PhysBERT
Collection
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A targeted search for strongly lensed supernovae and expectations for
targeted searches in the Rubin era: Gravitationally lensed supernovae (glSNe) are of interest for time delay
cosmology and SN physics. However, glSNe detections are rare, owing to the
intrinsic rarity of SN explosions, the necessity of alignment wi... | Luminosity-dependent unification of Active Galactic Nuclei and the X-ray
Baldwin effect: The existence of an anti-correlation between the equivalent width (EW) of the
narrow core of the iron Kalpha line and the luminosity of the continuum (i.e.
the X-ray Baldwin effect) in type-I active galactic nuclei has been confi... |
Determining the Baryon Impact on the Matter Power Spectrum with Galaxy
Clusters: The redistribution of baryonic matter in massive halos through processes like
active galactic nuclei feedback and star formation leads to a suppression of
the matter power spectrum on small scales. This redistribution can be measured
emp... | Cosmography from well-localized Fast Radio Bursts: Fast Radio Bursts (FRBs) are millisecond-duration pulses occurring at
cosmological distances that have emerged as prominent cosmological probes due
to their dispersion measure (DM) evolution with redshift. In this work, we use
cosmography, a model-independent approach ... |
Gravity in the Local Universe : density and velocity fields using
CosmicFlows-4: This article publicly releases three-dimensional reconstructions of the local
Universe gravitational field below z=0.8 that were computed using the
CosmicFlows-4 catalog of 56,000 galaxy distances and its sub-sample of 1,008
type Ia supe... | Two superluminous supernovae from the early universe discovered by the
Supernova Legacy Survey: We present spectra and lightcurves of SNLS 06D4eu and SNLS 07D2bv, two
hydrogen-free superluminous supernovae discovered by the Supernova Legacy
Survey. At z = 1.588, SNLS 06D4eu is the highest redshift superluminous SN wi... |
Limits on the luminosity function of Ly-alpha emitters at z = 7.7: The Ly-alpha luminosity function (LF) of high-redshift Ly-alpha emitters
(LAEs) is one of the few observables of the re-ionization epoch accessible to
date with 8-10 m class telescopes. The evolution with redshift allows one to
constrain the evolution o... | Weak lensing power spectra for precision cosmology: Multiple-deflection,
reduced shear and lensing bias corrections: It is usually assumed that the ellipticity power spectrum measured in weak
lensing observations can be expressed as an integral over the underlying matter
power spectrum. This is true at second order i... |
Physical conditions in high-redshift GRB-DLA absorbers observed with
VLT/UVES: Implications for molecular hydrogen searches: We aim to understand the nature of the absorbing neutral gas in the galaxies
hosting high-redshift long-duration GRBs and to determine their physical
conditions. We report the detection of a si... | The Effect of a Single Supernova Explosion on the Cuspy Density Profile
of a Small-Mass Dark Matter Halo: Some observations of galaxies, and in particular dwarf galaxies, indicate a
presence of cored density profiles in apparent contradiction with cusp profiles
predicted by dark matter N-body simulations. We construc... |
Higher order clustering of Ly$α$ forest: Higher order clustering statistics of Ly$\alpha$ forest provide a unique
probe to study non-gaussianity in Intergalactic matter distribution up to high
redshifts and from large to small scales. The author presents a brief review of
his work studying the spatial clustering proper... | Third-Epoch Magellanic Cloud Proper Motions II: The Large Magellanic
Cloud Rotation Field in Three Dimensions: We present the first detailed assessment of the large-scale rotation of any
galaxy based on full three-dimensional velocity measurements. We do this for
the LMC by combining our HST average proper motion (PM... |
Universal properties in galaxies and cored Dark Matter profiles: In this paper I report the highlights of the talk: "Universal properties in
galaxies and cored Dark Matter profiles", given at: Colloquium Lectures, Ecole
Internationale d'Astrophysique Daniel Chalonge. The 14th Paris Cosmology
Colloquium 2010 "The Standa... | The Formation and Evolution of Massive Black Holes: The past 10 years have witnessed a change of perspective in the way
astrophysicists think about massive black holes (MBHs), which are now
considered to have a major role in the evolution of galaxies. This appreciation
was driven by the realization that black holes of ... |
The Evolution of Swift/BAT blazars and the origin of the MeV background: We use 3 years of data from the Swift/BAT survey to select a complete sample
of X-ray blazars above 15 keV. This sample comprises 26 Flat-Spectrum Radio
Quasars (FSRQs) and 12 BL Lac objects detected over a redshift range of
0.03<z<4.0. We use thi... | Constraining decaying dark matter with the effective field theory of
large-scale structure: I present the first constraints on decaying cold dark matter (DCDM) models
thanks to the effective field theory of large-scale structure (EFTofLSS)
applied to BOSS-DR12 data. I consider two phenomenological models of DCDM: i) ... |
Rare Events Are Nonperturbative: Primordial Black Holes From
Heavy-Tailed Distributions: In recent years it has been noted that the perturbative treatment of the
statistics of fluctuations may fail to make correct predictions for the
abundance of primordial black holes (PBHs). Moreover, it has been shown in some
expl... | Planck 2015 results. IV. Low Frequency Instrument beams and window
functions: This paper presents the characterization of the in-flight beams, the beam
window functions, and the associated uncertainties for the Planck Low Frequency
Instrument (LFI). The structure of the paper is similar to that presented in
the 2013 ... |
Probing photon decay with the Sunyaev-Zel'dovich effect: The fundamental properties of the photon have deep impact on the
astrophysical processes that involve it, like the inverse Compton scattering of
CMB photon by energetic electrons residing within galaxy cluster atmospheres,
usually referred to as the Sunyaev-Zel'd... | Halo and Subhalo Demographics with Planck Cosmological Parameters:
Bolshoi-Planck and MultiDark-Planck Simulations: We report and provide fitting functions for the abundance of dark matter
halos and subhalos as a function of mass, circular velocity, and redshift from
the new Bolshoi-Planck and MultiDark-Planck $\Lamb... |
Second-order solutions of the equilibrium statistical mechanics for
self-gravitating systems: In a previous study, we formulated a framework of the entropy-based
equilibrium statistical mechanics for self-gravitating systems. This theory is
based on the Boltzmann-Gibbs entropy and includes the generalized virial
equa... | Steady Outflows in Giant Clumps of High-z Disk Galaxies During Migration
and Growth by Accretion: We predict the evolution of giant clumps undergoing star-driven outflows in
high-z gravitationally unstable disk galaxies. We find that the mass loss is
expected to occur through a steady wind over many tens of free-fall... |
Preliminary evidence for a virial shock around the Coma galaxy cluster: Galaxy clusters, the largest gravitationally bound objects in the Universe,
are thought to grow by accreting mass from their surroundings through
large-scale virial shocks. Due to electron acceleration in such a shock, it
should appear as a $\gamma... | Minimal inflationary cosmologies and constraints on reheating: With the growing consensus on simple power law inflation models not being
favored by the PLANCK observation, dynamics for the non-standard form of the
inflaton potential gain significant interest in the recent past. In this paper,
we analyze in great detail... |
Characterizing fast radio bursts through statistical cross-correlations: Understanding the origin of fast radio bursts (FRB's) is a central unsolved
problem in astrophysics that is severely hampered by their poorly determined
distance scale. Determining the redshift distribution of FRB's appears to
require arcsecond an... | Going beyond the Kaiser redshift-space distortion formula: a full
general relativistic account of the effects and their detectability in galaxy
clustering: Kaiser redshift-space distortion formula describes well the clustering of
galaxies in redshift surveys on small scales, but there are numerous additional
terms ... |
Subhalo statistics of galactic halos: beyond the resolution limit: We study the substructure population of Milky Way (MW)-mass halos in the
$\Lambda$CDM cosmology using a novel procedure to extrapolate subhalo number
statistics beyond the resolution limit of N-body simulations. The technique
recovers the mean and the v... | Effects of Explosion Asymmetry and Viewing Angle on the Type Ia
Supernova Color and Luminosity Calibration: Phenomenological relations exist between the peak luminosity and other
observables of type Ia supernovae (SNe~Ia), that allow one to standardize their
peak luminosities. However, several issues are yet to be cl... |
Effective Theory of Dark Energy at Redshift Survey Scales: We explore the phenomenological consequences of general late-time
modifications of gravity in the quasi-static approximation, in the case where
cold dark matter is non-minimally coupled to the gravitational sector. Assuming
spectroscopic and photometric surveys... | The two-and three-point correlation functions of the polarized five-year
WMAP sky maps: We present the two- and three-point real space correlation functions of the
five-year WMAP sky maps, and compare the observed functions to simulated LCDM
concordance model ensembles. In agreement with previously published results,... |
Effect of accretion on primordial black holes in Brans-Dicke theory: We consider the effect of accretion of radiation in the early universe on
primordial black holes in Brans-Dicke theory. The rate of growth of a
primordial black hole due to accretion of radiation in Brans-Dicke theory is
considerably smaller than the ... | The photometric evolution of dissolving star clusters: II. Realistic
models. Colours and M/L ratios: Evolutionary synthesis models are the prime method to construct models of
stellar populations, and to derive physical parameters from observations. One
of the assumptions for such models so far has been the time-indep... |
Large scale structure of the Universe: A short overview is given on the development of our present paradigm of the
large scale structure of the Universe with emphasis on the role of Ya. B.
Zeldovich. Next we use the Sloan Digital Sky Survey data and show that the
distribution of phases of density waves of various scale... | Dark Matter: A Brief Review: From astronomical observations, we know that dark matter exists, makes up 23%
of the mass budget of the Universe, clusters strongly to form the load-bearing
frame of structure for galaxy formation, and hardly interacts with ordinary
matter except gravitationally. However, this information i... |
The galaxy cluster mass scale and its impact on cosmological constraints
from the cluster population: The total mass of a galaxy cluster is one of its most fundamental properties.
Together with the redshift, the mass links observation and theory, allowing us
to use the cluster population to test models of structure f... | Probing the inflationary particle content: extra spin-2 field: We study how inflationary observables associated with primordial tensor modes
are affected by coupling the minimal field content with an extra spin-2
particle during inflation. We work with a model that is ghost-free at the fully
non-linear level and show h... |
Scaling in necklaces of monopoles and semipoles: Models of symmetry breaking in the early universe can produce networks of
cosmic strings threading 't Hooft-Polyakov monopoles. In certain cases there is
a larger global symmetry group and the monopoles split into so-called
semipoles. These networks are all known as cosm... | On the Anomalous Silicate Absorption Feature of the Prototypical Seyfert
2 Galaxy NGC 1068: The first detection of the silicate absorption feature in AGNs was made at
9.7 micrometer for the prototypical Seyfert 2 galaxy NGC 1068 over 30 years
ago, indicating the presence of a large column of silicate dust in the
line... |
Under an Iron Sky: On the Entropy at the Start of the Universe: Curiously, our Universe was born in a low entropy state, with abundant free
energy to power stars and life. The form that this free energy takes is usually
thought to be gravitational: the Universe is almost perfectly smooth, and so
can produce sources of ... | Toward a New Geometric Distance to the Active Galaxy NGC 4258. III.
Final Results and the Hubble Constant: We report a new geometric maser distance estimate to the active galaxy NGC
4258. The data for the new model are maser line-of-sight velocities and sky
positions from 18 epochs of Very Long Baseline Interferometr... |
CMB lensing and primordial squeezed non-Gaussianity: Squeezed primordial non-Gaussianity can strongly constrain early-universe
physics, but it can only be observed on the CMB after it has been
gravitationally lensed. We give a new simple non-perturbative prescription for
accurately calculating the effect of lensing on ... | The Age Spread of Quiescent Galaxies with the NEWFIRM Medium-band
Survey: Identification of the Oldest Galaxies out to z~2: With a complete, mass-selected sample of quiescent galaxies from the NEWFIRM
Medium-Band Survey (NMBS), we study the stellar populations of the oldest and
most massive galaxies (>10^11 Msun) to ... |
Average Heating Rate of Hot Atmospheres in Distant Clusters by Radio
AGN: Evidence for Continuous AGN Heating: We examine atmospheric heating by radio active galactic nuclei (AGN) in
distant X-ray clusters by cross correlating clusters selected from the 400
Square Degree (400SD) X-ray Cluster survey with radio source... | Effelsberg 100-m polarimetric observations of a sample of Compact
Steep-Spectrum sources: We completed observations with the Effelsberg 100-m radio telescope to
measure the polarised emission from a complete sample of Compact Steep-Spectrum
sources. We observed the sources at four different frequencies. We complement... |
Time Delay Cosmography: Gravitational time delays, observed in strong lens systems where the variable
background source is multiply-imaged by a massive galaxy in the foreground,
provide direct measurements of cosmological distance that are very
complementary to other cosmographic probes. The success of the technique
de... | The Non-Linear Matter Power Spectrum in Warm Dark Matter Cosmologies: We investigate the non-linear evolution of the matter power spectrum by using
a large set of high-resolution N-body/hydrodynamic simulations. The linear
matter power in the initial conditions is consistently modified to accommodate
warm dark matter p... |
The fate of large-scale structure in modified gravity after GW170817 and
GRB170817A: The coincident detection of gravitational waves (GW) and a gamma-ray burst
from a merger of neutron stars has placed an extremely stringent bound on the
speed of GW. We showed previously that the presence of gravitational slip
($\eta... | Measuring the scatter of the mass-richness relation in galaxy clusters
in photometric imaging surveys by means of their correlation function: Knowledge of the scatter in the mass-observable relation is a key ingredient
for a cosmological analysis based on galaxy clusters in a photometric survey.
In this paper we aim ... |
GUT-Scale Primordial Black Holes: Mergers and Gravitational Waves: Tight constraints on the abundance of primordial black holes can be deduced
across a vast range of masses, with the exception of those light enough to
fully evaporate before nucleosynthesis. This hypothetical population is almost
entirely unconstrained,... | The Scales of Gravitational Lensing: After exactly a century since the formulation of the general theory of
relativity, the phenomenon of gravitational lensing is still an extremely
powerful method for investigating in astrophysics and cosmology. Indeed, it is
adopted to study the distribution of the stellar component ... |
Exploring Primordial Black Holes from the Multiverse with Optical
Telescopes: Primordial black holes (PBHs) are a viable candidate for dark matter if the
PBH masses are in the currently unconstrained "sublunar" mass range. We revisit
the possibility that PBHs were produced by nucleation of false vacuum bubbles
during... | The Most Massive Galaxies at 3.0<z<4.0 in the NEWFIRM Medium-Band
Survey: Properties and Improved Constraints on the Stellar Mass Function: [Abridged] We use the NEWFIRM Medium-Band Survey (NMBS) to characterize the
properties of a mass-complete sample of 14 galaxies at 3.0<z<4.0 with
M_star>2.5x10^11 Msun, and to de... |
WISE detections of known QSOs at redshifts greater than six: We present WISE All-Sky mid-infrared (IR) survey detections of 55% (17/31) of
the known QSOs at z>6 from a range of surveys: the SDSS, the CFHT-LS, FIRST,
Spitzer and UKIDSS. The WISE catalog thus provides a substantial increase in
the quantity of IR data ava... | Constraining the curvature density parameter in cosmology: The cosmic curvature density parameter has been constrained in the present
work independent of any background cosmological model. The reconstruction is
performed adopting the non-parametric Gaussian Processes (GP). The constraints
on $\Omega_{k0}$ are obtained ... |
Dark Matter Halos from the Inside Out: The balance of evidence indicates that individual galaxies and groups or
clusters of galaxies are embedded in enormous distributions of cold, weakly
interacting dark matter. These dark matter 'halos' provide the scaffolding for
all luminous structure in the universe, and their pro... | The Herschel Filament: a signature of the environmental drivers of
galaxy evolution during the assembly of massive clusters at z=0.9: We have discovered a 2.5 Mpc (projected) long filament of infrared-bright
galaxies connecting two of the three ~5x10^14 Msun clusters making up the RCS
2319+00 supercluster at z=0.9. T... |
On the luminosity distance and the epoch of acceleration: Standard cosmological models based on general relativity (GR) with dark
energy predict that the Universe underwent a transition from decelerating to
accelerating expansion at a moderate redshift $z_{acc} \sim 0.7$. Clearly, it
is of great interest to directly me... | The XMM Cluster Survey: Exploring scaling relations and completeness of
the Dark Energy Survey Year 3 redMaPPer cluster catalogue: We cross-match and compare characteristics of galaxy clusters identified in
observations from two sky surveys using two completely different techniques.
One sample is optically selected f... |
Statistics of the excursion sets in models with local primordial
non-Gaussianity: We use the statistics of regions above or below a temperature threshold
(excursion sets) to study the cosmic microwave background (CMB) anisotropy in
models with primordial non-Gaussianity of the local type. By computing the
full-sky sp... | Lensing dispersion of supernova flux: a probe of nonlinear structure
growth: The scatter in the apparent magnitude of type Ia supernovae induced by
stochastic gravitational lensing is highly dependent on the nonlinear growth of
cosmological structure. In this paper, we show that such a dependence can
potentially be e... |
Cosmological Features of Primordial Magnetic Fields: The aim of this thesis is to study the effects on the CMB anisotropy due to
primordial magnetic fields and to analyze some favorable scenarios of
magnetogenesis constrained by those signatures, including limits on the
amplitude of the fields from bounds on CMB non-Ga... | Simulations of the Galaxy Cluster CIZA J2242.8+5301 I: Thermal Model and
Shock Properties: The giant radio relic in CIZA J2242.8+5301 is likely evidence of a Mpc sized
shock in a massive merging galaxy cluster. However, the exact shock properties
are still not clearly determined. In particular, the Mach number derive... |
Local gravitational physics of the Hubble expansion: We study physical consequences of the Hubble expansion of FLRW manifold on
measurement of space, time and light propagation in the local inertial frame.
We analyse the solar system radar ranging and Doppler tracking experiments, and
time synchronization. FLRW manifol... | Field theoretic interpretations of interacting dark energy scenarios and
recent observations: Cosmological models describing the non-gravitational interaction between dark
matter and dark energy are based on some phenomenological choices of the
interaction rates between dark matter and dark energy. There is no such g... |
Constraints on dark matter-neutrino scattering from the Milky-Way
satellites and subhalo modeling for dark acoustic oscillations: The elastic scattering between dark matter (DM) and radiation can potentially
explain small-scale observations that the cold dark matter faces as a
challenge, as damping density fluctuatio... | Observational constraints on the metagalactic Ly$α$ photon
scattering rate at high redshift: The scattering of Ly$\alpha$ photons from the first radiating sources in the
Universe plays a pivotal role in 21-cm radio detections of Cosmic Dawn and the
Epoch of Reionization through the Wouthuysen-Field effect. New data f... |
Investigating the accelerated expansion of the Universe through updated
constraints on viable $f(R)$ models within the metric formalism: Modified theories of gravity encompass a class of $f(R)$-models that seek to
elucidate the observed late time accelerated expansion of the universe. In this
study, we examine a set ... | First Dark Matter Limits from the COUPP 4kg Bubble Chamber at a Deep
Underground Site: The COUPP 4 kg bubble chamber employs 4.0 kg of CF$_3$I as a WIMP scattering
target for use as a dark matter direct detection search. This thesis reports
the first experimental results from operating this bubble chamber at the deep... |
Cosmic flows in the nearby universe from Type Ia Supernovae: Peculiar velocities are one of the only probes of very large-scale mass
density fluctuations in the nearby Universe. We present new "minimal variance"
bulk flow measurements based upon the "First Amendment" compilation of 245 Type
Ia supernovae (SNe) peculiar... | Baryogenesis from Decaying Magnetic Helicity: As a result of the Standard Model chiral anomalies, baryon number is violated
in the early universe in the presence of a hypermagnetic field with varying
helicity. We investigate whether the matter / anti-matter asymmetry of the
universe can be created from the decaying hel... |
X-ray Scaling Relation in Early-Type Galaxies: Dark Matter as a Primary
Factor in Retaining Hot Gas: We have revisited the X-ray scaling relations of early type galaxies (ETG) by
investigating, for the first time, the LX,Gas - MTotal relation in a sample of
14 ETGs. In contrast to the large scatter (by a factor of 10... | High redshift cosmography: new results and implication for dark energy: The explanation of the accelerated expansion of the Universe poses one of the
most fundamental questions in physics and cosmology today. If the acceleration
is driven by some form of dark energy, one can try to constrain the parameters
using a cosm... |
Fast simulations of gas sloshing and cold front formation: We present a simplified and fast method for simulating minor mergers between
galaxy clusters. Instead of following the evolution of the dark matter halos
directly by the N-body method, we employ a rigid potential approximation for
both clusters. The simulations... | Probing light relics through cosmic dawn: We explore the prospects of upcoming 21-cm surveys of cosmic dawn
($12\lesssim \!z\lesssim\!30$) to provide cosmological information on top of
upcoming cosmic microwave background (CMB) and large-scale structure surveys,
such as CMB-S4, Simons Observatory (SO) and DESI. We focu... |
The viable f(G) gravity models via reconstruction from the observations: We reconstruct the viable f(G) gravity models from the observations and
provide the analytic solutions that well describe our numerical results. In
order to avoid unphysical challenges that occur during the numerical
reconstruction, we generalize ... | Four IRAC Sources with an Extremely Red H-[3.6] Color: Passive or Dusty
Galaxies at z>4.5?: We report detection of four IRAC sources in the GOODS-South field with an
extremely red color of H$-$[3.6]$>$4.5. The four sources are not detected in
the deep HST WFC3 H-band image with H$_{limit}$=28.3 mag. We find that only... |
Cosmology from LOFAR Two-metre Sky Survey Data Release 2:
Cross-correlation with the cosmic microwave background: We combine the LOw-Frequency ARray (LOFAR) Two-metre Sky Survey (LoTSS)
second data release (DR2) catalogue with gravitational lensing maps from the
Cosmic Microwave Background (CMB) to place constraints ... | Inverse Compton Contribution to the Star-Forming Extragalactic Gamma-Ray
Background: Fermi has resolved several star-forming galaxies, but the vast majority of
the star-forming universe is unresolved and thus contributes to the
extragalactic gamma ray background (EGB). Here, we calculate the contribution
from star-fo... |
Maximum Likelihood Random Galaxy Catalogues and Luminosity Function
Estimation: We present a new algorithm to generate a random (unclustered) version of an
magnitude limited observational galaxy redshift catalogue. It takes into
account both galaxy evolution and the perturbing effects of large scale
structure. The ke... | The structural elements of the cosmic web: In 1970 Zel'dovich published a far-reaching paper presenting a simple
equation describing the nonlinear growth of primordial density inhomogeneities.
The equation was remarkably successful in explaining the large scale structure
in the Universe that we observe: a Universe in w... |
Spectroscopic confirmation of hydrogen alpha-selected satellite galaxies: We present a spectroscopic test confirming the potential of narrow-band
optical imaging as a method for detecting star-forming satellites around nearby
galaxies. To date the efficiency of such methods, and particularly the fraction
of false detec... | Gravitational Waves from Abelian Gauge Fields and Cosmic Strings at
Preheating: Primordial gravitational waves provide a very important stochastic background
that could be detected soon with interferometric gravitational wave antennas or
indirectly via the induced patterns in the polarization anisotropies of the
cosm... |
Effective Field Theory for Inflation: This is a version of the author's Ph.D. thesis. The methods of effective
field theory are used to study generic theories of inflation with a single
inflaton field and to perform a general analysis of the associated
non-Gaussianities. We investigate the amplitudes and shapes of the ... | Recalibration of the virial factor and M-sigma relation for local active
galaxies: Determining the virial factor of the broad-line region (BLR) gas is crucial
for calibrating AGN black hole mass estimators, since the measured
line-of-sight velocity needs to be converted into the intrinsic virial
velocity. The average... |
Structure of neutron stars in R-squared gravity: The effects implied for the structure of compact objects by the modification
of General Relativity produced by the generalization of the Lagrangian density
to the form f(R)=R+\alpha R^2, where R is the Ricci curvature scalar, have been
recently explored. It seems likely ... | Constraints on dark energy equation of state parameters from cosmic
topology: Despite our present-day inability to predict the topology of the universe it
is expected that we should be able to detect it in the near future. A
nontrivial detectable topology of the space section of the universe can be
probed for all hom... |
Energy Deposition Profiles and Entropy in Galaxy Clusters: We report the results of our study of fractional entropy enhancement in the
intra-cluster medium (ICM) of the clusters from the representative XMM-Newton
cluster structure survey (REXCESS). We compare the observed entropy profile of
these clusters with that exp... | The cosmic history of the spin of dark matter haloes within the large
scale structure: We use N-body simulations to investigate the evolution of the orientation and
magnitude of dark matter halo angular momentum within the large scale structure
since z=3. We look at the evolution of the alignment of halo spins with
f... |
Impact of internal bremsstrahlung on the detection of gamma-rays from
neutralinos: We present a detailed study of the effect of internal bremsstrahlung photons
in the context of the minimal supersymmetric standard models and their impact
on gamma-ray dark matter annihilation searches. We find that although this
effec... | Observational Constraints on Early Coupled Quintessence: We investigate an Early Coupled Quintessence model where a light scalar
mediates a fifth force stronger than gravity among dark matter particles and
leads to the growth of perturbations prior to matter-radiation equality. Using
cosmological data from the $\textit... |
Filling in CMB map missing data using constrained Gaussian realizations: For analyzing maps of the cosmic microwave background sky, it is necessary to
mask out the region around the galactic equator where the parasitic foreground
emission is strongest as well as the brightest compact sources. Since many of
the analyses... | Prospective Type Ia Supernova Surveys From Dome A: Dome A, the highest plateau in Antarctica, is being developed as a site for
an astronomical observatory. The planned telescopes and instrumentation and the
unique site characteristics are conducive toward Type Ia supernova surveys for
cosmology. A self-contained search... |
Manyfield Inflation in Random Potentials: We construct models of inflation with many randomly interacting fields and
use these to study the generation of cosmological observables. We model the
potentials as multi-dimensional Gaussian random fields (GRFs) and identify
powerful algebraic simplifications that, for the fir... | A Study of Selection Methods for H alpha Emitting Galaxies at z~1.3 for
the Subaru/FMOS Galaxy Redshift Survey for Cosmology (FastSound): The efficient selection of high-redshift emission galaxies is important for
future large galaxy redshift surveys for cosmology. Here we describe the target
selection methods for th... |
Cosmological Tests of General Relativity with Future Tomographic Surveys: Future weak lensing surveys will map the evolution of matter perturbations
and gravitational potentials, yielding a new test of general relativity on
cosmic scales. They will probe the relations between matter overdensities,
local curvature, and ... | Hierarchical clustering and the BAO signature: In this contribution we present the preliminary results regarding the
non-linear BAO signal in higher-order statistics of the cosmic density field.
We use ensembles of N-body simulations to show that the non-linear evolution
changes the amplitudes of the BAO signal, but ha... |
Microlensing of Sub-parsec Massive Binary Black Holes in Lensed QSOs:
Light Curves and Size-Wavelength Relation: Sub-parsec binary massive black holes (BBHs) are long anticipated to exist in
many QSOs but remain observationally elusive. In this paper, we propose a novel
method to probe sub-parsec BBHs through microle... | Interference pattern in the collision of structures in the BEC dark
matter model: comparison with fluids: In order to explore nonlinear effects on the distribution of matter during
collisions within the Bose-Einstein condensate (BEC) dark matter model driven
by the Schr\"odinger-Poisson system of equations, we study ... |
Interpreting the Global 21-cm Signal from High Redshifts. II. Parameter
Estimation for Models of Galaxy Formation: Following our previous work, which related generic features in the
sky-averaged (global) 21-cm signal to properties of the intergalactic medium,
we now investigate the prospects for constraining a simple... | The one-loop bispectrum of galaxies in redshift space from the Effective
Field Theory of Large-Scale Structure: We derive the kernels and the Effective Field Theory of Large-Scale Structure
counterterms for the one-loop bispectrum of dark matter and of biased tracers
in real and redshift space. This requires the expa... |
Testing gravity with gravitational waves $\times$ electromagnetic probes
cross-correlations: In a General Relativistic framework, Gravitational Waves (GW) and
Electromagnetic (EM) waves are expected to respond in the same way to the
effects of matter perturbations between the emitter and the observer. A
different beh... | Horizon-Flow off-track for Inflation: Inflation can be parameterized by means of truncated flow equations. In this
"horizon-flow" setup, generic results have been obtained, such as typical
values for $r/(1-n_\mathrm{S})$. They are sometimes referred to as intrinsic
features of inflation itself. In this paper we first s... |
SNe Ia as a cosmological probe: Type Ia supernovae luminosities can be corrected to render them useful as
standard candles able to probe the expansion history of the universe. This
technique was successful applied to discover the present acceleration of the
universe. As the number of SNe Ia observed at high redshift in... | Measurements of the Rate of Type Ia Supernovae at Redshift z < ~0.3 from
the SDSS-II Supernova Survey: We present a measurement of the volumetric Type Ia supernova (SN Ia) rate
based on data from the Sloan Digital Sky Survey II (SDSS-II) Supernova Survey.
The adopted sample of supernovae (SNe) includes 516 SNe Ia at ... |
Chandra observations of dying radio sources in galaxy clusters: The dying radio sources represent a very interesting and largely unexplored
stage of the active galactic nucleus (AGN) evolution. They are considered to be
very rare, and almost all of the few known ones were found in galaxy clusters.
However, considering ... | Optimal bispectrum constraints on single-field models of inflation: We use WMAP 9-year bispectrum data to constrain the free parameters of an
'effective field theory' describing fluctuations in single-field inflation. The
Lagrangian of the theory contains a finite number of operators associated with
unknown mass scales... |
Growth of Dark Matter Perturbations during Kination: If the Universe's energy density was dominated by a fast-rolling scalar field
while the radiation bath was hot enough to thermally produce dark matter, then
dark matter with larger-than-canonical annihilation cross sections can generate
the observed dark matter relic... | Spectral Energy Distribution variation in BL Lacs and FSRQs: We present the results of our study of spectral energy distributions (SEDs)
of a sample of ten low- to intermediate-synchrotron-peaked blazars. We
investigate some of the physical parameters most likely responsible for the
observed short-term variations in bl... |
Galactic Outflows and Evolution of the Interstellar Medium: We present a model to self-consistently describe the joint evolution of
starburst galaxies and the galactic wind resulting from this evolution. We
combine the population synthesis code Starburst99 with a semi-analytical model
of galactic outflows and a model f... | Separating inner and outer contributions in gravitational lenses using
the perturbative method: This paper presents a reconstruction of the gravitational lens SL2S02176-0513
using the singular perturbative method presented in Alard 2007, MNRAS Letters,
382, 58 and Alard, C., 2008, MNRAS, 388, 375. The ability of the ... |
Cosmology of the selfaccelerating third order Galileon: In this paper we start from the original formulation of the galileon model
with the original choice for couplings to gravity. Within this framework we
find that there is still a subset of possible Lagrangians that give
selfaccelerating solutions with stable spheri... | The Future of Primordial Features with Large-Scale Structure Surveys: Primordial features are one of the most important extensions of the Standard
Model of cosmology, providing a wealth of information on the primordial
universe, ranging from discrimination between inflation and alternative
scenarios, new particle detec... |
Challenges in Constraining Gravity with Cosmic Voids: We compare void size and clustering statistics for nDGP and $f(R)$ gravity
models and GR using N-body simulations. We show how it is critical to consider
the statistics derived from mock galaxy catalogs rather than the dark matter
halos alone. Marked differences bet... | The Evolution of the Hubble Sequence: morpho-kinematics of distant
galaxies: The main objective of my thesis was to provide us, for the first time, with a
reliable view of the distant Hubble sequence, and its evolution over the past 6
Gyr. To achieve this goal, we have created a new morphological classification
metho... |
The statistical theory of dark matter flow and high order kinematic and
dynamic relations for velocity and density correlations: Statistical theory for self-gravitating collisionless dark matter flow is not
fully developed because of 1) intrinsic complexity involving constant
divergence flow on small scale and irrota... | A Technique for Foreground Subtraction in Redshifted 21 cm Observations: One of the main challenges for future 21 cm observations is to remove
foregrounds which are several orders of magnitude more intense than the HI
signal. We propose a new technique for removing foregrounds of the redshifted
21 cm observations. We c... |
Massive Primordial Black Holes in Contemporary and Young Universe (old
predictions and new data): A brief review of the recent astronomical data, indicating that the universe
is abundantly populated by heavy black holes (BH), is presented. Conventional
astrophysics and cosmology cannot explain such a high population ... | A physical understanding of how reionization suppresses accretion onto
dwarf halos: We develop and test with cosmological simulations a physically motivated
theory for how the interplay between gravity, pressure, cooling, and
self-shielding set the redshift--dependent mass scale at which halos can
accrete intergalact... |
Improved BBN Constraints on the Variation of the Gravitational Constant: Big Bang Nucleosynthesis (BBN) is very sensitive to the cosmological
expansion rate. If the gravitational constant $G$ took a different value during
the nucleosynthesis epoch than today, the primordial abundances of light
elements would be affecte... | Fisher Matrix Preloaded -- Fisher4Cast: The Fisher Matrix is the backbone of modern cosmological forecasting. We
describe the Fisher4Cast software: a general-purpose, easy-to-use, Fisher
Matrix framework. It is open source, rigorously designed and tested and
includes a Graphical User Interface (GUI) with automated LATE... |
The improved Amati correlations from Gaussian copula: In this paper, we obtain two improved Amati correlations of the Gamma-Ray
burst (GRB) data via a powerful statistical tool called copula. After
calibrating, with the low-redshift GRB data, the improved Amati correlations
based on a fiducial $\Lambda$CDM model with $... | Excursion set peaks in energy as a model for haloes: The simplest models of dark matter halo formation are based on the heuristic
assumption, motivated by spherical collapse, that virialized haloes originate
from initial regions that are maxima of the smoothed density field. Here, we
replace this notion with the dynami... |
Testing Screening Mechanisms with Mass Profiles of Galaxy Clusters: We present \textsc{MG-MAMPOSSt}, a license-free code to constrain modified
gravity models by reconstructing the mass profile of galaxy clusters with the
kinematics of the cluster's member galaxies. We describe the main features of
the code and we show ... | Self-shielding effect of a single phase liquid xenon detector for direct
dark matter search: Liquid xenon is a suitable material for a dark matter search. For future
large scale experiments, single phase detectors are attractive due to their
simple configuration and scalability. However, in order to reduce background... |
On the origin of the fundamental metallicity relation and the scatter in
galaxy scaling relations: We present a simple toy model to understand what sets the scatter in star
formation and metallicity of galaxies at fixed mass. The scatter ultimately
arises from the intrinsic scatter in the accretion rate, but may be
s... | Statistical analysis with cosmic-expansion-rate measurements and
two-point diagnostics: Direct measurements of Hubble parameters $H(z)$ are very useful for
cosmological model parameters inference. Based on them, Sahni, Shafieloo and
Starobinski introduced a two-point diagnostic $Omh^2(z_i, z_j)$ as an
interesting too... |
Cosmology with Eddington-inspired Gravity: We study the dynamics of homogeneous, isotropic universes which are governed
by the Eddington-inspired alternative theory of gravity which has a single
extra parameter, $\kappa$. Previous results showing singularity-avoiding
behaviour for $\kappa > 0$ are found to be upheld in... | Early massive clusters and the bouncing coupled dark energy: The abundance of the most massive objects in the Universe at different epochs
is a very sensitive probe of the cosmic background evolution and of the growth
history of density perturbations, and could provide a powerful tool to
distinguish between a cosmologi... |
Bayesian Cluster Finder: Clusters in the CFHTLS Archive Research Survey: The detection of galaxy clusters in present and future surveys enables
measuring mass-to-light ratios, clustering properties, galaxy cluster
abundances and therefore, constraining cosmological parameters. We present a
new technique for detecting g... | Probing Physics Beyond the Standard Model: Limits from BBN and the CMB
Independently and Combined: We present new Big Bang Nucleosynthesis (BBN) limits on the cosmic expansion
rate or relativistic energy density, quantified via the number $N_\nu$ of
equivalent neutrino species. We use the latest light element observa... |
Quantifying discordance in the 2015 Planck CMB spectrum: We examine the internal consistency of the Planck 2015 cosmic microwave
background (CMB) temperature anisotropy power spectrum. We show that tension
exists between cosmological constant cold dark matter (LCDM) model parameters
inferred from multipoles l<1000 (rou... | Vibrationally Excited HCN in the Luminous Infrared Galaxy NGC 4418: Infrared pumping and its effect on the excitation of HCN molecules can be
important when using rotational lines of HCN to probe dense molecular gas in
galaxy nuclei. We report the first extragalactic detection of (sub)millimeter
rotational lines of vib... |
Structure formation from non-Gaussian initial conditions: multivariate
biasing, statistics, and comparison with N-body simulations: We study structure formation in the presence of primordial non-Gaussianity of
the local type with parameters f_NL and g_NL. We show that the distribution of
dark-matter halos is naturall... | Primordial black hole formation from non-Gaussian curvature
perturbations: We consider several early Universe models that allow for production of large
curvature perturbations at small scales. As is well known, such perturbations
can lead to formation of primordial black holes (PBHs). We briefly review the
today's si... |
UV-extending Ghost Inflation: We present a setup that provides a partial UV-completion of the ghost
inflation model up to a scale which can be almost as high as the Planck mass.
This is achieved by coupling the inflaton to the Lorentz-violating sector
described by the Einstein-aether theory or its khronometric version.... | Stability and pulsation of the first dark stars: The first bright objects to form in the Universe might not have been
"ordinary" fusion-powered stars, but "Dark Stars" (DSs) powered by the
annihilation of dark matter (DM) in the form of Weakly Interacting Massive
Particles (WIMPs). If discovered, DSs can provide a uniq... |
Constraining the early universe with primordial black holes: In this thesis, the effect of non-Gaussianity upon the abundance of
primordial black holes (PBHs), and the implications of such an effect are
considered. It is shown that even small non-Gaussianity parameters can have a
large effect on the constraints that ca... | Deep Luminosity Functions and Colour-Magnitude Relations for Cluster
Galaxies at 0.2 < z < 0.6: We derive deep $I$ band luminosity functions and colour-magnitude diagrams
from HST imaging for eleven $0.2<z<0.6$ clusters observed at various stages of
merging, and a comparison sample of five more relaxed clusters at si... |
Testing gravity with halo density profiles observed through
gravitational lensing: We present a new test of the modified gravity endowed with the Vainshtein
mechanism with the density profile of a galaxy cluster halo observed through
gravitational lensing. A scalar degree of freedom in the galileon modified
gravity i... | The XMM Cluster Survey: Galaxy Morphologies and the Color-Magnitude
Relation in XMMXCS J2215.9-1738 at z=1.46: We present a study of the morphological fractions and color-magnitude
relation in the most distant X-ray selected galaxy cluster currently known,
XMMXCS J2215.9-1738 at z=1.46, using a combination of optical... |
Properties and use of CMB power spectrum likelihoods: Fast robust methods for calculating likelihoods from CMB observations on
small scales generally rely on approximations based on a set of power spectrum
estimators and their covariances. We investigate the optimality of these
approximation, how accurate the covarianc... | Constraints on interacting dark energy revisited: implications for the
Hubble tension: In this paper, we have revisited a class of coupled dark energy models where
dark energy interacts with dark matter via phenomenological interactions. We
included correction terms on the perturbation equations taking into account t... |
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