anchor
stringlengths
50
3.92k
positive
stringlengths
55
6.16k
Comparing the scalar-field dark energy models with recent observations: We investigate the general properties of a class of scalar-field dark energy models (i.e., $\phi$CDM models) which behave like cosmological trackers at early times. Particularly, we choose three $\phi$CDM models with typical potentials, i.e., $V(\p...
Possible discrimination of black hole origins from the lensing rate of DECIGO and B-DECIGO sources: In this paper, we forecast the expected detection rates and redshift distributions of gravitationally lensed gravitational waves (GWs) from three different mass distributions of primordial black holes (PBHs) and two st...
Dark Matter as a Possible New Energy Source for Future Rocket Technology: Current rocket technology can not send the spaceship very far, because the amount of the chemical fuel it can take is limited. We try to use dark matter (DM) as fuel to solve this problem. In this work, we give an example of DM engine using dark ...
SPHS: Smoothed Particle Hydrodynamics with a higher order dissipation switch: We present a novel implementation of Smoothed Particle Hydrodynamics (SPHS) that uses the spatial derivative of the velocity divergence as a higher order dissipation switch. Our switch -- which is second order accurate -- detects flow conve...
A New Probe of Gaussianity and Isotropy applied to the CMB Maps: We introduce a new mathematical tool (a direction-dependent probe) to analyse the randomness of purported isotropic Gaussian random fields on the sphere. We apply the probe to assess the full-sky cosmic microwave background (CMB) temperature maps produced...
Optimizing spectral stacking for 21-cm observations of galaxies: accuracy assessment and symmetrized stacking: We present an assessment of the accuracy of common operations performed in $21$-cm spectral line stacking experiments. To this end, we generate mock interferometric data surveying the 21-cm emission at frequ...
Do cosmological observations allow a negative $Λ$?: In view of the recent measurement of $H_{0}$ from HST and SH0ES team, we explore the possibility of existence of a negative cosmological constant (AdS vacua in the dark energy sector) in the Universe. In this regard, we consider quintessence fields on top of a negativ...
Running Vacuum Cosmological Models: Linear Scalar Perturbations: In cosmology, phenomenologically motivated expressions for running vacuum are commonly parametrized as linear functions $\Lambda(H^2)$ or $\Lambda(R)$. Such kind of models assume an equation of state for vacuum given by $\,\overline P_\Lambda=-\,\overline...
Direct Dark Matter Search with the CRESST-II Experiment: The quest for the particle nature of dark matter is one of the big open questions of modern physics. The CRESST-II experiment, located at the Gran Sasso laboratory in Italy, is optimised for the detection of the elastic scattering of dark matter particles with or...
Faraday scaling and the Bicep2 observations: As repeatedly speculated in the past, the linear polarization of the Cosmic Microwave Background can be rotated via the Faraday effect. An economic explanation of the recent Bicep2 observations, not relying on long-wavelength tensor modes of the geometry, would stipulate tha...
An analytic implementation of the IR-resummation for the BAO peak: We develop an analytic method for implementing the IR-resummation of arXiv:1404.5954, which allows one to correctly and consistently describe the imprint of baryon acoustic oscillations (BAO) on statistical observables in large-scale structure. We show ...
Cosmological constraints from line intensity mapping with interlopers: Understanding the formation and evolution of the Universe is crucial for cosmological studies, and the line intensity mapping provides a powerful tool for this kind of study. We propose to make use of multipole moments of redshift-space line intensi...
Inner cusps of the first dark matter haloes: Formation and survival in a cosmological context: We use very high resolution cosmological zoom simulations to follow the early evolution of twelve first-generation haloes formed from gaussian initial conditions with scale-free power spectra truncated on small scales by a ...
The Atacama Cosmology Telescope: Delensed Power Spectra and Parameters: We present LCDM cosmological parameter constraints obtained from delensed microwave background power spectra. Lensing maps from a subset of DR4 data from the Atacama Cosmology Telescope (ACT) are used to undo the lensing effect in ACT spectra obser...
Tachyonic fields in cosmology: The possibility of explanation of accelerated expansion of the Universe by tachyonic scalar fields which homogeneously fill the world is discussed. The dependences of potential and kinetic term on scale factor are deduced for the case of quintessential and phantom dark energy with general...
Halo mass distribution reconstruction across the cosmic web: We study the relation between halo mass and its environment from a probabilistic perspective. We find that halo mass depends not only on local dark matter density, but also on non-local quantities such as the cosmic web environment and the halo-exclusion effe...
Resolving the timing problem of the globular clusters orbiting the Fornax dwarf galaxy: We re-investigate the old problem of the survival of the five globular clusters orbiting the Fornax dwarf galaxy in both standard and modified Newtonian dynamics. For the first time in the history of the topic, we use accurate mas...
X-ray and Sunyaev-Zeldovich properties of the WHIM: We use numerical simulations to predict the soft X-ray ([0.4-0.6] keV) and Sunyaev-Zeldovich signal (at 150 GHz) from the large scale structure in the Universe and then compute 2-point statistics to study the spatial distribution and time evolution of the signals. The...
Effects of superstructure environment on galaxy groups: We analyse properties of galaxy groups and their dependence on the large scale environment as defined by superstructures. We find that group galaxy cross correlations depend only on group properties regardless the groups reside in superstructures. This indicates t...
Importance of high-frequency bands for thermal dust removal in ECHO: The Indian Consortium of Cosmologists has proposed a cosmic microwave background (CMB) space mission, Exploring Cosmic History and Origin (ECHO). A major scientific goal of the mission is to detect the primordial B-mode signal of CMB polarization. The...
The Linear Point: A cleaner cosmological standard ruler: We show how a characteristic length scale imprinted in the galaxy two-point correlation function, dubbed the "linear point", can serve as a comoving cosmological standard ruler. In contrast to the Baryon Acoustic Oscillation peak location, this scale is constant ...
Dynamical cluster masses from photometric surveys: The masses of galaxy clusters can be measured using data obtained exclusively from wide photometric surveys in one of two ways: directly from the amplitude of the weak lensing signal or, indirectly, through the use of scaling relations calibrated using binned lensing m...
Dark Radiation in extended cosmological scenarios: Recent cosmological data have provided evidence for a "dark" relativistic background at high statistical significance. Parameterized in terms of the number of relativistic degrees of freedom Neff, however, the current data seems to indicate a higher value than the one ...
Testing one-loop galaxy bias: Power spectrum: We test the regime of validity of one-loop galaxy bias for a wide variety of biased tracers. Our most stringent test asks the bias model to simultaneously match the galaxy-galaxy and galaxy-mass spectrum, using the measured nonlinear matter spectrum from the simulations to ...
Extremely rapid star cluster disruption in high-shear circumnuclear starburst rings: the unusual case of NGC 7742: All known mass distributions of recently formed star cluster populations resemble a "universal" power-law function. Here we assess the impact of the extremely disruptive environment in NGC 7742's circumn...
X-ray Properties of SPT Selected Galaxy Clusters at 0.2<z<1.5 Observed with XMM-Newton: We present measurements of the X-ray observables of the intra-cluster medium (ICM), including luminosity $L_X$, ICM mass $M_{ICM}$, emission-weighted mean temperature $T_X$, and integrated pressure $Y_X$, that are derived from XMM...
The nature of non-Gaussianity and statistical isotropy of the 408 MHz Haslam synchrotron map: Accurate component separation of full-sky maps in the radio and microwave frequencies, such as the cosmic microwave background (CMB), relies on a thorough understanding of the statistical properties of the Galactic foregroun...
Escape from the swamp with spectator: In the context of string theory, several conjectural conditions have been proposed for low energy effective field theories not to be in swampland, the UV-incomplete class. The recent ones represented by the de Sitter and trans-Planckian censorship conjectures in particular seem to ...
The mass of first stars: We perform a three dimensional radiation hydrodynamics simulation to investigate the formation of first stars from initial collapse of a primordial gas cloud to formation and growth of protostars. The simulation is integrated until 0.1 Myrs after the formation of the primary protostar by which ...
Faraday Rotation Measure due to the Intergalactic Magnetic Field: Studying the nature and origin of the intergalactic magnetic field (IGMF) is an outstanding problem of cosmology. Measuring Faraday rotation would be a promising method to explore the IGMF in the large-scale structure (LSS) of the universe. We investigat...
The Snapshot Hubble U-Band Cluster Survey (SHUCS). I. Survey Description and First Application to the Mixed Star Cluster Population of NGC 4041: We present the Snapshot Hubble U-band Cluster Survey (SHUCS), a project aimed at characterizing the star cluster populations of ten nearby galaxies (d<23 Mpc, half within 12...
Post-$Planck$ constraints on interacting vacuum energy: We present improved constraints on an interacting vacuum model using updated astronomical observations including the first data release from Planck. We consider a model with one dimensionless parameter, $\alpha$, describing the interaction between dark matter and ...
Resolving primordial physics through correlated signatures: We discuss correlations among spectral observables as a new tool for differentiating between models for the primordial perturbation. We show that if generated in the isocurvature sector, a running of the scalar spectral index is correlated with the statistical...
Tomographic analyses of the CMB lensing and galaxy clustering to probe the linear structure growth: In a tomographic approach, we measure the cross-correlation between the CMB lensing reconstructed from the Planck satellite and the galaxies of the photometric redshift catalogue based on the combination of the South G...
On the absence of radio halos in clusters with double relics: Pairs of radio relics are believed to form during cluster mergers, and are best observed when the merger occurs in the plane of the sky. Mergers can also produce radio halos, through complex processes likely linked to turbulent re-acceleration of cosmic-ray ...
Lenticular galaxy IC 719: current building of the counterrotating large-scale stellar disk: We have obtained and analyzed long-slit spectral data for the lenticular galaxy IC 719. In this gas-rich S0 galaxy, its large-scale gaseous disk counterrotates the global stellar disk. Moreover in the IC 719 disk we have detec...
Linear cosmological constraints on 2-body decaying dark matter scenarios and the $S_8$ tension: The '$S_8$ tension' is a longstanding discrepancy between the cosmic microwave background (CMB) and weak gravitational lensing determination of the amplitude of matter fluctuations, parametrized as $S_8\equiv\sigma_8(\Omeg...
The Cosmic Linear Anisotropy Solving System (CLASS) II: Approximation schemes: Boltzmann codes are used extensively by several groups for constraining cosmological parameters with Cosmic Microwave Background and Large Scale Structure data. This activity is computationally expensive, since a typical project requires f...
First direct metallicity measurement of a lensed star-forming galaxy at z=1.7: We present the rest-frame optical spectrum of a strongly lensed galaxy at redshift z =1.7 behind the cluster Abell 1689. We detect the temperature sensitive auroral line [O III] 4363, which allows the first direct metallicity measurement f...
KiDS-1000 Methodology: Modelling and inference for joint weak gravitational lensing and spectroscopic galaxy clustering analysis: We present the methodology for a joint cosmological analysis of weak gravitational lensing from the fourth data release of the ESO Kilo-Degree Survey (KiDS-1000) and galaxy clustering from...
Cosmic evolution of radio selected active galactic nuclei in the COSMOS field: We explore the cosmic evolution of radio AGN with low radio powers (L_1.4GHz < 5\times10^25 W/Hz) out to z=1.3 using to-date the largest sample of ~600 low luminosity radio AGN at intermediate redshift drawn from the VLA-COSMOS survey. We ...
The Araucaria Project. The Distance to the Small Magellanic Cloud from Near-Infrared Photometry of RR Lyrae Variables: We have obtained deep infrared J and K band observations of nine 4.9x4.9 arcmin fields in the Small Magellanic Cloud (SMC) with the ESO New Technology Telescope equipped with the SOFI infrared camera...
Quasar Ionization Front Lyα Emission in an Inhomogeneous Intergalactic Medium: The conditions within the ionization front of a quasar during reionization (T ~ 30,000 K, neutral hydrogen fraction ~ 0.5) are ideal for producing Lyman-alpha emission via collisional excitation of hydrogen atoms. Observations of this emis...
The Integrated Sachs-Wolfe Effect in Time Varying Vacuum Model: The integrated Sachs-Wolfe (ISW) effect is an important implication for dark energy. In this paper, we have calculated the power spectrum of the ISW effect in the time varying vacuum cosmological model, where the model parameter $\beta=4.407$ is obtained b...
Global e-VLBI observations of the gamma-ray narrow line Seyfert 1 PMN J0948+0022: There is growing evidence of relativistic jets in radio-loud narrow-line Seyfert 1 (RL-NLS1) galaxies. We constrain the observational properties of the radio emission in the first RL-NLS1 galaxy ever detected in gamma-rays, PMN J0948+00...
Observations of a nearby filament of galaxy clusters with the Sardinia Radio Telescope: We report the detection of diffuse radio emission which might be connected to a large-scale filament of the cosmic web covering a 8deg x 8deg area in the sky, likely associated with a z~0.1 over-density traced by nine massive gala...
Baryon number transfer could delay Quark-Hadron transition in cosmology: In the early Universe, strongly interacting matter was a quark-gluon plasma. Both lattice computations and heavy ion collision experiments however tell us that, in the absence of chemical potentials, no plasma survives at $T <\sim 150$ MeV. The co...
Inflation Wars: A New Hope: We explore a class of primordial power spectra that can fit the observed anisotropies in the cosmic microwave background well and that predicts a value for the Hubble parameter consistent with the local measurement of $H_0 = 74$ km/s/Mpc. This class of primordial power spectrum consists of a...
Fine structure constant measurements in quasar absorption systems: Detecting any evolution of dimensionless in the ratios of physical quantities, such as the fine structure constant, would prove that the Weak Equivalence Principle is violated and lead to a paradigm shift in physics. High resolution spectroscopy of quas...
A Strange Mènage Á Trois: The Magellanic Clouds may have joined our Milky Way system quite recently. The Large Magellanic Cloud turns out to be a remarkably luminous object that is close to the upper luminosity limit of the class of magellanic irregular galaxies.
Short Review of the main achievements of the Scalar Field, Fuzzy, Ultralight, Wave, BEC Dark Matter model: The Scalar Field Dark Matter model has been known in various ways throughout its history; Fuzzy, BEC, Wave, Ultralight, Axion-like Dark Matter, etc. All of them consist in proposing that the dark matter of the u...
The impact of extragalactic foregrounds on internal delensing of CMB B-mode polarization: The search for primordial $B$-mode polarization of the CMB is limited by the sample variance of $B$-modes produced at later times by gravitational lensing. Constraints can be improved by `delensing': using some proxy of the matt...
Evolution of the Red Sequence Giant to Dwarf Ratio in Galaxy Clusters out to z ~ 0.5: We analyze deep g' and r' band data of 97 galaxy clusters imaged with MegaCam on the Canada-France-Hawaii telescope. We compute the number of luminous (giant) and faint (dwarf) galaxies using criteria based on the definitions of de ...
The R_h = ct Universe: The backbone of standard cosmology is the Friedmann-Robertson-Walker solution to Einstein's equations of general relativity (GR). In recent years, observations have largely confirmed many of the properties of this model, which is based on a partitioning of the universe's energy density into three...
Novel null tests for the spatial curvature and homogeneity of the Universe and their machine learning reconstructions: A plethora of observational data obtained over the last couple of decades has allowed cosmology to enter into a precision era and has led to the foundation of the standard cosmological constant and c...
Efficiently evaluating loop integrals in the EFTofLSS using QFT integrals with massive propagators: We develop a new way to analytically calculate loop integrals in the Effective Field Theory of Large Scale-Structure. Previous available methods show severe limitations beyond the one-loop power spectrum due to analyti...
NH and Mg Index Trends in Elliptical Galaxies: We examine the spectrum in the vicinity of the NH3360 index of Davidge & Clark (1994), which was defined to measure the NH absorption around 3360 \AA and which shows almost no trend with velocity dispersion (Toloba et al. 2009), unlike other N- sensitive indices, which sho...
Gravitational waves at interferometer scales and primordial black holes in axion inflation: We study the prospects of detection at terrestrial and space interferometers, as well as at pulsar timing array experiments, of a stochastic gravitational wave background which can be produced in models of axion inflation. Thi...
Halo abundances within the cosmic web: We investigate the dependence of the mass function of dark-matter haloes on their environment within the cosmic web of large-scale structure. A dependence of the halo mass function on large-scale mean density is a standard element of cosmological theory, allowing mass-dependent bi...
The evolution of the star formation activity per halo mass up to redshift ~ 1.6 as seen by Herschel: Star formation in massive galaxies is quenched at some point during hierarchical mass assembly. To understand where and when the quenching processes takes place, we study the evolution of the total star formation rate...
Averaging the AGN X-ray spectra from deep Chandra fields: The X-ray spectra of Active Galactic Nuclei (AGN) carry the signatures of the emission from the central region, close to the Super Massive Black Hole (SMBH). For this reason, the study of deep X-ray spectra is a powerful instrument to investigate the origin of t...
SPT 0538-50: Physical conditions in the ISM of a strongly lensed dusty star-forming galaxy at z=2.8: We present observations of SPT-S J053816-5030.8, a gravitationally-lensed dusty star forming galaxy (DSFG) at z = 2.7817, first discovered at millimeter wavelengths by the South Pole Telescope. SPT 0538-50 is typical ...
Growth rate of cosmological perturbations at z ~ 0.1 from a new observational test: Spatial variations in the distribution of galaxy luminosities, estimated from redshifts as distance proxies, are correlated with the peculiar velocity field. Comparing these variations with the peculiar velocities inferred from galaxy...
Magnified or multiply imaged? - Search strategies for gravitationally lensed supernovae in wide-field surveys: Strongly lensed supernovae can be detected as multiply imaged or highly magnified transients. In order to compare the performances of these two observational strategies, we calculate expected discovery rates...
Extending and Calibrating the Velocity dependent One-Scale model for Cosmic Strings with One Thousand Field Theory Simulations: Understanding the evolution and cosmological consequences of topological defect networks requires a combination of analytic modeling and numerical simulations. The canonical analytic model f...
Black Holes in our Galactic Halo: Compatibility with FGST and PAMELA Data and Constraints on the First Stars: 10 to 10^5 solar mass black holes with dark matter spikes that formed in early minihalos and still exist in our Milky Way Galaxy today are examined in light of recent data from the Fermi Gamma-Ray Space Teles...
A Revised Broad-Line Region Radius and Black Hole Mass for the Narrow-Line Seyfert 1 NGC 4051: We present the first results from a high sampling rate, multi-month reverberation mapping campaign undertaken primarily at MDM Observatory with supporting observations from telescopes around the world. The primary goal of t...
Pioneer Anomaly in Perturbed FRW Metric: In this manuscript, it is shown that the Pioneer anomaly is the local evidence for an expanding universe. In other words, its value is a direct measure of the Hubble constant while its sign shows the expanding behavior of the dynamics of the universe. This analysis is obtained b...
HI Lyman-alpha equivalent widths of stellar populations: We have compiled a library of stellar Lyman-alpha equivalent widths in O and B stars using the model atmosphere codes CMFGEN and TLUSTY, respectively. The equivalent widths range from about 0 to 30 \AA in absorption for early-O to mid-B stars. The purpose of this...
Enhanced Nitrogen in Morphologically Disturbed Blue Compact Galaxies at 0.20 < z < 0.35: Probing Galaxy Merging Features: We present a study of correlations between the elemental abundances and galaxy morphologies of 91 blue compact galaxies (BCGs) at z=0.20-0.35 with Sloan Digital Sky Survey (SDSS) DR7 data. We clas...
Two-Field quintessential Higgs Inflation: We study a two-field quintessential Higgs inflation model in which a quintessence field with an exponential potential $e^{-\beta\phi/M_P}$ is coupled to the Higgs field from the beginning of inflation. The Higgs field itself is also non-minimally coupled to gravity. The inflati...
Flux and Photon Spectral Index Distributions of Fermi-LAT Blazars And Contribution To The Extragalactic Gamma-ray Background: We present a determination of the distributions of photon spectral index and gamma-ray flux - the so called LogN-LogS relation - for the 352 blazars detected with a greater than approximately ...
Multiwavelength investigations of co-evolution of bright custer galaxies: We report a systematic multi-wavelength investigation of environments of the brightest cluster galaxies (BCGs), using the X-ray data from the Chandra archive, and optical images taken with 34'x 27' field-of-view Subaru Suprime-Cam. Our goal is to...
A mid-IR study of Hickson Compact Groups II. Multi-wavelength analysis of the complete GALEX-Spitzer Sample: We present a comprehensive study on the impact of the environment of compact galaxy groups on the evolution of their members using a multi-wavelength analysis, from the UV to the infrared, for a sample of 32 H...
Constraining the Variation of the Fine Structure Constant with Observations of Narrow Quasar Absorption Lines: Attempts to measure the variability of the fine structure constant alpha over cosmological time, using spectra of high redshift quasars have produced conflicting results. We use the Many Multiplet (MM) metho...
Unknowns and unknown unknowns: from dark sky to dark matter and dark energy: Answering well-known fundamental questions is usually regarded as the major goal of science. Discovery of other unknown and fundamental questions is, however, even more important. Recognition that "we didn't know anything" is the basic scien...
The core fundamental plane of B2 radio galaxies: The photometric, structural and kinematical properties of the centers of elliptical galaxies, harbor important information of the formation history of the galaxies. In the case of non active elliptical galaxies these properties are linked in a way that surface brightness...
Nonlinear Structure Formation with the Environmentally Dependent Dilaton: We have studied the nonlinear structure formation of the environmentally dependent dilaton model using $N$-body simulations. We find that the mechanism of suppressing the scalar fifth force in high-density regions works very well. Within the para...
Infrared 3-4 Micron Spectroscopy of Nearby PG QSOs and AGN-Nuclear Starburst Connections in High-luminosity AGN Populations: We present the results of infrared L-band (3-4 micron) slit spectroscopy of 30 PG QSOs at z < 0.17, the representative sample of local high-luminosity, optically selected AGNs. The 3.3 micron p...
The influence of galaxy mergers on the mass dispersion of brightest cluster galaxies: The absolute magnitude of the brightest galaxy of clusters varies remarkably little and is nearly independent of all other physical properties of the cluster as, e.g., its spatial extension or its richness. The question arises wheth...
Flows For The Masses: A multi-fluid non-linear perturbation theory for massive neutrinos: Velocity dispersion of the massive neutrinos presents a daunting challenge for non-linear cosmological perturbation theory. We consider the neutrino population as a collection of non-linear fluids, each with uniform initial mome...
Probing cosmic acceleration by strong gravitational lensing systems: Recently, some divergent conclusions about cosmic acceleration were obtained using type Ia supernovae (SNe Ia), with opposite assumptions on the intrinsic luminosity evolution. In this paper, we use strong gravitational lensing systems to probe the co...
Absolute calibration of the polarisation angle for future CMB B-mode experiments from current and future measurements of the Crab nebula: A tremendous international effort is currently dedicated to observing the so-called primordial B modes of the Cosmic Microwave Background (CMB) polarisation. If measured, this fain...
Emulation of the Cosmic Dawn 21-cm Power Spectrum and Classification of Excess Radio Models Using an Artificial Neural Network: The cosmic 21-cm line of hydrogen is expected to be measured in detail by the next generation of radio telescopes. The enormous dataset from future 21-cm surveys will revolutionize our under...
Spectral distortions from the dissipation of tensor perturbations: Spectral distortions of the cosmic microwave background (CMB) may become a powerful probe of primordial perturbations at small scales. Existing studies of spectral distortions focus almost exclusively on primordial scalar metric perturbations. Similarly...
Cosmic microwave background limits on accreting primordial black holes: Interest in the idea that primordial black holes (PBHs) might comprise some or all of the dark matter has recently been rekindled following LIGO's first direct detection of a binary-black-hole merger. Here we revisit the effect of accreting PBHs on...
Anisotropies in the stochastic gravitational-wave background: Formalism and the cosmic string case: We develop a powerful analytical formalism for calculating the energy density of the stochastic gravitational wave background, including a full description of its anisotropies. This is completely general, and can be ap...
Quantifying cosmic variance: We determine an expression for the cosmic variance of any "normal" galaxy survey based on examination of M* +/- 1 mag galaxies in the SDSS DR7 data cube. We find that cosmic variance will depend on a number of factors principally: total survey volume, survey aspect ratio, and whether the ar...
Partially Cooled Shocks: Detectable Precursors in the Warm/Hot Intergalactic Medium: I present computations of the integrated column densities produced in the post-shock cooling layers and in the radiative precursors of partially-cooled fast shocks as a function of the shock age. The results are applicable to the sho...
Testing and selecting cosmological models with ultra-compact radio quasars: In this paper, we place constraints on four alternative cosmological models under the assumption of the spatial flatness of the Universe: CPL, EDE, GCG and MPC. A new compilation of 120 compact radio quasars observed by very-long-baseline int...
IGM Constraints from the SDSS-III/BOSS DR9 Ly-alpha Forest Flux Probability Distribution Function: The Ly$\alpha$ forest transmission probability distribution function (PDF) is an established probe of the intergalactic medium (IGM) astrophysics, especially the temperature-density relationship of the IGM. We measure t...
Shaken, Not Stirred: The Disrupted Disk of the Starburst Galaxy NGC 253: Near-infrared images obtained with the CFHT WIRCam are used to investigate the recent history of the nearby Sculptor Group spiral NGC 253. The distribution of stars in the disk is lop-sided, in the sense that the projected density of AGB stars in ...
Multiple Dark Matter as a self-regulating mechanism for dark sector interactions: (Abridged) Present cosmological constraints and the absence of a direct detection and identification of any dark matter particle candidate leave room to the possibility that the dark sector of the Universe be actually more complex than ...
The effect of pressure-anisotropy-driven kinetic instabilities on magnetic field amplification in galaxy clusters: The intracluster medium (ICM) is the low-density diffuse magnetized plasma in galaxy clusters, which reaches virial temperatures of up to 10^8 K. Under these conditions, the plasma is weakly collisional ...
The transition from population III to population II-I star formation: We present results from the first cosmological simulations which study the onset of primordial, metal-free (population III), cosmic star formation and the transition to the present-day, metal-rich star formation (population II-I), including molecular...
Building models of the Universe with hydrodynamic simulations: Hydrodynamic simulations have become irreplaceable in modern cosmology for exploring complex systems and making predictions to steer future observations. In Chapter 1, we begin with a philosophical discussion on the role of simulations in science. We argue ...
Euclid preparation. TBD. The effect of linear redshift-space distortions in photometric galaxy clustering and its cross-correlation with cosmic shear: Cosmological surveys planned for the current decade will provide us with unparalleled observations of the distribution of galaxies on cosmic scales, by means of which ...
Radio and Mid-Infrared Properties of Compact Starbursts: Distancing Themselves from the Main Sequence: We investigate the relationship between 8.44\,GHz brightness temperatures and 1.4 to 8.44\,GHz radio spectral indices with 6.2\,$\mu$m polycyclic aromatic hydrocarbon (PAH) emission and 9.7\,$\mu$m silicate absorpti...
Evolution of the equation of state parameters of cosmological tachyonic field components through mutual interaction: We study the perturbed equation of state (EOS) parameters of the cosmological tachyonic scalar field components and their mutual time-dependent interaction. It is shown that the discrete temperature-...
Constraining cosmic reionization with quasar, gamma ray burst, and Lya emitter observations: We investigate the cosmic reionization history by comparing semi-analytical models of the Lya forest with observations of high-z quasars and gamma ray bursts absorption spectra. In order to constrain the reionization epoch z_...
Early star-forming galaxies and the reionization of the Universe: Star forming galaxies represent a valuable tracer of cosmic history. Recent observational progress with Hubble Space Telescope has led to the discovery and study of the earliest-known galaxies corresponding to a period when the Universe was only ~800 mil...
Reconstruction of inflationary scenarios in non-conservative unimodular gravity: Unimodular gravity is an alternative theory of gravity to general relativity. The gravitational field equations are given by the trace-free version of Einstein's field equations. Due to the structure of the theory, unimodular gravity adm...
The KBC Void: Consistency with Supernovae Type Ia and the Kinematic SZ Effect in a $Λ$LTB Model: There is substantial and growing observational evidence from the normalized luminosity density in the near-infrared that the local universe is under-dense on scales of several hundred Megaparsecs. We test whether our para...
Probing cosmic homogeneity in the Local Universe: We investigate the transition scale to homogeneity, $R_H$, using as cosmic tracer the spectroscopic sample of blue galaxies from the Sloan Digital Sky Survey (SDSS). Considering the spatial distribution of the galaxy sample we compute the two point correlation function ...
Precious Metals in SDSS Quasar Spectra II: Tracking the Evolution of Strong, 0.4 < z < 2.3 MgII Absorbers with Thousands of Systems: We have performed an analysis of over 34,000 MgII doublets at 0.36 < z < 2.29 in Sloan Digital Sky Survey (SDSS) Data-Release 7 quasar spectra; the catalog, advanced data products, and ...
Cosmology with Planck T-E correlation coefficient: Tensions in cosmological parameters measurement motivate a revisit of the effects of instrumental systematics. In this article, we focus on the Pearson's correlation coefficient of the cosmic microwave background temperature and polarization E modes $\mathcal{R}_\ell^{...
A novel approach to quantifying the sensitivity of current and future cosmological datasets to the neutrino mass ordering through Bayesian hierarchical modeling: We present a novel approach to derive constraints on neutrino masses from cosmological data, while taking into account our ignorance of the neutrino mass ...
The SDSS Coadd: 275 deg^2 of Deep SDSS Imaging on Stripe 82: We present details of the construction and characterization of the coaddition of the Sloan Digital Sky Survey Stripe 82 \ugriz\ imaging data. This survey consists of 275 deg$^2$ of repeated scanning by the SDSS camera of $2.5\arcdeg$ of $\delta$ over $-50\arc...
Towards Cosmography of the Local Universe: Anisotropies in the distance-redshift relation of cosmological sources are expected due to large-scale inhomogeneities in the local Universe. When the observed sources are tracing a large-scale matter flow in a general spacetime geometry, the distance-redshift relation with it...
Probing Dark Matter Clumps, Strings and Domain Walls with Gravitational Wave Detectors: Gravitational wave astronomy has recently emerged as a new way to study our Universe. In this work, we survey the potential of gravitational wave interferometers to detect macroscopic astrophysical objects comprising the dark matt...
Bayes-X: a Bayesian inference tool for the analysis of X-ray observations of galaxy clusters: We present the first public release of our Bayesian inference tool, Bayes-X, for the analysis of X-ray observations of galaxy clusters. We illustrate the use of Bayes-X by analysing a set of four simulated clusters at z=0.2-...
On the filamentary environment of galaxies: The correlation between the large-scale distribution of galaxies and their spectroscopic properties at z=1.5 is investigated using the Horizon MareNostrum cosmological run. We have extracted a large sample of 10^5 galaxies from this large hydrodynamical simulation featuring...
Revisiting progenitor-age dependence of type Ia supernova luminosity standardization process: Much of the research in supernova cosmology is based on an assumption that the peak luminosity of type Ia supernovae (SNe Ia), after a standardization process, is independent of the galactic environment. A series of recent s...
Optimal Weighting in Galaxy Surveys: Application to Redshift-Space Distortions: Using multiple tracers of large-scale structure allows to evade the limitations imposed by sampling variance for some parameters of interest in cosmology. We demonstrate the optimal way of carrying out a multitracer analysis in a galaxy r...
Cosmography of the Local Universe by Multipole Analysis of the Expansion Rate Fluctuation Field: We explore the possibility of characterizing the expansion rate on local cosmic scales $(z \lesssim 0.1)$, where the cosmological principle is violated, in a model-independent manner, i.e. in a more meaningful and compreh...
Annihilation Signatures of Hidden Sector Dark Matter Within Early-Forming Microhalos: If the dark matter is part of a hidden sector with only very feeble couplings to the Standard Model, the lightest particle in the hidden sector will generically be long-lived and could come to dominate the energy density of the univ...
A new probe of the small-scale primordial power spectrum: astrometric microlensing by ultracompact minihalos: The dark matter enclosed in a density perturbation with a large initial amplitude (delta-rho/rho > 1e-3) collapses shortly after recombination and forms an ultracompact minihalo (UCMH). Their high central den...
From Hubble to Snap Parameters: A Gaussian Process Reconstruction: By using recent $H(z)$ and SNe Ia data, we reconstruct the evolution of kinematic parameters $H(z)$, $q(z)$, jerk and snap, using a model-independent, non-parametric method, namely, the Gaussian Processes. Throughout the present analysis, we have allowe...
Discovery of large-scale diffuse radio emission and of a new galaxy cluster in the surroundings of MACSJ0520.7-1328: We report the discovery of large-scale diffuse radio emission South-East of the galaxy cluster MACS J0520.7-1328, detected through high sensitivity Giant Metrewave Radio Telescope 323 MHz observations....
Samples and statistics of CSS and GPS sources: Several samples have been proposed in the last years in order to study the properties of intrinsically small sources. In this paper, we review the properties of the main samples that are currently available, both selected on the basis of spectral index and of morphology. A...
Fuzzy Dark Matter and the 21cm Power Spectrum: We model the 21cm power spectrum across the Cosmic Dawn and the Epoch of Reionization (EoR) in fuzzy dark matter (FDM) cosmologies. The suppression of small mass halos in FDM models leads to a delay in the onset redshift of these epochs relative to cold dark matter (CDM) s...
The Effect of the Peculiar Motions of the Lens, Source and the Observer on the Gravitational Lensing Time Delay: An intervening galaxy acts as a gravitational lens and produces multiple images of a single source such as a remote galaxy. Galaxies have peculiar speeds in addition to the bulk motion arising due to the e...
Renormalization-Group Running Induced Cosmic Inflation: As a contribution to a viable candidate for a standard model of cosmology, we here show that pre-inflationary quantum fluctuations can provide a scenario for the long-sought initial conditions for the inflaton field. Our proposal is based on the assumption that at...
Mergers, AGN, and 'Normal' Galaxies: Contributions to the Distribution of Star Formation Rates and Infrared Luminosity Functions: We use a novel method to predict the contribution of normal star-forming galaxies, merger-induced bursts, and obscured AGN, to IR luminosity functions (LFs) and global SFR densities. We us...
Dark energy and matter interacting scenario can relieve $H_0$ and $S_8$ tensions: We consider a new cosmological model (named $\tilde\Lambda$CDM) in which the vacuum energy interacts with matter and radiation, and test this model using the current cosmological observations. Using the CMB+BAO+SN (CBS) data set to cons...
The virialization density of peaks with general density profiles under spherical collapse: We calculate the non-linear virialization density, $\Delta_c$, of halos under spherical collapse from peaks with an arbitrary initial and final density profile. This is in contrast to the standard calculation of $\Delta_c$ whic...
The H alpha Galaxy Survey. VIII. Close companions and interactions, and the definition of starbursts: (Shortened) We consider the massive star formation properties, radial profiles, and atomic gas masses of those galaxies in our H alpha Galaxy Survey, a representative sample of the local Universe of 327 disk galaxies...
Three-dimensional Keplerian orbit-superposition models of the nucleus of M31: We present three-dimensional eccentric disc models of the nucleus of M31, modelling the disc as a linear combination of thick rings of massless stars orbiting in the potential of a central black hole. Our models are nonparametric generalisa...
Polarimetric imaging with the GMRT: We present the first set of polarimetric images made with the GMRT. These were obtained as part of the program to commission the polarization mode at the telescope. We find that the instrumental polarization leakage at the GMRT varies with frequency. It is hence necessary to solve fo...
The Gemini Cluster Astrophysics Spectroscopic Survey (GCLASS): The Role of Environment and Self-Regulation in Galaxy Evolution at z ~ 1: We evaluate the effects of environment and stellar mass on galaxy properties at 0.85 < z < 1.20 using a 3.6um-selected spectroscopic sample of 797 cluster and field galaxies drawn f...
Studying Inflation with Future Space-Based Gravitational Wave Detectors: Motivated by recent progress in our understanding of the $B$-mode polarization of cosmic microwave background (CMB), which provides important information about the inflationary gravitational waves (IGWs), we study the possibility to acquire inform...
Radio Planetary Nebulae in the Magellanic Clouds: We report the extragalactic radio-continuum detection of 15 planetary nebulae (PNe) in the Magellanic Clouds (MCs) from recent Australia Telescope Compact Array+Parkes mosaic surveys. These detections were supplemented by new and high resolution radio, optical and IR ob...
Death and Serious Injury by Dark Matter: Macroscopic dark matter refers to a variety of dark matter candidates that would be expected to (elastically) scatter off of ordinary matter with a large geometric cross-section. A wide range of macro masses $M_X$ and cross-sections $\sigma_X$ remain unprobed. We show that over ...
The Contribution from Scattered Light to Quasar Galaxy Hosts: We present models representing the scattering of quasar radiation off free electrons and dust grains in geometries that approximate the structure of quasar host galaxies. We show that, for reasonable assumptions, scattering alone can easily produce ratios of...
Extragalactic millimeter-wave sources in South Pole Telescope survey data: source counts, catalog, and statistics for an 87 square-degree field: We report the results of an 87 square-degree point-source survey centered at R.A. 5h30m, decl. -55 deg. taken with the South Pole Telescope (SPT) at 1.4 and 2.0 mm wavelengt...
Revealing the galaxy-halo connection in IllustrisTNG: We use the IllustrisTNG (TNG) simulations to explore the galaxy-halo connection as inferred from state-of-the-art cosmological, magnetohydrodynamical simulations. With the high mass resolution and large volume achieved by combining the 100 Mpc (TNG100) and 300 Mpc (...
Self-Similar Dynamical Relaxation of Dark Matter Halos in an Expanding Universe: We investigate the structure of cold dark matter halos using advanced models of spherical collapse and accretion in an expanding Universe. These base on solving time-dependent equations for the moments of the phase-space distribution fun...
KiDS-1000 catalogue: Weak gravitational lensing shear measurements: We present weak lensing shear catalogues from the fourth data release of the Kilo-Degree Survey, KiDS-1000, spanning 1006 square degrees of deep and high-resolution imaging. Our `gold-sample' of galaxies, with well-calibrated photometric redshift distr...
Consistent and simultaneous modelling of galaxy clustering and galaxy-galaxy lensing with Subhalo Abundance Matching: The spatial distribution of galaxies and their gravitational lensing signal offer complementary tests of galaxy formation physics and cosmology. However, their synergy can only be fully exploited if b...
CosmicNet I: Physics-driven implementation of neural networks within Boltzmann-Einstein solvers: Einstein-Boltzmann Solvers (EBSs) are run on a massive scale by the cosmology community when fitting cosmological models to data. We present a new concept for speeding up such codes with neural networks. The originality o...
A tale of dark matter capture, sub-dominant WIMPs, and neutrino observatories: Weakly Interacting Massive Particles (WIMPs), which are among the best motivated dark matter (DM) candidates, could make up all or only a fraction of the total DM budget. We consider a scenario in which WIMPs are a sub-dominant DM componen...
Long-term variability of extragalactic radio sources in the Planck Early Release Compact Source Catalogue: Combining measurements taken using the Wilkinson Microwave Anisotropy Probe (WMAP) from 2001 to 2008 with measurements taken using Planck from 2009 to 2010, we investigate the long-term flux density variability ...
Platonic topology and CMB fluctuations: Homotopy, anisotropy, and multipole selection rules: The Cosmic Microwave Background CMB originates from an early stage in the history of the universe. Observed low multipole contributions of CMB fluctuations have motivated the search for selection rules from the underlying top...
The stellar mass structure of massive galaxies from z=0 to z=2.5; surface density profiles and half-mass radii: We present stellar mass surface density profiles of a mass-selected sample of 177 galaxies at 0.5 < z < 2.5, obtained using very deep HST optical and near-infrared data over the GOODS-South field, including...
ScamPy -- A sub-halo clustering & abundance matching based Python interface for painting galaxies on the dark matter halo/sub-halo hierarchy: We present a computational framework for "painting" galaxies on top of the Dark Matter Halo/Sub-Halo hierarchy obtained from N-body simulations. The method we use is based on t...
Hyperluminous infrared galaxies from IIFSCz: We present a catalogue of 179 hyperluminous infrared galaxies (HLIRGs) from the Imperial IRAS-FSS Redshift (IIFSCz) Catalogue. Of the 92 with detections in at least two far infrared bands, 62 are dominated by an M82-like starburst, 22 by an Arp220-like starburst and 8 by an ...
Gravitational redshift in the void-galaxy cross-correlation function in redshift space: We construct an analytic model for the void-galaxy cross-correlation function that enables theoretical predictions of the dipole signal produced dominantly by the gravitational redshift within voids for the first time. By extendin...
Radiation and energy release in a background field of axion-like dark matter: We find that a fuzzy dark matter background and the mG scale magnetic field in the galactic center can give rise to a radiation with a very large energy release. The frequency of the radiation field is the same as the frequency of the oscil...
Density profiles and voids in modified gravity models: We study the formation of voids in a modified gravity model in which gravity is generically stronger or weaker on large scales. We show that void abundances provide complementary information to halo abundances: if normalized to the CMB, models with weaker large-sca...
A 22-year Southern Sky Survey for Transient and Variable Radio Sources using the Molonglo Observatory Synthesis Telescope: We describe a 22-year survey for variable and transient radio sources, performed with archival images taken with the Molonglo Observatory Synthesis Telescope (MOST). This survey covers $2775 \uni...
Secular evolution of galaxies and galaxy clusters in decaying dark matter cosmology: If the dark matter sector in the universe is composed by metastable particles, galaxies and galaxy clusters are expected to undergo significant secular evolution from high to low redshift. We show that the decay of dark matter, with ...
A simulation-based inference pipeline for cosmic shear with the Kilo-Degree Survey: The standard approach to inference from cosmic large-scale structure data employs summary statistics that are compared to analytic models in a Gaussian likelihood with pre-computed covariance. To overcome the idealising assumptions ab...
Statistics of cosmic density profiles from perturbation theory: The joint probability distribution function (PDF) of the density within multiple concentric spherical cells is considered. It is shown how its cumulant generating function can be obtained at tree order in perturbation theory as the Legendre transform of a ...
Correlation and time delays of the X-ray and optical emission of the Seyfert Galaxy NGC3783: We present simultaneous X-ray and optical B and V band light curves of the Seyfert Galaxy NGC3783 spanning 2 years. The flux in all bands is highly variable and the fluctuations are significantly correlated. As shown before b...
The Rethermalizing Bose-Einstein Condensate of Dark Matter Axions: The axions produced during the QCD phase transition by vacuum realignment, string decay and domain wall decay thermalize as a result of their gravitational self-interactions when the photon temperature is approximately 500 eV. They then form a Bose-Eins...
How much a galaxy knows about its large-scale environment?: An information theoretic perspective: The small-scale environment characterized by the local density is known to play a crucial role in deciding the galaxy properties but the role of large-scale environment on galaxy formation and evolution still remain a le...
Constraints on neutrino masses from Lyman-alpha forest power spectrum with BOSS and XQ-100: We present constraints on masses of active and sterile neutrinos. We use the one-dimensional Ly$\alpha$-forest power spectrum from the Baryon Oscillation Spectroscopic Survey (BOSS) of the Sloan Digital Sky Survey (SDSS-III) a...
Searching for axion-like particles through CMB birefringence from string-wall networks: Axion-like particles (ALPs) can form a network of cosmic strings and domain walls that survives after recombination and leads to anisotropic birefringence of the cosmic microwave background (CMB). In addition to studying cosmic st...
Towards distinguishing variants of non-minimal inflation: We study models of inflation where the scalar field $\phi$ that drives inflation is coupled non-minimally to gravity via $\xi \phi^2 R$, or where the gravity sector is enlarged by an $R^2$ term. We consider the original Higgs inflation, Starobinsky inflation, an...
The Faint End of the Luminosity Function and Low Surface Brightness Galaxies: SHELS (Smithsonian Hectospec Lensing Survey) is a dense redshift survey covering a 4 square degree region to a limiting R = 20.6. In the construction of the galaxy catalog and in the acquisition of spectroscopic targets, we paid careful att...
Testing the coincidence problem with strong gravitational lens, Type Ia supernovae and Hubble parameter observational data: In this paper, we use three different kinds of observational data, including 130 strong gravitational lensing (SGL) systems, type Ia supernovae (SNeIa: Pantheon and Union2.1) and 31 Hubble param...
Cosmological constraints from HSC survey first-year data using deep learning: We present cosmological constraints from the Subaru Hyper Suprime-Cam (HSC) first-year weak lensing shear catalogue using convolutional neural networks (CNNs) and conventional summary statistics. We crop 19 $3\times3\,\mathrm{{deg}^2}$ sub-...
Deep learning reconstruction of the large scale structure of the Universe from luminosity distance observations: Supernovae Ia (SNe) can provide a unique window on the large scale structure (LSS) of the Universe at redshifts where few other observations are available, by solving the inversion problem (IP) consisting ...
Premature Black Hole Death of Population III Stars by Dark Matter: Population III stars were the first generation of stars, formed in minihalos of roughly primordial element abundances, and therefore metal-free. They are thought to have formed at the cores of dense dark matter clouds. Interactions between baryons and d...
Machine Learning Classification to Identify Catastrophic Outlier Photometric Redshift Estimates: We present results of using a basic binary classification neural network model to identify likely catastrophic outlier photometric redshift estimates of individual galaxies, based only on the galaxies' measured photometri...
The 21-cm bispectrum from neutral hydrogen islands at z < 6: Spatial variations in the Lyman-$\alpha$ forest opacity at $z<6$ seem to require a late end to cosmic reionization. In this picture, the universe contains neutral hydrogen 'islands' of up to 100 cMpc$/h$ in extent down to redshifts as low as $z\sim 5.3$. This...
Structure formation simulations with momentum exchange: alleviating tensions between high-redshift and low-redshift cosmological probes: Persisting tensions between the cosmological constraints derived from low-redshift probes and the ones obtained from temperature and polarisation anisotropies of the Cosmic Microwav...
Science with the space-based interferometer eLISA. III: Probing the expansion of the Universe using gravitational wave standard sirens: We investigate the capability of various configurations of the space interferometer eLISA to probe the late-time background expansion of the universe using gravitational wave standar...
Gravitational Wave signatures of inflationary models from Primordial Black Hole Dark Matter: Primordial Black Holes (PBH) could be the cold dark matter of the universe. They could have arisen from large (order one) curvature fluctuations produced during inflation that reentered the horizon in the radiation era. At re...
Gravitational Lensing Signatures of Axion Dark Matter Minihalos in Highly Magnified Stars: Axions are a viable candidate for Cold Dark Matter (CDM) which should generically form minihalos of sub-planetary masses from white-noise isocurvature density fluctuations if the Peccei-Quinn phase transition occurs after infla...
Constraints of the equation of state of dark energy from current and future observational data by piecewise parametrizations: The model-independent piecewise parametrizations (0-spline, linear-spline and cubic-spline) are used to estimate constraints of equation of state of dark energy ($w_{de}$) from current observa...
A major galaxy cluster merger caught by eROSITA: weak lensing mass distribution and kinematic description: We present the weak lensing mass distribution of a triple merging cluster candidate at $z_{\rm photo}\sim 0.36$ belonging to a supercluster recently discovered during the eROSITA Performance Verification phase. ...
The Absolute Magnitudes of Type Ia Supernovae in the Ultraviolet: We examine the absolute magnitudes and light-curve shapes of 14 nearby(redshift z = 0.004--0.027) Type Ia supernovae (SNe~Ia) observed in the ultraviolet (UV) with the Swift Ultraviolet/Optical Telescope. Colors and absolute magnitudes are calculated usi...
Resolving the problem of galaxy clustering on small scales: any new physics needed?: Galaxy clustering sets strong constraints on the physics governing galaxy formation and evolution. However, most current models fail to reproduce the clustering of low-mass galaxies on small scales ($r<1Mpc/h$). In this paper we stud...
Science with CMB spectral distortions: The measurements of COBE/FIRAS have shown that the CMB spectrum is extremely close to a perfect blackbody. There are, however, a number of processes in the early Universe that should create spectral distortions at a level which is within reach of present day technology. In this ta...
Constraints on the Hubble constant from Supernova Refsdal's reappearance: The gravitationally lensed Supernova Refsdal appeared in multiple images, produced through gravitational lensing by a massive foreground galaxy cluster. After the supernova appeared in 2014, lens models of the galaxy cluster predicted an addition...
Spin Alignment in Analogues of The Local Sheet: Tidal torque theory and simulations of large scale structure predict spin vectors of massive galaxies should be coplanar with sheets in the cosmic web. Recently demonstrated, the giants (K$_{s}$ $\leq$ -22.5 mag) in the Local Volume beyond the Local Sheet have spin vector...
Stellar sources of dust in the high redshift Universe: With the aim of investigating whether stellar sources can account for the >10^8 Msun dust masses inferred from mm/sub-mm observations of samples of 5<z<6.4 quasars,we develop a chemical evolution model which follows the evolution of metals and dust on the stellar c...
Mass bound for primordial black hole from trans-Planckian censorship conjecture: The recently proposed trans-Planckian censorship conjecture (TCC) imposes a strong constraint on the inflationary Hubble scale, of which the upper bound could be largely relaxed by considering a noninstantaneous reheating history. In thi...
Correcting for peculiar velocities of Type Ia Supernovae in clusters of galaxies: Type Ia Supernovae (SNe Ia) are widely used to measure the expansion of the Universe. To perform such measurements the luminosity and cosmological redshift ($z$) of the SNe Ia have to be determined. The uncertainty on $z$ includes an un...
Primordial black holes from sound speed resonance in the inflaton-curvaton mixed scenario: We study sound speed resonance (SSR) mechanism for primordial black hole (PBH) formation in an early universe scenario with inflaton and curvaton being mixed. In this scenario, the total primordial density perturbations can be ...
Investigating the large-scale environment of wide-angle tailed radio galaxies in the local Universe: We present a statistical analysis of the large-scale (up to 2 Mpc) environment of an homogeneous and complete sample, both in radio and optical selection, of wide-angle tailed radio galaxies (WATs) in the local Univer...
Forty Years of Research on Isolated Galaxies: Isolated galaxies have not been a hot topic over the past four decades. This is partly due to uncertainties about their existence. Are there galaxies isolated enough to be interesting? Do they exist in sufficient numbers to be statistically useful? Most attempts to compile ...
Exploring the inner region of Type 1 AGNs with the Keck interferometer: The exploration of extragalactic objects with long-baseline interferometers in the near-infrared has been very limited. Here we report successful observations with the Keck interferometer at K-band (2.2 um) for four Type 1 AGNs, namely NGC4151, Mrk...
Cosmological Simulations for Combined-Probe Analyses: Covariance and Neighbour-Exclusion Bias: We present a public suite of weak lensing mock data, extending the Scinet Light Cone Simulations (SLICS) to simulate cross-correlation analyses with different cosmological probes. These mocks include KiDS-450- and LSST-like...
Arc Statistics: The existence of an arc statistics problem was at the center of a strong debate in the last fifteen years. With the aim to clarify if the optical depth for giant gravitational arcs by galaxy clusters in the so called concordance model is compatible with observations, several studies were carried out whi...
BAO scale inference from biased tracers using the EFT likelihood: The physical scale corresponding to baryon acoustic oscillations (BAO), the size of the sound horizon at recombination, is precisely determined by CMB experiments. Measuring the apparent size of the BAO scale imprinted in the clustering of galaxies gives...
The GALEX Arecibo SDSS Survey V: The Relation between the HI Content of Galaxies and Metal Enrichment at their Outskirts: We have obtained long-slit spectra of 174 star-forming galaxies with stellar masses greater than 10^10 M_\odot from the GALEX Arecibo SDSS (GASS) survey. These galaxies have both HI and H_2 mass m...
Exploring interacting holographic dark energy in a perturbed universe with parameterized post-Friedmann approach: The model of holographic dark energy in which dark energy interacts with dark matter is investigated in this paper. In particular, we consider the interacting holographic dark energy model in the context ...
On primordial black holes from an inflection point: Recently, it has been claimed that inflationary models with an inflection point in the scalar potential can produce a large resonance in the power spectrum of curvature perturbation. In this paper however we show that the previous analyses are incorrect. The reason is...
Illuminating the Darkest Galaxies: Low luminosity dwarf galaxies provide stringent constraints on the nature of dark matter. Establishing these constraints depends on precise kinematic measurements of individual stars. In this overview for non-specialists, we describe current and future prospects for three unique tests...
The Impact of Assuming Flatness in the Determination of Neutrino Properties from Cosmological Data: Cosmological data have provided new constraints on the number of neutrino species and the neutrino mass. However these constraints depend on assumptions related to the underlying cosmology. Since a correlation is expec...
Inflation with shallow dip and primordial black holes: Primordial black holes may arise through ultra slow-roll inflation. In this work we study a toy model of ultra slow-roll inflation with a shallow dip. The ultra slow-roll stage enhances the curvature perturbations and thus the primordial scalar power spectrum. We a...
Dark Matter with N-Body Numerical Simulations: The development of numerical N -body simulations have allowed to study formation process and evolution of galaxies at different scales. This paper presents the fundamental concepts of N-body systems applied to the cosmological evolution of the $\Lambda$-Cold Dark Matter ($...
Could fresh lava be (warm) dark matter?: Dark matter models can be classified according to their impact on the properties of galaxies, including cold dark matter (CDM), warm dark matter (WDM), self-interacting dark matter (SIDM) and fuzzy dark matter (FDM). In celebration of April Fool's Day, and also of the 1-year ann...
Separate Universe Simulations: The large-scale statistics of observables such as the galaxy density are chiefly determined by their dependence on the local coarse-grained matter density. This dependence can be measured directly and efficiently in N-body simulations by using the fact that a uniform density perturbation ...
Thermal abundance of non-relativistic relics with Sommerfeld enhancement: We propose an analytic treatment for computing the relic abundances of non-relativistic particles whose annihilation rate at chemical decoupling is increased by Sommerfeld enhancement. We find approximate rational functions that closely fit the t...
The Zurich Environmental Study of Galaxies in Groups along the Cosmic Web. III. Galaxy Photometric Measurements and the Spatially-Resolved Color Properties of Early- and Late-Type Satellites in Diverse Environments: We present photometric measurements for the galaxies - and when possible their bulges and disks - in...
Inferring the redshift of more than 150 GRBs with a Machine Learning Ensemble model: Gamma-Ray Bursts (GRBs), due to their high luminosities are detected up to redshift 10, and thus have the potential to be vital cosmological probes of early processes in the universe. Fulfilling this potential requires a large sample...
Unbiased clustering estimates with the DESI fibre assignment: The Emission Line Galaxy survey made by the Dark Energy Spectroscopic Instrument (DESI) survey will be created from five passes of the instrument on the sky. On each pass, the constrained mobility of the ends of the fibres in the DESI focal plane means that ...