Latest in astro-ph.co

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Measuring $H_0$ in PTA with gravitational wavesAug 22 2019Pulsar Timing Arrays have yet to find convincing evidence of gravitational waves. Some time ago it was pointed out by one of the authors that a dramatic enhancement of the signal would take place for particular values of the angle subtended by the source ... More
Galaxy number counts at second order: an independent approachAug 22 2019Next generation surveys will be capable of determining cosmological parameters beyond percent level.To match this precision, theoretical descriptions should look beyond the linear perturbations to approximate the observables in large scale structure. ... More
Revisiting the expected Micro-X signal from the 3.5 keV lineAug 22 2019One of the future instruments to resolve the origin of the unidentified 3.5 keV emission line is the Micro-X sounding rocket telescope. According to the estimate made in 2015, Micro-X will be able to detect on average about 18.2 photons from the 3.5 keV ... More
Nonlinear Reconstruction of the Velocity FieldAug 22 2019We propose a new velocity reconstruction method based on the displacement estimation by recently developed methods. The velocity is first reconstructed by transfer functions in Lagrangian space and then mapped into Eulerian space. High resolution simulations ... More
Delensing Degree-Scale $B$-Mode Polarization with High-Redshift Line Intensity MappingAug 21 2019Cosmic microwave background (CMB) experiments that constrain the tensor-to-scalar ratio $r$ are now approaching the sensitivity at which delensing---removing the $B$ modes induced by the gravitational lensing of large-scale structure---is necessary. We ... More
Bias to CMB lensing from lensed foregroundsAug 21 2019Extragalactic foregrounds are known to constitute a limiting systematic in temperature-based CMB lensing with AdvACT, SPT-3G, Simons Observatory and CMB S4. Furthermore, since these foregrounds are emitted at cosmological distances, they are also themselves ... More
Parametrizations for tests of gravityAug 21 2019With the increasing wealth of high-quality astronomical and cosmological data and the manifold departures from General Relativity in principle conceivable, the development of generalized parametrization frameworks that unify gravitational models and cover ... More
Reconstructing simulated CMB polarization power spectra with the Analytical Blind Separation methodAug 21 2019The Analytical Blind Separation (ABS) method is dedicated to extract the CMB signal from its contaminants without any prior information about foregrounds. In this study, we apply the ABS method to simulated polarization sky maps in order to test its ability ... More
Inflationary Phenomenology of Einstein Gauss-Bonnet Gravity Compatible with GW170817Aug 20 2019In this work we shall study Einstein Gauss-Bonnet theories and we investigate when these can have their gravitational wave speed equal to the speed of light, which is unity in natural units, thus becoming compatible with the striking event GW170817. We ... More
BASILISK: Bayesian Hierarchical Inference of the Galaxy-Halo Connection using Satellite Kinematics--I. Method and ValidationAug 20 2019We present a Bayesian hierarchical inference formalism (Basilisk) to constrain the galaxy-halo connection using satellite kinematics. Unlike traditional methods, Basilisk does not resort to stacking the kinematics of satellite galaxies in bins of central ... More
Some physical implications of regularization ambiguities in SU(2) gauge-invariant loop quantum cosmologyAug 20 2019The way physics of loop quantum gravity is affected by the underlying quantization ambiguities is an open question. We address this issue in the context of loop quantum cosmology using gauge-covariant fluxes. Consequences are explored for two choices ... More
Origin Of Tidal Structures In Modified GravityAug 20 2019The missing mass problem has not been solved decisively yet. Observations show that if gravity is to be modified, then the MOND theory is its excellent approximation on galactic scales. MOND suggests an adjustments of the laws of physics in the limit ... More
Mapping Large-Scale-Structure Evolution over Cosmic TimesAug 20 2019This paper outlines the science case for line-intensity mapping with a space-borne instrument targeting the sub-millimeter (microwaves) to the far-infrared (FIR) wavelength range. Our goal is to observe and characterize the large-scale structure in the ... More
A new probe of Axion-Like Particles: CMB polarization distortions due to cluster magnetic fieldsAug 20 2019We propose using the upcoming Cosmic Microwave Background (CMB) ground based experiments to detect the signal of ALPs (Axion like particles) interacting with magnetic fields in galaxy clusters. The conversion between CMB photons and ALPs in the presence ... More
Particle acceleration in a nearby galaxy cluster pair: the role of cluster dynamicsAug 20 2019Diffuse radio emission associated with the intra-cluster medium (ICM) is observed in a number of merging galaxy clusters. It is currently believed that in mergers a fraction of the kinetic energy is channeled into non-thermal components, such as turbulence, ... More
Predictions for the diffuse cosmic dipole at radio frequencies from reionization imprintsAug 20 2019The cosmological reionization can be studied in the radio through the tomographic view offered by the redshifted 21-cm line and the integrated information carried out by the diffuse free-free emission, coupled to the Comptonization distortion, relevant ... More
PICO: Probe of Inflation and Cosmic OriginsAug 20 2019The Probe of Inflation and Cosmic Origins (PICO) is a proposed probe-scale space mission consisting of an imaging polarimeter operating in frequency bands between 20 and 800 GHz. We describe the science achievable by PICO, which has sensitivity equivalent ... More
Mass-Temperature relation in $Λ$CDM and modified gravityAug 20 2019We derive the mass-temperature relation using an improved top-hat model and a continuous formation model which takes into account the effects of the ordered angular momentum acquired through tidal-torque interaction between clusters, random angular momentum, ... More
Cosmology With Low-Redshift Observations: No Signal For New PhysicsAug 20 2019We analyse various low-redshift cosmological data from Type-Ia Supernova, Baryon Acoustic Oscillations, Time-Delay measurements using Strong-Lensing, $H(z)$ measurements using Cosmic Chronometers and growth measurements from large scale structure observations ... More
Looking for interactions in the cosmological dark sectorAug 20 2019We study observational signatures of non-gravitational interactions between the dark components of the cosmic fluid, which can be either due to creation of dark particles from the expanding vacuum or an effect of the clustering of a dynamical dark energy. ... More
Redshift space distortions in the presence of non-minimally coupled dark matterAug 20 2019In this paper, we fully investigate cosmological scenarios in which dark matter is non-minimally coupled to an extra scalar degree of freedom. The interaction is realized by means of conformal and disformal terms in the transformed gravitational metric. ... More
$L_1$ Trend Filtering: A Modern Statistical Tool for Time-Domain Astronomy and Astronomical SpectroscopyAug 20 2019The problem of estimating a one-dimensional signal possessing mixed degrees of smoothness is ubiquitous in time-domain astronomy and astronomical spectroscopy. For example, in the time domain, an astronomical object may exhibit a smoothly varying intensity ... More
Optimizing galaxy samples for clustering measurements in photometric surveysAug 20 2019When analyzing galaxy clustering in multi-band imaging surveys, there is a trade-off between selecting the largest galaxy samples (to minimize the shot noise) and selecting samples with the best photometric redshift (photo-z) precision, which generally ... More
Pattern of perturbations from a coherent quantum inflationary horizonAug 19 2019It is proposed that a coherent quantum inflationary horizon produces relic primordial curvature perturbations with a distinctive pattern of nonlocal correlations. A holographic quantum model is used to derive an uncertainty for space-time localization ... More
Oscillating scalar fields and the Hubble tension: a resolution with novel signaturesAug 19 2019We present a detailed investigation of a sub-dominant oscillating scalar field ('early dark energy', EDE) in the context of resolving the Hubble tension. Consistent with earlier work, but without relying on fluid approximations, we find that a scalar ... More
Warm dark matter chills out: constraints on the halo mass function and the free-streaming length of dark matter with 8 quadruple-image strong gravitational lensesAug 19 2019The free-streaming length of dark matter depends on fundamental dark matter physics, and determines the abundance and central densities of dark matter halos on sub-galactic scales. Using the image positions and flux-ratios from eight quadruply-imaged ... More
Reviving Millicharged Dark Matter for 21-cm CosmologyAug 19 2019The existence of millicharged dark matter (mDM) can leave a measurable imprint on 21-cm cosmology through mDM-baryon scattering. However, the minimal scenario is severely constrained by existing cosmological bounds on both the fraction of dark matter ... More
Origin of ultra-light fields during inflation and their suppressed non-GaussianityAug 19 2019We study the structure of multi-field inflation models where the primordial curvature perturbation is able to vigorously interact with an ultra-light isocurvature field -- a massless fluctuation orthogonal to the background inflationary trajectory in ... More
RESPONSE TO Time Modulations and Amplifications in the Axion Search ExperimentsAug 19 2019In this short note we argue why the conclusions made by the authors of arXiv:1908.04675, related to arXiv:1805.05184 and in particular arXiv:1602.03666 given therein, are incorrect. Nevertheless, we think that the advocated Anti-Quark Nuggets are good ... More
Comment on N. Rijal et al. "Measurement of d + 7Be Cross Sections for Big-Bang Nucleosynthesis"Aug 18 2019Rijal, et al. in their recent publication [Phys. Rev. Lett {\bf 122}, 182701 (2019), arXiv:1808.07893], on "Measurement of d + $^7$Be Cross Sections for Big-Bang Nucleosynthesis (BBN)", misrepresent their result, they misrepresent previous work of Parker ... More
Radio continuum emission from local analogs of high-z faint LAEs: Blueberry galaxiesAug 18 2019We present a radio continuum study of a population of extremely young and starburst galaxies, termed as blueberries at ${\sim}$ 1 GHz using the upgraded Giant Metrewave Radio Telescope (uGMRT). We find that their radio-based star formation rate (SFR) ... More
Double dark matter vision: twice the number of compact-source lenses with narrow-line lensing and the WFC3 GrismAug 17 2019The magnifications of compact-source lenses are extremely sensitive to the presence of low mass dark matter halos along the entire sight line from the source to the observer. Traditionally, the study of dark matter structure in compact-source strong gravitational ... More
The model-independent degeneracy-breaking point in cosmological models with interacting Dark Energy and Dark MatterAug 17 2019We study cosmological models with interaction between dark energy (DE) and dark matter (DM). For the interaction term $Q$ in cosmic evolution equations, there is a model-independent degeneracy-breaking (D-B) point when $Q_{1}$ (a part of $Q$) equals to ... More
Perturbation theory approach to predict the covariance matrices of the galaxy power spectrum and bispectrum in redshift spaceAug 17 2019Extending the current standard analysis of the galaxy power spectrum to include the bispectrum represents a significant step towards extracting the full cosmological information from galaxy redshift surveys. In this paper, we predict the covariance matrices ... More
Summary of cosmology with gravitational waves from compact binary coalescencesAug 16 2019GW170817 with its coincident optical counterpart has led to a first "standard siren" measurement of the Hubble constant independent of the cosmological distance ladder. The Schutz "statistical" method, which is expected to work in the absence of uniquely ... More
Gravitational waves, CMB polarization, and the Hubble tensionAug 16 2019The discrepancy between the Hubble parameter inferred from local measurements and that from the cosmic microwave background (CMB) has motivated careful scrutiny of the assumptions that enter both analyses. Here we point out that the location of the recombination ... More
QCD Axion on Hilltop by Phase Shift of $π$Aug 16 2019We show that the initial misalignment angle of the QCD axion (or axion-like particles) can be set very close to $\pi$, if the QCD axion has a mixing with another heavy axion which induces the phase shift $\approx \pi$ after inflation. In the simplest ... More
A gravitational-wave measurement of the Hubble constant following the second observing run of Advanced LIGO and VirgoAug 16 2019This paper presents the gravitational-wave measurement of the Hubble constant $H_0$ using the detections from the first and second observing runs of the Advanced LIGO and Virgo detector network. The presence of the transient electromagnetic counterpart ... More
A gravitational-wave measurement of the Hubble constant following the second observing run of Advanced LIGO and VirgoAug 16 2019Aug 21 2019This paper presents the gravitational-wave measurement of the Hubble constant $H_0$ using the detections from the first and second observing runs of the Advanced LIGO and Virgo detector network. The presence of the transient electromagnetic counterpart ... More
Cosmological Inference using Gravitational Wave Standard Sirens: A Mock Data ChallengeAug 16 2019The detection of gravitational waves from the binary neutron star merger GW170817 alongside its optical counterparts, marked the beginning of gravitational wave cosmology as it allowed for the first constraint onthe Hubble constant $H_0$ using gravitational ... More
Cosmological Inference using Gravitational Wave Standard Sirens: A Mock Data ChallengeAug 16 2019Aug 19 2019The detection of gravitational waves from the binary neutron star merger GW170817, alongside its optical counterpart, marked the beginning of gravitational wave cosmology as it allowed for the first constraint on the Hubble constant $H_0$ using gravitational ... More
Astrophysics and cosmology with a deci-hertz gravitational-wave detector: TianGOAug 16 2019We present the astrophysical science case for a space-based, deci-Hz gravitational-wave (GW) detector. We particularly highlight an ability in inferring a source's sky location, both when combined with a network of ground-based detectors to form a long ... More
A Novel Scheme for Dark Matter Annihilation Feedback in Cosmological SimulationsAug 16 2019We present a new self-consistent method for incorporating dark matter annihilation feedback (DMAF) in cosmological N-body simulations. The power generated by DMAF is evaluated at each dark matter (DM) particle which allows for flexible energy injection ... More
The impact of the observed baryon distribution in haloes on the total matter power spectrumAug 15 2019The interpretation of upcoming weak gravitational lensing surveys depends critically on our understanding of the matter power spectrum on scales $k < 10 h/\mathrm{Mpc}$, where baryonic processes are important. In this paper we study the impact of gas ... More
Inflation in generalized unimodular gravityAug 15 2019The recently suggested generalized unimodular gravity theory, which was originally put forward as a model of dark energy, can serve as a model of cosmological inflation driven by the effective perfect fluid -- the dark purely gravitational sector of the ... More
Einstein-Vlasov Calculations of Structure FormationAug 15 2019We study the dynamics of small inhomogeneities in an expanding universe collapsing to form bound structures using full solutions of the Einstein-Vlasov (N-body) equations. We compare these to standard Newtonian N-body solutions using quantities defined ... More
[OII] emitters in MultiDark-Galaxies and DEEP2Aug 15 2019We use three semi-analytic models (SAMs) of galaxy formation and evolution run on the same $1 h^{-1}$Gpc MultiDark Planck 2 cosmological simulation to investigate the properties of [OII] emission line galaxies over the redshift range $0.6<z<1.2$. We compare ... More
An Improved Distance to NGC 4258 and its Implications for the Hubble ConstantAug 15 2019NGC 4258 is a critical galaxy for establishing the extragalactic distance scale and estimating the Hubble constant (Ho). Water masers in the nucleus of the galaxy orbit about its supermassive black hole, and VLBI observations of their positions, velocities ... More
Cosmological N-body simulations: a challenge for scalable generative modelsAug 15 2019Deep generative models, such as Generative Adversarial Networks (GANs) or Variational Autoencoders have been demonstrated to produce images of high visual quality. However, the existing hardware on which these models are trained severely limits the size ... More
The physical origin of the cosmological constant: continuum limit and the analogy with the Casimir effectAug 15 2019Aug 22 2019In this paper we continue the investigations in \cite{1} concerning the origin of the cosmological constant. First of all, we generalise the results in \cite{1,2} by considering a continuum approximation for a radiation field in a cosmological background. ... More
CMB sky for an off-center observer in a local void I: framework for forecastsAug 15 2019The Universe is not perfectly homogeneous, the large scale structure forms over dense regions and voids. In this paper we consider the possibility that we occupy a special position in our Universe, close to the center of a local under dense region that ... More
Relativistic interpretation and cosmological signature of Milgrom's accelerationAug 15 2019We propose in this letter a relativistic coordinate independent interpretation for Milgrom's acceleration $a_{0}=1.2 \times 10^{-8} \hbox{cm/s}^{2}$ through a geometric constraint obtained from the product of the Kretschmann invariant scalar times the ... More
Quantum Cosmology with many fluids and the choice of cosmological timeAug 14 2019In this work we propose the quantization of a cosmological model describing the primordial universe filled with five barotropic fluids, namely: radiation, dust, vacuum, cosmic strings and domain walls. We intend to identify which fluid is best suited ... More
On the contamination of the global 21~cm signal from polarized foregroundsAug 14 2019Global (i.e. sky-averaged) $21$~cm signal experiments can measure the evolution of the universe from the Cosmic Dawn to the Epoch of Reionization. These measurements are challenged by the presence of bright foreground emission that can be separated from ... More
Prospects and Limitations for Constraining Light Relics with Primordial Abundance MeasurementsAug 14 2019The light relic density affects the thermal and expansion history of the early Universe leaving a number of observable imprints. We focus on the primordial abundances of light elements produced during the process of Big Bang nucleosynthesis which are ... More
High mass and halo resolution from fast low resolution simulationsAug 14 2019Generating mocks for future sky surveys requires large volumes and high resolutions, which is computationally expensive even for fast simulations. In this work we try to develop numerical schemes to calibrate various halo and matter statistics in fast ... More
New Limits on Charged Dark Matter from Large-Scale Coherent Magnetic FieldsAug 14 2019We study the interaction of an electrically charged component of the dark matter with a magnetized galactic interstellar medium (ISM) of (rotating) spiral galaxies. For the observed ordered component of the field, $B\sim \mu$G, we find that the accumulated ... More
Understanding CMB physics through the exploration of exotic cosmological models: a classroom study using CLASSAug 14 2019Every cosmology lecturer these days is confronted with teaching the modern cosmological standard model $\Lambda$CDM, and there are many approaches to do this. However, the danger is imminent that it is presented to students as something set into stone, ... More
Numerical convergence of hydrodynamical simulations of galaxy formation: the abundance and internal structure of galaxies and their cold dark matter haloesAug 14 2019We address the issue of numerical convergence in cosmological smoothed particle hydrodynamics simulations using a suite of runs drawn from the EAGLE project. Our simulations adopt subgrid models that produce realistic galaxy populations at a fiducial ... More
Conformal Gravity and Transformations in the Symmetric Teleparallel FrameworkAug 14 2019Conformal symmetries appear in many parts of physics and play a unique role in exploring the Universe. In this work, we consider the possibility of constructing conformal theories of gravity in the Symmetric Teleparallel Gravity framework, where gravitation ... More
A model-independent determination of the Hubble constant from lensed quasars and supernovae using Gaussian processAug 14 2019Strongly lensed quasar systems with time delay measurements provide "time delay distances", which are a combination of three angular diameter distances and serve as powerful tools to determine the Hubble constant $H_0$. However, current results often ... More
The Kelvin-Helmholtz instability and smoothed particle hydrodynamicsAug 14 2019There has been interest in recent years to assess the ability of astrophysical hydrodynamics codes to correctly model the Kelvin-Helmholtz instability. Smoothed particle hydrodynamics (SPH), in particular, has received significant attention, though there ... More
Tomographic analyses of the CMB lensing and galaxy clustering to probe the linear structure growthAug 13 2019In 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 Galactic Cap u-band Sky Survey (SCUSS), ... More
Fuzzy Dark Matter Soliton Cores around Supermassive Black HolesAug 13 2019We explore the effect of a supermassive black hole (SMBH) on the density profile of a fuzzy dark matter (FDM) soliton core at the centre of a dark matter halo. We numerically solve the Schr\"odinger-Poisson equations, treating the black hole as a gravitational ... More
Development of Hydrogen and Helium Proximity Zones around QuasarsAug 13 2019Increasing evidence suggests that He II proximity profiles in the quasar spectra at z ~ 3 - 4 are sensitive probes of quasar ages. But the development of their H I counterparts is difficult to trace and remains poorly constrained. We compare the UV spectra ... More
Bayesian automated posterior repartitioning for nested samplingAug 13 2019Priors in Bayesian analyses often encode informative domain knowledge that can be useful in making the inference process more efficient. Occasionally, however, priors may be unrepresentative of the parameter values for a given dataset, which can result ... More
The Hubble constant tension with next generation galaxy surveysAug 13 2019The rate at which the universe is expanding today is a fundamental parameter in cosmology which governs our understanding of structure formation and dark energy. However, current measurements of the Hubble constant, $H_0$, show a significant tension ($\sim ... More
Cosmic Textures and Global Monopoles as Seeds for Super-Massive Black HolesAug 13 2019We compute the number density of nonlinear seed fluctuations which have the right number density to be able to explain the presence of one supermassive black hole per galaxy, as a function of redshift. We find that there is an interesting range of symmetry ... More
The probability distribution of 3-D shapes of galaxy clusters from 2-D X-ray imagesAug 13 2019We present a new method to determine the probability distribution of the 3-D shapes of galaxy clusters from the 2-D images using stereology. In contrast to the conventional approach of combining different data sets (such as X-rays, Sunyaev-Zeldovich effect ... More
Kicking gravitational wave detectors with recoiling black holesAug 12 2019Binary black holes emit gravitational radiation with net linear momentum leading to a retreat of the final remnant black hole that can reach up to $\sim5,000$ km/s. Full numerical relativity simulations are the only tool to accurately compute these recoils ... More
Hunting for heavy Dark Matter in the Galactic Center with ground-based Cherenkov telescopesAug 12 2019A TeV scale electroweak particle is a well motivated candidate for the dark matter (DM) of our Universe. Yet such a particle may only be detectable using indirect detection instruments sensitive to TeV-scale gamma rays that can result from dark matter ... More
Euclid preparation: V. Predicted yield of redshift 7<z<9 quasars from the wide surveyAug 12 2019We provide predictions of the yield of $7<z<9$ quasars from the Euclid wide survey, updating the calculation presented in the Euclid Red Book (Laureijs et al. 2011) in several ways. We account for revisions to the Euclid near-infrared filter wavelengths; ... More
Interacting dark energy after the latest Planck, DES, and $H_0$ measurements: an excellent solution to the $H_0$ and cosmic shear tensionsAug 12 2019We examine the most well-studied model featuring non-gravitational interactions between dark matter and dark energy in light of the latest cosmological observations. Our data includes Cosmic Microwave Background (CMB) measurements from the Planck 2018 ... More
Regular bouncing solutions, energy conditions,and the Brans-Dicke theoryAug 12 2019In general, to avoid a singularity in cosmological models involves the introduction of exotic kind of matter fields, for example, a scalar field with negative energy density. In order to have a bouncing solution in classical General Relativity, violation ... More
Derivation of the sterile neutrino Boltzmann equation from quantum kineticsAug 12 2019An extensive, growing body of work has been penned on cosmologies that include one or more sterile neutrinos. Early entries in the literature formulated a Boltzmann-like equation describing sterile-neutrino production in a way that bypasses the numerical ... More
On the cosmological performance of photometric classified supernovae with machine learningAug 12 2019The efficient classification of the different types of Supernova is one of the most important problems of the observational cosmology. Spectroscopic confirmation of most objects in upcoming photometric surveys, such as the Dark Energy Survey and the Large ... More
Big Bang Nucleosynthesis Hunts Chameleon Dark MatterAug 12 2019We study the chameleon field dark matter, dubbed \textit{scalaron}, in $F(R)$ gravity in the Big Bang Nucleosynthesis (BBN) epoch. With an $R^{2}$-correction term required to solve the singularity problem for $F(R)$ gravity, we first find that the scalaron ... More
Big Bang Nucleosynthesis Hunts Chameleon Dark MatterAug 12 2019Aug 20 2019We study the chameleon field dark matter, dubbed \textit{scalaron}, in $F(R)$ gravity in the Big Bang Nucleosynthesis (BBN) epoch. With an $R^{2}$-correction term required to solve the singularity problem for $F(R)$ gravity, we first find that the scalaron ... More
Cosmological comoving behavior of the configurational entropyAug 12 2019It has been shown that a functional dependence of the configurational entropy (CE) density exhibits a cosmological comoving behavior related to the scale parameter, $a$, of the FRW flat universe. Such a circumstantial comoving behavior shows that the ... More
As A Matter of State: The role of thermodynamics in magnetohydrodynamic turbulenceAug 12 2019Turbulence simulations play a key role in advancing the general understanding of the physical properties turbulence and in interpreting astrophysical observations of turbulent plasmas. For the sake of simplicity, however, turbulence simulations are often ... More
Primordial black holes from sound speed resonance in the inflaton-curvaton mixed scenarioAug 11 2019We 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 contributed by the fluctuations ... More
Wide-angle redshift-space distortions at quasi-linear scales: cross-correlation functions from Zel'dovich approximationAug 11 2019Redshift-space distortions (RSD) in galaxy redshift surveys generally break both the isotropy and homogeneity of galaxy distribution. While the former aspect is particularly highlighted as a probe of growth of structure induced by gravity, the latter ... More
The Inflaton Effective Potential for General $ε$Aug 10 2019We develop an analytic approximation for the coincidence limit of a massive scalar propagator in an arbitrary spatially flat, homogeneous and isotropic geometry. We employ this to compute the one loop corrections to the inflaton effective potential from ... More
Improving cosmological parameter estimation with the future 21 cm observation from SKAAug 10 2019Future observations of 21 cm emission from neutral hydrogen survey will become a promising approach to probe the large scale structure of Universe. In this paper, we investigate the impacts of Square Kilometer Array (SKA) 21 cm observation on the estimation ... More
Towards degeneracy breaking of early universe modelsAug 10 2019There are many possibilities of scenarios in the early universe, which can give rise to the same observational signals due to the degeneracy among each other, caused by equivalence under the conformal transformations. In order to break the degeneracy, ... More
The Hubble Hunter's GuideAug 10 2019Measurements of the Hubble constant, and more generally measurements of the expansion rate and distances over the interval $0 < z < 1$, appear to be inconsistent with the predictions of the standard cosmological model ($\Lambda$CDM) given observations ... More
High-resolution Infrared Spectrograph for Exoplanet Characterization with the Keck and Thirty Meter TelescopesAug 09 2019HISPEC (High-resolution Infrared Spectrograph for Exoplanet Characterization) is a proposed diffraction-limited spectrograph for the W.M. Keck Observatory, and a pathfinder for the MODHIS facility project (Multi-Object Diffraction-limited High-resolution ... More
From Primordial Black Holes Abundance to Primordial Curvature Power Spectrum (and back)Aug 09 2019In the model where Primordial Black Holes (PBHs) form from large primordial perturbations, constraints on PBH abundance provide in principle constraints on the primordial curvature power spectrum. This connection however depends necessarily on the details ... More
Time Modulations and Amplifications in the Axion Search ExperimentsAug 09 2019We advocate the idea that the study of time variation in the axion dark matter searches can greatly enhance its discovery potential. We specifically focus on a new mechanism of the axion production suggested recently in [1,2]. Our computations are based ... More
The scaling density of axion stringsAug 09 2019In the QCD axion dark matter scenario with post-inflationary Peccei-Quinn symmetry breaking, the number density of axions, and hence the dark matter density, depends on the length of string per unit volume at cosmic time $t$, by convention written $\zeta/t^2$. ... More
Black Hole RemnantsAug 09 2019We show that in asymptotically free mimetic gravity with limiting curvature the black hole singularity can be resolved and replaced by a static patch of de Sitter space. As a result of Hawking evaporation of these non-singular black holes, there remain ... More
Reheating constraints to modulus mass for single field inflationary modelsAug 09 2019We consider string and supergravity motivated scenarios in which moduli fields dominate the energy density of the Universe in a post-inflationary epoch. For the case of a single light modulus we show that considering the evolution of a specific scale ... More
Modeling the Anisotropic Tidal Effect on the Spin-Spin Correlations of Low-Mass Galactic HalosAug 09 2019The halo spin-spin correlation function, $\eta(r)$, measures how rapidly the strength of the alignments of the spin directions between the neighbor halos change with the separation distance, $r$. The previous model based on the tidal torque theory expresses ... More
The Novel Probes Project -- Tests of Gravity on Astrophysical ScalesAug 09 2019We introduce The Novel Probes Project, an initiative to advance the field of astrophysical tests of the dark sector by creating a forum that connects observers and theorists. This review focuses on tests of gravity and is intended to be of use primarily ... More
Cosmological Birefringence and the Geometric Phase of PhotonsAug 09 2019Regarding axion electrodynamics in the background flat FRW universe, we show that cosmological birefringence arises from an adiabatic noncyclic geometric phase that appears in the quantum state of photons because of their interaction with the axion field. ... More
Resolving Hubble Tension with Quintom Dark Energy ModelAug 09 2019Recent low-redshift observations give value of the present-time Hubble parameter $H_{0}\simeq 74~\rm{km}/{sec}/\rm{Mpc}$, roughly 10\% higher than the predicted value $H_{0}=67.4~\rm{km}/{sec}/\rm{Mpc}$ from Planck's observations of the CMB and the $\Lambda$CDM ... More
Observing Dirac neutrinos in the cosmic microwave backgroundAug 08 2019Planned CMB Stage IV experiments have the potential to measure the effective number of relativistic degrees of freedom in the early Universe, $N_\text{eff}$, with percent-level accuracy. This probes new thermalized light particles and also constrains ... More
Testing Seesaw and Leptogenesis with Gravitational WavesAug 08 2019We present the possibility that the seesaw mechanism with thermal leptogenesis can be tested using the stochastic gravitational background. Achieving neutrino masses consistent with atmospheric and solar neutrino data, while avoiding non-perturbative ... More
Cosmological Instabilities and the Role of Matter Interactions in Dynamical Dark Energy ModelsAug 08 2019We consider cosmological models with a dynamical dark energy field, and study the presence of three types of commonly found instabilities, namely ghost (when fields have negative kinetic energy), gradient (negative momentum squared) and tachyon (negative ... More
Generalized Galileon Scenario Inspires Chaotic InflationAug 08 2019We study chaotic inflation with a Galileon-like self interaction $G(\phi,X)\Box \phi$, where $G(\phi,X)\propto X^{n}$. General conditions required for successful inflation are deduced and discussed from the background and cosmological perturbations under ... More