9.7.5 The determination of the Hubble constant H{0}

2006 ◽  
pp. 372-373
Author(s):  
G. Börner
Keyword(s):  
Hubble Constant

scholarly journals The Hubble constant from eight time-delay galaxy lenses

2020 ◽  
Vol 501 (1) ◽  
pp. 784-801 ◽  
Author(s):  
Philipp Denzel ◽  
Jonathan P Coles ◽  
Prasenjit Saha ◽  
Liliya L R Williams
Keyword(s):  
Time Delay ◽  
Hubble Constant ◽  
Free Form ◽  
Microwave Background ◽  
Form Analysis ◽  
Systematic Uncertainties ◽  
Type Ia ◽  
Modelling Strategies ◽  
Supernovae Type Ia

ABSTRACT We present a determination of the Hubble constant from the joint, free-form analysis of eight strongly, quadruply lensing systems. In the concordance cosmology, we find $H_0{} = 71.8^{+3.9}_{-3.3}\, \mathrm{km}\, \mathrm{s}^{-1}\, \mathrm{Mpc}^{-1}{}{}$ with a precision of $4.97{{\ \rm per\ cent}}$. This is in agreement with the latest measurements from supernovae Type Ia and Planck observations of the cosmic microwave background. Our precision is lower compared to these and other recent time-delay cosmography determinations, because our modelling strategies reflect the systematic uncertainties of lensing degeneracies. We furthermore are able to find reasonable lensed image reconstructions by constraining to either value of H0 from local and early Universe measurements. This leads us to conclude that current lensing constraints on H0 are not strong enough to break the ‘Hubble tension’ problem of cosmology.

scholarly journals Redshifts and Large Scale Structures

1983 ◽  
Vol 104 ◽  
pp. 159-165
Author(s):  
G. Chincarini
Keyword(s):  
Deceleration Parameter ◽  
Large Scale ◽  
Hubble Constant ◽  
Large Scale Structures ◽  
Classical Paper ◽  
Scale Structures

The effort to measure the geometry of space by experiment, that is, the determination of the Hubble Constant, Ho, and of the deceleration parameter, qo, led toward the end of the first half of the century, to the classical paper by Humason, Mayall, and Sandage (1956). Their catalogue contains 920 redshifts collected over a twenty-year period (1935–1955). Further redshifts of galaxies were measured to refine such determinations and to study the dynamics of clusters (Zwicky 1933).

scholarly journals Theoretical Light Curves for Type Ia Supernovae and Determination of the Hubble Constant

1999 ◽  
Vol 183 ◽  
pp. 68-68
Author(s):  
Koichi Iwamoto ◽  
Ken'Ichi Nomoto
Keyword(s):  
Hubble Constant ◽  
Light Curves ◽  
Type Ia Supernovae ◽  
Maximum Brightness ◽  
Decline Rate ◽  
Type Ia ◽  
Error Bars ◽  
Ia Supernovae ◽  
Distance Indicators

The large luminosity (MV ≈ −19 ∼ −20) and the homogeneity in light curves and spectra of Type Ia supernovae(SNe Ia) have led to their use as distance indicators ultimately to determine the Hubble constant (H0). However, an increasing number of the observed samples from intermediate- and high-z (z ∼ 0.1 − 1) SN Ia survey projects(Hamuy et al. 1996, Perlmutter et al. 1997) have shown that there is a significant dispersion in the maximum brightness (∼ 0.4 mag) and the brighter-slower correlation between the brightness and the postmaximum decline rate, which was first pointed out by Phillips(1993). By taking the correlation into account, Hamuy et al.(1996) gave an estimate of H0 within the error bars half as much as previous ones.

scholarly journals The Carnegie-Chicago Hubble Program. VIII. An Independent Determination of the Hubble Constant Based on the Tip of the Red Giant Branch

2019 ◽  
Vol 882 (1) ◽  
pp. 34 ◽  
Author(s):  
Wendy L. Freedman ◽  
Barry F. Madore ◽  
Dylan Hatt ◽  
Taylor J. Hoyt ◽  
In Sung Jang ◽  
...  
Keyword(s):  
Hubble Constant ◽  
Independent Determination ◽  
Red Giant

scholarly journals Red Clump Stars – Further Improved Distance Indicator

2002 ◽  
Vol 12 ◽  
pp. 688 ◽  
Author(s):  
P.M. Garnavich ◽  
K. Stanek
Keyword(s):  
Galactic Center ◽  
Hubble Constant ◽  
Large Magellanic Cloud ◽  
Solar Neighborhood ◽  
Horizontal Branch Stars ◽  
Standard Value ◽  
Distance Indicator ◽  
Red Clump ◽  
Distance Indicators

AbstractThe ideal distance indicator would be a standard candle abundant enough to provide many examples within reach of parallax measurements and sufficiently bright to be seen out to Local Group galaxies. The red clump stars closely match this description. These are the metal rich equivalent of the better known horizontal branch stars, and their brightness dispersion is only 0.2 mag (one sigma) in the Solar neighborhood. Using Hipparcos to calibrate a large, local sample, the red clump method has been used to measure accurate distances to the Galactic center (Paczyński & Stanek 1998), M31 (Stanek & Garnavich 1998), LMC (Udalski et al. 1998; Stanek et al. 1998; Udalski 1999) and some clusters in our Galaxy (e.g. 47Tuc: Kaluzny et al. 1998). As with all the distance indicators, the main worry lies in the possible systematics of the method, in particular, the brightness dependence on the stellar metallicity and age. These dependences have come under close scrutiny and, indeed, the population effects on the red clump brightness appear small and calibratable. Perhaps the most controversial result from the red clump method is the estimation of a “short” distance to the Large Magellanic Cloud (Udalski et al. 1998; Stanek, Zaritsky & Harris 1998; Udalski 2000). This distance to the LMC is shorter by 12% than the “standard” value, and has very important implications for the Cepheid distance scale and the determination of the Hubble constant.

scholarly journals The Global Hubble Constant

1990 ◽  
Vol 43 (2) ◽  
pp. 189
Author(s):  
N Visvanathan
Keyword(s):  
Large Scale ◽  
Velocity Dispersion ◽  
Hubble Constant ◽  
Virgo Cluster ◽  
A Value ◽  
Best Value ◽  
Nearby Galaxies ◽  
Distance Data ◽  
Distance Relation

A review of large-scale investigations of the determination of H is presented. The infrared period-luminosity relation of Cepheids gives distances accurate to -2% to nearby galaxies. Based on the distances of M31, MH, N300 and N2403, a DM of 31 �30 �O� 20 has been derived to the nearby Virgo cluster from the TF relation of spirals at four wavebands. Distances to more distant clusters extending up to a redshift of -10000 km S-I obtained through the CM relation of E galaxies, the TF relation of spirals and the velocity dispersion-luminosity relation of E galaxies give a value of H of 71 km S-I Mpcl when these distances are normalised to a Virgo DM of 31�30. The scatter in the redshift-distance relation of these clusters is -500 km s-I arising from the presence of unaccounted peculiar motions of individual clusters. The magnitude limited all-sky samples of galaxies also give a value of H near 70 km S-I Mpcl once the data are corrected for Malmquist bias. The best value of the global Hubble constant obtained from the redshift-distance data of Virgo and farther clusters, as well as the magnitude limited samples involving various methods of determining distances by different observers, is 73 km S-i Mpcl . Taking into account the error in the calibration of our DM of Virgo we can set a generous error of 10 to this value of H.

scholarly journals Strong gravitational lensing: relativity in action

2009 ◽  
Vol 5 (S261) ◽  
pp. 249-259
Author(s):  
Joachim Wambsganss
Keyword(s):  
Gravitational Lensing ◽  
Extrasolar Planets ◽  
Hubble Constant ◽  
Stellar Atmospheres ◽  
Gravitational Lens ◽  
Cosmological Distance Scale ◽  
Galaxy Halos ◽  
Guided Tour ◽  
Observational Science

AbstractDeflection of light by gravity was predicted by Einstein's Theory of General Relativity and observationally confirmed in 1919. In the following decades, various aspects of the gravitational lens effect were explored theoretically, among them measuring the Hubble constant from multiple images of a background source, making use of the magnifying effect as a gravitational telescope, or the possibility of a “relativistic eclipse” as a perfect test of GR. Only in 1979, gravitational lensing became an observational science when the first doubly imaged quasar was discovered. Today lensing is a booming part of astrophysics and cosmology. A whole suite of strong lensing phenomena have been investigated: multiple quasars, giant luminous arcs, Einstein rings, quasar microlensing, and galactic microlensing. The most recent lensing application is the detection of extrasolar planets. Lensing has contributed significant new results in areas as different as the cosmological distance scale, mass determination of galaxy clusters, physics of quasars, searches for dark matter in galaxy halos, structure of the Milky Way, stellar atmospheres and exoplanets. A guided tour through some of these applications will illustrate how gravitational lensing has established itself as a very useful universal astrophysical tool.

Sign in / Sign up

Export Citation Format

Share Document