- ID:
- ivo://CDS.VizieR/J/MNRAS/454/3816
- Title:
- Cobalt emission in nebular phase spectra
- Short Name:
- J/MNRAS/454/3816
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The light curves of Type Ia supernovae (SNe Ia) are powered by the radioactive decay of ^56^Ni to ^56^Co at early times, and the decay of ^56^Co to ^56^Fe from ~60 d after explosion. We examine the evolution of the [CoIII] {lambda}5893 emission complex during the nebular phase for SNe Ia with multiple nebular spectra and show that the line flux follows the square of the mass of ^56^Co as a function of time. This result indicates both efficient local energy deposition from positrons produced in ^56^Co decay and long-term stability of the ionization state of the nebula. We compile SN Ia nebular spectra from the literature and present 21 new late-phase spectra of 7 SNe Ia, including SN 2014J. From these we measure the flux in the [CoIII] {lambda}5893 line and remove its well-behaved time dependence to infer the initial mass of ^56^Ni (M_Ni_) produced in the explosion. We then examine ^56^Ni yields for different SN Ia ejected masses (M_ej_ - calculated using the relation between light-curve width and ejected mass) and find that the ^56^Ni masses of SNe Ia fall into two regimes: for narrow light curves (low stretch s~0.7-0.9), M_Ni_ is clustered near M_Ni_~0.4M_{sun}_ and shows a shallow increase as M_ej_ increases from ~1 to 1.4M_{sun}_; at high stretch, M_ej_ clusters at the Chandrasekhar mass (1.4M_{sun}_) while M_Ni_ spans a broad range from 0.6 to 1.2M_{sun}_. This could constitute evidence for two distinct SN Ia explosion mechanisms.
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Search Results
- ID:
- ivo://CDS.VizieR/II/214A
- Title:
- Combined General Catalogue of Variable Stars
- Short Name:
- II/214A
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The GCVS is the only reference source on all known variable stars. This version contains all of the electronically-readable version as distributed by the Sternberg Astronomical Institute and Institute of Astronomy (Russian Acad.Sci.), Moscow. It includes the catalog of variable stars, updated and completed with the seven Name-Lists of Variables Stars Nos.67-73 (see IBVS No.2681,1985; No.3058,1987; No.3323,1989; No.3530,1990; No.3840,1993; No.4140,1995; No.4471,1997), a catalog of suspected variables, a cross-index of variable star names, a catalog of extragalactic variables, and a catalog of supernovae.
- ID:
- ivo://CDS.VizieR/II/250
- Title:
- Combined General Catalogue of Variable Stars
- Short Name:
- II/250
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The GCVS is the only reference source on all known variable stars. This version contains all of the electronically-readable version as distributed by the Sternberg Astronomical Institute and Institute of Astronomy (Russian Acad.Sci.), Moscow. It includes the catalog of variable stars, updated and completed with the Name-Lists of Variables Stars Nos.67-77 (see IBVS No.2681,1985; No.3058,1987; No.3323,1989; No.3530,1990; No.3840,1993; No.4140,1995; No.4471,1997; No.4659, 1999; No.4870, 2000; No.5135, 2001; No.5422, 2003) a catalog of suspected variables, a cross-index of variable star names, a catalog of extragalactic variables, and a catalog of supernovae.
- ID:
- ivo://CDS.VizieR/J/A+A/624/A116
- Title:
- Constraints on the progenitor of SN 1987A
- Short Name:
- J/A+A/624/A116
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- With the same method as used previously, we investigate neutrino-driven explosions of a larger sample of blue supergiant models. The blue supergiants were evolved as single-star progenitors. The larger sample includes three new presupernova stars. The results are compared with light-curve observations of the peculiar type IIP SN 1987A. The explosions were modeled in 3D with the neutrino-hydrodynamics code PROMETHEUS-HOTB, and light-curve calculations were performed in spherical symmetry with the radiation-hydrodynamics code CRAB, starting at a stage of nearly homologous expansion. Our results confirm the basic findings of the previous work: 3D neutrino-driven explosions with SN 1987A-like energies synthesize an amount of Ni-56 that is consistent with the radioactive tail of the light curve. Moreover, the models mix hydrogen inward to minimum velocities below 400km/s as required by spectral observations and a 3D analysis of molecular hydrogen in SN 1987A. Hydrodynamic simulations with the new progenitor models, which possess smaller radii than the older ones, show much better agreement between calculated and observed light curves in the initial luminosity peak and during the first 20 days. A set of explosions with similar energies demonstrated that a high growth factor of Rayleigh-Taylor instabilities at the (C+O)/He composition interface combined with a weak interaction of fast Rayleigh-Taylor plumes, where the reverse shock occurs below the He/H interface, provides a sufficient condition for efficient outward mixing of Ni-56 into the hydrogen envelope. This condition is realized to the required extent only in one of the older stellar models, which yielded a maximum velocity of around 3000km/s for the bulk of ejected Ni-56, but failed to reproduce the helium-core mass of 6M_{sun}_ inferred from the absolute luminosity of the presupernova star. We conclude that none of the single-star progenitor models proposed for SN 1987A to date satisfies all constraints set by observations.
- ID:
- ivo://CDS.VizieR/J/ApJ/759/107
- Title:
- Core-collapse SNe and host galaxies
- Short Name:
- J/ApJ/759/107
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We have used images and spectra of the Sloan Digital Sky Survey to examine the host galaxies of 519 nearby supernovae (SN). The colors at the sites of the explosions, as well as chemical abundances, and specific star formation rates (SFRs) of the host galaxies provide circumstantial evidence on the origin of each SN type. We examine separately SN II, SN IIn, SN IIb, SN Ib, SN Ic, and SN Ic with broad lines (SN Ic-BL). For host galaxies that have multiple spectroscopic fibers, we select the fiber with host radial offset most similar to that of the SN. Type Ic SN explode at small host offsets, and their hosts have exceptionally strongly star-forming, metal-rich, and dusty stellar populations near their centers. The SN Ic-BL and SN IIb explode in exceptionally blue locations, and, in our sample, we find that the host spectra for SN Ic-BL show lower average oxygen abundances than those for SN Ic. SN IIb host fiber spectra are also more metal-poor than those for SN Ib, although a significant difference exists for only one of two strong-line diagnostics. SN Ic-BL host galaxy emission lines show strong central specific SFRs. In contrast, we find no strong evidence for different environments for SN IIn compared to the sites of SN II. Because our SN sample is constructed from a variety of sources, there is always a risk that sampling methods can produce misleading results. We have separated the SN discovered by targeted surveys from those discovered by galaxy-impartial searches to examine these questions and show that our results do not depend sensitively on the discovery technique.
- ID:
- ivo://CDS.VizieR/J/MNRAS/436/774
- Title:
- Core collapse supernovae (type Ibc)
- Short Name:
- J/MNRAS/436/774
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The progenitors of many Type II core-collapse supernovae (SNe) have now been identified directly on pre-discovery imaging. Here, we present an extensive search for the progenitors of Type Ibc SNe in all available pre-discovery imaging since 1998. There are 12 Type Ibc SNe with no detections of progenitors in either deep ground-based or Hubble Space Telescope archival imaging. The deepest absolute BVR magnitude limits are between -4 and -5mag. We compare these limits with the observed Wolf-Rayet population in the Large Magellanic Cloud and estimate a 16 percent probability that we have failed to detect such a progenitor by chance. Alternatively, the progenitors evolve significantly before core-collapse or we have underestimated the extinction towards the progenitors. Reviewing the relative rates and ejecta mass estimates from light-curve modelling of Ibc SNe, we find both incompatible with Wolf-Rayet stars with initial masses >25M_{sun}_ being the only progenitors. We present binary evolution models that fit these observational constraints. Stars in binaries with initial masses <~20M_{sun}_ lose their hydrogen envelopes in binary interactions to become low-mass helium stars. They retain a low-mass hydrogen envelope until ~10^4^yr before core-collapse; hence, it is not surprising that Galactic analogues have been difficult to identify.
- ID:
- ivo://CDS.VizieR/J/ApJ/900/140
- Title:
- CSP-II: sp. obs. of the 03fg-like SN Ia LSQ14fmg
- Short Name:
- J/ApJ/900/140
- Date:
- 02 Feb 2022 11:26:50
- Publisher:
- CDS
- Description:
- The Type Ia supernova (SN Ia) LSQ14fmg exhibits exaggerated properties that may help to reveal the origin of the "super-Chandrasekhar" (or 03fg-like) group. The optical spectrum is typical of a 03fg-like SNIa, but the light curves are unlike those of any SNe Ia observed. The light curves of LSQ14fmg rise extremely slowly. At -23 rest-frame days relative to B-band maximum, LSQ14fmg is already brighter than M_V_=-19mag before host extinction correction. The observed color curves show a flat evolution from the earliest observation to approximately 1 week after maximum. The near-infrared light curves peak brighter than -20.5mag in the J and H bands, far more luminous than any 03fg-like SNe Ia with near-infrared observations. At 1 month past maximum, the optical light curves decline rapidly. The early, slow rise and flat color evolution are interpreted to result from an additional excess flux from a power source other than the radioactive decay of the synthesized 56Ni. The excess flux matches the interaction with a typical superwind of an asymptotic giant branch (AGB) star in density structure, mass-loss rate, and duration. The rapid decline starting at around 1 month past B-band maximum may be an indication of rapid cooling by active carbon monoxide (CO) formation, which requires a low-temperature and high-density environment. These peculiarities point to an AGB progenitor near the end of its evolution and the core degenerate scenario as the likely explosion mechanism for LSQ14fmg.
- ID:
- ivo://CDS.VizieR/J/A+A/609/A134
- Title:
- CSP-I photometry for 34 supernovae
- Short Name:
- J/A+A/609/A134
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The first phase of the Carnegie Supernova Project (CSP-I) was a dedicated supernova follow-up program based at the Las Campanas Observatory that collected science data of young, low-redshift supernovae between 2004 and 2009. Presented in this paper is the CSP-I photometric data release of low-redshift stripped-envelope core-collapse supernovae. The data consist of optical (uBgV ri) photometry of 34 objects, with a subset of 26 having near-infrared (YJH) photometry. Twenty objects have optical pre-maximum coverage with a subset of 12 beginning at least five days prior to the epoch of B-band maximum brightness. In the near-infrared, 17 objects have pre-maximum observations with a subset of 14 beginning at least five days prior to the epoch of J-band maximum brightness. Analysis of this photometric data release is presented in companion papers focusing on techniques to estimate host-galaxy extinction (Stritzinger et al., submitted) and the light-curve and progenitor star properties of the sample (Taddia et al., submitted). The analysis of an accompanying visual-wavelength spectroscopy sample of ~150 spectra will be the subject of a future paper.
- ID:
- ivo://CDS.VizieR/J/ApJ/795/142
- Title:
- Defining photometric peculiar SNe Ia
- Short Name:
- J/ApJ/795/142
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- 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 the absence of a secondary peak in redder filters. This method is capable of selecting this sub-group from the normal type Ia population. Furthermore, we find that recently identified peculiar sub-types such as SNe Iax and super-Chandrasekhar SNe Ia have photometric characteristics similar to 91bg-like SNe Ia, namely, the absence of secondary maxima and shoulders at longer wavelengths, and can also be classified with our technique. The similarity of these different SN Ia sub-groups perhaps suggests common physical conditions. This typing methodology permits the photometric identification of peculiar SNe Ia in large upcoming wide-field surveys either to study them further or to obtain a pure sample of normal SNe Ia for cosmological studies.
- ID:
- ivo://CDS.VizieR/J/A+A/429/559
- Title:
- Diffuse Interstellar Bands in NGC 1448
- Short Name:
- J/A+A/429/559
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present spectroscopic VLT/UVES observations of two emerging supernovae, the Type Ia SM 2001el and the Type II SN 2003hn, in the spiral galaxy NGC 1448. Our high resolution and high signal-to-noise spectra display atomic lines of Ca II, Na I, Ti II and K I in the host galaxy. In the line of sight towards SN 2001el, we also detect over a dozen diffuse interstellar bands (DIBs) within NGC 1448.
