- 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.
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Search Results
- ID:
- ivo://CDS.VizieR/J/ApJ/740/92
- Title:
- SN.Ia host galaxies properties
- Short Name:
- J/ApJ/740/92
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We improve estimates of the stellar mass and mass-weighted average age of Type Ia supernova (SN Ia) host galaxies by combining UV and near-IR photometry with optical photometry in our analysis. Using 206 SNe Ia drawn from the full three-year Sloan Digital Sky Survey (SDSS-II) Supernova Survey and multi-wavelength host-galaxy photometry from SDSS, the Galaxy Evolution Explorer, and the United Kingdom Infrared Telescope Infrared Deep Sky Survey, we present evidence of a correlation (1.9{sigma} confidence level) between the residuals of SNe Ia about the best-fit Hubble relation and the mass-weighted average age of their host galaxies. The trend is such that older galaxies host SNe Ia that are brighter than average after standard light-curve corrections are made. We also confirm, at the 3.0{sigma} level, the trend seen by previous studies that more massive galaxies often host brighter SNe Ia after light-curve correction.
- ID:
- ivo://CDS.VizieR/J/ApJ/755/61
- Title:
- SN Ia host galaxies SFR from SDSS-II
- Short Name:
- J/ApJ/755/61
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Using data from the Sloan Digital Sky Supernova Survey-II (SDSS-II SN Survey, Frieman et al., 2008AJ....135..338F), we measure the rate of Type Ia supernovae (SNe Ia) as a function of galaxy properties at intermediate redshift. A sample of 342 SNe Ia with 0.05<z<0.25 is constructed. Using broadband photometry and redshifts, we use the P\'EGASE.2 spectral energy distributions to estimate host galaxy stellar masses and recent star formation rates (SFRs).
- 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/MNRAS/435/1680
- Title:
- SN Ia host galaxy properties
- Short Name:
- J/MNRAS/435/1680
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We study the stellar populations of Type Ia supernova (SN Ia) host galaxies using Sloan Digital Sky Survey (SDSS)-II spectroscopy. The main focus is on the relationships of SN Ia properties with stellar velocity dispersion and the stellar population parameters age, metallicity and element abundance ratios. We concentrate on a sub-sample of 84 SNe Ia from the SDSS-II Supernova Survey and find that SALT2 stretch factor values show the strongest dependence on stellar population age. Hence, more luminous SNe Ia appear in younger stellar progenitor systems. No statistically significant trends in the Hubble residual with any of the stellar population parameters studied are found. Moreover, the method of photometric stellar mass derivation affects the Hubble residual-mass relationship. For an extended sample (247 objects), including SNe Ia with SDSS host galaxy photometry only, the Hubble residual-mass relationship behaves as a sloped step function. In the high-mass regime, probed by our host spectroscopy sample, this relationship is flat. Below a stellar mass of ~2x10^10^M_{sun}_, i.e. close to the evolutionary transition mass of low-redshift galaxies, the trend changes dramatically such that lower mass galaxies possess lower luminosity SNe Ia after light-curve corrections. The sloped step function of the Hubble residual-mass relationship should be accounted for when using stellar mass as a further parameter for minimizing the Hubble residuals.
- ID:
- ivo://CDS.VizieR/J/MNRAS/434/1443
- Title:
- SN Ia inside rich galaxy clusters
- Short Name:
- J/MNRAS/434/1443
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We used the Gaussian Mixture Brightest Cluster Galaxy catalogue and Sloan Digital Sky Survey-II supernovae data with redshifts measured by the Baryon Oscillation Spectroscopic Survey to identify 48 Type Ia supernovae (SNe Ia) residing in rich galaxy clusters and compare their properties with 1015 SNe Ia in the field. Their light curves were parametrized by the SALT2 model and the significance of the observed differences was assessed by a resampling technique. To test our samples and methods, we first looked for known differences between SNe Ia residing in active and passive galaxies. We confirm that passive galaxies host SNe Ia with smaller stretch, weaker colour-luminosity relation [{beta} of 2.54(22) against 3.35(14)], and that are ~ 0.1mag more luminous after stretch and colour corrections. We show that only 0.02 percent of random samples drawn from our set of SNe Ia in active galaxies can reach these values. Reported differences in the Hubble residuals scatter could not be detected, possibly due to the exclusion of outliers. We then show that, while most field and cluster SNe Ia properties are compatible at the current level, their stretch distributions are different (~3{sigma}): besides having a higher concentration of passive galaxies than the field, the cluster's passive galaxies host SNe Ia with an average stretch even smaller than those in field passive galaxies (at 95 percent confidence). We argue that the older age of passive galaxies in clusters is responsible for this effect since, as we show, old passive galaxies host SNe Ia with smaller stretch than young passive galaxies (~4{sigma}).
- ID:
- ivo://CDS.VizieR/J/ApJ/713/1026
- Title:
- SN Ia rate at redshift <~0.3 from SDSS-II
- Short Name:
- J/ApJ/713/1026
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a measurement of the volumetric Type Ia supernova (SN Ia) rate based on data from the Sloan Digital Sky Survey II (SDSS-II) Supernova Survey. The adopted sample of supernovae (SNe) includes 516 SNe Ia at redshift z<~0.3, of which 270(52%) are spectroscopically identified as SNe Ia. The remaining 246 SNe Ia were identified through their light curves; 113 of these objects have spectroscopic redshifts from spectra of their host galaxy, and 133 have photometric redshifts estimated from the SN light curves. Based on consideration of 87 spectroscopically confirmed non-Ia SNe discovered by the SDSS-II SN Survey, we estimate that 2.04^+1.61^_-0.95_% of the photometric SNe Ia may be misidentified. The sample of SNe Ia used in this measurement represents an order of magnitude increase in the statistics for SN Ia rate measurements in the redshift range covered by the SDSS-II Supernova Survey.
- ID:
- ivo://CDS.VizieR/J/ApJ/748/L29
- Title:
- SN Ia supernovae observed by Swift/XRT
- Short Name:
- J/ApJ/748/L29
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We have considered 53 Type Ia supernovae (SNe Ia) observed by the Swift X-Ray Telescope. None of the SNe Ia are individually detected at any time or in stacked images. Using these data and assuming that the SNe Ia are a homogeneous class of objects, we have calculated upper limits to the X-ray luminosity (0.2-10 keV) and mass-loss rate of L_0.2-10_<1.7x10^38^erg/s and \dot{M}<1.1x10^-6^M_{sun}_/yr x (v_w_)/(10km/s), respectively. The results exclude massive or evolved stars as the companion objects in SN Ia progenitor systems, but allow the possibility of main sequence or small stars, along with double degenerate systems consisting of two white dwarfs, consistent with results obtained at other wavelengths (e.g., UV, radio) in other studies.
- ID:
- ivo://CDS.VizieR/J/A+A/656/A61
- Title:
- SN Ib nebular phase properties
- Short Name:
- J/A+A/656/A61
- Date:
- 22 Feb 2022
- Publisher:
- CDS
- Description:
- Following our recent work on Type II supernovae (SNe), we present a set of 1D nonlocal thermodynamic equilibrium radiative transfer calculations for nebular-phase Type Ibc SNe starting from state-of-the-art explosion models with detailed nucleosynthesis. Our grid of progenitor models is derived from He stars that were subsequently evolved under the influence of wind mass loss. These He stars, which most likely form through binary mass exchange, synthesize less oxygen than their single-star counterparts with the same zero-age main sequence (ZAMS) mass. This reduction is greater in He-star models evolved with an enhanced mass loss rate. We obtain a wide range of spectral properties at 200 d. In models from He stars with an initial mass >6M_{sun}_ the [OI] {lambda}{lambda}6300, 6364 is of comparable or greater strength than [CaII] {lambda}{lambda}7291, 7323 - the strength of [OI] {lambda}{lambda}6300, 6364 increases with He-star initial mass. In contrast, models from lower mass He stars exhibit a weak [OI] {lambda}{lambda}6300, 6364, strong [CaII] {lambda}{lambda}7291, 7323, but also strong NII lines and FeII emission below 5500{AA}. The ejecta density, modulated by the ejecta mass, the explosion energy, and clumping, has a critical impact on the gas ionization, line cooling, and the spectral properties. FeII dominates the emission below 5500{AA} and is stronger at earlier nebular epochs. It ebbs as the SN ages, while the fractional flux in [OI] {lambda}{lambda}6300, 6364 and [CaII] {lambda}{lambda}7291, 7323 increases, with a similar rate, as the ejecta recombine. Although the results depend on the adopted wind mass loss rate and pre-SN mass, we find that He-stars of 6-8M_{sun}_ initially (ZAMS mass of 23-28M_{sun}_) match adequately the properties of standard SNe Ibc. This finding agrees with the oset in progenitor masses inferred from the environments of SNe Ibc relative to SNe II. Our results for less massive He stars are more perplexing, since the predicted spectra are not seen in nature. They may be missed by current surveys or associated with Type Ibn SNe in which interaction dominates over decay power.
- 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.
