To TDE or not to TDE: the luminous transient ASASSN-18jd with TDE-like and AGN-like qualities

Journal Article · 03 April 2020 · Monthly Notices of the Royal Astronomical Society

DOI: https://doi.org/10.1093/mnras/staa859 · OSTI ID:1615693

Neustadt, J. M. M.  ^[1]; Holoien, T. W-S  ^[2]; Kochanek, C. S. ^[3]; Auchettl, K. ^[4]; Brown, J. S. ^[5]; Shappee, B. J. ^[6]; Pogge, R. W. ^[1]; Dong, Subo ^[7]; Stanek, K. Z. ^[1]; Tucker, M. A. ^[6]; Bose, S.  ^[3]; Chen, Ping ^[7]; Ricci, C. ^[8]; Vallely, P. J.  ^[1]; Prieto, J. L. ^[9]; Thompson, T. A. ^[3]; Coulter, D. A. ^[5]; Drout, M. R. ^[10]; Foley, R. J. ^[5]; Kilpatrick, C. D. ^[5] ; Piro, A. L. ^[2]; Rojas-Bravo, C. ^[5]; Buckley, D. A. H.  ^[11]; Gromadzki, M. ^[12]; Dimitriadis, G. ^[5]; Siebert, M. R. ^[5]; Do, A. ^[6]; Huber, M. E. ^[6]; Payne, A. V. ^[6]

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1. Department of Astronomy, The Ohio State University, 140 West 18th Avenue, Columbus, OH 43210, USA
2. The Observatories of the Carnegie Institution for Science, 813 Santa Barbara Street, Pasadena, CA 91101, USA
3. Department of Astronomy, The Ohio State University, 140 West 18th Avenue, Columbus, OH 43210, USA, Center for Cosmology and AstroParticle Physics (CCAPP), The Ohio State University, 191 W. Woodruff Avenue, Columbus, OH 43210, USA
4. DARK, Niels Bohr Institute, University of Copenhagen, Lyngbyvej 2, DK-2100 Copenhagen, Denmark, Department of Astronomy and Astrophysics, University of California, Santa Cruz, CA 95064, USA
5. Department of Astronomy and Astrophysics, University of California, Santa Cruz, CA 95064, USA
6. Institute for Astronomy, University of Hawai’i, 2680 Woodlawn Drive, Honolulu, HI 96822, USA
7. Kavli Institute for Astronomy and Astrophysics, Peking University, Yi He Huan Road 5, Hai Dian District, Beijing 100871, China
8. Kavli Institute for Astronomy and Astrophysics, Peking University, Yi He Huan Road 5, Hai Dian District, Beijing 100871, China, Núcleo de Astronomía de la Facultad de Ingeniería y Ciencias, Universidad Diego Portales, Av. Ejército 441, Santiago, Chile, Department of Physics and Astronomy, George Mason University, MS 3F3, 4400 University Drive, Fairfax, VA 22030, USA
9. Núcleo de Astronomía de la Facultad de Ingeniería y Ciencias, Universidad Diego Portales, Av. Ejército 441, Santiago, Chile, Millennium Institute of Astrophysics, Santiago, Chile
10. Department of Astronomy and Astrophysics, University of Toronto, 50 St George St, Toronto, ON M5S 3H4, Canada
11. South African Astronomical Observatory, PO Box 9, Observatory 7935, Cape Town, South Africa
12. Astronomical Observatory, University of Warsaw, Al. Ujazdowskie 4, PL-00-478 Warszawa, Poland

ABSTRACT We present the discovery of ASASSN-18jd (AT 2018bcb), a luminous optical/ultraviolet(UV)/X-ray transient located in the nucleus of the galaxy 2MASX J22434289–1659083 at z = 0.1192. Over the year after discovery, Swift UltraViolet and Optical Telescope (UVOT) photometry shows the UV spectral energy distribution of the transient to be well modelled by a slowly shrinking blackbody with temperature $$T \sim 2.5 \times 10^{4} \, {\rm K}$$, a maximum observed luminosity of $$L_{\rm max} = 4.5^{+0.6}_{-0.3}\times 10^{44} \, {\rm erg \,s}^{-1}$$, and a radiated energy of $$E = 9.6^{+1.1}_{-0.6} \times 10^{51} \, {\rm erg}$$. X-ray data from Swift X-Ray Telescope (XRT) and XMM–Newton show a transient, variable X-ray flux with blackbody and power-law components that fade by nearly an order of magnitude over the following year. Optical spectra show strong, roughly constant broad Balmer emission and transient features attributable to He ii, N iii–v, O iii, and coronal Fe. While ASASSN-18jd shares similarities with tidal disruption events (TDEs), it is also similar to the newly discovered nuclear transients seen in quiescent galaxies and faint active galactic nuclei (AGNs).

• Research Organization: Krell Institute, Ames, IA (United States)
• Sponsoring Organization: USDOE; USDOE Office of Science (SC)
• Grant/Contract Number: SC0019323
• OSTI ID: 1615693
• Journal Information: Monthly Notices of the Royal Astronomical Society, Journal Name: Monthly Notices of the Royal Astronomical Society Journal Issue: 2 Vol. 494; ISSN 0035-8711
• Publisher: Oxford University PressCopyright Statement
• Country of Publication: United Kingdom
• Language: English