The faint 2005 hard state outburst of Aquila X-1 seen by INTEGRAL and RXTE

Abstract

We report on the spectral analysis of RXTE and INTEGRAL data of the 2005 April outburst of the transient Atoll source Aql X-1. Although this outburst is one of the faintest ever detected for this source in the soft X-rays (RXTE/ASM), one of our INTEGRAL observations, taken close to the soft X-ray peak, shows that the source flux was quite high, with a 20-200 keV flux of 2.05 x 10^-9 erg cm^-2 s^-1. On this occasion we detect the source up to 150 keV for the first time. We compare and discuss the similarity of the source behavior with that of black hole transients especially XTE J1550-564.

arXiv comment4 pages 2 figures, Accepted for publication in A&A as a RESEARCH NOTE

References in corpus (13)

• ISGRI: the INTEGRAL Soft Gamma-Ray Imager
• Correlated X-ray Spectral and Timing Behavior of the Black Hole Candidate XTE J1550-564: A New Interpretation of Black Hole States
• Quiescent Thermal Emission from the Neutron Star in Aql X-1
• Spectral evolution of the microquasar XTE J1550-564 over its entire 2000 outburst
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• Spectral Fits to the 1999 Aql X-1 Outburst Data
• An X-ray Timing Study of XTE J1550--564: Evolution of the Low Frequency QPO for the Complete 2000 Outburst
• INTEGRAL and XMM-Newton observations of the X-ray pulsar IGR J16320-4751/AX J1631.9-4752
• XTE J1550-564: INTEGRAL Observations of a Failed Outburst
• Evolution of Spectral States of Aql X-1 during the 2000 Outburst
• Constraints on jet X-ray emission in low/hard state X-ray binaries
• Distribution of the Galactic Bulge emission at |b|>2deg according to the RXTE Galactic Center scans
• Hard X-ray Flares Preceding Soft X-ray Outbursts in Aquila X-1: A Link between Neutron Star and Black Hole State Transitions

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• State Transitions in Bright Galactic X-ray Binaries: Luminosities Span by Two Orders of Magnitude
• The disc-jet coupling in the neutron star X-ray binary Aquila X-1
• Two years of INTEGRAL monitoring of GRS 1915+105 Part 1: multiwavelength coverage with INTEGRAL, RXTE, and the Ryle radio Telescope
• Outburst Morphology in the Soft X-ray Transient Aquila X-1
• A Hard-to-Soft State Transition during A Luminosity Decline of Aquila X-1
• The discovery outburst of the X-ray transient IGR J17497-2821 observed with RXTE and ATCA
• The 2015 hard-state only outburst of GS 1354-64
• The INTEGRAL view of the pulsating hard X-ray sky: from accreting and transitional millisecond pulsars to rotation-powered pulsars and magnetars
• Catalog of outbursts of neutron star LMXBs
• The 2008 outburst of IGR J17473--2721: evidence for a disk corona?
• The failed state transition of the ATOLL source GRS 1724-308
• An enigmatic hump around 30 keV in Suzaku spectra of Aquila X-1 in the Hard State