A5045314886- Astrophysics and Star Formation Studies
- Stellar, planetary, and galactic studies
- Galaxies: Formation, Evolution, Phenomena
- Astrophysical Phenomena and Observations
- Molecular Spectroscopy and Structure
- Astro and Planetary Science
- Astronomy and Astrophysical Research
- Astronomical Observations and Instrumentation
- Atmospheric Ozone and Climate
- Spectroscopy and Laser Applications
- Astrophysics and Cosmic Phenomena
- Atomic and Molecular Physics
- Calibration and Measurement Techniques
- Gamma-ray bursts and supernovae
- Radio Astronomy Observations and Technology
- Photonic and Optical Devices
- Atmospheric chemistry and aerosols
- Optical Network Technologies
- Advanced Thermodynamic Systems and Engines
- Advanced Photonic Communication Systems
- Phase Equilibria and Thermodynamics
- Planetary Science and Exploration
- Space Exploration and Technology
- Mechanical and Optical Resonators
- Advanced Fiber Laser Technologies
Leiden University
2007-2018
Leiden Observatory
2003-2016
University of Groningen
2012-2016
Astronomy and Space
2011-2013
Astronomical Institute of the Slovak Academy of Sciences
2012
California Institute of Technology
2009-2010
University of California, Berkeley
2007-2009
University of Twente
2007-2009
We present a far-ultraviolet (PDR) and an X-ray dominated region (XDR) code. include discuss thermal chemical processes that pertain to irradiated gas. An elaborate network is used careful treatment of PAHs H2 formation, destruction excitation included. For both codes we calculate four depth-dependent models for different densities radiation fields, relevant conditions in starburst galaxies active galactic nuclei. A detailed comparison between PDR XDR physics made total gas column ~1020...
Aims.The nuclei of active galaxies harbor massive young stars, an accreting central black hole, or both. In order to determine the physical conditions that pertain molecular gas close sources radiation, numerical models are constructed.
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.
We present a full high resolution SPIRE FTS spectrum of the nearby ultraluminous infrared galaxy Mrk231. In total 25 lines are detected, including CO J=5-4 through J=13-12, 7 rotational H2O, 3 OH+ and one line each H2O+, CH+, HF. find that excitation levels up to J=8 can be accounted for by UV radiation from star formation. However, approximately flat luminosity distribution over ladder above requires presence separate source highest lines. explore X-ray heating accreting supermassive black...
We propose a set of standard assumptions for the modelling Class II and III protoplanetary disks, which includes detailed continuum radiative transfer, thermo-chemical gas ice, line transfer from optical to cm wavelengths. new dust opacities disk models, we present simplified treatment PAHs sufficient reproduce PAH emission features, suggest using simple settling. roughly adjust parameters obtain model that predicts typical T Tauri star observations. systematically study impact each...
We present a catalogue of nearly 3,000 submillimetre sources detected at 850um over ~5 square degrees surveyed as part the James Clerk Maxwell Telescope (JCMT) SCUBA-2 Cosmology Legacy Survey (S2CLS). This is largest survey its kind 850um, probing meaningful cosmic volume peak star formation activity and increasing sample size galaxies selected by an order magnitude. describe wide component S2CLS, which covers key extragalactic fields: UKIDSS-UDS, COSMOS, Akari-NEP, Extended Groth Strip,...
We present the first results of a survey [CII]158um emission line in 241 luminous infrared galaxies (LIRGs) comprising Great Observatories All-sky Survey (GOALS) sample, obtained with PACS instrument on board Herschel. The [CII] luminosities LIRGs GOALS range from ~10^7 to 2x10^9 Lsun. find that show tight correlation [CII]/FIR far-IR flux density ratios, strong negative trend spanning ~10^-2 10^-4, as average temperature dust increases. correlations between ratio and strength 9.7um silicate...
We present high-resolution (0.3'') ALMA 870um imaging of 52 sub-millimeter galaxies (SMGs) in the Ultra Deep Survey (UDS) field and investigate size morphology (sub-mm) emission on 2-10kpc scales. derive a median intrinsic angular FWHM=0.30$\pm$0.04'' for 23 SMGs sample detected at signal-to-noise ratio (SNR) >10. Using photometric redshifts we show that this corresponds to physical half-light diameter 2.4$\pm$0.2kpc. A stacking analysis an SNR <10 shows they have sizes consistent with...
A novel optical beamformer concept is introduced that can be used for seamless control of the reception angle in broadband wireless receivers employing a large phased array antenna (PAA). The core this an beamforming network (OBFN), using ring resonator-based delays, and coherent combining. electro-optical conversion performed by means single-sideband suppressed carrier modulation, common laser, Mach-Zehnder modulators, sideband filter after OBFN. unmodulated laser signal then re-injected...
We present high-resolution 870-um ALMA continuum maps of 30 bright sub-millimeter sources in the UKIDSS UDS field. These are selected from deep, 1-square degrees 850-um SCUBA--2 Cosmology Legacy Survey, and representative brightest field (median SCUBA2 flux S_850=8.7+/-0.4 mJy). detect 52 galaxies (SMGs) at >4-sigma significance our maps. In 61+/-17% single-dish source comprises a blend >=2 SMGs, where secondary SMGs Ultra--Luminous Infrared Galaxies (ULIRGs) with L_IR>10^12 Lo. The SMG...
We present FIR [50–300 μm]−CO luminosity relations (i.e., ) for the full CO rotational ladder from J = 1–0 up to 13–12 a sample of 62 local (z ⩽ 0.1) (Ultra) Luminous Infrared Galaxies (LIRGs; LIR[8-1000 μm] > 1011 L☉) using data Herschel SPIRE-FTS and ground-based telescopes. extend our high redshifts 1) by including 35 submillimeter selected dusty star forming galaxies literature with robust observations, sufficiently well-sampled FIR/submillimeter spectral energy distributions (SEDs), so...
Context: Molecular data of extreme environments, such as Arp 220, but also NGC 253, show evidence for extremely high cosmic ray (CR) rates (10^3-10^4 * Milky Way) and mechanical heating from supernova driven turbulence. Aims: The consequences CR on the chemistry in clouds are explored. Methods: PDR model predictions made low, n=10^3, high, n=10^5.5 cm^-3, density using well-tested radiation transfer codes. Column densities relevant species discussed, special attention is given to water...
We present a Spitzer InfraRed Spectrometer search for 10–36 μm molecular emission from large sample of protoplanetary disks, including lines H2O, OH, C2H2, HCN, and CO2. This paper describes the data processing derives detection rate mid-infrared as function stellar mass. The covers range spectral type early M to A, is supplemented by archival spectra disks around A B stars. It drawn variety nearby star-forming regions, Ophiuchus, Lupus, Chamaeleon. Spectra showing strong are used identify...
We present Herschel SPIRE FTS spectroscopy of the nearby luminous infrared galaxy NGC 6240. In total 20 lines are detected, including CO J = 4 − 3 through 13 12, 6 H2O rotational lines, and [C i] [N ii] fine-structure lines. The to continuum luminosity ratio is 10 times higher in 6240 than Mrk 231. Although ladders 231 very similar, UV and/or X-ray irradiation unlikely be responsible for excitation gas applied both C shock models H2 v 1–0 S(1) 2–1 ladder. ladder best reproduced by a model...
We discuss the chemical pre-conditions for planet formation, in terms of gas and ice abundances a protoplanetary disk, as function time position, resulting composition cloud properties atmosphere when young giant planets form, particular discussing effects unusual, non-solar carbon oxygen abundances. Large deviations between host star its giants seem likely to occur if formation follows core-accretion scenario. These stem from separate evolution dust where forms cores, followed by final...
The first deep blank-field 450um map (1-sigma~1.3mJy) from the SCUBA-2 Cosmology Legacy Survey (S2CLS), conducted with James Clerk Maxwell Telescope (JCMT) is presented. Our covers 140 arcmin^2 of COSMOS field, in footprint HST CANDELS area. Using 60 submillimetre galaxies (SMGs) detected at >3.75-sigma, we evaluate number counts 450um-selected flux densities S_450>5mJy. 8-arcsec JCMT beam and high sensitivity now make it possible to directly resolve a larger fraction cosmic infrared...
(Ultra) luminous infrared galaxies ((U)LIRGs) are objects characterized by their extreme (8–1000 μm) luminosities (LLIRG > 1011 L☉ and LULIRG 1012 L☉). The Herschel Comprehensive ULIRG Emission Survey (PI: van der Werf) presents a representative flux-limited sample of 29 (U)LIRGs that spans the full luminosity range these (1011L☉ ⩽ LIR 1013L☉). With Space Observatory, we observe [C ii] 157 μm, [O i] 63 145 μm line emission with Photodetector Array Camera Spectrometer, CO J = 4–3 through...
The structures and dynamics of molecular, atomic, ionized gases are studied around a low-luminosity active galactic nucleus (AGN) with small ($2\times 10^6 M_\odot$) black hole using 3D radiation hydrodynamic simulations. We studied, for the first time, non-equilibrium chemistry X-ray dominated region in "radiation-driven fountain" (Wada 2012) supernova feedback. A double hollow cone structure is naturally formed without postulating thick "torus" central source. occupied an inhomogeneous,...
The gas-phase chemistry of water in protoplanetary disks is analyzed with a model based on X-ray heating and ionization the disk atmosphere. Several uncertain processes appear to play critical roles generating column densities warm that are detected from at infrared wavelengths. dominant factors reactions form molecular hydrogen, including formation grains, All these can work together produce region high abundances transition layer inner atmosphere, where atoms transformed into molecules,...
Water is key in the evolution of protoplanetary disks and formation comets icy/water planets. While high excitation water lines originating hot inner disk have been detected several T Tauri stars (TTSs), vapor from outer disk, where most ice reservoir stored, was only reported closeby TTS TW Hya. We present spectrally resolved Herschel/HIFI observations young DG Tau ortho- para- ground-state transitions at 557, 1113 GHz. The show a narrow double-peaked profile, consistent with an origin are...
Abstract We present ALMA band 3 observations of the CO(6–5), CO(7–6), and [C i ] 369 μ m emission lines in three highest-redshift quasar host galaxies at <?CDATA $6.6\lt z\lt 6.9$?> . These measurements constitute CO detections to date. The target quasars have previously been detected ii 158 underlying FIR dust continuum. detect (spatially unresolved, a resolution >2″, or ≳14 kpc) all hosts. In two sources, we continuum around 400 (rest-frame), one source low significance. derive...
We present new [CI](1-0) and 12CO(4-3) Plateau de Bure Interferometer observations of five Sub-Millimeter Galaxies (SMGs) combine these with all available literature detections in SMGs to probe the gas distribution within a sample 14 systems. explore properties SMG population, particularly investigating ratio luminosity various 12CO transition far-infrared luminosities. find that extend spread L[CI](1-0)/LFIR much higher values than found before, our complete providing good representation...