Discovery of the 5 keV cyclotron line followed by three harmonics in SwiftJ1626.6-5156
arXiv:2106.09514 · doi:10.3847/2041-8213/ac0c15
Abstract
We report on observations of the Be/X-ray binary system SwiftJ1626.6-5156 performed with NuSTAR during a short outburst in March 2021, following its detection of by the MAXI monitor and Spektrum-Roentgen-Gamma (SRG) observatory. Our analysis of the broadband X-ray spectrum of the source confirms the presence of two absorption-like features at energies ~9 and ~17 keV previously reported in literature and interpreted as the fundamental cyclotron resonance scattering feature (CRSF) and its first harmonic (based on RXTE data). The better sensitivity and energy resolution of NuSTAR, combined with the low energy coverage of NICER, allowed us to detect two additional absorption-like features at ~4.9 keV and ~13 keV. We conclude, therefore, that in total four cyclotron lines are observed in the spectrum of SwiftJ1626.6-5156: the fundamental CRSF at ~4.9 keV and three higher spaced harmonics. This discovery makes SwiftJ1626.6-5156 the second accreting pulsar, after 4U0115+63, whose spectrum is characterized by more than three lines of a cyclotronic origin, and implies the source has the weakest confirmed magnetic field among all X-ray pulsars B~4E11 G. This discovery makes SwiftJ1626.6-5156 one of prime targets for the upcoming X-ray polarimetry missions covering soft X-ray band such as IXPE and eXTP.
References in corpus (6)
- Estimating distances from parallaxes. V: Geometric and photogeometric distances to 1.47 billion stars in Gaia Early Data Release 3
- 4U 0115+63 from RXTE and INTEGRAL Data: Pulse Profile and Cyclotron Line Energy
- Transient X-ray pulsar V0332+53: pulse phase-resolved spectroscopy and the reflection model
- GRO J1744-28: an intermediate B-field pulsar in a low mass X-ray binary
- Physics and astrophysics of strong magnetic field systems with eXTP
- Bright flares from the X-ray pulsar SWIFT J1626.6-5156
Cited by in corpus (4)
- Discovery of Two Cyclotron Resonance Scattering Features in X-ray Pulsar Cen X-3 by Insight-HXMT
- A high-mass X-ray binary pulsar 4U 1907+09 with multiple absorption-line features in the spectrum
- Spectral and timing analysis of BeXRB eRASSU J050810.4-660653 recently discovered in the Large Magellanic Cloud (LMC)
- Spectral and Timing properties of the recently discovered Be/X-ray pulsar eRASSUJ 052914.9-662446