A5063284991- Astrophysics and Star Formation Studies
- Stellar, planetary, and galactic studies
- Astro and Planetary Science
- Molecular Spectroscopy and Structure
- Atmospheric Ozone and Climate
- Spectroscopy and Laser Applications
- Astronomy and Astrophysical Research
- Astronomical Observations and Instrumentation
- Galaxies: Formation, Evolution, Phenomena
- Advanced Chemical Physics Studies
- Astrophysical Phenomena and Observations
- Space Exploration and Technology
- Atomic and Molecular Physics
- Spacecraft and Cryogenic Technologies
- Geophysics and Gravity Measurements
- Gamma-ray bursts and supernovae
- Planetary Science and Exploration
- History and Developments in Astronomy
- SAS software applications and methods
- Laser-induced spectroscopy and plasma
- Astrophysics and Cosmic Phenomena
- Electron and X-Ray Spectroscopy Techniques
- nanoparticles nucleation surface interactions
- Fullerene Chemistry and Applications
- Superconducting and THz Device Technology
Institut d'Astrophysique Spatiale
2015-2024
Université Paris-Saclay
2000-2024
Centre National de la Recherche Scientifique
2014-2024
Université Paris-Sud
2010-2021
Université Paris Cité
2002-2006
Arcetri Astrophysical Observatory
1997-2006
Commissariat à l'Énergie Atomique et aux Énergies Alternatives
2006
CEA Paris-Saclay
2006
Université Joseph Fourier
2006
University of Groningen
2006
Molecular hydrogen is the most abundant molecule in universe. It first one to form and survive photo-dissociation tenuous environments. Its formation involves catalytic reactions on surface of interstellar grains. The micro-physics process has been investigated intensively last 20 years, parallel new astrophysical observational modeling progresses. In perspectives probable revolution brought by future satellite JWST, this article written present what we think know about H2 a variety
Context . JWST has taken the sharpest and most sensitive infrared (IR) spectral imaging observations ever of Orion Bar photodis-sociation region (PDR), which is part nearest massive star-forming Nebula, often considered to be ‘prototypical’ strongly illuminated PDR. Aims We investigate impact radiative feedback from stars on their natal cloud focus transition H II atomic PDR – crossing ionisation front (IF) –, subsequent molecular dissociation (DF). Given prevalence PDRs in interstellar...
Accretion rates from disks around pre-main sequence stars are of importance for our understanding planetary formation and disk evolution. We provide in this paper estimates the mass accretion a large sample Herbig Ae stars. obtained medium resolution 2 micron spectra used results to compute values Macc measured luminosity Br_gamma emission line, using well established correlation between L(Br_gamma) Lacc. find that 80% stars, all which have evidence an associated circumstellar disk,...
We present maps at high spatial and spectral resolution in emission lines of CCH, c-C3H2, C4H, 12CO C18O the edge Horsehead nebula obtained with IRAM Plateau de Bure Interferometer (PdBI). The is a one-dimensional Photo-Dissociation Region (PDR) viewed almost edge-on. All hydrocarbons are detected signal-to-noise ratio PDR where intense seen both H2 ro-vibrational PAH mid-infrared bands. peaks farther away from cloud edge. Our observations demonstrate that c-C3H2 C4H UV-irradiated molecular...
We present a power spectrum analysis of the Herschel-SPIRE observations Polaris flare, high Galactic latitude cirrus cloud midway between diffuse and molecular phases. The SPIRE images flare reveal for first time structure interstellar medium down to 0.01 parsec over 10 square degrees region. These exceptional highlight highly filamentary clumpy even in regions map. shows that is well described by single law with an exponent -2.7 +- 0.1 at all scales from 30" 8 degrees. That slope dust...
Abstract Massive stars disrupt their natal molecular cloud material through radiative and mechanical feedback processes. These processes have profound effects on the evolution of interstellar matter in our Galaxy throughout universe, from era vigorous star formation at redshifts 1–3 to present day. The dominant can be probed by observations Photo-Dissociation Regions (PDRs) where far-ultraviolet photons massive create warm regions gas dust neutral atomic gas. PDR emission provides a unique...
(Abridged) Mid-infrared observations of photodissociation regions (PDRs) are dominated by strong emission features called aromatic infrared bands (AIBs). The most prominent AIBs found at 3.3, 6.2, 7.7, 8.6, and 11.2 $\mu$m. sensitive, highest-resolution spectral imaging data ever taken the prototypical PDR, Orion Bar, have been captured JWST. We provide an inventory in along with mid-IR template spectra from five distinct Bar: molecular atomic HII region. use JWST NIRSpec IFU MIRI MRS Bar...
Most low-mass stars form in stellar clusters that also contain massive stars, which are sources of far-ultraviolet (FUV) radiation. Theoretical models predict this FUV radiation produces photodissociation regions (PDRs) on the surfaces protoplanetary disks around affects planet formation within disks. We report James Webb Space Telescope and Atacama Large Millimeter Array observations a FUV-irradiated disk Orion Nebula. Emission lines detected from PDR; modeling their kinematics excitation...
We combine recent ISO observations of the vibrational ground state lines H 2 towards Photon-Dominated Regions (PDRs) with vibrationally excited states made ground-based telescopes in order to constrain formation rate on grain surfaces under physical conditions layers responsible for emission.We briefly review data available five nearby PDRs.We use steady PDR models examine sensitivity different line ratios R f .We show that ratio 0-0 S(3) 1-0 S(1) increases but one requires independent...
We use far-UV absorption spectra obtained with FUSE towards three late B stars to study the formation and excitation of H 2 in diffuse ISM.The data interpretation relies on a model chemical thermal balance photonilluminated gas.The constrain well n R product between gas density rate dust grains: = 1 2.2 × 10 -15 s -1 .For each line sight mean effective n, assumed uniform, is by best fit observed N(J 1)/N(J 0) ratio, since radiation field known.Combining values, we find similar rates for...
In bright photodissociation regions (PDRs) associated to massive star formation, the presence of dense "clumps" that are immersed in a less interclump medium is often proposed explain difficulty models account for observed gas emission high-excitation lines. We aim at presenting comprehensive view modeling CO rotational ladder PDRs, including high-J lines trace warm molecular PDR interfaces. 12CO and 13CO ladders two prototypical Orion Bar NGC 7023 NW using instruments onboard Herschel. also...
Context. Planet formation is expected to take place in the first million years of a planetary system through various processes, which remain be tested observations. Aims. With recent discovery, using ALMA, two gaseous spiral arms inside 120 au cavity and connected dusty spirals, famous protoplanetary disk around AB Aurigae presents strong incentive for investigating mechanisms that lead giant planet formation. A candidate protoplanet located arm has already been claimed an earlier study...
Context . The James Webb Space Telescope (JWST) has captured the most detailed and sharpest infrared (IR) images ever taken of inner region Orion Nebula, nearest massive star formation region, a prototypical highly irradiated dense photo-dissociation (PDR). Aims We investigate fundamental interaction far-ultraviolet (FUV) photons with molecular clouds. transitions across ionization front (IF), dissociation (DF), cloud are studied at high-angular resolution. These relevant to understanding...
Aims.Our aim is to determine the presence and location of emission from polycyclic aromatic hydrocarbons (PAHs) towards low intermediate mass young stars with disks using large aperture telescopes.
Although planets are being discovered around stars more massive than the Sun, information about proto-planetary disks where such have built up is sparse. We imaged mid-infrared emission from polycyclic aromatic hydrocarbons at surface of disk surrounding young intermediate-mass star HD 97048 and characterized disk. The in an early stage evolution, as indicated by its large content dust hydrostatic flared geometry, indicative presence a amount gas that well mixed with gravitationally stable....
<i>Aims. <i/>We present observations of the Orion Bar photodissociation region (PDR) obtained with SPIRE instrument on-board <i>Herschel<i/>. <i>Methods. Fourier-transform spectrometer (FTS) sparse sampled maps bar.<i>Results. <i/>The FTS wavelength coverage and sensitivity allow us to detect a wealth rotational lines CO (and its isotopologues), fine structure C N<sup>+<sup/>, emission from radicals molecules such as CH<sup>+<sup/>, CH, H<sub>2<sub/>O or H<sub>2<sub/>S. For species detected...
We present spectroscopic observations obtained with the infrared Spitzer Space Telescope, which provide insight into H$_2$ physics and gas energetics in photodissociation Regions (PDRs) of low to moderate far-ultraviolet (FUV) fields densities. analyze data on six well known Galactic PDRs (L1721, California, N7023E, Horsehead, rho Oph, N2023N), sampling a poorly explored range excitation conditions ($χ\sim 5-10^3$), relevant bulk molecular clouds galaxies. rotational lines are complemented...
Interstellar dust is a key element in our understanding of the interstellar medium and star formation. The manner which populations evolve with excitation physical conditions first step comprehension evolution inter- stellar dust. Within framework Evolution Herschel program, we have acquired PACS SPIRE spec- trophotometric observations various photodissociation regions, to characterise this evolution. aim paper trace grains Orion Bar region. We use Herschel/PACS (70 160 mic) (250, 350 500...
Context . Mid-infrared observations of photodissociation regions (PDRs) are dominated by strong emission features called aromatic infrared bands (AIBs). The most prominent AIBs found at 3.3, 6.2, 7.7, 8.6, and 11.2 µm. sensitive, highest-resolution spectral imaging data ever taken the prototypical PDR, Orion Bar, have been captured JWST. These high-quality allow for an unprecedentedly detailed view AIBs. Aims We provide inventory in along with mid-IR template spectra from five distinct Bar:...
Context . Nearby photo-dissociation regions (PDRs), where the gas and dust are heated by far-ultraviolet (FUV) irradiation emitted from stars, ideal templates with which to study main stellar feedback processes. Aims With this study, we aim probe detailed structures at interfaces between ionized, atomic, molecular in Orion Bar. This nearby prototypical strongly irradiated PDR among first targets of James Webb Space Telescope (JWST) within framework PDRs4All Early Release Science program....
We present imaging and spectroscopic observations of dust gas (H 2 ) emission, obtained with ISO, from the western edge ρ Ophiuchi molecular cloud illuminated by B2 star HD147889 (χ ∼ 400).This photodissociation region (PDR) is one nearest PDRs to Sun (d = 135 ± 15 pc stellar parallax) layer UV light penetration H emission spatially resolved.It therefore an ideal target test prediction models on integrated fluxes but also spatial distribution.The heated external radiation, collisionally...
Aims.Large ground-based instruments, like VISIR on the VLT, providing diffraction-limited (~0.3 arcsec) images in mid-infrared where strong PAH features appear, enable us to see flaring structure of disks around Herbig Ae stars. Although progress has been made modelling disk with radiative transfer models able reproduce spectral energy distribution (SED) stars, constraints brought by have not yet fully exploited. We investigate whether these new observational imaging can be accounted for...