A5008695353- Astrophysics and Star Formation Studies
- Stellar, planetary, and galactic studies
- Astro and Planetary Science
- Gamma-ray bursts and supernovae
- Astronomy and Astrophysical Research
- Astrophysical Phenomena and Observations
- Molecular Spectroscopy and Structure
- Atmospheric Ozone and Climate
- Galaxies: Formation, Evolution, Phenomena
- Metal Forming Simulation Techniques
- Astronomical Observations and Instrumentation
- Astrophysics and Cosmic Phenomena
- Metallurgy and Material Forming
- Pulsars and Gravitational Waves Research
- Aeolian processes and effects
- Planetary Science and Exploration
- Space Exploration and Technology
- SAS software applications and methods
- Laser and Thermal Forming Techniques
- Atomic and Subatomic Physics Research
- Geomagnetism and Paleomagnetism Studies
- Atmospheric aerosols and clouds
- Geophysics and Gravity Measurements
- Advanced Optical Sensing Technologies
- Material Science and Thermodynamics
Institut de Radioastronomie Millimétrique
2014-2024
Université Grenoble Alpes
2012-2023
University of Iowa
2023
Ausonius Institut de Recherche sur l'Antiquité et le Moyen age
2003-2022
Technische Universität Berlin
1991-2008
Max Planck Institute for Radio Astronomy
2001-2003
Observatoire de Paris
2000-2003
Laboratoire d’Etudes du Rayonnement et de la Matière en Astrophysique et Atmosphères
2003
Umicore (Belgium)
1999-2003
Max Planck Society
2000-2002
Variable X-ray and gamma-ray emission is characteristic of the most extreme physical processes in Universe, studying sources these energetic photons has been a major driver astronomy for past 50 years. Here we present multiwavelength observations unique selected transient, discovered by Swift, which was accompanied bright across electromagnetic spectrum, whose properties are unlike any previously observed source. We pinpoint event to center small, star-forming galaxy at redshift z=0.3534....
We present multiwavelength observations of the afterglow GRB 130427A, brightest (in total fluence) gamma-ray burst (GRB) past 29 yr. Optical spectroscopy from Gemini-North reveals redshift to be z = 0.340, indicating that its unprecedented brightness is primarily result relatively close proximity Earth; intrinsic luminosities both and are not extreme in comparison other bright GRBs. a large suite spanning 300 s 130 days after demonstrate shows simple, smooth evolution at all frequencies,...
Abstract We present a search for extragalactic fast blue optical transients (FBOTs) during Phase I of the Zwicky Transient Facility (ZTF). identify 38 candidates with durations above half-maximum light 1 day < t 1/2 12 days, which 28 have ( g − r ≲ −0.2 mag) colors at peak light. Of (28 FBOTs), 19 (13) can be spectroscopically classified as core-collapse supernovae (SNe): 11 (8) H- or He-rich (Type II/IIb/Ib) SNe, 6 (4) interacting IIn/Ibn) and 2 (1) H&He-poor Ic/Ic-BL) SNe. Two FBOTs...
We detect luminous emission from HCN, HCO+ and HNC 1--0 in the QSO ULIRG Mrk~231 with IRAM Plateau de Bure Interferometer at 1."55 by 1."28 resolution. All three lines show broad line wings - which are particularly prominent for HCN. Velocities found to be similar (750 km/s) those CO 1-0. This is first time bright has been detected a large-scale galactic outflow. find that both blue- red-shifted spatially extended least 0."75 (700 pc) north-south direction. The brighter (relative center...
We present IRAM/NOEMA and JVLA observations of the quasar J1342+0928 at z=7.54 report detections copious amounts dust [CII] emission in interstellar medium (ISM) its host galaxy. At this redshift, age universe is 690 Myr, about 10% younger than redshift previous record holder. Yet, ISM new galaxy significantly enriched by metals, as evidenced detection 158micron cooling line underlying far-infrared (FIR) continuum emission. To first order, FIR properties are similar to those found a slightly...
We obtained high resolution (0."25 to 0."90) observations of HCN and HCO+ J=3-2 the ultraluminous QSO galaxy Mrk231 with IRAM Plateau de Bure Interferometer. find luminous 3-2 emission in main disk we detect compact (r<90 pc) vibrationally excited 3-2, v2=1f centred on nucleus. The velocity field is strongly inclined (PA=155 deg.) compared east-west rotation disk. nuclear molecular mass estimated 8e8 Msun an average N(H2)of 1.2e24 cm-2. Prominent, spatially extended (>350 line wings...
Context. High-mass stars form in clusters, but neither the early fragmentation processes nor detailed physical leading to most massive are well understood. Aims. We aim understand fragmentation, as disk formation, outflow generation, and chemical during high-mass star formation on spatial scales of individual cores. Methods. Using IRAM Northern Extended Millimeter Array (NOEMA) combination with 30 m telescope, we have observed large program CORE 1.37 mm continuum spectral line emission at...
We derive an improved description of dust-driven stellar mass-loss for the cool winds carbon-rich tip-AGB stars. use pulsating wind models in which mass loss is driven by radiation pressure on dust grains, C-rich chemistry. From a larger set these models, selected representative dynamical (pulsational velocity amplitude , period P) and chemical (the abundance ratio) input parameters, approximative formula has been derived depends only parameters (effective temperature Teff, luminosity L M)....
We present a self–consistent time–dependent model for the oxygen–rich Mira variable IRC –20197. This includes consistent treatment of interactions among hydrodynamics, thermodynamics, radiative transfer, equilibrium chemistry, and heterogeneous dust formation with TiO2 nuclei. The is determined by stellar parameters, mass , luminosity temperature solar abundances elements. pulsation star simulated piston at inner boundary where velocity varies sinusoidally period an amplitude . Based on...
At low redshift, a handful of gamma-ray bursts (GRBs) have been discovered with peak luminosities ($L_{\rm iso} < 10^{48.5}~\rm{erg\,s}^{-1}$) substantially lower than the average more distant ones > 10^{49.5}~\rm{erg\,s}^{-1}$). The properties several low-luminosity (low-$L$) GRBs indicate that they can be due to shock break-out, as opposed emission from ultrarelativistic jets. Owing this, it is highly debated how both populations are connected, and whether there continuum between them....
We use sub-arcsecond resolution ($\sim$0.4$''$) observations with NOEMA at 1.37 mm to study the dust emission and molecular gas of 18 high-mass star-forming regions. combine derived physical chemical properties individual cores in these regions estimate their ages. The temperature structure are determined by fitting H2CO CH3CN line emission. density profiles inferred from continuum visibilities. column densities 11 different species lines XCLASS. Within observed regions, we identify 22...
We investigate the molecular gas content of z~6 quasar host galaxies using IRAM / Northern Extended Millimeter Array. target 3mm dust continuum, and line emission from CO(6-5), CO(7-6), [CI]2-1 in 10 infra-red-luminous quasars that have been previously studied their 1mm continuum [CII] emission. detect CO(7-6) at various degrees significance all targeted sources, thus doubling number such detections quasars. The to flux density ratios are consistent with a modified black body spectrum...
We present the first results of a CO(2–1), (1–0), and 86 GHz SiO maser survey AGB stars, selected by their weak near-infrared excess. Among 65 sources sample we find 10 objects with low CO outflow velocities, km s-1. Typically, these show (much) wider features. Additionally, get 5 composite line profiles, i.e. narrow feature is superimposed on broader one, where both components are centered at same stellar velocity. The gas mass-loss rates, velocities velocity structures suggested profiles...
We present COSAS (CO Survey of late AGB Stars), a project to map and analyze the 12CO J = 1−0 2−1 line emission in representative sample circumstellar envelopes around post-AGB stars. The survey was undertaken with aim investigating small- large-scale morphological kinematical properties molecular environment surrounding stars early phases. For this, combines high sensitivity spatial resolving power IRAM Plateau de Bure interferometer better capability 30 m telescope extended emission....
Context. Dust is efficiently produced by cool giant stars, but the condensation of inorganic dust poorly understood. Observations key aluminum bearing molecules around evolved stars has enabled us to investigate nucleation alumina (Al2O3) in gas.
The Cygnus-X complex is a massive (a few $10^6$,M_⊙ molecular gas mass), nearby (1.4,kpc) star-forming region with several OB associations. Of these, Cyg OB2 the largest, at least 169 stars. DR18 largest globule near association, making it perfect target for investigating influence of ultraviolet radiation on clouds. By analyzing emission from different species, we aim to study structures toward using high angular-resolution line observations. As part Cygnus Allscale Survey Chemistry and...
We investigate the mass loss of highly evolved, low- and intermediate stars stellar samples with subsolar metallicity. give a qualitative as well quantitative description which can be applied to LMC/SMC-type populations. For that purpose we apply same approach did for solar metallicity calculate hydrodynamical wind models including dust formation LMC SMC abundances under consideration an adapted model assumption. In particular, improved treatment radiative transfer problem in order...