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We reanalyzed spectra that were taken as part of the SL2S lens galaxy survey with the goal to obtain the stellar velocity dispersion with a precision and accuracy sufficient for time-delay cosmography. In order to achieve this goal, we…

The time delay between multiple images of strongly lensed quasars has been used to infer the Hubble constant. The primary systematic uncertainty for time-delay cosmography is the mass-sheet transform (MST), which preserves the lensing…

Cosmology and Nongalactic Astrophysics · Physics 2025-03-20 Tian Li , Thomas E. Collett , Philip J. Marshall , Sydney Erickson , Wolfgang Enzi , Lindsay Oldham , Daniel Ballard

Time-delay cosmography of lensed quasars has achieved 2.4% precision on the measurement of the Hubble constant, $H_0$. As part of an ongoing effort to uncover and control systematic uncertainties, we investigate three potential sources: 1-…

Strong-lensing time delays enable measurement of the Hubble constant ($H_{0}$) independently of other traditional methods. The main limitation to the precision of time-delay cosmography is mass-sheet degeneracy (MSD). Some of the previous…

Strong lensing time delays can measure the Hubble constant H$_0$ independent of any other probe. Assuming commonly used forms for the radial mass density profile of the lenses, a 2\% precision has been achieved with 7 Time-Delay Cosmography…

Cosmology and Nongalactic Astrophysics · Physics 2021-05-12 Simon Birrer , Tommaso Treu

While time-delay lenses can be an independent probe of $H_0$ the estimates are degenerate with the convergence of the lens near the Einstein radius. Velocity dispersions, $\sigma$, can be used to break the degeneracy, with uncertainties…

Astrophysics of Galaxies · Physics 2026-02-05 R. Forés-Toribio , C. S. Kochanek , J. A. Muñoz

To calibrate stellar velocity dispersion measurements from optical and near-IR stellar lines, and to improve the black hole mass (MBH)- stellar velocity dispersion (sigma) relation, we measure stellar velocity dispersions based on high…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-15 Wol-Rang Kang , Jong-Hak Woo , Andreas Schulze , Dominik A. Riechers , Sang Chul Kim , Daeseong Park , Vernesa Smolcic

The observed stellar kinematics of dispersion-supported galaxies are often used to measure dynamical masses. Recently, several analytical relationships between the stellar line-of-sight velocity dispersion, the projected (2D) or deprojected…

We show that the observed upper bound on the line-of-sight velocity dispersion of the stars in an early-type galaxy, sigma<400km/s, may have a simple dynamical origin within the LCDM cosmological model, under two main hypotheses. The first…

Astrophysics · Physics 2009-11-07 Abraham Loeb , P. J. E. Peebles

We use the statistics of strong gravitational lensing from the CLASS survey to impose constraints on the velocity dispersion and density profile of elliptical galaxies. This approach differs from much recent work, where the luminosity…

Astrophysics · Physics 2009-11-07 Adam N. Davis , Dragan Huterer , Lawrence M. Krauss

Recent studies have found that the oldest and most luminous galaxies in the early Universe are surprisingly compact, having stellar masses similar to present-day elliptical galaxies but much smaller sizes. This finding has attracted…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-13 Pieter G. van Dokkum , Mariska Kriek , Marijn Franx

Time-delay cosmography with gravitationally lensed quasars plays an important role in anchoring the absolute distance scale and hence measuring the Hubble constant, $H_{0}$, independent of traditional distance ladder methodology. A current…

Cosmology and Nongalactic Astrophysics · Physics 2021-08-04 Geoff C. -F. Chen , Christopher D. Fassnacht , Sherry H. Suyu , Akın Yıldırım , Eiichiro Komatsu , Jose Luis Bernal

The time delay between the arrival of photons of multiple images of time variable sources can be used to constrain absolute distances in the Universe (Refsdal 1964), and in turn obtain a direct estimate of the Hubble constant and other…

Cosmology and Nongalactic Astrophysics · Physics 2019-08-21 Simon Birrer , Tommaso Treu

We present the decomposition of the stellar velocity ellipsoid using stellar velocity dispersions within a 40 deg wedge about the major-axis (sigma_maj), the epicycle approximation, and the asymmetric drift equation. Thus, we employ no…

We present the results of a weak gravitational lensing analysis to determine whether the stellar mass or the velocity dispersion is more closely related to the amplitude of the lensing signal around galaxies - and hence to the projected…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-12 Edo van Uitert , Henk Hoekstra , Marijn Franx , David G. Gilbank , Michael D. Gladders , H. K. C. Yee

We present new measurements of the coherent motion of galaxies based on observations of the large-scale redshift-space distortions seen in the two-dimensional two-point correlation function of Luminous Red Galaxies in Data Release Seven of…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-19 Yong-Seon Song , Cristiano G. Sabiu , Issha Kayo , Robert C. Nichol

We describe a robust technique based on the ULySS IDL code for measuring velocity dispersions of galaxies observed with the MMT's fiber-fed spectrograph, Hectospec. This procedure is applicable to all Hectospec spectra having a…

Astrophysics of Galaxies · Physics 2015-06-16 Daniel Fabricant , Igor Chilingarian , Ho Seong Hwang , Michael J. Kurtz , Margaret J. Geller

Galaxy cluster masses, rich with cosmological information, can be estimated from internal dark matter (DM) velocity dispersions, which in turn can be observationally inferred from satellite galaxy velocities. However, galaxies are biased…

Measurements of the Hubble-Lema\^{i}tre constant ($H_0$) require us to estimate the distance and recession velocity of galaxies independently. Gravitational clustering that leads to the formation of galaxies and the large scale structure…

Cosmology and Nongalactic Astrophysics · Physics 2026-04-24 Swati Gavas , J S Bagla , Nishikanta Khandai

A promising method for measuring the cosmological parameter combination fsigma_8 is to compare observed peculiar velocities with peculiar velocities predicted from a galaxy density field using perturbation theory. We use N-body simulations…

Cosmology and Nongalactic Astrophysics · Physics 2021-02-03 Amber M. Hollinger , Michael J. Hudson
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