OBSERVATIONS OF THE HIGH-MASS X-RAY BINARY A 0535+26 IN QUIESCENCE

Journal Article · Mon Jun 10 00:00:00 EDT 2013 · Astrophysical Journal

DOI:https://doi.org/10.1088/0004-637X/770/1/19· OSTI ID:22127176

Rothschild, Richard; Markowitz, Alex; Hemphill, Paul ^[1]; Caballero, Isabel ^[2]; Pottschmidt, Katja ^[3]; Kuehnel, Matthias; Wilms, Joern ^[4]; Fuerst, Felix ^[5]; Doroshenko, Victor ^[6]; Camero-Arranz, Ascension ^[7]

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1. University of California, San Diego, Center for Astrophysics and Space Sciences, 9500 Gilman Dr., La Jolla, CA 92093-0424 (United States)
2. CEA Saclay, DSM/IRFU/SAp -UMR AIM (7158) CNRS/CEA/Universite P. Diderot, Orme des Merisiers, Bat. 709, F-91191 Gif-sur-Yvette (France)
3. CRESST, UMBC, and NASA GSFC, Code 661, Greenbelt, MD 20771 (United States)
4. Dr. Karl-Remeis-Sternwarte and ECAP, Sternwartstr. 7, D-96049 Bamberg (Germany)
5. Space Radiation Lab, MC 290-17 Cahill, California Institute of Technology, 1200 E. California Blvd, Pasadena, CA 91125 (United States)
6. Institut fuer Astronomie und Astrophysik, Universitaet Tuebingen, Sand 1, D-72076 Tuebingen (Germany)
7. Institut de Ciencies de l'Espai, (IEEC-CSIC), Campus UAB, Fac. de Ciencies, Torre C5, parell, 2a planta, E-08193 Barcelona (Spain)

We have analyzed three observations of the high-mass X-ray binary A 0535+26 performed by the Rossi X-Ray Timing Explorer (RXTE) three, five, and six months after the last outburst in 2011 February. We detect pulsations only in the second observation. The 3-20 keV spectra can be fit equally well with either an absorbed power law or absorbed thermal bremsstrahlung model. Reanalysis of two earlier RXTE observations made 4 yr after the 1994 outburst, original BeppoSAX observations 2 yr later, reanalysis of four EXOSAT observations made 2 yr after the last 1984 outburst, and a recent XMM-Newton observation in 2012 reveal a stacked, quiescent flux level decreasing from {approx}2 to <1 Multiplication-Sign 10{sup -11} erg cm{sup -2} s{sup -1} over 6.5 yr after outburst. The detection of pulsations during half of the quiescent observations would imply that accretion onto the magnetic poles of the neutron star continues despite the fact that the circumstellar disk may no longer be present. The accretion could come from material built up at the corotation radius or from an isotropic stellar wind.

• OSTI ID: 22127176
• Journal Information: Astrophysical Journal, Vol. 770, Issue 1; Other Information: Country of input: International Atomic Energy Agency (IAEA); ISSN 0004-637X
• Country of Publication: United States
• Language: English

Related Subjects

79 ASTROPHYSICS
COSMOLOGY AND ASTRONOMY
BREMSSTRAHLUNG
DETECTION
KEV RANGE
MASS
NEUTRON STARS
NEUTRONS
PULSARS
PULSATIONS
SPECTRA
STELLAR WINDS
X RADIATION