scholarly journals Supernova Type Ia Luminosities, Their Dependence on Second Parameters, and the Value ofH0

2000 ◽  
Vol 540 (2) ◽  
pp. 634-651 ◽  
Author(s):  
B. R. Parodi ◽  
A. Saha ◽  
A. Sandage ◽  
G. A. Tammann
Keyword(s):  
Type Ia ◽  
Supernova Type Ia

scholarly journals Constraining a double component dark energy model using supernova type Ia data

2007 ◽  
Vol 367 (6) ◽  
pp. 423-430 ◽  
Author(s):  
J.C. Fabris ◽  
S.V.B. Gonçalves ◽  
Fabrício Casarejos ◽  
Jaime F. Villas da Rocha
Keyword(s):  
Dark Energy ◽  
Dark Energy Model ◽  
Energy Model ◽  
Type Ia ◽  
Supernova Type Ia

scholarly journals A PRELIMINARY ANALYSIS OF THE ENERGY TRANSFER BETWEEN THE DARK SECTORS OF THE UNIVERSE

2009 ◽  
Vol 24 (21) ◽  
pp. 1689-1698 ◽  
Author(s):  
JIA ZHOU ◽  
BIN WANG ◽  
DIEGO PAVÓN ◽  
ELCIO ABDALLA
Keyword(s):  
Dark Matter ◽  
Dark Energy ◽  
Preliminary Analysis ◽  
Irreversible Processes ◽  
Sterile Neutrinos ◽  
Thermodynamics Of Irreversible Processes ◽  
Independent Estimate ◽  
Type Ia ◽  
Supernova Type Ia ◽  
The Universe

We study the mutual interaction between the dark sectors (dark matter and dark energy) of the Universe by resorting to the extended thermodynamics of irreversible processes and constrain the former with supernova type Ia data. As a by-product, the present dark matter temperature results are not extremely small and can meet the independent estimate of the temperature of the gas of sterile neutrinos.

scholarly journals Measurements of $$H_0$$ and reconstruction of the dark energy properties from a model-independent joint analysis

2021 ◽  
Vol 81 (2) ◽  
Author(s):  
Alexander Bonilla ◽  
Suresh Kumar ◽  
Rafael C. Nunes
Keyword(s):  
Dark Energy ◽  
Sound Speed ◽  
Hubble Constant ◽  
State Parameter ◽  
Independent Method ◽  
Joint Analysis ◽  
Acoustic Oscillations ◽  
Type Ia ◽  
Model Independent ◽  
Supernova Type Ia

AbstractGaussian processes (GP) provide an elegant and model-independent method for extracting cosmological information from the observational data. In this work, we employ GP to perform a joint analysis by using the geometrical cosmological probes such as Supernova Type Ia (SN), Cosmic chronometers (CC), Baryon Acoustic Oscillations (BAO), and the H0LiCOW lenses sample to constrain the Hubble constant $$H_0$$ H 0 , and reconstruct some properties of dark energy (DE), viz., the equation of state parameter w, the sound speed of DE perturbations $$c^2_s$$ c s 2 , and the ratio of DE density evolution $$X = \rho _\mathrm{de}/\rho _\mathrm{de,0}$$ X = ρ de / ρ de , 0 . From the joint analysis SN+CC+BAO+H0LiCOW, we find that $$H_0$$ H 0 is constrained at 1.1% precision with $$H_0 = 73.78 \pm 0.84\ \hbox {km}\ \hbox {s}^{-1}\,\hbox {Mpc}^{-1}$$ H 0 = 73.78 ± 0.84 km s - 1 Mpc - 1 , which is in agreement with SH0ES and H0LiCOW estimates, but in $$\sim 6.2 \sigma $$ ∼ 6.2 σ tension with the current CMB measurements of $$H_0$$ H 0 . With regard to the DE parameters, we find $$c^2_s < 0$$ c s 2 < 0 at $$\sim 2 \sigma $$ ∼ 2 σ at high z, and the possibility of X to become negative for $$z > 1.5$$ z > 1.5 . We compare our results with the ones obtained in the literature, and discuss the consequences of our main results on the DE theoretical framework.

HALOS OF MODIFIED GRAVITY

2008 ◽  
Vol 17 (13n14) ◽  
pp. 2555-2562 ◽  
Author(s):  
KIRILL KRASNOV ◽  
YURI SHTANOV
Keyword(s):  
General Relativity ◽  
Dark Matter ◽  
Cosmological Constant ◽  
Modified Gravity ◽  
Alternative Explanation ◽  
Gravitational Mass ◽  
Spherically Symmetric ◽  
Simple Modification ◽  
Type Ia ◽  
Supernova Type Ia

We describe how a certain simple modification of general relativity, in which the local cosmological constant is allowed to depend on the space–time curvature, predicts the existence of halos of modified gravity surrounding spherically symmetric objects. We show that the gravitational mass of an object weighed together with its halo can be much larger than its gravitational mass as seen from inside the halo. This effect could provide an alternative explanation of the dark-matter phenomenon in galaxies. In this case, the local cosmological constant in the solar system must be some six orders of magnitude larger than its cosmic value obtained in the supernova type Ia experiments. This is well within the current experimental bounds, but may be directly observable in future high-precision experiments.

The quantum gravitational field theory and the domains of its fix points for inflationary or low-redshift universe

2015 ◽  
Vol 30 (28n29) ◽  
pp. 1545003 ◽  
Author(s):  
She-Sheng Xue
Keyword(s):  
Field Theory ◽  
Fixed Point ◽  
Gravitational Field ◽  
Correlation Length ◽  
Quantitative Description ◽  
Invariant Region ◽  
Cosmological Observations ◽  
Type Ia ◽  
Supernova Type Ia ◽  
Scaling Invariant

We study a quantum field theory for the Einstein–Cartan gravity and the domain of its ultraviolet unstable (stable) fixed point [Formula: see text] [Formula: see text] of running gravitational constant [Formula: see text], where inflationary (low-redshift) universe can be realized as the basic space-time cutoff [Formula: see text] approaching to the Planck length [Formula: see text]. Because the fundamental operators of quantum gravitational field theory are dimension-2 area operators, the cosmological constant is inversely proportional to the squared correlation length [Formula: see text]. The correlation length [Formula: see text] characterizes an infrared size of a causally correlate patch of the universe. The quantitative description of low-redshift universe in the scaling-invariant region of fixed point [Formula: see text] is given, and its deviation from the [Formula: see text]CDM can be examined by recent cosmological observations, such as supernova Type Ia.

scholarly journals IMPROVED DARK ENERGY CONSTRAINTS FROM ∼100 NEW CfA SUPERNOVA TYPE Ia LIGHT CURVES

2009 ◽  
Vol 700 (2) ◽  
pp. 1097-1140 ◽  
Author(s):  
Malcolm Hicken ◽  
W. Michael Wood-Vasey ◽  
Stephane Blondin ◽  
Peter Challis ◽  
Saurabh Jha ◽  
...  
Keyword(s):  
Dark Energy ◽  
Light Curves ◽  
Energy Constraints ◽  
Type Ia ◽  
Supernova Type Ia

scholarly journals An exploration of heterogeneity in supernova type Ia samples

2017 ◽  
Vol 2017 (06) ◽  
pp. 034-034 ◽  
Author(s):  
Ujjaini Alam ◽  
Jeremie Lasue
Keyword(s):  
Type Ia ◽  
Supernova Type Ia

scholarly journals An in-depth reanalysis of the alleged type Ia supernova progenitor Henize 2−428

2020 ◽  
Vol 638 ◽  
pp. A93 ◽  
Author(s):  
N. Reindl ◽  
V. Schaffenroth ◽  
M. M. Miller Bertolami ◽  
S. Geier ◽  
N. L. Finch ◽  
...  
Keyword(s):  
Light Curve ◽  
Radial Velocity ◽  
Zero Point ◽  
Asymptotic Giant Branch ◽  
Additional Absorption ◽  
Wavelength Calibration ◽  
Asymptotic Giant Branch Star ◽  
Diffuse Interstellar Bands ◽  
Type Ia ◽  
Supernova Type Ia

Context. The nucleus of the planetary nebula Hen 2-428 is a short orbital-period (4.2 h), double-lined spectroscopic binary, whose status as a potential supernova type Ia progenitor has raised some controversy in the literature. Aims. With the aim of resolving this debate, we carried out an in-depth reanalysis of the system. Methods. Our approach combines a refined wavelength calibration, thorough line-identifications, improved radial-velocity measurements, non-LTE spectral modeling, as well as multi-band light-curve fitting. Our results are then discussed in view of state-of-the-art stellar evolutionary models. Results. Besides systematic zero-point shifts in the wavelength calibration of the OSIRIS spectra which were also used in the previous analysis of the system, we found that the spectra are contaminated with diffuse interstellar bands. Our Voigt-profile radial velocity fitting method, which considers the additional absorption of these diffuse interstellar bands, reveals significantly lower masses (M1 = 0.66 ± 0.11 M⊙ and M2 = 0.42 ± 0.07 M⊙) than previously reported and a mass ratio that is clearly below unity. Our spectral and light curve analyses lead to consistent results, however, we find higher effective temperatures and smaller radii than previously reported. Moreover, we find that the red-excess that was reported before to prove to be a mere artifact of an outdated reddening law that was applied. Conclusions. Our work shows that blends of He II λ 5412 Å with diffuse interstellar bands have led to an overestimation of the previously reported dynamical masses of Hen 2−428. The merging event of Hen 2−428 will not be recognised as a supernova type Ia, but most likely leads to the formation of a H-deficient star. We suggest that the system was formed via a first stable mass transfer episode, followed by common envelope evolution, and it is now composed of a post-early asymptotic giant branch star and a reheated He-core white dwarf.

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