SN 2013ab: a normal Type IIP supernova in NGC 5669

Abstract

We present densely-sampled ultraviolet/optical photometric and low-resolution optical spectroscopic observations of the type IIP supernova 2013ab in the nearby (∼24 Mpc) galaxy NGC 5669, from 2 to 190d after explosion. Continuous photometric observations, with the cadence of typically a day to one week, were acquired with the 1-2m class telescopes in the LCOGT network, ARIES telescopes in India and various other telescopes around the globe. The light curve and spectra suggest that the SN is a normal type IIP event with a plateau duration of ∼ 80 days with mid plateau absolute visual magnitude of -16.7, although with a steeper decline during the plateau (0.92 mag 100 d −1 in V band) relative to other archetypal SNe of similar brightness. The velocity profile of SN 2013ab shows striking resemblance with those of SNe 1999em and 2012aw. Following the Rabinak & Waxman (2011) prescription, the initial temperature evolution of the SN emission allows us to estimate the progenitor radius to be ∼ 800 R ⊙ , indicating that the SN originated from a red supergiant star. The distance to the SN host galaxy is estimated to be 24.3 Mpc from expanding photosphere method (epm). From our observations, we estimate that 0.064 M ⊙ of 56 Ni was synthesized in the explosion. General relativistic, radiation hydrodynamical modeling of the SN infers an explosion energy of 0.35 × 10 51 erg, a progenitor mass (at the time of explosion) of ∼ 9 M ⊙ and an initial radius of ∼ 600 R ⊙ .

Photometric and polarimetric observations of fast declining Type II supernovae 2013hj and 2014G

“…The time of peak in early light curves (Tab. 2, Row:1) are consistent with most typical and common fast-rising SNe IIP like 2005cs (Pastorello et al 2009), 2004et (Sahu et al 2006) and 2013ab (Bose et al 2015a), which is significantly faster than slow-rising SNe, e.g. SNe 2006bp (Quimby et al 2007), 2009bw (Inserra et al 2012) and 2012aw (Bose et al 2013).…”

“…2 (Row:2). This is steeper than the values reported for generic type IIP SNe 1999em (Leonard et al 2002b), 1999em (Leonard et al 2002a), 2012aw (Bose et al 2013) and 2013ab (Bose et al 2015a), but flatter than the fast declining SNe like SN 2013by (Valenti et al 2015), SN 2013ej (Bose et al 2015b) and 2014G (this paper). For example, decline rates for SN 2012aw are 5.60, 1.74, 0.55 mag (100 d) −1 in U BV -bands and for SN 2013ab decline rates are 7.60, 2.72, 0.92, 0.59 and 0.30 mag (100 d) −1 in UBVRI bands, whereas SN 2013ej decline rates are 6.60, 3.57, 1.74, 1.07 and 0.74 mag (100 d) −1 .…”

“…Moreover, from visual comparison with other SNe II spectra (e.g., Valenti et al 2014;Bose et al 2015a) at early epochs, the December 13 spectrum looks no older than four days post explosion. Therefore, we adopt an explosion epoch (0d) of December 10.5 UTC, 2013 (JD = 2456637.0 ± 1.5 days) for SN 2013hj.…”

“…After the initial peak the light curves decline slowly until the plateau ends. SN 2013hj does not show very sharp transition in slope at the end of plateau as is seen in generic SNe IIP, e.g., SNe 1999em (Leonard et al 2002b), 1999gi (Leonard et al 2002a), 2004et (Sahu et al 2006, 2013ab (Bose et al 2015a). Rather the light curve shows linearity only up to ∼ 80d, thereafter it shows a gradual increase in slope until it reaches the end of plateau at around ∼ 96 − 100d.…”

EXTENSIVE SPECTROSCOPY AND PHOTOMETRY OF THE TYPE IIP SUPERNOVA 2013ej

“…Even the typical SNeIIP that exhibit flat plateaus, like SN2006bp (<73 day, Quimby et al 2007), SN2013ab (∼80 day, Bose et al 2015b), and SN2003hn (∼75 day, Bersten et al 2011), have shorter plateau duration compared to that of SN2013ej. This indicates that the envelope mass of SN2013ej is not atypical.…”