ABSTRACT We present a compilation of UBVRIz light curves of 51 type II supernovae discovered during the course of four different surveys during 1986-2003: the Cerro Tololo Supernova Survey, the ...Calán/Tololo Supernova Program (C&T), the Supernova Optical and Infrared Survey (SOIRS), and the Carnegie Type II Supernova Survey (CATS). The photometry is based on template-subtracted images to eliminate any potential host galaxy light contamination, and calibrated from foreground stars. This work presents these photometric data, studies the color evolution using different bands, and explores the relation between the magnitude at maximum brightness and the brightness decline parameter (s) from maximum light through the end of the recombination phase. This parameter is found to be shallower for redder bands and appears to have the best correlation in the B band. In addition, it also correlates with the plateau duration, being shorter (longer) for larger (smaller) s values.
ABSTRACT
The environmental dependence of Type Ia supernova (SN Ia) luminosities is well established, and efforts are being made to find its origin. Previous studies typically use the currently ...observed status of the host galaxy. However, given the delay time between the birth of the progenitor star and the SN Ia explosion, the currently observed status may differ from the birth environment of the SN Ia progenitor star. In this paper, employing the chemical evolution and accurately determined stellar population properties of 44 early-type host galaxies, we, for the first time, estimate the SN Ia progenitor star birth environment, specifically Fe/HBirth and α/FeBirth. We show that α/FeBirth has a $30.4^{\text{+10.6}}_{-10.1}{{\ \rm per\ cent}}$ wider range than the currently observed α/FeCurrent, while the range of Fe/HBirth is not statistically different ($17.9^{\text{+26.0}}_{-27.1}{{\ \rm per\ cent}}$) to that of Fe/HCurrent. The birth and current environments of Fe/H and α/Fe are sampled from different populations (p-values of the Kolmogorov–Smirnov test <0.01). We find that light-curve fit parameters are insensitive to Fe/HBirth (<0.9σ for the non-zero slope), while a linear trend is observed with Hubble residuals (HRs) at the 2.4σ significance level. With α/FeBirth, no linear trends (<1.1σ) are observed. Interestingly, we find that α/FeBirth clearly splits the SN Ia sample into two groups: SN Ia exploded in α/FeBirth-rich or α/FeBirth-poor environments. SNe Ia exploded in different α/FeBirth groups have different weighted-means of light-curve shape parameters: 0.81 ± 0.33 (2.5σ). They are thought to be drawn from different populations (p-value = 0.01). Regarding SN Ia colour and HRs, there is no difference (<1.0σ) in the weighted-means and distribution (p-value > 0.27) of each α/FeBirth group.
Abstract
The diversity of Type II supernovae (SNe II) is thought to be driven mainly by differences in their progenitor’s hydrogen-rich (H-rich) envelope mass, with SNe IIP having long plateaus (∼100 ...days) and the most massive H-rich envelopes. However, it is an ongoing mystery why SNe II with short plateaus (tens of days) are rarely seen. Here, we present optical/near-infrared photometric and spectroscopic observations of luminous Type II short-plateau SNe 2006Y, 2006ai, and 2016egz. Their plateaus of about 50–70 days and luminous optical peaks (≲−18.4 mag) indicate significant pre-explosion mass loss resulting in partially stripped H-rich envelopes and early circumstellar material (CSM) interaction. We compute a large grid of
MESA
+
STELLA
single-star progenitor and light-curve models with various progenitor zero-age main-sequence (ZAMS) masses, mass-loss efficiencies, explosion energies,
56
Ni masses, and CSM densities. Our model grid shows a continuous population of SNe IIP–IIL–IIb-like light-curve morphology in descending order of H-rich envelope mass. With large
56
Ni masses (≳0.05
M
⊙
), short-plateau SNe II lie in a confined parameter space as a transitional class between SNe IIL and IIb. For SNe 2006Y, 2006ai, and 2016egz, our findings suggest high-mass red supergiant (RSG) progenitors (
M
ZAMS
≃ 18–22
M
⊙
) with small H-rich envelope masses (
) that have experienced enhanced mass loss (
) for the last few decades before the explosion. If high-mass RSGs result in rare short-plateau SNe II, then these events might ease some of the apparent underrepresentation of higher-luminosity RSGs in observed SN II progenitor samples.
ABSTRACT
In this study, we use MUSE Integral Field Spectroscopy (IFS), along with multiline diagnostics, for the optical identification of supernova remnants (SNRs) in the galaxy NGC 7793. We find in ...total 238 SNR candidates, 225 of them new identifications, increasing significantly the number of known SNRs in this galaxy. The velocity dispersion of the candidate SNRs was calculated, giving a mean value of $\rm 27\, km\, s^{-1}$. We construct the H $\rm {\alpha }$, S ii, O iii, and S ii–H $\rm {\alpha }$ luminosity functions, and for the first time, the N ii, N iI–H $\rm {\alpha }$, N ii–S ii, O iii–S ii, and O iii–N ii luminosity functions of the candidate SNRs. Shock models, along with the observed multiline information were used, in order to estimate shock velocities. The $\rm \sim 65{{\ \rm per\ cent}}$ of the SNRs present velocities < 300 $\rm km\, s^{-1}$. There is a clear correlation between shock velocity and O iii/H $\rm {\beta }$ ratio, and a less clear but still evident correlation in the relation between shock velocity and the S ii/H $\rm {\alpha }$, N ii/H $\rm {\alpha }$ ratios. We also use the S ii6716/31 ratio of the SNR candidates to calculate their post-shock density, assuming different temperatures. The median value of the density of our sample is $\rm \sim 80\, cm^{-3}$, for a temperature of $\rm T = 10^4\, K$. No correlation between shock velocity and density, or density and SNRs with S ii/H $\rm {\alpha }$ > 0.4 and S ii/H $\rm {\alpha }$ < 0.4 is observed.
This paper describes the data release of the Sloan Digital Sky Survey-II (SDSS-II) Supernova Survey conducted between 2005 and 2007. Light curves, spectra, classifications, and ancillary data are ...presented for 10,258 variable and transient sources discovered through repeat ugriz imaging of SDSS Stripe 82, a 300 deg2 area along the celestial equator. This data release is comprised of all transient sources brighter than r 22.5 mag with no history of variability prior to 2004. Dedicated spectroscopic observations were performed on a subset of 889 transients, as well as spectra for thousands of transient host galaxies using the SDSS-III BOSS spectrographs. Photometric classifications are provided for the candidates with good multi-color light curves that were not observed spectroscopically, using host galaxy redshift information when available. From these observations, 4607 transients are either spectroscopically confirmed, or likely to be, supernovae, making this the largest sample of supernova candidates ever compiled. We present a new method for SN host-galaxy identification and derive host-galaxy properties including stellar masses, star formation rates, and the average stellar population ages from our SDSS multi-band photometry. We derive SALT2 distance moduli for a total of 1364 SN Ia with spectroscopic redshifts as well as photometric redshifts for a further 624 purely photometric SN Ia candidates. Using the spectroscopically confirmed subset of the three-year SDSS-II SN Ia sample and assuming a flat ΛCDM cosmology, we determine M = 0.315 0.093 (statistical error only) and detect a non-zero cosmological constant at 5.7 .
Abstract
We analyze 143 Type Ia supernovae (SNe Ia) observed in
H
band (1.6–1.8
μ
m) and find that SNe Ia are intrinsically brighter in
H
band with increasing host galaxy stellar mass. We find that ...SNe Ia in galaxies more massive than 10
10.43
M
⊙
are 0.13 ± 0.04 mag brighter in
H
than SNe Ia in less massive galaxies. The same set of SNe Ia observed at optical wavelengths, after width–color–luminosity corrections, exhibit a 0.10 ± 0.03 mag offset in the Hubble residuals. We observe an outlier population (
∣
Δ
H
max
∣
>
0.5
mag) in the
H
band and show that removing the outlier population moves the mass threshold to 10
10.65
M
⊙
and reduces the step in
H
band to 0.08 ± 0.04 mag, but the equivalent optical mass step is increased to 0.13 ± 0.04 mag. We conclude that the outliers do not drive the brightness–host-mass correlation. Less massive galaxies preferentially host more higher-stretch SNe Ia, which are intrinsically brighter and bluer. It is only after correction for width–luminosity and color–luminosity relationships that SNe Ia have brighter optical Hubble residuals in more massive galaxies. Thus, finding that SNe Ia are intrinsically brighter in
H
in more massive galaxies is an opposite correlation to the intrinsic (pre-width–luminosity correction) optical brightness. If dust and the treatment of intrinsic color variation were the main driver of the host galaxy mass correlation, we would not expect a correlation of brighter
H
-band SNe Ia in more massive galaxies.
Abstract
More luminous Type Ia supernovae prefer less massive hosts and regions of higher star formation. This correlation is inverted during width–color–luminosity light-curve standardization ...resulting in step-like biases of distance measurements with respect to host properties. Using the PMAS/PPak Integral-field Supernovahosts COmpilation (PISCO) supernova host sample and Sloan Digital Sky Survey, Galaxy Evolution Explorer, and Two Micron All Sky Survey photometry, we compare host stellar mass and specific star-formation rate (sSFR) from different observation methods, including local versus global, and fitting techniques to measure their impact on the host step biases. Mass-step measurements for all our mass samples are consistent within a 1
σ
significance from −0.03 ± 0.02 mag to −0.04 ± 0.02 mag. Including or excluding UV information had no effect on measured mass-step size or location. sSFR step sizes are more significant than mass-step measurements and varied from 0.05 ± 0.03 mag (Hα) and 0.06 ± 0.02 mag (UV) for a 51 host sample. The sSFR step location is influenced by the mass sample used to normalize star formation and by sSFR tracer choice. The step size is reduced to 0.04 ± 0.03 mag when using all available 73 hosts with Hα measurements. This 73 PISCO host subsample overall lacked a clear step signal, but here we are searching for whether different choices of mass or sSFR estimation can create a step signal. We find no evidence that different observation or fitting techniques choices can create a distance measurement step in either mass or sSFR.
PDF
