scholarly journals Light-curve properties of SN 2017fgc and HV SNe Ia

2021 ◽  
Vol 502 (3) ◽  
pp. 4112-4124
Author(s):  
Umut Burgaz ◽  
Keiichi Maeda ◽  
Belinda Kalomeni ◽  
Miho Kawabata ◽  
Masayuki Yamanaka ◽  
...  
Keyword(s):  
Light Curve ◽  
Near Infrared ◽  
Light Curves ◽  
Normal Velocity ◽  
External Effects ◽  
Band Maximum ◽  
Bolometric Luminosity ◽  
V Band ◽  
Photometric And Spectroscopic Observations ◽  
Type Ia

ABSTRACT Photometric and spectroscopic observations of Type Ia supernova (SN) 2017fgc, which cover the period from −12 to + 137 d since the B-band maximum are presented. SN 2017fgc is a photometrically normal SN Ia with the luminosity decline rate, Δm15(B)true  = 1.10 ± 0.10 mag. Spectroscopically, it belongs to the high-velocity (HV) SNe Ia group, with the Si ii λ6355 velocity near the B-band maximum estimated to be 15 200 ± 480 km s−1. At the epochs around the near-infrared secondary peak, the R and I bands show an excess of ∼0.2-mag level compared to the light curves of the normal velocity (NV) SNe Ia. Further inspection of the samples of HV and NV SNe Ia indicates that the excess is a generic feature among HV SNe Ia, different from NV SNe Ia. There is also a hint that the excess is seen in the V band, both in SN 2017fgc and other HV SNe Ia, which behaves like a less prominent shoulder in the light curve. The excess is not obvious in the B band (and unknown in the U band), and the colour is consistent with the fiducial SN colour. This might indicate that the excess is attributed to the bolometric luminosity, not in the colour. This excess is less likely caused by external effects, like an echo or change in reddening but could be due to an ionization effect, which reflects an intrinsic, either distinct or continuous, difference in the ejecta properties between HV and NV SNe Ia.

scholarly journals Rapidly Declining Hostless Type Ia Supernova KSP-OT-201509b from the KMTNet Supernova Program: Transitional Nature and Constraint on 56Ni Distribution and Progenitor Type

2021 ◽  
Vol 910 (2) ◽  
pp. 151
Author(s):  
Dae-Sik Moon ◽  
Yuan Qi Ni ◽  
Maria R. Drout ◽  
Santiago González-Gaitán ◽  
Niloufar Afsariardchi ◽  
...  
Keyword(s):  
Light Curve ◽  
Radioactive Decay ◽  
Light Curves ◽  
Host Galaxy ◽  
Curve Evolution ◽  
Sensitivity Limit ◽  
Bolometric Luminosity ◽  
Type Ia Supernova ◽  
Type Ia ◽  
High Cadence

Abstract We report the early discovery and multicolor (BVI) high-cadence light-curve analyses of the rapidly declining sub-Chandrasekhar Type Ia supernova KSP-OT-201509b (= AT 2015cx) from the KMTNet Supernova Program. The Phillips and color stretch parameters of KSP-OT-201509b are ΔM B,15 ≃ 1.62 mag and s BV ≃ 0.54, respectively, at an inferred redshift of 0.072. These, together with other measured parameters (such as the strength of the secondary I-band peak, colors, and luminosity), identify the source to be a rapidly declining Type Ia of a transitional nature that is closer to Branch-normal than 91bg-like. Its early light-curve evolution and bolometric luminosity are consistent with those of homologously expanding ejecta powered by radioactive decay and a Type Ia SN explosion with 0.32 ± 0.01 M ⊙ of synthesized 56Ni mass, 0.84 ± 0.12 M ⊙ of ejecta mass, and (0.61 ± 0.14) × 1051 erg of ejecta kinetic energy. While its B − V and V − I colors evolve largely synchronously with the changes in the I-band light curve, as found in other supernovae, we also find the presence of an early redward evolution in V − I prior to −10 days since peak. The bolometric light curve of the source is compatible with a stratified 56Ni distribution extended to shallow layers of the exploding progenitor. Comparisons between the observed light curves and those predicted from ejecta–companion interactions clearly disfavor Roche lobe–filling companion stars at large separation distances, thus supporting a double-degenerate scenario for its origin. The lack of any apparent host galaxy in our deep stack images reaching a sensitivity limit of ∼28 mag arcsec−2 makes KSP-OT-201509b a hostless Type Ia supernova and offers new insights into supernova host galaxy environments.

scholarly journals Constraints on the density distribution of type Ia supernovae ejecta inferred from late-time light-curve flattening

2020 ◽  
Vol 493 (4) ◽  
pp. 5617-5624
Author(s):  
Doron Kushnir ◽  
Eli Waxman
Keyword(s):  
Light Curve ◽  
Weighted Average ◽  
Far Infrared ◽  
Average Density ◽  
Light Curves ◽  
Type Ia Supernovae ◽  
Late Time ◽  
Simple Method ◽  
Type Ia ◽  
Ia Supernovae

ABSTRACT The finite time, τdep, over which positrons from β+ decays of 56Co deposit energy in type Ia supernovae ejecta lead, in case the positrons are trapped, to a slower decay of the bolometric luminosity compared to an exponential decline. Significant light-curve flattening is obtained when the ejecta density drops below the value for which τdep equals the 56Co lifetime. We provide a simple method to accurately describe this ‘delayed deposition’ effect, which is straightforward to use for analysis of observed light curves. We find that the ejecta heating is dominated by delayed deposition typically from 600 to 1200 d, and only later by longer lived isotopes 57Co and 55Fe decay (assuming solar abundance). For the relatively narrow 56Ni velocity distributions of commonly studied explosion models, the modification of the light curve depends mainly on the 56Ni mass-weighted average density, 〈ρ〉t3. Accurate late-time bolometric light curves, which may be obtained with JWST far-infrared (far-IR) measurements, will thus enable to discriminate between explosion models by determining 〈ρ〉t3 (and the 57Co and 55Fe abundances). The flattening of light curves inferred from recent observations, which is uncertain due to the lack of far-IR data, is readily explained by delayed deposition in models with $\langle \rho \rangle t^{3} \approx 0.2\, \mathrm{M}_{\odot }\, (10^{4}\, \textrm{km}\, \textrm{s}^{-1})^{-3}$, and does not imply supersolar 57Co and 55Fe abundances.

scholarly journals Observations of the low-luminosity Type Iax supernova 2019gsc: a fainter clone of SN 2008ha?

2020 ◽  
Vol 496 (2) ◽  
pp. 1132-1143 ◽  
Author(s):  
Lina Tomasella ◽  
Maximilian Stritzinger ◽  
Stefano Benetti ◽  
Nancy Elias-Rosa ◽  
Enrico Cappellaro ◽  
...  
Keyword(s):  
Light Curve ◽  
Host Galaxy ◽  
Late Time ◽  
Spectral Features ◽  
Data Set ◽  
Oxygen Abundance ◽  
Band Maximum ◽  
Photometric And Spectroscopic Observations ◽  
Decline Rate ◽  
Peak Luminosity

ABSTRACT We present optical photometric and spectroscopic observations of the faint-and-fast evolving Type Iax supernova (SN) 2019gsc, extending from the time of g-band maximum until about 50 d post-maximum, when the object faded to an apparent r-band magnitude mr = 22.48 ± 0.11 mag. SN 2019gsc reached a peak luminosity of only Mg = −13.58 ± 0.15 mag, and is characterized with a post-maximum decline rate Δm15(g) = 1.08 ± 0.14 mag. These light curve parameters are comparable to those measured for SN 2008ha of Mg = −13.89 ± 0.14 mag at peak and Δm15(g) =1.80 ± 0.03 mag. The spectral features of SN 2019gsc also resemble those of SN 2008ha at similar phases. This includes both the extremely low ejecta velocity at maximum, ∼3000 km s−1, and at late-time (phase +54 d) strong forbidden iron and cobalt lines as well as both forbidden and permitted calcium features. Furthermore, akin to SN 2008ha, the bolometric light curve of SN 2019gsc is consistent with the production of ≈0.003 ± 0.001 M⊙ of 56Ni. The explosion parameters, Mej ≈ 0.13 M⊙ and Ek ≈ 12 × 1048 erg, are also similar to those inferred for SN 2008ha. We estimate a subsolar oxygen abundance for the host galaxy of SN 2019gsc (12  + log10(O/H) =8.10 ± 0.18 dex), consistent with the equally metal-poor environment of SN 2008ha. Altogether, our data set for SN 2019gsc indicates that this is a member of a small but growing group of extreme SN Iax that includes SN 2008ha and SN 2010ae.

scholarly journals Type Ia supernova Hubble diagram with near-infrared and optical observations

2018 ◽  
Vol 615 ◽  
pp. A45 ◽  
Author(s):  
V. Stanishev ◽  
A. Goobar ◽  
R. Amanullah ◽  
B. Bassett ◽  
Y. T. Fantaye ◽  
...  
Keyword(s):  
Near Infrared ◽  
Optical Observations ◽  
Optical Data ◽  
Host Galaxies ◽  
Hubble Diagram ◽  
Single Observation ◽  
Band Maximum ◽  
Nonlinear Part ◽  
Type Ia ◽  
Optical Wavelengths

Context. Type Ia Supernovae (SNe Ia) have been used as standardizable candles in the optical wavelengths to measure distances with an accuracy of ~7% out to redshift z ~ 1.5. There is evidence that in the near-infrared (NIR) wavelengths SNe Ia are even better standard candles, however, NIR observations are much more time-consuming. Aims. We aim to test whether the NIR peak magnitudes could be accurately estimated with only a single observation obtained close to maximum light, provided that the time of B band maximum, the B − V color at maximum and the optical stretch parameter are known. Methods. We present multi-epoch UBV RI and single-epoch J and H photometric observations of 16 SNe Ia in the redshift range z = 0.037 − 0.183, doubling the leverage of the current SN Ia NIR Hubble diagram and the number of SNe beyond redshift 0.04. This sample was analyzed together with 102 NIR and 458 optical light curves (LCs) of normal SNe Ia from the literature. Results. The analysis of 45 NIR LCs with well-sampled first maximum shows that a single template accurately describes the LCs if its time axis is stretched with the optical stretch parameter. This allows us to estimate the peak NIR magnitudes of SNe with only few observations obtained within ten days from B-band maximum. The NIR Hubble residuals show weak correlation with ΔM15 and the color excess E(B − V), and for the first time we report a potential dependence on the Jmax − Hmax color. With these corrections, the intrinsic NIR luminosity scatter of SNe Ia is estimated to be ~0.10 mag, which is smaller than what can be derived for a similarly heterogeneous sample at optical wavelengths. Analysis of both NIR and optical data shows that the dust extinction in the host galaxies corresponds to a low RV ≃ 1.8–1.9. Conclusions. We conclude that SNe Ia are at least as good standard candles in the NIR as in the optical and are potentially less affected by systematic uncertainties. We extended the NIR SN Ia Hubble diagram to its nonlinear part at z ~ 0.2 and confirmed that it is feasible to accomplish this result with very modest sampling of the NIR LCs, if complemented by well-sampled optical LCs. With future facilities it will be possible to extend the NIR Hubble diagram beyond redshift z ≃ 1, and our results suggest that the most efficient way to achieve this would be to obtain a single observation close to the NIR maximum.

scholarly journals New near-infrared JHKs light-curve templates for RR Lyrae variables

2019 ◽  
Vol 625 ◽  
pp. A1 ◽  
Author(s):  
V. F. Braga ◽  
P. B. Stetson ◽  
G. Bono ◽  
M. Dall’Ora ◽  
I. Ferraro ◽  
...  
Keyword(s):  
Light Curve ◽  
Near Infrared ◽  
Large Magellanic Cloud ◽  
Light Curves ◽  
Anchor Point ◽  
Phase Point ◽  
Pulsation Period ◽  
Rr Lyrae ◽  
The Mean ◽  
The Difference

We provide homogeneous optical (UBVRI) and near-infrared (NIR, JHK) time series photometry for 254 cluster (ω Cen, M 4) and field RR Lyrae (RRL) variables. We ended up with more than 551 000 measurements, of which only 9% are literature data. For 94 fundamental (RRab) and 51 first overtones (RRc) we provide a complete optical/NIR characterization (mean magnitudes, luminosity amplitudes, epoch of the anchor point). The NIR light curves of these variables were adopted to provide new light-curve templates for both RRc and RRab variables. The templates for the J and the H bands are newly introduced, together with the use of the pulsation period to discriminate among the different RRab templates. To overcome subtle uncertainties in the fit of secondary features of the light curves we provide two independent sets of analytical functions (Fourier and periodic Gaussian series). The new templates were validated by using 26 ω Cen and Bulge RRLs. We find that the difference between the measured mean magnitude along the light curve and the mean magnitude estimated by using the template on a single randomly extracted phase point is better than 0.01 mag (σ = 0.04 mag). We also validated the template on variables for which at least three phase points were available, but without information on the phase of the anchor point. We find that the accuracy of the mean magnitudes is also ∼0.01 mag (σ = 0.04 mag). The new templates were applied to the Large Magellanic Cloud (LMC) globular cluster Reticulum and by using literature data and predicted PLZ relations we find true distance moduli μ = 18.47 ± 0.10 (rand.) ± 0.03 (syst.) mag (J) and 18.49 ± 0.09 ± 0.05 mag (K). We also used literature optical and mid-infrared data and we found a mean μ of 18.47 ± 0.02 ± 0.06 mag, suggesting that Reticulum is ∼1 kpc closer than the LMC.

scholarly journals Expected Changes of SNe with Redshift due to Evolution of Their Progenitors

2005 ◽  
Vol 192 ◽  
pp. 567-572
Author(s):  
Inma Domínguez ◽  
Peter Höflich ◽  
Oscar Straniero ◽  
Marco Limongi ◽  
Alessandro Chieffi
Keyword(s):  
Light Curve ◽  
Main Sequence ◽  
High Redshift ◽  
Stellar Populations ◽  
Light Curves ◽  
Type Ii ◽  
First Stars ◽  
Metal Free ◽  
Standard Candle ◽  
Type Ia

SummaryWe have analyzed the influence of the stellar populations, from which SN progenitors come, on the observational outcome, including the metal free Pop. III. We use our models to study the evolution of the progenitor, the subsequent explosion and the light curves. For Type Ia, the variation of the main sequence mass of the progenitor of the exploding WD produces an offset in the maximum-decline relation of 0.2 mag. This effect is critical for the use of high redshift Type Ia SNe as cosmological standard candles. In contrast, the metallicity does not change the above relation (at maximum, ΔMV ≤0.06 mag). For Type II, we find a dependence of the light curve properties with both main sequence mass and metallicity of the progenitor, and we identify a rather homogeneous subclass, “Extreme II-P,” that may be used as a quasi-standard candle. Note that, although not as good as Type Ia for distance determinations, Type II are expected to have occurred since the first stars were formed.

scholarly journals The Type II supernovae 2006V and 2006au: two SN 1987A-like events

2011 ◽  
Vol 7 (S279) ◽  
pp. 403-404
Author(s):  
Francesco Taddia
Keyword(s):  
Light Curve ◽  
Near Infrared ◽  
Light Curves ◽  
Type Ii ◽  
Host Galaxies ◽  
Remarkable Similarity ◽  
Sn 1987A ◽  
Nir Light ◽  
Initial Dip ◽  
Analytic Models

AbstractWe studied optical and near-infrared (NIR) light curves, and optical spectra of Supernovae (SNe) 2006V and 2006au, two objects monitored by the Carnegie Supernova Project (CSP) and displaying remarkable similarity to SN 1987A, although they were brighter, bluer and with higher expansion velocities. SN 2006au also shows an initial dip in the light curve, which we have interpreted as the cooling tail of the shock break-out. By fitting semi-analytic models to the UVOIR light curve of each object, we derive the physical properties of the progenitors and we conclude that SNe 2006V and 2006au were most likely Blue Supergiant (BSG) stars that exploded with larger energies as compared to that of SN 1987A. We are currently investigating the host galaxies of a few BSG SNe, in order to understand the role played by the metallicity in the production of these rare exploding BSG stars.

scholarly journals SN 2012fr: Ultraviolet, Optical, and Near-infrared Light Curves of a Type Ia Supernova Observed within a Day of Explosion

2018 ◽  
Vol 859 (1) ◽  
pp. 24 ◽  
Author(s):  
Carlos Contreras ◽  
M. M. Phillips ◽  
Christopher R. Burns ◽  
Anthony L. Piro ◽  
B. J. Shappee ◽  
...  
Keyword(s):  
Near Infrared ◽  
Light Curves ◽  
Infrared Light ◽  
Near Infrared Light ◽  
Type Ia Supernova ◽  
Type Ia

scholarly journals A year-long plateau in the late-time near-infrared light curves of type Ia supernovae

2019 ◽  
Vol 4 (2) ◽  
pp. 188-195 ◽  
Author(s):  
O. Graur ◽  
K. Maguire ◽  
R. Ryan ◽  
M. Nicholl ◽  
A. Avelino ◽  
...  
Keyword(s):  
Near Infrared ◽  
Light Curves ◽  
Infrared Light ◽  
Type Ia Supernovae ◽  
Late Time ◽  
Near Infrared Light ◽  
Type Ia ◽  
Ia Supernovae
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