Related papers: Mass Discrepancy-Acceleration Relation in Einstein…

Context. Deur (2014) and Winters et al. (2023) proposed an empirical relation between the dark to total mass ratio and ellipticity in elliptical galaxies from their observed total dynamical mass-to-light ratio data M/L = (14.1 +/-…

Exploiting the relative proximity of the nearby strong-lens galaxy SNL-1, we present a critical comparison of the mass estimates derived from independent modelling techniques. We fit triaxial orbit-superposition dynamical models to…

(Abridged) Using the number and sizes of observed gravitational lenses, I derive upper limits on the dark matter content of elliptical galaxies. Galaxies built from Cold Dark Matter (CDM) mass distributions are too concentrated to…

We study the relation between the internal structure of early-type galaxies and their environment using 70 strong gravitational lenses from the Sloan ACS Lens Survey. The Sloan database is used to determine two measures of overdensity of…

We study density cusps in the center of clusters of galaxies to reconcile X-ray mass estimates with gravitational lensing masses. For various mass density models with cusps we compute X-ray surface brightness distribution, and fit them to…

Strong gravitational lensing and stellar dynamics are independent and powerful methods to probe the total gravitational potential of galaxies, and thus, their total mass profile. However, inherent degeneracies in the individual models makes…

Aims. We provide an in-depth analysis of the COSMOS-Web ring, an Einstein ring at z=2 that we serendipitously discovered in the COSMOS-Web survey and possibly the most distant lens discovered to date. Methods. We extract the visible and NIR…

Recent studies of lensing clusters reveal that it might be fairly common for a galaxy cluster that the X-ray center has an obvious offset from its gravitational center which is measured by strong lensing. We argue that if these offsets…

It is generally thought that galaxies are embedded in dark matter halos extending well beyond their luminous matter. The existence of these galactic halos is mainly derived from the larger than expected velocities of stars and gas in the…

Observations of strong gravitational lensing, stellar kinematics, and larger-scale tracers enable accurate measures of the distribution of dark matter (DM) and baryons in massive early-type galaxies (ETGs). While such techniques have been…

A measurement by microlensing of the planetary mass function of planets with masses ranging from 5M_E to 10M_J and orbital radii from 0.5 to 10 AU was reported recently. A strategy for extending the mass range down to (1-3)M_E is proposed…

The Sloan Lens ACS (SLACS) is the best studied sample of strong lenses to date. Much of our knowledge of the SLACS lenses has been obtained by combining strong lensing with stellar kinematics constraints. However, interpreting stellar…

Gravitational microlensing constraints on non-standard compact objects are conventionally derived assuming lenses trace the dark matter halo with velocities following a Maxwell-Boltzmann distribution centered around $10^{-3}c$. However, a…

We present new mass models for the gravitational lens system B1938+666, using multi-wavelength data acquired from Keck adaptive optics (AO) and Hubble Space Telescope (HST) observations. These models are the first results from the…

The gravitational fields of two isolated ellipticals, NGC 720 and NGC 1521, have been recently measured to very large galactic radii (~100 and ~200 kpc), assuming hydrostatic balance of the hot gas enshrouding them. They afford, for the…

We report the discovery of a partial Einstein ring of radius 1.48arcsec produced by a massive (and seemingly isolated) elliptical galaxy. The spectroscopic follow-up at the VLT reveals a 2L* galaxy at z=0.986, which is lensing a…

Unveiling the true nature of Dark Matter (DM), which manifests itself only through gravity, is one of the principal quests in physics. Leading candidates for DM are weakly interacting massive particles (WIMPs) or ultralight bosons (axions),…

For 18 well-observed gravitationally lensed QSOs, we compare new non-parametric mass profiles for the lensing galaxies with stellar-population models derived from published HST photometry. The large volume of parameter space searched --…

Rich and massive clusters of galaxies at intermediate redshift are capable of magnifying and distorting the images of background galaxies. A comparison of different mass estimators among these clusters can provide useful information about…

We study the variation of the dark matter mass fraction of elliptical galaxies as a function of their luminosity, stellar mass, and size using a sample of 29,469 elliptical galaxies culled from the Sloan Digital Sky Survey. We model…