Comparative Spectral Analysis of the Superluminous Supernova 2019neq

英文摘要：

We present a detailed spectroscopic analysis of the recently discovered fast evolving Type I superluminous supernova (SLSN-I), SN 2019neq (at redshift z = 0.1059) comparing it to the well-studied slow evolving SLSN-I, SN 2010kd (z = 0.101). Our investigation concentrates on optical spectra taken during the photospheric phase. The observations of SN 2019neq were carried out with the 10m Hobby-Eberly Telescope (HET) Low Resolution Spectrograph-2 (LRS2) at McDonald Observatory. We apply the SYN++ code to model the spectra taken at -4 days, +5 days and +29 days from maximum light. We examine the chemical evolution and ejecta composition of the SLSN by identifying the elements and ionization states in its spectra. Our analysis confirms that SN 2019neq is a fast evolving SLSN-I. We derive the number density of each ionization state at the epoch of the three observations. Finally, we give constraints on the lower limit of the ejecta mass and find a hint for a possible relation between the evolution timescale and the ejected mass of SLSNe-I.