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Low-mass dwarf galaxies are expected to reside within dark matter haloes that have a pristine, `cuspy' density profile within their stellar half-light radii. This is because they form too few stars to significantly drive dark matter heating…

The history of reionization reflects the cumulative injection of ionizing photons by sources and the absorption of ionizing photons by sinks. The latter process is traditionally described in terms of a "clumping factor" which encodes the…

Cosmology and Nongalactic Astrophysics · Physics 2024-07-12 Frederick B. Davies , Sarah E. I. Bosman , Steven R. Furlanetto

We present the first suite of cosmological N-body simulations that simultaneously include the effects of two different and theoretically independent extensions of the standard $\Lambda$CDM cosmological scenario - namely an $f(R)$ theory of…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-17 Marco Baldi , Francisco Villaescusa-Navarro , Matteo Viel , Ewald Puchwein , Volker Springel , Lauro Moscardini

Combing the three-dimensional radiative transfer (RT) calculation and cosmological SPH simulations, we study the escape fraction of ionizing photons (f_esc) of high-redshift galaxies at z=3-6. Our simulations cover the halo mass range of…

Cosmology and Nongalactic Astrophysics · Physics 2012-01-13 Hidenobu Yajima , Jun-Hwan Choi , Kentaro Nagamine

Understanding cosmic reionization requires the identification and characterization of early sources of hydrogen-ionizing photons. The 2012 Hubble Ultra Deep Field (UDF12) campaign has acquired the deepest infrared images with the Wide Field…

The escape fraction of Lyman continuum photons (fesc(LyC)) is the last key unknown in our understanding of cosmic reionization. Directly estimating the escape fraction (fesc) of ionizing photons in the epoch of reionization (EoR) is…

Probing the growth of structure from the epoch of hydrogen recombination to the formation of the first stars and galaxies is one of the most important uncharted areas of observational cosmology. Far-IR spectroscopy covering $\lambda$…

The mass-sheet degeneracy is a well-known problem in gravitational lensing which limits our capability to infer astrophysical lens properties or cosmological parameters from observations. As the number of gravitational wave observations…

Cosmology and Nongalactic Astrophysics · Physics 2021-07-07 Paolo Cremonese , Jose María Ezquiaga , Vincenzo Salzano

We investigate reheating of the universe by early formation of stars and quasars in the hierarchical clustering scheme of cold dark matter scenario, with perturbation fluctuations normalized by the COBE data. It is found that ionizing uv…

Astrophysics · Physics 2015-06-24 M. Fukugita , M. Kawasaki

We compare model results from a semi-analytic (merger-tree based) framework for high-redshift (z ~ 5-20) galaxy formation against reionization indicators, including the Planck electron scattering optical depth and the ionizing photon…

Cosmology and Nongalactic Astrophysics · Physics 2017-02-22 Pratika Dayal , Tirthankar Roy Choudhury , Volker Bromm , Fabio Pacucci

The kinematics and elemental abundances of resolved stars in the nearby Universe can be used to infer conditions at high redshift, trace how galaxies evolve and constrain the nature of dark matter. This approach is complementary to direct…

Astrophysics of Galaxies · Physics 2010-07-20 Rosemary F. G. Wyse

We make a number of comments regarding modeling degeneracies in strong lensing measurements of the Hubble parameter $H_0$. The first point concerns the impact of weak lensing associated with different segments of the line of sight. We show…

Cosmology and Nongalactic Astrophysics · Physics 2022-10-25 Luca Teodori , Kfir Blum , Emanuele Castorina , Marko Simonović , Yotam Soreq

Early results from the JWST observations have reported a surprisingly high number of UV-bright galaxies at $z \geq 10$, which appears to challenge the theoretical predictions from standard galaxy formation models in the $\Lambda$CDM…

Astrophysics of Galaxies · Physics 2024-07-30 Anirban Chakraborty , Tirthankar Roy Choudhury

Searches for dark matter decaying into photons constrain its lifetime to be many orders of magnitude larger than the age of the Universe. A corollary statement is that the abundance of any particle that can decay into photons over…

High Energy Physics - Phenomenology · Physics 2022-12-14 Kevin Langhoff , Nadav Joseph Outmezguine , Nicholas L. Rodd

The recent discovery of dusty galaxies well into the Epoch of Reionization (redshift $z>6$) poses challenging questions about the properties of the interstellar medium in these pristine systems. By combining state-of-the-art hydrodynamic…

Astrophysics of Galaxies · Physics 2018-04-04 C. Behrens , A. Pallottini , A. Ferrara , S. Gallerani , L. Vallini

The sources that reionized the universe are still unknown, but likely candidates are faint but numerous galaxies. In this paper we present results from running a high resolution, uniform volume simulation, the Vulcan, to predict the number…

Astrophysics of Galaxies · Physics 2017-05-10 Lauren Anderson , Fabio Governato , Michael Karcher , Tom Quinn , James Wadsley

We explore scenarios for reionizing the intergalactic medium with low galaxy ionizing photon escape fractions. We combine simulation-based halo-mass dependent escape fractions with an extrapolation of the observed galaxy rest-ultraviolet…

Searches for new physics typically rely on proton-proton collisions, where isolated mass bumps are the primary signatures. However, when a new particle is nearly degenerate in mass with a known Standard Model resonance, it can be partially…

High Energy Physics - Phenomenology · Physics 2026-05-14 Yi Yang

We use new studies of the cosmic evolution of star-forming galaxies to estimate the production rate of ionizing photons from hot, massive stars at low and intermediate redshifts. The luminosity function of blue galaxies in the Canada-France…

Astrophysics · Physics 2015-06-24 E. Giallongo , A. Fontana , P. Madau

An intriguing possibility for the dark sector of our universe is that the dark matter particle could interact with a dark radiation component. If the non-gravitational interactions of the dark matter and dark radiation species with Standard…

Cosmology and Nongalactic Astrophysics · Physics 2018-09-05 Subinoy Das , Rajesh Mondal , Vikram Rentala , Srikanth Suresh
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