Spitzer Reveal IGR J16283–4838 , 2005, astro-ph/0506170.

[15]  S. Chaty,et al.  The Optical/Near-Infrared Counterpart of the INTEGRAL Obscured Source IGR J16318–4848: An sgB[e] in a High-Mass X-Ray Binary? , 2004, astro-ph/0408407.

[16]  John T. Rayner,et al.  Spextool: A Spectral Extraction Package for SpeX, a 0.8–5.5 Micron Cross‐Dispersed Spectrograph , 2004 .

[17]  E. Feigelson,et al.  The Spectra and Variability of X-Ray Sources in a Deep Chandra Observation of the Galactic Center , 2004, astro-ph/0403463.

[18]  H. Sana,et al.  A phase-resolved XMM–Newton campaign on the colliding-wind binary HD 152248 , 2004, astro-ph/0402412.

[19]  MIT,et al.  Diffuse X-Ray Emission in a Deep Chandra Image of the Galactic Center , 2004, astro-ph/0402087.

[20]  John T. Rayner,et al.  SpeX: A Medium‐Resolution 0.8–5.5 Micron Spectrograph and Imager for the NASA Infrared Telescope Facility , 2003 .

[21]  J. Clark,et al.  Near IR spectroscopy of the X-ray binary Circinus X-1 , 2003 .

[22]  W. N. Brandt,et al.  A Deep Chandra Catalog of X-Ray Point Sources toward the Galactic Center , 2003, astro-ph/0301371.

[23]  H Germany,et al.  A Method of Correcting Near‐Infrared Spectra for Telluric Absorption , 2002, astro-ph/0211255.

[24]  M. Coe,et al.  Long-term properties of accretion discs in X-ray binaries – I. The variable third period in SMC X-1 , 2002, astro-ph/0210241.

[25]  L. Girardi,et al.  Theoretical isochrones in several photometric systems I. Johnson-Cousins-Glass, HST/WFPC2, HST/NICMOS, Washington, and ESO Imaging Survey filter sets , 2002, astro-ph/0205080.

[26]  J. Lee,et al.  The First High-Resolution X-Ray Spectrum of Cygnus X-1: Soft X-Ray Ionization and Absorption , 2001, astro-ph/0109236.

[27]  Andrew King,et al.  Accretion Power in Astrophysics: Contents , 2002 .

[28]  M. Shara,et al.  Spatially Resolved STIS Spectra of WR + OB Binaries with Colliding Winds , 2001, astro-ph/0111496.

[29]  Karel A. van der Hucht,et al.  The VIIth catalogue of galactic Wolf–Rayet stars , 2001 .

[30]  G. Dubus,et al.  Precessing warped accretion discs in X‐ray binaries , 2000, astro-ph/0009264.

[31]  S. Kitamoto,et al.  Changes in the Long-Term Intensity Variations in Cygnus X-2 and LMC X-3 , 2000, astro-ph/0002219.

[32]  J. Fabregat,et al.  The Be Phenomenon in Early-Type Stars , 2000 .

[33]  John Scott Drilling,et al.  in Allen''''s Astrophysical Quantities , 2000 .

[34]  Myron A Smith.  The Be Phenomenon in Early‐Type Stars: IAU Colloquium 175 , 1999 .

[35]  D. Vanbeveren,et al.  The WR and O-type star population predicted by massive star evolutionary synthesis , 1998 .

[36]  K. Ishibashi,et al.  The relationship between two periodicities observed in Eta Carinae , 1998 .

[37]  I. McLean,et al.  A K-Band Spectral Atlas of Wolf-Rayet Stars , 1997 .

[38]  M. Rieke,et al.  A spectral atlas of hot, luminous stars at 2 microns , 1996 .

[39]  C. Day,et al.  Ginga observations of Centaurus X-3 , 1992 .

[40]  R. McCray,et al.  X-rays from colliding stellar winds , 1990 .

[41]  S. Baliunas,et al.  A Prescription for period analysis of unevenly sampled time series , 1986 .

[42]  D. Raine,et al.  Accretion power in astrophysics , 1985 .

[43]  Walter H. G. Lewin,et al.  X-ray binaries. , 1976 .

[44]  H. Friedman.  The X-Ray Universe , 1967 .