The reawakening of the sleeping X-ray pulsar XTE J1946+274

Abstract

We report on a series of outbursts of the high mass X-ray binary XTE J1946+274 in 2010/2011 as observed with INTEGRAL, RXTE, and Swift. We discuss possible mechanisms resulting in the extraordinary outburst behavior of this source. The X-ray spectra can be described by standard phenomenological models, enhanced by an absorption feature of unknown origin at about 10 keV and a narrow iron K alpha fluorescence line at 6.4 keV, which are variable in flux and pulse phase. We find possible evidence for the presence of a cyclotron resonance scattering feature at about 25 keV at the 93% level. The presence of a strong cyclotron line at 35 keV seen in data from the source's 1998 outburst and confirmed by a reanalysis of these data can be excluded. This result indicates that the cyclotron line feature in XTE J1946+274 is variable between individual outbursts.

9 pages, 8 figures, accepted for publication in A&A

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Cited by in corpus (18)

• GRO J1008-57: an (almost) predictable transient X-ray binary
• Magnetic fields of neutron stars in X-ray binaries
• A double-peaked outburst of A 0535+26 observed with INTEGRAL, RXTE, and Suzaku
• Measurements of Cyclotron Features and Pulse Periods in the High-Mass X-Ray Binaries 4U 1538-522 and 4U 1907+09 with INTEGRAL
• Accretion regimes in the X-ray pulsar 4U 1901+03
• Simultaneous NuSTAR/Chandra observations of the Bursting Pulsar GRO J1744-28 during its third reactivation
• Pulse phase dependent variations of the cyclotron absorption features of the accreting pulsars A 0535+26, XTE J1946+274 and 4U 1907+09 with Suzaku
• The Transient Accereting X-Ray Pulsar XTE J1946+274: Stability of the X-Ray Properties at Low Flux and Updated Orbital Solution
• Evidence for an Evolving Cyclotron Line Energy in 4U 1538-522
• Activity from the Be/X-ray binary system V0332+53 during its intermediate-luminosity outburst in 2008
• BeppoSAX observations of XTE J1946+274
• Catalog of the Galactic population of X-ray pulsars in High-mass X-ray binary systems
• The giant outburst of 4U 0115+634 in 2011 with Suzaku and RXTE
• Two giant outbursts of V 0332+53 observed with INTEGRAL
• Detection of a large Be circumstellar disk during X-ray quiescence of XTE J1946+274
• Precursors and Outbursts of A 0535+26 in 2009-2011 observed by the MAXI/GSC and the Swift/BAT
• Study of the X-ray Pulsar XTE J1946+274 with NuSTAR
• AstroSat observations of the Be/X-ray binary XTE J1946+274 during 2018 and 2021 outbursts