scholarly journals Photoevaporation of the Jovian circumplanetary disk

2020 ◽  
Vol 638 ◽  
pp. A135 ◽  
Author(s):  
N. Oberg ◽  
I. Kamp ◽  
S. Cazaux ◽  
Ch. Rab
Keyword(s):  
Radiation Field ◽  
Critical Mass ◽  
Incident Radiation ◽  
Outer Radius ◽  
Galilean Satellites ◽  
Stellar Cluster ◽  
Annular Gap ◽  
Hydrodynamical Simulations ◽  
Galilean System ◽  
Far Ultraviolet

Context. The Galilean satellites are thought to have formed from a circumplanetary disk (CPD) surrounding Jupiter. When it reached a critical mass, Jupiter opened an annular gap in the solar protoplanetary disk that might have exposed the CPD to radiation from the young Sun or from the stellar cluster in which the Solar System formed. Aims. We investigate the radiation field to which the Jovian CPD was exposed during the process of satellite formation. The resulting photoevaporation of the CPD is studied in this context to constrain possible formation scenarios for the Galilean satellites and explain architectural features of the Galilean system. Methods. We constructed a model for the stellar birth cluster to determine the intracluster far-ultraviolet (FUV) radiation field. We employed analytical annular gap profiles informed by hydrodynamical simulations to investigate a range of plausible geometries for the Jovian gap. We used the radiation thermochemical code PRODIMO to evaluate the incident radiation field in the Jovian gap and the photoevaporation of an embedded 2D axisymmetric CPD. Results. We derive the time-dependent intracluster FUV radiation field for the solar birth cluster over 10 Myr. We find that intracluster photoevaporation can cause significant truncation of the Jovian CPD. We determine steady-state truncation radii for possible CPDs, finding that the outer radius is proportional to the accretion rate Ṁ0.4. For CPD accretion rates Ṁ < 10−12M⊙ yr−1, photoevaporative truncation explains the lack of additional satellites outside the orbit of Callisto. For CPDs of mass MCPD < 10−6.2M⊙, photoevaporation can disperse the disk before Callisto is able to migrate into the Laplace resonance. This explains why Callisto is the only massive satellite that is excluded from the resonance.

scholarly journals Radiative Feedback Effects during Cosmic Reionization

2014 ◽  
Vol 11 (S308) ◽  
pp. 372-377
Author(s):  
David Sullivan ◽  
Ilian T. Iliev
Keyword(s):  
Star Formation ◽  
Radiation Field ◽  
Early Universe ◽  
Galaxy Formation ◽  
Analytical Models ◽  
Feedback Effects ◽  
Radiative Feedback ◽  
Hydrodynamical Simulations ◽  
Matching Models ◽  
The Impact

AbstractWe present coupled radiation hydrodynamical simulations of the epoch of reionization, aimed at probing self-feedback on galactic scales. Unlike previous works, which assume a (quasi) homogeneous UV background, we self-consistently evolve both the radiation field and the gas to model the impact of previously unresolved processes such as spectral hardening and self-shielding. We find that the characteristic halo mass with a gas fraction half the cosmic mean, Mc(z), a quantity frequently used in semi-analytical models of galaxy formation, is significantly larger than previously assumed. While this results in an increased suppression of star formation in the early Universe, our results are consistent with the extrapolated stellar abundance matching models from Moster et al. 2013.

scholarly journals Radiative cooling rates, ion fractions, molecule abundances, and line emissivities including self-shielding and both local and metagalactic radiation fields

2020 ◽  
Vol 497 (4) ◽  
pp. 4857-4883 ◽  
Author(s):  
Sylvia Ploeckinger ◽  
Joop Schaye
Keyword(s):  
Cosmic Rays ◽  
Radiation Field ◽  
Spectral Synthesis ◽  
Cosmic Ray ◽  
Cooling Rates ◽  
Radiation Fields ◽  
Hydrodynamical Simulations ◽  
Lower Temperature ◽  
X Ray Background ◽  
Ionization Balance

ABSTRACT We use the spectral synthesis code cloudy to tabulate the properties of gas for an extensive range in redshift (z = 0–9), temperature (log T[K] = 1–9.5), metallicity (log Z/Z⊙ = −4 – +0.5, Z = 0), and density ($\log n_{\mathrm{H}}[\, \mathrm{cm}^{-3}] = -8$ − +6). This therefore includes gas with properties characteristic of the interstellar, circumgalactic, and intergalactic media. The gas is exposed to a redshift-dependent UV/X-ray background, while for the self-shielded lower-temperature gas (i.e. ISM gas), an interstellar radiation field and cosmic rays are added. The radiation field is attenuated by a density- and temperature-dependent column of gas and dust. Motivated by the observed star formation law, this gas column density also determines the intensity of the interstellar radiation field and the cosmic ray density. The ionization balance, molecule fractions, cooling rates, line emissivities, and equilibrium temperatures are calculated self-consistently. We include dust, cosmic rays, and the interstellar radiation field step-by-step to study their relative impact. These publicly available tables are ideal for hydrodynamical simulations. They can be used stand alone or coupled to a non-equilibrium network for a subset of elements. The release includes a C routine to read in and interpolate the tables, as well as an easy-to-use python graphical user interface to explore the tables.

Far-ultraviolet studies. II - Galactic-latitude dependence of the 1530 A interstellar radiation field

1977 ◽  
Vol 212 ◽  
pp. 707 ◽  
Author(s):  
R. C. Henry ◽  
J. R. Swandic ◽  
S. D. Shulman ◽  
G. Fritz
Keyword(s):  
Radiation Field ◽  
Galactic Latitude ◽  
Latitude Dependence ◽  
Far Ultraviolet

scholarly journals The baryon content of groups and clusters of galaxies in the FABLE simulations

2020 ◽  
Vol 498 (2) ◽  
pp. 2114-2137 ◽  
Author(s):  
Nicholas A Henden ◽  
Ewald Puchwein ◽  
Debora Sijacki
Keyword(s):  
Star Formation ◽  
Stellar Mass ◽  
Outer Radius ◽  
Late Time ◽  
Mass Growth ◽  
Satellite Galaxies ◽  
Hydrodynamical Simulations ◽  
Intracluster Light ◽  
Stellar Masses ◽  
Good Agreement

ABSTRACT We study the gas and stellar mass content of galaxy groups and clusters in the fable suite of cosmological hydrodynamical simulations, including the evolution of their central brightest cluster galaxies (BCGs), satellite galaxies, and intracluster light (ICL). The total gas and stellar mass of fable clusters are in good agreement with observations and show negligible redshift evolution at fixed halo mass for $M_{500} \gtrsim 3 \times 10^{14} \, \mathrm{M}_{\odot }$ at z ≲ 1, in line with recent findings from Sunyaev–Zel’dovich (SZ)-selected cluster samples. Importantly, the simulations predict significant redshift evolution in these quantities in the low-mass ($M_{500} \sim 10^{14} \, \mathrm{M}_{\odot }$) regime, which will be testable with upcoming SZ surveys such as SPT-3G. Whilst the stellar masses of fable BCGs are in reasonable agreement with observations, the total stellar mass in satellite galaxies is lower than observed and the total mass in ICL is somewhat higher. This may be caused by enhanced tidal stripping of satellite galaxies due to their large sizes. BCGs are characterized by moderate stellar mass growth at z &lt; 1 coincident with a late-time development of the ICL. The level of BCG mass growth is in good agreement with recent observations; however, we caution that the inferred growth depends sensitively on the mass definition. We further show that in situ star formation contributes more than half the mass of a BCG over its lifetime, the bulk of which is gained at z &gt; 1 where star formation rates are highest. The stellar mass profiles of the BCG+ICL component are similar to observed profiles out to ∼100 kpc at z ≈ 0 and follow a close to power law shape out to several hundred kpc. We further demonstrate that the inferred size growth of BCGs can be severely biased by the choice of parametric model and the outer radius of the fit.

Mass Loss from Stars

1977 ◽  
Vol 3 (2) ◽  
pp. 96-96
Author(s):  
Donald C. Morton
Keyword(s):  
Mass Loss ◽  
Radiation Field ◽  
Excited States ◽  
Short Wavelength ◽  
Hot Stars ◽  
Short Wavelength Side ◽  
Far Ultraviolet ◽  
Wavelength Side ◽  
Space Observations

The visual spectra of some hot stars, including P Cygni, have emission with associated absorption troughs ˜ 102 km s-1 on the short-wavelength side (Beals 1929, 1951). These P Cygni profiles are easily understood in terms of mass flowing away from the star. Later, rocket observations of the far-ultraviolet resonance lines (Morton 1967) showed that the phenomenon is rather common among hot stars and the velocity shifts could be from 1000 to 3000 km s-1, demonstrating that the mass must be escaping from the star. Resonance lines provide the strongest absorption in the shell where neither the density nor the radiation field is high enough to leave many ions in excited states. Since the ion stages likely to be present around a hot star have their resonance lines shortward of the atmospheric cutoff, space observations are essential in this investigation. Figure 1 shows the P Cygni profile of O VI in ς Pup obtained with Copernicus satellite spectrometer.

scholarly journals The evolution of intracluster medium in stellar clusters

2019 ◽  
Vol 14 (S351) ◽  
pp. 416-419
Author(s):  
W. Chantereau
Keyword(s):  
Globular Clusters ◽  
Galactic Halo ◽  
Radiative Heating ◽  
Stellar Winds ◽  
Intracluster Medium ◽  
Stellar Cluster ◽  
Negligible Amount ◽  
Ram Pressure ◽  
Hydrodynamical Simulations ◽  
Radiative Pressure

AbstractStars in globular clusters lose mass through slow stellar winds that are retained by the stellar cluster and should contribute to build up a non-negligible intracluster medium over time. However, all the observations so far found only a negligible amount of gas in GCs. We propose here to test different mechanisms such as ram-pressure stripping by the motion of the GC in the Galactic halo medium and the inclusion of ionising sources to explain the lack of gas in GCs. We use full 3D hydrodynamical simulations taking into account stellar winds, ionising radiation, radiative heating and radiative pressure. We find that the combined effect of ram-pressure and ionisation are able to explain the negligible amount of gas observed in the core of intermediate-mass and massive GCs.

scholarly journals The Ionisation Equilibrium for Heavy Elements

1968 ◽  
Vol 34 ◽  
pp. 205-208
Author(s):  
D.R. Flower
Keyword(s):  
Radiation Field ◽  
Optical Depth ◽  
Cross Sections ◽  
Ground State ◽  
Spectral Region ◽  
Heavy Elements ◽  
First Approximation ◽  
Initial Work ◽  
Far Ultraviolet ◽  
Better Than

Calculations are being made of the distribution of the ions of heavy elements in planetary nebulae. Initial work has been concentrated on the central or He2+ zone of planetaries. The optical depths of ions of C, N, O, and Ne have been computed using ground state ionisation cross-sections and using approximations which should be substantially better than hydrogenic. A comparison has been made between the combined optical depth of the heavy elements and the optical depth of He+ in the far ultraviolet. The optical depths of the heavy elements in this spectral region may become significant, but a reasonable first approximation to the radiation field may be obtained by neglecting the absorption of all ions except He+. The distribution of the ions of the heavy elements has been calculated on this assumption.

scholarly journals The FRIGG project: From intermediate galactic scales to self-gravitating cores

2018 ◽  
Vol 611 ◽  
pp. A24 ◽  
Author(s):  
Patrick Hennebelle
Keyword(s):  
Initial Conditions ◽  
Critical Mass ◽  
Adaptive Mesh ◽  
Direct Consequence ◽  
Small Scale ◽  
Core Mass ◽  
Numerical Resolution ◽  
The Core ◽  
Prestellar Cores ◽  
Hydrodynamical Simulations

Context. Understanding the detailed structure of the interstellar gas is essential for our knowledge of the star formation process.Aim. The small-scale structure of the interstellar medium (ISM) is a direct consequence of the galactic scales and making the link between the two is essential.Methods. We perform adaptive mesh simulations that aim to bridge the gap between the intermediate galactic scales and the self-gravitating prestellar cores. For this purpose we use stratified supernova regulated ISM magneto-hydrodynamical simulations at the kpc scale to set up the initial conditions. We then zoom, performing a series of concentric uniform refinement and then refining on the Jeans length for the last levels. This allows us to reach a spatial resolution of a few 10−3 pc. The cores are identified using a clump finder and various criteria based on virial analysis. Their most relevant properties are computed and, due to the large number of objects formed in the simulations, reliable statistics are obtained.Results. The cores’ properties show encouraging agreements with observations. The mass spectrum presents a clear powerlaw at high masses with an exponent close to ≃−1.3 and a peak at about 1–2 M⊙. The velocity dispersion and the angular momentum distributions are respectively a few times the local sound speed and a few 10−2 pc km s−1. We also find that the distribution of thermally supercritical cores present a range of magnetic mass-to-flux over critical mass-to-flux ratios, typically between ≃0.3 and 3 indicating that they are significantly magnetized. Investigating the time and spatial dependence of these statistical properties, we conclude that they are not significantly affected by the zooming procedure and that they do not present very large fluctuations. The most severe issue appears to be the dependence on the numerical resolution of the core mass function (CMF). While the core definition process may possibly introduce some biases, the peak tends to shift to smaller values when the resolution improves.Conclusions. Our simulations, which use self-consistently generated initial conditions at the kpc scale, produce a large number of prestellar cores from which reliable statistics can be inferred. Preliminary comparisons with observations show encouraging agreements. In particular the inferred CMFs resemble the ones inferred from recent observations. We stress, however, a possible issue with the peak position shifting with numerical resolution.

scholarly journals Lyα DOMINANCE OF THE CLASSICAL T TAURI FAR-ULTRAVIOLET RADIATION FIELD

2012 ◽  
Vol 756 (1) ◽  
pp. L23 ◽  
Author(s):  
Eric Schindhelm ◽  
Kevin France ◽  
Gregory J. Herczeg ◽  
Edwin Bergin ◽  
Hao Yang ◽  
...  
Keyword(s):  
Ultraviolet Radiation ◽  
Radiation Field ◽  
T Tauri ◽  
Far Ultraviolet

scholarly journals Accretion dynamics and star-disk interaction in NCG 2264

2009 ◽  
Vol 5 (H15) ◽  
pp. 735-735 ◽  
Author(s):  
Silvia H. P. Alencar ◽  
Jérôme Bouvier ◽  
Claude Catala ◽  
Matilde Fernandez ◽  
Jorge Filipe Gameiro ◽  
...  
Keyword(s):  
Magnetic Field ◽  
T Tauri Stars ◽  
Stellar Cluster ◽  
Its Analysis ◽  
T Tauri ◽  
Long Run ◽  
Hydrodynamical Simulations ◽  
First Time

The Corot satellite observed the young stellar cluster NGC 2264 during 23 days in March 2008. This was the first time a group of young accreting stars, classical T Tauri stars (CTTS), were followed ininterruptedly with high photometric accuracy for such a long run. Before the Corot observations, AA Tau (Bouvier et al. 2003, A&A, 409, 169 and Bouvier et al. 2007, A&A, 463, 1017) was one of the few CTTS systems that had been analysed synoptically over several consecutive rotational periods. Its analysis suggested a highly dynamical star-disk interaction mediated by the stellar magnetic field, as predicted by magneto-hydrodynamical simulations of young accreting systems.

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