Publications associées à What is the Milky Way outer halo made of? High resolution spectroscopy of distant red giants

Publications associées (47)

Euclid: A complete Einstein ring in NGC 6505

Frédéric Courbin, Georges Meylan, Benjamin Yvan Alexandre Clement, Javier Alejandro Acevedo Barroso

We report the discovery of a complete Einstein ring around the elliptical galaxy NGC 6505, at z = 0.042. This is the first strong gravitational lens discovered in Euclid and the first in an NGC object from any survey. The combination of the low redshift of ...

2025

The MBH-M∗ Relation up to z ∼ 2 through Decomposition of COSMOS-Web NIRCam Images

Michaela Hirschmann

Our knowledge of relations between supermassive black holes and their host galaxies at z greater than or similar to 1 is still limited, even though being actively sought out to z similar to 6. Here, we use the high resolution and sensitivity of JWST to mea ...

IOP Publishing Ltd2025

The importance of nuclear star clusters for massive black hole growth and nuclear star formation in simulated low-mass galaxies

Michaela Hirschmann, Jonathan Erik Peter Petersson

Observed low-mass galaxies with nuclear star clusters (NSCs) can host accreting massive black holes (MBH). We present simulations of dwarf galaxies (M-baryon similar to 0.6-2.4x10(8)M(circle dot)) at solar mass resolution (0.5M(circle dot)

OXFORD UNIV PRESS2025

Euclid preparation: LXVII. Deep learning true galaxy morphologies for weak lensing shear bias calibration

Frédéric Courbin, Georges Meylan

To date, galaxy image simulations for weak lensing surveys usually approximate the light profiles of all galaxies as a single or double Sérsic profile, neglecting the influence of galaxy substructures and morphologies deviating from such a simplified param ...

2025

Ambipolar diffusion and the mass-to-flux ratio in a turbulent collapsing cloud

Aris Evangelos Tritsis

Context. The formation of stars is governed by the intricate interplay of nonideal magnetohydrodynamic (MHD) effects, gravity, and turbulence. Computational challenges have hindered a comprehensive 3D exploration of this interplay, posing a longstanding ch ...

2025

CAPERS-LRD-z9: A Gas-enshrouded Little Red Dot Hosting a Broad-line Active Galactic Nucleus at z = 9.288

Michaela Hirschmann

We present CAPERS-LRD-z9, a little red dot (LRD) that we confirm to be a z = 9.288 broad-line active galactic nucleus (BLAGN). First identified as a high-redshift LRD candidate from PRIMER NIRCam photometry, follow-up NIRSpec/PRISM spectroscopy of CAPERS-L ...

2025

SPINN: Advancing Cosmological Simulations of Fuzzy Dark Matter with Physics Informed Neural Networks

Emma Elizabeth Tolley, Ashutosh Kumar Mishra

Physics-informed neural networks (PINNs) have emerged as a powerful tool for solving differential equations by integrating physical laws into the learning process. This work leverages PINNs to simulate gravitational collapse, a critical phenomenon in astro ...

2025

Virgo Filaments. IV. Using WISE to Measure the Modification of Star-forming Disks in the Extended Regions Around the Virgo Cluster

Pascale Jablonka, Yannick Michael Bahé

Recent theoretical work and targeted observational studies suggest that filaments are sites of galaxy preprocessing. The aim of the WISESize project is to directly probe galaxies over the full range of environments to quantify and characterize extrinsic ga ...

IOP Publishing Ltd2025

Heavy neutron stars from light scalars

Stefan Stelzl

We study how light scalar fields can change the stellar landscape by triggering a new phase of nuclear matter. Scalars coupled to nucleons can develop a non-trivial expectation value at finite baryon density. This sourcing of a scalar reduces the nucleon m ...

Springer2025

Optimal reconstruction of baryon acoustic oscillations for DESI 2024

Jiaxi Yu

Baryon acoustic oscillations (BAO) provide a robust standard ruler to measure the expansion history of the Universe through galaxy clustering. Density-field reconstruction is now a widely adopted procedure for increasing the precision and accuracy of the B ...

2025

Search for gamma-ray spectral lines from dark-matter annihilation with the DAMPE satellite

Jennifer Maria Frieden

The annihilation of dark-matter particles may lead to the production of monochromatic gamma-ray emission. In this contribution, the search for spectral lines in the gamma-ray spectrum, using eight years of data collected with the space-borne Dark Matter Pa ...

EDP Sciences2025

Radio halo detection in MWA data using deep neural networks and generative data augmentation

Jean-Paul Richard Kneib, Emma Elizabeth Tolley, Shreyam Parth Krishna, Ashutosh Kumar Mishra

Detecting diffuse radio emission, such as from haloes, in galaxy clusters is crucial for understanding large-scale structure formation in the universe. Traditional methods, which rely on X-ray and Sunyaev-Zeldovich (SZ) cluster pre-selection, introduce bia ...

OXFORD UNIV PRESS2025

COSMOS-Web: Intrinsically Luminous z ≳ 10 Galaxy Candidates Test Early Stellar Mass Assembly

Michaela Hirschmann

We report the discovery of 15 exceptionally luminous 10 less than or similar to z less than or similar to 14 candidate galaxies discovered in the first 0.28 deg(2) of JWST/NIRCam imaging from the COSMOS-Web survey. These sources span rest-frame UV magnitud ...

Iop Publishing Ltd2024

The Origins of Gas Accreted by Supermassive Black Holes: The Importance of Recycled Gas

Michaela Hirschmann

We investigate the fueling mechanisms of supermassive black holes (SMBHs) by analyzing 10 zoom-in cosmological simulations of massive galaxies, with stellar masses 1011-12 M circle dot and SMBH masses 108.9-9.7 M circle dot at z = 0, featuring various majo ...

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

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

On the origin of globular clusters in a hierarchical universe

Michaela Hirschmann

We present an end-to-end description of the formation of globular clusters (GCs) combining a treatment for their formation and dynamical evolution within galaxy haloes with a state-of-the-art semi-analytic simulation of galaxy formation. Our approach allow ...

2024

Evolution of the Size-Mass Relation of Star-forming Galaxies Since z=5.5 Revealed by CEERS

Michaela Hirschmann

We combine deep imaging data from the CEERS early release JWST survey and Hubble Space Telescope imaging from CANDELS to examine the size-mass relation of star-forming galaxies and the morphology-quenching relation at stellar masses M-star >= 10(9.5)M(circ ...

Iop Publishing Ltd2024

Discovery of a Rare Group of Dwarf Galaxies in the Local Universe

Oliver Müller

We report the discovery of a rare isolated group of five dwarf galaxies located at z = 0.0086 (D = 36 Mpc). All member galaxies are star forming, blue, and gas rich, with g − r indices ranging from 0.2 to 0.6 mag, and two of them show signs of ongoing mutu ...

2024

Euclid: Validation of the MontePython forecasting tools

Maurizio Martinelli, Frédéric Courbin, Georges Meylan, Julien Lesgourgues, Slobodan Ilic

Context. The Euclid mission of the European Space Agency will perform a survey of weak lensing cosmic shear and galaxy clustering in order to constrain cosmological models and fundamental physics. Aims. We expand and adjust the mock Euclid likelihoods of t ...

Edp Sciences S A2024

Extremely Red Galaxies at z=5-9 with MIRI and NIRSpec: Dusty Galaxies or Obscured Active Galactic Nuclei?

Michaela Hirschmann

We study a new population of extremely red objects (EROs) recently discovered by the James Webb Space Telescope (JWST) based on their NIRCam colors F277W - F444W > 1.5 mag. We find 37 EROs in the Cosmic Evolution Early Release Science Survey (CEERS) field ...

Iop Publishing Ltd2024