Related papers: Oxygen and helium in stripped-envelope supernovae

We present optical, near-infrared, and radio observations of supernova (SN) SN~IIb 2022crv. We show that it retained a very thin H envelope and transitioned from a SN~IIb to a SN~Ib; prominent H$\alpha$ seen in the pre-maximum phase…

The absence of helium features in optical spectra is one of the classification criteria for Type Ic supernovae (SNe Ic). However, it is highly debated whether helium is truly absent in ejecta or spectroscopically undetectable in the optical…

We present a simple and well defined prescription to compare absorption lines in supernova (SN) spectra with lists of transitions drawn from the National Institute of Standards and Technology (NIST) database. The method is designed to be…

Due to high-cadence automated surveys, we can now detect and classify supernovae (SNe) within a few days after explosion, if not earlier. Early-time spectra of young SNe directly probe the outermost layers of the ejecta, providing insights…

We study a sample of 16 Type Ia supernovae (SNe Ia) having both spectroscopic and photometric observations within 2 $-$ 3 days after the first light. The early $B-V$ colors of such a sample tends to show a continuous distribution. For…

We re-examine the classifications of supernovae (SNe) presented in the Lick Observatory Supernova Search (LOSS) volume-limited sample with a focus on the stripped-envelope SNe. The LOSS volume-limited sample, presented by Leaman et al.…

Type IIP supernovae (SNe IIP) have recently been proposed as metallicity ($Z$) probes. The spectral models of Dessart et al. (2014) showed that the pseudo-equivalent width of Fe II $\lambda$5018 (pEW$_{5018}$) during the plateau phase…

We present detailed non-local thermodynamic equilibrium (NLTE) synthetic spectra for comparison with a time series of observed optical spectra of the Type Ic supernova 1994I which occurred in M51. With the exceptions of Si I and S I, we…

The optical observations of Ic-4 supernova (SN) 2016coi/ASASSN-16fp, from $\sim 2$ to $\sim450$ days after explosion, are presented along with analysis of its physical properties. The SN shows the broad lines associated with SNe Ic-3/4 but…

Helium is expected to be present in the ejecta of some hydrogen-poor superluminous supernovae (SLSN-I). However, so far only one event, PTF10hgi has been identified with He features in its photospheric spectra (Quimby et al. 2018). We…

Ultra-stripped and Type Ibn supernovae (USSNe and SNe Ibn, respectively) are fast-evolving, hydrogen-poor transients that often show signs of interaction with dense circumstellar material (CSM). Wu & Fuller (2022) identify a mass range for…

While O is often seen in spectra of Type Ia supernovae (SNe Ia) as both unburned fuel and a product of C burning, C is only occasionally seen at the earliest times, and it represents the most direct way of investigating primordial white…

Type Ibn supernovae (SNe) are a mysterious class of transients whose spectra exhibit persistently narrow HeI lines, and whose bolometric light curves are typically fast evolving and overluminous at peak relative to standard Type Ibc SNe. We…

We present optical observations of supernova (SN) 2014ek discovered during the Tsinghua-NAOC Transient Survey (TNTS), which shows properties that are consistent with those of SN 2002cx-like events (dubbed as SNe Iax). The photometry…

We present a sample of Type Icn supernovae (SNe Icn), a newly-discovered class of transients characterized by their interaction with H- and He-poor circumstellar material (CSM). This sample is the largest collection of SNe Icn to date and…

We present the results of modelling archival observations of type Ib SN 1999dn. In the spectra, two He I absorption features are seen: a slower component with larger opacity, and a more rapid He I component with smaller opacity.…

The velocity of the inner ejecta of stripped-envelope core-collapse supernovae (CC-SNe) is studied by means of an analysis of their nebular spectra. Stripped-envelope CC-SNe are the result of the explosion of bare cores of massive stars…

Supernovae (SNe) with photospheric spectra devoid of Hydrogen and Helium features are generally classified as Type Ic SNe (SNe Ic). However, there is ongoing debate as to whether Helium can be hidden in the ejecta of SNe Ic (that is, Helium…

Hydrogen/Helium-poor stripped-envelope core-collapse supernovae with broad lines (SNe Ic-bl) almost always accompany the nearby ($z < 0.3$) jetted relativistic explosions known as long duration gamma-ray bursts (GRBs). However, the majority…

We present the first unambiguous detection of helium emission lines in spectra of Type Ic supernovae (SNe Ic). The presence of He I lines, with full width at half maximum ~ 2000 km/s, and the distinct absence of any other intermediate-width…