Deep Search for Gamma-Ray Emission from the Accreting X-Ray Pulsar 1A 0535+262

Hou, X.; Zhang, W.; Torres, D. F.; Ji, Long; Li, Jian

doi:10.3847/1538-4357/acaec7

Cited by 6 publications

(6 citation statements)

References 67 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…On the other hand, in a similar data analysis presented by Hou et al (2023) and based on about 13 years of Fermi/LAT observations, A0535+26 is not detected. Hou et al (2023) suggest that the difference between their findings and those reported by Harvey et al (2022b) might be due to the different size of the fitting regions adopted, as well as the treatment of the spectral index, which was fixed to different values in Hou et al (2023) while in Harvey et al (2022b) it was left free to vary. VERITAS observed A0535+26 at VHEs during the 2009 and 2020 giant X-ray outbursts.…”

Section: A0535+26supporting

confidence: 55%

Modelling the expected very high energy γ-ray emission from accreting neutron stars in X-ray binaries

Ducci,

Romano,

Vercellone

et al. 2023

Monthly Notices of the Royal Astronomical Society

View full text Add to dashboard Cite

The detection of γ −ray emission from accreting pulsars in X-ray binaries (XRBs) has long been sought after. For some high-mass X-ray binaries (HMXBs), marginal detections have recently been reported. Regardless of whether these will be confirmed or not, future telescopes operating in the γ −ray band could offer the sensitivity needed to achieve solid detections and possibly spectra. In view of future observational advances, we explored the expected emission above 10 GeV from XRBs, based on the Cheng & Ruderman model, where γ −ray photons are produced by the decay of π0 originated by protons accelerated in the magnetosphere of an accreting pulsar fed by an accretion disc. We improved this model by considering, through Monte Carlo simulations, the development of cascades inside of and outside the accretion disc, taking into account pair and photon production processes that involve interaction with nuclei, X-ray photons from the accretion disc, and the magnetic field. We produced grids of solutions for different input parameter values of the X-ray luminosity (Lx), magnetic field strength (B), and for different properties of the region where acceleration occurs. We found that the γ −ray luminosity spans more than five orders of magnitude, with a maximum of ∼1035 erg s−1. The γ −ray spectra show a large variety of shapes: some have most of the emission below ∼100 GeV, others are harder (emission up to 10−100 TeV). We compared our results with Fermi/LAT and VERITAS detections and upper-limits of two HMXBs: A0535+26 and GRO J1008−57. More consequential comparisons will be possible when more sensitive instruments will be operational in the coming years.

show abstract

Section: A0535+26supporting

confidence: 55%

Modelling the expected very high energy γ-ray emission from accreting neutron stars in X-ray binaries

Ducci,

Romano,

Vercellone

et al. 2023

Monthly Notices of the Royal Astronomical Society

View full text Add to dashboard Cite

show abstract

“…The pulse profiles obtained for different observations were aligned according to an averaged template of 30-120 keV (which is relatively simple and stable) with the FFTFIT routine (Taylor 1992). 7 The evolution of pulse profiles has been shown in Figure 2 in Wang et al (2022), and the detailed spin history is given in Table 2 in Hou et al (2023). We note that the alignment may not be perfect owing to variations in the pulse profile, and some phase offsets are expected in practice.…”

Section: Available Data and Data Selectionmentioning

confidence: 97%

Beam Pattern Evolution of Accreting X-Ray Pulsar 1A 0535+262 during Its 2020 Giant Outburst

et al. 2023

ApJ

Self Cite

View full text Add to dashboard Cite

We report on pulse profile decomposition analysis of bright transient X-ray pulsar 1A 0535+262 using broadband Insight-HXMT observations during a giant outburst of the source in 2020. We show that the observed pulse profile shape can be described in terms of a combination of two symmetric single-pole contributions for a wide range of energies and luminosities for a fixed geometry defining the basic geometry of the pulsar. This corresponds to a slightly distorted dipole magnetic field, i.e., one pole has to be offset by ∼12° from the antipodal position of the other pole. We reconstruct the intrinsic beam patterns of the pulsar assuming that the geometry is recovered from the decomposition analysis, and we find evidence for a transition between “pencil” and “fan” beams in energy ranges above the cyclotron line energy, which can be interpreted as a transition from sub- to supercritical accretion regimes associated with the onset of an accretion column. At lower energies, however, the beam pattern appears to be more complex and contains a substantial “fan” beam and an additional “pencil” beam component at all luminosities. The latter is not related to the accretion rate and is stronger in the fading phase of the outburst. We finally discuss the results in the context of other observational and theoretical findings earlier reported for the source in the literature.

show abstract

“…The PolarLight data alone do not allow us to find the pulsar spin period and fold the lightcurve. We thereby rely on the ephemeris computed with HXMT observations (Kong et al 2022;Hou et al 2023). Both the barycentric correction and binary motion are taken into account.…”

Section: Observations and Analysismentioning

confidence: 99%

“…PolarLight observed 1A 0535+262 from November 15 to December 12, 2020, with a total effective exposure of 69 ks. The emission state and pulsar ephemeris are adopted from HXMT observations with obsIDs P0304099001-18 and P0314316001-15 (Kong et al 2021(Kong et al , 2022Hou et al 2023); details about the HXMT data reduction can be found in Kong et al (2021). The lightcurves of the outburst measured with the two instruments are displayed in Figure 1.…”

Section: Observations and Analysismentioning

confidence: 99%

A Significant Detection of X-ray Polarization in Sco X-1 with PolarLight and Constraints on the Corona Geometry

Long

Feng

et al. 2022

ApJL

View full text Add to dashboard Cite

We report the detection of X-ray polarization in the neutron-star low-mass X-ray binary Scorpius (Sco) X-1 with PolarLight. The result is energy-dependent, with a nondetection in 3–4 keV but a 4σ detection in 4–8 keV; it is also flux-dependent in the 4–8 keV band, with a nondetection when the source displays low fluxes but a 5σ detection during high fluxes, in which case we obtain a polarization fraction of 0.043 ± 0.008 and a polarization angle of 52.°6 ± 5.°4. This confirms a previous marginal detection with OSO-8 in the 1970s and marks Sco X-1 as the second astrophysical source with a significant polarization measurement in the keV band. The measured polarization angle is in line with the jet orientation of the source on the sky plane (54°), which is supposedly the symmetry axis of the system. Combining previous spectral analysis, our measurements suggest that an optically thin corona is located in the transition layer under the highest accretion rates, and disfavor the extended accretion disk corona model.

show abstract

Deep Search for Gamma-Ray Emission from the Accreting X-Ray Pulsar 1A 0535+262

Cited by 6 publications

References 67 publications

Modelling the expected very high energy γ-ray emission from accreting neutron stars in X-ray binaries

Modelling the expected very high energy γ-ray emission from accreting neutron stars in X-ray binaries

Beam Pattern Evolution of Accreting X-Ray Pulsar 1A 0535+262 during Its 2020 Giant Outburst

A Significant Detection of X-ray Polarization in Sco X-1 with PolarLight and Constraints on the Corona Geometry

Contact Info

Product

Resources

About