Abstract Details
| Name: Shubham Srivastav Affiliation: Indian Institute of Astrophysics Conference ID: ASI2016_807 Title : PSN J15053007+0138024 : a faint transitional type Ia supernova. Authors and Co-Authors : G. C. Anupama (IIA) D. K. Sahu (IIA) Abstract Type : Poster Abstract Category : Extragalactic astronomy Abstract : Optical observations of type Ia supernova (SN) PSN J15053007+0138024 obtained at the Himalayan Chandra Telescope, spanning a phase of $-5$ to $+140$ days since $B$-band maximum are presented. The SN reached $B$-band maximum on JD 2457113.3, at a peak apparent magnitude of $m_B = 13.99 \pm 0.02$. The SN showed a fast post-maximum decline in luminosity. The decline rate parameter in $B$-band was measured to be $\Delta m_{15}(B) = 1.71 \pm 0.04$. Adopting a distance modulus of $\sim 31.6$ mag for the host galaxy NGC 5839, the peak absolute $B$-band luminosity is $\sim -17.9 \pm 0.2$ after correcting for Milky Way reddening, making it fainter than what is expected from the width-luminosity relationship. Fitting an analytical model to the quasi-bolometric light curve of the SN indicated that a total of $\sim 0.70$ M$_{\odot}$ was ejected, whereas $\sim 0.20$ M$_{\odot}$ of $^{56}$Ni was synthesized in the explosion. The spectra indicated a rapid velocity evolution as measured from the Si~{\sc ii} $\lambda 6355$ feature, with a velocity gradient of $\sim 100$ km/sec/day between +0 and +10 days since $B$-band maximum. The rapid velocity evolution, along with the fast decline rate places this event in the FAINT subclass (Benetti et al. 2005), whereas the equivalent widths of Si~{\sc ii} features close to $B$-band maximum place the event in the Cool (CL) subclass (Branch et al. 2006) among Ia supernovae (SNe). Although the absolute luminosity of this event is closer to the sublumious 1991bg-like class of SNe Ia, other photometric and spectroscopic properties - like the secondary peak in the $I$-band light curve and the absence of Ti{\sc ii} features in the early spectra place it closer to normal SNe Ia. This event is thus classified as a transitional Ia, with properties intermediate to normal and subluminous SNe Ia. |