相关论文: Comparative Analysis of Peculiar Type Ia 1991bg-li…

A comparative study of optical spectra of Type Ia supernovae (SNe Ia) is extended, in the light of new data. The discussion is framed in terms of the four groups defined in previous papers of this series: core normal (CN); broad line (BL);…

A comparative study of near-maximum-light optical spectra of 24 Type Ia supernovae (SNe Ia) is presented. The spectra are quantified in two ways, and assigned to four groups. Seven "core-normal" SNe Ia have very similar spectra, except for…

A comparative study of spectra of 21 Type Ia supernovae (SNe Ia) obtained about one week before maximum light, and 8 spectra obtained 11 or more days before maximum, is presented. To a large extent the premaximum spectra exhibit the…

Attempts to reveal the spectroscopic diversity of Type Ia supernovae (SNe Ia) have led to subclassification schemes such as the Branch system, which classifies SNe Ia into four categories: core normal (CN), broad line (BL), cool (CL), and…

1991T-like supernovae are the luminous, slow-declining extreme of the Branch shallow-silicon (SS) subclass of Type Ia supernovae. They are distinguished by extremely weak Ca II H & K and Si II $\lambda6355$ and strong Fe III absorption…

A comparative study of optical spectra of Type Ia supernovae (SNe Ia) obtained near 1 week, 3 weeks, and 3 months after maximum light is presented. Most members of the four groups that were defined on the basis of maximum light spectra in…

Type Ia supernovae (SNe Ia) are important cosmological probes and contributors to galactic nucleosynthesis, particularly of the iron group elements. To improve both their reliability as cosmological probes and to understand galactic…

The properties of underluminous type Ia supernovae (SNe Ia) of the 91bg subclass have yet to be theoretically understood. Here, we take a closer look at the structure of the dim SN Ia 2005bl. We infer the abundance and density profiles…

Fast-declining Type Ia supernovae (SN Ia) separate into two categories based on their bolometric and near-infrared (NIR) properties. The peak bolometric luminosity ($\mathrm{L_{max}}$), the phase of the first maximum relative to the…

Type Ia supernovae are generally agreed to arise from thermonuclear explosions of carbon-oxygen white dwarfs. The actual path to explosion, however, remains elusive, with numerous plausible parent systems and explosion mechanisms suggested.…

Understanding the nature of the luminous 1991T-like supernovae is of great importance to supernova cosmology as they are likely to have been more common in the early universe. In this paper we explore the observational properties of…

In this letter a late-phase spectrum of SN 2010lp, a subluminous Type Ia supernova (SN Ia), is presented and analysed. As in 1991bg-like SNe Ia at comparable epochs, the spectrum is characterised by relatively broad [FeII] and [CaII]…

Optical observations of the Type Ia supernova (SN Ia) 2005bl in NGC 4070, obtained from -6 to +66 d with respect to the B-band maximum, are presented. The photometric evolution is characterised by rapidly-declining light curves and red…

We present a new photometric identification technique for SN 1991bg-like type Ia supernovae (SNe Ia), i.e. objects with light-curve characteristics such as later primary maxima and absence of secondary peak in redder filters. This method is…

We present a set of new quantitative classification criteria for major subclasses of Type I Supernovae (SNe). We analyze peak spectra of 146 SNe Ia from the Berkeley Supernova Ia Program (BSNIP), 12 SNe Ib, 19 SNe Ic (including 5 SNe Ic-BL)…

We present spectra of twelve Type Ia supernovae obtained in 1999 at the William Herschel Telescope and the Nordic Optical Telescope during a search for Type Ia supernovae (SN Ia) at intermediate redshift. The spectra range from z=0.178 to…

We present 2603 spectra of 462 nearby Type Ia supernovae (SN Ia) obtained during 1993-2008 through the Center for Astrophysics Supernova Program. Most of the spectra were obtained with the FAST spectrograph at the FLWO 1.5m telescope and…

Aims: Spectroscopic observations of Type Ia supernovae obtained at the New Technology Telescope (NTT) and the Nordic Optical Telescope (NOT), in conjunction with the SDSS-II Supernova Survey, are analysed. We use spectral indicators…

More than 3000 spectroscopically confirmed Type Ia supernovae (SNe Ia) are presented in the Zwicky Transient Facility SN Ia Data Release 2 (ZTF DR2). In this paper, we detail the spectral properties of 482 SNe Ia near maximum light, up to a…

Observations of the peculiar type Ia SN~1991bg in NGC~4374 collected at ESO--La Silla and Asiago are presented and discussed. The broad--band light curves in the early months have a narrower peak and a luminosity decline faster than other…