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The Galaxy Cluster Merger Catalog: An Online Repository of Mock Observations from Simulated Galaxy Cluster Mergers: We present the "Galaxy Cluster Merger Catalog." This catalog provides an extensive suite of mock observations and related data for N-body and hydrodynamical simulations of galaxy cluster mergers and clu...
Observational Constraints on Interacting Dark Matter Model Without Dark Energy: The interacting dark matter (IDM) scenario allows for the acceleration of the Universe without Dark Energy. We constrain the IDM model by using the newly revised observational data including $H(z)$ data and Union2 SNe Ia via the Markov ch...
The Gaseous Environment of High-z Galaxies: Precision Measurements of Neutral Hydrogen in the Circumgalactic Medium of z ~ 2-3 Galaxies in the Keck Baryonic Structure Survey: We present results from the Keck Baryonic Structure Survey (KBSS), a unique spectroscopic survey designed to explore the connection between g...
First Cosmology Results using Type Ia Supernovae from the Dark Energy Survey: The Effect of Host Galaxy Properties on Supernova Luminosity: We present improved photometric measurements for the host galaxies of 206 spectroscopically confirmed type Ia supernovae discovered by the Dark Energy Survey Supernova Program (D...
Contiguous redshift parameterizations of the growth index: The growth rate of matter perturbations can be used to distinguish between different gravity theories and to distinguish between dark energy and modified gravity at cosmological scales as an explanation to the observed cosmic acceleration. We suggest here param...
KiDS+2dFLenS+GAMA: Testing the cosmological model with the $E_{\rm G}$ statistic: We present a new measurement of $E_{\rm G}$, which combines measurements of weak gravitational lensing, real-space galaxy clustering and redshift space distortions. This statistic was proposed as a consistency test of General Relativity...
Galaxy bias renormalization group: The effective field theory of large-scale structure allows for a consistent perturbative bias expansion of the rest-frame galaxy density field. In this work, we present a systematic approach to renormalize galaxy bias and stochastic parameters using a finite cutoff scale $\Lambda$. We...
Evolution of Splashback Boundaries and Gaseous Outskirts: Insights from Mergers of Self-similar Galaxy Clusters: A self-similar spherical collapse model predicts a dark matter (DM) splashback and accretion shock in the outskirts of galaxy clusters while misses a key ingredient of structure formation - processes assoc...
Astrophysical searches for a hidden-photon signal in the radio regime: Common extensions of the Standard Model of particle physics predict the existence of a "hidden" sector that comprises particles with a vanishing or very weak coupling to particles of the Standard Model (visible sector). For very light (m < 10^-14 eV...
Investigate the interaction between dark matter and dark energy: In this paper we investigate the interaction between dark matter and dark energy by considering two different interacting scenarios, i.e. the cases of constant interaction function and variable interaction function. By fitting the current observational da...
Constraining primordial non-Gaussianity via a multitracer technique with surveys by Euclid and Square Kilometre Array: We forecast future constraints on local-type primordial non-Gaussianity parameter $f_{\rm NL}$ with a photometric galaxy survey by Euclid, a continuum galaxy survey by Square Kilometre Array (SKA), a...
CosmoMIA: Cosmic Web-based redshift space halo distribution: Modern galaxy surveys demand extensive survey volumes and resolutions surpassing current dark matter-only simulations' capabilities. To address this, many methods employ effective bias models on the dark matter field to approximate object counts on a grid. Ho...
Dust polarization spectral dependence from Planck HFI data. Turning point on CMB polarization foregrounds modelling: The search for the primordial B-modes of the cosmic microwave background (CMB) relies on the separation from the brighter foreground dust signal. In this context, the characterisation of the spectral e...
Eliminating the optical depth nuisance from the CMB with 21 cm cosmology: Amongst standard model parameters that are constrained by cosmic microwave background (CMB) observations, the optical depth $\tau$ stands out as a nuisance parameter. While $\tau$ provides some crude limits on reionization, it also degrades const...
Imprint of massive neutrinos on Persistent Homology of large-scale structure: Exploiting the Persistent Homology technique and an associated complementary representation which enables us to construct a synergistic pipeline for different topological features quantified by Betti curves in reducing the degeneracy betwee...
Near-IR search for lensed supernovae behind galaxy clusters: I. Observations and transient detection efficiency: Massive galaxy clusters at intermediate redshift can magnify the flux of distant background sources by several magnitudes and we exploit this effect to search for lensed distant supernovae that may otherwi...
Resolving multiple supermassive black hole binaries with pulsar timing arrays II: genetic algorithm implementation: Pulsar timing arrays (PTAs) might detect gravitational waves (GWs) from massive black hole (MBH) binaries within this decade. The signal is expected to be an incoherent superposition of several nearly-m...
A Non-Parametric Estimate of Mass 'Scoured' in Galaxy Cores: We present a simple estimate of the mass 'deficits' in cored spheroids, as a function of galaxy mass and radius within the galaxy. Previous attempts to measure such deficits depended on fitting some functional form to the profile at large radii and extrapolat...
Simulations for 21 cm radiation lensing at EoR redshifts: We introduce simulations aimed at assessing how well weak gravitational lensing of 21cm radiation from the Epoch of Reionization ($z \sim 8$) can be measured by an SKA-like radio telescope. A simulation pipeline has been implemented to study the performance of l...
On the Transverse-Traceless Projection in Lattice Simulations of Gravitational Wave Production: It has recently been pointed out that the usual procedure employed in order to obtain the transverse-traceless (TT) part of metric perturbations in lattice simulations was inconsistent with the fact that those fields live ...
Bulges Of Nearby Galaxies With Spitzer: The Growth Of Pseudobulges In Disk Galaxies And Its Connection To Outer Disks: We study star formation rates (SFR) and stellar masses in bulges of nearby disk galaxies, using SFRs and stellar masses derived from Spitzer and GALEX data. At present day SFR the median pseudobulge ...
Constraining $M_ν$ with the Bispectrum I: Breaking Parameter Degeneracies: Massive neutrinos suppress the growth of structure below their free-streaming scale and leave an imprint on large-scale structure. Measuring this imprint allows us to constrain the sum of neutrino masses, $M_\nu$, a key parameter in particle p...
Downsizing of galaxies vs upsizing of dark-halos in a Lambda-CDM cosmology: The mass assembly of a whole population of sub-Milky Way galaxies is studied by means of hydrodynamical simulations within the $\Lambda$-CDM cosmology. Our results show that while dark halos assemble hierarchically, in stellar mass this trend...
Science with the TianQin Observatory: Preliminary Results on Stochastic Gravitational-Wave Background: In this work, we study the prospect of detecting the stochastic gravitational-wave background with the TianQin Observatory. We consider sources of both astrophysical-origin and cosmological-origin, including stellar...
Calcium-rich Gap Transients: Solving the Calcium Conundrum in the Intracluster Medium: X-ray measurements suggest the abundance of Calcium in the intracluster medium is higher than can be explained using favored models for core-collapse and Type Ia supernovae alone. We investigate whether the Calcium conundrum in the...
Discovery of the correspondence between intra-cluster radio emission and a high pressure region detected through the Sunyaev-Zel'dovich effect: We analyzed new 237 MHz and 614 MHz GMRT data of the most X-ray luminous galaxy cluster, RX J1347-1145. Our radio results are compared with the MUSTANG 90 GHz Sunyaev-Zel'dov...
Testing (modified) gravity with 3D and tomographic cosmic shear: Cosmic shear is one of the primary probes to test gravity with current and future surveys. There are two main techniques to analyse a cosmic shear survey; a tomographic method, where correlations between the lensing signal in different redshift bins are u...
Dust emission and star formation in Stephan's Quintet: We analyse a comprehensive set of MIR/FIR observations of Stephan's Quintet (SQ), taken with the Spitzer Space Observatory. Our study reveals the presence of a luminous (L_{IR}\approx 4.6x10^43 erg/s) and extended component of infrared dust emission, not connected ...
X-ray Constraints on the Lyman-Alpha Escape Fraction: We have coadded X-ray flux of all known Lyman Alpha Emitters (LAEs) in the 4 Msec Chandra Deep Field South (CDF-S) region, to place sensitive upper limits on the average unobscured star-formation rate (SFR_X) in these galaxies. A very small fraction of Lyman-Alpha g...
Large Eddy Simulations in Astrophysics: In this review, the methodology of large eddy simulations (LES) is introduced and applications in astrophysics are discussed. As theoretical framework, the scale decomposition of the dynamical equations for neutral fluids by means of spatial filtering is explained. For cosmologic...
Constraints on the Cosmological Coupling of Black Holes from the Globular Cluster NGC 3201: Globular clusters are among the oldest stellar populations in the Milky Way; consequently, they also host some of the oldest known stellar-mass black holes, providing insight into black hole formation and evolution in the earl...
Investigating the relationship between cosmic curvature and dark energy models with the latest supernova sample: We investigate the relationship between the cosmic curvature and the model of dark energy (hereafter DE) with the recent Type Ia supernovae (hereafter SNe Ia) data, i.e., the Pantheon sample including 1048...
Limits on primordial magnetic fields from direct detection experiments of gravitational wave background: Primordial magnetic fields (PMFs) can source gravitational wave background (GWB). In this paper, we investigate the possible constraints on small-scale PMF considering the ongoing and forthcoming direct detection ...
Gravitational lensing detection of an extremely dense environment around a galaxy cluster: Galaxy clusters form at the highest density nodes of the cosmic web. The clustering of massive halos is enhanced relative to the general mass distribution and matter beyond the virial region is strongly correlated to the halo m...
Statistical challenges in weak lensing cosmology: Cosmological weak lensing is the powerful probe of cosmology. Here we address one of the most fundamental, statistical questions inherent in weak lensing cosmology: whether or not we can recover the initial Gaussian information content of large-scale structure by combin...
Bose-Einstein-condensed scalar field dark matter and the gravitational wave background from inflation: new cosmological constraints and its detectability by LIGO: We consider an alternative cold dark matter candidate, ultralight bosons ($m>10^{-22}$eV) described by a complex scalar field (SFDM) with global U(1) sym...
Primordial Black Hole Scenario for the Gravitational-Wave Event GW150914: We point out that the gravitational-wave event GW150914 observed by the LIGO detectors can be explained by the coalescence of primordial black holes (PBHs). It is found that the expected PBH merger rate would exceed the rate estimated by the LIGO...
On the abundance of primordial bound states of superheavy magnetic monopoles: It has been suggested that superheavy charged particles might have been born in primordial bound pairs at the end of cosmic inflation. Such pairs have been proposed as a source of ultra-high energy cosmic rays (UHECR). We show that primordi...
Spherical Collapse and the Halo Model in Braneworld Gravity: We present a detailed study of the collapse of a spherical perturbation in DGP braneworld gravity for the purpose of modeling simulation results for the halo mass function, bias and matter power spectrum. The presence of evolving modifications to the gravitat...
On the evolution of the molecular gas fraction of star forming galaxies: We present IRAM Plateau de Bure interferometric detections of CO(1-0) emission from a 24um-selected sample of star-forming galaxies at z=0.4. The galaxies have PAH 7.7um-derived star formation rates of SFR~30-60 M_Sun/yr and stellar masses M*~10^{...
Upper End IMF Variations Deduced from HI-Selected Galaxies: Much of our understanding of modern astrophysics rest on the notion that the Initial Mass Function (IMF) is universal. Our observations of a sample of HI-selected galaxies in the light of H-alpha and the far-ultraviolet (FUV) challenge this result. The flux ra...
Deconstructing blazars: A different scheme for jet kinematics in flat-spectrum AGN: Recent VLBI studies of the morphology and kinematics of individual BL Lac objects (S5 1803+784, PKS 0735+178, etc.) have revealed a new paradigm for the pc-scale jet kinematics of these sources. Unlike the apparent superluminal outwar...
Constraints on Lorentz Invariance Violation with gamma-ray bursts via a Markov Chain Monte Carlo approach: In quantum theory of gravity, we expect the Lorentz Invariance Violation (LIV) and the modification of the dispersion relation between energy and momentum for photons. The effect of the energy-dependent velocity...
Effects of Non-Circular Motions on Azimuthal Color Gradients: Assuming that density waves trigger star formation, and that young stars preserve the velocity components of the molecular gas where they are born, we analyze the effects that non-circular gas orbits have on color gradients across spiral arms. We try two app...
CMB Constraints on Principal Components of the Inflaton Potential: We place functional constraints on the shape of the inflaton potential from the cosmic microwave background through a variant of the generalized slow roll approximation that allows large amplitude, rapidly changing deviations from scale-free conditions....
Quijote-PNG: Quasi-maximum likelihood estimation of Primordial Non-Gaussianity in the non-linear dark matter density field: Future Large Scale Structure surveys are expected to improve over current bounds on primordial non-Gaussianity (PNG), with a significant impact on our understanding of early Universe physics. Th...
Towards a universal model for the density profiles of dark matter haloes: It is well established from cosmological simulations that dark matter haloes are not precisely self-similar and an additional parameter, beyond their concentration, is required to accurately describe their spherically-averaged mass density profil...
Dark Matter Structures in the Universe: Prospects for Optical Astronomy in the Next Decade: The Cold Dark Matter theory of gravitationally-driven hierarchical structure formation has earned its status as a paradigm by explaining the distribution of matter over large spans of cosmic distance and time. However, its cen...
The Scale of Cosmic Isotropy: The most fundamental premise to the standard model of the universe, the Cosmological Principle (CP), states that the large-scale properties of the universe are the same in all directions and at all comoving positions. Demonstrating this theoretical hypothesis has proven to be a formidable ...
Using Dark Matter Haloes to Learn about Cosmic Acceleration: A New Proposal for a Universal Mass Function: Structure formation provides a strong test of any cosmic acceleration model because a successful dark energy model must not inhibit {\black or overpredict} the development of observed large-scale structures. Tra...
Simulating the universe on an intercontinental grid of supercomputers: Understanding the universe is hampered by the elusiveness of its most common constituent, cold dark matter. Almost impossible to observe, dark matter can be studied effectively by means of simulation and there is probably no other research field whe...
Primordial Planets Explain Interstellar Dust, the Formation of Life; and Falsify Dark Energy: Hydrogravitional-dynamics (HGD) cosmology of Gibson/Schild 1996 predicts proto-globular-star-cluster PGC clumps of Earth-mass planets fragmented from plasma at ~0.3 Myr. Protogalaxies retained the ~0.03 Myr baryonic density ...
Confrontation of Top-Hat Spherical Collapse against Dark Halos from Cosmological N-Body Simulations: The top-hat spherical collapse model (TSC) is one of the most fundamental analytical frameworks to describe the non-linear growth of cosmic structure. TSC has motivated, and been widely applied in, various researches ...
SN 2008ha: An Extremely Low Luminosity and Extremely Low Energy Supernova: We present ultraviolet, optical, and near-infrared photometry as well as optical spectra of the peculiar supernova (SN) 2008ha. SN 2008ha had a very low peak luminosity, reaching only M_V = -14.2 mag, and low line velocities of only ~2000 km/s...
Natural Neutrino Dark Energy: A new class of neutrino dark energy models is presented. The new models are characterized by the lack of exotic particles or couplings that violate the standard model symmetry. It is shown that these models lead to several concrete predictions for the dark energy equation of state, as well...
Toy model studies of tuning and typicality with an eye toward cosmology: We investigate a number of simple toy models to explore interesting relationships between dynamics and typicality. We start with an infinite model that has been proposed as an illustration of how non-ergodic dynamics can produce interesting featur...
Results from the observation of extragalactic objects with the MAGIC telescope: In the last couple of years the Magic air Cherenkov telescope has made significant contributions to very high energy $\gamma$-ray astronomy. These include the detection of the galactic binary system LSI +61 303 and the observation of puls...
Inflation after Planck and BICEP2: We discuss the inflationary paradigm, how it can be tested, and how various models of inflation fare in the light of data from Planck and BICEP2. We introduce inflation and reheating, and discuss temperature and polarisation anisotropies in the cosmic microwave background radiation du...
Cosmological constraints on induced gravity dark energy models: We study induced gravity dark energy models coupled with a simple monomial potential $\propto \sigma^n$ and a positive exponent $n$. These simple potentials lead to viable dark energy models with a weak dependence on the exponent, which characterizes the a...
Galaxy populations in the Antlia cluster - III. Properties of faint early-type galaxies: (Abridge) We present a new analysis of the early-type galaxy population in the central region of the Antlia cluster, focusing on the faint systems like dwarf ellipticals (dE) and dwarf spheroidals (dSph). We confirm 22 early-type...
A Dark Matter Hurricane: Measuring the S1 Stream with Dark Matter Detectors: The recently discovered S1 stream passes through the Solar neighbourhood on a low inclination, counter-rotating orbit. The progenitor of S1 is a dwarf galaxy with a total mass comparable to the present-day Fornax dwarf spheroidal, so the str...
Analytic marginalization of $N(z)$ uncertainties in tomographic galaxy surveys: We present a new method to marginalize over uncertainties in redshift distributions, $N(z)$, within tomographic cosmological analyses applicable to current and upcoming photometric galaxy surveys. We allow for arbitrary deviations from th...
The Fate of Dwarf Galaxies in Clusters and the Origin of Intracluster Stars: This thesis presents a review of related important concepts in cosmology followed by details of the author's role in a research project on the origin of intracluster light. The author's role in the development of the simulations varied from ...
Inferring the dark matter splashback radius from cluster gas and observable profiles in the FLAMINGO simulations: The splashback radius, coinciding with the minimum in the dark matter radial density gradient, is thought to be a universal definition of the edge of a dark matter halo. Observational methods to detect it...
Microlensing in H1413+117 : disentangling line profile emission and absorption in a broad absorption line quasar: On the basis of 16 years of spectroscopic observations of the four components of the gravitationally lensed broad absorption line (BAL) quasar H1413+117, covering the ultraviolet to visible rest-frame spe...
Hubble parameter data constraints on dark energy: We use Hubble parameter versus redshift data from Stern, et al(2010) and Gazta\~{n}aga, et al (2009) to place constraints on model parameters of constant and time-evolving dark energy cosmological models. These constraints are consistent with (through not as restrictive...
Suspended and restored activities of A Nearby Super Massive Black Hole: The discovery of spectral type transition of active galactic nuclei (AGNs), the so-called changing-look(CL) phenomenon, challenges the widely accepted AGN paradigm, not only in the orientation based Unified Model, but also in the standard disk mode...
A measurement of Hubble's Constant using Fast Radio Bursts: We constrain the Hubble constant H$_0$ using Fast Radio Burst (FRB) observations from the Australian Square Kilometre Array Pathfinder (ASKAP) and Murriyang (Parkes) radio telescopes. We use the redshift-dispersion measure (`Macquart') relationship, accounting...
Extended Schmidt Law: Role Of Existing Stars In Current Star Formation: We propose an "extended Schmidt law" with explicit dependence of the star formation efficiency (SFE=SFR/Mgas) on the stellar mass surface density. This relation has a power-law index of 0.48+-0.04 and an 1-sigma observed scatter on the SFE of 0.4 d...
The Shape of Dark Matter Haloes in the Aquarius Simulations: Evolution and Memory: We use the high resolution cosmological N-body simulations from the Aquarius project to investigate in detail the mechanisms that determine the shape of Milky Way-type dark matter haloes. We find that, when measured at the instantaneou...
Velocity Evolution and the Intrinsic Color of Type Ia Supernovae: To understand how best to use observations of Type Ia supernovae (SNe Ia) to obtain precise and accurate distances, we investigate the relations between spectra of SNe Ia and their intrinsic colors. Using a sample of 1630 optical spectra of 255 SNe, base...
Modeling Neutrino-Induced Scale-Dependent Galaxy Clustering for Photometric Galaxy Surveys: The increasing statistical precision of photometric redshift surveys requires improved accuracy of theoretical predictions for large-scale structure observables to obtain unbiased cosmological constraints. In $\Lambda$CDM cosm...
A standard siren measurement of the Hubble constant using gravitational wave events from the first three LIGO/Virgo observing runs and the DESI Legacy Survey: We present a new constraint on the Hubble constant $H_0$ using a sample of well-localized gravitational wave (GW) events detected during the first three LIGO...
Primordial magnetic fields from the string network: Cosmic strings are a type of cosmic defect formed by a symmetry-breaking phase transition in the early universe. Individual strings would have gathered to build a network, and their dynamical motion would induce scalar--, vector-- and tensor--type perturbations. In th...
Comparison of Recent SnIa datasets: We rank the six latest Type Ia supernova (SnIa) datasets (Constitution (C), Union (U), ESSENCE (Davis) (E), Gold06 (G), SNLS 1yr (S) and SDSS-II (D)) in the context of the Chevalier-Polarski-Linder (CPL) parametrization $w(a)=w_0+w_1 (1-a)$, according to their Figure of Merit (FoM), ...
Relativistic effects in the large-scale structure with effective dark energy fluids: We study the imprints of an effective dark energy fluid in the large scale structure of the universe through the observed angular power spectrum of galaxies in the relativistic regime. We adopt the phenomenological approach that intr...
Do Baryons Alter the Halos of Low Surface Brightness Galaxies?: High-quality observations of dark matter-dominated low surface brightness (LSB) galaxies indicate that, in contrast to the triaxial, centrally-concentrated cuspy halos formed in collisionless simulations of halo assembly, these galaxies reside in round, ro...
Multiwavelength perspective of AGN evolution: Discovering and studying obscured AGN at z>1-3 is important not only to complete the AGN census, but also because they can pinpoint galaxies where nuclear accretion and star-formation are coeval, and mark the onset of AGN feedback. We present the latest results on the chara...
The $\rm{Y_{SZ,Planck} - Y_{SZ,XMM}}$ scaling relation and its difference between cool-core and non-cool-core clusters: We construct a sample of 70 clusters using data from XMM-Newton and Planck to investigate the $Y_{\rm SZ,Planck}-Y_{\rm SZ, XMM}$ scaling relation and the cool-core influences on the relation. $Y_{\...
Evolution of velocity dispersion along cold collisionless flows: The infall of cold dark matter onto a galaxy produces cold collisionless flows and caustics in its halo. If a signal is found in the cavity detector of dark matter axions, the flows will be readily apparent as peaks in the energy spectrum of photons from ...
The Universal Einstein Radius Distribution from 10,000 SDSS Clusters: We present results from strong-lens modelling of 10,000 SDSS clusters, to establish the universal distribution of Einstein radii. Detailed lensing analyses have shown that the inner mass distribution of clusters can be accurately modelled by assuming...
A tale of many $H_0$: The Hubble parameter $H_0$, is not a univocally-defined quantity: it relates redshifts to distances in the near Universe, but is also a key parameter of the $\Lambda$CDM standard cosmological model. As such, $H_0$ affects several physical processes at different cosmic epochs, and multiple observab...
Implications of primordial power spectra with statistical anisotropy on CMB temperature fluctuation and polarizations: Both the Wilkinson Microwave Anisotropy Probe (WMAP) and Planck observations reported the hemispherical asymmetry of the cosmic microwave background (CMB) temperature fluctuation. The hemispherical a...
The impact of the observed baryon distribution in haloes on the total matter power spectrum: The interpretation of upcoming weak gravitational lensing surveys depends critically on our understanding of the matter power spectrum on scales $k < 10 h/\mathrm{Mpc}$, where baryonic processes are important. We study the im...
Chiral Effects and Cosmic Magnetic Fields: In the presence of cosmic chiral asymmetry, chiral-vorticity and chiral-magnetic effects can play an important role in the generation and evolution of magnetic fields in the early universe. We include these chiral effects in the magnetic field equations and find solutions unde...
Probing the Consistency of Cosmological Contours for Supernova Cosmology: As the scale of cosmological surveys increases, so does the complexity in the analyses. This complexity can often make it difficult to derive the underlying principles, necessitating statistically rigorous testing to ensure the results of an anal...
The Recent Star Formation History of NGC 5102: We present Hubble Space Telescope photometry of young stars in NGC 5102, a nearby gas-rich post-starburst S0 galaxy with a bright young stellar nucleus. We use the IAC-pop/MinnIAC algorithm to derive the recent star formation history in three fields in the bulge and disk o...
Gravitational lensing by wave dark matter halos: Wave Dark Matter (WaveDM) has recently gained attention as a viable candidate to account for the dark matter content of the Universe. In this paper we explore the extent to which dark matter halos in this model, and under what conditions, are able to reproduce strong len...
Radio-loud AGN: is there a link between luminosity and cluster environment?: We present here the first results from the Chandra ERA (Environments of Radio-loud AGN) Large Project, characterizing the cluster environments of a sample of 26 radio-loud AGN at z ~ 0.5 that covers three decades of radio luminosity. This is...
Dark matter growth and baryon bias in an accelerating universe: We investigate the exact analytic solutions for the growths of the dark matter and the baryon in sub-horizon scale. The growth of the dark matter $\delta_{\DM}$ is related to that of the halos. Thus, the exact solution for the growth of the dark matter is ...
Euclid Assessment Study Report for the ESA Cosmic Visions: Euclid is a proposed high-precision survey mission to map the geometry of the Dark Universe with demonstrated feasibility. Euclid's Visible - Near-InfraRed imaging and spectroscopy of the extragalactic sky will further produce extensive legacy science to the bo...
TPZ : Photometric redshift PDFs and ancillary information by using prediction trees and random forests: With the growth of large photometric surveys, accurately estimating photometric redshifts, preferably as a probability density function (PDF), and fully understanding the implicit systematic uncertainties in this p...
Measuring redshift through X-ray spectroscopy of galaxy clusters: results from Chandra data and future prospects: The ubiquitous presence of the Fe line complex in the X-ray spectra of galaxy clusters offers the possibility of measuring their redshift without resorting to spectroscopic follow-up observations. In this...
Constraining $M_ν$ with the Bispectrum II: The Total Information Content of the Galaxy Bispectrum: Massive neutrinos suppress the growth of structure on small scales and leave an imprint on large-scale structure that can be measured to constrain their total mass, $M_\nu$. With standard analyses of two-point clusterin...
The first analytical expression to estimate photometric redshifts suggested by a machine: We report the first analytical expression purely constructed by a machine to determine photometric redshifts ($z_{\rm phot}$) of galaxies. A simple and reliable functional form is derived using $41,214$ galaxies from the Sloan D...
A deep ATCA 20cm radio survey of the AKARI Deep Field South near the South Ecliptic Pole: The results of a deep 20 cm radio survey at 20 cm are reported of the AKARI Deep Field South (ADF-S) near the South Ecliptic Pole (SEP), using the Australia Telescope Compact Array telescope, ATCA. The survey has 1 sigma detecti...
Target Selection and Validation of DESI Emission Line Galaxies: The Dark Energy Spectroscopic Instrument (DESI) will precisely constrain cosmic expansion and the growth of structure by collecting $\sim$40 million extra-galactic redshifts across $\sim$80\% of cosmic history and one third of the sky. The Emission Line Ga...
Mining the information content of member galaxies in the halo mass modelling: Motivated by previous findings that the magnitude gap between certain satellite galaxy and the central galaxy can be used to improve the estimation of halo mass, we carry out a systematic study of the information content of different member...
Investigating the influence of magnetic fields upon structure formation with AMIGA - a C code for cosmological magnetohydrodynamics: Despite greatly improved observational methods, the presence of magnetic fields at cosmological scales and their role in the process of large-scale structure formation still remains unc...
Transformation of the angular power spectrum of the Cosmic Microwave Background (CMB) radiation into reciprocal spaces and consequences of this approach: The formalism of solid state physics has been applied to provide an additional tool for the research of cosmological problems. It is demonstrated how this new app...
Paleo-detectors: Searching for Dark Matter with Ancient Minerals: We explore paleo-detectors as an approach to the direct detection of Weakly Interacting Massive Particle (WIMP) dark matter radically different from conventional detectors. Instead of instrumenting a (large) target mass in a laboratory in order to observ...
Multi-messenger astronomy with Centaurus A: We calculated for the nearest active galactic nucleus (AGN), Centaurus A (Cen A), the flux of high energy cosmic rays and of accompanying secondary photons and neutrinos expected from hadronic interactions in the source. We used as two basic models for the generation of ultra...
An upper limit on primordial magnetic fields from ultra-faint dwarf galaxies: The presence of primordial magnetic fields increases the minimum halo mass in which star formation is possible at high redshifts. Estimates of the dynamical mass of ultra-faint dwarf galaxies (UFDs) within their half-light radius constrain ...
Imaging Redshift Estimates for BL Lacertae Objects: We have obtained high dynamic range, good natural seeing i' images of BL Lacertae objects (BL Lacs) to search for the AGN host and thus constrain the source redshift. These objects are drawn from a sample of bright flat-spectrum radio sources that are either known (vi...
Shape Profiles and Orientation Bias for Weak and Strong Lensing Cluster Halos: We study the intrinsic shape and alignment of isodensities of galaxy cluster halos extracted from the MultiDark MDR1 cosmological simulation. We find that the simulated halos, are extremely prolate on small scales, and increasingly spheric...
Improving cosmological parameter estimation with the future gravitational-wave standard siren observation from the Einstein Telescope: Detection of gravitational waves produced by merger of binary compact objects could provide an independent way for measuring the luminosity distance to the gravitational-wave burst so...
SSGSS: The Spitzer-SDSS-GALEX Spectroscopic Survey: The Spitzer-SDSS-GALEX Spectroscopic Survey (SSGSS) provides a new sample of 101 star-forming galaxies at z < 0.2 with unprecedented multi-wavelength coverage. New mid- to far-infrared spectroscopy from the Spitzer Space Telescope is added to a rich suite of previous ...
HST/ACS Emission Line Imaging of Low Redshift 3CR Radio Galaxies I: The Data: We present 19 nearby (z<0.3) 3CR radio galaxies imaged at low- and high-excitation as part of a Cycle 15 Hubble Space Telescope snapshot survey with the Advanced Camera for Surveys. These images consist of exposures of the H-alpha (6563 \AA...
Rotation Measures of Radio Sources in Hot Galaxy Clusters: The goal of this work is to investigate the Faraday rotation measure (RM) of radio galaxies in hot galaxy clusters in order to establish a possible connection between the magnetic field strength and the gas temperature of the intracluster medium. We performed V...
Strong gravitational lensing constraints on holographic dark energy: Strong gravitational lensing (SGL) has provided an important tool for probing galaxies and cosmology. In this paper, we use the SGL data to constrain the holographic dark energy model, as well as models that have the same parameter number, such as the...
On the orientation and magnitude of the black hole spin in galactic nuclei: Massive black holes in galactic nuclei vary their mass M and spin vector J due to accretion. In this study we relax, for the first time, the assumption that accretion can be either chaotic, i.e. when the accretion episodes are randomly and is...
Star-formation in the host galaxies of radio-AGN: There exist strong evidence supporting the co-evolution of central supermassive black holes and their host galaxies. It is however still unclear what the exact role of nuclear activity, in the form of accretion onto these supermassive black holes, in this co-evolution i...
Observable Signatures of Inflaton Decays: We numerically compute features in the power-spectrum that originate from the decay of fields during inflation. Using a simple, phenomenological, multi-field setup, we increase the number of fields from a few to thousands. Whenever a field decays, its associated potential energ...
Redshift estimates for fast radio bursts and implications on intergalactic magnetic fields: Context: Fast Radio Bursts are transient radio pulses from presumably compact stellar sources of extragalactic origin. With new telescopes detecting multiple events per day, statistical methods are required in order to interpr...
Cool Gas in High Redshift Galaxies: Over the last decade, observations of the cool interstellar medium in distant galaxies via molecular and atomic fine structure line emission has gone from a curious look into a few extreme, rare objects, to a mainstream tool to study galaxy formation, out to the highest redshifts. Mo...
Mergers and interactions in SDSS type 2 quasars at z~0.3-0.4. SDSS J143027.66-005614.8: a case study: We present a compilation of HST images of 58 luminous SDSS type 2 AGNs at 0.3<z<0.4. 42 of them are type 2 quasars, which are a good representation of all optically selected SDSS type 2 quasars in this range. We find...
Constraints from thermal Sunyaev-Zeldovich cluster counts and power spectrum combined with CMB: Thermal Sunyaev-Zel'dovich effect is one of the recent probes of cosmology and large scale structures. We update constraints on cosmological parameters from galaxy clusters observed by the Planck satellite in a first attem...
Non-Abelian dynamics in the resonant decay of the Higgs after inflation: We study the resonant decay of the Higgs condensate into weak gauge bosons after inflation and estimate the corrections arising from the non-Abelian self-interactions of the gauge fields. We find that non-Abelian interaction terms induce an effect...
GLIMPSE: Accurate 3D weak lensing reconstructions using sparsity: We present GLIMPSE - Gravitational Lensing Inversion and MaPping with Sparse Estimators - a new algorithm to generate density reconstructions in three dimensions from photometric weak lensing measurements. This is an extension of earlier work in one dime...
The ATLAS3D Project-- VIII: Modelling the Formation and Evolution of Fast and Slow Rotator Early-Type Galaxies within $Λ$CDM: We propose a simple model for the origin of fast and slow rotator early-type galaxies (ETG) within the hierarchical $\Lambda$CDM scenario, that is based on the assumption that the mass fractio...
Fast Computation of First-Order Feature-Bispectrum Corrections: Features in the inflaton potential that are traversed in much less than an e-fold of the expansion can produce observably large non-Gaussianity. In these models first order corrections to the curvature mode function evolution induce effects at second order...
Evolution of the mass-richness relation for the redMaPPer catalog: The accurate determination of the galaxy cluster mass-observable relations is one of the major challenge of modern astrophysics and cosmology. We present a new statistical methodology to constrain the evolution of the mass-observable relations. Instead ...
Dust in the Early (z>1) Universe: Although dust emission at cosmological distances has only been detected a little more than a decade ago, remarkable progress has been achieved since then in characterizing the far-infrared emission of high-redshift systems. The mere fact that dust can be detected in galaxies at high re...
CMB B-mode auto-bispectrum produced by primordial gravitational waves: Gravitational waves from inflation induce polarization patterns in the cosmic microwave background (CMB). It is known that there are only two types of non-Gaussianities of the gravitaional waves in the most general scalar field theories having secon...
Planck Trispectrum Constraints on Primordial Non-Gaussianity at Cubic Order: Non-Gaussianity of the primordial density perturbations provides an important measure to constrain models of inflation. At cubic order the non-Gaussianity is captured by two parameters $\tau_{\rm NL}$ and $g_{\rm NL}$ that determine the ampl...
Revisiting Noether symmetry approach in F(R)-tachyon Model: Recently, some authors have made a falsifiable claim that Noether gauge symmetry for F(R) theory of gravity coupled to a tachyon field enforces gauge to vanish and leads to F(R) \propto R^2, with a tachyon potential V(\phi) \propto \phi^{-4}. Here, we show tha...
The Very Young Type Ia Supernova 2013dy: Discovery, and Strong Carbon Absorption in Early-Time Spectra: The Type Ia supernova (SN Ia) 2013dy in NGC 7250 (d ~ 13.7 Mpc) was discovered by the Lick Observatory Supernova Search. Combined with a prediscovery detection by the Italian Supernova Search Project, we are able t...
A new model for the extragalactic gamma-ray background: We present a two-parameter model of the extragalactic gamma-ray background (EGB) in the 0.1-100 GeV range as measured by the Large Area Telescope (LAT) onboard the Fermi satellite. The EGB can be fully explained as the sum of three distinct components, namely blaz...
Constraints on moduli cosmology from the production of dark matter and baryon isocurvature fluctuations: We set constraints on moduli cosmology from the production of dark matter -- radiation and baryon -- radiation isocurvature fluctuations through modulus decay, assuming the modulus remains light during inflation. ...
Investigating the Constraints on Primordial Features with Future Cosmic Microwave Background and Galaxy Surveys: In this article, we do a thorough investigation of the competency of the forthcoming Cosmic Microwave Background (CMB) and Galaxy surveys in probing the features in the primordial power spectrum. Primordia...
The Growth of Structure in Interacting Dark Energy Models: If dark energy interacts with dark matter, there is a change in the background evolution of the universe, since the dark matter density no longer evolves as a^{-3}. In addition, the non-gravitational interaction affects the growth of structure. In principle, th...
A field-level emulator for modeling baryonic effects across hydrodynamic simulations: We develop a new and simple method to model baryonic effects at the field level relevant for weak lensing analyses. We analyze thousands of state-of-the-art hydrodynamic simulations from the CAMELS project, each with different cosmo...
Simulating the shocks in the dissociative galaxy cluster Abell 1758N: Major mergers between massive clusters have a profound effect in the intracluster gas, which may be used as a probe of the dynamics of structure formation at the high end of the mass function. An example of such a merger is observed at the northern c...
Effects of a time-varying color-luminosity parameter $β$ on the cosmological constraints of modified gravity models: It has been found that, for the Supernova Legacy Survey three-year (SNLS3) data, there is strong evidence for the redshift-evolution of color-luminosity parameter $\beta$. In previous studies, only dar...
Newly-Discovered Globular Clusters in NGC 147 and NGC 185 from PAndAS: Using data from the Pan-Andromeda Archaeological Survey (PAndAS), we have discovered four new globular clusters (GCs) associated with the M31 dwarf elliptical (dE) satellites NGC 147 and NGC 185. Three of these are associated with NGC 147 and one wi...
Model selection results from different BAO datasets -- DE models and $Ω_K$CDM: The use of the baryonic acoustic oscillations (BAO) datasets offers a unique opportunity to connect the early universe and the late one. In this proceeding, we discuss recent results that used a marginalised likelihood to remove the $H_0-r...
The Line Polarization Within a Giant Lyman-alpha Nebula: Recent theoretical work has suggested that Lyman-alpha nebulae could be substantially polarized in the Lyman-alpha emission line, depending on the geometry, kinematics, and powering mechanism at work. Polarization observations can therefore provide a useful const...
Can baryon asymmetry be explained by a large initial value before inflation?: We show that the baryon asymmetry of the Universe cannot be explained by a large initial value before inflation because it inevitably predicts correlated baryon isocurvature perturbations that are already excluded by cosmic microwave backgr...
The BACCO simulation project: biased tracers in real space: We present an emulator for the two-point clustering of biased tracers in real space. We construct this emulator using neural networks calibrated with more than $400$ cosmological models in a 8-dimensional cosmological parameter space that includes massive neut...
The impact of weak lensing on Type Ia supernovae luminosity distances: When Type Ia supernovae are used to infer cosmological parameters, their luminosities are compared to those from a homogeneous cosmology. In this note we propose a test to examine to what degree SN Ia have been observed on lines of sight where the a...
Sardinia Radio Telescope observations of the Coma Cluster: We present deep total intensity and polarization observations of the Coma cluster at 1.4 and 6.6 GHz performed with the Sardinia Radio Telescope. By combining the single-dish 1.4 GHz data with archival Very Large Array observations we obtain new images of the c...
Augmenting the power of time-delay cosmography in lens galaxy clusters by probing their member galaxies I. Type Ia supernovae: We present a simple and promising new method to measure the expansion rate and the geometry of the universe that combines observations related to the time delays between the multiple images o...
A Joint Model of the X-ray And Infrared Extragalactic Backgrounds: I. Model Construction And First Results: We present an extragalactic population model of the cosmic background light to interpret the rich high-quality survey data in the X-ray and IR bands. The model incorporates star-formation and supermassive black...
Cosmology with extragalactic proper motions: harmonic formalism, estimators, and forecasts: We conduct a thorough study into the feasibility of measuring large-scale correlated proper motions of galaxies with astrometric surveys. We introduce a harmonic formalism for analysing proper motions and their correlation fun...
Imprint of Inhomogeneous and Anisotropic Primordial Power Spectrum on CMB Polarization: We consider an inhomogeneous model and independently an anisotropic model of primordial power spectrum in order to describe the observed hemispherical anisotropy in Cosmic Microwave Background Radiation. This anisotropy can be par...
Measuring the History of Cosmic Reionization using the 21-cm Difference PDF: During cosmic reionization, the 21-cm brightness fluctuations were highly non-Gaussian, and complementary statistics can be extracted from the distribution of pixel brightness temperatures that are not derivable from the 21-cm power spectrum...
Constraints on the Reheating Parameters after Gauss-Bonnet Inflation from the Primordial Gravitational Waves: We study the effects of the Gauss-Bonnet term on the energy spectrum of inflationary gravitational waves. The models of inflation are classified into two types based on their predictions for the tensor power ...
Galactic disks and their evolution: We consider the key problems related to measuring the mass of stellar disks and dark halos in galaxies and to explaining the observed properties of disks formed in massive dark halos.
$g_{\rm NL}$ in the curvaton model constrained by PLANCK: As a simplest extension to the mass-term curvaton model, the curvaton model with a polynomial potential can relax the restricted constraint from PLANCK due to the non-linear dynamics of curvaton field before it decays. We find that there is still a big room for ...
The generalized evolution of linear bias: a tool to test gravity: We derive an exact analytical solution for the redshift evolution of linear and scale-independent bias, by solving a second order differential equation based on linear perturbation theory. This bias evolution model is applicable to all different types of...
Gravitational Waves Notes, Issue #5 : "The Capra research programme for capture of small compact objects by massive black holes": GW Notes was born from the need for a journal where the distinct communities involved in gravitation wave research might gather. While these three communities - astrophysics, general relat...
Impact of Redshift Information on Cosmological Applications with Next-Generation Radio Surveys: In this paper, we explore how the forthcoming generation of large-scale radio continuum surveys, with the inclusion of some degree of redshift information, can constrain cosmological parameters. By cross-matching these rad...
Primordial black holes from scalar field evolution in the early universe: Scalar condensates with large expectation values can form in the early universe, for example, in theories with supersymmetry. The condensate can undergo fragmentation into Q-balls before decaying. If the Q-balls dominate the energy density for so...
Estimating Cosmological Parameters from the Dark Matter Distribution: A grand challenge of the 21st century cosmology is to accurately estimate the cosmological parameters of our Universe. A major approach to estimating the cosmological parameters is to use the large-scale matter distribution of the Universe. Galaxy su...
Updated Bounds on Sum of Neutrino Masses in Various Cosmological Scenarios: We present strong bounds on the sum of three active neutrino masses ($\sum m_{\nu}$) in various cosmological models. We use the following baseline datasets: CMB temperature data from Planck 2015, BAO measurements from SDSS-III BOSS DR12, the ...
Magnetic field evolution in cosmic filaments with LOFAR data: Measuring the magnetic field in cosmic filaments reveals how the Universe is magnetised and the process that magnetised it. Using the Rotation Measures (RM) at 144-MHz from the LoTSS DR2 data, we analyse the rms of the RM extragalactic component as a functio...
Nonlinear growth of structure in cosmologies with damped matter fluctuations: We investigate the nonlinear evolution of structure in variants of the standard cosmological model which display damped density fluctuations relative to cold dark matter (e.g. in which cold dark matter is replaced by warm or interacting DM)...
Detecting Galaxy Clusters in the DLS and CARS: a Bayesian Cluster Finder: The detection of galaxy clusters in present and future surveys enables measuring mass-to-light ratios, clustering properties or galaxy cluster abundances and therefore, constraining cosmological parameters. We present a new technique for detectin...
Determining the escape fraction of ionizing photons during reionization with the GRB derived star-formation rate: The fraction of ionizing photons that escape their host galaxies and so are able to ionize hydrogen in the inter-galactic medium (IGM) is a critical parameter in analyses of the reionization era and early...
The optical afterglows and host galaxies of three short/hard gamma-ray bursts: Short GRBs are commonly thought to originate from the merging of double compact object binaries but direct evidence for this scenario is still missing. Optical observations of short GRBs allow us to measure redshifts, firmly identify host ...
A search for cosmic topology in the final WMAP data: A search for matched circle pairs of similar temperature fluctuations in the final WMAP 9yr data is carried out. Such a signature is expected if the space of the Universe is multiply connected. We investigate the relation between the pixel resolution of cosmic microw...
VLT diffraction-limited imaging at 11 and 18 micron of the nearest active galactic nuclei: Mid-infrared imaging at resolutions of 300 mas of the central kpc region of 13 nearby, well-known active galaxies is presented. The bulk of the mid-IR emission is concentrated on an unresolved central source within a size of le...
Distances to Dwarf Galaxies of the Canes Venatici I Cloud: We determined the spatial structure of the scattered concentration of galaxies in the Canes Venatici constellation. We redefined the distances for 30 galaxies of this region using the deep images from the Hubble Space Telescope archive with the WFPC2 and ACS ca...
Low CO Luminosities in Dwarf Galaxies: [Abridged] We present maps of CO 2-1 emission covering the entire star-forming disks of 16 nearby dwarf galaxies observed by the IRAM HERACLES survey. The data have 13 arcsec angular resolution, ~250 pc at our average distance of 4 Mpc, and sample the galaxies by 10-1000 resolutio...
Estimating the angular power spectrum of the gravitational-wave background in the presence of shot noise: There has been much recent interest in studying anisotropies in the astrophysical gravitational-wave (GW) background, as these could provide us with interesting new information about galaxy clustering and large-s...
Improving and extending non-Poissonian distributions for satellite galaxies sampling in HOD: applications to eBOSS ELGs: Halo Occupation Distribution (HOD) models help us to connect observations and theory, by assigning galaxies to dark matter haloes. In this work we study one of the components of HOD models: the pro...
Generation of Curvature Perturbations with Extra Anisotropic Stress: We study the evolution of curvature perturbations and the cosmic microwave background (CMB) power spectrum in the presence of an hypothesized extra anisotropic stress which might arise, for example, from the dark radiation term in brane-world cosmolog...
Weak lensing with 21cm intensity mapping at $z \sim 2-3$: We study how 21 cm intensity mapping can be used to measure gravitational lensing over a wide range of redshift. This can extend weak lensing measurements to higher redshifts than are accessible with conventional galaxy surveys. We construct a convergence estima...
Accurate initial conditions in mixed Dark Matter--Baryon simulations: We quantify the error in the results of mixed baryon--dark-matter hydrodynamic simulations, stemming from outdated approximations for the generation of initial conditions. The error at redshift 0 in contemporary large simulations, is of the order of ...
The Impact of Neutral Intergalactic Gas on Lyman-$α$ Intensity Mapping During Reionization: We present the first simulations of the high-redshift Ly$\alpha$ intensity field that account for scattering in the intergalactic medium (IGM). Using a 3D Monte Carlo radiative transfer code, we find that Ly$\alpha$ scattering...
Viable scalar spectral tilt and tensor-to-scalar ratio in near-matter bounces: In a recent work, we had constructed a model consisting of two fields---a canonical scalar field and a non-canonical ghost field---that had sourced a symmetric matter bounce scenario. The model had involved only one parameter, viz. the sca...
Fast Mock Catalog Generation for Large Scale Structure Modeling: To understand the universe and to interpret the cosmological parameters governing its evolution it is necessary to contrast the data from galaxy surveys with simulation. Typically it entails using computationally expensive N -body simulations. Computation...
The galaxy cluster outskirts probed by Chandra: We studied the physical properties of the intracluster medium in the virialization region of a sample of 320 clusters ($0.056 <z< 1.24$, $kT>3$ keV) in the Chandra archive. With the emission measure profiles from this large sample, the typical gas density, gas slope and g...
Galactic Dynamics and Local Dark Matter: The concordance Lambda Cold Dark Matter (Lambda-CDM) model for the formation of structure in the Universe, while remarkably successful at describing observations of structure on large scales, continues to be challenged by observations on galactic scales. Fortunately, CDM models ...
The relation between dynamics and star formation in barred galaxies: We analyze optical and near-infrared data of a sample of 11 barred spiral galaxies, in order to establish a connection between star formation and bar/spiral dynamics. We find that 22 regions located in the bars, and 20 regions in the spiral arms beyon...
Uv-to-fir analysis of spitzer/irac sources in the extended groth strip i: Multi-wavelength photometry and spectral energy distributions: We present an IRAC 3.6+4.5 microns selected catalog in the Extended Groth Strip (EGS) containing photometry from the ultraviolet to the far-infrared and stellar parameters derived f...
Model-Independent Measurements of Cosmic Expansion and Growth at z=0.57 Using the Anisotropic Clustering of CMASS Galaxies From the Sloan Digital Sky Survey Data Release 9: We analyze the anisotropic two dimensional galaxy correlation function (2DCF) of the CMASS galaxy sample from the Sloan Digital Sky Survey Data...
Chandra and XMM-Newton Observations of the Bimodal Planck SZ-detected Cluster PLCKG345.40-39.34 (A3716) with High and Low Entropy Subcluster Cores: We present results from Chandra, XMM-Newton, and ROSAT observations of the Planck SZ-detected cluster A3716 (PLCKG345.40-39.34 - G345). We show that G345 is, in fact, two...
Comparison of weak lensing by NFW and Einasto halos and systematic errors: Recent N-body simulations have shown that Einasto radial profiles provide the most accurate description of dark matter halos. Predictions based on the traditional NFW functional form may fail to describe the structural properties of cosmic obj...
Quantifying galactic morphological transformations in the cluster environment: We study the effects of the cluster environment on galactic morphology by defining a dimensionless angular momentum parameter $\lambda_{d}$, to obtain a quantitative and objective measure of galaxy type. The use of this physical parameter ...
Redshift Weights for Baryon Acoustic Oscillations : Application to Mock Galaxy Catalogs: Large redshift surveys capable of measuring the Baryon Acoustic Oscillation (BAO) signal have proven to be an effective way of measuring the distance-redshift relation in cosmology. Building off the work in Zhu et al. (2015), we ...
The case of 1.5 eV neutrino hot dark matter: The lensing data of the galaxy cluster Abell 1689 can be explained by an isothermal fermion model with a mass of 1-2 eV. The best candidate is the 1.5 eV neutrino; its mass will be searched down to 0.2 eV in KATRIN 2015. If its righthanded (sterile) modes were created too, t...
Fast Bayesian inference for slow-roll inflation: We present and discuss a new approach increasing by orders of magnitude the speed of performing Bayesian inference and parameter estimation within the framework of slow-roll inflation. The method relies on the determination of an effective likelihood for inflation which ...
Peculiar Transverse Velocities of Galaxies from Quasar Microlensing. Tentative Estimate of the Peculiar Velocity Dispersion at $z\sim 0.5$: We propose to use the flux variability of lensed quasar images induced by gravitational microlensing to measure the transverse peculiar velocity of lens galaxies over a wide rang...
Primordial Black Holes from Thermal Inflation: We present a novel mechanism for the production of primordial black holes (PBHs). The mechanism is based on a period of thermal inflation followed by fast-roll inflation due to tachyonic mass of order the Hubble scale. Large perturbations are generated at the end of the th...
Evolution in the Escape Fraction of Ionizing Photons and the Decline in Strong Lya Emission from z>6 Galaxies: The rapid decline in the number of strong Lyman Alpha (Lya) emitting galaxies at z > 6 provides evidence for neutral hydrogen in the IGM, but is difficult to explain with plausible models for reionization. W...
Testing primordial non-Gaussianities on galactic scales at high redshift: Primordial non-Gaussianities provide an important test of inflationary models. Although the Planck CMB experiment has produced strong limits on non-Gaussianity on scales of clusters, there is still room for considerable non-Gaussianity on galacti...
Cooling Improves Cosmic Microwave Background Map-Making When Low-Frequency Noise is Large: In the context of Cosmic Microwave Background data analysis, we study the solution to the equation that transforms scanning data into a map. As originally suggested in "messenger" methods for solving linear systems, we split th...
Homogeneous cosmology with aggressively expanding civilizations: In the context of a homogeneous universe, we note that the appearance of aggressively expanding advanced life is geometrically similar to the process of nucleation and bubble growth in a first-order cosmological phase transition. We exploit this similarit...
The SRG/eROSITA All-Sky Survey: Cosmology Constraints from Cluster Abundances in the Western Galactic Hemisphere: The cluster mass function traces the growth of linear density perturbations and provides valuable insights into the growth of structures, the nature of dark matter, and the cosmological parameters governi...
Implementing the DC Mode in Cosmological Simulations with Supercomoving Variables: As emphasized by previous studies, proper treatment of the density fluctuation on the fundamental scale of a cosmological simulation volume - the "DC mode" - is critical for accurate modeling of spatial correlations on scales > 10% of ...
The circumnuclear environment of the peculiar galaxy NGC 3310: Gas and star velocity dispersions have been derived for eight circumnuclear star-forming regions (CNSFRs) and the nucleus of the spiral galaxy NGC3310 using high resolution spectroscopy in the blue and far red. Stellar velocity dispersions have been obtaine...
A Tale of Two Scales: Screening in Large Scale Structure: The perturbative treatment of dark matter in structure formation relies on the existence of a well-defined expansion parameter, $k/k_{\rm NL}$, with $k_{\rm NL}$ signalling the onset and ultimately the leading role of non-linearities in the system. Cosmologies b...
The Araucaria Project. The Distance to the Sculptor Galaxy NGC 247 from Near-Infrared Photometry of Cepheid Variables: We have obtained deep near-infrared images in J and K filters of four fields in the Sculptor Group spiral galaxy NGC 247 with the ESO VLT and ISAAC camera. For a sample of ten Cepheids in these field...
DISCO-DJ I: a differentiable Einstein-Boltzmann solver for cosmology: We present the Einstein-Boltzmann module of the DISCO-DJ (DIfferentiable Simulations for COsmology - Done with JAX) software package. This module implements a fully differentiable solver for the linearised cosmological Einstein-Boltzmann equations in...
The Cosmic Abundance of Classical Milky Way Satellites: We study the abundance of satellites akin to the brightest, classical dwarf spheroidals around galaxies similar in magnitude and isolation to the Milky Way and M31 in the Sloan Digital Sky Survey. From a combination of photometric and spectroscopic redshifts, we b...
The metallicity profile of M31 from spectroscopy of hundreds of HII regions and PNe: The oxygen abundance gradients among nebular emission line regions in spiral galaxies have been used as important constraints for models of chemical evolution. We present the largest ever full-wavelength optical spectroscopic sample ...
Precise Identifications of Submillimeter Galaxies: Measuring the History of Massive Star-Forming Galaxies to z>5: We carried out extremely sensitive Submillimeter Array (SMA) 340 GHz (860 micron) continuum imaging of a complete sample of SCUBA 850 micron sources (>4 sigma) with fluxes >3 mJy in the GOODS-N. Using the...
Active Galaxies and the Study of Black Hole Demographics: We discuss the critical importance of black hole mass indicators based on scaling relations in active galaxies. We highlight outstanding uncertainties in these methods and potential paths to substantial progress in the next decade.
A star-bursting proto-cluster in making associated to a radio galaxy at z=2.53 discovered by H_alpha imaging: We report a discovery of a proto-cluster in vigorous assembly and hosting strong star forming activities, associated to a radio galaxy USS 1558-003 at z=2.53, as traced by a wide-field narrow-band H_alpha ima...