Details

Autor(en) / Beteiligte

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

Titel

A Comprehensive X-Ray Report on AT2019wey

Ist Teil von

• The Astrophysical journal, 2021-10, Vol.920 (2), p.121

Ort / Verlag

Goddard Space Flight Center: The American Astronomical Society

Erscheinungsjahr

2021

Quelle

EZB Free E-Journals

Beschreibungen/Notizen

• The Galactic low-mass X-ray binary AT2019wey (ATLAS19bcxp, SRGAJ043520.9+552226, SRGEJ043523.3+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 Γ ~ 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° by modelling 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.