A5009388600- Astrophysics and Star Formation Studies
- Stellar, planetary, and galactic studies
- Atmospheric Ozone and Climate
- Galaxies: Formation, Evolution, Phenomena
- Astro and Planetary Science
- Astronomy and Astrophysical Research
- Molecular Spectroscopy and Structure
- Astrophysics and Cosmic Phenomena
- Gamma-ray bursts and supernovae
- Atomic and Molecular Physics
- Scientific Research and Discoveries
- Spectroscopy and Laser Applications
- Fluid Dynamics Simulations and Interactions
- Astrophysical Phenomena and Observations
- Dark Matter and Cosmic Phenomena
- Solar and Space Plasma Dynamics
- Atmospheric chemistry and aerosols
- Radiomics and Machine Learning in Medical Imaging
- Advanced Combustion Engine Technologies
- Quantum, superfluid, helium dynamics
- Cold Atom Physics and Bose-Einstein Condensates
- Gas Dynamics and Kinetic Theory
- Impact of Light on Environment and Health
- Particle Detector Development and Performance
- Radiation Therapy and Dosimetry
Zhejiang Lab
2022-2025
University of Cologne
2019-2023
Aristotle University of Thessaloniki
2019-2023
National Observatory of Athens
2019-2022
Max Planck Institute for Extraterrestrial Physics
2015-2019
University of Florida
2015-2018
University of Virginia
2018
University College London
2010-2016
KTH Royal Institute of Technology
2015
Nordic Institute for Theoretical Physics
2015
Feedback from massive stars is believed to be a key element in the evolution of molecular clouds. We use high-resolution 3D smoothed particle hydrodynamics simulations explore dynamical effects single O7 star-emitting ionizing photons at 1049 s−1 and located centre cloud with mass 104 M⊙ radius 6.4 pc; we also perform comparison which star removed. The initial internal structure characterized by its fractal dimension, vary between 2.8, standard deviation approximately log-normal density PDF,...
We report on the effects of cosmic rays (CRs) abundance CO in H2 clouds under conditions typical for star-forming galaxies universe. discover that this most important molecule tracing gas is very effectively destroyed ISM environments with CR energy densities , a range expected numerous systems throughout This density-dependent effect operates volumetrically rather than only molecular cloud surfaces (i.e., unlike FUV radiation also destroys CO), and facilitated by (a) direct destruction CRs...
We estimate the mass-loss rates of photoevaporative winds launched from outer edge protoplanetary discs impinged by an ambient radiation field. focus on mild/moderate environments (the number stars in group/cluster is N ≳ 50), and explore disc sizes ranging between 20 250 au. evaluate steady-state structures coupling temperature estimates obtained with a photodissociation region code 1D radial hydrodynamical equations. also consider impact dust dragging grain growth final rates. find that...
We present Atacama Large Millimeter Array [C i](1 − 0) (rest frequency 492 GHz) observations for a sample of 13 strongly lensed dusty star-forming galaxies (DSFGs) originally discovered at 1.4 mm in blank-field survey by the South Pole Telescope (SPT). compare these new data with available i] from literature, allowing study interstellar medium (ISM) properties ∼30 extreme DSFGs spanning redshift range 2 < z 5. Using line as tracer molecular ISM, we find mean gas mass SPT-DSFGs 6.6 × 1010 M⊙....
We explore the effects of expected higher cosmic ray (CR) ionization rates $\zeta_{\rm CR}$ on abundances carbon monoxide (CO), atomic (C), and ionized (C$^+$) in H$_2$ clouds star-forming galaxies. The study Bisbas et al. (2015) is expanded by: a) using realistic inhomogeneous Giant Molecular Cloud (GMC) structures, b) a detailed chemical analysis behind CR-induced destruction CO, c) exploring thermal state CR-irradiated molecular gas. CRs permeating interstellar medium with CR}$$\gtrsim...
We study the dynamics of cold molecular gas in two main-sequence galaxies at cosmic noon (zC-488879 $z\simeq1.47$ and zC-400569 $z\simeq2.24$) using new high-resolution ALMA observations multiple $^{12}$CO transitions. For we also re-analyze high-quality H$\alpha$ data from SINS/zC-SINF survey. find that (1) Both have regularly rotating CO disks their rotation curves are flat out to $\sim$8 kpc contrary previous results pointing outer declines speed $V_{\rm rot}$; (2) The intrinsic velocity...
Aims.We introduce and test a new highly efficient method for treating the thermal radiative effects influencing energy equation in SPH simulations of star formation.
We present simulations of initially stable isothermal clouds exposed to ionising radiation from a discrete external source, and identify the conditions that lead radiatively driven implosion star formation. use Smoothed Particle Hydrodynamics code SEREN an HEALPix-based photo-ionisation algorithm simulate propagation resulting dynamical evolution cloud. find incident flux, $\Phi_{_{\rm LyC}}$, is critical parameter determining cloud evolution. At moderate fluxes, large fraction mass...
Photodissociation regions (PDRs) define the transition zone between an ionized and a dark molecular region. They consist of neutral gas which interacts with far-ultraviolet radiation are characterized by strong infrared line emission. Various numerical codes treating one-dimensional PDRs have been developed in past, simulating complexity chemical reactions occurring providing better understanding structure PDR. In this paper we present three-dimensional code, 3D-PDR, can treat arbitrary...
starbench is a project focused on benchmarking and validating different star formation stellar feedback codes. In this first paper we perform comparison study of the D-type expansion an H ii region. The aim work to understand differences observed between 12 participating numerical codes against various analytical expressions examining phase region expansion. To do this, propose two well-defined tests which are tackled by 1D 3D grid- smoothed particle hydrodynamics-based test examines 'early...
Infrared shells and bubbles are ubiquitous in the Galaxy can generally be associated with H ii regions formed around young, massive stars. In this paper, we use high-resolution 3D SPH simulations to explore effect of a single O7 star emitting photons at 1049 s−1 located centre molecular cloud mass 104 M⊙ radius 6.4 pc; internal structure is characterized by its fractal dimension, |${\cal D}$| (with |$2.0\le {\cal D}\le 2.8$|), variance (lognormal) density distribution, |$\sigma _{{\rm...
We explore the utility of CI as an alternative high-fidelity gas mass tracer for Galactic molecular clouds. evaluate X$_{\rm CI}$-factor 609 $\mu$m carbon line, analog CO X-factor, which is ratio H$_2$ column density to integrated $^{12}$CO(1-0) line intensity. use 3D-PDR post-process hydrodynamic simulations turbulent, star-forming compare emission and model clouds irradiated by 1 10 times average background demonstrate that a comparable or superior distribution densities up $6 \times...
We analyse the CO-dark molecular gas content of simulated clouds from SILCC-Zoom project. The simulations reach a resolution 0.1 pc and include H$_2$ CO formation, radiative stellar feedback magnetic fields. is found in regions with local visual extinctions $A_\text{V, 3D} \sim$ 0.2 - 1.5, number densities 10 10$^{3}$ cm$^{-3}$ temperatures few K 100 K. CO-bright at above 300 below 50 fractions range 40% to 95% scale inversely amount well-shielded ($A_\text{V, 3D}$ $\gtrsim$ 1.5), which...
<i>Context. <i/>Ionizing radiation plays a crucial role in star formation at all epochs. In contemporary formation, ionization abruptly raises the pressure by more than three orders of magnitude; temperature increases from ~ to ~, and mean molecular weight decreases factor 3. This may result positive feedback, either compressing pre-existing clouds rendering them unstable, or sweeping up gravitationally unstable shells. It also negative feedback (by dispersing residual dense gas). Ionizing...
In this work we extend the on recently discovered role of Cosmic Rays (CRs) in regulating average CO/$\rm H_2$ abundance ratio molecular clouds (and thus their CO line visibility) starburst galaxies, and find that it can lead to a CO-poor/CI-rich $\rm H_2 $ gas phase even environments with Galactic or only modestly enhanced CR backgrounds expected ordinary star-forming galaxies. Furthermore, same CR-driven astro-chemistry raises possibility widespread transition towards in: a) outflows found...
We present calculations of molecular, atomic and ionic line emission from simulations giant molecular cloud (GMC) collisions. post-process snapshots the magneto-hydrodynamical presented in an earlier paper this series by Wu et al. (2017) colliding non-colliding GMCs. Using photodissociation region (PDR) chemistry radiative transfer we calculate level populations properties $^{12}$CO $J=1-0$, [CI] $^3{\rm P}_1\rightarrow{^3{\rm P}}_0$ at $609\,μ$m, [CII] $158\,μ$m [OI] transition $63\,μ$m....
We present three-dimensional astrochemical simulations and synthetic observations of magnetised, turbulent, self-gravitating molecular clouds. explore various galactic interstellar medium environments, including cosmic-ray ionization rates in the range $ζ_{\rm CR}=10^{-17}$-$10^{-14}\,{\rm s}^{-1}$, far-UV intensities $G_0=1$-$10^3$ metallicities $Z=0.1$-$2\,{\rm Z}_{\odot}$. The also probe a densities levels turbulence, cases where gas has undergone recent compression due to cloud-cloud...
Massive clumps within the swept-up shells of bubbles, like that surrounding galactic HII region RCW 120, have been interpreted in terms Collect and Collapse (C&C) mechanism for triggered star formation. The cold, dusty 120 are arranged an almost spherical shell harbour many young stellar objects. By performing high-resolution, three-dimensional SPH simulations regions expanding into fractal molecular clouds, we investigate whether formation massive dense, necessarily requires C&C mechanism....
Abstract We present astrochemical photodissociation region models in which cosmic-ray (CR) attenuation has been fully coupled to the chemical evolution of gas. model impact CRs, including those accelerated by protostellar accretion shocks, on molecular clouds hosting protoclusters. Our with embedded protostars reproduce observed ionization rates. study imprint CR ions for different surface spectra and star formation efficiencies. find that abundances, particularly ions, are sensitive...
Abstract Ions (e.g., <?CDATA ${{\rm{H}}}_{3}^{+}$?> <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:msubsup> <mml:mrow> <mml:mi mathvariant="normal">H</mml:mi> </mml:mrow> <mml:mn>3</mml:mn> <mml:mo>+</mml:mo> </mml:msubsup> </mml:math> , H 2 O + ) have been used extensively to quantify the cosmic-ray ionization rate (CRIR) in diffuse sightlines. However, measurements of CRIR low-to-intermediate density gas environments are rare, especially when background...
The [C ii] 158 μm emission line can arise in all phases of the interstellar medium (ISM), therefore being able to disentangle different contributions is an important yet unresolved problem when undertaking galaxy-wide, integrated observations. We present a new multiphase 3D radiative transfer interface that couples starburst99, stellar spectrophotometric code, with photoionization and astrochemistry codes mocassin 3d-pdr. model entire star-forming regions, including ionized, atomic,...
Context. Carbon monoxide (CO) is widely used as a tracer of the molecular gas in almost all types environments. However, several shortcomings CO complicate usaging it H2 tracer, such its optical depth effects, dependence abundance on metallicity, or susceptibility to dissociation highly irradiated regions. Neutral carbon emission has been proposed overcome some these and hence help revealing limits measure gas.
Determining the atomic and molecular content of interstellar medium (ISM) as a function environmental parameters is fundamental importance to understand star-formation process across epochs. Although there exist various three-dimensional hydro-chemical codes modelling ISM at different scales redshifts, they are computationally expensive inefficient for studies over large parameter space. Building on our earlier approach, we present PDFchem, novel algorithm that models cold moderate using...