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تسجيل مستخدم جديدASASSN-14dq: A fast-declining type II-P Supernova in a low-luminosity host galaxy
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Optical broadband (UBVRI) photometric and low-resolution spectroscopic observations of the type II-P supernova (SN) ASASSN-14dq are presented. ASASSN-14dq exploded in a low-luminosity/metallicity host galaxy UGC 11860, the signatures of which are present as weak iron lines in the photospheric phase spectra. The SN has a plateau duration of $sim,$90 d, with a plateau decline rate of 1.38 $rm mag (100 d)^{-1}$ in V-band which is higher than most type II-P SNe. ASASSN-14dq is a luminous type II-P SN with a peak $V$-band absolute magnitude of -17.7$,pm,$0.2 mag. The light curve of ASASSN-14dq indicates it to be a fast-declining type II-P SN, making it a transitional event between the type II-P and II-L SNe. The empirical relation between the steepness parameter and $rm ^{56}Ni$ mass for type II SNe was rebuilt with the help of well-sampled light curves from the literature. A $rm ^{56}Ni$ mass of $sim,$0.029 M$_{odot}$ was estimated for ASASSN-14dq, which is slightly lower than the expected $rm ^{56}Ni$ mass for a luminous type II-P SN. Using analytical light curve modelling, a progenitor radius of $rm sim3.6times10^{13}$ cm, an ejecta mass of $rm sim10 M_{odot}$ and a total energy of $rm sim,1.8times 10^{51}$ ergs was estimated for this event. The photospheric velocity evolution of ASASSN-14dq resembles a type II-P SN, but the Balmer features (H$alpha$ and H$beta$) show relatively slow velocity evolution. The high-velocity H$alpha$ feature in the plateau phase, the asymmetric H$alpha$ emission line profile in the nebular phase and the inferred outburst parameters indicate an interaction of the SN ejecta with the circumstellar material (CSM).
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