Related papers: Investigating the Unusual Spectroscopic Time-Evolu…

We present 65 optical spectra of the Type Ia supernova SN 2012fr, of which 33 were obtained before maximum light. At early times SN 2012fr shows clear evidence of a high-velocity feature (HVF) in the Si II 6355 line which can be cleanly…

We analyse spectroscopic measurements of 122 type Ia supernovae (SNe Ia) with z<0.09 discovered by the Palomar Transient Factory, focusing on the properties of the Si II 6355 and Ca II `near-infrared triplet' absorptions. We examine the…

We present photometry and time-series spectroscopy of the nearby type Ia supernova (SN Ia) SN 2015F over $-16$ days to $+80$ days relative to maximum light, obtained as part of the Public ESO Spectroscopic Survey of Transient Objects…

The ZTF SN Ia Data Release 2 provides a perfect opportunity to perform a thorough search for, and subsequent analysis of, high-velocity components in the Si II $\lambda$6355 feature in the pre-peak regime. The source of such features…

We report measurements and analysis of high-velocity (> 20,000 km/s) and photospheric absorption features in a series of spectra of the Type Ia supernova (SN) 2009ig obtained between -14d and +13d with respect to the time of maximum B-band…

We present the optical photometric and spectroscopic observations of the nearby Type Ia supernova (SN) 2021hpr. The observations covered the phase of $-$14.37 to +63.68 days relative to its maximum luminosity in the $B$ band. The evolution…

We present the optical (UBVRI) and ultraviolet (Swift-UVOT) photometry, and optical spectroscopy of Type Ia supernova SN 2017hpa. We study broadband UV+optical light curves and low resolution spectroscopy spanning from $-13.8$ to $+108$~d…

Spectropolarimetry provides the means to probe the 3D geometries of Supernovae at early times. We report spectropolarimetric observations of the Type Ia Supernova 2012fr at four epochs: -11, -5, +2 and +24 days, with respect to B-lightcurve…

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…

Extensive optical and ultraviolet (UV) observations of the type Ia supernova (SN Ia) 2012fr are presented in this paper. It has a relatively high luminosity, with an absolute $B$-band peak magnitude of about $-19.5$ mag and a smaller…

We present detailed ultraviolet, optical and near-infrared light curves of the Type Ia supernova (SN) 2012fr, which exploded in the Fornax cluster member NGC 1365. These precise high-cadence light curves provide a dense coverage of the flux…

We present extensive photometry at ultraviolet (UV), optical, and near-infrared (NIR) wavelengths, as well as dense sampling of optical spectra, for the normal type Ia supernova (SN Ia) 2005cf. From the well-sampled light curves, we find…

In spite of the apparent lack of Si II and S II features in its spectra, SN 2002cx was classified as a peculiar Type Ia supernova (SN Ia) on the basis of its overall photometric and spectroscopic behavior. Spectra obtained near maximum…

The Type Ia SN 2000cx exhibited multiple peculiarities, including a lopsided B-band light-curve peak that does not conform to current methods for using shapes of light curves to standardize SN Ia luminosities. We use the parameterized…

We present Keck spectropolarimetry of the unusual type Ia supernova (SN Ia) 2005hk several days before maximum light. An analysis of the high signal-to-noise-ratio total-flux spectrum shows the object's extreme similarity to the peculiar SN…

We use a sample of 58 low-redshift (z <= 0.03) Type Ia supernovae (SNe Ia) having well-sampled light curves and spectra near maximum light to examine the behaviour of high-velocity features (HVFs) in SN Ia spectra. We take advantage of the…

The absorption feature O I 7773 is an important spectral indicator for type Ia supernovae (SNe~Ia) that can be used to trace the unburned material at outer layers of the exploding white dwarf. In this work, we use a large sample of SNe~Ia…

We present observations of SN 2022joj, a peculiar Type Ia supernova (SN Ia) discovered by the Zwicky Transient Facility (ZTF). SN 2022joj exhibits an unusually red $g_\mathrm{ZTF}-r_\mathrm{ZTF}$ color at early times and a rapid blueward…

The spectral evolution of the peculiar SN Ic 2002ap during the first 40 days is presented. The spectra display very broad absorption features, which are typical of "hypernovae". The maximum expansion velocity measured on the earliest…

In this paper, we present photometric and spectroscopic observations of a subluminous type Ia supernova (SN Ia) 2012ij, which has an absolute $B$-band peak magnitude $M_{B,\rm{max}}$ = $-$17.95 $\pm$ 0.15 mag. The $B$-band light curve…