Related papers: Missing Mass in Collisional Debris from Galaxies
Dwarf spheroidal galaxies provide well-known challenges to the standard cold and collisionless dark matter scenario: The too-big-to-fail problem, namely the mismatch between the observed mass enclosed within the half-light radius of dwarf…
Stars and gas in galaxies, hot intracluster medium, and intergalactic photo-ionized gas make up at most half of the baryons that are expected to be present in the universe. The majority of baryons are still missing and are expected to be…
We describe the model-independent mechanism by which dark matter and dark matter structures heavier than $\sim 8\times 10^{11}$ GeV form binary pairs in the early Universe that spin down and merge both in the present and throughout the…
We report, for the first time, the detection of a sample of quenched and isolated dwarf galaxies (with 8.9 $<$ log(M$_{\rm \star}$/M$_{\rm \odot}$) $<$ 9.5) in the least dense regions of the cosmic web, including voids, filaments, and…
We present the results of N-body simulations of the accretion of high-density dwarf galaxies by low-density giant galaxies. Both galaxies contain power-law central density cusps and point masses representing supermassive black holes; the…
[Abridged...] We investigate the process of galaxy formation as can be observed in the only currently forming galaxies -- the so-called Tidal Dwarf Galaxies, hereafter TDGs -- through observations of the molecular gas detected via its CO…
A large number of faint galaxies, born less than a billion years after the big bang, have recently been discovered. The fluctuations in the distribution of these galaxies contributed to a scatter in the ionization fraction of cosmic…
We investigate the possibility that the observed rotation of galaxies can be accounted for by invoking a massive baryonic disc with no need for non-baryonic dark matter or a massive halo. There are 5 primary reasons for suggesting this: 1.…
Drexler dark matter is an alternate approach to dark matter that assumes that highly relativistic protons trapped in the halo of the galaxies could account for the missing mass. We look at various energetics involved in such a scenario such…
The spatial distributions of luminous and dark matter in massive early-type galaxies reflect the formation processes which shaped these systems. This article reviews the predictions of cosmological simulations for the dark and baryonic…
The nature of the dark matter in the Universe is one of the outstanding questions in astrophysics. In this talk, I address possible stellar baryonic contributions to the 50-90% of our Galaxy that is made of unknown dark matter. First I show…
The flatness of the rotation curve inside spiral galaxies is interpreted as the imprint of a halo of invisible matter. Using the deepest observations of distant galaxies, we have investigated how large disks could have been formed.…
The evidence is that the mass of the universe is dominated by an exotic nonbaryonic form of matter largely draped around the galaxies. It approximates an initially low pressure gas of particles that interact only with gravity, but we know…
The observed rotation curves of dark matter-dominated dwarf galaxies indicate low density cores, contrary to the predictions of CDM models. A possible solution of this problem involves stellar feedback. A strong baryonic wind driven by…
The relation between galaxies and dark matter halos is of vital importance for evaluating theoretical predictions of structure formation and galaxy formation physics. We show that the widely used method of abundance matching based on dark…
Observations of debris disks, the products of the collisional evolution of rocky planetesimals, can be used to trace planetary activity across a wide range of stellar types. The most common end points of stellar evolution are no exception…
The ubiquitous presence of dark matter in the universe is today a central tenet in modern cosmology and astrophysics. Ranging from the smallest galaxies to the observable universe, the evidence for dark matter is compelling in dwarfs,…
Using the deepest and the most complete set of observations of distant galaxies, we investigate how extended disks could have formed. Observations include spatially-resolved kinematics, detailed morphologies and photometry from UV to…
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…
Pseudo-Dirac Dark Matter is a viable type of dark matter which originates from a new Dirac fermion whose two Weyl states get slightly split in mass by a small Majorana term. The decay of the heavier to the lighter state naturally occurs…