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Recovering $Λ$CDM Model From a Cosmographic Study: Using the mathematical definitions of deceleration and jerk parameters we obtain a general differential equation for squared Hubble parameter. For a constant jerk, this differential equation leads to an exact function for Hubble parameter. By the aid of this exact Hubb...
Stellar Populations of Elliptical Galaxies in the Local Universe: We study the stellar populations of 1,923 elliptical galaxies at z<0.05 selected from the Sloan Digital Sky Survey as a function of velocity dispersion, sigma, and environment. We construct average, high signal-to-noise spectra and find the following: (1...
Distant galaxy clusters in the XMM Large Scale Structure survey: (Abridged) Distant galaxy clusters provide important tests of the growth of large scale structure in addition to highlighting the process of galaxy evolution in a consistently defined environment at large look back time. We present a sample of 22 distant ...
Constraints on deviations from $Λ$CDM within Horndeski gravity: Recent anomalies found in cosmological datasets such as the low multipoles of the Cosmic Microwave Background or the low redshift amplitude and growth of clustering measured by e.g., abundance of galaxy clusters and redshift space distortions in galaxy sur...
Herschel-ATLAS: deep HST/WFC3 imaging of strongly lensed submillimeter galaxies: We report on deep near-infrared observations obtained with the Wide Field Camera 3 (WFC3) onboard the Hubble Space Telescope (HST) of the first five confirmed gravitational lensing events discovered by the Herschel Astrophysical Terahert...
Understanding the relation between thermal Sunyaev-Zeldovich decrement and halo mass using the SIMBA and TNG simulations: The relation between the integrated thermal Sunyaev-Zeldovich (tSZ) $y$-decrement versus halo mass ($Y$--$M$) can potentially constrain galaxy formation models, if theoretical and observational sy...
Mass accretion rates of the HectoMAP clusters of galaxies: We estimate the mass accretion rate (MAR) of the 346 clusters of galaxies in the HectoMAP Cluster Survey. The clusters span the redshift range $0.17-0.42$ and the $M_{200}$ mass range $\approx (0.5 - 3.5)\cdot 10^{14} M_\odot$. The MAR estimate is based on the ...
Dwarf Galaxies and the Cosmic Web: We use a cosmological simulation of the formation of the Local Group of Galaxies to identify a mechanism that enables the removal of baryons from low-mass halos without appealing to feedback or reionization. As the Local Group forms, matter bound to it develops a network of filaments ...
Frontier Fields: Subaru Weak-Lensing Analysis of the Merging Galaxy Cluster A2744: We present a weak-lensing analysis of the merging {\em Frontier Fields} (FF) cluster Abell~2744 using new Subaru/Suprime-Cam imaging. The wide-field lensing mass distribution reveals this cluster is comprised of four distinct substruct...
Fast simulations for intensity mapping experiments: We present a code to generate mock observations of 21 cm intensity mapping experiments. The emphasis of the code is on reducing the computational cost of running a full-blown simulation, trading computational time for accuracy. The code can be used to generate indepen...
Tensor B mode and stochastic Faraday mixing: This paper investigates the Faraday effect as a different source of B mode polarization. The E mode polarization is Faraday rotated provided a stochastic large-scale magnetic field is present prior to photon decoupling. In the first part of the paper we discuss the case wher...
Galaxy Zoo: dust lane early-type galaxies are tracers of recent, gas-rich minor mergers: We present the second of two papers concerning the origin and evolution of local early-type galaxies exhibiting dust features. We use optical and radio data to examine the nature of active galactic nucleus (AGN) activity in these...
Inflation and Alternatives with Blue Tensor Spectra: We study the tilt of the primordial gravitational waves spectrum. A hint of blue tilt is shown from analyzing the BICEP2 and POLARBEAR data. Motivated by this, we explore the possibilities of blue tensor spectra from the very early universe cosmology models, includin...
Cosmology with AGN dust time lags -- Simulating the new VEILS survey: The time lag between optical and near-infrared continuum emission in active galactic nuclei (AGN) shows a tight correlation with luminosity and has been proposed as a standardisable candle for cosmology. In this paper, we explore the use of these AGN...
Using Colors to Improve Photometric Metallicity Estimates for Galaxies: There is a well known correlation between the mass and metallicity of star-forming galaxies. Because mass is correlated with luminosity, this relation is often exploited, when spectroscopy is not available, to estimate galaxy metallicities based on...
Probing Inhomogeneity in the Helium Ionizing UV Background: We present an analysis combining the simultaneous measurement of intergalactic absorption by hydrogen (H I), helium (He II) and oxygen (O VI) in UV and optical quasar spectra. The combination of the H I and He II Lyman-alpha forests through $\eta$ (the ratio o...
Structure Decomposition for the Luminous Disk Galaxies in the NGC 524 Group: Members of the NGC 524 group of galaxies are studied using data obtained on the 6m telescope of the Special Astrophysical Observatory of the Russian Academy of Sciences, with the SCORPIO reducer in an imaging mode. Surface photometry has bee...
Quintessence or Phantom: Study of scalar field dark energy models through a general parametrization of the Hubble parameter: In this work we propose a simple general parametrization scheme of the Hubble parameter for the scalar field dark energy models. In our approach it is possible to incorporate both the quintesse...
Graviton production in non-inflationary cosmology: We discuss the creation of massless particles in a Universe, which transits from a radiation-dominated era to any other expansion law. We calculate in detail the generation of gravitons during the transition to a matter dominated era. We show that the resulting gravito...
The small scale power asymmetry in the cosmic microwave background: We investigate the hemispherical power asymmetry in the cosmic microwave background on small angular scales. We find an anomalously high asymmetry in the multipole range l=601-2048, with a naive statistical significance of 6.5 sigma. However, we show t...
Galaxy number-count dipole and superhorizon fluctuations: In view of the growing tension between the dipole anisotropy of number counts of cosmologically distant sources and of the cosmic microwave background (CMB), we investigate the number count dipole induced by primordial perturbations with wavelength comparable to...
Phenomenology of a Pseudo-Scalar Inflaton: Naturally Large Nongaussianity: Many controlled realizations of chaotic inflation employ pseudo-scalar axions. Pseudo-scalars \phi are naturally coupled to gauge fields through c \phi F \tilde{F}. In the presence of this coupling, gauge field quanta are copiously produced by...
Cosmic flow around local massive galaxies: Aims. We use accurate data on distances and radial velocities of galaxies around the Local Group, as well as around 14 other massive nearby groups, to estimate their radius of the zero-velocity surface, $R_0$, which separates any group against the global cosmic expansion. Me...
Correlating correlation functions of primordial perturbations: We explore the correlations between correlation functions of the primordial curvature perturbation produced during inflation. We find that for general single field inflation, other than the source terms which depend on the model details, higher order correl...
How can gravitational-wave standard sirens and 21 cm intensity mapping jointly provide a precise late-universe cosmological probe?: In the next decades, the gravitational-wave (GW) standard siren observations and the neutral hydrogen 21-cm intensity mapping (IM) surveys, as two promising cosmological probes, will pla...
Detection of molecular gas in a distant submillimetre galaxy at z=4.76 with ATCA: We have detected the CO(2-1) transition from the submillimetre galaxy (SMG) LESSJ033229.4-275619 at z=4.755 using the new Compact Array Broadband Backend system on the Australian Telescope Compact Array. These data have identified a mas...
Designing an Optimal LSST Deep Drilling Program for Cosmology with Type Ia Supernovae: The Vera C. Rubin Observatory's Legacy Survey of Space and Time is forecast to collect a large sample of Type Ia supernovae (SNe Ia) that could be instrumental in unveiling the nature of Dark Energy. The feat, however, requires mea...
Holographic dark energy at the Ricci scale: We consider a holographic cosmological model in which the infrared cutoff is fixed by the Ricci's length and dark matter and dark energy do not evolve separately but interact non-gravitationally with one another. This substantially alleviates the cosmic coincidence problem as...
The separate and combined effects of baryon physics and neutrino free-streaming on large-scale structure: We use the cosmo-OWLS and BAHAMAS suites of cosmological hydrodynamical simulations to explore the separate and combined effects of baryon physics (particularly feedback from active galactic nuclei, AGN) and free...
The QCD Axion and Gravitational Waves in light of NANOGrav results: The North American Nanohertz Observatory for Gravitational Waves (NANOGrav) collaboration has recently reported strong evidence for a stochastic process affecting the 12.5 yr dataset of pulsar timing residuals. We show that the signal can be interprete...
Tidal alignment of galaxies: We develop an analytic model for galaxy intrinsic alignments (IA) based on the theory of tidal alignment. We calculate all relevant nonlinear corrections at one-loop order, including effects from nonlinear density evolution, galaxy biasing, and source density weighting. Contributions from d...
Tracing the merger rate of the Universe with APERTIF and ASKAP: OH maser emission at 1.67 GHz is known to be associated with regions of intense star formation within ULIRGs. As these galaxies are formed through violent mergers, studying the co-moving density of OH maser galaxies across cosmic time will allow the merger...
Constraining Dark Matter -- Dark Radiation interactions with CMB, BAO, and Lyman-$α$: Several interesting Dark Matter (DM) models invoke a dark sector leading to two types of relic particles, possibly interacting with each other: non-relativistic DM, and relativistic Dark Radiation (DR). These models have interesting...
SN and BAO constraints on (new) polynomial dark energy parametrizations: current results and forecasts: In this work we introduce two new polynomial parametrizations of dark energy and explore their correlation properties. The parameters to fit are the equation of state values at z=0 and z=0.5, which have naturally l...
Physical Properties of Spectroscopically-Confirmed Galaxies at z >= 6. I. Basic Characteristics of the Rest-Frame UV Continuum and Lyman-alpha emission: We present deep HST near-IR and Spitzer mid-IR observations of a large sample of spectroscopically-confirmed galaxies at z >= 6. The sample consists of 51 Lyman-al...
Angular Momentum Transfer and Lack of Fragmentation in Self-Gravitating Accretion Flows: Rapid inflows associated with early galaxy formation lead to the accumulation of self-gravitating gas in the centers of proto-galaxies. Such gas accumulations are prone to non-axisymmetric instabilities, as in the well-known Macl...
Remapping simulated halo catalogues in redshift space: We discuss the extension to redshift space of a rescaling algorithm, designed to alter the effective cosmology of a pre-existing simulated particle distribution or catalogue of dark matter haloes. The rescaling approach was initially developed by Angulo & White and...
21cm Forest with the SKA: An alternative to both the tomography technique and the power spectrum approach is to search for the 21cm forest, that is the 21cm absorption features against high-z radio loud sources caused by the intervening cold neutral intergalactic medium (IGM) and collapsed structures. Although the exis...
Machine Learning Cosmic Expansion History: We use the machine learning techniques, for the first time, to study the background evolution of the universe in light of 30 cosmic chronometers. From 7 machine learning algorithms, using the principle of mean squared error minimization on testing set, we find that Bayesian ri...
Testing the spherical evolution of cosmic voids: We study the spherical evolution model for voids in $\Lambda$CDM, where the evolution of voids is governed by dark energy at an earlier time than that for the whole universe or in overdensities. We show that the presence of dark energy suppresses the growth of peculiar v...
Combining clustering and abundances of galaxy clusters to test cosmology and primordial non-Gaussianity: We present the clustering of galaxy clusters as a useful addition to the common set of cosmological observables. The clustering of clusters probes the large-scale structure of the Universe, extending galaxy cluste...
On the Density profile slope of Clusters of Galaxies: The present paper extends to clusters of galaxies the study of Del Popolo (2012), concerning how the baryon-dark matter (DM) interplay shapes the density profile of dwarf galaxies. Cluster density profiles are determined taking into account dynamical friction, rando...
Non-detection of a statistically anisotropic power spectrum in large-scale structure: We search a sample of photometric luminous red galaxies (LRGs) measured by the Sloan Digital Sky Survey (SDSS) for a quadrupolar anisotropy in the primordial power spectrum, in which P(\vec{k}) is an isotropic power spectrum P(k) mu...
The Merger Rates and Mass Assembly Histories of Dark Matter Haloes in the Two Millennium Simulations: We construct merger trees of dark matter haloes and quantify their merger rates and mass growth rates using the joint dataset from the Millennium and Millennium-II simulations. The finer resolution of the Millennium-...
Observational signatures of microlensing in gravitational waves at LIGO/Virgo frequencies: Microlenses with typical stellar masses (a few ${\rm M}_{\odot}$) have traditionally been disregarded as potential sources of gravitational lensing effects at LIGO/Virgo frequencies, since the time delays are often much smaller...
Electrodynamics in an LTB scenario: In this article we analyze the electrodynamics in curved space-time in LTB metric. We calculate the most general scale factor in this inhomogeneous Universe. We also study the presence of electromagnetic field bubbles in the Universe.
Stochastic dark energy from inflationary quantum fluctuations: We study the quantum backreaction from inflationary fluctuations of a very light, non-minimally coupled spectator scalar and show that it is a viable candiate for dark energy. The problem is solved by suitably adapting the formalism of stochastic inflation....
A Free-Form mass model of the Hubble Frontier Fields Cluster AS1063 (RXC J2248.7-4431) with over one hundred constraints: We derive a free-form mass distribution for the massive cluster AS1063 (z=0.348) using the completed optical imaging from the Hubble Frontier Fields programme. Based on a subset of 11 multiply len...
Effects of active-sterile neutrino mixing during primordial nucleosynthesis: In the present work, we discuss the effects of the inclusion of sterile-active neutrino oscillations during the production of primordial light-nuclei. We assume that the sterile neutrino mass-eigenstate might oscillate with the two lightest ...
The first high-redshift cavity power measurements of cool-core galaxy clusters with the International LOFAR Telescope: Radio-mode feedback associated with the active galactic nuclei (AGN) at the cores of galaxy clusters injects large amount of energy into the intracluster medium (ICM), offsetting radiative losses thr...
Substructure lensing in galaxy clusters as a constraint on low-mass sterile neutrinos in tensor-vector-scalar theory: The straight arc of Abell 2390: Certain covariant theories of the modified Newtonian dynamics paradigm seem to require an additional hot dark matter (HDM) component - in the form of either heavy ord...
New test of the FLRW metric using the distance sum rule: We present a new test of the validity of the Friedmann-Lemaitre-Robertson-Walker (FLRW) metric, based on comparing the distance from redshift 0 to $z_1$ and from $z_1$ to $z_2$ to the distance from $0$ to $z_2$. If the universe is described by the FLRW metric, th...
Unifying all mass discrepancies with one effective gravity law?: A remarkably tight relation is observed between the Newtonian gravity sourced by the baryons and the actual gravity in galaxies of all sizes. This can be interpreted as the effect of a single effective force law depending on acceleration. This is however ...
Inflation with very small tensor-to-scalar ratio: We have investigated inflation models that predict a very small value of the tensor-to-scalar ratio, $r$. The spectral index $n_s$, and the tensor-to-scalar ratio $r$, are strictly constrained by the Planck data. $n_s$ and $r$ are sensitive to the shape and magnitude of...
Sub-millimetre galaxies in cosmological hydrodynamic simulations: Source number counts and the spatial clustering: We use large cosmological Smoothed-Particle-Hydrodynamics simulations to study the formation and evolution of sub-millimetre galaxies (SMGs). In our previous work, we studied the statistical properties o...
An HST/WFC3-IR Morphological Survey of Galaxies at z = 1.5-3.6: I. Survey Description and Morphological Properties of Star Forming Galaxies: We present the results of a 42-orbit HST/WFC3 survey of the rest-frame optical morphologies of star forming galaxies with spectroscopic redshifts in the range z=1.5-3.6. The sur...
Radiative Transfer Modeling of Lyman Alpha Emitters. I. Statistics of Spectra and Luminosity: We combine a cosmological reionization simulation with box size of 100Mpc/h on a side and a Monte Carlo Lyman-alpha (Lya) radiative transfer code to model Lyman Alpha Emitters (LAEs) at z~5.7. The model introduces Lya radiat...
SAFIR: testing the coexistence of AGN and star formation activity and the nature of the dusty torus in the local universe: We present the Seyfert and star formation Activity in the Far-InfraRed (SAFIR) project, a small (15.1h) Herschel guaranteed time proposal performing PACS and SPIRE imaging of a small sample of ne...
When is the growth index constant?: The growth index $\gamma$ is an interesting tool to assess the phenomenology of dark energy (DE) models, in particular of those beyond general relativity (GR). We investigate the possibility for DE models to allow for a constant $\gamma$ during the entire matter and DE dominated stag...
Constraints on hybrid metric-Palatini models from background evolution: In this work, we introduce two models of the hybrid metric-Palatini theory of gravitation. We explore their background evolution, showing explicitly that one recovers standard General Relativity with an effective Cosmological Constant at late times...
Dipole Anisotropy in Integrated Linearly Polarized Flux Density in NVSS Data: We study the dipole anisotropy in integrated linearly polarization flux density in NRAO VLA Sky Survey (NVSS). We extract the anisotropy parameters in the number counts, number counts weighted by polarization observables, i.e. degree of pol...
Quintessence dynamics with two scalar fields and mixed kinetic terms: The dynamical properties of a model of dark energy in which two scalar fields are coupled by a non-canonical kinetic term are studied. We show that overall the addition of the coupling has only minor effects on the dynamics of the two-field system fo...
Calculating the Hubble diagram by perturbation theory: The effect of density fluctuations upon light propagation is calculated perturbatively in a matter dominated irrotational universe. The starting point is the perturbed metric (second order in the perturbation strength), while the output is the Hubble diagram. Densi...
A Dynamical Model of the Local Group: This dynamical model for the 28 galaxies with distances less than 1.5 Mpc, and not apparently tight satellites, is constrained by the initial condition that peculiar velocities at high redshift are small and growing in accordance with the standard cosmology. The solution is a satis...
Breaking the Degeneracy: Optimal Use of Three-point Weak Lensing Statistics: We study the optimal use of third order statistics in the analysis of weak lensing by large-scale structure. These higher order statistics have long been advocated as a powerful tool to break measured degeneracies between cosmological parame...
Viscous dark fluid universe: We investigate the cosmological perturbation dynamics for a universe consisting of pressureless baryonic matter and a viscous fluid, the latter representing a unified model of the dark sector. In the homogeneous and isotropic background the \textit{total} energy density of this mixture beha...
A Minkowski Functional Analysis of the Cosmic Microwave Background Weak Lensing Convergence: Minkowski functionals are summary statistics that capture the geometric and morphological properties of fields. They are sensitive to all higher order correlations of the fields and can be used to complement more conventional...
The Ellipticity Distribution of Ambiguously Blended Objects: Using overlapping fields with space-based Hubble Space Telescope (HST) and ground-based Subaru Telescope imaging we identify a population of blended galaxies that are blended to such a large degree that they are detected as single objects in the ground-based ...
Topology of large scale under-dense regions: We investigate the large scale matter distribution adopting QSOs as matter tracer. The quasar catalogue based on the SDSS DR7 is used. The void finding algorithm is presented and statistical properties of void sizes and shapes are determined. Number of large voids in the qua...
Ongoing Star Formation In AGN Host Galaxy Disks: A View From Core-collapse Supernovae: The normalized radial distribution of young stellar populations (and cold gas) in nearby galactic disks is compared between AGN host galaxies and starforming galaxies (both with Hubble types between S0/a and Scd) by using type II s...
The first bent double lobe radio source in a known cluster filament: Constraints on the intra-filament medium: We announce the first discovery of a bent double lobe radio source (DLRS) in a known cluster filament. The bent DLRS is found at a distance of 3.4 Mpc from the center of the rich galaxy cluster, Abell~1763. ...
Strong PAH Emission from z~2 ULIRGs: Using the Infrared Spectrograph on board the Spitzer Space Telescope, we present low-resolution (64 < lambda / dlambda < 124), mid-infrared (20-38 micron) spectra of 23 high-redshift ULIRGs detected in the Bootes field of the NOAO Deep Wide-Field Survey. All of the sources were sele...
Cosmic Evolution of Star Formation In SDSS Quasar Hosts Since z=1: We present Spitzer IRS observations of a complete sample of 57 SDSS type-1 quasars at z~1. Aromatic features at 6.2 and/or 7.7 um are detected in about half of the sample and show profiles similar to those seen in normal galaxies at both low- and high-r...
The First Stars: The first stars to form in the Universe -- the so-called Population III stars -- bring an end to the cosmological Dark Ages, and exert an important influence on the formation of subsequent generations of stars and on the assembly of the first galaxies. Developing an understanding of how and when the fi...
Cosmology with massive neutrinos III: the halo mass function and an application to galaxy clusters: We use a suite of N-body simulations that incorporate massive neutrinos as an extra-set of particles to investigate their effect on the halo mass function. We show that for cosmologies with massive neutrinos the mass f...
A Novel Test of the Modified Newtonian Dynamics with Gas Rich Galaxies: The current cosmological paradigm, LCDM, requires that the mass-energy of the universe be dominated by invisible components: dark matter and dark energy. An alternative to these dark components is that the law of gravity be modified on the relevant...
Massive primordial black holes in contemporary universe: The parameters of the original log-normal mass spectrum of primordial black holes (PBH) are approximately adjusted on the basis of existing observational data on supermassive black holes in the galactic centers and the mass distribution of the near-solar mass bla...
The First Galaxies: We review our current understanding of how the first galaxies formed at the end of the cosmic dark ages, a few 100 million years after the Big Bang. Modern large telescopes discovered galaxies at redshifts greater than seven, whereas theoretical studies have just reached the degree of sophistication...
A comparative study of optical/ultraviolet variability of narrow-line Seyfert 1 and broad-line Seyfert 1 active galactic nuclei: The ensemble optical/ultraviolet variability of narrow-line Seyfert 1 (NLS1) type active galactic nuclei (AGNs) is investigated, based on a sample selected from the Sloan Digital Sky Survey...
The Low-Velocity, Rapidly Fading Type Ia Supernova 2002es: SN 2002es is a peculiar subluminous Type Ia supernova (SN Ia) with a combination of observed characteristics never before seen in a SN Ia. At maximum light, SN 2002es shares spectroscopic properties with the underluminous SN 1991bg subclass of SNe Ia, but with ...
The Completed SDSS-IV Extended Baryon Oscillation Spectroscopic Survey: N-body Mock Challenge for Galaxy Clustering Measurements: We develop a series of N-body data challenges, functional to the final analysis of the extended Baryon Oscillation Spectroscopic Survey (eBOSS) Data Release 16 (DR16) galaxy sample. The ch...
KiDS-1000 cosmology: Combined second- and third-order shear statistics: This paper performs the first cosmological parameter analysis of the KiDS-1000 data with second- and third-order shear statistics. This work builds on a series of papers that describe the roadmap to third-order shear statistics. We derive and test ...
The evolutionary sequence of sub-mm galaxies: from diffuse discs to massive compact ellipticals?: The population of compact massive galaxies observed at z > 1 are hypothesised, both observationally and in simulations, to be merger remnants of gas-rich disc galaxies. To probe such a scenario we analyse a sample of 12 ...
On interpretation of recent proper motion data for the Large Magellanic Cloud: Recent observational studies using the Hubble Space Telescope (HST) have derived the center-of-mass proper motion (CMPM) of the Large Magellanic Cloud (LMC). Although these studies carefully treated both rotation and perspective effects in...
Results on Low-Mass Weakly Interacting Massive Particles from a 11 kg d Target Exposure of DAMIC at SNOLAB (ICRC2021 Proceedings): Experimental efforts of the last decades have been unsuccessful in detecting WIMPs (Weakly Interacting Massive Particles) in the 10-to-10$^4$ GeV/$c^2$ range, thus motivating the search f...
Multi-wavelength spectroscopic probes: prospects for primordial non-Gaussianity and relativistic effects: Next-generation cosmological surveys will observe larger cosmic volumes than ever before, enabling us to access information on the primordial Universe, as well as on relativistic effects. We consider forthcoming ...
Detecting cosmic voids via maps of geometric-optics parameters: Curved-spacetime geometric-optics maps derived from a deep photometric survey should contain information about the three-dimensional matter distribution and thus about cosmic voids in the survey, despite projection effects. We explore to what degree sky-pl...
Asymmetric velocity anisotropies in remnants of collisionless mergers: Dark matter haloes in cosmological N-body simulations are affected by processes such as mergers, accretion and the gravitational interaction with baryonic matter. Typically the analysis of dark matter haloes is performed in spherical or elliptical b...
Constraints on decaying dark matter from the extragalactic gamma-ray background: If dark matter is unstable and the mass is within GeV-TeV regime, its decays produce high-energy photons that give contribution to the extragalactic gamma-ray background (EGRB). We constrain dark matter decay by analyzing the 50-month EG...
The dynamics of the giant radio galaxy 3C 457: We present multi-frequency radio observations with the Giant Metrewave Radio Telescope and Very Large Array, and X-ray observations with the X-ray Multi-Mirror Mission ({\it XMM-Newton}) telescope of the giant radio source (GRS) 3C 457. We have detected the core, lobes and...
Directional dark matter detection sensitivity of a two-phase liquid argon detector: We examine the sensitivity of a large scale two-phase liquid argon detector to the directionality of the dark matter signal. This study was performed under the assumption that, above 50 keV of recoil energy, one can determine (with so...
Ultra-low mass PBHs in the early universe can explain the PTA signal: Pulsar Timing Array collaborations have recently announced the discovery of a stochastic gravitational wave background (SGWB) at nanohertz frequencies. We analyze the GW signals from the domination of ultra-low mass primordial black holes (PBHs) in t...
Imaging the Thermal and Kinematic Sunyaev-Zel'dovich Effect Signals in a Sample of Ten Massive Galaxy Clusters: Constraints on Internal Velocity Structures and Bulk Velocities: We have imaged the Sunyaev-Zel'dovich (SZ) effect signals at 140 and 270 GHz towards ten galaxy clusters with Bolocam and AzTEC/ASTE. We al...
I Zw 18 as morphological paradigm for rapidly assembling high-z galaxies: IZw18, ever since regarded as the prototypical blue compact dwarf (BCD) galaxy, is, quite ironically, the most atypical BCD known. This is because its large exponential low-surface brightness envelope is not due to an old stellar host but entirel...
BLAST: A Far-Infrared Measurement of the History of Star Formation: We directly measure redshift evolution in the mean physical properties (far-infrared luminosity, temperature, and mass) of the galaxies that produce the cosmic infrared background (CIB), using measurements from the Balloon-borne Large Aperture Sub-mill...
Characterising large-scale structure with the REFLEX II cluster survey: We study the large-scale structure with superclusters from the REFLEX X-ray cluster survey together with cosmological N-body simulations. It is important to construct superclusters with criteria such that they are homogeneous in their properties. W...
Off-center observers versus supernovae in inhomogeneous pressure universes: Exact luminosity distance and apparent magnitude formulas are applied to Union2 557 supernovae sample in order to constrain possible position of an observer outside of the center of symmetry in spherically symmetric inhomogeneous pressure Ste...
Search for Low-Mass Dark Matter with CDMSlite Using a Profile Likelihood Fit: The Cryogenic Dark Matter Search low ionization threshold experiment (CDMSlite) searches for interactions between dark matter particles and germanium nuclei in cryogenic detectors. The experiment has achieved a low energy threshold with imp...
The GALEX view of the Herschel Reference Survey - Ultraviolet structural properties of nearby galaxies: We present GALEX far-ultraviolet (FUV) and near-ultraviolet (NUV) as well as SDSS g, r, i photometry and structural parameters for the Herschel Reference Survey, a magnitude-, volume-limited sample of nearby galaxi...
Backreaction in Growing Neutrino Quintessence: We investigate the cosmological effects of neutrino lumps in Growing Neutrino Quintessence. The strongly non-linear effects are resolved by means of numerical N-body simulations which include relativistic particles, non-linear scalar field equations and backreaction effect...
Comparing X-ray and Dynamical Mass Profiles in the Early-Type Galaxy NGC 4636: We present the results of an X-ray mass analysis of the early-type galaxy NGC 4636, using Chandra data. We have compared the X-ray mass density profile with that derived from a dynamical analysis of the system's globular clusters (GCs). Gi...
Spectator fields and their imprints on the Cosmic Microwave Background: When a subdominant light scalar field ends slow roll during inflation, but well after the Hubble exit of the pivot scales, it may determine the cosmological perturbations. This thesis investigates how such a scalar field, the spectator, may leave i...
Two analytic relations connecting the hot gas astrophysics with the cold dark matter model for galaxy clusters: Galaxy clusters are good targets for examining our understanding of cosmology. Apart from numerical simulations and gravitational lensing, X-ray observation is the most common and conventional way to analyz...
Spectroscopic confirmation of two Lyman break galaxies at redshift beyond 7: We report the spectroscopic confirmation of two Lyman break galaxies at redshift > 7. The galaxies were observed as part of an ultra-deep spectroscopic campaign with FORS2 at the ESO/VLT for the confirmation of z~7 ``z--band dropout'' candid...
A roadmap to cosmological parameter analysis with third-order shear statistics I: Modelling and validation: In this work, which is the first of a series to prepare a cosmological parameter analysis with third-order cosmic shear statistics, we model both the shear three-point correlation functions $\Gamma^{(i)}$ and t...
Anisotropies of gravitational-wave standard sirens as a new cosmological probe without redshift information: Gravitational waves (GWs) from compact binary stars at cosmological distances are promising and powerful cosmological probes, referred to as the GW standard sirens. With future GW detectors, we will be able to...
Observational Limits on Type 1 AGN Accretion Rate in COSMOS: We present black hole masses and accretion rates for 182 Type 1 AGN in COSMOS. We estimate masses using the scaling relations for the broad Hb, MgII, and CIV emission lines in the redshift ranges 0.16<z<0.88, 1<z<2.4, and 2.7<z<4.9. We estimate the accretion ...
Studying the WHIM with Gamma Ray Bursts: We assess the possibility to detect and characterize the physical state of the missing baryons at low redshift by analyzing the X-ray absorption spectra of the Gamma Ray Burst [GRB] afterglows, measured by a micro calorimeters-based detector with 3 eV resolution and 1000 cm2 eff...
Domain Adaptive Graph Neural Networks for Constraining Cosmological Parameters Across Multiple Data Sets: Deep learning models have been shown to outperform methods that rely on summary statistics, like the power spectrum, in extracting information from complex cosmological data sets. However, due to differences in t...
Effects of a dark matter caustic passing through the Oort Cloud: We investigate the effect of a dark matter caustic passing through the Solar System. We find, confirming a previous result, that the Sun tracks the caustic surface for some time. We integrate numerically the equations of motion of the Sun and a comet for ...
Constraining stellar assembly and AGN feedback at the peak epoch of star formation: We study stellar assembly and feedback from active galactic nuclei (AGN) around the epoch of peak star formation (1<z<2), by comparing hydrodynamic simulations to rest-frame UV-optical galaxy colours from the Wide Field Camera 3 (WFC3...
Lemaitre-Tolman-Bondi cosmological models, smoothness, and positivity of the central deceleration parameter: We argued in a previous paper [R. A. Vanderveld et al. 2006, arXiv:astro-ph/0602476] that negative deceleration parameters at the center of symmetry in Lemaitre-Tolman-Bondi cosmological models can only occur ...
Non-tensorial Gravitational Wave Background in NANOGrav 12.5-Year Data Set: We perform the first search for an isotropic non-tensorial gravitational-wave background (GWB) allowed in general metric theories of gravity in the North American Nanohertz Observatory for Gravitational Waves (NANOGrav) 12.5-year data set. By...
Higgsless simulations of cosmological phase transitions and gravitational waves: First-order cosmological phase transitions in the early Universe source sound waves and, subsequently, a background of stochastic gravitational waves. Currently, predictions of these gravitational waves rely heavily on simulations of a H...
The Average Optical Spectra of Intense Starbursts at z~2: Outflows and the Pressurization of the ISM: An important property of star-forming galaxies at z~1-2 is the high local star-formation intensities they maintain over tens of kiloparsecs at levels that are only observed in the nearby Universe in the most powerful...
Dwarf galaxies in CDM and SIDM with baryons: observational probes of the nature of dark matter: We present the first cosmological simulations of dwarf galaxies, which include dark matter self-interactions and baryons. We study two dwarf galaxies within cold dark matter, and four different elastic self-interacting sce...
Reheating the Standard Model from a hidden sector: We consider a scenario where the inflaton decays to a hidden sector thermally decoupled from the visible Standard Model sector. A tiny portal coupling between the hidden and the visible sectors later heats the visible sector so that the Standard Model degrees of freedo...
Gravitational Waves from Broken Cosmic Strings: The Bursts and the Beads: We analyze the gravitational wave signatures of a network of metastable cosmic strings. We consider the case of cosmic string instability to breakage, with no primordial population of monopoles. This scenario is well motivated from GUT and string...
Cosmic Voids in Sloan Digital Sky Survey Data Release 7: We study the distribution of cosmic voids and void galaxies using Sloan Digital Sky Survey Data Release 7 (SDSS DR7). Using the VoidFinder algorithm as described by Hoyle 2002, we identify 1054 statistically significant voids in the northern galactic hemisphere w...
Effect of supersonic relative motion between baryons and dark matter on collapsed objects: Great attention is given to the first star formation and the epoch of reionization as main targets of planned large radio interferometries (e.g. Square Kilometre Array). Recently, it is claimed that the supersonic relative velo...
Glass-Like Random Catalogues for Two-Point Estimates on the Light Cone: We introduce grlic, a publicly available Python tool for generating glass-like point distributions with a radial density profile $n(r)$ as it is observed in large-scale surveys of galaxy distributions on the past light cone. Utilising these glass-l...
Generic 3-point Statistics with Tensor Modes in Light of Swampland and TCC: Recently proposed Swampland Criteria (SC) and Trans-Planckian Censorship Conjecture (TCC) together put stringent theoretical constraints on slow roll inflation, raising a question on future prospects of detection of Primordial Gravitational W...
Overcoming real-world obstacles in 21 cm power spectrum estimation: A method demonstration and results from early Murchison Widefield Array data: We present techniques for bridging the gap between idealized inverse covariance weighted quadratic estimation of 21 cm power spectra and the real-world challenges presented...
Cosmological constraints from the EFT power spectrum and tree-level bispectrum of 21cm intensity maps: We explore the information content of 21cm intensity maps in redshift space using the 1-loop Effective Field Theory power spectrum model and the bispectrum at tree level. The 21cm signal contains signatures of dark ...
IGM damping wing constraints on reionisation from covariance reconstruction of two $z\gtrsim7$ QSOs: Bright, high redshift ($z>6$) QSOs are powerful probes of the ionisation state of the intervening intergalactic medium (IGM). The detection of Ly$\alpha$ damping wing absorption imprinted in the spectrum of high-z QSO...
The thawing dark energy dynamics: Can we detect it?: We consider different classes of scalar field models including quintessence, and tachyon scalar fields with a variety of generic potential belonging to thawing type. Assuming the scalar field is initially frozen at $w=-1$, we evolve the system until the present time....
Science with the space-based interferometer eLISA. II: Gravitational waves from cosmological phase transitions: We investigate the potential for the eLISA space-based interferometer to detect the stochastic gravitational wave background produced by strong first-order cosmological phase transitions. We discuss the res...
On The Depolarization Asymmetry Seen in Giant Radio Lobes: The depolarization asymmetry seen in double-lobed radio sources, referred to as the Laing-Garrington (L-G) effect where more rapid depolarization is seen in the lobe with no visible jet as the wavelength increases, can be explained either by internal difference...
The Morphology of the Thermal Sunyaev-Zel'dovich Sky: At high angular frequencies the thermal Sunyaev-Zel'dovich (tSZ) effect constitutes the dominant signal in the CMB sky. The tSZ effect is caused by large scale pressure fluctuations in the baryonic distribution in the Universe so its statistical properties provide e...
Explaining low l anomalies in the CMB power spectrum with resonant superstring excitations during inflation: We explore the possibility that both the suppression of the $\ell = 2$ multipole moment of the power spectrum of cosmic microwave background temperature fluctuations and the possible dip for $\ell = 10-30$ can...
MACSJ1423.8+2404: Gravitational Lensing by a Massive, Relaxed Cluster of Galaxies at z=0.54: We present results of a gravitational-lensing and optical study of MACS ,J1423.8+2404 (z=0.545, MACS, J1423). Our analysis uses high-resolution images taken with the Hubble Space Telescope in the F555W and F814W passbands, gr...
Stringent neutrino flux constraints on anti-quark nugget dark matter: Strongly-interacting matter in the form of nuggets of nuclear-density material are not currently excluded as dark matter candidates in the ten gram to hundred kiloton mass range. A recent variation on quark nugget dark matter models postulates that a...
The impact of baryonic potentials on the gravothermal evolution of self-interacting dark matter haloes: The presence of a central baryonic potential can have a significant impact on the gravothermal evolution of self-interacting dark matter (SIDM) haloes. We extend a semi-analytical fluid model to incorporate the inf...
Planck pre-launch status: High Frequency Instrument polarization calibration: The High Frequency Instrument of Planck will map the entire sky in the millimeter and sub-millimeter domain from 100 to 857 GHz with unprecedented sensitivity to polarization ($\Delta P/T_{\tiny cmb} \sim 4\cdot 10^{-6}$) at 100, 143, 217 a...
Simulations of galaxy cluster mergers with velocity-dependent, rare and frequent self-interactions: Self-interacting dark matter (SIDM) has been proposed to solve small-scale problems in $\Lambda$CDM cosmology. In previous work, constraints on the self-interaction cross-section of dark matter have been derived assumi...
Astrophysical Plasma Instabilities induced by Long-Range Interacting Dark Matter: If dark matter (DM) is millicharged or darkly charged, collective plasma processes may dominate momentum exchange over direct particle collisions. Plasma streaming instabilities can couple the momentum of the DM to counter-streaming bar...
Mirror matter can alleviate the cosmological lithium problem: The abundance of lithium-7 confronts cosmology with a long lasting problem between the predictions of standard big bang nucleosynthesis and the baryonic density determined from the cosmic microwave background observations. This article investigates the influ...
KiDS-1000 Cosmology: Multi-probe weak gravitational lensing and spectroscopic galaxy clustering constraints: We present a joint cosmological analysis of weak gravitational lensing observations from the Kilo-Degree Survey (KiDS-1000), with redshift-space galaxy clustering observations from the Baryon Oscillation Spect...
Hi intensity mapping with MeerKAT: Primary beam effects on foreground cleaning: Upcoming and future neutral hydrogen Intensity Mapping surveys offer a great opportunity to constrain cosmology in the post-reionization Universe, provided a good accuracy is achieved in the separation between the strong foregrounds and t...
Primordial density and BAO reconstruction: We present a new method to reconstruct the primordial (linear) density field using the estimated nonlinear displacement field. The divergence of the displacement field gives the reconstructed density field. We solve the nonlinear displacement field in the 1D cosmology and show...
On the dynamics of a dark sector coupling: Interacting dark energy models may play a crucial role in explaining several important observational issues in modern cosmology and also may provide a solution to current cosmological tensions. Since the phenomenology of the dark sector could be extremely rich, one should not ...
$Λ$CDM Tensions: Localising Missing Physics through Consistency Checks: $\Lambda$CDM tensions are by definition model dependent; one sees anomalies through the prism of $\Lambda$CDM. Thus, progress towards tension resolution necessitates checking the consistency of the $\Lambda$CDM model to localise missing physics e...
Large-scale periodicity in the distribution of QSO absorption-line systems: The spatial-temporal distribution of absorption-line systems (ALSs) observed in QSO spectra within the cosmological redshift interval z = 0.0--4.3 is investigated on the base of our updated catalog of absorption systems. We consider so called...
The blue UV slopes of z~4 Lyman break galaxies: implications for the corrected star formation rate density: We plan to analyse dust extinction in Lyman Break Galaxies (LBGs) by introducing a new and more reliable approach to their selection and to the characterization of their distribution of UV slopes beta, using de...
NGC 2207/IC 2163: A Grazing Encounter with Large Scale Shocks: Radio continuum, Spitzer infrared, optical and XMM-Newton X-ray and UVM2 observations are used to study large-scale shock fronts, young star complexes, and the galactic nuclei in the interacting galaxies NGC 2207/IC 2163. There are two types of large-scale ...
Constraints on the mass-richness relation from the abundance and weak lensing of SDSS clusters: We constrain the scaling relation between optical richness ($\lambda$) and halo mass ($M$) for a sample of SDSS redMaPPer galaxy clusters within the context of the {\it Planck} cosmological model. We use a forward modeling...
Radio-Quiet AGN and the Transient Radio Sky: 8.4-GHZ radio imaging study of an optically selected sample of early type Seyfert galaxies; comparison of images taken at two epochs reveals possible variation in the nuclear radio flux density in five of them over a seven year period. It is shown that there is a possible co...
The Entrainment-Limited Evolution of FR II Sources: Maximum Sizes and A Possible Connection to FR Is: We construct a simple theoretical model to investigate how entrainment gradually erodes high-speed FR II jets. This process is described by embedding a mixing-layer model developed originally to describe FR I objects...
Bias in apparent dispersion measure due to de-magnification of plasma lensing on background radio sources: The effect of ionized gas on the propagation of radio signals is known as plasma lensing. Unlike gravitational lensing, plasma lensing causes both magnification and strong de-magnification effects to background ...
Type II Cepheids as Extragalactic Distance Candles: Extragalactic Type II Cepheids are tentatively identified in photometric surveys of IC 1613, M33, M101, M106, M31, NGC 4603, and the SMC. Preliminary results suggest that Type II Cepheids may play an important role as standard candles, in constraining the effects of m...
Constraining the halo mass function with observations: The abundances of dark matter halos in the universe are described by the halo mass function (HMF). It enters most cosmological analyses and parametrizes how the linear growth of primordial perturbations is connected to these abundances. Interestingly, this connecti...
Simulations of the merging galaxy cluster Abell 3376: Observed galaxy clusters often exhibit X-ray morphologies suggestive of recent interaction with an infalling subcluster. Abell 3376 is a nearby (z=0.046) massive galaxy cluster whose bullet-shaped X-ray emission indicates that it may have undergone a recent collisio...
Tensions in the dark: shedding light on Dark Matter-Dark Energy interactions: The emergence of an increasingly strong tension between the Hubble rate inferred from early- and late-time observations has reinvigorated interest in nonstandard scenarios, with the aim of reconciling these measurements. One such model invo...
Discovery of the first giant double radio relic in a galaxy cluster found in the PLANCK Sunyaev-Zel'dovich cluster survey: PLCK G287.0+32.9: We report the discovery of large scale diffuse non-thermal radio emission in PLCK G287.0+32.9, an exceptionally hot (T ~ 13 keV), massive and luminous galaxy cluster, strongly d...
Growing Massive Black Hole Pairs in Minor Mergers of Disk Galaxies: We perform a suite of high-resolution smoothed particle hydrodynamics simulations to investigate the orbital decay and mass evolution of massive black hole (MBH) pairs down to scales of ~30 pc during minor mergers of disk galaxies. Our simulation set i...
Reducing the $H_0$ and $σ_8$ tensions with Dark Matter-neutrino interactions: The introduction of Dark Matter-neutrino interactions modifies the Cosmic Microwave Background (CMB) angular power spectrum at all scales, thus affecting the reconstruction of the cosmological parameters. Such interactions can lead to a sli...
Nonparametric Dark Energy Reconstruction from Supernova Data: Understanding the origin of the accelerated expansion of the Universe poses one of the greatest challenges in physics today. Lacking a compelling fundamental theory to test, observational efforts are targeted at a better characterization of the underlying ca...
Mesoscopic Energy Ranking Constraints in the IllustrisTNG Simulations: We revisited the problem of mixing in a gravitational N-body system from the point of view of the ordering of coarse-grained cells in the one-particle energy space, here denoted {\it energy ranking preservation} (ERP). This effect has been noted for...
Constraining dark matter annihilation with the isotropic $γ$-ray background: updated limits and future potential: The nature of the Isotropic $\gamma$-ray Background (IGRB) measured by the Large Area Telescope (LAT) on the Fermi $\gamma$-ray space Telescope ({\it Fermi}) remains partially unexplained. Non-negligible ...
Broken scale invariance, $α$-attractors and vector impurity: We show that if the $\alpha$-attractor model is realized by the spontaneous breaking of the scale symmetry, then the stability and the dynamics of the vector field that gauges the scale symmetry can severely constrain the $\alpha$-parameter as $5/6 < \alpha <...
Probing the anisotropic local universe and beyond with SNe Ia data: The question of the transition to global isotropy from our anisotropic local Universe is studied using the Union 2 catalogue of Type Ia supernovae (SNe Ia). We construct a "residual" statistic sensitive to systematic shifts in their brightness in diffe...
Cosmic rays in galaxy clusters and their non-thermal emission: Radio observations prove the existence of relativistic particles and magnetic field associated with the intra-cluster-medium (ICM) through the presence of extended synchrotron emission in the form of radio halos and peripheral relics. This observational evi...
Multiple measurements of gravitational waves acting as standard probes: model-independent constraints on the cosmic curvature with DECIGO: Although the spatial curvature has been precisely determined via the cosmic microwave background (CMB) observation by Planck satellite, it still suffers from the well-known cosmic...
Degeneracies in parametrized modified gravity models: We study degeneracies between parameters in some of the widely used parametrized modified gravity models. We investigate how different observables from a future photometric weak lensing survey such as LSST, correlate the effects of these parameters and to what exten...
Dark Matter 2014: This article gives an overview on the status of experimental searches for dark matter at the end of 2014. The main focus is on direct searches for weakly interacting massive particles (WIMPs) using underground-based low-background detectors, especially on the new results published in 2014. WIMPs are e...
The Extended Optical Disk of M101: We have used deep, wide-field optical imaging to study the faint outskirts of the luminous spiral galaxy M101 (NGC 5457), as well as its surrounding environment. Over six square degrees, our imaging has a limiting surface brightness of mu_B ~ 29.5 mag/arcsec^2, and has revealed the st...
Astrophysical hydrodynamics with a high-order discontinuous Galerkin scheme and adaptive mesh refinement: Solving the Euler equations of ideal hydrodynamics as accurately and efficiently as possible is a key requirement in many astrophysical simulations. It is therefore important to continuously advance the numerical...
The shape of CMB temperature and polarization peaks on the sphere: We present a theoretical study of CMB temperature peaks, including its effect over the polarization field, and allowing nonzero eccentricity. The formalism is developed in harmonic space and using the covariant derivative on the sphere, which guarantees...
Supermassive black hole formation by the cold accretion shocks in the first galaxies: We propose a new scenario for supermassive star (SMS;>10^5Msun) formation in shocked regions of colliding cold accretion flows near the centers of first galaxies. Recent numerical simulations indicate that assembly of a typical firs...
Weak lensing from self-ordering scalar fields: Cosmological defects result from cosmological phase transitions in the early Universe and the dynamics reflects their symmetry-breaking mechanisms. These cosmological defects may be probed through weak lensing effects because they interact with ordinary matters only throug...
Observational evidence of fractality in the large-scale distribution of galaxies: Using a sample of 133 991 galaxies distributed in the sky region $100^{\circ} <\alpha<270^{\circ}$ and $7^{\circ}<\delta<65^{\circ}$, extracted from the SDSS NASA/AMES Value Added Galaxy Catalog (AMES-VAGC), we estimate the fractal dime...
Luminous Infrared Galaxies with the Submillimeter Array: II. Comparing the CO(3-2) Sizes and Luminosities of Local and High-Redshift Luminous Infrared Galaxies: We present a detailed comparison of the CO(3-2) emitting molecular gas between a local sample of luminous infrared galaxies (U/LIRGs) and a high redshift s...
The SEDs, Host Galaxies and Environments of Variability Selected AGN in GOODS-S: Variability selection has been proposed as a powerful tool for identifying both low-luminosity AGN and those with unusual SEDs. However, a systematic study of sources selected in such a way has been lacking. In this paper, we present the...
MAGIC observations and multiwavelength properties of the quasar 3C279 in 2007 and 2009: Context. 3C 279, the first quasar discovered to emit VHE gamma-rays by the MAGIC telescope in 2006, was reobserved by MAGIC in January 2007 during a major optical flare and from December 2008 to April 2009 following an alert from ...
Parameterizing scalar-tensor theories for cosmological probes: We study the evolution of density perturbations for a class of $f(R)$ models which closely mimic $\Lambda$CDM background cosmology. Using the quasi-static approximation, and the fact that these models are equivalent to scalar-tensor gravity, we write the mo...
Initial Results from the Nobeyama Molecular Gas Observations of Distant Bright Galaxies: We present initial results from the CO survey toward high redshift galaxies using the Nobeyama 45m telescope. Using the new wide bandwidth spectrometer equipped with a two-beam SIS receiver, we have robust new detections of three...
New Developments in Spiral Structure Theory: After a short review of the principal theories of spiral structure in galaxies, I describe two new developments. First, it now seems clear that linear theory cannot yield a full description for the development of spiral patterns because N-body simulations suggest that non-li...
Window function dependence of the novel mass function of primordial black holes: We investigate the ambiguity of the novel mass function of primordial black holes, which has succeeded in identifying the black hole mass in a given configuration of fluctuations, due to the choice of window function of smoothed density ...
How informative are summaries of the cosmic 21-cm signal?: The cosmic 21-cm signal will bring data-driven advances to studies of the Cosmic Dawn (CD) and Epoch of Reionization (EoR). Radio telescopes such as the SKA will eventually map the HI fluctuations over the first billion years - the majority of our observable Un...
Crab nebula at 260 GHz with the NIKA2 polarimeter. Implications for the polarization angle calibration of future CMB experiments: The quest for primordial gravitational waves enclosed in the Cosmic Microwave Background (CMB) polarization B-modes signal motivates the development of a new generation of high sensitive e...
Homogeneity and isotropy in the 2MASS Photometric Redshift catalogue: Using the 2MASS Photometric Redshift catalogue we perform a number of statistical tests aimed at detecting possible departures from statistical homogeneity and isotropy in the large-scale structure of the Universe. Making use of the angular homogenei...
Morphological Annotations for Groups in the FIRST Database: The morphology of selected groups of sources in the FIRST (Faint Images of the Radio Sky at Twenty Centimeters) survey and catalog is examined. Sources in the FIRST catalog (April 2003 release, 811117 entries) were sorted into singles, doubles, triples and gro...
Two New Catalogues of Superclusters of Abell/ACO Galaxy Clusters out to redshift 0.15: We present two new catalogues of superclusters of galaxies out to a redshit of z = 0.15, based on the Abell/ACO cluster redshift compilation maintained by one of us (HA). The first of these catalogues, the all-sky Main SuperCluster...
A fast and accurate method to compute the mass return from multiple stellar populations: The mass returned to the ambient medium by aging stellar populations over cosmological times sums up to a significant fraction (20% - 30% or more) of their initial mass. This continuous mass injection plays a fundamental role in ...
HI as a Probe of the Large Scale Structure in the Post-Reionization Universe: Visibility Correlations and Prospects for Detection: Simulated maps of the HI distribution in the post-reionization era are used to study the prospects for detection with existing and upcoming radio telescopes. We consider detection in the ...
AGN Feedback Driven Molecular Outflow in NGC 1266: NGC 1266 is a nearby field galaxy observed as part of the ATLAS3D survey (Cappellari et al. 2011). NGC 1266 has been shown to host a compact (< 200 pc) molecular disk and a mass-loaded molecular outflow driven by the AGN (Alatalo et al. 2011). Very Long Basline Array (...
Shapes and alignments of dark matter haloes and their brightest cluster galaxies in 39 strong lensing clusters: We study shapes and alignments of 45 dark matter (DM) haloes and their brightest cluster galaxies (BCGs) using a sample of 39 massive clusters from Hubble Frontier Field (HFF), Cluster Lensing And Supernova...
Cold gas in the inner regions of intermediate redshift clusters: Determining gas content and star formation rate has known remarkable progress in field galaxies, but has been much less investigated in galaxies inside clusters. We present the first CO observations of luminous infrared galaxies (LIRGs) inside the virial ...
Resolving the Far-IR Line Deficit: Photoelectric Heating and Far-IR Line Cooling in NGC 1097 and NGC 4559: The physical state of interstellar gas and dust is dependent on the processes which heat and cool this medium. To probe heating and cooling of the ISM over a large range of infrared surface brightness, on sub-ki...
Far-infrared Fine-Structure Line Diagnostics of Ultraluminous Infrared Galaxies: We present Herschel observations of six fine-structure lines in 25 Ultraluminous Infrared Galaxies at z<0.27. The lines, [O III]52, [N III]57, [O I]63, [N II]122, [O I]145, and [C II]158, are mostly single gaussians with widths <600 km s...
The clustering of massive Primordial Black Holes as Dark Matter: measuring their mass distribution with Advanced LIGO: The recent detection by Advanced LIGO of gravitational waves (GW) from the merging of a binary black hole system sets new limits on the merging rates of massive primordial black holes (PBH) that coul...
FIR/submm spectroscopy with Herschel: first results from the VNGS and H-ATLAS surveys: The FIR/submm window is one of the least-studied regions of the electromagnetic spectrum, yet this wavelength range is absolutely crucial for understanding the physical processes and properties of the ISM in galaxies. The advent of...
Lyman-alpha Emission From Cosmic Structure I: Fluorescence: We present predictions for the fluorescent Lyman-alpha emission signature arising from photoionized, optically thick structures in Smoothed Particle Hydrodynamic (SPH) cosmological simulations of a Lambda-CDM universe using a Monte Carlo Lyman-alpha radiative ...
The ages of stellar populations in a warm dark matter universe: By means of a semi-analytic model of galaxy formation, we show how the local observed relation between age and galactic stellar mass is affected by assuming a DM power spectrum with a small-scale cutoff. We compare results obtained by means of both a Lambd...
Detection of the Missing Baryons toward the Sightline of H1821+643: Based on constraints from Big Bang nucleosynthesis and the cosmic microwave background, the baryon content of the high-redshift Universe can be precisely determined. However, at low redshift, about one-third of the baryons remain unaccounted for, which...
Detecting relic gravitational waves in the CMB: Comparison of different methods: In this paper, we discuss the constraint on the relic gravitational waves by both temperature and polarization anisotropies power spectra of cosmic microwave background radiation. Taking into account the instrumental noises of Planck sat...
Radius-Dependent Spin Transition of Dark Matter Halos: A numerical detection of the radius-dependent spin transition of dark matter halos is reported. Analyzing the data from the IllustrisTNG simulations, we measure the halo spin vectors at several inner radii within the virial boundaries and investigate their orientat...
First detection of a virial shock with SZ data: implication for the mass accretion rate of Abell 2319: Shocks produced by the accretion of infalling gas in the outskirt of galaxy clusters are expected in the hierarchical structure formation scenario, as found in cosmological hydrodynamical simulations. Here, we repor...
Neural networks and standard cosmography with newly calibrated high redshift GRB observations: Gamma-ray bursts (GRBs) detected at high redshift can be used to trace the cosmic expansion history. However, the calibration of their luminosity distances is not an easy task in comparison to Type Ia Supernovae (SNeIa). To...
Exploring Evaporating Primordial Black Holes with Gravitational Waves: Primordial black holes (PBHs) from the early Universe have been connected with the nature of dark matter and can significantly affect cosmological history. We show that coincidence dark radiation and density fluctuation gravitational wave signatures...