A Chandra Observation of the Neutron Star X-Ray Transient and Eclipsing Binary MXB 1659–29 in Quiescence

After almost 2.5 yr of actively accreting, the neutron star X-ray transient and eclipsing binary MXB 1659-29 returned to quiescence in 2001 September. We report on a Chandra observation of this source taken a little over a month after this transition. The source was detected at an unabsorbed 0.5-10 keV flux of only (2.7-3.6) × 10-13 ergs cm-2 s-1, which implies a 0.5-10 keV X-ray luminosity of approximately (3.2-4.3) × 1033 (d/10 kpc)2 ergs s-1, with d the distance to the source in kiloparsecs. Its spectrum had a thermal shape and could be well fitted by either a blackbody with a temperature kT of ~0.3 keV or a neutron star atmosphere model with a kT of ~0.1 keV. The luminosity and spectral shape of MXB 1659-29 are very similar to those observed of the other neutron star X-ray transients when they are in their quiescent state. The source was variable during our observation, exhibiting a complete eclipse of the inner part of the system by the companion star. Dipping behavior was observed before the eclipse, likely due to obscuration by an extended feature in the outer part of a residual accretion disk. We discuss our observation in the context of the cooling neutron star model proposed to explain the quiescent properties of neutron star X-ray transients.

[1]  J. Grindlay,et al.  X-Ray Studies of Two Neutron Stars in 47 Tucanae: Toward Constraints on the Equation of State , 2003, astro-ph/0301235.

[2]  B. Krauskopf,et al.  Proc of SPIE , 2003 .

[3]  M. Nowak,et al.  Hiding in Plain Sight: Chandra Observations of the Quiescent Neutron Star 4U 2129+47 in Eclipse , 2002, astro-ph/0204503.

[4]  S. Corbel,et al.  A Closer Look at the Soft X-Ray Transient X1608–52: Long-Term Optical and X-Ray Observations , 2001, astro-ph/0112465.

[5]  Michael R. Garcia,et al.  The X-Ray Spectra of Black Hole X-Ray Novae in Quiescence as Measured by Chandra , 2001, astro-ph/0111134.

[6]  R. Wijnands,et al.  The Burst Behavior of the Eclipsing Low-Mass X-Ray Binary MXB 1659–298 , 2001, astro-ph/0109193.

[7]  L. Bildsten,et al.  Crustal Emission and the Quiescent Spectrum of the Neutron Star in KS 1731–260 , 2001, astro-ph/0108125.

[8]  Mit,et al.  Identification of the Optical and Quiescent Counterparts to the Bright X-Ray Transient in NGC 6440 , 2001, astro-ph/0111213.

[9]  T. Oosterbroek,et al.  An XMM-Newton study of the X-ray binary MXB 1659-298 and the discovery of narrow X-ray absorption lines , 2001, astro-ph/0109417.

[10]  T. Oosterbroek,et al.  A BeppoSAX observation of Her X-1 during the first main-on after an anomalous low-state: Evidence for rapid spin-down , 2001, astro-ph/0106193.

[11]  E. Morgan,et al.  The Erratic Luminosity Behavior of SAX J1808.4–3658 during Its 2000 Outburst , 2001, astro-ph/0105446.

[12]  L. Bildsten,et al.  Quiescent Thermal Emission from the Neutron Star in Aquila X-1 , 2001, astro-ph/0105319.

[13]  D. Chakrabarty,et al.  Millisecond Oscillations and Photospheric Radius Expansion in Thermonuclear X-Ray Bursts , 2001, astro-ph/0105042.

[14]  J. Lasota.  The disc instability model of dwarf novae and low-mass X-ray binary transients , 2001, astro-ph/0102072.

[15]  L. Bildsten,et al.  The Quiescent X-Ray Spectrum of the Neutron Star in Centaurus X-4 Observed with Chandra/ACIS-S , 2000, astro-ph/0012400.

[16]  K. Menou,et al.  The Quiescent Emission Spectrum of Centaurus X-4 and Other X-Ray Transients Containing Neutron Stars , 2000, astro-ph/0010430.

[17]  R. Wijnands,et al.  Discovery of Nearly Coherent Oscillations with a Frequency of ~567 Hz during Type I X-Ray Bursts of the X-Ray Transient and Eclipsing Binary X1658–298 , 2000, astro-ph/0008526.

[18]  F. Verbunt.  A census with ROSAT of low-luminosity X-ray sources in globular clusters , 2000, astro-ph/0012261.

[19]  R. Wijnands,et al.  The Decrease in X-Ray Flux of the Accretion-powered Millisecond Pulsar SAX J1808.4–3658 in Quiescence Detected by ASCA , 2000, astro-ph/0009295.

[20]  Margarita Karovska,et al.  Initial performance of the aspect system on the Chandra Observatory: postfacto aspect reconstruction , 2000, Astronomical Telescopes and Instrumentation.

[21]  L. Stella,et al.  On the Bolometric Quiescent Luminosity and Luminosity Swing of Black Hole Candidate and Neutron Star Low-Mass X-Ray Transients , 2000, astro-ph/0005118.

[22]  C. Bailyn,et al.  The Reappearance of the Transient Low-Mass X-Ray Binary X1658–298 , 1999, astro-ph/9912480.

[23]  J. McClintock,et al.  HST/STIS UV Spectroscopy of Two Quiescent X-Ray Novae: A0620–00 and Centaurus X-4 , 1999, astro-ph/9907316.

[24]  L. Bildsten,et al.  A Method for Distinguishing between Transiently Accreting Neutron Stars and Black Holes, in Quiescence , 1999, astro-ph/9909319.

[25]  Kristen Menou,et al.  Black Hole and Neutron Star Transients in Quiescence , 1998, astro-ph/9810323.

[26]  L. Natalucci,et al.  Bursting sources in the Galactic Centre region , 1999 .

[27]  Yasuo Tanaka,et al.  ASCA Observations of Transient X-Ray Sources in Quiescence , 1998 .

[28]  L. Bildsten,et al.  Crustal Heating and Quiescent Emission from Transiently Accreting Neutron Stars , 1998, astro-ph/9807179.

[29]  M. Colpi,et al.  Aquila X-1 from Outburst to Quiescence: The Onset of the Propeller Effect and Signs of a Turned-on Rotation-powered Pulsar , 1998, astro-ph/9803303.

[30]  M. Livio,et al.  The Properties of X-Ray and Optical Light Curves of X-Ray Novae , 1997, astro-ph/9707138.

[31]  L. Cominsky,et al.  Complex outburst behaviour from the black hole candidate 4U1630—47 , 1997, astro-ph/9706135.

[32]  K. Koyama,et al.  A New Eclipsing X-Ray Burster near the Galactic Center: A Quiescent State of the Old Transient A1742—289 , 1996 .

[33]  N. Kawai,et al.  ASCA Observation of the Rapid Burster in Quiescence , 1996 .

[34]  R. Corbet.  Transient X-Ray Sources, Luminosity Gaps, and Neutron Star Densities , 1996 .

[35]  M. Colpi,et al.  Do quiescent soft X-ray transients contain millisecond radio pulsars? , 1994 .

[36]  S. Campana,et al.  The neutron stars of Soft X–ray Transients , 1993, astro-ph/9805079.

[37]  J. Dickey,et al.  H I in the Galaxy , 1990 .

[38]  L. Cominsky,et al.  Further observations of the eclipsing X-ray burst source MXB 1659-29 , 1989 .

[39]  Nicholas E. White,et al.  The Discovery of 3.8 Hour Periodic Intensity Dips and Eclipses from the Transient Low-Mass X-Ray Binary EXO 0748-676 , 1986 .

[40]  L. Cominsky,et al.  Discovery of a 7.1 hour period and eclipses from MXB 1659-29 , 1984 .

[41]  Saul A. Teukolsky,et al.  Black Holes, White Dwarfs, and Neutron Stars , 1983 .

[42]  L. Cominsky,et al.  Irregular X-ray variability in the transient X-ray burst source MXB 1659-29 , 1983 .

[43]  R. London,et al.  The noncompact binary X-ray source 4U 2129+47 , 1982 .

[44]  M. Johnston,et al.  Identification of the variable X-ray sources GX 339-4 and MXB 1659-29 by the scanning modulation collimator on HEAO 1 , 1979 .

[45]  H. Tananbaum,et al.  The fourth Uhuru catalog of X-ray sources. , 1978 .

[46]  H. Gursky,et al.  Identification of 4U 1651+39 with the BL Lacertae object Markarian 501 with the modulation collimator on HEAO 1 , 1978 .

[47]  G. Clark,et al.  Discovery of X-ray bursts from MXB 1728-34 , 1976 .

[48]  Ulrich Hopp,et al.  THE ASTRONOMICAL SOCIETY OF THE PACIFIC. , 1916, Science.