Discovery and Identification of MAXI J1621-501 as a Type I X-ray Burster with a Super-Orbital Period

Abstract

MAXI J1621-501 is the first Swift/XRT Deep Galactic Plane Survey transient that was followed up with a multitude of space missions (NuSTAR, Swift, Chandra, NICER, INTEGRAL, and MAXI) and ground-based observatories (Gemini, IRSF, and ATCA). The source was discovered with MAXI on 2017 October 19 as a new, unidentified transient. Further observations with NuSTAR revealed 2 Type I X-ray bursts, identifying MAXI J1621-501 as a Low Mass X-ray Binary (LMXB) with a neutron star primary. Overall, 24 Type I bursts were detected from the source during a 15 month period. At energies below 10 keV, the source spectrum was best fit with three components: an absorbed blackbody with kT = 2.3 keV, a cutoff power law with index $\Gamma$ = 0.7, and an emission line centered on 6.3 keV. Timing analysis of the X-ray persistent emission and burst data has not revealed coherent pulsations from the source or an orbital period. We identified, however, a super-orbital period $\sim$78 days in the source X-ray light curve. This period agrees very well with the theoretically predicted radiative precession period of $\sim$82 days. Thus, MAXI J1621-501 joins a small group of sources characterized with super-orbital periods.

arXiv comment24 pages, Accepted for publication in The Astrophysical Journal (8/21/2019)

References in corpus (28)

• emcee: The MCMC Hammer
• On the Absorption of X-rays in the Interstellar Medium
• The Swift X-ray Telescope
• X-ray Properties of Black-Hole Binaries
• The Nuclear Spectroscopic Telescope Array (NuSTAR) Mission
• Atomic Data for Astrophysics. II. New Analytic Fits for Photoionization Cross Sections of Atoms and Ions
• Methods and results of an automatic analysis of a complete sample of Swift-XRT observations of GRBs
• Modelling the behaviour of accretion flows in X-ray binaries
• The MAXI Mission on the ISS: Science and Instruments for Monitoring All Sky X-Ray Images
• ISGRI: the INTEGRAL Soft Gamma-Ray Imager
• Improved Reflection Models of Black-Hole Accretion Disks: Treating the Angular Distribution of X-rays
• The INTEGRAL Science Data Centre (ISDC)
• The Australia Telescope Compact Array Broadband Backend (CABB)
• The Distance, Mass, and Radius of the Neutron Star in 4U 1608-52
• Stingray: A Modern Python Library For Spectral Timing
• Panchromatic study of GRB 060124: from precursor to afterglow
• Warped accretion discs and the long periods in X-ray binaries
• A Bayesian test for periodic signals in red noise
• Gas Slit Camera (GSC) onboard MAXI on ISS
• Evidence for a Photospheric Component in the Prompt Emission of the Short GRB120323A and its Effects on the GRB Hardness-Luminosity Relation
• No Time for Dead Time: Timing analysis of bright black hole binaries with NuSTAR
• Accurate early positions for Swift GRBS: enhancing X-ray positions with UVOT astrometry
• Solid-state Slit Camera (SSC) on Board MAXI
• No Time for Dead Time: Use the Fourier Amplitude Differences to Normalize Dead-time-affected Periodograms
• Search for Soft X-ray Flashes at Fireball Phase of Classical/Recurrent Novae using MAXI/GSC data
• NICER Detects a Soft X-ray Kilohertz Quasi-periodic Oscillation in 4U 0614+09
• In-flight PSF calibration of the NuSTAR hard X-ray optics
• A NICER look at the Aql X-1 hard state

Cited by in corpus (1)

• Low-Mass X-ray Binaries