A5114374378- Astrophysics and Star Formation Studies
- Molecular Spectroscopy and Structure
- Astro and Planetary Science
- Advanced Chemical Physics Studies
- Atmospheric Ozone and Climate
- Stellar, planetary, and galactic studies
- Planetary Science and Exploration
- Spacecraft and Cryogenic Technologies
- Atmospheric chemistry and aerosols
- Quantum, superfluid, helium dynamics
- Advanced Combustion Engine Technologies
- Atomic and Molecular Physics
- Space Exploration and Technology
- Spectroscopy and Laser Applications
- Astronomy and Astrophysical Research
- Galaxies: Formation, Evolution, Phenomena
- Astrophysics and Cosmic Phenomena
- Particle Detector Development and Performance
- Gamma-ray bursts and supernovae
- Astronomical Observations and Instrumentation
- Dark Matter and Cosmic Phenomena
- Mass Spectrometry Techniques and Applications
- Astrophysical Phenomena and Observations
- Scientific Research and Discoveries
- Geophysics and Gravity Measurements
Delft University of Technology
2017-2024
Leiden University
2015-2024
University of Michigan–Ann Arbor
2024
Leiden Observatory
2018-2023
Aircraft Development and Systems Engineering (Netherlands)
2019
Florence (Netherlands)
2019
Commissariat à l'Énergie Atomique et aux Énergies Alternatives
2005-2018
CEA Grenoble
2018
CEA Cadarache
2018
University of Groningen
2002-2017
Ground-based gamma-ray astronomy has had a major breakthrough with the impressive results obtained using systems of imaging atmospheric Cherenkov telescopes. huge potential in astrophysics, particle physics and cosmology. CTA is an international initiative to build next generation instrument, factor 5-10 improvement sensitivity 100 GeV 10 TeV range extension energies well below above TeV. will consist two arrays (one north, one south) for full sky coverage be operated as open observatory....
While warm dense gas is prevalent around low-mass protostars, the presence of complex saturated molecules—the chemical inventory characteristic hot cores—has remained elusive in such environments. Here we report results an IRAM 30 m study molecular composition associated with protostar IRAS 16293-2422. Our observations highlight extremely rich organic this source abundant amounts O- and N-bearing molecules as formic acid, HCOOH, acetaldehyde, CH3CHO, methyl formate, CH3OCHO, dimethyl ether,...
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...
The most abundant interstellar molecule, H2, is generally thought to form by recombination of H atoms on grain surfaces. On surfaces, hydrogen can be physisorbed and chemisorbed their mobility governed quantum mechanical tunneling or thermal hopping. We have developed a model for molecular formation This solves the time-dependent kinetic rate equation atomic isotopes, taking presence sites, as well diffusion hopping, into account. results show that time evolution this system mainly binding...
We report the detection of complex molecules (HCOOCH3, HCOOH, and CH3CN), signposts a hot core-like region, toward low-mass Class 0 source NGC 1333 IRAS 4A. This is second protostar in which such have been searched for reported, other being 16293-2422. It therefore likely that compact (a few tens AU) regions dense warm gas, where chemistry dominated by evaporation grain mantles are found, common sources. Given chemical formation timescale much shorter than gas hot-core crossing time, it not...
Context. The presence of dust in the interstellar medium has profound consequences on chemical composition regions where stars are forming. Recent observations show that many species formed onto populating gas phase, especially cold environments UV and CR induced photons do not account for such processes. Aims. aim this paper is to understand quantify process releases solid into so-called desorption process, so an explicit formula can be derived included astrochemical models. Methods. We...
In the environments where stars and planets form, about one percent of mass is in form micro-meter sized particles known as dust. However small insignificant these dust grains may seem, they are responsible for production simplest (H2) to most complex (amino-acids) molecules observed our Universe. Dust recognized powerful nano-factories that produce chemical species. However, mechanism converts species on gas remains elusive. Here we report experimental evidence forming interstellar analogs...
GEMS is an IRAM 30m Large Program whose aim determining the elemental depletions and ionization fraction in a set of prototypical star-forming regions. This paper presents first results from dark cloud TMC 1. Extensive millimeter observations have been carried out with telescope (3 mm 2 mm) 40m Yebes (1.3 cm 7 to determine fractional abundances CO, HCO
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...
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 have developed a model for molecular hydrogen formation under astrophysically relevant conditions. This takes fully into account the presence of both physisorbed and chemisorbed sites on surface, allows quantum mechanical diffusion as well thermal hopping absorbed H atoms, has been benchmarked versus recent laboratory experiments H2 silicate surfaces. The results show that grain surfaces is efficient in interstellar medium up to some 300 K. At low temperatures (≤100 K), governed by...
Complex organic molecules have previously been discovered in solar-type protostars, raising the questions of where and how they form envelope. Possible formation mechanisms include grain mantle evaporation, interaction outflow with its surroundings, and/or impact UV/X-rays inside cavities. In this Letter we present first interferometric observations two complex molecules, CH3CN HCOOCH3, toward protostar IRAS 16293-2422. The images show that emission originates from compact regions centered...
Context. Water together with O2 are important gas phase ingredients to cool dense in order form stars. On dust grains, H2 O is an constituent of the icy mantle which a complex chemistry taking place, as revealed by hot core observations. The formation water can occur on grain surfaces, and impact composition. Aims. molecules such OH, O, HO2, O2, well their deuterated forms O3 studied assess how varies different astrophysical environments, affected surface chemistry. Methods. We use Monte...
Molecules with an amide functional group resemble peptide bonds, the molecular bridges that connect amino acids, and may thus be relevant in processes lead to formation of life. In this study, solid state some smallest amides is investigated laboratory. To end, CH4:HNCO ice mixtures at 20 K are irradiated far-UV photons, where radiation used as a tool produce radicals required for amides. Products identified infrared spectroscopy temperature-programmed desorption mass spectrometry. The...
Sulphur is one of the most abundant elements in Universe. Surprisingly, sulphuretted molecules are not as expected interstellar medium, and identity main sulphur reservoir still an open question. Our goal to investigate H$_{2}$S chemistry dark clouds, this stable molecule a potential reservoir. Using millimeter observations CS, SO, H$_{2}$S, their isotopologues, we determine physical conditions abundances along cores TMC 1-C, 1-CP, Barnard 1b. The gas-grain model Nautilus then used explore...
Context. Sulfur is used as a tracer of the evolution from interstellar clouds to stellar systems. However, most expected sulfur in molecular remains undetected. disappears gas phase two steps. One first depletion occurs during translucent phase, reducing by 7-40 times, while following freeze-out step clouds, it another order magnitude. This long-standing dilemma awaits an explanation. Aims. The aim this study understand under which form missing hiding clouds. Depletion onto dust grains...
Context. Gas phase Elemental abundances in molecular CloudS (GEMS) is an IRAM 30-m Large Program aimed at determining the elemental of carbon (C), oxygen (O), nitrogen (N), and sulfur (S) a selected set prototypical star-forming filaments. In particular, abundance S remains uncertain by several orders magnitude, its determination one most challenging goals this program. Aims. This paper aims to constrain Taurus, Perseus, Orion A based on GEMS database. The regions are prototypes low-mass,...
(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...
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:...
<i>Context. <i/>HD and H<sub>2<sub/> molecules play important roles in the cooling of primordial very metal-poor gas at high redshift.<i>Aims. <i/>Grain surface phase formation HD are investigated to assess importance trace amounts dust, 10<sup>-5<sup/>-10<sup>-3<sup/> , production H<sub>2<sub/>.<i>Methods. <i/>We consider carbonaceous silicate grains include both physisorption chemisorption, tunneling, realistic grain barriers. We find that, for a collapsing cloud environment with coupled...
The temperature of interstellar dust particles is great importance to astronomers. It plays a crucial role in the thermodynamics clouds, because gas-dust collisional coupling. also key parameter astrochemical studies that governs rate at which molecules form on dust. In 3D (magneto)hydrodynamic simulations often simple expression for adopted, computational constraints, while modelers tend keep constant over large range space. Our aim provide an easy-to-use parametric as function visual...