Mediaspace scheduled maintenance: Aug 25, 2026 07:00 - 12:00 AM. During this time, videos will be temporarily unavailable. Check status updates.

Concept

Dispersion des vitesses

Publications associées (31)

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

Hidden Little Monsters: Spectroscopic Identification of Low-mass, Broad-line AGNs at z> 5 with CEERS

Michaela Hirschmann

We report on the discovery of two low-luminosity, broad-line active galactic nuclei (AGNs) at z > 5 identified using JWST NIRSpec spectroscopy from the Cosmic Evolution Early Release Science (CEERS) survey. We detect broad Ha emission in the spectra of bot ...

Iop Publishing Ltd2023

Strong gravitational lensing by AGNs as a probe of the quasar-host relations in the distant Universe

Frédéric Courbin, Malte Tewes, Martin Raoul Robert Millon, Aymeric Alexandre Galan

A rare case of a quasar acting as a gravitational lens allows a precise determination of the mass of the quasar's host galaxy and offers a new path to studying the connections between supermassive black holes and their host galaxies. ...

NATURE PORTFOLIO2023

The connection between mergers and AGN activity in simulated and observed massive galaxies

Michaela Hirschmann

We analyse a suite of 29 high-resolution zoom-in cosmological hydrodynamic simulations of massive galaxies with stellar masses M-star > 10(10.9) M-circle dot, with the goal of better understanding merger activity among active galactic nuclei (AGN), AGN act ...

Oxford Univ Press2023

The Pristine dwarf galaxy survey - IV. Probing the outskirts of the dwarf galaxy Bootes I

Pascale Jablonka, Nicolas Lawrence Etienne Longeard, Romain Ely Roland Lucchesi

We present a new spectroscopic study of the dwarf galaxy Bootes I (Boo I) with data from the Anglo-Australian Telescope and its AAOmega spectrograph together with the Two Degree Field multi-object system. We observed 36 high-probability Boo I stars selecte ...

OXFORD UNIV PRESS2022

Feasibility of Detecting Interstellar Panspermia in Astrophysical Environments

Claudio Grimaldi

The proposition that life can spread from one planetary system to another (interstellar panspermia) has a long history, but this hypothesis is difficult to test through observations. We develop a mathematical model that takes parameters such as the microbi ...

IOP PUBLISHING LTD2021

The Tucana dwarf spheroidal galaxy: not such a massive failure after all

Pascale Jablonka

Context. Isolated local group (LG) dwarf galaxies have evolved most or all of their life unaffected by interactions with the large LG spirals and therefore offer the opportunity to learn about the intrinsic characteristics of this class of objects. Aims. O ...

2020

The Pristine Inner Galaxy Survey (PIGS) I: tracing the kinematics of metal-poor stars in the Galactic bulge

Carmela Lardo, Nicolas Lawrence Etienne Longeard

Our Galaxy is known to contain a central boxy/peanut-shaped bulge, yet the importance of a classical, pressure-supported component within the central part of the Milky Way is still being debated. It should be most visible at low metallicity, a regime that ...

OXFORD UNIV PRESS2020

Kinematic and metallicity properties of the Aquarius dwarf galaxy from FORS2 MXU spectroscopy

Pascale Jablonka

Context. Dwarf galaxies found in isolation in the Local Group (LG) are unlikely to have interacted with the large LG spirals, and therefore environmental effects such as tidal and ram-pressure stripping should not be the main drivers of their evolution. Ai ...

EDP SCIENCES S A2020

The Hidden Past of M92: Detection and Characterization of a Newly Formed 17 degrees Long Stellar Stream Using the Canada-France Imaging Survey

Nicolas Lawrence Etienne Longeard

We present an analysis of the structure, kinematics, and orbit of a newly found stellar stream emanating from the globular cluster M92 (NGC 6341). This stream was discovered in an improved matched-filter map of the outer Galaxy, based on a "color-color-mag ...

IOP PUBLISHING LTD2020

The Pristine Dwarf-Galaxy survey - II. In-depth observational study of the faint Milky Way satellite Sagittarius II

Pascale Jablonka, Nicolas Lawrence Etienne Longeard

We present an extensive study of the Sagittarius II (Sgr II) stellar system using MegaCam g and i photometry, narrow-band, metallicity-sensitive calcium H&K doublet photometry and Keck II/DEIMOS multiobject spectroscopy. We derive and refine the Sgr II str ...

OXFORD UNIV PRESS2020

H0LiCOW XII. Lens mass model of WFI2033-4723 and blind measurement of its time-delay distance and H-0

Frédéric Courbin, Hung-Hsu Chan, Vivien François Bonvin

We present the lens mass model of the quadruply-imaged gravitationally lensed quasar WFI2033 - 4723, and perform a blind cosmographical analysis based on this system. Our analysis combines (1) time-delay measurements from 14 yr of data obtained by the COSm ...

OXFORD UNIV PRESS2020

Preprocessing among the Infalling Galaxy Population of EDisCS Clusters

Pascale Jablonka

We present results from a low-resolution spectroscopic survey for 21 galaxy clusters at 0.4 < z < 0.8 selected from the ESO Distant Cluster Survey. We measured spectra using the low-dispersion prism in IMACS on the Magellan Baade telescope and calculate re ...

IOP PUBLISHING LTD2019

Tidal Interactions and Mergers in Intermediate-redshift EDisCS Clusters

Pascale Jablonka

We study the fraction of tidal interactions and mergers (TIMs) with well-identified observability timescales (f(TIM)) in group, cluster, and accompanying field galaxies and its dependence on redshift (z), cluster velocity dispersion (sigma), and environmen ...

IOP PUBLISHING LTD2018

Pristine dwarf galaxy survey - I. A detailed photometric and spectroscopic study of the very metal-poor Draco II satellite

Pascale Jablonka, Nicolas Lawrence Etienne Longeard, Silvia Martin de Nicolas Agut

We present a detailed study of the faint Milky Way satellite Draco II (Dra II) from deep CFHT/MegaCam broad-band g and i photometry and narrow-band metallicity-sensitive CaliK observations, along with follow-up Keck II/DEIMOS multi-object spectroscopy. For ...

OXFORD UNIV PRESS2018

Photonic chip-based soliton frequency combs covering the biological imaging window

Tobias Kippenberg, Junqiu Liu, Maxim Karpov, Martin Hubert Peter Pfeiffer, Anton Lukashchuk

Dissipative Kerr solitons (DKS) in optical microresonators provide a highly miniaturised, chip-integrated frequency comb source with unprecedentedly high repetition rates and spectral bandwidth. To date, such frequency comb sources have been successfully a ...

Nature Publishing Group2018

From model to radar variables: a new forward polarimetric radar operator for COSMO

Alexis Berne, Daniel Wolfensberger

In this work, a new forward polarimetric radar operator for the COSMO numerical weather prediction (NWP) model is proposed. This operator is able to simulate measurements of radar reflectivity at horizontal polarization, differential reflectivity as well a ...

Copernicus GmbH2018

Survey of Gravitationally Lensed Objects in HSC Imaging (SuGOHI). II. Environments and Line-of-Sight Structure of Strong Gravitational Lens Galaxies to z similar to 0.8

Hung-Hsu Chan

We investigate the local and line-of-sight (LOS) overdensities of strong gravitational lens galaxies using wide-area multiband imaging from the Hyper Suprime-Cam Subaru Strategic Program. We present 41. new definite or probable lens candidates discovered i ...

2018

Gaia Data Release 1 Open cluster astrometry: performance, limitations, and future prospects

Stephan Morgenthaler, Shuangqing Liao

Context. The first Gaia Data Release contains the Tycho-Gaia Astrometric Solution (TGAS). This is a subset of about 2 million stars for which, besides the position and photometry, the proper motion and parallax are calculated using Hipparcos and Tycho-2 po ...

Edp Sciences S A2017

HOLiCOW - IV. Lens mass model of HE 0435-1223 and blind measurement of its time-delay distance for cosmology

Frédéric Courbin, Vivien François Bonvin

Strong gravitational lenses with measured time delays between the multiple images allow a direct measurement of the time-delay distance to the lens, and thus a measure of cosmological parameters, particularly the Hubble constant, H-0. We present a blind le ...

Oxford Univ Press2017