SUZAKU OBSERVES WEAK FLARES FROM IGR J17391-3021 REPRESENTING A COMMON LOW-ACTIVITY STATE IN THIS SUPERGIANT FAST X-RAY TRANSIENT

Journal Article · Thu Jan 20 04:00:00 EST 2011 · Astrophysical Journal

DOI:https://doi.org/10.1088/0004-637X/727/1/59· OSTI ID:21567591

Bodaghee, A; Tomsick, J A ^[1]; Rodriguez, J; Chaty, S ^[2]; Pottschmidt, K ^[3]; Walter, R ^[4]; Romano, P ^[5]

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1. Space Sciences Laboratory, 7 Gauss Way, University of California, Berkeley, CA 94720 (United States)
2. Laboratoire AIM, CEA/IRFU-Universite Paris Diderot-CNRS/INSU, CEA DSM/IRFU/SAp, Centre de Saclay, F-91191 Gif-sur-Yvette (France)
3. CRESST and NASA Goddard Space Flight Center, Astrophysics Science Division, Code 661, Greenbelt, MD 20771 (United States)
4. INTEGRAL Science Data Centre, Universite de Geneve, Chemin d'Ecogia 16, CH-1290 Versoix (Switzerland)
5. INAF, Istituto di Astrofisica Spaziale e Fisica Cosmica, Via U. La Malfa 153, I-90146 Palermo (Italy)

We present an analysis of a 37 ks observation of the supergiant fast X-ray transient IGR J17391-3021 (= XTE J1739-302) gathered with Suzaku. The source evolved from quiescence to a low-activity level culminating in three weak flares lasting {approx}3 ks each in which the peak luminosity is only a factor of five times that of the pre-flare luminosity. The minimum observed luminosity was 1.3 x 10{sup 33} erg s{sup -1}(d/2.7 kpc){sup 2} in the 0.5-10 keV range. The weak flares are accompanied by significant changes in the spectral parameters including a column density (N{sub H} =(4.1{sup +0.4}{sub -0.5}) x 10{sup 22} cm{sup -2}) that is {approx}2-9 times the absorption measured during quiescence. Accretion of obscuring clumps of stellar wind material can explain both the small flares and the increase in N{sub H}. Placing this observation in the context of the recent Swift monitoring campaign, we find that weak-flaring episodes, or at least epochs of enhanced activity just above the quiescent level but well below the moderately bright or high-luminosity outbursts, represent more than 60% {+-} 5% of all observations in the 0.5-10 keV energy range making this the most common state in the emission behavior of IGR J17391-3021.

• OSTI ID: 21567591
• Journal Information: Astrophysical Journal, Journal Name: Astrophysical Journal Journal Issue: 1 Vol. 727; ISSN ASJOAB; ISSN 0004-637X
• Country of Publication: United States
• Language: English

Related Subjects

79 ASTRONOMY AND ASTROPHYSICS
EMISSION
EVOLUTION
GIANT STARS
LUMINOSITY
OPTICAL PROPERTIES
PHYSICAL PROPERTIES
STAR ACCRETION
STAR EVOLUTION
STARS
STELLAR ACTIVITY
STELLAR WINDS
SUPERGIANT STARS