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200 papers

We study the utility of a large sample of type Ia supernovae that might be observed in an imaging survey that rapidly scans a large fraction of the sky for constraining dark energy. We consider information from the traditional luminosity…

Astrophysics · Physics 2011-02-11 Andrew R. Zentner , Suman Bhattacharya

The cosmological principle assumes the isotropy of the Universe at large scales. It is a foundational assumption in the $\Lambda$CDM model, which is the current standard model of cosmology. Recent tensions give legitimacy to investigating…

We test the isotropy of the expansion of the Universe by estimating the hemispherical anisotropy of supernova type Ia (SN Ia) Hubble diagrams at low redshifts (z<0.2). We compare the best fit Hubble diagrams in pairs of hemispheres and…

Cosmology and Nongalactic Astrophysics · Physics 2022-11-25 Benedict Bahr-Kalus , Dominik J. Schwarz , Marina Seikel , Alexander Wiegand

We present a data-driven method based on long short-term memory (LSTM) neural networks to analyze spectral time series of Type Ia supernovae (SNe Ia). The dataset includes 3091 spectra from 361 individual SNe Ia. The method allows for…

High Energy Astrophysical Phenomena · Physics 2022-05-09 Lei Hu , Xingzhuo Chen , Lifan Wang

Recent released Planck data and other astronomical observations show that the universe may be anisotropic on large scales. Inspired by this, anisotropic cosmological models have been proposed. We note that the Finsler-Randers spacetime…

Cosmology and Nongalactic Astrophysics · Physics 2014-03-25 Zhe Chang , Xin Li , Hai-Nan Lin , Sai Wang

Supernova remnants (SNRs) exhibit varying degrees of anisotropy, which have been extensively modeled using numerical methods. We implement a technique to measure anisotropies in SNRs by calculating power spectra from their high-resolution…

High Energy Astrophysical Phenomena · Physics 2024-03-20 Soham Mandal , Paul C. Duffell , Abigail Polin , Dan Milisavljevic

We present an empirical model of Type Ia supernovae spectro-photometric evolution with time. The model is built using a large data set including light-curves and spectra of both nearby and distant supernovae, the latter being observed by…

In the present work, we investigate the tension in the recent Type Ia supernovae (SNIa) datasets Constitution and Union. We show that they are in tension not only with the observations of the cosmic microwave background (CMB) anisotropy and…

Cosmology and Nongalactic Astrophysics · Physics 2010-04-15 Hao Wei

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 \lesssim 0.3,…

A combined sample of 79 high and low redshift supernovae Ia (SNe) is used to set constraints on the degree of anisotropy in the Universe out to $z\simeq1$. First we derive the global most probable values of matter density $\Omega_M $, the…

Astrophysics · Physics 2015-06-24 Tsafrir S. Kolatt , Ofer Lahav

The determination of distances using time-series photometry of Type Ia supernovae (SNe Ia) relies on a ~5% empirical correction related to the properties of their host galaxies, e.g., global stellar mass. It is therefore crucial for…

Cosmology and Nongalactic Astrophysics · Physics 2026-01-28 Taylor J. Hoyt , David Rubin , Greg Aldering , Saul Perlmutter , Andrei Cuceu , Ravi Gupta

Type Ia supernovae (SNe Ia) are one of the major tools to determine the cosmological parameters. Utilizing them as distance indicators, it is possible to geometrically survey the universe. To this end, the intrinsic scatter in the…

Astrophysics · Physics 2007-05-23 F. K. Roepke , W. Hillebrandt , S. I. Blinnikov

We examine the possibility of evolution with redshift in the mean rest-frame ultraviolet (UV; <4500A) spectrum of Type Ia Supernovae (SNe Ia) sampling the redshift range 0<z<1.3. We find new evidence for a decrease with redshift in the…

Solar and Stellar Astrophysics · Physics 2011-02-11 M. Sullivan , R. S. Ellis , D. A. Howell , A. Riess , P. E. Nugent , A. Gal-Yam

We use type-Ia supernovae (SNe Ia) discovered by the SDSS-II SN Survey to search for dependencies between SN Ia properties and the projected distance to the host galaxy center, using the distance as a proxy for local galaxy properties…

The Sloan Digital Sky Survey II (SDSS-II) Supernova Survey discovered Type Ia supernovae (SNe Ia) in an almost unexplored intermediate redshift range of $0.05 < z < 0.4$ and provided densely sampled multi-color light curves for SN…

We investigate measuring the peculiar motions of galaxies up to $z=0.5$ using Type Ia supernovae (SNe Ia) from LSST, and predict the subsequent constraints on the growth rate of structure. We consider two cases. Our first is based on…

Cosmology and Nongalactic Astrophysics · Physics 2017-10-11 Cullan Howlett , Aaron S. G. Robotham , Claudia D. P. Lagos , Alex G. Kim

Ultraviolet (UV) observations of Type Ia supernovae (SNe Ia) probe the outermost layers of the explosion, and UV spectra of SNe Ia are expected to be extremely sensitive to differences in progenitor composition and the details of the…

We probe the possible anisotropy of the Universe by using the JLA compilation of type-Ia supernovae. We apply the Markov Chain Monte Carlo (MCMC) method to constrain the amplitude and direction of anisotropy in three cosmological models.…

Cosmology and Nongalactic Astrophysics · Physics 2016-01-29 Hai-Nan Lin , Sai Wang , Zhe Chang , Xin Li

More than 3000 spectroscopically confirmed Type Ia supernovae (SNe Ia) are presented in the Zwicky Transient Facility SN Ia Data Release 2 (ZTF DR2). In this paper, we detail the spectral properties of 482 SNe Ia near maximum light, up to a…