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3351. SNe Ia light curves for the LSQ-CSP sample
ID:
ivo://CDS.VizieR/J/ApJS/219/13
Title:
SNe Ia light curves for the LSQ-CSP sample
Short Name:
J/ApJS/219/13
Date:
21 Oct 2021
Publisher:
CDS
Description:
The La Silla/QUEST Variability Survey (LSQ) and the Carnegie Supernova Project (CSP II) are collaborating to discover and obtain photometric light curves for a large sample of low-redshift (z<0.1) Type Ia supernovae (SNe Ia). The supernovae are discovered in the LSQ survey using the 1m ESO Schmidt telescope at the La Silla Observatory with the 10 square degree QUEST camera. The follow-up photometric observations are carried out using the 1m Swope telescope and the 2.5m du Pont telescopes at the Las Campanas Observatory. This paper describes the survey, discusses the methods of analyzing the data, and presents the light curves for the first 31 SNe Ia obtained in the survey. The SALT 2.4 supernova light-curve fitter was used to analyze the photometric data, and the Hubble diagram for this first sample is presented. The measurement errors for these supernovae averaged 4%, and their intrinsic spread was 14%.
3352. SNe Ia spectra from SNLS
ID:
ivo://CDS.VizieR/J/A+A/614/A134
Title:
SNe Ia spectra from SNLS
Short Name:
J/A+A/614/A134
Date:
21 Oct 2021
Publisher:
CDS
Description:
We aim to present 70 spectra of 68 new high-redshift type Ia supernovae (SNe Ia) measured at ESO's VLT during the final two years of operation (2006-2008) of the Supernova Legacy Survey (SNLS). This new sample complements the VLT three year spectral set. Altogether, these two data sets form the five year sample of SNLS SN Ia spectra measured at the VLT on which the final SNLS cosmological analysis will partly be based. In the redshift range considered, this sample is unique in terms of homogeneity and number of spectra. We use it to investigate the possibility of a spectral evolution of SNe Ia populations with redshift as well as SNe Ia spectral properties as a function of lightcurve fit parameters and the mass of the host-galaxy. Reduction and extraction are based on both IRAF standard tasks and our own reduction pipeline. Redshifts are estimated from host-galaxy lines whenever possible or alternatively from supernova features. We used the spectro-photometric SN Ia model SALT2 combined with a set of galaxy templates that model the host-galaxy contamination to assess the type Ia nature of the candidates. We identify 68 new SNe Ia with redshift ranging from z=0.207 to z=0.98 for an average redshift of z=0.62. Each spectrum is presented individually along with its best-fit SALT2 model. Adding this new sample to the three year VLT sample of SNLS, the final dataset contains 209 spectra corresponding to 192 SNe Ia identified at the VLT. We also publish the redshifts of other candidates (host galaxies or other transients) whose spectra were obtained at the same time as the spectra of live SNe Ia. This list provides a new redshift catalog useful for upcoming galaxy surveys. Using the full VLT SNe Ia sample, we build composite spectra around maximum light with cuts in color, the lightcurve shape parameter ("stretch"), host-galaxy mass and redshift. We find that high-z SNe Ia are bluer, brighter and have weaker intermediate mass element absorption lines than their low-z counterparts at a level consistent with what is expected from selection effects. We also find a flux excess in the range [3000-3400]{AA} for SNe Ia in low mass host-galaxies (M<10^10^M_{sun}_) or with locally blue U-V colors, and suggest that the UV flux (or local color) may be used in future cosmological studies as a third standardization parameter in addition to stretch and color.
3353. SNe II light curves & spectra from the CfA
ID:
ivo://CDS.VizieR/J/ApJS/233/6
Title:
SNe II light curves & spectra from the CfA
Short Name:
J/ApJS/233/6
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present multiband photometry of 60 spectroscopically confirmed supernovae (SNe): 39 SNe II/IIP, 19 IIn, 1 IIb, and 1 that was originally classified as a IIn but later as a Ibn. Of these, 46 have only optical photometry, 6 have only near-infrared (NIR) photometry, and 8 have both optical and NIR. The median redshift of the sample is 0.016. We also present 195 optical spectra for 48 of the 60 SN. There are 26 optical and 2 NIR light curves of SNe II/IIP with redshifts z>0.01, some of which may give rise to useful distances for cosmological applications. All photometry was obtained between 2000 and 2011 at the Fred Lawrence Whipple Observatory (FLWO), via the 1.2m and 1.3m PAIRITEL telescopes for the optical and NIR, respectively. Each SN was observed in a subset of the u'UBVRIr'i'JHK_s_ bands. There are a total of 2932 optical and 816 NIR light curve points. Optical spectra were obtained using the FLWO 1.5m Tillinghast telescope with the FAST spectrograph and the MMT Telescope with the Blue Channel Spectrograph. Our photometry is in reasonable agreement with select samples from the literature: two-thirds of our star sequences have average V offsets within +/-0.02mag and roughly three-quarters of our light curves have average differences within +/-0.04mag. The data from this work and the literature will provide insight into SN II explosions, help with developing methods for photometric SN classification, and contribute to their use as cosmological distance indicators.
3354. SNe IIP progenitors. I. LMC giant comparison sample
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.
3355. SN 2013ej light curves 1 to 450d after explosion
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.
3356. SN 2020faa multiphotometry and spectra
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.
3357. SN 2011fu BVRI light curves
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.
3358. SN 2011fu UBVRI griz JHKs light curves
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}_.
3359. SN 2018hna photometry & spectroscopy obs.
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.
3360. SN2016hnk photometry and spectroscopy
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.