Thumbnail
Access Restriction
Open

Author Roy, R. ♦ Kumar, Brijesh ♦ Chandola, H. C. ♦ Sagar, Ram
Source Aryabhatta Research Institute of Observational Sciences (ARIES)
Content type Text
File Format PDF
Language English
Subject Domain (in DDC) Natural sciences & mathematics ♦ Physics
Subject Keyword Supernovae: general ♦ Supernovae: individual ♦ SN 2008gz – galaxies ♦ Distances and redshifts – galaxies ♦ Individual: NGC 3672.
Abstract We present BVRI photometric and low-resolution spectroscopic investigation of the Type IIcore-collapse supernova (SN) 2008gz, which occurred in a star-forming arm and within a halflightradius (solar metallicity region) of the nearby spiral galaxy NGC 3672. The SN event wasdetected late, and a detailed investigation of its light curves and spectra spanning 200 d suggestthat it is an event of Type IIP similar to the archetypal SNe 2004et and 1999em. However,in contrast to other events of its class, SN 2008gz exhibits a rarely observed V magnitudedrop of 1.5 over the period of a month during the plateau to nebular phase. Using an AV of0.21 mag as a lower limit and a distance of 25.5 Mpc, we estimate a synthesized ⁵⁶Ni massof 0.05 ± 0.01Mʘ, a mid-plateau MV of −16.6 ± 0.2mag and a total radiant energy of∼10⁴⁹ erg. The photospheric velocity is observed to be higher than observed for SN 2004etat similar epochs, indicating that the explosion energy was comparable to or higher than thatof SN 2004et. A similar trend was also seen for the expansion velocity of H envelopes. Bycomparing the properties of SN 2008gz with other well-studied events, as well as by usinga recent simulation of pre-SN models by Dessart, Livne & Waldman, we infer an explosionenergy range of 2–3 × 10⁵¹ erg, and this coupled with the observed width of the forbidden[O I] 6300–6364Å line at 275 d after the explosion gives an upper limit for the main-sequence(non-rotating, solar metallicity) progenitor mass of 17Mʘ. Our narrow-band Hα observation,taken nearly 560 d after the explosion, and the presence of an emission kink at zero velocityin the Doppler-corrected spectra of SN indicate that the event took place in a low-luminositystar-forming HII region.
Part of series mn414-167
Educational Use Research
Education Level UG and PG
Learning Resource Type Article