Related papers: Constraints On Duty Cycles Of Quasars At Z $\sim$ …
By comparing the results of numerical microlensing simulations to the observed long-term variability of quasars, strong upper limits on the cosmological density of compact objects in the mass range 0.01 to 0.0001 solar masses may be…
Since reionization prevents star formation in most halos below 3 x 10^9 solar masses, dwarf galaxies only populate a fraction of existing dark matter halos. We use hydrodynamic cosmological simulations of the Local Group to study the…
We present deep MUSE observations of five quasars within the first Gyr of the Universe ($z\gtrsim6$), four of which display extended Ly$\alpha$ halos. After PSF-subtraction, we reveal halos surrounding two quasars for the first time, as…
Strong lensing provides a powerful means of investigating the nature of dark matter as it probes dark matter structure on sub-galactic scales. We present an extension of a forward modeling framework that uses flux ratios from quadruply…
Recent studies of luminous infrared-selected active galactic nuclei (AGN) suggest that the reddest, most obscured objects display a higher angular clustering amplitude, and thus reside in higher-mass dark matter halos. This is a direct…
We have undertaken deep optical imaging observations of three 6.2<z<6.5 quasar fields in the i' and z' filters. These data are used to search for foreground galaxies which are gravitationally lensing the quasars and distant galaxies…
We consider the possibility that the dark matter in the halos of galaxies may be in the form of clusters of \macho s within which are embedded cold, dense gas clouds. Microlensing experiments have found evidence that the Galactic halo…
We explore the lowest mass limit that can be placed on the halo mass function in CDM using 28 strong gravitational lenses. For this purpose, we study an extreme model in which the halo mass function and mass-concentration relation follow…
On large scales galaxies and their halos are usually assumed to trace the dark matter with a constant bias and dark matter is assumed to trace the linear density field. We test these assumption using several large N-body simulations with…
We explore the kinematics of 27 z~6 quasar host galaxies observed in [CII]-158 micron ([CII]) emission with the Atacama Large Millimeter/sub-millimeter Array at a resolution of ~0.25''. We find that nine of the galaxies show disturbed [CII]…
We investigate clustering properties of quasars using a new version of our semi-analytic model of galaxy and quasar formation with state-of-the-art cosmological N-body simulations. In this study, we assume that a major merger of galaxies…
We have used a combination of high resolution cosmological N-body simulations and semi-analytic modelling of galaxy formation to investigate the processes that determine the spatial distribution of galaxies in cold dark matter (CDM) models.…
Cosmological hydrodynamic simulations predict the physical state of baryons in the circumgalactic medium (CGM), which can be directly tested via quasar absorption line observations. We use high resolution "zoom-in" simulations of 21…
ALMA [CII] line and continuum observations of five redshift z>6 quasars are presented. This sample was selected to probe lower black hole mass quasars than most previous studies. We find a wide dispersion in properties with CFHQS…
The concentrations of the cuspy dark matter halos predicted by simulations of cold dark matter are related to the cosmology in which the halos form. Observational constraints on halo concentration therefore map into constraints on…
This work aims at studying the $M_{BH}-M_{dyn}$ relation of a sample of $2<z<7$ quasars by constraining their host galaxy masses through full kinematical modeling of the cold gas kinematics, thus avoiding all possible biases and effects…
Quasars are galaxies hosting accreting supermassive black holes; due to their brightness, they are unique probes of the early universe. To date, only few quasars have been reported at $z > 6.5$ ($<$800 Myr after the Big Bang). In this work,…
Large-scale outflows are believed to be an important mechanism in the evolution of galaxies. We can determine the impact of these outflows by studying either current galaxy outflows and their effect in the galaxy or by studying the effect…
We jointly constrain the luminosity function (LF) and black hole mass function (BHMF) of broad-line quasars with forward Bayesian modeling in the quasar mass-luminosity plane, based on a homogeneous sample of ~ 58,000 SDSS DR7 quasars at z…
We revisit constraints on dark matter that is charged under a $U(1)$ gauge group in the dark sector, decoupled from Standard Model forces. We find that the strongest constraints in the literature are subject to a number of mitigating…