ASASSN-15lh: A highly super-luminous supernova

• Published in: Science (American Association for the Advancement of Science) Vol. 351; no. 6270; pp. 257 - 260
• Main Authors: Dong, Subo, Shappee, B. J., Prieto, J. L., Jha, S. W., Stanek, K. Z., Holoien, T. W.-S., Kochanek, C. S., Thompson, T. A., Morrell, N., Thompson, I. B., Basu, U., Beacom, J. F., Bersier, D., Brimacombe, J., Brown, J. S., Bufano, F., Chen, Ping, Conseil, E., Danilet, A. B., Falco, E., Grupe, D., Kiyota, S., Masi, G., Nicholls, B., E, F. Olivares, Pignata, G., Pojmanski, G., Simonian, G. V., Szczygiel, D. M., Woźniak, P. R.
• Format: Journal Article
• Language: English
• Published: Washington American Association for the Advancement of Science 15-01-2016; The American Association for the Advancement of Science; American Association for the Advancement of Science (AAAS)
• Subjects: ASTRONOMY AND ASTROPHYSICS; Luminosity; Star & galaxy formation; Supernovae
• ISSN: 0036-8075; 1095-9203
• DOI: 10.1126/science.aac9613

We report the discovery of ASASSN-15lh (SN 2015L), which we interpret as the most luminous supernova yet found. At redshift z = 0.2326, ASASSN-15lh reached an absolute magnitude of Mu,AB = −23.5 ± 0.1 and bolometric luminosity Lbol = (2.2 ± 0.2) × 10⁴⁵ ergs s⁻¹, which is more than twice as luminous as any previously known supernova. It has several major features characteristic of the hydrogen-poor super-luminous supernovae (SLSNe-l), whose energy sources and progenitors are currently poorly understood. In contrast to most previously known SLSNe-l that reside in star-forming dwarf galaxies, ASASSN-15lh appears to be hosted by a luminous galaxy (MK ≈ −25.5) with little star formation. In the 4 months since first detection, ASASSN-15lh radiated (1.1 ± 0.2) × 10⁵² ergs, challenging the magnetar model for its engine.