Publications associées à Sursauteur X

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

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

A Microlensing Accretion Disk Size Measurement in the Lensed Quasar WFI 2026-4536

Frédéric Courbin, Vivien François Bonvin, Martin Raoul Robert Millon

We use 13 seasons of R-band photometry from the 1.2 m Leonard Euler Swiss Telescope at La Silla to examine microlensing variability in the quadruply imaged lensed quasar WFI 2026-4536. The lightcurves exhibit similar to 0.2 mag of uncorrelated variability ...

IOP PUBLISHING LTD2020

High intensity x-ray interaction with a model bio-molecule system: double-core-hole states and fragmentation of formamide

Christoph Bostedt, Yiming Li

Formamide, a simple model bio-molecule (HCONH2), is irradiated with high intensity, ultrashort pulses from an x-ray free electron laser. Ionic fragments resulting from photoionization and subsequent decay processes are recorded, as well as the electronic s ...

IOP Publishing2020

Probing Molecular Chirality by Orbital-Angular-Momentum-Carrying X-ray Pulses

Jérémy Raymond Jean Maurice Rouxel

A twisted X-ray beam with orbital angular momentum is employed in a theoretical study to probe molecular chirality. A nonlocal response description of the matter-field coupling is adopted to account for the field short wavelength and the structured spatial ...

AMER CHEMICAL SOC2019

Probing alloy formation using different excitonic species: The particular case of InGaN

Nicolas Grandjean, Raphaël Butté, Gordon Jens Callsen

Since the 1960s, alloys are grouped into two classes, featuring bound states in the bandgap (I - GaP:N, ZnTe:O, etc.) or additional, non-discrete, band states (II - SiGe, GaAsP, InGaAs, etc.). Therefore, one can observe either a rich and informative zoo of ...

IEEE2019

Constant light element abundances suggest that the extended P1 in NGC 2808 is not a consequence of CNO-cycle nucleosynthesis

Carmela Lardo

Recent photometric results have identified a new population among globular cluster stars. This population, referred to as the 'extended P1', has been suggested to be the manifestation of a new abundance pattern where the initial mass fraction of He changes ...

OXFORD UNIV PRESS2019

Tracing the formation of the Milky Way through ultra metal-poor stars

Pascale Jablonka, Nicolas Lawrence Etienne Longeard

We use Gaia DR2 astrometric and photometric data, published radial velocities and MESA models to infer distances, orbits, surface gravities, and effective temperatures for all ultra metal-poor stars ([Fe/H] < -4.0 dex) available in the literature. Assuming ...

OXFORD UNIV PRESS2019

Growing a 'cosmic beast': observations and simulations of MACS J0717.5+3745

Jean-Paul Richard Kneib, David Richard Harvey, Barney Frederick Drake, Mathilde Jauzac, Matthieu Schaller, Matthew Aaron Robertson, Elena Cristina Dalla Vecchia, Richard Massey

We present a gravitational lensing and X-ray analysis of a massive galaxy cluster and its surroundings. The core of MACS J0717.5+3745 (M(R < 1Mpc) similar to 2 x 10(15) M-circle dot, z = 0.54) is already known to contain four merging components. We show th ...

OXFORD UNIV PRESS2018

The Gaia-ESO Survey: properties of newly discovered Li-rich giants

Carmela Lardo, Joao André Gomes de Sá e Sousa, Fadi Atef Bayoud

Aims. We report 20 new lithium-rich giants discovered within the Gaia-ESO Survey, including the first Li-rich giant with an evolutionary stage confirmed by CoRoT (Convection, Rotation and planetary Transits) data. We present a detailed overview of the prop ...

EDP SCIENCES S A2018

Experiment and Machine Protection from Fast Losses caused by Crab Cavities in the High Luminosity LHC

Andrea Santamaría García

The High Luminosity Large Hadron Collider (HL-LHC) upgrade aims for a tenfold increase in integrated luminosity compared to the nominal Large Hadron Collider (LHC), and for operation at a leveled luminosity five times higher than the nominal LHC peak lumin ...

EPFL2018

MULTIWAVELENGTH STUDY OF QUIESCENT STATES OF Mrk 421 WITH UNPRECEDENTED HARD X-RAY COVERAGE PROVIDED BY NuSTAR IN 2013

Xin Chen, Thomas Günther Bretz

We present coordinated multiwavelength observations of the bright, nearby BL Lacertae object Mrk 421 taken in 2013 January-March, involving GASP-WEBT, Swift, NuSTAR, Fermi-LAT, MAGIC, VERITAS, and other collaborations and instruments, providing data from r ...

Iop Publishing Ltd2016

Searching for decaying dark matter in deep XMM-Newton observation of the Draco dwarf spheroidal

Alexey Boyarsky, Oleg Ruchayskiy, Andrii Neronov

We present results of a search for the 3.5 keV emission line in our recent very long (similar to 1.4 Ms) XMM-Newton observation of the Draco dwarf spheroidal galaxy. The astrophysical X-ray emission from such dark matter-dominated galaxies is faint, thus t ...

Wiley-Blackwell2016

Instrument intercomparison in the pulsed neutron fieldsat the CERN HiRadMat facility

Nikolaos Charitonidis, Daniel Perrin

An intercomparison of the performances of active neutron detectors was carried out in pulsed neutron fields in the new HiRadMat facility at CERN. Five detectors were employed: four of them (two ionization chambers and two rem counters) are routinely employ ...

Pergamon-Elsevier Science Ltd2014

Searching for soft relativistic jets in core-collapse supernovae with the IceCube optical follow-up program

Shirit Cohen, Mathieu Ribordy, Matthias Wolf, Xiaoxia Bai

Context. Transient neutrino sources such as gamma-ray bursts (GRBs) and supernovae (SNe) are hypothesized to emit bursts of high-energy neutrinos on a time-scale of less than or similar to 100 s. While GRB neutrinos would be produced in high relativistic j ...

2012

Further Evidence That Quasar X-Ray Emitting Regions Are Compact: X-Ray And Optical Microlensing In The Lensed Quasar Q J0158-4325

Frédéric Courbin, Georges Meylan, Malte Tewes

We present four new seasons of optical monitoring data and six epochs of X-ray photometry for the doubly imaged lensed quasar Q J0158-4325. The high-amplitude, short-period microlensing variability for which this system is known has historically precluded ...

Iop Publishing Ltd2012

SEARCH FOR MUON NEUTRINOS FROM GAMMA-RAY BURSTS WITH THE IceCube NEUTRINO TELESCOPE

Shirit Cohen, Mathieu Ribordy, Levent Demirörs, Xiaoxia Bai

We present the results of searches for high-energy muon neutrinos from 41 gamma-ray bursts (GRBs) in the northern sky with the IceCube detector in its 22 string configuration active in 2007/2008. The searches cover both the prompt and a possible precursor ...

2010

The dynamical and chemical evolution of dwarf spheroidal galaxies

Pascale Jablonka, Yves Revaz

We present a large sample of fully self-consistent hydrodynamical Nbody/Tree-SPH simulations of isolated dwarf spheroidal galaxies (dSphs). It has enabled us to identify the key physical parameters and mechanisms at the origin of the observed variety in th ...

2009

LESS THAN 10 PERCENT OF STAR FORMATION IN z similar to 0.6 MASSIVE GALAXIES IS TRIGGERED BY MAJOR INTERACTIONS

Both observations and simulations show that major tidal interactions or mergers between gas-rich galaxies can lead to intense bursts of star formation. Yet, the average enhancement in star formation rate (SFR) in major mergers and the contribution of such ...

2009