29 results match your criteria: "Centre de Recherche Astrophysique de Lyon[Affiliation]"

Monoclonal antibody (mAbs) therapeutics cannot evade the occurrence of adverse effects. Thus, mAbs are commonly triggering immune responses corresponding to the expression of antidrug antibodies. Antidrug antibodies can neutralize mAbs, leading to their inhibition and hasten clearance, which dramatically hampers their therapeutic effects.

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The canonical theory for planet formation in circumstellar disks proposes that planets are grown from initially much smaller seeds. The long-considered alternative theory proposes that giant protoplanets can be formed directly from collapsing fragments of vast spiral arms induced by gravitational instability-if the disk is gravitationally unstable. For this to be possible, the disk must be massive compared with the central star: a disk-to-star mass ratio of 1:10 is widely held as the rough threshold for triggering gravitational instability, inciting substantial non-Keplerian dynamics and generating prominent spiral arms.

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Background: Elastic deformations of gravitating cylindrical bodies are relevant for state-of-the-art photonic experiments, as they affect the physical properties of materials under consideration, impacting wave propagation. This is of key importance for a recently planned experiment to explore the influence of the gravitational field on entangled photons propagating in waveguides. The purpose of this work is to determine these elastic deformations as functions of temperature, pressure, and of the gravitational field.

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Tight relationships exist in the local Universe between the central stellar properties of galaxies and the mass of their supermassive black hole (SMBH). These suggest that galaxies and black holes co-evolve, with the main regulation mechanism being energetic feedback from accretion onto the black hole during its quasar phase. A crucial question is how the relationship between black holes and galaxies evolves with time; a key epoch to examine this relationship is at the peaks of star formation and black hole growth 8-12 billion years ago (redshifts 1-3).

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Galactic outflows are believed to play a critical role in the evolution of galaxies by regulating their mass build-up and star formation. Theoretical models assume bipolar shapes for the outflows that extend well into the circumgalactic medium (CGM), up to tens of kiloparsecs (kpc) perpendicular to the galaxies. They have been directly observed in the local Universe in several individual galaxies, for example, around the Milky Way and M82 (refs.

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Detecting gravitationally lensed supernovae is among the biggest challenges in astronomy. It involves a combination of two very rare phenomena: catching the transient signal of a stellar explosion in a distant galaxy and observing it through a nearly perfectly aligned foreground galaxy that deflects light towards the observer. Here we describe how high-cadence optical observations with the Zwicky Transient Facility, with its unparalleled large field of view, led to the detection of a multiply imaged type Ia supernova, SN Zwicky, also known as SN 2022qmx.

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In multispectral digital in-line holographic microscopy (DIHM), aberrations of the optical system affect the repeatability of the reconstruction of transmittance, phase and morphology of the objects of interest. Here we address this issue first by model fitting calibration using transparent beads inserted in the sample. This step estimates the aberrations of the optical system as a function of the lateral position in the field of view and at each wavelength.

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Article Synopsis
  • The early Universe's galaxy growth is fueled by accretion of gas from surrounding areas.
  • A 100 kiloparsec-long filamentary stream of gas was discovered linking to the massive radio galaxy 4C 41.17.
  • This gas stream has been identified as a key source for star formation, highlighting that materials for new stars can exist in cosmic streams outside galaxies.
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Star formation in half of massive galaxies was quenched by the time the Universe was 3 billion years old. Very low amounts of molecular gas seem to be responsible for this, at least in some cases, although morphological gas stabilization, shock heating or activity associated with accretion onto a central supermassive black hole are invoked in other cases. Recent studies of quenching by gas depletion have been based on upper limits that are insufficiently sensitive to determine this robustly, or stacked emission with its problems of averaging.

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Anti-clustering in the national SARS-CoV-2 daily infection counts.

PeerJ

August 2021

Institute of Astronomy, Faculty of Physics, Astronomy and Informatics, ul. Grudziadzka 5, Nicolaus Copernicus University of Torun, Torun, Poland.

The noise in daily infection counts of an epidemic should be super-Poissonian due to intrinsic epidemiological and administrative clustering. Here, we use this clustering to classify the official national SARS-CoV-2 daily infection counts and check for infection counts that are unusually anti-clustered. We adopt a one-parameter model of infections per cluster, dividing any daily count into 'clusters', for 'country' .

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ALMA observations of the young protostellar system Barnard 1b: signatures of an incipient hot corino in B1b-S.

Astron Astrophys

December 2018

Sorbonne Université, Observatoire de Paris, Université PSL, École normale supérieure, CNRS, LERMA, F-75014, Paris, France.

The Barnard 1b core shows signatures of being at the earliest stages of low-mass star formation, with two extremely young and deeply embedded protostellar objects. Hence, this core is an ideal target to study the structure and chemistry of the first objects formed in the collapse of prestellar cores. We present ALMA Band 6 spectral line observations at ~0.

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The multiple merger assembly of a hyperluminous obscured quasar at redshift 4.6.

Science

November 2018

Université Lyon, Université Lyon1, École Normale Supérieure de Lyon, Centre National de la Recherche Scientifique, Centre de Recherche Astrophysique de Lyon UMR5574, 69230 Saint-Genis-Laval, France.

Galaxy mergers and gas accretion from the cosmic web drove the growth of galaxies and their central black holes at early epochs. We report spectroscopic imaging of a multiple merger event in the most luminous known galaxy, WISE J224607.56-052634.

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Change history: In this Letter, author M. Akhlaghi should be associated with affiliation (2) rather than (3). This error has been corrected online.

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Nearly all the sky is covered by Lyman-α emission around high-redshift galaxies.

Nature

October 2018

Leibniz-Institut für Astrophysik Potsdam (AIP), Potsdam, Germany.

Galaxies are surrounded by large reservoirs of gas, mostly hydrogen, that are fed by inflows from the intergalactic medium and by outflows from galactic winds. Absorption-line measurements along the lines of sight to bright and rare background quasars indicate that this circumgalactic medium extends far beyond the starlight seen in galaxies, but very little is known about its spatial distribution. The Lyman-α transition of atomic hydrogen at a wavelength of 121.

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Compact in-line lensfree digital holographic microscope.

Methods

March 2018

Laboratory of Applied Photonics Devices, École Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland.

Phase imaging provides intensity contrast to visualize transparent samples such as found in biology without any staining. Among them, digital holographic microscopy (DHM) is a well-known quantitative phase method. Lensfree implementations of DHMs offer the added advantage to provide large field of views (several mm compared to several hundred μm) and more compact setups that traditional DHM which have high quality microscope objectives.

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Evidence for disks at an early stage in class 0 protostars?

Astron Astrophys

October 2017

LERMA, Observatoire de Paris, PSL Research University, CNRS, Sorbonne Universités, UPMC Univ. Paris 06, Ecole Normale Supérieure, F-92190 Meudon, France.

Aims: The formation epoch of protostellar disks is debated because of the competing roles of rotation, turbulence, and magnetic fields in the early stages of low-mass star formation. Magnetohydrodynamics simulations of collapsing cores predict that rotationally supported disks may form in strongly magnetized cores through ambipolar diffusion or misalignment between the rotation axis and the magnetic field orientation. Detailed studies of individual sources are needed to cross check the theoretical predictions.

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A massive, dead disk galaxy in the early Universe.

Nature

June 2017

Dark Cosmology Centre, Niels Bohr Institute, University of Copenhagen, Juliane Maries Vej 32, København Ø, 2100, Denmark.

At redshift z = 2, when the Universe was just three billion years old, half of the most massive galaxies were extremely compact and had already exhausted their fuel for star formation. It is believed that they were formed in intense nuclear starbursts and that they ultimately grew into the most massive local elliptical galaxies seen today, through mergers with minor companions, but validating this picture requires higher-resolution observations of their centres than is currently possible. Magnification from gravitational lensing offers an opportunity to resolve the inner regions of galaxies.

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One of the simplest viable models for dark matter is an additional neutral scalar, stabilised by a symmetry. Using the GAMBIT package and combining results from four independent samplers, we present Bayesian and frequentist global fits of this model. We vary the singlet mass and coupling along with 13 nuisance parameters, including nuclear uncertainties relevant for direct detection, the local dark matter density, and selected quark masses and couplings.

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Galaxies grow through both internal and external processes. In about 10% of nearby red galaxies with little star formation, gas and stars are counter-rotating, demonstrating the importance of external gas acquisition in these galaxies. However, systematic studies of such phenomena in blue, star-forming galaxies are rare, leaving uncertain the role of external gas acquisition in driving evolution of blue galaxies.

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A large light-mass component of cosmic rays at 10(17)-10(17.5) electronvolts from radio observations.

Nature

March 2016

Max-Planck-Institut für Radioastronomie, Auf dem Hügel 69, 53121 Bonn, Germany.

Cosmic rays are the highest-energy particles found in nature. Measurements of the mass composition of cosmic rays with energies of 10(17)-10(18) electronvolts are essential to understanding whether they have galactic or extragalactic sources. It has also been proposed that the astrophysical neutrino signal comes from accelerators capable of producing cosmic rays of these energies.

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Fast-moving features in the debris disk around AU Microscopii.

Nature

October 2015

Department of Physics and Astronomy, University of Oklahoma, 440 West Brooks Street, Norman, Oklahoma 73019, USA.

In the 1980s, excess infrared emission was discovered around main-sequence stars; subsequent direct-imaging observations revealed orbiting disks of cold dust to be the source. These 'debris disks' were thought to be by-products of planet formation because they often exhibited morphological and brightness asymmetries that may result from gravitational perturbation by planets. This was proved to be true for the β Pictoris system, in which the known planet generates an observable warp in the disk.

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Physics at the [Formula: see text] linear collider.

Eur Phys J C Part Fields

August 2015

Department of Physics, Tohoku University, Sendai, Miyagi Japan.

Article Synopsis
  • The report provides an in-depth review of physics research at a linear collider operating between specific energy levels of 100 GeV to 3 TeV, considering recent results from the LHC and other low-energy and astroparticle experiments.
  • It emphasizes key areas of study, including the Higgs boson, top quark, and electroweak precision physics, while also exploring theories beyond the standard model, like supersymmetry and extra gauge bosons.
  • Additionally, the report examines the implications of this research in the context of cosmology, highlighting the broader significance of these findings.
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We present measurements of radio emission from cosmic ray air showers that took place during thunderstorms. The intensity and polarization patterns of these air showers are radically different from those measured during fair-weather conditions. With the use of a simple two-layer model for the atmospheric electric field, these patterns can be well reproduced by state-of-the-art simulation codes.

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Exploring CP violation in the MSSM.

Eur Phys J C Part Fields

February 2015

Université de Lyon, Université Lyon 1, Centre de Recherche Astrophysique de Lyon, CNRS, UMR 5574, 69561 Saint-Genis Laval Cedex, France ; Ecole Normale Supérieure de Lyon, Lyon, France ; Theory Division, CERN, 1211 Geneva 23, Switzerland ; Institut Universitaire de France, 103 boulevard Saint-Michel, 75005 Paris, France.

We explore the prospects for observing CP violation in the minimal supersymmetric extension of the Standard Model (MSSM) with six CP-violating parameters, three gaugino mass phases and three phases in trilinear soft supersymmetry-breaking parameters, using the CPsuperH code combined with a geometric approach to maximise CP-violating observables subject to the experimental upper bounds on electric dipole moments. We also implement CP-conserving constraints from Higgs physics, flavour physics and the upper limits on the cosmological dark matter density and spin-independent scattering. We study possible values of observables within the constrained MSSM (CMSSM), the non-universal Higgs model (NUHM), the CPX scenario and a variant of the phenomenological MSSM (pMSSM).

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A dusty, normal galaxy in the epoch of reionization.

Nature

March 2015

The Scottish Universities Physics Alliance, Institute for Astronomy, University of Edinburgh, Royal Observatory, Edinburgh, EH9 3HJ, UK.

Article Synopsis
  • Many early Universe galaxies forming stars at redshifts greater than 7 have been identified through deep ultraviolet imaging, but studying their properties via ultraviolet light is challenging.
  • A1689-zD1, a galaxy at redshift z = 7.5, represents this population and has been observed to have significant dust and stellar emissions.
  • This galaxy showcases that even at high redshifts, evolved galaxies with a dust-to-gas ratio similar to the Milky Way exist among the fainter star-forming galaxies in the early Universe.
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