- ID:
- ivo://CDS.VizieR/J/AJ/148/13
- Title:
- Redshifts of 65 CANDELS supernovae
- Short Name:
- J/AJ/148/13
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The Cosmic Assembly Near-infrared Deep Extragalactic Legacy Survey (CANDELS) was a multi-cycle treasury program on the Hubble Space Telescope (HST) that surveyed a total area of ~0.25deg^2^ with ~900 HST orbits spread across five fields over three years. Within these survey images we discovered 65 supernovae (SNe) of all types, out to z~2.5. We classify ~24 of these as Type Ia SNe (SNe Ia) based on host galaxy redshifts and SN photometry (supplemented by grism spectroscopy of six SNe). Here we present a measurement of the volumetric SN Ia rate as a function of redshift, reaching for the first time beyond z=2 and putting new constraints on SN Ia progenitor models. Our highest redshift bin includes detections of SNe that exploded when the universe was only ~3Gyr old and near the peak of the cosmic star formation history. This gives the CANDELS high redshift sample unique leverage for evaluating the fraction of SNe Ia that explode promptly after formation (<500Myr). Combining the CANDELS rates with all available SN Ia rate measurements in the literature we find that this prompt SN Ia fraction is f_p_=0.53_stat0.10sys0.26_^+/-0.09 +/-0.10^, consistent with a delay time distribution that follows a simple t^-1^ power law for all times t>40Myr. However, mild tension is apparent between ground-based low-z surveys and space-based high-z surveys. In both CANDELS and the sister HST program CLASH (Cluster Lensing And Supernova Survey with Hubble), we find a low rate of SNe Ia at z>1. This could be a hint that prompt progenitors are in fact relatively rare, accounting for only 20% of all SN Ia explosions--though further analysis and larger samples will be needed to examine that suggestion.
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Search Results
- ID:
- ivo://CDS.VizieR/J/ApJ/742/89
- Title:
- Relations between spectra and colors of SNe Ia
- Short Name:
- J/ApJ/742/89
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- To understand how best to use observations of Type Ia supernovae (SNe Ia) to obtain precise and accurate distances, we investigate the relations between spectra of SNe Ia and their intrinsic colors. Using a sample of 1630 optical spectra of 255 SNe, based primarily on data from the CfA Supernova Program, we examine how the velocity evolution and line strengths of SiII(6355) and CaII H&K are related to the B-V color at peak brightness. We find that the maximum-light velocity of SiII6355 and CaII H&K and the maximum-light pseudo-equivalent width of SiII6355 are correlated with intrinsic color, with intrinsic color having a linear relation with the SiII6355 measurements. CaII H&K does not have a linear relation with intrinsic color, but lower-velocity SNe tend to be intrinsically bluer. Combining the spectroscopic measurements does not improve intrinsic color inference. The intrinsic color scatter is larger for higher-velocity SNe Ia - even after removing a linear trend with velocity - indicating that lower-velocity SNe Ia are more "standard crayons". Employing information derived from SN Ia spectra has the potential to improve the measurements of extragalactic distances and the cosmological properties inferred from them.
- ID:
- ivo://CDS.VizieR/J/ApJ/848/56
- Title:
- Relationships between SNe Ia and the host galaxies
- Short Name:
- J/ApJ/848/56
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We use a sample of 1338 spectroscopically confirmed and photometrically classified Type Ia supernovae (SNe Ia) sourced from Carnegie Supernova Project, Center for Astrophysics Supernova Survey, Sloan Digital Sky Survey-II, and SuperNova Legacy Survey SN samples to examine the relationships between SNe Ia and the galaxies that host them. Our results provide confirmation with improved statistical significance that SNe Ia, after standardization, are on average more luminous in massive hosts (significance >5{sigma}), and decline more rapidly in massive hosts (significance >9{sigma}) and in hosts with low specific star formation rates (significance >8{sigma}). We study the variation of these relationships with redshift and detect no evolution. We split SNe Ia into pairs of subsets that are based on the properties of the hosts and fit cosmological models to each subset. Including both systematic and statistical uncertainties, we do not find any significant shift in the best-fit cosmological parameters between the subsets. Among different SN Ia subsets, we find that SNe Ia in hosts with high specific star formation rates have the least intrinsic scatter ({sigma}_int_=0.08+/-0.01) in luminosity after standardization.
- ID:
- ivo://CDS.VizieR/J/ApJS/197/20
- Title:
- Relativistic EOS for core-collapse SN simulations
- Short Name:
- J/ApJS/197/20
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We construct the equation of state (EOS) of dense matter covering a wide range of temperature, proton fraction, and density for the use of core-collapse supernova simulations. The study is based on the relativistic mean-field (RMF) theory, which can provide an excellent description of nuclear matter and finite nuclei. The Thomas-Fermi approximation in combination with assumed nucleon distribution functions and a free energy minimization is adopted to describe the non-uniform matter, which is composed of a lattice of heavy nuclei. We treat the uniform matter and non-uniform matter consistently using the same RMF theory. We present two sets of EOS tables, namely EOS2 and EOS3. EOS2 is an update of our earlier work published in 1998 (EOS1; see 1998NuPhA.637..435S and 1998PThPh.100.1013S), where only the nucleon degree of freedom is taken into account. EOS3 includes additional contributions from {Lambda} hyperons. The effect of {Lambda} hyperons on the EOS is negligible in the low-temperature and low-density region, whereas it tends to soften the EOS at high density. In comparison with EOS1, EOS2 and EOS3 have an improved design of ranges and grids, which covers the temperature range T=0.1-10^2.6^MeV with the logarithmic grid spacing {delta}log_10_(T/[MeV])=0.04 (92 points including T=0), the proton fraction range Y_p_=0-0.65 with the linear grid spacing {Delta}Y_p_=0.01 (66 points), and the density range {rho}_B_=10^5.1^-10^16^g/cm^3^ with the logarithmic grid spacing {Delta}log_10_({rho}_B_/[g/cm^3^])=0.1 (110 points).
- ID:
- ivo://CDS.VizieR/J/A+A/437/789
- Title:
- Restframe I-band light curves of SN Ia
- Short Name:
- J/A+A/437/789
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a novel technique for fitting restframe I-band light curves on a data set of 42 type Ia supernovae (SNe Ia). Using the result of the fit, we construct a Hubble diagram with 26 SNe from the subset at 0.01<z<0.1. Adding two SNe at z~0.5 yields results consistent with a flat Lambda-dominated "concordance universe'' (Omega_M_,Omega_Lambda_)=(0.25, 0.75). For one of these, SN 2000fr, new near infrared data are presented. The high redshift supernova NIR data are also used to test for systematic effects in the use of SNe Ia as distance estimators. A flat, Lambda=0, universe where the faintness of supernovae at z~0.5 is due to grey dust homogeneously distributed in the intergalactic medium is disfavoured based on the high-z Hubble diagram using this small data-set. However, the uncertainties are large and no firm conclusion may be drawn. We explore the possibility of setting limits on intergalactic dust based on B-I and B-V colour measurements, and conclude that about 20 well measured SNe are needed to give statistically significant results. We also show that the high redshift restframe I-band data points are better fit by light curve templates that show a prominent second peak, suggesting that they are not intrinsically underluminous.
- ID:
- ivo://CDS.VizieR/J/A+A/317/423
- Title:
- Revised photometry of SNIa
- Short Name:
- J/A+A/317/423
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Re-calibrated B magnitudes and (B-V) colors for the stars of the local sequences used at Asiago in the seventies as reference for the SN photometry are given in table3. For comparison, also the Asiago original data are given. Identification charts are found in the original papers.
- ID:
- ivo://CDS.VizieR/J/ApJ/902/14
- Title:
- Revised redshifts of the Pantheon supernovae Ia
- Short Name:
- J/ApJ/902/14
- Date:
- 17 Mar 2022 14:41:40
- Publisher:
- CDS
- Description:
- Redshifts used in current cosmological supernova samples are measured using two primary techniques, one based on well-measured host galaxy spectral lines and the other based on supernova-dominated spectra. Here, we construct an updated Pantheon catalog with revised redshifts, redshift sources, and estimated uncertainties for the entire sample to investigate whether these two techniques yield consistent results. The best-fit cosmological parameters using these two measurement techniques disagree, with a supernova-only sample producing {Omega}_m_ 3.2{sigma} higher and H_0_ 2.5{sigma} lower than a hostz-only sample, and we explore several possible sources of bias that could result from using the lower-precision supernova-dominated redshifts. In a pilot study, we show that using a host redshift-only subsample will generically produce lower {Omega}_m_ and matter density {Omega}_m_h^2^ and slightly higher H_0_ than previous analysis which, for the Pantheon data set, could result in supernova and cosmic microwave background measurements agreeing on {Omega}_m_h^2^ despite tension in H_0_. To obtain rigorous results, though, the Pantheon catalog should be improved by obtaining host spectra for supernovae that have faded, and future surveys should be designed to use host galaxy redshifts rather than lower-precision methods.
- ID:
- ivo://CDS.VizieR/J/ApJ/763/L27
- Title:
- RI light curves of the type IIn SN 2009ip
- Short Name:
- J/ApJ/763/L27
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Recent observations by Mauerhan et al. (2013MNRAS.430.1801M) have shown the unprecedented transition of the previously identified luminous blue variable (LBV) and supernova (SN) impostor SN 2009ip to a real Type IIn SN explosion. We present ~100 optical R- and I-band photometric measurements of SN 2009ip obtained between UT 2012 September 23.6 and October 9.6, using 0.3-0.4m aperture telescopes from the Coral Towers Observatory in Cairns, Australia. The light curves show well-defined phases, including very rapid brightening early on (0.5mag in 6hr observed during the night of September 24), a transition to a much slower rise between September 25 and September 28, and a plateau/peak around October 7. These changes are coincident with the reported spectroscopic changes that most likely mark the start of a strong interaction between the fast SN ejecta and a dense circumstellar medium formed during the LBV eruptions observed in recent years. In the 16-day observing period, SN 2009ip brightened by 3.7mag from I=17.4mag on September 23.6 (M_I_=~-14.2) to I=13.7mag (M_I_=~-17.9) on October 9.6, radiating ~3x10^49^erg in the optical wavelength range. As of 2012 October 9.6, SN 2009ip is more luminous than most Type IIP SN and comparable to other Type IIn SN.
- ID:
- ivo://CDS.VizieR/J/MNRAS/433/2240
- Title:
- SALT2 parameters and distances for SNe
- Short Name:
- J/MNRAS/433/2240
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a cosmological analysis of the Lick Observatory Supernova Search (LOSS) Type Ia supernova (SN Ia) photometry sample introduced by Ganeshalingam et al. (2010ApJS..190..418G, Cat. J/ApJS/190/418). These supernovae (SNe) provide an effective anchor point to estimate cosmological parameters when combined with data sets at higher redshift. The data presented by Ganeshalingam et al. have been rereduced in the natural system of the Katzman Automatic Imaging Telescope (KAIT) and Nickel telescopes to minimize systematic uncertainties. We have run the light-curve-fitting software SALT2 on our natural-system light curves to measure light-curve parameters for LOSS light curves and available SN Ia data sets in the literature. We present a Hubble diagram of 586 SNe in the redshift range z=0.01-1.4 with a residual scatter of 0.176mag. Of the 226 low-z SNe Ia in our sample, 91 objects are from LOSS, including 45 without previously published distances. Assuming a flat Universe, we find that the best fit for the dark energy equation-of-state parameter w=-0.86^+0.13^_-0.16_(stat)+/-0.11(sys) from SNe alone, consistent with a cosmological constant. Our data prefer a Universe with an accelerating rate of expansion with 99.999% confidence. When looking at Hubble residuals as a function of host-galaxy morphology, we do not see evidence for a significant trend, although we find a somewhat reduced scatter in Hubble residuals from SNe residing within a projected distance <10kpc of the host-galaxy nucleus ({sigma}=0.156mag). Similar to the results of Blondin, Mandel and Kirshner and Silverman et al. (2012AJ....143..126B, Cat. J/AJ/143/126), we find that Hubble residuals do not correlate with the expansion velocity of SiII{lambda}6355 measured in optical spectra near maximum light. Our data are consistent with no presence of a local "Hubble bubble". Improvements in cosmological analyses within low-z samples can be achieved by better constraining calibration uncertainties in the zero-points of photometric systems.
260. Sample of 141 SNe Ia
- ID:
- ivo://CDS.VizieR/J/A+A/644/A176
- Title:
- Sample of 141 SNe Ia
- Short Name:
- J/A+A/644/A176
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- As part of an on-going effort to identify, understand and correct for astrophysics biases in the standardization of Type Ia supernovae (SN Ia) for cosmology, we have statistically classified a large sample of nearby SNe Ia into those that are located in predominantly younger or older environments. This classification is based on the specific star formation rate measured within a projected distance of 1kpc from each SN location (LsSFR). This is an important refinement compared to using the local star formation rate directly, as it provides a normalization for relative numbers of available SN progenitors and is more robust against extinction by dust. We find that the SNe Ia in predominantly younger environments are {DELTA}Y=0.163+/-0.029mag (5.7{sigma}) fainter than those in predominantly older environments after conventional light-curve standardization. This is the strongest standardized SN Ia brightness systematic connected to the host-galaxy environment measured to date. The well-established step in standardized brightnesses between SNe Ia in hosts with lower or higher total stellar masses is smaller, at {DELTA}M=0.119+/-0.032mag (4.5{sigma}), for the same set of SNe Ia. When fit simultaneously, the environment-age offset remains very significant, with {DELTA}Y=0.129+/-0.032mag (4.0{sigma}), while the global stellar mass step is reduced to {DELTA}M=0.064+/-0.029mag (2.2{sigma}). Thus, approximately 70% of the variance from the stellar mass step is due to an underlying dependence on environment-based progenitor age. Also, we verify that using the local star formation rate alone is not as powerful as LsSFR at sorting SNe Ia into brighter and fainter subsets. Standardization that only uses the SNe Ia in younger environments reduces the total dispersion from 0.142+/-0.008mag to 0.120+/-0.010mag. We show that as environment-ages evolve with redshift, a strong bias, especially on the measurement of the derivative of the dark energy equation of state, can develop. Fortunately, data that measure and correct for this effect using our local specific star formation rate indicator, are likely to be available for many next-generation SN Ia cosmology experiments.
