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A Comprehensive X-ray Report on AT2019wey

Yao, Yuhan and Kulkarni, S. R. and Gendreau, K. C. and Jaisawal, Gaurava K. and Enoto, Teruaki and Grefenstette, Brian W. and Marshall, Herman L. and García, Javier A. and Ludlam, R. M. and Pike, Sean N. and Ng, Mason and Zhang, Liang and Altamirano, Diego and Jaodand, Amruta and Cenko, S. Bradley and Remillard, Ronald A. and Steiner, James F. and Negoro, Hitoshi and Brightman, Murray and Lien, Amy and Wolff, Michael T. and Ray, Paul S. and Mukai, Koji and Wadiasingh, Zorawar and Arzoumanian, Zaven and Kawai, Nobuyki and Mihara, Tatehiro and Strohmayer, Tod E. (2020) A Comprehensive X-ray Report on AT2019wey. . (Unpublished)

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The Galactic low-mass X-ray binary AT2019wey (ATLAS19bcxp, SRGA J043520.9+552226, SRGE J043523.3+552234, ZTF19acwrvzk) was discovered as a new optical transient in Dec 2019, and independently as an X-ray transient in Mar 2020. In this paper, we present comprehensive NICER, NuSTAR, Chandra, Swift, and MAXI observations of AT2019wey from ~1 year prior to the discovery to the end of September 2020. AT2019wey appeared as a ~1 mCrab source and stayed at this flux density for several months, displaying a hard X-ray spectrum that can be modeled as a power-law with photon index Gamma~1.8. In June 2020 it started to brighten, and reached ~20 mCrab in ~2 months. The inclination of this system can be constrained to i≾30 deg by modeling the reflection spectrum. Starting from late-August (~59082 MJD), AT2019wey entered into the hard-intermediate state (HIMS), and underwent a few week-long timescale outbursts, where the brightening in soft X-rays is correlated with the enhancement of a thermal component. Low-frequency quasi-periodic oscillation (QPO) was observed in the HIMS. We detect no pulsation and in timing analysis of the NICER and NuSTAR data. The X-ray states and power spectra of AT2019wey are discussed against the landscape of low-mass X-ray binaries.

Item Type:Report or Paper (Discussion Paper)
Related URLs:
URLURL TypeDescription Paper
Yao, Yuhan0000-0001-6747-8509
Kulkarni, S. R.0000-0001-5390-8563
Jaisawal, Gaurava K.0000-0002-6789-2723
Enoto, Teruaki0000-0003-1244-3100
Grefenstette, Brian W.0000-0002-1984-2932
García, Javier A.0000-0003-3828-2448
Ludlam, R. M.0000-0002-8961-939X
Pike, Sean N.0000-0002-8403-0041
Ng, Mason0000-0002-0940-6563
Zhang, Liang0000-0003-4498-9925
Altamirano, Diego0000-0002-3422-0074
Jaodand, Amruta0000-0002-3850-6651
Cenko, S. Bradley0000-0003-1673-970X
Remillard, Ronald A.0000-0003-4815-0481
Steiner, James F.0000-0002-5872-6061
Negoro, Hitoshi0000-0003-0939-1178
Brightman, Murray0000-0002-8147-2602
Lien, Amy0000-0002-7851-9756
Wolff, Michael T.0000-0002-4013-5650
Ray, Paul S.0000-0002-5297-5278
Wadiasingh, Zorawar0000-0002-9249-0515
Strohmayer, Tod E.0000-0001-7681-5845
Additional Information:YY thanks the Heising-Simons Foundation for support. RML acknowledges the support of NASA through Hubble Fellowship Program grant HST-HF2-51440.001. JAG acknowledges support from NASA grant 80NSSC17K0515 and from the Alexander von Humboldt Foundation. ZW acknowledges support from the NASA postdoctoral program. This work was partially supported under NASA contract No. NNG08FD60C and made use of data from the NuSTAR mission, a project led by the California Institute of Technology, managed by the Jet Propulsion Laboratory, and funded by the National Aeronautics and Space Administration. We thank the NuSTAR Operations, Software, and Calibration teams for support with the execution and analysis of these observations. This research has made use of the NuSTAR Data Analysis Software (nustardas), jointly developed by the ASI Science Data Center (ASDC, Italy) and the California Institute of Technology (USA). NICER research at NRL is supported by NASA.
Group:Astronomy Department, Space Radiation Laboratory, NuSTAR
Funding AgencyGrant Number
Heising-Simons Foundation2018-0908
NASA Hubble FellowshipHST-HF2-51440.001
Alexander von Humboldt FoundationUNSPECIFIED
NASA Postdoctoral ProgramUNSPECIFIED
NASA Einstein FellowshipUNSPECIFIED
Subject Keywords:X-rays: individual (AT2019wey); accretion, accretion disks; black hole physics
Record Number:CaltechAUTHORS:20210106-131324406
Persistent URL:
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:107349
Deposited By: George Porter
Deposited On:08 Jan 2021 22:00
Last Modified:08 Jan 2021 22:09

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