The dependence of Type Ia Supernovae luminosities on their host galaxies (original) (raw)
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A galaxy-driven model of type Ia supernova luminosity variations
Monthly Notices of the Royal Astronomical Society
Type Ia supernovae (SNe Ia) are used as standardizable candles to measure cosmological distances, but differences remain in their corrected luminosities which display a magnitude step as a function of host galaxy properties such as stellar mass and rest-frame U−R colour. Identifying the cause of these steps is key to cosmological analyses and provides insight into SN physics. Here we investigate the effects of SN progenitor ages on their light-curve properties using a galaxy-based forward model that we compare to the Dark Energy Survey 5-yr SN Ia sample. We trace SN Ia progenitors through time and draw their light-curve width parameters from a bimodal distribution according to their age. We find that an intrinsic luminosity difference between SNe of different ages cannot explain the observed trend between step size and SN colour. The data split by stellar mass are better reproduced by following recent work implementing a step in total-to-selective dust extinction ratio (RV) between ...
Hubble Residuals of Nearby Type Ia Supernovae are Correlated with Host Galaxy Masses
Astrophysical Journal, 2010
From Sloan Digital Sky Survey u'g'r'i'z' imaging, we estimate the stellar masses of the host galaxies of 70 low redshift SN Ia (0.015 < z < 0.08) from the hosts' absolute luminosities and mass-to-light ratios. These nearby SN were discovered largely by searches targeting luminous galaxies, and we find that their host galaxies are substantially more massive than the hosts of SN discovered by the flux-limited Supernova Legacy Survey. Testing four separate light curve fitters, we detect ~2.5{\sigma} correlations of Hubble residuals with both host galaxy size and stellar mass, such that SN Ia occurring in physically larger, more massive hosts are ~10% brighter after light curve correction. The Hubble residual is the deviation of the inferred distance modulus to the SN, calculated from its apparent luminosity and light curve properties, away from the expected value at the SN redshift. Marginalizing over linear trends in Hubble residuals with light curve parameters shows that the correlations cannot be attributed to a light curve-dependent calibration error. Combining 180 higher-redshift ESSENCE, SNLS, and HigherZ SN with 30 nearby SN whose host masses are less than 10^10.8 solar masses in a cosmology fit yields 1+w=0.22 +0.152/-0.143, while a combination where the 30 nearby SN instead have host masses greater than 10^10.8 solar masses yields 1+w=-0.03 +0.217/-0.108. Progenitor metallicity, stellar population age, and dust extinction correlate with galaxy mass and may be responsible for these systematic effects. Host galaxy measurements will yield improved distances to SN Ia.
The Cosmic Evolution of the Galaxy Luminosity Density
The Astrophysical Journal, 2003
We reconstruct the history of the cosmic star formation in the universe by means of detailed chemical evolution models for galaxies of different morphological types. We consider a picture of coeval, noninteracting evolving galaxies where ellipticals experience intense and rapid starbursts within the first Gyr after their formation, and spirals and irregulars continue to form stars at lower rates up to the present time. Such models allow one to follow in detail the evolution of the metallicity of the gas out of which the stars are formed. We normalize the galaxy population to the B band luminosity function observed in the local Universe and study the redshift evolution of the luminosity densities in the B, U, I and K bands calculating galaxy colors and evolutionary corrections by means of a detailed synthetic stellar population model. Our predictions indicate that the decline of the galaxy luminosity density between redshift 1 and 0 observed in the U, B and I bands is caused mainly by star-forming spiral galaxies which slowly exhaust their gas reservoirs. Elliptical galaxies have dominated the total luminosity density in all optical bands at early epochs, when all their stars formed by means of rapid and very intense star-bursts. Irregular galaxies bring a negligible contribution to the total luminosity density in any band at any time. We study the cosmic missing metal crisis and conclude that it could be even more serious than what has been assessed by previous authors, if the bulk of the metals were produced in dust-obscured starbursts associated with the early spheroid formation. The most plausible site for the missing metals could be the warm gas in galaxy groups and proto-clusters, in which the metals could have been ejected through galactic winds following intense starbursts. Finally, we predict the evolution of the cosmic star formation and supernova II and Ia rates and obtain the best fit to the observations assuming a Salpeter IMF. All our results indicate that the bulk of the stellar mass in most galaxies was already in place at early epochs and we predict the existence of a peak in the global SFR at high redshift due to ellipticals.
The Astrophysical Journal, 2006
We show that Type Ia supernovae (SNe Ia) are formed within both very young and old stellar populations, with observed rates that depend on the stellar mass and mean star-formation rates (SFRs) of their host galaxies. Models where the SN Ia rate depends solely on host galaxy stellar mass are ruled out with >99% confidence. Our analysis is based on 100 spectroscopically-confirmed SNe Ia, plus 24 photometrically-classified events, all from the Supernova Legacy Survey (SNLS) and distributed over 0.2<z<0.75. Using multi-band photometry, we estimate stellar masses and SFRs for the SN Ia host galaxies by fitting their broad-band spectral energy distributions with the galaxy spectral synthesis code, PEGASE.2. We show that the SN Ia rate per unit mass is proportional to the specific SFR of the parent galaxies -more vigorously star-forming galaxies host more SNe Ia per unit stellar mass, broadly equivalent to the trend of increasing SN Ia rate in later-type galaxies seen in the local universe. Following earlier suggestions for a simple "two-component" model approximating the SN Ia rate, we find bivariate linear dependencies of the SN Ia rate on both the stellar masses and the mean SFRs of the host systems. We find that the SN Ia rate can be well represented as the sum of 5.3 ± 1.1 × 10 −14 SNe per year per unit stellar mass, and 3.9 ± 0.7 × 10 −4 SNe per year per M ⊙ yr −1 of star formation.
The Astrophysical Journal, 2020
We present optical and near-infrared (ugriY JH) photometry of host galaxies of Type Ia supernovae (SN Ia) observed by the Carnegie Supernova Project-I. We determine host galaxy stellar masses and, for the first time, study their correlation with SN Ia standardized luminosity across optical and nearinfrared (uBgV riY JH) bands. In the individual bands, we find that SNe Ia are more luminous in more massive hosts with luminosity offsets ranging between −0.07±0.03 mag to −0.15±0.04 mag after lightcurve standardization. The slope of the SN Ia Hubble residual-host mass relation is negative across all uBgV riY JH bands with values ranging between −0.036±0.025 mag/dex to −0.097±0.027 mag/deximplying that SNe Ia in more massive galaxies are brighter than expected. The near-constant observed correlations across optical and near-infrared bands indicate that dust may not play a significant role in the observed luminosity offset-host mass correlation. We measure projected separations between SNe Ia and their host centers, and find that SNe Ia that explode beyond a projected 10 kpc have a 30% to 50% reduction of the dispersion in Hubble residuals across all bands-making them a more uniform subset of SNe Ia. Dust in host galaxies, peculiar velocities of nearby SN Ia, or a combination of both may drive this result as the color excesses of SNe Ia beyond 10 kpc are found to be generally lower than those interior, but there is also a diminishing trend of the dispersion as we exclude nearby events. We do not find that SN Ia average luminosity varies significantly when they are grouped in various host morphological types. Host galaxy data from this work will be useful, in conjunction with future high-redshift samples, in constraining cosmological parameters.
The Astrophysical Journal, 2012
Using data from the Sloan Digital Sky Supernova Survey-II (SDSS-II SN Survey), 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 broad-band photometry and redshifts we use the PÉGASE.2 spectral energy distributions (SEDs) to estimate host galaxy stellar masses and recent star-formation rates. We find that the rate of SNe Ia per unit stellar mass is significantly higher (by a factor of ∼ 30) in highly star-forming galaxies compared to passive galaxies. When parameterizing the SN Ia rate (SNR Ia) based on host galaxy properties, we find that the rate of SNe Ia in passive galaxies is not linearly proportional to the stellar mass, instead a SNR Ia ∝ M 0.68 is favored. However, such a parameterization does not describe the observed SN Ia rate in star-forming galaxies. The SN Ia rate in star-forming galaxies is well fit by SNR Ia = 1.05 ± 0.16 × 10 −10 M 0.68±0.01 + 1.01 ± 0.09 × 10 −3Ṁ 1.00±0.05 (statistical errors only), where M is the host galaxy mass (in M ⊙) andṀ is the star-formation rate (in M ⊙ yr −1). These results are insensitive to the selection criteria used, redshift limit considered and the inclusion of non-spectroscopically confirmed SNe Ia. We also show there is a dependence between the distribution of the MLCS light-curve decline rate parameter, ∆, and host galaxy type. Passive galaxies host less luminous SNe Ia than seen in moderately and highly star-forming galaxies, although a population of luminous SNe is observed in passive galaxies, contradicting previous assertions that these SNe Ia are only observed in younger stellar systems. The MLCS extinction parameter, A V , is similar in passive and moderately star-forming galaxies, but we find indications that it is smaller, on average, in highly star-forming galaxies. We confirm this result using the SALT2 light-curve fitter.
Supernovae in Early‐Type Galaxies: Directly Connecting Age and Metallicity with Type Ia Luminosity
The Astrophysical Journal, 2008
We have obtained optical spectra of 29 early-type (E/S0) galaxies that hosted type Ia supernovae (SNe Ia). We have measured absorption-line strengths and compared them to a grid of models to extract the relations between the supernova properties and the luminosity-weighted age/composition of the host galaxies. Such a direct measurement is a marked improvement over existing analyses which tend to rely on general correlations between the properties of stellar populations and morphology. Our galaxy sample ranges over a factor of ten in iron abundance and shows both old and young dominant population ages. The same analysis was applied to a large number of early-type field galaxies selected from the SDSS spectroscopic survey. We find no difference in the age and abundance distributions between the field galaxies and the SN Ia host galaxies. We do find a strong correlation suggesting that SNe Ia in galaxies whose populations have a characteristic age greater than 5 Gyr are ∼ 1 mag fainter at V max than those
Measuring Cosmological Parameters with Type Ia Supernovae in redMaGiC Galaxies
The Astrophysical Journal
Current and future cosmological analyses with Type Ia supernovae (SNe Ia) face three critical challenges: (i) measuring the redshifts from the SNe or their host galaxies; (ii) classifying the SNe without spectra; and (iii) accounting for correlations between the properties of SNe Ia and their host galaxies. We present here a novel approach that addresses each of these challenges. In the context of the Dark Energy Survey (DES), we analyze an SN Ia sample with host galaxies in the redMaGiC galaxy catalog, a selection of luminous red galaxies. redMaGiC photo-z estimates are expected to be accurate to σ Δz/(1+z) ∼ 0.02. The DES-5YR photometrically classified SN Ia sample contains approximately 1600 SNe, and 125 of these SNe are in redMaGiC galaxies. We demonstrate that redMaGiC galaxies almost exclusively host SNe Ia, reducing concerns relating to classification uncertainties. With this subsample, we find similar Hubble scatter (to within ∼0.01 mag) using photometric redshifts in place ...
Improved Dark Energy Constraints from ~100 New CfA Supernova Type Ia Light Curves
Astrophysical Journal, 2009
We combine the CfA3 supernova Type Ia (SN Ia) sample with samples from the literature to calculate improved constraints on the dark energy equation of state parameter, w. The CfA3 sample is added to the Union set of Kowalski et al. (2008) to form the Constitution set and, combined with a BAO prior, produces 1+w=0.013 +0.066/-0.068 (0.11 syst), consistent with the cosmological constant. The CfA3 addition makes the cosmologically-useful sample of nearby SN Ia between 2.6 and 2.9 times larger than before, reducing the statistical uncertainty to the point where systematics play the largest role. We use four light curve fitters to test for systematic differences: SALT, SALT2, MLCS2k2 (R_V=3.1), and MLCS2k2 (R_V=1.7). SALT produces high-redshift Hubble residuals with systematic trends versus color and larger scatter than MLCS2k2. MLCS2k2 overestimates the intrinsic luminosity of SN Ia with 0.7 < Delta < 1.2. MLCS2k2 with R_V=3.1 overestimates host-galaxy extinction while R_V=1.7 does not. Our investigation is consistent with no Hubble bubble. We also find that, after light-curve correction, SN Ia in Scd/Sd/Irr hosts are intrinsically fainter than those in E/S0 hosts by 2 sigma, suggesting that they may come from different populations. We also find that SN Ia in Scd/Sd/Irr hosts have low scatter (0.1 mag) and reddening. Current systematic errors can be reduced by improving SN Ia photometric accuracy, by including the CfA3 sample to retrain light-curve fitters, by combining optical SN Ia photometry with near-infrared photometry to understand host-galaxy extinction, and by determining if different environments give rise to different intrinsic SN Ia luminosity after correction for light-curve shape and color.
The Effect of Host Galaxies on Type Ia Supernovae in the SDSS-II Supernova Survey
The Astrophysical …, 2010
We present an analysis of the host galaxy dependencies of Type Ia Supernovae (SNe Ia) from the full three year sample of the SDSS-II Supernova Survey. We re-discover, to high significance, the strong correlation between host galaxy type and the width of the observed SN light curve, i.e., fainter, quickly declining SNe Ia favor passive host galaxies, while brighter, slowly declining Ia's favor star-forming galaxies. We also find evidence (at between 2 to 3σ) that SNe Ia are ≃ 0.1±0.04 magnitudes brighter in passive host galaxies, than in star-forming hosts, after the SN Ia light curves have been standardized using the light curve shape and color variations: This difference in brightness is present in both the SALT2 and MCLS2k2 light curve fitting methodologies. We see evidence for differences in the SN Ia color relationship between passive and star-forming host galaxies, e.g., for the MLCS2k2 technique, we see that SNe Ia in passive hosts favor a dust law of R V = 1.0 ± 0.2, while SNe Ia in star-forming hosts require R V = 1.8 +0.2 −0.4 . The significance of these trends depends on the range of SN colors considered. We demonstrate that these effects can be parameterized using the stellar mass of the host galaxy (with a confidence of > 4σ) and including this extra parameter provides a better statistical fit to our data. Our results suggest that future cosmological analyses of SN Ia samples should include host galaxy information.