A5020685524- Astrophysics and Star Formation Studies
- Stellar, planetary, and galactic studies
- Atmospheric Ozone and Climate
- Molecular Spectroscopy and Structure
- Galaxies: Formation, Evolution, Phenomena
- Spectroscopy and Laser Applications
- Astro and Planetary Science
- Astrophysical Phenomena and Observations
- Advanced Chemical Physics Studies
- Atomic and Molecular Physics
- Atmospheric and Environmental Gas Dynamics
- Gamma-ray bursts and supernovae
- Advanced Combustion Engine Technologies
- Particle physics theoretical and experimental studies
- Neutrino Physics Research
- Astronomy and Astrophysical Research
- Atmospheric chemistry and aerosols
- Atomic and Subatomic Physics Research
- Astrophysics and Cosmic Phenomena
- Spacecraft and Cryogenic Technologies
- Nuclear Physics and Applications
- Astronomical Observations and Instrumentation
- Structural and Chemical Analysis of Organic and Inorganic Compounds
- Granular flow and fluidized beds
- Aerospace Engineering and Energy Systems
Goethe University Frankfurt
2002-2024
University of Cologne
2012-2024
RIKEN
2024
Pioneer (Japan)
2024
Karlsruhe Institute of Technology
2021-2023
Ghent University
2022
University of Bonn
2006-2008
Aims.We present a comparison between independent computer codes, modeling the physics and chemistry of interstellar photon dominated regions (PDRs). Our goal was to understand mutual differences in PDR codes their effects on physical chemical structure model clouds, converge output different common solution.
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...
We study the effects of a metallicity variation on thermal balance and [CII] fine-structure line strengths in interstellar photon dominated regions (PDRs). find that reduction dust-to-gas ratio abundance heavy elements gas phase changes heat PDRs. The surface temperature PDRs decreases as except for high density ( cm-3) clouds exposed to weak () FUV fields where vibrational H2-deexcitation heating dominates over photoelectric gas. incorporate dependence our KOSMA-τ PDR model [CII]/CO ratios...
We present the first ~7.5'×11.5' velocity-resolved (~0.2 km s-1) map of [C ii] 158 μm line toward Orion molecular cloud 1 (OMC 1) taken with Herschel/HIFI instrument. In combination far-infrared (FIR) photometric images and maps H41α hydrogen recombination CO J=2-1 lines, this data set provides an unprecedented view intricate small-scale kinematics ionized/PDR/molecular gas interfaces radiative feedback from massive stars. The main contribution to luminosity (~85 %) is extended,...
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 present high resolution large scale observations of the molecular and atomic gas in Local Group Galaxy M33. The were carried out using HERA at 30m IRAM telescope CO(2-1) line achieving a 12"x2.6 km/s, enabling individual GMCs to be resolved. observed region mainly along major axis radius 8.5 kpc, covers strip with HIFI/PACS Spectrometers as part HERM33ES Herschel key program. achieved sensitivity main beam temperature is 20-50 mK 2.6 km/s velocity resolution. luminosity 1.7\pm0.1x10^7...
We present an analysis of the systematic CO(2-1) survey at 12" resolution covering most local group spiral M 33 which, a distance 840 kpc, is close enough that individual giant molecular clouds (GMCs) can be identified. The goal this work to study properties GMCs in subsolar metallicity galaxy. CPROPS (Cloud Properties) algorithm (Rosolowsky & Leroy 2006) was used identify 337 33, largest sample date external GMC luminosity function, or mass spectrum under assumption constant N(H2)/ICO...
Recently, we introduced detailed isotopic chemistry into the KOSMA-tau model for photon-dominated regions (PDRs) to give theoretical predictions abundance of carbon isotopologues as a function PDR parameters. Combined with radiative transfer computations specific geometries, estimated possible intensity ratio [CII]/[13CII] lines. Here, compare these new observations. We performed Herschel/HIFI observations [CII] 158micron line in number PDRs. In all sources observed at least two hyperfine...
The abundances of interstellar CH+ and SH+ are not well understood as their most likely formation channels highly endothermic. Using data from Herschel, we study the in a typical high UV-illumination photon-dominated region (PDR), Orion Bar. Herschel/HIFI provides velocity-resolved 1-0 2-1 three hyperfine transitions SH+. Herschel/PACS information on excitation spatial distribution (up to J=6-5). widths ~5 km/s, significantly broader than width dense gas tracers Bar (2-3 km/s) comparable...
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...
(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 . 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...
<i>Aims. <i/> We identify a prominent absorption feature at 1115 GHz, detected in first HIFI spectra towards high-mass star-forming regions, and interpret its astrophysical origin. <i>Methods. The characteristic hyperfine pattern of the H<sub>2<sub/>O<sup>+<sup/> ground-state rotational transition, lack other known low-energy transitions this frequency range, identifies as against dust continuum background allows us to derive velocity profile absorbing gas. By comparing with profiles tracers...
Within the framework of HERM33ES key project, we are studying star forming interstellar medium in nearby, metal-poor spiral galaxy M33, exploiting high resolution and sensitivity Herschel. We use PACS SPIRE maps at 100, 160, 250, 350, 500 micron wavelength, to study variation spectral energy distributions (SEDs) with galacto-centric distance. Detailed SED modeling is performed using azimuthally averaged fluxes elliptical rings 2 kpc width, out 8 Simple isothermal two-component grey body...
We upgraded the chemical network from UMIST Database for Astrochemistry 2006 to include isotopes such as ^{13}C and ^{18}O. This includes all corresponding isotopologues, their reactions properly scaled reaction rate coefficients. study fractionation behavior of astrochemically relevant species over a wide range model parameters, modelling photo-dissociation regions (PDRs). separately analyze local abundances, total column densities, visible in emission line ratios. find that strong C^+ is...
Power spectra of deprojected images late-type galaxies in gas or dust emission are very useful diagnostics the dynamics and stability their interstellar medium. Previous studies have shown that power can be approximated as two laws, a shallow one on large scales (larger than 500 pc) steeper small scales, with break between corresponding to line-of-sight thickness galaxy disk. The separates 3D behavior medium controlled by star formation feedback, from 2D driven density waves these regimes...
We study the wavelength dependence of dust emission as a function position and environment across disk M33 at linear resolution 160 pc using Spitzer Herschel photometric data. Expressing emissivity power law, power-law exponent (beta) is estimated from two independent approaches designed to properly treat degeneracy between beta temperature. Both temperature are higher in inner than outer disk, contrary reported beta-T anti-correlations found other sources. In cold + warm model, component...
As part of a far-infrared (FIR) spectral scan with Herschel/PACS, we present the first detection hydroxyl radical (OH) towards Orion Bar photodissociation region (PDR). Five OH rotational Lambda-doublets involving energy levels out to E_u/k~511 K have been detected (at ~65, ~79, ~84, ~119 and ~163um). The total intensity lines is I(OH)~5x10^-4 erg s^-1 cm^-2 sr^-1. observed emission rotationally excited extended correlates well high-J CO CH^+ J=3-2 line (but apparently not water vapour),...
The radiative feedback of massive stars on molecular clouds creates pillars, globules and other features at the interface between HII region cloud. We present here Herschel observations 70 500 micron immediate environment Cygnus OB2 association, performed within HOBYS program. All structures were detected based their appearance micron, have been classified as globules, evaporating gasous (EGGs), proplyd-like objects, condensations. From 160 flux maps, we derive local FUV field PDR surfaces....
FEEDBACK is a SOFIA legacy program dedicated to study the interaction of massive stars with their environment. It performs survey 11 galactic high mass star forming regions in 158 $μ$m (1.9 THz) line CII and 63 (4.7 OI. We employ 14 pixel LFA 7 HFA upGREAT instrument spectrally resolve (0.24 MHz) these FIR structure lines. With an observing time 96h, we will cover $\sim$6700 arcmin$^2$ at 14.1$''$ angular resolution for 6.3$''$ OI line. The observations started spring 2019 (Cycle 7). Our aim...