- ID:
- ivo://CDS.VizieR/J/ApJ/677/1
- Title:
- Dimensionless coordinate distances
- Short Name:
- J/ApJ/677/1
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We extend and apply a model-independent analysis method developed earlier by Daly & Djorgovski (2003ApJ...597....9D and 2004, Cat. <J/ApJ/612/652>) to new supernova, radio galaxy, and galaxy cluster samples to study the acceleration history of the universe and the properties of the dark energy. There is good agreement between results obtained with radio galaxies and supernovae, suggesting that both distance indicators are reliable. The deceleration parameter q(z) is obtained assuming only the validity of the FRW metric, allowing for a range of values of space curvature, and independent of a gravity theory and the physical nature of the contents of the universe. We show that q_0_ is independent of space curvature, and obtain q_0_=-0.48+/-0.11. The transition redshift when q_0_=0 is z_T_=0.78^+0.08^_-0.27_ for zero space curvature, and has a weak dependence on space curvature. We find good agreement between model-independent quantities and those predicted by general relativity, indicating that GR provides a good description of the data over look-back times of ten billion years.
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Search Results
- ID:
- ivo://CDS.VizieR/J/ApJ/612/652
- Title:
- Dimensionless coordinate distances to supernovae
- Short Name:
- J/ApJ/612/652
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Understanding the nature of dark energy, which appears to drive the expansion of the universe, is one of the central problems of physical cosmology today. In an earlier paper (Daly & Djorgovski, 2003ApJ...597....9D) we proposed a novel method to determine the expansion rate E(z) and the deceleration parameter q(z) in a largely model-independent way, directly from the data on coordinate distances y(z). Here we expand this methodology to include measurements of the pressure of dark energy p(z), its normalized energy density fraction f(z), and the equation-of-state parameter w(z). We then apply this methodology to a new, combined data set of distances to supernovae and radio galaxies.
- ID:
- ivo://CDS.VizieR/J/MNRAS/444/2428
- Title:
- Disturbance levels of SNe host galaxies
- Short Name:
- J/MNRAS/444/2428
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present an analysis of the relative frequencies of different supernova (SN) types in spirals with various morphologies and in barred or unbarred galaxies. We use a well-defined and homogeneous sample of spiral host galaxies of 692 SNe from the Sloan Digital Sky Survey in different stages of galaxy-galaxy interaction and activity classes of nucleus. We propose that the underlying mechanisms shaping the number ratios of SNe types can be interpreted within the framework of interaction-induced star formation, in addition to the known relations between morphologies and stellar populations. We find a strong trend in behaviour of the N_Ia_/N_CC_ ratio depending on host morphology, such that early spirals include more Type Ia SNe. The N_Ibc_/N_II_ ratio is higher in a broad bin of early-type hosts. The N_Ia_/N_CC_ ratio is nearly constant when changing from normal, perturbed to interacting galaxies, then declines in merging galaxies, whereas it jumps to the highest value in post-merging/remnant galaxies. In contrast, the N_Ibc_/N_II_ ratio jumps to the highest value in merging galaxies and slightly declines in post-merging/remnant subsample. The interpretation is that the star formation rates and morphologies of galaxies, which are strongly affected in the final stages of interaction, have an impact on the number ratios of SNe types. The N_Ia_/N_CC_ (N_Ibc_/N_II_) ratio increases (decreases) from star-forming to active galactic nuclei (AGN) classes of galaxies. These variations are consistent with the scenario of an interaction-triggered starburst evolving into AGN during the later stages of interaction, accompanied with the change of star formation and transformation of the galaxy morphology into an earlier type.
- ID:
- ivo://CDS.VizieR/J/ApJ/854/24
- Title:
- Environmental dependence of SN Ia luminosities
- Short Name:
- J/ApJ/854/24
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- It is established that there is a dependence of the luminosity of type Ia supernovae (SNe Ia) on environment: SNe Ia in young, star-forming, metal-poor stellar populations appear fainter after light-curve shape corrections than those in older, passive, metal-rich environments. This is accounted for in cosmological studies using a global property of the SN host galaxy, typically the host galaxy stellar mass. However, recent low-redshift studies suggest that this effect manifests itself most strongly when using the local star formation rate (SFR) at the SN location, rather than the global SFR or the stellar mass of the host galaxy. At high-redshift, such local SFRs are difficult to determine; here, we show that an equivalent local correction can be made by restricting the SN Ia sample in globally star-forming host galaxies to a low-mass host galaxy subset (<=10^10^M_{sun}_). Comparing this sample of SNe Ia (in locally star-forming environments) to those in locally passive host galaxies, we find that SNe Ia in locally star-forming environments are 0.081+/0.018 mag fainter (4.5{sigma}), consistent with the result reported by Rigault+ (2013A&A...560A..66R), but our conclusion is based on a sample ~5 times larger over a wider redshift range. This is a larger difference than when splitting the SN Ia sample based on global host galaxy SFR or host galaxy stellar mass. This method can be used in ongoing and future high-redshift SN surveys, where local SN Ia environments are difficult to determine.
- ID:
- ivo://CDS.VizieR/J/ApJ/874/32
- Title:
- Environment and hosts of Type Ia supernovae
- Short Name:
- J/ApJ/874/32
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The reliability of Type Ia Supernovae (SNe Ia) may be limited by the imprint of their galactic origins. To investigate the connection between supernovae and their host characteristics, we developed an improved method to estimate the stellar population age of the host as well as the local environment around the site of the supernova. We use a Bayesian method to estimate the star formation history and mass weighted age of a supernova's environment by matching observed spectral energy distributions to a synthesized stellar population. Applying this age estimator to both the photometrically and spectroscopically classified Sloan Digital Sky Survey II supernovae (N=103), we find a 0.114+/-0.039mag "step" in the average Hubble residual at a stellar age of ~8Gyr; it is nearly twice the size of the currently popular mass step. We then apply a principal component analysis on the SALT2 parameters, host stellar mass, and local environment age. We find that a new parameter, PC1, consisting of a linear combination of stretch, host stellar mass, and local age, shows a very significant (4.7{sigma}) correlation with Hubble residuals. There is a much broader range of PC1 values found in the Hubble flow sample when compared with the Cepheid calibration galaxies. These samples have mildly statistically different average PC1 values, at ~2.5{sigma}, resulting in at most a 1.3% reduction in the evaluation of H0. Despite accounting for the highly significant trend in SN Ia Hubble residuals, there remains a 9% discrepancy between the most recent precision estimates of H0 using SN Ia and the CMB.
- ID:
- ivo://CDS.VizieR/J/A+A/507/85
- Title:
- ESO/VLT 3rd year type Ia supernova data set
- Short Name:
- J/A+A/507/85
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present 139 spectra of 124 Type Ia supernovae (SNe Ia) that were observed at the ESO/VLT during the first three years of the Canada-France-Hawai Telescope (CFHT) supernova legacy survey (SNLS). This homogeneous data set is used to test for redshift evolution of SN Ia spectra, and will be used in the SNLS 3rd year cosmological analyses. Spectra have been reduced and extracted with a dedicated pipeline that uses photometric information from deep CFHT legacy survey (CFHT-LS) reference images to trace, at sub-pixel accuracy, the position of the supernova on the spectrogram as a function of wavelength. It also separates the supernova and its host light in ~60% of cases. The identification of the supernova candidates is performed using a spectrophotometric SN Ia model.
- ID:
- ivo://CDS.VizieR/J/AJ/137/3731
- Title:
- ESSENCE high-redshift supernova
- Short Name:
- J/AJ/137/3731
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the results of spectroscopic observations from the ESSENCE high-redshift supernova (SN) survey during its first four years of operation. This sample includes spectra of all SNe Ia whose light curves were presented by Miknaitis et al. (2007, Cat. J/ApJ/666/674) and used in the cosmological analyses of Davis et al. (2007ApJ...666..716D) and Wood-Vasey et al. (2007ApJ...666..694W). The sample represents 273hr of spectroscopic observations with 6.5-10m class telescopes of objects detected and selected for spectroscopy by the ESSENCE team. We present 184 spectra of 156 objects. Combining this sample with that of Matheson et al. (2008, Cat. J/AJ/135/1598), we have a total sample of 329 spectra of 274 objects. From this, we are able to spectroscopically classify 118 Type Ia SNe.
- ID:
- ivo://CDS.VizieR/J/ApJ/666/674
- Title:
- ESSENCE supernova survey
- Short Name:
- J/ApJ/666/674
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We describe the implementation and optimization of the ESSENCE supernova survey, which we have undertaken to measure the dark energy equation-of-state parameter, w=P/({rho}c^2^). We present a method for optimizing the survey exposure times and cadence to maximize our sensitivity to w for a given fixed amount of telescope time. For our survey on the CTIO 4m telescope, measuring the luminosity distances and redshifts for supernovae at modest redshifts (z~0.5+/-0.2) is optimal for determining w. We describe the data analysis pipeline based on using reliable and robust image subtraction to find supernovae automatically and in nearly real time.
- ID:
- ivo://CDS.VizieR/J/ApJS/224/3
- Title:
- ESSENCE 6yr spectroscopic follow-up
- Short Name:
- J/ApJS/224/3
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The Equation of State: Supernovae trace Cosmic Expansion (ESSENCE) survey discovered 213 Type Ia supernovae at redshifts 0.1<z<0.81 between 2002 and 2008. We present their R- and I-band photometry, measured from images obtained using the MOSAIC II camera at the CTIO Blanco, along with rapid-response spectroscopy for each object. We use our spectroscopic follow-up observations to determine an accurate, quantitative classification, and precise redshift. Through an extensive calibration program we have improved the precision of the CTIO Blanco natural photometric system. We use several empirical metrics to measure our internal photometric consistency and our absolute calibration of the survey. We assess the effect of various potential sources of systematic bias on our measured fluxes, and estimate the dominant term in the systematic error budget from the photometric calibration on our absolute fluxes is ~1%.
- ID:
- ivo://CDS.VizieR/J/MNRAS/328/1181
- Title:
- Extragalactic supernovae
- Short Name:
- J/MNRAS/328/1181
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- In order to investigate the influence of environment on supernova (SN) production, we have performed a statistical investigation of the SNe discovered in isolated galaxies, in pairs and in groups of galaxies. 22 SNe in 18 isolated galaxies, 48 SNe in 40 galaxy members of 37 pairs and 211 SNe in 170 galaxy members of 116 groups have been selected and studied.
