Spectral evolution of X-ray pulsar 4U 1901+03 during the 2019 outburst based on Insight-HXMT and NuSTAR observations
arXiv:2005.14555 · doi:10.1051/0004-6361/202038531
Abstract
We report on a detailed spectral analysis of emission from X-ray pulsar 4U 1901+03 using data obtained by the Insight-HXMT and NuSTAR observatories during the 2019 outburst of the source. Thanks to the extensive coverage of the outburst by Insight-HXMT, we were able to investigate the spectral evolution of the source as a function of flux, and compare these results to the previous reports, focusing on the properties of a putative absorption feature at around 10 keV. In particular, we demonstrate that the broadband X-ray continuum of 4U 1901+03 can be well described with a two-component continuum model without an absorption line at 10 keV, which casts doubt on its interpretation as a cyclotron line. The high quality of the data also allowed us to perform both phase-averaged and phase-resolved spectral analyses as a function of luminosity. Finally, we performed a detailed investigation of another absorption feature in the spectrum of the source around 30 keV recently reported in the NuSTAR data. We show that this feature appears to be significantly detected both in phase-averaged and phase-resolved spectra irrespective of the continuum model.
arXiv comment12 pages, 11 figures, 5 tables, revised version accepted for publication in A&A
References in corpus (41)
- On the Absorption of X-rays in the Interstellar Medium
- The Nuclear Spectroscopic Telescope Array (NuSTAR) Mission
- Atomic Data for Astrophysics. II. New Analytic Fits for Photoionization Cross Sections of Atoms and Ions
- Estimating distances from parallaxes IV: Distances to 1.33 billion stars in Gaia Data Release 2
- Calibration of X-ray absorption in our Galaxy
- Statistics: Handle with Care, Detecting Multiple Model Components with the Likelihood Ratio Test
- Sonic-Point Model of Kilohertz Quasi-Periodic Brightness Oscillations in Low-Mass X-ray Binaries
- Galactic Reddening in 3D from Stellar Photometry - An Improved Map
- Magnetic Fields of Accreting X-Ray Pulsars with the Rossi X-Ray Timing Explorer
- Overview to the Hard X-ray Modulation Telescope (Insight-HXMT) Satellite
- Thermal and Bulk Comptonization in Accretion-Powered X-Ray Pulsars
- Spectral Formation in Accreting X-Ray Pulsars: Bimodal Variation of the Cyclotron Energy with Luminosity
- Calibration of the NuSTAR High Energy Focusing X-ray Telescope
- Cyclotron lines in highly magnetized neutron stars
- The critical accretion luminosity for magnetized neutron stars
- V0332+53 in the outburst of 2004--2005: luminosity dependence of the cyclotron line and pulse profile
- The Medium Energy (ME) X-ray telescope onboard the Insight-HXMT astronomy satellite
- On Timing and Spectral Characteristics of the X-ray Pulsar 4U 0115+63: Evolution of the Pulsation Period and the Cyclotron Line Energy
- Hard Spectra of X-Ray Pulsars from INTEGRAL Data
- Discovery of a Cyclotron Resonant Scattering Feature in the RXTE Spectrum of 4U 0352+309 (X Per)
- Cyclotron Line Variability
- The hard X-ray emission of X Per
- 4U 0115+63: phase lags and cyclotron resonant scattering
- Dramatic spectral transition of X-ray pulsar GX 304-1 in low luminous state
- Cyclotron emission, absorption, and the two faces of X-ray pulsar A 0535+262
- Strong outburst activity of the X-ray pulsar X Persei during 2001-2011
- Numerical solution of the radiative transfer equation: X-ray spectral formation from cylindrical accretion onto a magnetized neutron star
- Spectrum formation in X-ray pulsars at very low mass accretion rate: Monte-Carlo approach
- X-ray emission from magnetized neutron star atmospheres at low mass accretion rates. I. Phase-averaged spectrum
- Discovery of pulsations in the X-ray transient 4U 1901+03
- LUNASKA Experiment Observational Limits on UHE Neutrinos from Centaurus A and the Galactic Center
- Dynamical and Radiative Properties of X-ray Pulsar Accretion Columns: Phase-Averaged Spectra
- Variations in the Cyclotron Resonant Scattering Features during 2011 outburst of 4U 0115+63
- Accretion regimes in the X-ray pulsar 4U 1901+03
- SRG/ART-XC and NuSTAR observations of the X-ray pulsar GRO J1008-57 in the lowest luminosity state
- Three-dimensional modelling of accretion columns: spatial asymmetry and self-consistent simulations
- Evolution of timing and spectral characteristics of 4U 1901+03 during its 2019 outburst using the Swift and NuSTAR observatories
- Flares, Broadening of the Pulse frequency peak, and Quasi Periodic Oscillations in the Transient X-ray Pulsar 4U 1901+03
- Switches between accretion structures during flares in 4U 1901+03
- In-flight calibration of the Insight-Hard X-ray Modulation Telescope
- Phase-resolved spectral analysis of 4U 1901+03 during its outburst