Spectral Analysis of the 2019 and 2022 Outbursts of SAX J1808.4-3658

Abstract

The accreting millisecond pulsar SAX J1808.4-3658 went into outburst from July to November in 2019 and August to October in 2022, which were observed by \textit{NICER} and \textit{NuSTAR}. In this paper, we first present the light curve for both outbursts using \textit{NICER} data. Several thermonuclear bursts occurred during these outbursts. We analyze the evolution of the spectra of two thermonuclear bursts that took place during the 2019 \textit{NuSTAR} observation. We proceed by analyzing the combined broad-band spectrum using \textit{NICER} and \textit{NuSTAR} for the first time for this source. We jointly modeled the combined quiescent spectra of both outbursts with a self-consistent reflection component. In our best-fit model, we find evidence of reflection, consistently constrain the inclination to 72°${}_{-4°}^{+1°}$\, considering this reflection, and identify a 1 keV feature during persistent emission.

References in corpus (30)

• On the Absorption of X-rays in the Interstellar Medium
• The Nuclear Spectroscopic Telescope Array (NuSTAR) Mission
• Broad-band gamma-ray and X-ray spectra of NGC 4151 and their implications for physical processes and geometry
• Thermonuclear (type-I) X-ray bursts observed by the Rossi X-ray Timing Explorer
• Improved Reflection Models of Black-Hole Accretion Disks: Treating the Angular Distribution of X-rays
• The May 1989 outburst of the Soft X-ray Transient GS 2023+338 (V404 Cyg)
• Broad iron lines in Active Galactic Nuclei
• The Properties of X-Ray and Optical Light Curves of X-Ray Novae
• Photospheric radius expansion X-ray bursts as standard candles
• Helium-rich thermonuclear bursts and the distance to the accretion-powered millisecond pulsar SAX J1808.4-3658
• A Brown Dwarf Companion for the Accreting Millisecond Pulsar SAX J1808.4-3658
• XMM-Newton detects a relativistically broadened iron line in the spectrum of the ms X-ray pulsar SAX J1808.4-3658
• Accretion, Outflows, and Winds of Magnetized Stars
• A NICER thermonuclear burst from the millisecond X-ray pulsar SAX J1808.4-3658
• Detection of Reflection Features in the Neutron Star Low-Mass X-ray Binary Serpens X-1 with NICER
• 1 Hz flaring in SAX J1808.4--3658: flow instabilities near the propeller stage
• The accretion flow to the intermittent accreting ms pulsar, HETE J1900.1-2455, as observed by XMM-Newton and RXTE
• The broad-band power spectrum of SAX J1808.4-3658
• The erratic luminosity behavior of SAX J1808.4-3658 during its 2000 outburst
• The Reflares and Outburst Evolution in the Accreting Millisecond Pulsar SAX J1808.4-3658: a Disk Truncated Near Co-rotation?
• NuSTAR and XMM-Newton broad-band spectrum of SAX J1808.4-3658 during its latest outburst in 2015
• Enhanced optical activity 12 days before X-ray activity, and a 4 day X-ray delay during outburst rise, in a low-mass X-ray binary
• A Bayesian Approach to Matching Thermonuclear X-ray Burst Observations with Models
• The aperiodic X-ray variability of the accreting millisecond pulsar SAX J1808.4-3658
• Probing jet launching in neutron star X-ray binaries: the variable and polarized jet of SAX J1808.4-3658
• The AstroSat observation of accreting millisecond X-ray pulsar SAX J1808.4-3658 during its 2019 outburst
• Evolution of accretion disc reflection spectra due to a Type I X-ray burst
• The 2019 outburst of AMXP SAX J1808.4-3658 and radio follow up of MAXI J0911-655 and XTE J1701-462
• The aperiodic timing behaviour of the accretion-driven millisecond pulsar SAX J1808.4-3658
• Hydrogen-triggered X-ray Bursts from SAX J1808.4-3658? The Onset of Nuclear Burning