Related papers: ZTF SN Ia DR2: High-velocity components in the Si …

We present extensive spectroscopic observations for one of the closest type Ia supernovae (SNe Ia), SN 2014J discovered in M82, ranging from 10.4 days before to 473.2 days after B-band maximum light. The diffuse interstellar band (DIB)…

We present late-time spectra of eight Type Ia supernovae (SNe Ia) obtained at $>200$ days after peak brightness using the Gemini South and Keck telescopes. All of the SNe Ia in our sample were nearby, well separated from their host galaxy's…

The abundance distribution in the ejecta of the peculiar slowly declining Type Ia supernova (SN\,Ia) SN\,1999aa is obtained by modelling a time series of optical spectra. Similar to SN\,1991T, SN\,1999aa was characterised by early-time…

We present an investigation of the full width at half maximum (FWHM, or {\gamma}) of absorption features of Type Ia supernova (SNe Ia). We found that, the average value of FWHM can be well predicted with the rest wavelength ({\lambda}). The…

In the new era of time-domain surveys Type Ia supernovae are being caught sooner after explosion, which has exposed significant variation in their early light curves. Two driving factors for early time evolution are the distribution of…

Flux excesses in the early time light curves of Type Ia supernovae (SNe\,Ia) are predicted by multiple theoretical models and have been observed in a number of nearby SNe\,Ia over the last decade. However, the astrophysical processes that…

Using VLT-FORS1 we performed optical spectropolarimetric observations of the Type Ia SN2006X on 7 pre-maximum epochs (day -10 to day -1) and one post-maximum epoch (+39 days). The SN shows strong continuum interstellar polarization reaching…

An open question in SN Ia research is where the boundary lies between 'normal' Type Ia supernovae (SNe Ia) that are used in cosmological measurements and those that sit off the Phillips relation. We present the spectroscopic modelling of…

Large photometric surveys with the aim of identifying many Type Ia supernovae (SNe) at moderate redshift are challenged in separating these SNe from other SN types. We are motivated to identify Type Ia SNe based only on broadband…

The spectrum of the normal Type Ia SN 1990N observed very early on (14 days before B maximum) was analysed by Fisher et al (1997), who showed that the large width and the unusual profile of the strong line near 6000\AA can be reproduced if…

Type Ia Supernovae have yet again the opportunity to revolutionize the field of cosmology as the new generation of surveys are acquiring thousands of nearby SNeIa opening a new era in cosmology: the direct measurement of the growth of…

The remarkable uniformity of Type Ia supernovae (SNe Ia) has allowed astronomers to use them as distance indicators to measure the properties and expansion history of the Universe. However, SNe Ia exhibit intrinsic variation in both their…

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…

Low-luminosity type II supernovae (LL SNe~II) make up the low explosion energy end of core-collapse SNe, but their study and physical understanding remain limited. We present SN\,2016aqf, a LL SN~II with extensive spectral and photometric…

We present extensive, well-sampled optical and ultraviolet photometry and optical spectra of the Type Ia supernova (SN Ia) 2017hpa. The light curves indicate that SN 2017hpa is a normal SN Ia with an absolute peak magnitude of $M_{\rm…

We present the volumetric rates and luminosity functions (LFs) of Type Ia supernovae (SNe Ia) from the $V$-band All-Sky Automated Survey for Supernovae (ASAS-SN) catalogues spanning discovery dates from UTC 2014-01-26 to UTC 2017-12-29. Our…

A non-local-thermodynamic-equilibrium (NLTE) level population model of the first and second ionisation stages of iron, nickel and cobalt is used to fit a sample of XShooter optical + near-infrared (NIR) spectra of Type Ia supernovae (SNe…

We describe our ongoing program designed to measure the SN-Ia rate in a sample of massive z=0.5-0.9 galaxy clusters. The SN-Ia rate is a poorly known observable, especially at high z, and in cluster environments. The SN rate and its…

We study the pseudo equivalent width of the Si II 4000 feature of Type Ia supernovae in the redshift range 0.0024 < z < 0.634. We find that this spectral indicator correlates with the lightcurve color excess (SALT2 c) as well as previously…

The early lightcurves of Type Ia supernovae (SNe Ia) can be used to test predictions about their progenitor systems. If the progenitor system consists of a single white dwarf in a binary with a Roche-lobe-overflowing non-degenerate stellar…