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Studying neutral hydrogen structures during the epoch of reionization using fractal dimensions: Fractal dimensions can be used to characterize the clustering and lacunarities in density distributions. We use generalized fractal dimensions to study the neutral hydrogen distribution (HI) during the epoch of reionizatio...
Bound on the graviton mass from Chandra X-ray cluster sample: We present new limits on the graviton mass using a sample of 12 relaxed galaxy clusters, for which temperature and gas density profiles were derived by Vikhlinin et al (astro-ph/0507092) using Chandra X-ray observations. These limits can be converted to a bo...
How to calculate dark matter direct detection exclusion limits that are consistent with gamma rays from annihilation in the Milky Way halo: When comparing constraints on the Weakly Interacting Massive Particle (WIMP) properties from direct and indirect detection experiments it is crucial that the assumptions made abo...
Lyman alpha Radiative Transfer with Dust: Escape Fractions from Simulated High-Redshift Galaxies: The Lyman alpha emission line is an essential diagnostic tool for probing galaxy formation and evolution. Not only is it commonly the strongest observable line from high-redshift galaxies but from its shape detailed info...
The Milky Way rotation curve in Horava - Lifshitz theory: The Horava - Lifshitz (HL) theory has recently attracted a lot of interest as a viable solution to some quantum gravity related problems and the presence of an effective cosmological constant able to drive the cosmic speed up. We show here that, in the weak fiel...
The Non-Linear Fisher Information content of cosmic shear surveys: We quantify the Fisher information content of the cosmic shear survey two-point function as a function of noise and resolution. The two point information of dark matter saturates at the trans-linear scale. We investigate the impact of non-linear non-Gau...
Standardizing reverberation-measured C IV time-lag quasars, and using them with standardized Mg II quasars to constrain cosmological parameters: We use 38 C IV quasar (QSO) reverberation-mapped (RM) observations, which span eight orders of magnitude in luminosity and the redshift range $0.001064 \leq z \leq 3.368$, t...
Chameleon Field Theories: Chameleons are light scalar fields with remarkable properties. Through the interplay of self-interactions and coupling to matter, chameleon particles have a mass that depends on the ambient matter density. The manifestation of the fifth force mediated by chameleons therefore depends sensitivel...
Discriminating Topology in Galaxy Distributions using Network Analysis: (abridged) The large-scale distribution of galaxies is generally analyzed using the two-point correlation function. However, this statistic does not capture the topology of the distribution, and it is necessary to resort to higher order correlation...
3D Reconstruction of the Density Field: An SVD Approach to Weak Lensing Tomography: We present a new method for constructing three-dimensional mass maps from gravitational lensing shear data. We solve the lensing inversion problem using truncation of singular values (within the context of generalized least squares es...
The Two-Phase, Two-Velocity Ionized Absorber in the Seyfert 1 Galaxy NGC 5548: We present an analysis of X-ray high quality grating spectra of the Seyfert 1 galaxy NGC 5548 using archival Chandra HETGS and LETGS observations for a total exposure time of 800ks. The continuum emission is well represented by a powerlaw ...
The clustering of the SDSS-IV extended Baryon Oscillation Spectroscopic Survey DR16 luminous red galaxy and emission line galaxy samples: cosmic distance and structure growth measurements using multiple tracers in configuration space: We perform a multi-tracer analysis using the complete Sloan Digital Sky Survey ...
Improved model-independent constraints on the recombination era and development of a direct projection method: The precision of recent experiments such as ${\it Planck}$ have allowed us to constrain standard and non-standard physics (e.g., due to dark matter annihilation or varying fundamental constants) during the r...
Galactic winds and stellar populations in Lyman $α$ emitting galaxies at z ~ 3.1: We present a sample of 33 spectroscopically confirmed z ~ 3.1 Ly$\alpha$-emitting galaxies (LAEs) in the Cosmological Evolution Survey (COSMOS) field. This paper details the narrow-band survey we conducted to detect the LAE sample, the ...
Constraining dark energy fluctuations with supernova correlations: We investigate constraints on dark energy fluctuations using type Ia supernovae. If dark energy is not in the form of a cosmological constant, that is if the equation of state is not equal to -1, we expect not only temporal, but also spatial variations ...
Time delay between images of the lensed quasar UM673: We study brightness variations in the double lensed quasar UM673 (Q0142-100) with the aim of measuring the time delay between its two images. In the paper we combine our previously published observational data of UM673 obtained during the 2003 - 2005 seasons at the ...
Shock Waves and Cosmic Ray Acceleration in the Outskirts of Galaxy Clusters: The outskirts of galaxy clusters are continuously disturbed by mergers and gas infall along filaments, which in turn induce turbulent flow motions and shock waves. We examine the properties of shocks that form within $r_{200}$ in sample gala...
Constraints on Primordial non-Gaussianity from Future HI Intensity Mapping Experiments: The primordial non-Gaussianity induces scale-dependent bias of the \hi with respect to the underlying dark matter, which exhibits features on the very large scales of the 21-cm power spectrum potentially observable with \hi intens...
Gamma-Ray Burst Afterglows as Analogues of High Frequency-Peaked BL Lac Objects: The spectral properties from radio to optical bands are compared between the 18 optically bright Gamma-ray burst afterglows and well established power-spectrum sequence in Blazars. The comparison shows that the afterglows are well agreem...
Obscured star-formation and environment in the COSMOS field: We investigate the effects of the environment on star-formation in a sample of massive luminous and ultra-luminous infrared galaxies (LIRGs and ULIRGs) with S(24 micron)>80 uJy and i+<24 in the COSMOS field. We exploit the accurate photometric redshifts in CO...
The X-ray invisible Universe. A look into the halos undetected by eROSITA: The paper presents the analysis of optically selected GAMA groups and clusters in the SRG/eROSITA X-ray map of eFEDS (eROSITA Final Equatorial Depth Survey), in the halo mass range $10^{13}-5{\times}10^{14}$ $M_{\odot}$ and at $z < 0.2$. All X...
Nonhelical turbulence and the inverse transfer of energy: A parameter study: We explore the phenomenon of the recently discovered inverse transfer of energy from small to large scales in decaying magnetohydrodynamical turbulence by Brandenburg et al. (2015) even for nonhelical magnetic fields. For this investigation ...
Deep learning dark matter map reconstructions from DES SV weak lensing data: We present the first reconstruction of dark matter maps from weak lensing observational data using deep learning. We train a convolution neural network (CNN) with a Unet based architecture on over $3.6\times10^5$ simulated data realizations ...
Hubble Diagram Dispersion From Large-Scale Structure: We consider the effects of large structures in the Universe on the Hubble diagram. This problem is treated non-linearly by considering a Swiss Cheese model of the Universe in which under-dense voids are represented as negatively curved regions of space-time. Exact e...
Constraints on the Nambu-Goto cosmic string contribution to the CMB power spectrum in light of new temperature and polarisation data: Cosmic strings generate vector and tensor modes in the B-channel of polarization, as well as the usual temperature power spectrum and E-mode polarization spectrum. We use the power spe...
The (not so) squeezed limit of the primordial 3-point function: We prove that, in a generic single-field model, the consistency relation for the 3-point function in the squeezed limit receives corrections that vanish quadratically in the ratio of the momenta, i.e. as (k_L/k_S)^2. This implies that a detection of a bisp...
The Thermal Sunyaev-Zel'dovich Effect from Massive, Quiescent 0.5 $\leq$ z $\leq$ 1.5 Galaxies: We use combined South Pole Telescope (SPT)+Planck temperature maps to analyze the circumgalactic medium (CGM) encompassing 138,235 massive, quiescent 0.5 $\leq$ z $\leq$ 1.5 galaxies selected from data from the Dark Energy...
The spin of late-type galaxies at redshifts z < 1.2: We study the evolution of the galactic spin using data of high redshift galaxies in the fields of the Great Observatories Origins Deep Survey (GOODS). Through simple dynamical considerations we estimate the spin for the disc galaxies in our sample and find that its d...
Evolution of Cosmological Parameters and Fundamental Constants in a Flat Quintessence Cosmology: A Dynamical Alternative to ΛCDM: The primary purpose of this work is the provision of accurate, analytic, evolutionary templates for cosmological parameters and fundamental constants in a dynamical cosmology. A flat quint...
The WiggleZ Dark Energy Survey: Improved Distance Measurements to z = 1 with Reconstruction of the Baryonic Acoustic Feature: We present significant improvements in cosmic distance measurements from the WiggleZ Dark Energy Survey, achieved by applying the reconstruction of the baryonic acoustic feature technique. We ...
Population III Star Formation in Magnetized Primordial Clouds: The evolution of primordial collapsing clouds and formation of proto-Population III stars are investigated using three-dimensional ideal MHD simulation. We calculated the evolution of magnetized primordial clouds from the prestellar stage until the epoch af...
A novel PBH production mechanism from non-Abelian gauge fields during inflation: We consider the case of axion-like particles (ALPs) during inflation. When coupled to a non-Abelian gauge sector via a Chern-Simons term, ALPs support an intriguing, testable, phenomenology with very distinctive features including chiral...
Pure Gravitational Wave Estimation of Hubble's Constant using Neutron Star-Black Hole Mergers: Here we show how $H_0$ can be derived purely from the gravitational waves (GW) of neutron star-black hole (NSBH) mergers. This new method provides an estimate of $H_0$ spanning the redshift range, $z<0.25$ with current GW s...
The Relation between Nuclear Activity and Stellar Mass in Galaxies: The existence of correlations between nuclear properties of galaxies, such as the mass of their central black holes, and larger scale features, like the bulge mass and luminosity, represent a fundamental constraint on galaxy evolution. Although the act...
Suzaku Discovery of a Hard Component Varying Independently of the Power-Law Emission in MCG-6-30-15: Focusing on hard X-ray variability, we reanalyzed Suzaku data of Type I Seyfert galaxy MCG-6-30-15 obtained in 2006. Intensity-sorted spectroscopy and a principal component analysis consistently revealed a very hard c...
Review on non-directional direct dark matter searches: An overview of non-directional direct detection methods is given. The currently leading experiments for spin independent WIMPs interactions are using simultaneous measurement of two quantities for event-by-event background discrimination in cryogenic bolometers and...
How unusual is the cool-core radio halo cluster CL1821+643 ?: Massive galaxy clusters with cool-cores typically host diffuse radio sources called mini-haloes, whereas, those with non-cool-cores host radio haloes. We attempt to understand the unusual nature of the cool-core galaxy cluster CL1821+643 that hosts a Mpc-sca...
The SINS/zC-SINF survey of z~2 galaxy kinematics: Outflow properties: Based on SINFONI Ha, [NII] and [SII] AO data of 30 z \sim 2 star-forming galaxies (SFGs) from the SINS and zcSINF surveys, we find a strong correlation of the Ha broad flux fraction with the star formation surface density of the galaxy, with an appar...
Observability of Dark Matter Substructure with Pulsar Timing Correlations: Dark matter substructure on small scales is currently weakly constrained, and its study may shed light on the nature of the dark matter. In this work we study the gravitational effects of dark matter substructure on measured pulsar phases in p...
Planck 2015 results. XIII. Cosmological parameters: We present results based on full-mission Planck observations of temperature and polarization anisotropies of the CMB. These data are consistent with the six-parameter inflationary LCDM cosmology. From the Planck temperature and lensing data, for this cosmology we find...
Exponential growth of the number density of massive early-type galaxies: We determine the evolution of the co-moving density of the most massive ($M_* \geq 10^{12} M_\odot$) early-type galaxy population in the redshift range of $z = 0.15$ - 0.45 in different stellar mass ranges using data from the Sloan Digital Sky Sur...
Variable time flow as an alternative to dark energy: Time is a parameter playing a central role in our most fundamental modelling of natural laws. Relativity theory shows that the comparison of times measured by different clocks depends on their relative motions and on the strength of the gravitational field in which t...
Quasars probing intermediate redshift star-forming galaxies: We present a sample of 46 [OIII]-emitting galaxies at z<0.8 detected in the fibre spectra of quasars from the SDSS-DR7 through an automatic search procedure. We also detect [OII] and Hb emission lines from most of these galaxies in the SDSS spectra. We study ...
Cosmology today-A brief review: This is a brief review of the standard model of cosmology. We first introduce the FRW models and their flat solutions for energy fluids playing an important role in the dynamics at different epochs. We then introduce different cosmological lengths and some of their applications. The late...
The Imprint of The Extragalactic Background Light in the Gamma-Ray Spectra of Blazars: The light emitted by stars and accreting compact objects through the history of the Universe is encoded in the intensity of the extragalactic background light (EBL). Knowledge of the EBL is important to understand the nature of sta...
A Lyman alpha halo around a quasar at redshift z=6.4: We present long-slit spectroscopic data which reveals extended Lyman alpha emission around the z=6.417 radio-quiet quasar CFHQS J2329-0301. The Lyman alpha emission is extended over 15 kpc and has a luminosity of > 8 x 10^36 W, comparable to the most luminous Lyman ...
Careful calculation of thermodynamical functions of tachyon gas: We analyze several approaches to the thermodynamics of tachyon matter. The energy spectrum of tachyons $\epsilon_k=\sqrt{k^2-m^2}$ is defined at $k\geq m$ and it is not evident how to determine the tachyonic distribution function and calculate its thermod...
Cosmology with SKA Radio Continuum Surveys: Radio continuum surveys have, in the past, been of restricted use in cosmology. Most studies have concentrated on cross-correlations with the cosmic microwave background to detect the integrated Sachs-Wolfe effect, due to the large sky areas that can be surveyed. As we move i...
Major Merging: The Way to Make a Massive, Passive Galaxy: We analyze the projected axial ratio distribution, p(b/a), of galaxies that were spectroscopically selected from the Sloan Digital Sky Survey (DR6) to have low star-formation rates. For these quiescent galaxies we find a rather abrupt change in p(b/a) at a stell...
The Cosmic Microwave Background: The history of its experimental investigation and its significance for cosmology: This review describes the discovery of the cosmic microwave background radiation in 1965 and its impact on cosmology in the 50 years that followed. This discovery has established the Big Bang model of th...
Crossing $w=-1$ by a single scalar field coupling with matter and the observational constraints: Motivated by Yang-Mills dark energy model, we propose a new model by introducing a logarithmic correction. we find that this model can avoid the coincidence problem naturally and gives an equation of state $w$ smoothly cr...
Are Newly Discovered HI High Velocity Clouds Minihalos in the Local Group?: A set of HI sources extracted from the north Galactic polar region by the ongoing ALFALFA survey has properties that are consistent with the interpretation that they are associated with isolated minihalos in the outskirts of the Local Group (...
Current cosmological constraints on the curvature, dark energy and modified gravity: We apply the Union2 compilation of 557 supernova Ia data, the baryon acoustic oscillation measurement of distance, the cosmic microwave background radiation data from the seven year Wilkinson Microwave Anisotropy Probe, and the Hubbl...
Ionized Gas in the Irr Galaxy IC 10: The Emission Spectrum and Ionization Sources: We present the results of observations of the Irr galaxy IC 10 at the 6-m SAO telescope with the panoramic Multi-Pupil Fiber Spectrograph (MPFS). Based on the results of these observations and our long-slit spectroscopy performed previ...
X-ray emission from cosmic web filaments in SRG/eROSITA data: Using the publicly available eROSITA Final Equatorial Depth Survey (eFEDS) data, we detected the stacked X-ray emissions at the position of 463 filaments at a significance of 3.8 sigma based on the combination of all energy bands. In parallel, we found that ...
A cosmic microwave background search for fine-structure constant evolution: In some extensions of the standard model of particle physics, the values of the fundamental coupling constants vary in space and time. Some observations of quasars hint at time and spatial variation of the fine structure constant $\alpha$. He...
Weak-Lensing Mass Calibration of ACTPol Sunyaev-Zel'dovich Clusters with the Hyper Suprime-Cam Survey: We present weak-lensing measurements using the first-year data from the Hyper Suprime-Cam Strategic Survey Program on the Subaru telescope for eight galaxy clusters selected through their thermal Sunyaev-Zel'dovich ...
The sub-mm morphology of the interacting galaxy NGC 3627: We present sub-mm continuum and heterodyne data of the interacting galaxy NGC 3627, obtained with the HHT and APEX. We find significant changes in the molecular line ratios over small scales in the southeastern part of this galaxy. The kinematics of the CO(2-1) ...
Search for cold and hot gas in the ram pressure stripped Virgo dwarf galaxy IC3418: We present IRAM 30m sensitive upper limits on CO emission in the ram pressure stripped dwarf Virgo galaxy IC3418 and in a few positions covering HII regions in its prominent 17 kpc UV/Ha gas-stripped tail. In the central few arcsecond...
Large HI optical depth and Redshifted 21-cm signal from cosmic dawn: The HI 21-cm optical depth ($\tau_b$) can be considerably large as the kinetic and spin temperature of the inter-galactic medium (IGM) is expected to be very low during cosmic dawn. It will be particularly higher at regions with HI over-density. We re...
Galaxy cluster searches based on photometric redshifts in the four CFHTLS Wide fields: We have developed a method for detecting clusters in large imaging surveys, based on the detection of structures in galaxy density maps made in slices of photometric redshifts. This method was first applied to the Canada France Haw...
Blind correction of the EB-leakage in the pixel domain: We study the problem of EB-leakage that is associated with incomplete polarized CMB sky. In the blind case that assumes no additional information about the statistical properties and amplitudes of the signal from the missing sky region, we prove that the recycling...
Testing bound dark energy with cosmological parameter and fundamental constant evolution: A new bound dark energy, BDE, cosmology has been proposed where the dark energy is the binding energy between light meson fields that condense a few tens of years after the big bang. It is reported that the correct dark energy d...
Imaging Systematics and Clustering of DESI Main Targets: We evaluate the impact of imaging systematics on the clustering of luminous red galaxies (LRG), emission-line galaxies (ELG) and quasars (QSO) targeted for the upcoming Dark Energy Spectroscopic Instrument (DESI) survey. Using Data Release 7 of the DECam Legacy S...
Modeling The GRB Host Galaxy Mass Distribution: Are GRBs Unbiased Tracers of Star Formation?: We model the mass distribution of long gamma-ray burst (GRB) host galaxies given recent results suggesting that GRBs occur in low metallicity environments. By utilizing measurements of the redshift evolution of the mass-meta...
Round Table Discussion at the Workshop "New Directions in Modern Cosmology": The workshop "New directions in modern cosmology", organized by Theo Nieuwenhuizen, Rudy Schild, Francesco Sylos Labini and Ruth Durrer, was held from September 27 until October 1, 2010, in the Lorentz Center in Leiden, the Netherlands. A tr...
Abundance determination in HII regions from spectra without the [OII]3727+3729 line: We suggest an empirical calibration for determination of oxygen and nitrogen abundances and electron temperature in HII regions where the [OII]3727+3729 line (R_2) is not available. The calibration is based on the strong emission lin...
Fractal Dimension as a measure of the scale of Homogeneity: In the multi-fractal analysis of large scale matter distribution, the scale of transition to homogeneity is defined as the scale above which the fractal dimension of underlying point distribution is equal to the ambient dimension of the space in which points a...
Gaussian Process Regression for foreground removal in HI intensity mapping experiments: We apply for the first time Gaussian Process Regression (GPR) as a foreground removal technique in the context of single-dish, low redshift HI intensity mapping, and present an open-source Python toolkit for doing so. We use MeerK...
Rotation curves of rotating galactic BEC dark matter halos: We present the dynamics of rotating Bose Condensate galactic dark matter halos, made of an ultralight spinless boson. We restrict to the case of adding axisymmetric rigid rotation to initially spherically symmetric structures and show there are three regimes: ...
Gravitational Lens Recovery with GLASS: Measuring the mass profile and shape of a lens: We use a new non-parametric gravitational modelling tool -- \Glass{} -- to determine what quality of data (strong lensing, stellar kinematics, and/or stellar masses) are required to measure the circularly averaged mass profile of ...
Inflationary magnetogenesis with a self-consistent coupling function: In this paper, we discuss the inflationary magnetogenesis scenario, in which the coupling function is introduced to break the conformal invariance of electromagnetic action. Unlike in conventional models, we deduce the Maxwell's equations under the p...
Spectroscopic identification of a redshift 1.55 supernova host galaxy from the Subaru Deep Field Supernova Survey: Context: The Subaru Deep Field (SDF) Supernova Survey discovered 10 Type Ia supernovae (SNe Ia) in the redshift range 1.5<z<2.0, as determined solely from photometric redshifts of the host galaxies. Howe...
Effects of Lens Motion and Uneven Magnification on Image Spectra: Counter to intuition, the images of an extended galaxy lensed by a moving galaxy cluster should have slightly different spectra in any metric gravity theory. This is mainly for two reasons. One relies on the gravitational potential of a moving lens being...
On the radiative and thermodynamic properties of the Cosmic Microwave Background radiation using COBE FIRAS instrument data: Use formulas to describe the monopole and dipole spectra of the Cosmic Microwave Background (CMB) radiation, the exact expressions for the temperature dependences of the radiative and thermodyn...
Parity violation in the CMB bispectrum by a rolling pseudoscalar: We investigate parity-violating signatures of temperature and polarization bispectra of the cosmic microwave background (CMB) in an inflationary model where a rolling pseudoscalar produces large equilateral tensor non-Gaussianity. By a concrete computati...
The ALPINE-ALMA [CII] survey: Survey strategy, observations and sample properties of 118 star-forming galaxies at $4<z<6$: The ALMA-ALPINE [CII] survey is aimed at characterizing the properties of a sample of normal star-forming galaxies (SFGs). The ALMA Large Program to INvestigate (ALPINE) features 118 galaxies obs...
COSMOS weak-lensing constraints on modified gravity: The observed acceleration of the universe, explained through dark energy, could alternatively be explained through a modification of gravity that would also induce modifications in the evolution of cosmological perturbations. We use new weak lensing data from the COS...
Testing the assumptions of the Effective Field Theory of Large-Scale Structure: The Effective Field Theory of Large-Scale Structure (EFTofLSS) attempts to amend some of the shortcomings of the traditional perturbative methods used in cosmology. It models the evolution of long-wavelength perturbations above a cutoff s...
Galaxy clusters in local Universe simulations without density constraints: a long uphill struggle: Galaxy clusters are excellent cosmological probes provided that their formation and evolution within the large scale environment are precisely understood. Therefore studies with simulated galaxy clusters have flourished...
The Future of Primordial Black Holes: Open Questions and Roadmap: We discuss some of the the open questions and the roadmap in the physics of primordial black holes. Black holes are the only dark matter candidate that is known to actually exit. Their conjectured primordial role is admittedly based on hypothesis rather ...
New constraints on very light pseudoscalars: Nearly massless axion-like particles are of interest for astrophysical observations, and some constraints on their parameter space do exist in the literature. Here, we propose to put new constraints on these particles using polarisation and, in particular, the polarisation d...
Angular momentum - mass relation for dark matter haloes: We study the empirical relation between an astronomical object's angular momentum $J$ and mass $M$, $J=\beta M^\alpha$, the $J-M$ relation, using N-body simulations. In particular, we investigate the time evolution of the $J-M$ relation to study how the initial p...
Determining $H_0$ using a model-independent method: By using type Ia supernovae (SNIa) to provide the luminosity distance (LD) directly, which depends on the value of the Hubble constant $H_0= 100 h\; {\rm km\; s^{-1}\; Mpc^{-1}}$, and the angular diameter distance from galaxy clusters or baryon acoustic oscillations (...
CMB statistical anisotropies of classical and quantum origins: We examine the impact of different anisotropic relics on inflation, in particular the predictions on the density perturbations. These relics can be the source of the large scale anomalies in the cosmic microwave background. There are two different types of ...
Local Luminous Infrared Galaxies: Spatially resolved mid-infrared observations with Spitzer/IRS: Luminous Infrared (IR) Galaxies (LIRGs) are an important cosmological class of galaxies as they are the main contributors to the co-moving star formation rate density of the universe at z=1. In this paper we present a GTO...
Spatial Curvature Falsifies Eternal Inflation: Inflation creates large-scale cosmological density perturbations that are characterized by an isotropic, homogeneous, and Gaussian random distribution about a locally flat background. Even in a flat universe, the spatial curvature measured within one Hubble volume receives...
Limits on primordial magnetic fields from primordial black hole abundance: Primordial magnetic field (PMF) is one of the feasible candidates to explain observed large-scale magnetic fields, for example, intergalactic magnetic fields. We present a new mechanism that brings us information about PMFs on small scales bas...
A Dark Matter Superfluid: In this talk we present a novel framework that unifies the stunning success of MOND on galactic scales with the triumph of the LambdaCDM model on cosmological scales. This is achieved through the rich and well-studied physics of superfluidity. The dark matter and MOND components have a common ...
Direct detection of WIMPs : Implications of a self-consistent truncated isothermal model of the Milky Way's dark matter halo: Direct detection of Weakly Interacting Massive Particle (WIMP) candidates of Dark Matter (DM) is studied within the context of a self-consistent truncated isothermal model of the finite-size d...
The Balmer decrement of SDSS galaxies: High resolution spectra are necessary to distinguish and correctly measure the Balmer emission lines due to the presence of strong metal and Balmer absorption features in the stellar continuum. This accurate measurement is necessary for use in emission line diagnostics, such as th...
Testing spherical evolution for modelling void abundances: We compare analytical predictions of void volume functions to those measured from N-body simulations, detecting voids with the zobov void finder. We push to very small, nonlinear voids, below few Mpc radius, by considering the unsampled DM density field. We als...
From galactic bars to the Hubble tension: weighing up the astrophysical evidence for Milgromian gravity: Astronomical observations reveal a major deficiency in our understanding of physics $-$ the detectable mass is insufficient to explain the observed motions in a huge variety of systems given our current understand...
The evolution of clustering length, large-scale bias and host halo mass at 2<z<5 in the VIMOS Ultra Deep Survey (VUDS): We investigate the evolution of galaxy clustering for galaxies in the redshift range 2.0<$z$<5.0 using the VIMOS Ultra Deep Survey (VUDS). We present the projected (real-space) two-point correlation...
Ly alpha escape during cosmological hydrogen recombination: the 3d-1s and 3s-1s two-photon processes: We give a formulation of the radiative transfer equation for Lyman alpha photons which allows us to include the two-photon corrections for the 3s-1s and 3d-1s decay channels during cosmological hydrogen recombination...
Statistical effects of the observer's peculiar velocity on source number counts: The velocity of the Sun with respect to the cosmic microwave background (CMB) can be extracted from the CMB dipole, provided its intrinsic dipole is assumed to be small in comparison. This interpretation is consistent, within fairly larg...
On the Radio and Optical Luminosity Evolution of Quasars: We calculate simultaneously the radio and optical luminosity evolutions of quasars, and the distribution in radio loudness R defined as the ratio of radio and optical luminosities, using a flux limited data set containing 636 quasars with radio and optical fluxe...
Disentangling the gamma-ray emission of NGC1275 and that of the Perseus cluster: (Abridged). The gamma-ray emission from galaxy clusters hosting active galaxies is a complex combination of diffuse and point-like emission with different spectral and spatial properties. We discuss the case of the Perseus cluster contai...
Precision Tests of CO and [CII] Power Spectra Models against Simulated Intensity Maps: Line intensity mapping (LIM) is an emerging technique with a unique potential to probe a wide range of scales and redshifts. Realizing the full potential of LIM, however, relies on accurate modeling of the signal. We introduce an e...
Constraining the role of star cluster mergers in nuclear cluster formation: Simulations confront integral-field data: We present observations and dynamical models of the stellar nuclear clusters (NCs) at the centres of NGC 4244 and M33. We then compare these to an extensive set of simulations testing the importance o...
Carbon Detection in Early-Time Optical Spectra of Type Ia Supernovae: While O is often seen in spectra of Type Ia supernovae (SNe Ia) as both unburned fuel and a product of C burning, C is only occasionally seen at the earliest times, and it represents the most direct way of investigating primordial white dwarf materia...
Pulsar Timing Array Constraints on Primordial Black Holes with NANOGrav 11-Year Data Set: The detection of binary black hole coalescences by LIGO/Virgo has aroused the interest in primordial black holes (PBHs), because they could be both the progenitors of these black holes and a compelling candidate of dark matter (...
Toward unbiased estimations of the statefinder parameters: With the use of simulated supernova catalogs, we show that the statefinder parameters turn out to be poorly and biased estimated by standard cosmography. To this end, we compute their standard deviations and several bias statistics on cosmologies near the conco...
Testing for a large local void by investigating the Near-Infrared Galaxy Luminosity Function: Recent cosmological modeling efforts have shown that a local underdensity on scales of a few hundred Mpc (out to z ~ 0.1), could produce the apparent acceleration of the expansion of the universe observed via type Ia superno...
X-raying the Winds of Luminous Active Galaxies: We briefly describe some recent observational results, mainly at X-ray wavelengths, on the winds of luminous active galactic nuclei (AGNs). These winds likely play a significant role in galaxy feedback. Topics covered include (1) Relations between X-ray and UV absorption ...
On the relation between Seyfert 2 accretion rate and environment at z < 0.1: We analyse different properties of the small scale environment of Seyfert 2 for two samples selected according to the accretion rate parameter, R, from the DR7-SDSS survey. We compare the results with two control samples of non-active galaxi...
The Araucaria Project. Determination of the LMC Distance from Late-Type Eclipsing Binary Systems: I. OGLE-051019.64-685812.3: We have analyzed the double-lined eclipsing binary system OGLE-051019.64-685812.3 in the LMC which consists of two G4 giant components with very similar effective temperatures. A detailed anal...
The metal-enriched host of an energetic gamma-ray burst at z ~ 1.6: (Abridged) Long gamma-ray burst (GRB) host galaxies might open a short-cut to the characteristics of typical star-forming galaxies throughout the history of the Universe. Due to the absence of near-infrared (NIR) spectroscopy, however, detailed investi...
Validating estimates of the growth rate of structure with modified gravity simulations: We perform a validation of estimates of the growth rate of structure, described by the parameter combination $f\sigma_8$, in modified gravity cosmologies. We consider an analysis pipeline based on the redshift-space distortion mod...
Hubble Space Telescope Observations of Mira Variables in the Type Ia Supernova Host NGC 1559: An Alternative Candle to Measure the Hubble Constant: We present year-long, near-infrared Hubble Space Telescope WFC3 observations used to search for Mira variables in NGC 1559, the host galaxy of the Type Ia supernova (SN I...
The Herschel Stripe 82 Survey (HerS): Maps and Early Catalog: We present the first set of maps and band-merged catalog from the Herschel Stripe 82 Survey (HerS). Observations at 250, 350, and 500 micron were taken with the Spectral and Photometric Imaging Receiver (SPIRE) instrument aboard the Herschel Space Observator...
Scattered Emission from z~1 Galactic Outflows: Mapping Mg II resonance emission scattered by galactic winds offers a means to determine the spatial extent and density of the warm outflow. Using Keck/LRIS spectroscopy, we have resolved scattered Mg II emission to the east of 32016857, a star-forming galaxy at z =0.9392 ...
Unscreening Modified Gravity in the Matter Power Spectrum: Viable modifications of gravity that may produce cosmic acceleration need to be screened in high-density regions such as the Solar System, where general relativity is well tested. Screening mechanisms also prevent strong anomalies in the large-scale structure a...
The extended ROSAT-ESO Flux-Limited X-ray Galaxy Cluster Survey (REFLEX II) V. Exploring a local underdensity in the Southern Sky: Several claims have been made that we are located in a locally underdense region of the Universe based on observations of supernovae and galaxy density distributions. Two recent studies o...
Time-Delay Cosmography: Measuring the Hubble Constant and other cosmological parameters with strong gravitational lensing: Multiply lensed sources experience a relative time delay in the arrival of photons. This effect can be used to measure absolute distances and the Hubble constant ($H_0$) and is known as time-dela...
How cold is Dark Matter? Constraints from Milky Way Satellites: We test the luminosity function of Milky Way satellites as a constraint for the nature of Dark Matter particles. We perform dissipationless high-resolution N-body simulations of the evolution of Galaxy-sized halo in the standard Cold Dark Matter (CDM) mode...
ALFALFA HI Data Stacking II. HI content of the host galaxies of AGN: We use a stacking technique to measure the average HI content of a volume-limited sample of 1871 AGN host galaxies from a parent sample of galaxies selected from the SDSS and GALEX imaging surveys with stellar masses greater than 10^10 M_sun and redsh...
Potential signature of a quadrupolar Hubble expansion in Pantheon+ supernovae: The assumption of isotropy -- that the Universe looks the same in all directions on large scales -- is fundamental to the standard cosmological model. This model forms the building blocks of essentially all of our cosmological knowledge to...
The Evolution and Mass Dependence of Galaxy Cluster Pressure Profiles at 0.05 $\le z \le$ 0.60 and $4 \times 10^{14}$ M$_{\odot}$ $\le \textrm{M}_{500} \le 30 \times 10^{14}$ M$_{\odot}$: We have combined X-ray observations from Chandra with Sunyaev-Zel'dovich (SZ) effect data from Planck and Bolocam to measure int...
The LyA-LyC Connection: Evidence for an Enhanced Contribution of UV-faint Galaxies to Cosmic Reionization: The escape of ionizing Lyman Continuum (LyC) photons requires the existence of low-N_HI sightlines, which also promote escape of Lyman-Alpha (Lya). We use a suite of 2500 Lya Monte-Carlo radiative transfer simul...
Evidence for spin alignment of spiral and elliptical/S0 galaxies in filaments: Galaxies are not distributed randomly in the cosmic web but are instead arranged in filaments and sheets surrounding cosmic voids. Observationally there is still no convincing evidence of a link between the properties of galaxies and their...
Optical emission line properties of a sample of the broad-line AGNs: the Baldwin effect and eigenvector 1: We divide a sample of 302 type-1 AGNs into two subsamples based on the narrow line [OIII]/Hbeta_{NLR} ratio, since we expect that there will be a stronger starburst (HII region) contribution to the narrow line e...
3D-MHD simulations of the evolution of magnetic fields in FR II radio sources: 3D-MHD numerical simulations of bipolar, hypersonic, weakly magnetized jets and synthetic synchrotron observations are presented to study the structure and evolution of magnetic fields in FR II radio sources. The magnetic field setup in th...
CMB Angular Power Spectrum from Correlated Primordial Fluctuation: The usual inflationary scenario predicts a Gaussian random primordial density fluctuation, different Fourier modes of which do not correlate with each other. In this paper we propose a correlation between these different modes. A simple case is that the...
Polarizations of CMB and the Hubble tension: Future precision measurements of CMB polarizations can shed new light on the problem so called Hubble tension. The Hubble tension comes from the difference of the evolutions of the Hubble parameter which are determined with two different distance ladders. The standard distan...
What can the spatial distribution of galaxy clusters tell about their scaling relations?: We aim to quantify the capability of the inhomogeneous distribution of galaxy clusters, represented by the two-point statistics in Fourier space, to retrieve information on the underlying scaling relations. We make a case study ...
Three-Dimensional Simulations of Bi-Directed Magnetohydrodynamic Jets Interacting with Cluster Environments: We report on a series of three-dimensional magnetohydrodynamic simulations of active galactic nucleus (AGN) jet propagation in realistic models of magnetized galaxy clusters. We are primarily interested in the...
Intensity Mapping of the [CII] Fine Structure Line during the Epoch of Reionization: The atomic CII fine-structure line is one of the brightest lines in a typical star-forming galaxy spectrum with a luminosity ~ 0.1% to 1% of the bolometric luminosity. It is potentially a reliable tracer of the dense gas distribution...
NECOLA: Towards a Universal Field-level Cosmological Emulator: We train convolutional neural networks to correct the output of fast and approximate N-body simulations at the field level. Our model, Neural Enhanced COLA --NECOLA--, takes as input a snapshot generated by the computationally efficient COLA code and correc...
A common explanation of the Hubble tension and anomalous cold spots in the CMB: The standard cosmological paradigm narrates a reassuring story of a universe currently dominated by an enigmatic dark energy component. Disquietingly, its universal explaining power has recently been challenged by, above all, the $\sim4\s...
Solution for cosmological observables in the Starobinsky model of inflation: This paper focuses on the Starobinsky model of inflation. We derive solutions for various cosmological observables, such as the scalar spectral index $n_s$, the tensor-to-scalar ratio $r$ and their runnings, as well as the number of $e$-fold...
Photo-zSNthesis: Converting Type Ia Supernova Lightcurves to Redshift Estimates via Deep Learning: Upcoming photometric surveys will discover tens of thousands of Type Ia supernovae (SNe Ia), vastly outpacing the capacity of our spectroscopic resources. In order to maximize the science return of these observations in...
The Delay of Population III Star Formation by Supersonic Streaming Velocities: It has recently been demonstrated that coherent relative streaming velocities of order 30 km / s between dark matter and gas permeated the universe on scales below a few Mpc directly after recombination. We here use a series of high-resolu...
Diffuse Radio Emission in Abell 754: We present a low frequency study of the diffuse radio emission in the galaxy cluster A754. We present new 150 MHz image of the galaxy cluster A754 made with the Giant Metrewave Radio Telescope (GMRT) and discuss the detection of 4 diffuse features. We compare the 150 MHz image with ...
Opening the reheating box in multifield inflation: The robustness of multi-field inflation to the physics of reheating is investigated. In order to carry out this study, reheating is described in detail by means of a formalism which tracks the evolution of scalar fields and perfect fluids in interaction (the inflatons ...
Inferring the IGM thermal history during reionisation with the Lyman-$α$ forest power spectrum at redshift $z \simeq 5$: We use cosmological hydrodynamical simulations to assess the feasibility of constraining the thermal history of the intergalactic medium during reionisation with the Ly$\alpha$ forest at $z\simeq5$...
On the power spectrum generated during inflation: Recently there have been differing viewpoints on how to evaluate the curvature power spectrum generated during inflation. Since the primordial curvature power spectrum is the seed for structure formation and provides a link between observations and inflationary paramete...
Mid-IR Luminosities and UV/Optical Star Formation Rates at z<1.4: UV continuum and mid-IR emission constitute two widely used star formation indicators at intermediate and high redshifts. We study 2430 galaxies with z<1.4 in the Extended Groth Strip with MIPS 24 mic observations from FIDEL, spectroscopy from DEEP2, and...
Spectral Energy Distribution Models for Low-luminosity Active Galactic Nuclei in LINERs: Low-luminosity active galactic nuclei (LLAGNs) represent the bulk of the AGN population in the present-day universe and they trace the low-level accreting supermassive black holes. In order to probe the accretion and jet physical...
Toward A Consistent Picture For CRESST, CoGeNT and DAMA: Three dark matter direct detection experiments (DAMA/LIBRA, CoGeNT, and CRESST-II) have each reported signals which are not consistent with known backgrounds, but resemble that predicted for a dark matter particle with a mass of roughly $\sim$10 GeV and an elasti...
Spatial Distribution of Intracluster Light versus Dark Matter in Horizon Run 5: One intriguing approach for studying the dynamical evolution of galaxy clusters is to compare the spatial distributions among various components, such as dark matter, member galaxies, gas, and intracluster light (ICL). Utilizing the recen...
Cosmological test of local position invariance from the asymmetric galaxy clustering: The local position invariance (LPI) is one of the three major pillars of Einstein equivalence principle, ensuring the space-time independence on the outcomes of local experiments. The LPI has been tested by measuring the gravitation...
Testing the cosmic conservation of photon number with type Ia supernovae and ages of old objects: In this paper, we obtain luminosity distances by using ages of 32 old passive galaxies distributed over the redshift interval $0.11 < z < 1.84$ and test the cosmic conservation of photon number by comparing them with 580...
Understanding the nature of luminous red galaxies (LRGs): Connecting LRGs to central and satellite subhalos: We develop a novel abundance matching method to construct a mock catalog of luminous red galaxies (LRGs) in SDSS, using catalogs of halos and subhalos in N-body simulations for a LCDM model. Motivated by obser...
Constraining holographic inflation with WMAP: In a class of recently proposed models, the early universe is strongly coupled and described holographically by a three-dimensional, weakly coupled, super-renormalizable quantum field theory. This scenario leads to a power spectrum of scalar perturbations that differs from ...
Test of the Einstein equivalence principle with spectral distortions in the cosmic microwave background: The Einstein Equivalence Principle~(EEP) can be verified by the measurement of the spectral distortions of the Cosmic Microwave Background (CMB). The existence of energy-dependency in the cosmological redshift eff...
Type-Ia supernova rates and the progenitor problem, a review: The identity of the progenitor systems of type-Ia supernovae (SNe Ia) is a major unsolved problem in astrophysics. SN Ia rates are providing some striking clues. We review the basics of SN rate measurement, preach about some sins of SN rate measurement and a...
How the Dark Energy Can Reconcile \textit{Planck} with Local Determination of the Hubble Constant: We try to reconcile the tension between the local 2.4\% determination of Hubble constant and its global determination by $\textit{Planck}$ CMB data and BAO data through modeling the dark energy variously. We find that t...
PICS: Simulations of Strong Gravitational Lensing in Galaxy Clusters: Gravitational lensing has become one of the most powerful tools available for investigating the 'dark side' of the universe. Cosmological strong gravitational lensing, in particular, probes the properties of the dense cores of dark matter halos over ...
Modeling the reconstructed BAO in Fourier space: The density field reconstruction technique, which was developed to partially reverse the nonlinear degradation of the Baryon Acoustic Oscillation (BAO) feature in the galaxy redshift surveys, has been successful in substantially improving the cosmology constraints from r...
Effect of primordial non-Gaussianities on the far-UV luminosity function of high-redshift galaxies: implications for cosmic reionization: [Abridged] Understanding how the intergalactic medium (IGM) was reionized at z > 6 is one of the big challenges of current high redshift astronomy. It requires modelling the collap...
Noiseless Gravitational Lensing Simulations: The microphysical properties of the DM particle can, in principle, be constrained by the properties and abundance of substructures in DM halos, as measured through strong gravitational lensing. Unfortunately, there is a lack of accurate theoretical predictions for the lensin...
A 21-cm power spectrum at 48 MHz, using the Owens Valley Long Wavelength Array: The Large-aperture Experiment to detect the Dark Age (LEDA) was designed to measure the 21-cm signal from neutral hydrogen at Cosmic Dawn, $z \approx $15-30. Using observations made with the $\approx $ 200 m diameter core of the Owens Val...
The thermal history of the intergalactic medium at $3.9 \leq z \leq 4.3$: A new determination of the temperature of the intergalactic medium over $3.9 \leq z \leq 4.3$ is presented. We applied the curvature method on a sample of 10 high resolution quasar spectra from the Ultraviolet and Visual Echelle Spectrograph on t...
Probing ionizing radiation of L<~0.1L* star-forming galaxies at z>~3 with strong lensing: We show the effectiveness of strong lensing in the characterisation of Lyman continuum emission from faint L<~0.1L* star-forming galaxies at redshift >~ 3. Past observations of L>~L* galaxies at redshift >~3 have provided upper ...
Observed Scaling Relations for Strong Lensing Clusters: Consequences for Cosmology and Cluster Assembly: Scaling relations of observed galaxy cluster properties are useful tools for constraining cosmological parameters as well as cluster formation histories. One of the key cosmological parameters, sigma8, is constrai...
Interaction between collisionless galactic discs and nonaxissymmetric dark matter haloes: Using $N$-body simulations ($N\sim 10^6 - 10^7$), we examine how a non-axisymmetric dark halo affects the dynamical evolution of the structure in collisionless (stellar) discs. We demonstrate how the model parameters such as mas...
A numerical model of resistive generation of intergalactic magnetic field at cosmic dawn: Miniati and Bell (2011) proposed a mechanism for the generation of magnetic seeds that is based the finite resistivity of the low temperature IGM in the high redshift universe. In this model, cosmic-ray protons generated by the ...
Dark Energy Survey Year 1 Results: Methods for Cluster Cosmology and Application to the SDSS: We perform the first blind analysis of cluster abundance data. Specifically, we derive cosmological constraints from the abundance and weak-lensing signal of \redmapper\ clusters of richness $\lambda\geq 20$ in the redshift ...
Early-type galaxies at z~1.3. II. Masses and ages of early-type galaxies in different environments and their dependence on stellar population model assumptions: We have derived masses and ages for 79 early-type galaxies (ETGs) in different environments at z~1.3 in the Lynx supercluster and in the GOODS/CDF-S field ...
Formation rates of Dark Matter Haloes: We derive an estimate of the rate of formation of dark matter halos per unit volume as a function of the halo mass and redshift of formation. Analytical estimates of the number density of dark matter halos are useful in modeling several cosmological phenomena. We use the excursion...
Exact nonlinear inhomogeneities in $Λ$CDM cosmology: At a time when galaxy surveys and other observations are reaching unprecedented sky coverage and precision it seems timely to investigate the effects of general relativistic nonlinear dynamics on the growth of structures and on observations. Analytic inhomogeneous co...
The Kinematic Sunyaev-Zel'dovich Effect with Projected Fields: A Novel Probe of the Baryon Distribution with Planck, WMAP, and WISE Data: The kinematic Sunyaev-Zel'dovich (kSZ) effect --- the Doppler boosting of cosmic microwave background (CMB) photons due to Compton-scattering off free electrons with non-zero bulk ...
2MASS photometry and age estimate of globular clusters in the outer halo of M31: We present the first photometric results in J, H, and K_s from 2MASS imaging of 10 classical globular clusters in the far outer regions of M31. Combined with the V and I photometric data from previous literature, we constructed the color...
On the Spin Bias of Satellite Galaxies in the Local Group-like Environment: We utilize the Millennium-II simulation databases to study the spin bias of dark subhalos in the Local Group-like systems which have two prominent satellites with comparable masses. Selecting the group-size halos with total mass similar to th...
Fossil Groups Origins: I. RX J105453.3+552102 a very massive and relaxed system at z~0.5: The most accepted scenario for the origin of fossil groups (FGs) is that they are galaxy associations in which the merging rate was fast and efficient. These systems have assembled half of their mass at early epoch of the Univer...
Aspects of Dark Matter Annihilation in Cosmology: Cosmic microwave background (CMB) constraints on dark matter annihilation are a uniquely powerful tool in the quest to understand the nature of dark matter. Annihilation of dark matter to Standard Model particles between recombination and reionization heats baryons, ion...
The insignificance of major mergers in driving star formation at z~2: We study the significance of major-merger-driven star formation in the early Universe, by quantifying the contribution of this process to the total star formation budget in 80 massive (M* > 10^10 MSun) galaxies at z~2. Employing visually-classified m...
Star formation efficiency in the Barred Spiral Galaxy NGC 4303: We present new $^{12}$CO(J=1-0) observations of the barred galaxy NGC 4303 using the Nobeyama 45m telescope (NRO45) and the Combined Array for Research in Millimeter-wave Astronomy (CARMA). The H$\alpha$ images of barred spiral galaxies often show active s...
The Progenitor of Supernova 2011dh/PTF11eon in Messier 51: We have identified a luminous star at the position of supernova (SN) 2011dh/PTF11eon, in pre-SN archival, multi-band images of the nearby, nearly face-on galaxy Messier 51 (M51) obtained by the Hubble Space Telescope with the Advanced Camera for Surveys. This i...
Sensitivity of galaxy cluster dark energy constraints to halo modeling uncertainties: We perform a sensitivity study of dark energy constraints from galaxy cluster surveys to uncertainties in the halo mass function, bias and the mass-observable relation. For a set of idealized surveys, we evaluate cosmological constr...
Redshift Drift in LTB Void Universes: We study the redshift drift, i.e., the time derivative of the cosmological redshift in the Lema\^itre-Tolman-Bondi (LTB) solution in which the observer is assumed to be located at the symmetry center. This solution has often been studied as an anti-Copernican universe model to expl...
Toward a Measurement of the Transverse Peculiar Velocity of Galaxy Pairs: The transverse peculiar velocities caused by the mass distribution of large-scale structure provide a test of the theoretical matter power spectrum and the cosmological parameters that contribute to its shape. Typically, the matter density distri...
A Bayesian method for combining theoretical and simulated covariance matrices for large-scale structure surveys: Accurate and precise covariance matrices will be important in enabling planned cosmological surveys to detect new physics. Standard methods imply either the need for many N-body simulations in order to obt...
TDCOSMO IV: Hierarchical time-delay cosmography -- joint inference of the Hubble constant and galaxy density profiles: The H0LiCOW collaboration inferred via gravitational lensing time delays a Hubble constant $H_0=73.3^{+1.7}_{-1.8}$ km s$^{-1}{\rm Mpc}^{-1}$, describing deflector mass density profiles by either a p...
Astrophysical Distance Scale IV. Preliminary Zero-Point Calibration of the JAGB Method in the HST/WFC3-IR Broad J-Band (F110W) Filter: We present an absolute calibration of the J-region Asymptotic Giant Branch (JAGB) method using published photometry of resolved stars in 20 nearby galaxies observed with HST using the...
Resummed Perturbation Theory of Galaxy Clustering: The relationship between observed tracers such as galaxies and the underlying dark matter distribution is crucial in extracting cosmological information. As the linear bias model breaks down at quasi-linear scales, the standard perturbative approach of the nonlinear Eu...
CSST WL preparation I: forecast the impact from non-Gaussian covariances and requirements on systematics-control: The precise estimation of the statistical errors and accurate removal of the systematical errors are the two major challenges for the stage IV cosmic shear surveys. We explore their impact for the China S...
Phenomenology of dark energy: general features of large-scale perturbations: We present a systematic exploration of dark energy and modified gravity models containing a single scalar field non-minimally coupled to the metric. Even though the parameter space is large, by exploiting an effective field theory (EFT) form...
Stability of cosmological detonation fronts: The steady state propagation of a phase transition front is classified, according to hydrodynamics, as a deflagration or a detonation, depending on its velocity with respect to the fluid. These propagation modes are further divided into three types, namely, weak, Jouguet, an...
Mind the gap: the power of combining photometric surveys with intensity mapping: The long wavelength modes lost to bright foregrounds in the interferometric 21-cm surveys can partially be recovered using a forward modeling approach that exploits the non-linear coupling between small and large scales induced by gravit...
Combining galaxy and 21cm surveys: Acoustic waves traveling through the early Universe imprint a characteristic scale in the clustering of galaxies, QSOs and inter-galactic gas. This scale can be used as a standard ruler to map the expansion history of the Universe, a technique known as Baryon Acoustic Oscillations (BA...
Stochastic inflationary dynamics beyond slow-roll and consequences for primordial black hole formation: We consider the impact of quantum diffusion on inflationary dynamics during an ultra-slow-roll phase, which can be of particular significance for the formation of primordial black holes. We show, by means of a full...
Sunyaev-Zel'dovich anisotropy due to Primordial black holes: We investigate the Sunyaev-Zel'dovich (SZ) effect caused by primordial black holes (PBHs) on the cosmic microwave background (CMB) temperature fluctuations. The gas accreting on a PBH heats up by the release of the gravitational energy. As a result, the heate...
A Bayesian Approach to Locating the Red Giant Branch Tip Magnitude (Part I): We present a new approach for identifying the Tip of the Red Giant Branch (TRGB) which, as we show, works robustly even on sparsely populated targets. Moreover, the approach is highly adaptable to the available data for the stellar populatio...
Accounting for baryonic effects in cosmic shear tomography: Determining a minimal set of nuisance parameters using PCA: Systematic uncertainties that have been subdominant in past large-scale structure (LSS) surveys are likely to exceed statistical uncertainties of current and future LSS data sets, potentially limiti...
Constraints on the magnetic field in the inter-cluster bridge A399-A401: Galaxy cluster mergers are natural consequences of the structure formation in the Universe. Such events involve a large amount of energy ($\sim 10^{63}$ erg) dissipated during the process. Part of this energy can be channelled in particle accelera...
Cosmological dynamics and observational constraints on a viable $f(Q)$ non-metric gravity model: Inspired by an exponential $f(R)$ gravity model studied in the literature, in this work we introduce a new and viable $f(Q)$ gravity model, which can be represented as a perturbation of $\Lambda$CDM. Typically, within the...
The Central PNe Populations of External Galaxies with SAURON: Thanks to SAURON integral-field observations we uncovered the Planetary Nebulae (PNe) populations inhabiting the central and nuclear regions of our galactic neighbours M32 and M31, respectively, and discuss the significant differences between their correspon...
Coming of Age of the Standard Model: Cosmology now has a standard model - a remarkably simple description of the universe, its contents and its history. A symposium held last September in Cambridge, UK, gave this model a 'health check' and discussed fascinating questions that lie beyond it.
The spatial and velocity bias of linear density peaks and proto-haloes in the Lambda cold dark matter cosmology: We use high resolution N-body simulations to investigate the Lagrangian bias of cold dark matter haloes within the LCDM cosmology. Our analysis focuses on "proto-haloes", which we identify in the simulatio...
Simulating Calibration and Beam Systematics for a Future CMB Space Mission with the TOAST Package: We address in this work the instrumental systematic errors that can potentially affect the forthcoming and future Cosmic Microwave Background experiments aimed at observing its polarized emission. In particular, we focu...
Slow-roll Inflation with the Gauss-Bonnet and Chern-Simons Corrections: We study slow-roll inflation with the Gauss-Bonnet and Chern-Simons corrections. We obtain general formulas for the observables: spectral indices, tensor-to-scalar ratio and circular polarization of gravitational waves. The Gauss-Bonnet term violat...
On Model Selection in Cosmology: We review some of the common methods for model selection: the goodness of fit, the likelihood ratio test, Bayesian model selection using Bayes factors, and the classical as well as the Bayesian information theoretic approaches. We illustrate these different approaches by comparing model...
Further understanding the interaction between dark energy and dark matter: current status and future directions: The interaction between dark matter and dark energy can be incorporated into field theory models of dark energy that have proved successful in alleviating the coincidence problem. We review recent advances...
New Constraints On Cosmic Polarization Rotation Including SPTpol B-mode Polarization Observations: We present an update of the cosmic polarization rotation (CPR) constraint from the recent SPTpol measurements of sub-degree B-mode polarization in the cosmic microwave background (CMB) of 100 square degrees of sky. Our ...
Pahs, Ionized Gas, and Molecular Hydrogen in Brightest Cluster Galaxies of Cool Core Clusters of Galaxies: We present measurements of 5-25 {\mu}m emission features of brightest cluster galaxies (BCGs) with strong optical emission lines in a sample of 9 cool-core clusters of galaxies observed with the Infrared Spectro...
A New Equation of State for Dark Energy Model: A new parameterization for the dark energy equation of state(EoS) is proposed and some of its cosmological consequences are also investigated. This new parameterization is the modification of Efstathiou' dark energy EoS parameterization. $w (z)$ is a well behaved function ...
Canonical single field slow-roll inflation with a non-monotonic tensor-to-scalar ratio: We take a pragmatic, model independent approach to single field slow-roll canonical inflation by imposing conditions, not on the potential, but on the slow-roll parameter $\epsilon(\phi)$ and its derivatives $\epsilon^{\prime }(\p...
Hill-climbing dark inflation: Within the framework of the scalar-tensor theory we consider a hill-climbing inflation, in which the effective Planck mass increases in time. We obtain the Einstein frame potential with infinitely long and flat plateau as we approach towards the strong coupling regime, together with a run-...