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

Journal Article · 04 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.  ^[9]; Prieto, J. L. ^[10]; Thompson, T. A. ^[3]; Coulter, D. A. ^[5]; Drout, M. R. ^[11]; Foley, R. J. ^[5]; Kilpatrick, C. D. ^[5] ; Piro, A. L. ^[2]; Rojas-Bravo, C. ^[5]; Buckley, D. A. H.  ^[12]; Gromadzki, M. ^[13]; Dimitriadis, G. ^[5]; Siebert, M. R. ^[5]; Do, A. ^[6]; Huber, M. E. ^[6]; Payne, A. V. ^[6]

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1. The Ohio State Univ., Columbus, OH (United States)
2. Carnegie Observatories, Pasadena, CA (United States)
3. The Ohio State Univ., Columbus, OH (United States). Center for Cosmology and Astro Particle Physics (CCAPP)
4. Univ. of Copenhagen (Denmark). The Niels Bohr Inst.; Univ. of California, Santa Cruz, CA (United States)
5. Univ. of California, Santa Cruz, CA (United States)
6. Univ. of Hawaii, Honolulu, HI (United States)
7. Peking Univ., Beijing (China)
8. Peking Univ., Beijing (China); Universidad Diego Portales, Santiago (Chile); Univ. of Virginia, Charlottesville, VA (United States)
9. The Ohio State Univ., Columbus, Ohio (United States). Dept. of Astronomy
10. Universidad Diego Portales, Santiago (Chile)
11. Univ. of Toronto, ON (Canada)
12. South African Astronomical Observatory, Cape Town (South Africa)
13. Univ. of Warsaw (Poland)

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 ~ 2.5 × 10⁴ 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 Office of Science (SC); USDOE
• Grant/Contract Number: SC0019323
• OSTI ID: 1615693
• Alternate ID(s): OSTI ID: 1803686
• Journal Information: Monthly Notices of the Royal Astronomical Society, Vol. 494, Issue 2; ISSN 0035-8711
• Publisher: Royal Astronomical SocietyCopyright Statement
• Country of Publication: United States
• Language: English