- ID:
- ivo://CDS.VizieR/J/ApJ/826/56
- Title:
- HST/WFC3 obs. of Cepheids in SN Ia host gal.
- Short Name:
- J/ApJ/826/56
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We use the Wide Field Camera 3 (WFC3) on the Hubble Space Telescope (HST) to reduce the uncertainty in the local value of the Hubble constant from 3.3% to 2.4%. The bulk of this improvement comes from new near-infrared (NIR) observations of Cepheid variables in 11 host galaxies of recent type Ia supernovae (SNe Ia), more than doubling the sample of reliable SNe Ia having a Cepheid-calibrated distance to a total of 19; these in turn leverage the magnitude-redshift relation based on ~300 SNe Ia at z<0.15. All 19 hosts as well as the megamaser system NGC 4258 have been observed with WFC3 in the optical and NIR, thus nullifying cross-instrument zeropoint errors in the relative distance estimates from Cepheids. Other noteworthy improvements include a 33% reduction in the systematic uncertainty in the maser distance to NGC 4258, a larger sample of Cepheids in the Large Magellanic Cloud (LMC), a more robust distance to the LMC based on late-type detached eclipsing binaries (DEBs), HST observations of Cepheids in M31, and new HST-based trigonometric parallaxes for Milky Way (MW) Cepheids. We consider four geometric distance calibrations of Cepheids: (i) megamasers in NGC 4258, (ii) 8 DEBs in the LMC, (iii) 15 MW Cepheids with parallaxes measured with HST/FGS, HST/WFC3 spatial scanning and/or Hipparcos, and (iv) 2 DEBs in M31. The Hubble constant from each is 72.25+/-2.51, 72.04+/-2.67, 76.18+/-2.37, and 74.50+/-3.27km/s/Mpc, respectively. Our best estimate of H_0_=73.24+/-1.74km/s/Mpc combines the anchors NGC 4258, MW, and LMC, yielding a 2.4% determination (all quoted uncertainties include fully propagated statistical and systematic components). This value is 3.4{sigma} higher than 66.93+/-0.62km/s/Mpc predicted by {Lambda}CDM with 3 neutrino flavors having a mass of 0.06eV and the new Planck data, but the discrepancy reduces to 2.1{sigma} relative to the prediction of 69.3+/-0.7km/s/Mpc based on the comparably precise combination of WMAP+ACT+SPT+BAO observations, suggesting that systematic uncertainties in CMB radiation measurements may play a role in the tension. If we take the conflict between Planck high-redshift measurements and our local determination of H_0_ at face value, one plausible explanation could involve an additional source of dark radiation in the early universe in the range of {Delta}N_eff_~0.4-1. We anticipate further significant improvements in H_0_ from upcoming parallax measurements of long-period MW Cepheids.
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Search Results
- ID:
- ivo://CDS.VizieR/J/ApJ/613/200
- Title:
- Hubble Higher z Supernova Search, HHZSS
- Short Name:
- J/ApJ/613/200
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present results from the Hubble Higher z Supernova Search, the first space-based open field survey for supernovae (SNe). In cooperation with the Great Observatories Origins Deep Survey, we have used the Hubble Space Telescope with the Advanced Camera for Surveys to cover ~300arcmin^2^ in the area of the Chandra Deep Field South and the Hubble Deep Field North on five separate search epochs (separated by ~45day intervals) to a limiting magnitude of F850LP~26. These deep observations have allowed us to discover 42 SNe in the redshift range 0.2<z<1.6. As these data span a large range in redshift, they are ideal for testing the validity of Type Ia supernova progenitor models with the distribution of expected "delay times" from progenitor star formation to Type Ia SN explosion, and the SN rates these models predict. Through a Bayesian maximum likelihood test, we determine which delay-time models best reproduce the redshift distribution of SNe Ia discovered in this survey. We find that models that require a large fraction of "prompt" (less than 2Gyr) SNe Ia poorly reproduce the observed redshift distribution and are rejected at greater than 95% confidence. We find that Gaussian models best fit the observed data for mean delay times in the range of 2-4Gyr.
- ID:
- ivo://CDS.VizieR/J/MNRAS/449/1753
- Title:
- I-band light curves of SNe II from OGLE-IV
- Short Name:
- J/MNRAS/449/1753
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We study a sample of 11 Type II supernovae (SNe) discovered by the OGLE-IV survey. All objects have well-sampled I-band light curves, and at least one spectrum. We find that two or three of the 11 SNe have a declining light curve, and spectra consistent with other SNe II-L, while the rest have plateaus that can be as short as 70 d, unlike the 100 d typically found in nearby galaxies. The OGLE SNe are also brighter, and show that magnitude-limited surveys find SNe that are different than usually found in nearby galaxies. We discuss this sample in the context of understanding Type II SNe as a class and their suggested use as standard candles.
114. IfA Deep SN rates
- ID:
- ivo://CDS.VizieR/J/ApJ/723/47
- Title:
- IfA Deep SN rates
- Short Name:
- J/ApJ/723/47
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The IfA Deep Survey uncovered ~130 thermonuclear supernova (TN SN, i.e., Type Ia) candidates at redshifts from z=0.1 out to beyond z=1. The TN SN explosion rates derived from these data have been controversial, conflicting with evidence emerging from other surveys. This work revisits the IfA Deep Survey to re-evaluate the photometric evidence. Applying the SOFT (Supernova Ontology with Fuzzy Templates) program to the light curves of all SN candidates, we derive new classification grades and redshift estimates. We find a volumetric rate for z~0.5 that is substantially smaller than the originally published values, bringing the revised IfA Deep rate into good agreement with other surveys. With our improved photometric analysis techniques, we are able to confidently extend the rate measurements to higher redshifts and we find a steadily increasing TN SN rate, with no indication of a peak out to z=1.05.
- ID:
- ivo://CDS.VizieR/J/ApJ/608/L93
- Title:
- IJ photometry of GRB 031203/SN 2003lw
- Short Name:
- J/ApJ/608/L93
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Optical and infrared monitoring of the afterglow site of gamma-ray burst GRB 031203 has revealed a brightening source embedded in the host galaxy, which we attribute to the presence of a supernova (SN) related to the GRB ("SN 2003lw"). We present details of the discovery and evolution of SN 2003lw from 0.2 to 92 days after the GRB, derived from SMARTS consortium photometry in I and J bands. GRB 031203 was an intrinsically faint GRB, and the optical light curve is dominated by the SN after the first few days. A template Type Ic light curve, constructed from SN 1998bw photometry, is consistent with the peak brightness of SN 2003lw, although the light curves are not identical. Differential astrometry reveals that the SN, and hence the GRB, occurred less than 300h_71_^-1^pc (3sigma) from the apparent galaxy center.
- ID:
- ivo://CDS.VizieR/J/ApJ/797/24
- Title:
- Imaging observations of iPTF 13ajg
- Short Name:
- J/ApJ/797/24
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present imaging and spectroscopy of a hydrogen-poor superluminous supernova (SLSN) discovered by the intermediate Palomar Transient Factory, iPTF 13ajg. At a redshift of z=0.7403, derived from narrow absorption lines, iPTF 13ajg peaked at an absolute magnitude of M_u,AB_=-22.5, one of the most luminous supernovae to date. The observed bolometric peak luminosity of iPTF 13ajg is 3.2x10^44^ erg/s, while the estimated total radiated energy is 1.3x10^51^ erg. We detect narrow absorption lines of Mg I, Mg II, and Fe II, associated with the cold interstellar medium in the host galaxy, at two different epochs with X-shooter at the Very Large Telescope. From Voigt profile fitting, we derive the column densities log N(Mg I)=11.94+/-0.06, log N(Mg II)=14.7+/-0.3, and log N(Fe II)=14.25+/-0.10. These column densities, as well as the Mg I and Mg II equivalent widths of a sample of hydrogen-poor SLSNe taken from the literature, are at the low end of those derived for gamma-ray bursts (GRBs) whose progenitors are also thought to be massive stars. This suggests that the environments of hydrogen-poor SLSNe and GRBs are different. From the nondetection of Fe II fine-structure absorption lines, we derive a lower limit on the distance between the supernova and the narrow-line absorbing gas of 50 pc. The neutral gas responsible for the absorption in iPTF 13ajg exhibits a single narrow component with a low velocity width, {Delta}V=76 km/s, indicating a low-mass host galaxy. No host galaxy emission lines are detected, leading to an upper limit on the unobscured star formation rate (SFR) of SFR_[OII]_<0.07 M_{sun}_/yr. Late-time imaging shows the iPTF 13ajg host galaxy to be faint, with g_AB_~27.0 and R_AB_>=26.0 mag, corresponding to M_B,Vega_>~-17.7 mag.
- ID:
- ivo://CDS.VizieR/J/A+A/649/A155
- Title:
- Impact of core and shell masses on SNe Ia
- Short Name:
- J/A+A/649/A155
- Date:
- 22 Feb 2022
- Publisher:
- CDS
- Description:
- Sub-Chandrasekhar yield carbon-oxygen white dwarfs with a surface helium shell have been proposed as progenitors of Type Ia supernovae (SNe Ia). If true, the resulting thermonuclear explosions should be able to account for at least some of the range of SNe Ia observables. To study this, we conducted a parameter study based on three-dimensional simulations of double detonations in carbon-oxygen white dwarfs with a helium shell, assuming different core and shell yieldes. An admixture of carbon to the shell and solar metallicity are included in the models. The hydrodynamic simulations were carried out using the Arepo code. This allowed us to follow the helium shell detonation with high numerical resolution, and this improves the reliability of predicted nucleosynthetic shell detonation yields. The addition of carbon to the shell leads to a lower production of ^56^Ni, while including solar metallicity increases the production of intermediate yield elements. The production of higher mass elements is further shifted to stable isotopes at solar metallicity. Moreover, we find different core detonation ignition mechanisms depending on the core and shell yield configuration. This has an influence on the ejecta structure. We present the bolometric light curves predicted from our explosion simulations using the Monte Carlo radiative transfer code Artis and make comparisons with bolometric SNe Ia data. The bolometric light curves of our models show a range of brightnesses, which is able to account for subluminous to normal brightness SNe Ia. We show the model bolometric width-luminosity relation compared to data for a range of model viewing angles. We find that, on average, our brighter models lie within the observed data. The ejecta asymmetries produce a wide distribution of observables, which might account for outliers in the data. However, the models overestimate the extent of this compared to data. We also find that the bolometric decline rate over 40 days, {Delta}m_40_(bol), appears systematically faster than data.
- ID:
- ivo://CDS.VizieR/J/ApJ/686/749
- Title:
- Improved cosmological constraints from SNe
- Short Name:
- J/ApJ/686/749
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a new compilation of Type Ia supernovae (SNe Ia), a new data set of low-redshift nearby-Hubble-flow SNe, and new analysis procedures to work with these heterogeneous compilations. This "Union" compilation of 414 SNe Ia, which reduces to 307 SNe after selection cuts, includes the recent large samples of SNe Ia from the Supernova Legacy Survey and ESSENCE Survey, the older data sets, as well as the recently extended data set of distant supernovae observed with the Hubble Space Telescope (HST). A single, consistent, and blind analysis procedure is used for all the various SN Ia subsamples, and a new procedure is implemented that consistently weights the heterogeneous data sets and rejects outliers. We present the latest results from this Union compilation and discuss the cosmological constraints from this new compilation and its combination with other cosmological measurements (CMB and BAO).
- ID:
- ivo://CDS.VizieR/J/ApJ/659/122
- Title:
- Improved distances to type Ia supernovae
- Short Name:
- J/ApJ/659/122
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present an updated version of the multicolor light-curve shape method to measure distances to Type Ia supernovae (SNe Ia), incorporating new procedures for K-correction and extinction corrections. We also develop a simple model to disentangle intrinsic color variations and reddening by dust and expand the method to incorporate U-band light curves and to more easily accommodate prior constraints on any of the model parameters. We apply this method to 133 nearby SNe Ia, including 95 objects in the Hubble flow (cz>=2500km/s), which give an intrinsic dispersion of less than 7% in distance. The Hubble flow sample, which is of critical importance to all cosmological uses of SNe Ia, is the largest ever presented with homogeneous distances.
- ID:
- ivo://CDS.VizieR/J/ApJ/869/167
- Title:
- Improved empirical models for Type Ia SNe
- Short Name:
- J/ApJ/869/167
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- SN Ia cosmology depends on the ability to fit and standardize observations of supernova magnitudes with an empirical model. We present here a series of new models of SN Ia spectral time series that capture a greater amount of supernova diversity than is possible with the models that are currently customary. These are entitled SuperNova Empirical MOdels (SNEMO; https://snfactory.lbl.gov/snemo). The models are constructed using spectrophotometric time series from 172 individual supernovae from the Nearby Supernova Factory, comprising more than 2000 spectra. Using the available observations, Gaussian processes are used to predict a full spectral time series for each supernova. A matrix is constructed from the spectral time series of all the supernovae, and Expectation Maximization Factor Analysis is used to calculate the principal components of the data. K-fold cross-validation then determines the selection of model parameters and accounts for color variation in the data. Based on this process, the final models are trained on supernovae that have been dereddened using the Fitzpatrick and Massa extinction relation. Three final models are presented here: SNEMO2, a two-component model for comparison with current Type Ia models; SNEMO7, a seven-component model chosen for standardizing supernova magnitudes, which results in a total dispersion of 0.100mag for a validation set of supernovae, of which 0.087mag is unexplained (a total dispersion of 0.113mag with an unexplained dispersion of 0.097mag is found for the total set of training and validation supernovae); and SNEMO15, a comprehensive 15-component model that maximizes the amount of spectral time-series behavior captured.
