- ID:
- ivo://CDS.VizieR/J/ApJ/886/27
- Title:
- SNe IIP progenitors. I. LMC giant comparison sample
- Short Name:
- J/ApJ/886/27
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the evolution of massive star progenitors of supernovae of type IIP. We take the example of the nearby and well-studied SN2013ej. We explore how convective overshoot affects the stellar structure, surface abundances, and effective temperature of massive stars, using the Modules for Experiments in Stellar Astrophysics. In particular, models with moderate overshoot (f=0.02-0.031) show the presence of blue loops in the Hertzsprung-Russell diagram with a red to blue excursion (log_10_[Teff/K] from <3.6 to >4.0) and transition back to red, during the core helium-burning phase. Models with overshoot outside this range of f values kept the star in the red supergiant state throughout the post-helium-ignition phases. The surface CNO abundance shows enrichment post-main-sequence and again around the time when helium is exhausted in the core. These evolutionary changes in surface CNO abundance are indistinguishable in the currently available observations due to large observational uncertainties. However, these observations may distinguish between the ratio of surface nitrogen to oxygen at different evolutionary stages of the star. We also compare the effects of convective overshoot on various parameters related to likelihood of explosion of a star as opposed to collapse to a black hole. These parameters are the compactness parameter, M_4_, and {mu}_4_. The combination {mu}_4_xM_4_, and {mu}_4_ have similar variations with f and both peak at f=0.032. We find that all of our 13M_{sun}_ models are likely to explode.
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Search Results
- ID:
- ivo://CDS.VizieR/J/MNRAS/461/2003
- Title:
- SN 2013ej light curves 1 to 450d after explosion
- Short Name:
- J/MNRAS/461/2003
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present optical and near-infrared photometric and spectroscopic observations of SN 2013ej, in galaxy M74, from 1 to 450 d after the explosion. SN 2013ej is a hydrogen-rich supernova, classified as a Type IIL due to its relatively fast decline following the initial peak. It has a relatively high peak luminosity (absolute magnitude M_V_=-17.6) but a small ^56^Ni production of ~0.023M_{sun}_. Its photospheric evolution is similar to other Type II SNe, with shallow absorption in the H_{alpha}_ profile typical for a Type IIL. During transition to the radioactive decay tail at ~100d, we find the SN to grow bluer in B-V colour, in contrast to some other Type II supernovae. At late times, the bolometric light curve declined faster than expected from ^56^Co decay and we observed unusually broad and asymmetric nebular emission lines. Based on comparison of nebular emission lines most sensitive to the progenitor core mass, we find our observations are best matched to synthesized spectral models with a M_ZAMS_=12-15 M_{sun}_ progenitor. The derived mass range is similar to but not higher than the mass estimated for Type IIP progenitors. This is against the idea that Type IIL are from more massive stars. Observations are consistent with the SN having a progenitor with a relatively low-mass envelope.
- ID:
- ivo://CDS.VizieR/J/A+A/646/A22
- Title:
- SN 2020faa multiphotometry and spectra
- Short Name:
- J/A+A/646/A22
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present observations of SN 2020faa. This Type II supernova displays a luminous lightcurve that started to rebrighten from an initial decline. We investigate this in relation to the famous supernova iPTF14hls, which received a great deal of attention and multiple interpretations in the literature, but whose nature and source of energy still remain unknown. We demonstrate the great similarity between SN 2020faa and iPTF14hls during the first 6 months, and use this comparison to forecast the evolution of SN 2020faa and to reflect on the less well observed early evolution of iPTF14hls. We present and analyse our observational data, consisting mainly of optical lightcurves from the Zwicky Transient Facility in the gri bands and of a sequence of optical spectra. We construct colour curves and a bolometric lightcurve, and we compare ejecta-velocity and black-body radius evolutions for the two supernovae and for more typical Type II supernovae. The lightcurves show a great similarity with those of iPTF14hls over the first 6 months in luminosity, timescale, and colour. In addition, the spectral evolution of SN 2020faa is that of a Type II supernova, although it probes earlier epochs than those available for iPTF14hls. The similar lightcurve behaviour is suggestive of SN 2020faa being a new iPTF14hls. We present these observations now to advocate follow-up observations, since most of the more striking evolution of supernova iPTF14hls came later, with lightcurve undulations and a spectacular longevity. On the other hand, for SN 2020faa we have better constraints on the explosion epoch than we had for iPTF14hls, and we have been able to spectroscopically monitor it from earlier phases than was done for the more famous sibling.
- ID:
- ivo://CDS.VizieR/J/MNRAS/431/308
- Title:
- SN 2011fu BVRI light curves
- Short Name:
- J/MNRAS/431/308
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the low-resolution spectroscopic and UBVRI broad-band photometric investigations of the Type IIb supernova (SN) 2011fu, discovered in UGC 01626. The photometric follow-up of this event was initiated a few days after the explosion and covers a period of about 175d. The early-phase light curve shows a rise, followed by steep decay in all bands, and shares properties very similar to that seen for SN 1993J, with a possible detection of the adiabatic cooling phase. Modelling of the quasi-bolometric light curve suggests that the progenitor had an extended (~1x10^13^cm), low-mass (~0.1M{sun}) H-rich envelope on top of a dense, compact (~2x10^11^cm), more massive (~1.1M{sun}) He-rich core. The nickel mass synthesized during the explosion was found to be ~0.21M{sun}, slightly larger than that seen for other Type IIb SNe. The spectral modelling performed with synow suggests that the early-phase line velocities for H and Feii features were ~16000 and ~14000km/s, respectively. Then, the velocities declined up to day +40 and became nearly constant at later epochs.
- ID:
- ivo://CDS.VizieR/J/MNRAS/454/95
- Title:
- SN 2011fu UBVRI griz JHKs light curves
- Short Name:
- J/MNRAS/454/95
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present optical and near-infrared observations of the type IIb supernova (SN) 2011fu from a few days to ~300d after explosion. The SN presents a double-peaked light curve (LC) similar to that of SN 1993J, although more luminous and with a longer cooling phase after the primary peak. The spectral evolution is also similar to SN 1993J's, with hydrogen dominating the spectra to ~40d, then helium gaining strength, and nebular emission lines appearing from ~60d post-explosion. The velocities derived from the P-Cygni absorptions are overall similar to those of other type IIb SNe. We have found a strong similarity between the oxygen and magnesium line profiles at late times, which suggests that these lines are forming at the same location within the ejecta. The hydrodynamical modelling of the pseudo-bolometric LC and the observed photospheric velocities suggest that SN 2011fu was the explosion of an extended star (R~450R_{sun}_), in which 1.3x10^51^erg of kinetic energy were released and 0.15M_{sun}_ of 56Ni were synthesized. In addition, a better reproduction of the observed early pseudo-bolometric LC is achieved if a more massive H-rich envelope than for other type IIb SNe is considered (0.3M_{sun}_). The hydrodynamical modelling of the LC and the comparison of our late-time spectra with nebular spectral models for type IIb SNe, point to a progenitor for SN 2011fu with a Zero Age Main Sequence (ZAMS) mass of 13-18M_{sun}_.
- ID:
- ivo://CDS.VizieR/J/ApJ/882/L15
- Title:
- SN 2018hna photometry & spectroscopy obs.
- Short Name:
- J/ApJ/882/L15
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- High-cadence ultraviolet, optical, and near-infrared photometric and low-resolution spectroscopic observations of the peculiar Type II supernova (SN) 2018hna are presented. The early-phase multiband light curves (LCs) exhibit the adiabatic cooling envelope emission following the shock breakout up to ~14 days from the explosion. SN 2018hna has a rise time of ~88 days in the V band, similar to SN 1987A. A ^56^Ni mass of ~0.087+/-0.004M_{sun}_ is inferred for SN 2018hna from its bolometric LC. Hydrodynamical modeling of the cooling phase suggests a progenitor with a radius ~50R_{sun}_, a mass of ~14-20M_{sun}_, and an explosion energy of ~1.7-2.9x10^51^erg. The smaller inferred radius of the progenitor than a standard red supergiant is indicative of a blue supergiant progenitor of SN 2018hna. A subsolar metallicity (~0.3Z_{sun}_) is inferred for the host galaxy UGC 07534, concurrent with the low-metallicity environments of 1987A-like events.
- ID:
- ivo://CDS.VizieR/J/A+A/630/A76
- Title:
- SN2016hnk photometry and spectroscopy
- Short Name:
- J/A+A/630/A76
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a comprehensive dataset of optical and near-infrared photometry and spectroscopy of type Ia supernova (SN) 2016hnk, combined with integral field spectroscopy (IFS) of its host galaxy, MCG -01-06-070, and nearby environment. Our goal with this complete dataset is to understand the nature of this peculiar object. Methods: Properties of the SN local environment are characterized by means of single stellar population synthesis applied to IFS observations taken two years after the SN exploded. We performed detailed analyses of SN photometric data by studying its peculiar light and color curves. SN 2016hnk spectra were compared to other 1991bg-like SNe Ia, 2002es-like SNe Ia, and Ca-rich transients. In addition, we used abundance stratification modeling to identify the various spectral features in the early phase spectral sequence and also compared the dataset to a modified non-LTE model previously produced for the subluminous SN1999by. Results: SN 2016hnk is consistent with being a subluminous (MB=-16.7mag, sBV=0.43+/-0.03), highly reddened object. The IFS of its host galaxy reveals both a significant amount of dust at the SN location, residual star formation, and a high proportion of old stellar populations in the local environment compared to other locations in the galaxy, which favors an old progenitor for SN 2016hnk. Inspection of a nebular spectrum obtained one year after maximum contains two narrow emission lines attributed to the forbidden [CaII] {lambda}{lambda}7291,7324 doublet with a Doppler shift of 700km/s. Based on various observational diagnostics, we argue that the progenitor of SN 2016hnk was likely a near Chandrasekhar-mass (MCh) carbon-oxygen white dwarf that produced 0.108M_{sun}_ of 56 Ni. Our modeling suggests that the narrow [CaII] features observed in the nebular spectrum are associated with 48 Ca from electron capture during the explosion, which is expected to occur only in white dwarfs that explode near or at the MCh limit.
- ID:
- ivo://CDS.VizieR/J/ApJ/738/162
- Title:
- SN Ia candidates from the SDSS-II SN Survey
- Short Name:
- J/ApJ/738/162
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We analyze the three-year Sloan Digital Sky Survey II (SDSS-II) Supernova (SN) Survey data and identify a sample of 1070 photometric Type Ia supernova (SN Ia) candidates based on their multiband light curve data. This sample consists of SN candidates with no spectroscopic confirmation, with a subset of 210 candidates having spectroscopic redshifts of their host galaxies measured while the remaining 860 candidates are purely photometric in their identification. We describe a method for estimating the efficiency and purity of photometric SN Ia classification when spectroscopic confirmation of only a limited sample is available, and demonstrate that SN Ia candidates from SDSS-II can be identified photometrically with ~91% efficiency and with a contamination of ~6%. Although this is the largest uniform sample of SN candidates to date for studying photometric identification, we find that a larger spectroscopic sample of contaminating sources is required to obtain a better characterization of the background events. A Hubble diagram using SN candidates with no spectroscopic confirmation, but with host galaxy spectroscopic redshifts, yields a distance modulus dispersion that is only ~20%-40% larger than that of the spectroscopically confirmed SN Ia sample alone with no significant bias. A Hubble diagram with purely photometric classification and redshift-distance measurements, however, exhibits biases that require further investigation for precision cosmology.
- ID:
- ivo://CDS.VizieR/J/MNRAS/457/3470
- Title:
- SN Ia host-galaxy/cosmological parameters
- Short Name:
- J/MNRAS/457/3470
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a systematic study of the relationship between Type Ia Supernova (SN Ia) properties, and the characteristics of their host galaxies, using a sample of 581 SNe Ia from the full Sloan Digital Sky Survey II (SDSS-II) SN Survey. We also investigate the effects of this on the cosmological constraints derived from SNe Ia. Compared to previous studies, our sample is larger by a factor of >4, and covers a substantially larger redshift range (up to z~0.5), which is directly applicable to the volume of cosmological interest. We measure a significant correlation (>5{sigma}) between the host-galaxy stellar-mass and the SN Ia Hubble Residuals (HR). We find a weak correlation (1.4{sigma}) between the host-galaxy metallicity as measured from emission lines in the spectra, and the SN Ia HR. We also find evidence that the slope of the correlation between host-galaxy mass and HR is -0.11mag/log(M_host_/M_{sun}_) steeper in lower metallicity galaxies. We test the effects on a cosmological analysis using both the derived best-fitting correlations between host parameters and HR, and by allowing an additional free parameter in the fit to account for host properties which we then marginalize over when determining cosmological parameters. We see a shift towards more negative values of the equation-of-state parameter w, along with a shift to lower values of {Omega}_m_ after applying mass or metallicity corrections. The shift in cosmological parameters with host-galaxy stellar-mass correction is consistent with previous studies. We find a best-fitting cosmology of {OMEGA}_m+=0.266+/-0.016, {OMEGA}_{LAMBDA}_=0.740+/-0.018 and w=-1.151^+0.123^_-0.121_ (statistical errors only).
- ID:
- ivo://CDS.VizieR/J/ApJ/769/39
- Title:
- SN Ibn PS1-12sk optical and NIR light curves
- Short Name:
- J/ApJ/769/39
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We report on our discovery and observations of the Pan-STARRS1 supernova (SN) PS1-12sk, a transient with properties that indicate atypical star formation in its host galaxy cluster or pose a challenge to popular progenitor system models for this class of explosion. The optical spectra of PS1-12sk classify it as a Type Ibn SN (SN Ibn; cf. SN 2006jc), dominated by intermediate-width (3x10^3^km/s) and time variable He I emission. Our multi-wavelength monitoring establishes the rise time dt ~9-23 days and shows an NUV-NIR spectral energy distribution with temperature >~17x10^3^K and a peak magnitude of M_z_=-18.88+/-0.02mag. SN Ibn spectroscopic properties are commonly interpreted as the signature of a massive star (17-100M_{sun}_) explosion within an He-enriched circumstellar medium. However, unlike previous SNe Ibn, PS1-12sk is associated with an elliptical brightest cluster galaxy, CGCG 208-042 (z=0.054) in cluster RXC J0844.9+4258. The expected probability of an event like PS1-12sk in such environments is low given the measured infrequency of core-collapse SNe in red-sequence galaxies compounded by the low volumetric rate of SN Ibn. Furthermore, we find no evidence of star formation at the explosion site to sensitive limits ({Sigma}_H{alpha}_<~2x10^-3^M_{sun}_/yr/kpc2). We therefore discuss white dwarf binary systems as a possible progenitor channel for SNe Ibn. We conclude that PS1-12sk represents either a fortuitous and statistically unlikely discovery, evidence for a top-heavy initial mass function in galaxy cluster cooling flow filaments, or the first clue suggesting an alternate progenitor channel for SNe Ibn.
