Publications related to Compact star

White dwarfs as a probe of exceptionally light QCD axions

We study the effects of exceptionally light QCD axions on the stellar configuration of white dwarfs. At finite baryon density, the nonderivative coupling of the axion to nucleons displaces the axion from its invacuum minimum, which implies a reduction of t ...

American Physical Society2024

Weak gravitational lensing measurements of Abell 2744 using JWST and shear measurement algorithm pyRRG-JWST

David Richard Harvey, Richard Massey

We update the publicly available weak lensing shear measurement algorithm pyRRG for the JWST, and apply it to UNCOVER DR1 imaging of galaxy cluster Abell 2744. At short wavelengths (

Oxford Univ Press2024

Direct observations of X-rays produced by upward positive lightning

Marcos Rubinstein, Antonio Sunjerga, Farhad Rachidi-Haeri, Thomas Chaumont

X-rays have been observed in natural downward cloud-to-ground lightning for over 20 years and in rocket-triggered lightning for slightly less. In both cases, this energetic radiation has been detected during the stepped and dart leader phases of downward n ...

Nature Publishing Group2024

A compact approach to higher-resolution resonant inelastic x-ray scattering detection using photoelectrons

Henrik Moodysson Rønnow, Markus Scholz

The detection of inelastically scattered soft x-rays with high energy resolution usually requires large grating spectrometers. Recently, photoelectron spectrometry for analysis of x-rays (PAX) has been rediscovered for modern spectroscopy experiments at sy ...

Iop Publishing Ltd2024

The AGORA High-resolution Galaxy Simulations Comparison Project. V. Satellite Galaxy Populations in a Cosmological Zoom-in Simulation of a Milky Way-Mass Halo

Yves Revaz, Loïc Hausammann, Alessandro Lupi

We analyze and compare the satellite halo populations at z similar to 2 in the high-resolution cosmological zoom-in simulations of a 1012 M circle dot target halo (z = 0 mass) carried out on eight widely used astrophysical simulation codes (Art-I, Enzo, Ra ...

Iop Publishing Ltd2024

SUNBIRD : a simulation-based model for full-shape density-split clustering

Daniel Felipe Forero Sanchez

Combining galaxy clustering information from regions of different environmental densities can help break cosmological parameter degeneracies and access non-Gaussian information from the density field that is not readily captured by the standard two-point c ...

2024

Decay law of magnetic turbulence with helicity balanced by chiral fermions

Kohei Kamada, Jennifer Waltraud Schober

In plasmas composed of massless electrically charged fermions, chirality can be interchanged with magnetic helicity while preserving the total chirality through the quantum chiral anomaly. The decay of turbulent energy in plasmas such as those in the early ...

AMER PHYSICAL SOC2023

Probing compact dark matter objects with microlensing in gravitationally lensed quasars

Frédéric Courbin, Eric Gérard Guy Paic, Hung-Hsu Chan, Martin Raoul Robert Millon, Petra Awad

The microlensing signal in the light curves of gravitationally lensed quasars can shed light on the dark matter (DM) composition in their lensing galaxies. Here, we investigate a sample of six lensed quasars from the most recent and best COSMOGRAIL observa ...

EDP SCIENCES S A2023

The formation of the faintest galaxies in cosmological simulations: from the impact of primordial magnetic fields to the metal enrichment of present day dwarfs by first stars

Mahsa Sanati

In the theory of the bottom-up assembly of cosmic structures, one of the main challenges is to connect the smallest, most inconspicuous galaxies we observe today to the building blocks of more massive galaxies such as our own, the Milky Way. Do these so-ca ...

EPFL2023

Finite-resolution Deconvolution of Multiwavelength Imaging of 20,000 Galaxies in the COSMOS Field: The Evolution of Clumpy Galaxies over Cosmic Time

Pascale Jablonka

Compact star-forming clumps observed in distant galaxies are often suggested to play a crucial role in galaxy assembly. In this paper, we use a novel approach of applying finite-resolution deconvolution on ground-based images of the COSMOS field to resolve ...

IOP Publishing Ltd2022

From starburst to quenching: merger-driven evolution of the star formation regimes in a shell galaxy

Jonathan Erik Peter Petersson

Shell galaxies make a class of tidally distorted galaxies, characterized by wide concentric arc(s), extending out to large galactocentric distances with sharp outer edges. Recent observations of young massive star clusters in the prominent outer shell of N ...

OXFORD UNIV PRESS2022

A stellar stream remnant of a globular cluster below the metallicity floor

Pascale Jablonka, Carmela Lardo

Stellar ejecta gradually enrich the gas out of which subsequent stars form, making the least chemically enriched stellar systems direct fossils of structures formed in the early Universe(1). Although a few hundred stars with metal content below 1,000th of ...

NATURE PORTFOLIO2022

Stellar metallicity gradients of Local Group dwarf galaxies

Pascale Jablonka, Yves Revaz

Aims. We explore correlations between the strength of metallicity gradients in Local Group dwarf galaxies and their stellar mass, star formation history timescales, and environment. Methods. We performed a homogeneous analysis of literature spectroscopic d ...

2022

Energy Bounds For A Fourth-Order Equation In Low Dimensions Related To Wave Maps

Tobias Johannes Schmid

For compact, isometrically embedded Riemannian manifolds N -> R-L, we introduce a fourth-order version of the wave maps equation. By energy estimates, we prove an a priori estimate for smooth local solutions in the energy subcritical dimension n = 1, 2. Th ...

AMER MATHEMATICAL SOC2022

Origin of stellar prolate rotation in a cosmologically simulated faint dwarf galaxy

Pascale Jablonka, Yves Revaz

Stellar prolate rotation in dwarf galaxies is rather uncommon, with only two known galaxies in the Local Group showing such feature (Phoenix and And II). Cosmological simulations show that in massive early-type galaxies prolate rotation likely arises from ...

OXFORD UNIV PRESS2021

Molecular gas in distant brightest cluster galaxies

Gianluca Castignani

The mechanisms governing the stellar mass assembly and star formation history of brightest cluster galaxies (BCGs) are still being debated. By means of new and archival molecular gas observations we investigate the role of dense megaparsec-scale environmen ...

2020

Molecular clouds in the Cosmic Snake normal star-forming galaxy 8 billion years ago

Jean-Paul Richard Kneib, Daniel Pfenniger, Johan Richard

The cold molecular gas in contemporary galaxies is structured in discrete cloud complexes. These giant molecular clouds (GMCs), with 10(4)-10(7) solar masses (M-circle dot) and radii of 5-100 parsecs, are the seeds of star formation(1). Highlighting the mo ...

NATURE PUBLISHING GROUP2019

The impact of cored density profiles on the observable quantities of dwarf spheroidal galaxies

Yves Revaz, David Richard Harvey, Loïc Hausammann

We modify the chemo-dynamical code GEAR to simulate the impact of self-interacting dark matter (SIDM) on the observable quantities of 19 low-mass dwarf galaxies with a variety star-forming properties. We employ a relatively high, velocity independent cross ...

OXFORD UNIV PRESS2018

The Pristine survey - I. Mining the Galaxy for the most metal-poor stars

Pascale Jablonka, Nicolas Lawrence Etienne Longeard

We present the Pristine survey, a new narrow-band photometric survey focused on the metallicity-sensitive Ca H&K lines and conducted in the Northern hemisphere with the wide-field imager MegaCam on the Canada-France-Hawaii Telescope. This paper reviews our ...

Oxford Univ Press2017

Molecular gas properties of a lensed star-forming galaxy at z similar to 3.6: a case study

Jean-Paul Richard Kneib, Benjamin Yvan Alexandre Clement, Johan Richard

We report on the galaxy MACSJ0032-arc at z(CO) = 3.6314 discovered during the Herschel Lensing snapshot Survey of massive galaxy clusters, and strongly lensed by the cluster MACSJ0032.1+1808. The successful detections of its rest-frame ultraviolet (UV), op ...

Edp Sciences S A2017