Reflection and timing study of the transient black hole X-ray binary MAXI J1803-298 with NuSTAR

Abstract

The transient black hole X-ray binary MAXI J1803-298 was discovered on 2021 May 1, as it went into outburst from a quiescent state. As the source rose in flux it showed periodic absorption dips and fit the timing and spectral characteristics of a hard state accreting black hole. We report on the results of a Target-of-Opportunity observation with NuSTAR obtained near the peak outburst flux beginning on 2021 May 13, after the source had transitioned into an intermediate state. MAXI J1803-298 is variable across the observation, which we investigate by extracting spectral and timing products separately for different levels of flux throughout the observation. Our timing analysis reveals two distinct potential QPOs which are not harmonically related at 5.4+/-0.2 Hz and 9.4+/-0.3 Hz, present only during periods of lower flux. With clear relativistic reflection signatures detected in the source spectrum, we applied several different reflection models to the spectra of MAXI J1803-298. Here we report our results, utilizing high density reflection models to constrain the disk geometry, and assess changes in the spectrum dependent on the source flux. With a standard broken power-law emissivity, we find a near-maximal spin for the black hole, and we are able to constrain the inclination of the accretion disk at 75+/-2 degrees, which is expected for a source that has shown periodic absorption dips. We also significantly detect a narrow absorption feature at 6.91+/-0.06 keV with an equivalent width between 4 and 9 eV, which we interpret as the signature of a disk wind.

14 pages, 8 figures, accepted for publication (ApJ)

References in corpus (15)

• X-ray Properties of Black-Hole Binaries
• Relativistic X-ray Lines from the Inner Accretion Disks Around Black Holes
• The role of the reflection fraction in constraining black hole spin
• X-ray reflection in accreting stellar-mass black hole systems
• No Time for Dead Time: Timing analysis of bright black hole binaries with NuSTAR
• High Density Reflection Spectroscopy I. A case study of GX~339-4
• New Constraints on the Black Hole Low/Hard State Inner Accretion Flow with NuSTAR
• Reflection Modeling of the Black Hole Binary 4U~1630$-$47: the Disk Density and Returning Radiation
• A New Spin on an Old Black Hole: NuSTAR Spectroscopy of EXO 1846-031
• Hard-state optical wind during the discovery outburst of the black-hole X-ray dipper MAXI J1803-298
• AstroSat Observation of X-ray Dips and State Transition in the Black Hole Candidate MAXI J1803-298
• High-density disc reflection spectroscopy of low-mass active galactic nuclei
• The long-stable hard state of XTE J1752-223 and the disk truncation dilemma
• Discovery and Long-term Broadband X-ray monitoring of Galactic Black Hole Candidate MAXI J1803-298
• A NuSTAR and Swift View of the Hard State of MAXI J1813-095