ASASSN-18ey: The Rise of a New Black-Hole X-ray Binary

Autor: John L. Tonry, John F. Beacom, L. Denneau, Michael A. Tucker, A. N. Heinze, Kristen C. Dage, Subo Dong, H. Weiland, A. Rest, Thomas W.-S. Holoien, B. Stalder, Laura Chomiuk, Arash Bahramian, Todd A. Thompson, J. V. Shields, J. L. Prieto, K. W. Smith, Benjamin J. Shappee, Asas-Sn, H. Flewelling, Katie Auchettl, Christopher S. Kochanek, Krzysztof Z. Stanek, Jay Strader, D. M. Rowan, M. E. Huber
Jazyk: angličtina
Rok vydání: 2018
Předmět:
Popis: We present the discovery of ASASSN-18ey (MAXI J1820+070), a new black hole low-mass X-ray binary discovered by the All-Sky Automated Survey for SuperNovae (ASAS-SN). A week after ASAS-SN discovered ASASSN-18ey as an optical transient, it was detected as an X-ray transient by MAXI/GCS. Here, we analyze ASAS-SN and Asteroid Terrestrial-impact Last Alert System (ATLAS) pre-outburst optical light curves, finding evidence of intrinsic variability for several years prior to the outburst. While there was no long-term rise leading to outburst, as has been seen in several other systems, the start of the outburst in the optical preceded that in the X-rays by $7.20\pm0.97~\rm days$. We analyze the spectroscopic evolution of ASASSN-18ey from pre-maximum to $> 100~\rm days$ post-maximum. The spectra of ASASSN-18ey exhibit broad, asymmetric, double-peaked H$\alpha$ emission. The Bowen blend ($\lambda \approx 4650$\AA) in the post-maximum spectra shows highly variable double-peaked profiles, likely arising from irradiation of the companion by the accretion disk, typical of low-mass X-ray binaries. The optical and X-ray luminosities of ASASSN-18ey are consistent with black hole low-mass X-ray binaries, both in outburst and quiescence.
Comment: 10 pages, 5 figures, accepted by ApJL. A summary video describing this publication can be found at https://youtu.be/YbM_koBfRSI
Databáze: OpenAIRE