Outflows and spectral evolution in the eclipsing AMXP SWIFT J1749.4-2807 with NICER, XMM-Newton and NuSTAR

Abstract

The neutron star low-mass X-ray binary SWIFT J1749.4-2807 is the only known eclipsing accreting millisecond X-ray pulsar. In this manuscript we perform a spectral characterization of the system throughout its 2021, two-week-long outburst, analyzing 11 NICER observations and quasi-simultaneous XMM-Newton and NuSTAR single observations at the outburst peak. The broadband spectrum is well-modeled with a black body component with a temperature of $\sim$0.6 keV, most likely consistent with a hot spot on the neutron star surface, and a Comptonisation spectrum with power-law index $\Gamma \sim 1.9$, arising from a hot corona at $\sim$12 keV. No direct emission from the disc was found, possibly due to it being too cool. A high truncation radius for the disc, i.e., at $\sim$20--30 R${}_G$ , was obtained from the analysis of the broadened profile of the Fe line in the reflection component. The significant detection of a blue-shifted Fe XXVI absorption line at $\sim$7 keV indicates weakly relativistic X-ray disc winds, which are typically absent in the hard state of X-ray binaries. By comparing the low flux observed during the outburst and the one expected in a conservative mass-transfer, we conclude that mass-transfer in the system is highly non-conservative, as also suggested by the wind detection. Finally, using the Nicer spectra alone, we followed the system while it was fading to quiescence. During the outburst decay, as the spectral shape hardened, the hot spot on the neutron star surface cooled down and shrank, a trend which could be consistent with the pure power-law spectrum observed during quiescence.

15 pages, 9 figure; accepted for publication on MNRAS

References in corpus (36)

• Modelling the behaviour of accretion flows in X-ray binaries
• A Radio Pulsar/X-ray Binary Link
• Relativistic X-ray Lines from the Inner Accretion Disks Around Black Holes
• The Accretion Disk Wind in the Black Hole GRO J1655-40
• On why the Iron K-shell absorption in AGN is not a signature of the local Warm/Hot Intergalactic Medium
• Black hole-like hysteresis and accretion states in neutron star low mass X-ray binaries
• The First Swift Ultra-Violet/Optical Telescope GRB Afterglow Catalog
• Orbital Evolution of an Accreting Millisecond Pulsar: Witnessing the Banquet of a Hidden Black Widow?
• Hard-state accretion disk winds from black holes: the revealing case of MAXI J1820+070
• The Variable Quiescent X-ray Emission of the Neutron Star Transient XTE J1701-462
• General-Relativistic Simulations of Four States of Accretion onto Millisecond Pulsars
• An in-depth study of a neutron star accreting at low Eddington rate: On the possibility of a truncated disk and an outflow
• A Hard X-Ray Power-Law Spectral Cutoff in Centaurus X-4
• The nature of very faint X-ray binaries; hints from light curves
• A connection between accretion state and $\text{Fe K absorption}$ in an accreting neutron star: black hole-like soft state winds?
• On the Fe K absorption - accretion state connection in the Galactic center neutron star X-ray binary AX J1745.6-2901
• XMMU J174716.1-281048: a "quasi-persistent" very faint X-ray transient?
• Timing of the 2008 Outburst of SAX J1808.4-3658 with XMM-Newton: A Stable Orbital Period Derivative over Ten Years
• A persistent ultraviolet outflow from an accreting neutron star binary transient
• Thermal Disk Winds in X-ray Binaries: Realistic Heating and Cooling Rates Give Rise to Slow, but Massive Outflows
• On the timing properties of SAX J1808.4-3658 during its 2015 outburst
• Discovery of a new accreting millisecond X-ray pulsar in the globular cluster NGC 2808
• Chandra X-ray spectroscopy of a clear dip in GX 13+1
• Thermal and radiation driving can produce observable disk winds in hard-state X-ray binaries
• Hard-state optical wind during the discovery outburst of the black-hole X-ray dipper MAXI J1803-298
• Testing Rate Dependent corrections on timing mode EPIC-pn spectra of the accreting Neutron Star GX 13+1
• Photoionization instability of the Fe K absorbing plasma in the neutron star transient AX J1745.6-2901
• Indications of non-conservative mass-transfer in AMXPs
• NuSTAR low energy effective area correction due to thermal blanket tear
• New insights on the puzzling LMXB 1RXS J180408.9-342058: the intermediate state, the clocked type-I X-ray bursts and much more
• NICER Discovery of Millisecond X-ray Pulsations and an Ultracompact Orbit in IGR J17494-3030
• Potential cooling of an accretion-heated neutron star crust in the low-mass X-ray binary 1RXS J180408.9-342058
• Spectral analysis of the low-mass X-ray pulsar 4U 1822-371: Reflection component in a high-inclination system
• Chandra-HETGS Characterization of an Outflowing Wind in the accreting millisecond pulsar IGR J17591-2342
• Evidence of a non-conservative mass transfer for XTE J0929-314
• Evolution of the disc atmosphere in the X-ray binary MXB 1659-298, during its 2015-2017 outburst

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