Massive stars exploding in a He-rich circumstellar medium – VII. The metamorphosis of ASASSN-15ed from a narrow line Type Ibn to a normal Type Ib Supernova. Issue 4 (9th September 2015)

• Record Type: Journal Article
• Authors: Pastorello, A.; Prieto, J. L.; Elias-Rosa, N.; Bersier, D.; Hosseinzadeh, G.; Morales-Garoffolo, A.; Noebauer, U. M.; Taubenberger, S.; Tomasella, L.; Kochanek, C. S.; Falco, E.; Basu, U.; Beacom, J. F.; Benetti, S.; Brimacombe, J.; Cappellaro, E.; Danilet, A. B.; Dong, Subo; Fernandez, J. M.; Goss, N.; Granata, V.; Harutyunyan, A.; Holoien, T. W.-S.; Ishida, E. E. O.; Kiyota, S.; Krannich, G.; Nicholls, B.; Ochner, P.; Pojmański, G.; Shappee, B. J.; Simonian, G. V.; Stanek, K. Z.; Starrfield, S.; Szczygieł, D.; Tartaglia, L.; Terreran, G.; Thompson, T. A.; Turatto, M.; Wagner, R. M.; Wiethoff, W. S.; Wilber, A.; Woźniak, P. R.;
• Is Part Of: Monthly notices of the Royal Astronomical Society. Volume 453:Issue 4(2015)
• Page Start: 3649
• Page End: 3661
• Publication Date: 2015-09-09
• Subjects: supernovae: general -- supernovae: individual: ASASSN-15ed -- supernovae: individual: SN 1991D -- supernovae: individual: SN 2006jc -- supernovae: individual: SN 2010al; Astronomy -- Periodicals; Periodicals; 520.5
• DOI: 10.1093/mnras/stv1812
• Languages: English
• ISSNs: 0035-8711

Abstract

Abstract: We present the results of the spectroscopic and photometric monitoring campaign of ASASSN-15ed. The transient was discovered quite young by the All Sky Automated Survey for SuperNovae (ASAS-SN) survey. Amateur astronomers allowed us to sample the photometric SN evolution around maximum light, which we estimate to have occurred on JD = 2457087.4 ± 0.6 in the r band. Its apparent r -band magnitude at maximum was r = 16.91 ± 0.10, providing an absolute magnitude M r ≈ −20.04 ± 0.20, which is slightly more luminous than the typical magnitudes estimated for Type Ibn SNe. The post-peak evolution was well monitored, and the decline rate (being in most bands around 0.1 mag d −1 during the first 25 d after maximum) is marginally slower than the average decline rates of SNe Ibn during the same time interval. The object was initially classified as a Type Ibn SN because early-time spectra were characterized by a blue continuum with superimposed narrow P-Cygni lines of He i, suggesting the presence of a slowly moving (1200–1500 km s −1 ), He-rich circumstellar medium. Later on, broad P-Cygni He i lines became prominent. The inferred velocities, as measured from the minimum of the broad absorption components, were between 6000 and 7000 km s −1 . As we attribute these broad features to the SN ejecta, this is the first time we have observed the transition of a Type Ibn SN to a Type Ib SN.