Constraints on the Progenitors of Type Ia Supernovae and Implications for the Cosmological Equation of State

2001 ◽  
Vol 557 (1) ◽  
pp. 279-291 ◽  
Author(s):  
Inma Dominguez ◽  
Peter Hoflich ◽  
Oscar Straniero
Keyword(s):  
Equation Of State ◽  
Type Ia Supernovae ◽  
Cosmological Equation ◽  
Type Ia ◽  
Ia Supernovae

scholarly journals RECONSTRUCTION OF 5D COSMOLOGICAL MODELS FROM RECENT OBSERVATIONS

2007 ◽  
Vol 16 (10) ◽  
pp. 1573-1579
Author(s):  
CHENGWU ZHANG ◽  
LIXIN XU ◽  
YONGLI PING ◽  
HONGYA LIU
Keyword(s):  
Dark Matter ◽  
Dark Energy ◽  
Equation Of State ◽  
Cosmological Solution ◽  
Type Ia Supernovae ◽  
Shift Parameter ◽  
Type Ia ◽  
Ia Supernovae ◽  
Best Fit ◽  
The Universe

We use a parameterized equation of state (EOS) of dark energy to a 5D Ricci-flat cosmological solution and suppose the universe contains two major components: dark matter and dark energy. Using the recent observational datasets: the latest 182 type Ia Supernovae Gold data, the three-year WMAP CMB shift parameter and the SDSS baryon acoustic peak, we obtain the best fit values of the EOS and two major components' evolution. We find that the best fit EOS crosses -1 in the near past where z ≃ 0.07, the present best fit value of wx(0) < -1 and for this model, the universe experiences the acceleration at about z ≃ 0.5.

scholarly journals VARIABLE CHAPLYGIN GAS: CONSTRAINTS FROM CMBR ANDSNe Ia

2006 ◽  
Vol 15 (07) ◽  
pp. 1089-1098 ◽  
Author(s):  
GEETANJALI SETHI ◽  
SUSHIL K. SINGH ◽  
PRANAV KUMAR ◽  
DEEPAK JAIN ◽  
ABHA DEV
Keyword(s):  
Equation Of State ◽  
Positive Function ◽  
Chaplygin Gas ◽  
Scale Factor ◽  
Type Ia Supernovae ◽  
Data Set ◽  
Cosmological Scale ◽  
Type Ia ◽  
Ia Supernovae

We constrain the parameters of the variable Chaplygin gas model, using the location of peaks of the CMBR spectrum and the SNe Ia "gold" data set. The equation of state of the model is P = -A(a)/ρ, where A(a) = A0a-nis a positive function of the cosmological scale factor a, A0and n> being constants. The variable Chaplygin gas interpolates from the dust-dominated era to the quintessence dominated era. The model is found to be compatible with current type Ia supernovae data and the location of the first peak if the values of Ωmand n lie in the interval [0.017, 0.117] and [-1.3, 2.6], respectively.

scholarly journals Testing the isotropy of the Universe with Type Ia supernovae in a model-independent way

2017 ◽  
Vol 474 (3) ◽  
pp. 3516-3522 ◽  
Author(s):  
Yu-Yang Wang ◽  
F Y Wang
Keyword(s):  
Dark Energy ◽  
Equation Of State ◽  
Light Curve ◽  
Type Ia Supernovae ◽  
Anisotropic Universe ◽  
Preferred Direction ◽  
Type Ia ◽  
Model Independent ◽  
Ia Supernovae ◽  
The Universe

Abstract In this paper, we study an anisotropic universe model with Bianchi-I metric using Joint light-curve analysis (JLA) sample of Type Ia supernovae (SNe Ia). Because light-curve parameters of SNe Ia vary with different cosmological models and SNe Ia samples, we fit the SNe Ia light-curve parameters and cosmological parameters simultaneously employing Markov chain Monte Carlo method. Therefore, the results on the amount of deviation from isotropy of the dark energy equation of state (δ), and the level of anisotropy of the large-scale geometry (Σ0) at present, are totally model-independent. The constraints on the skewness and cosmic shear are −0.101 &lt; δ &lt; 0.071 and −0.007 &lt; Σ0 &lt; 0.008. This result is consistent with a standard isotropic universe (δ = Σ0 = 0). However, a moderate level of anisotropy in the geometry of the Universe and the equation of state of dark energy, is allowed. Besides, there is no obvious evidence for a preferred direction of anisotropic axis in this model.

scholarly journals SNe Ia as a cosmological probe

2015 ◽  
Vol 24 (14) ◽  
pp. 1530029 ◽  
Author(s):  
Xiangcun Meng ◽  
Yan Gao ◽  
Zhanwen Han
Keyword(s):  
Dark Energy ◽  
Equation Of State ◽  
High Redshift ◽  
Type Ia Supernovae ◽  
Analysis Techniques ◽  
Type Ia ◽  
History Of ◽  
Acceleration Of The Universe ◽  
Ia Supernovae ◽  
The Universe

Type Ia supernovae (SNe Ia) luminosities can be corrected in order to render them useful as standard candles that are able to probe the expansion history of the universe. This technique was successfully applied to discover the present acceleration of the universe. As the number of SNe Ia observed at high redshift increases and analysis techniques are perfected, people aim to use this technique to probe the equation-of-state of the dark energy (EOSDE). Nevertheless, the nature of SNe Ia progenitors remains controversial and concerns persist about possible evolution effects that may be larger and harder to characterize than the more obvious statistical uncertainties.

scholarly journals Progenitor Evolution and Dark Energy Time Variation from CLASH SNe Ia

2011 ◽  
Vol 7 (S281) ◽  
pp. 26-28
Author(s):  
Enikő Regős ◽  
Keyword(s):  
Dark Energy ◽  
Equation Of State ◽  
Time Variation ◽  
White Dwarf ◽  
Time Distribution ◽  
Type Ia Supernovae ◽  
Hubble Diagram ◽  
Distance Measurements ◽  
Type Ia ◽  
Ia Supernovae

AbstractThe nature and timescales behind the growth of the white dwarf toward the Chandrasekhar mass are not known. The two leading competing scenarios for Type Ia supernovae (SNe Ia) are accretion from a companion [single degenerate (SD)] or merger with another white dwarf [double degenerate (DD)]. Measurement of the SNe Ia delay time distribution could distinguish between these scenarios. Possibly both channels operate, on short (SD) and long (DD) time scales. A supernova search in parallel with our Cluster Lensing And Supernova survey with Hubble extends the Hubble diagram of SNe Ia to z > 1.5, probing progenitor evolution and testing the constancy of dark energy (DE) with time. We use HST ACS to detect SNe Ia at 1 < z < 1.5 and WFC3 to find SNe Ia at 1.5 < z < 2.5, thus providing constraints for the variation in the DE equation of state. This redshift epoch provides the unique chance to test SNe Ia distance measurements for the deleterious effects of evolution independent of our ignorance of dark energy. Our program provides the first measurement of the SNe Ia rate at z ~ 2.

scholarly journals A CONSTANT EQUATION OF STATE FOR QUINTESSENCE?

2001 ◽  
Vol 10 (02) ◽  
pp. 231-237 ◽  
Author(s):  
ELISA DI PIETRO ◽  
JACQUES DEMARET
Keyword(s):  
Equation Of State ◽  
Scalar Potential ◽  
Type Ia Supernovae ◽  
Type Ia ◽  
Ia Supernovae

Quintessence is often invoked to explain the universe's acceleration suggested by type Ia supernovae observations. The aim of this letter is to study the validity of using a constant equation of state for quintessence models. We shall show that this hypothesis strongly constraint the form of the scalar potential.

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