Related papers: SN2019dge: a Helium-rich Ultra-Stripped Envelope S…

We present $\textit{Hubble Space Telescope}$ imaging of the Calcium-rich supernova (SN) 2019ehk at 276 - 389 days after explosion. These observations represent the latest photometric measurements of a Calcium-rich transient to date and…

The nature of an emerging class of rapidly fading supernovae (RFSNe)--characterized by their short-lived light curve duration, but varying widely in peak brightness--remains puzzling. Whether the RFSNe arise from low-mass thermonuclear…

Stripped-envelope supernovae (SESNe) represent a significant fraction of core-collapse supernovae, arising from massive stars that have shed their hydrogen and, in some cases, helium envelopes. The origins and explosion mechanisms of SESNe…

SN2017egm is the closest (z=0.03) H-poor superluminous supernova (SLSN-I) detected to date, and a rare example of an SLSN-I in a massive and metal-rich galaxy. Here we present the HST UV & optical spectra covering (1000 - 5500)A taken at +3…

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…

Narrow transient emission lines (flash-ionization features) in early supernova (SN) spectra trace the presence of circumstellar material (CSM) around the massive progenitor stars of core-collapse SNe. The lines disappear within days after…

We present extensive ground-based and $Hubble~Space~Telescope$ ($HST$) photometry of the highly reddened, very nearby type Ia supernova (SN Ia) 2014J in M82, covering the phases from 9 days before to about 900 days after the $B$-band…

We present optical photometry and spectroscopy of SN 2019hnl. Discovered within ~26 hr of explosion by the ATLAS survey, SN 2019hnl is a typical Type IIP supernova with a peak absolute V band magnitude of -16.7+-0.1 mag, a plateau length of…

We present multi-wavelength observations and a comprehensive analysis of the nearby (D$\sim$14 Mpc) Type IIb supernova (SN IIb) 2024iss. Observations of SN2024iss include an early ZTF detection at $\sim$40 minutes after first light and the…

We present observations and modeling of SN 2016hnk, a Ca-rich supernova (SN) that is consistent with being the result of a He-shell double-detonation explosion of a C/O white dwarf. We find that SN 2016hnk is intrinsically red relative to…

Type II supernovae (SNe) stem from the core collapse of massive ($>8\ M_{\odot}$) stars. Owing to their short lifespan, we expect a very low rate of such events in elliptical host galaxies, where the star-formation rate is low, and which…

iPTF13ehe is a hydrogen-poor superluminous supernova (SLSN) at z=0.3434, with a slow-evolving light curve and spectral features similar to SN2007bi. It rises within (83-148)days (rest-frame) to reach a peak bolometric luminosity of…

Type Ibn supernovae (SNe) are a small yet intriguing class of explosions whose spectra are characterized by low-velocity helium emission lines with little to no evidence for hydrogen. The prevailing theory has been that these are the…

We present detailed observations of ZTF18abukavn (SN2018gep), discovered in high-cadence data from the Zwicky Transient Facility as a rapidly rising ($1.4\pm0.1$ mag/hr) and luminous ($M_{g,\mathrm{peak}}=-20$ mag) transient. It is…

We report Nearby Supernova Factory observations of SN 2005gj, the second confirmed case of a "hybrid" Type Ia/IIn supernova. Our early-phase photometry of SN 2005gj shows that the interaction is much stronger than for the prototype, SN…

We present observations of SN~2023xgo, a transitional Type Ibn/Icn supernova, from $-5.6$ to $+63$~days relative to the $r$-band peak. Early spectra show C~III $\lambda 5696$ emission reminiscent of Type~Icn SNe, which later gives way to…

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…

We present densely-sampled UBVRI/griz photometric and low-resolution (6-10A) optical spectroscopic observations from 4 to 270 days after explosion of a newly discovered type II SN 2012aw in a nearby (~9.9 Mpc) galaxy M95. The light-curve…

We present time-resolved optical spectroscopy of the dwarf nova CSS100603:112253-111037. Its optical spectrum is rich in helium, with broad, double-peaked emission lines produced in an accretion disc. We measure a line flux ratio…

Hydrodynamical simulations predict that a large amount of hydrogen (>0.1 solar masses) is removed from a hydrogen-rich companion star by the SN explosion in the single-degenerate scenario of Type Ia supernovae (SNe Ia). However,…