scholarly journals 3D dust radiative transfer simulations in the inhomogeneous interstellar medium

2006 ◽  
Vol 2 (S237) ◽  
pp. 490-490
Author(s):  
E. Vidal Perez ◽  
M. Baes
Keyword(s):  
Temperature Distribution ◽  
Radiative Transfer ◽  
Interstellar Medium ◽  
Dust Temperature ◽  
T Tauri ◽  
Dust Distribution ◽  
Initial Results

AbstractThe study of dusty discs is an important topic in astrophysics, as they seem to be abundant around different objects and are related to different phenomena. In this poster we present 3D radiative transfer simulations of T Tauri type discs with an inhomogeneous dust distribution to investigate the effect of a clumpy medium on the dust temperature distribution. Our initial results indicate that the structure of the dust temperature distribution is rather insensitive to the structure of the ISM, but nevertheless we find a clear and systematic dependence on the parameters describing the structure of the clumpiness of the dust medium.

scholarly journals Simulating the interstellar medium of galaxies with radiative transfer, non-equilibrium thermochemistry, and dust

2020 ◽  
Vol 499 (4) ◽  
pp. 5732-5748 ◽  
Author(s):  
Rahul Kannan ◽  
Federico Marinacci ◽  
Mark Vogelsberger ◽  
Laura V Sales ◽  
Paul Torrey ◽  
...  
Keyword(s):  
Interstellar Medium ◽  
Galaxy Formation ◽  
State Of The Art ◽  
Complex Function ◽  
Ionization State ◽  
Radiation Fields ◽  
Stellar Feedback ◽  
Wide Range ◽  
Dust Distribution ◽  
Non Equilibrium

ABSTRACT We present a novel framework to self-consistently model the effects of radiation fields, dust physics, and molecular chemistry (H2) in the interstellar medium (ISM) of galaxies. The model combines a state-of-the-art radiation hydrodynamics module with a H  and He  non-equilibrium thermochemistry module that accounts for H2 coupled to an empirical dust formation and destruction model, all integrated into the new stellar feedback framework SMUGGLE. We test this model on high-resolution isolated Milky-Way (MW) simulations. We show that the effect of radiation feedback on galactic star formation rates is quite modest in low gas surface density galaxies like the MW. The multiphase structure of the ISM, however, is highly dependent on the strength of the interstellar radiation field. We are also able to predict the distribution of H2, that allow us to match the molecular Kennicutt–Schmidt (KS) relation, without calibrating for it. We show that the dust distribution is a complex function of density, temperature, and ionization state of the gas. Our model is also able to match the observed dust temperature distribution in the ISM. Our state-of-the-art model is well-suited for performing next-generation cosmological galaxy formation simulations, which will be able to predict a wide range of resolved (∼10 pc) properties of galaxies.

scholarly journals Lymanαline and continuum radiative transfer in a clumpy interstellar medium

2014 ◽  
Vol 562 ◽  
pp. A52 ◽  
Author(s):  
F. Duval ◽  
D. Schaerer ◽  
G. Östlin ◽  
P. Laursen
Keyword(s):  
Radiative Transfer ◽  
Interstellar Medium

Initial Results of Monitoring the Temperature on the Facade of Office Building

2019 ◽  
Vol 887 ◽  
pp. 411-418
Author(s):  
Peter Juras ◽  
Radoslav Ponechal ◽  
Daniela Štaffenová
Keyword(s):  
Temperature Distribution ◽  
Air Temperature ◽  
Full Scale ◽  
Office Building ◽  
Wind Flow ◽  
Climate Conditions ◽  
Outdoor Climate ◽  
Measurement Units ◽  
Weather Stations ◽  
Initial Results

This paper deals with creating of the unique measurement units on the building façade, which enable the possibility to conduct a full-scale measurement of the outdoor climate parameters around the building. The façade of the Research center building, which is a part of University of Zilina campus, is equipped with 36 weather stations to measure the outdoor climate conditions and impact of the building on the approaching wind flow, air temperature distribution, solar radiance impact on the façade etc.In this article, the change of temperatures within the time and place on the facade (sides, position, time), is monitored. This takes into account the surroundings of the building and the temperature on the façade and comparison to the measured “basic” air temperature.

scholarly journals The 12C/13C Ratio in Interstellar Dark Clouds

1980 ◽  
Vol 87 ◽  
pp. 411-416
Author(s):  
W.H. Mccutcheon ◽  
R. L. Dickman ◽  
W.L.H. Shuter ◽  
R. S. Roger
Keyword(s):  
Radiative Transfer ◽  
Interstellar Medium ◽  
Stellar Evolution ◽  
Transfer Problem ◽  
Abundance Ratio ◽  
Radiative Transfer Problem ◽  
Dark Clouds ◽  
Non Equilibrium

Since 13C is believed to be produced by non-equilibrium CNO processing in stellar evolution (Truran 1977), measurements of the carbon ratio Rc ≡ [12C] / [13C] in the interstellar medium may provide important information on nucleo-synthesis. Commonly, the ratio (N13/N18)LTE ≡ [13CO/C18O]LTE is measured and from this RLTE ≡ [12CO/13CO]LTE is deduced and these values are often identified with Rc. However, this line of reasoning can be misleading for two reasons (Dickman et al. 1979):(1) The difficulty of determining accurate column densities, [13C16O] and [12C18O], because of the complexity of the radiative transfer problem;(2) The possible role of fractionation, whereby RCO ≡ [12CO] / [13CO] does not necessarily reflect the initial atomic abundance ratio RC (Watson et al. 1976, Langer 1977, Liszt 1978).

scholarly journals Adaptable Radiative Transfer Innovations for Submillimeter Telescopes (ARTIST)

2010 ◽  
Vol 6 (S270) ◽  
pp. 451-454 ◽  
Author(s):  
Marco Padovani ◽  
Jes K. Jørgensen ◽  
Frank Bertoldi ◽  
Christian Brinch ◽  
Pau Frau ◽  
...  
Keyword(s):  
Radiative Transfer ◽  
Interstellar Medium ◽  
Line Emission ◽  
Generation Model ◽  
Next Generation ◽  
Material Cycles

AbstractSubmillimeter observations are a key for answering many of the big questions in modern-day astrophysics, such as how stars and planets form, how galaxies evolve, and how material cycles through stars and the interstellar medium. With the upcoming large submillimeter facilities ALMA and Herschel a new window will open to study these questions. ARTIST is a project funded in context of the European ASTRONET program with the aim of developing a next generation model suite for comprehensive multi-dimensional radiative transfer calculations of the dust and line emission, as well as their polarization, to help interpret observations with these groundbreaking facilities.

A Numerical Model to Analyze the Thermal Behavior of a Propellant Increment

2015 ◽  
Author(s):  
K. Blecker ◽  
H. Hadim
Keyword(s):  
Temperature Distribution ◽  
Numerical Model ◽  
Thermal Behavior ◽  
Pressure Profile ◽  
Bulk Temperature ◽  
Safety Hazard ◽  
Thermal Environments ◽  
Environment Temperature ◽  
Burn Rate ◽  
Initial Results

The purpose of this study is to develop a numerical model of the thermal behavior of a propellant increment exposed to a variety of thermal environments and packaging conditions and predict the temperature distribution throughout the increment. The temperature distribution and bulk temperature of the propellant within the increment directly influence the burn rate and resulting pressure profile. The burn rate and pressure profile directly impact the range and stability of the munition which can result in a safety hazard if not properly accounted for. This study has two parts; first a numerical model is developed and second an experiment is designed and carried out to validate the numerical model. The experiment involves instrumenting a propellant increment with a series of thermocouples and heating it in a controlled laboratory environment. Temperature data is collected with a dedicated data collector and retained for analysis and validation of the numerical model. The numerical model accounts for variable thermal solar loading, various packaging configurations, and orientation. Initial results indicate that while there are points in the interior of the increment that come within 10 percent of the actual bulk temperature of the entire increment, the surface of the increment is not a good basis for prediction of the bulk temperature or temperature distribution within the increment. Additional analysis must be conducted to provide a viable estimate of the temperature distribution and bulk temperature of the increment based on the surface temperature in conjunction with knowledge of the exposure conditions.

scholarly journals Organic molecules in the protoplanetary disk of DG Tauri revealed by ALMA

2019 ◽  
Vol 623 ◽  
pp. L6 ◽  
Author(s):  
L. Podio ◽  
F. Bacciotti ◽  
D. Fedele ◽  
C. Favre ◽  
C. Codella ◽  
...  
Keyword(s):  
Column Density ◽  
Protoplanetary Disks ◽  
Temperature Inversion ◽  
Abundance Ratio ◽  
Chemical Compositions ◽  
Outer Disk ◽  
T Tauri ◽  
Dust Distribution ◽  
Disk Height ◽  
Co Emission

Context. Planets form in protoplanetary disks and inherit their chemical compositions. Aims. It is thus crucial to map the distribution and investigate the formation of simple organics, such as formaldehyde and methanol, in protoplanetary disks. Methods. We analyze ALMA observations of the nearby disk-jet system around the T Tauri star DG Tau in the o − H2CO 31, 2 − 21, 1 and CH3OH 3−2, 2 − 4−1, 4 E, 50, 5 − 40, 4 A transitions at an unprecedented resolution of $ {\sim}0{{\overset{\prime\prime}{.}}}{15} $, i.e., ∼18 au at a distance of 121 pc. Results. The H2CO emission originates from a rotating ring extending from ∼40 au with a peak at ∼62 au, i.e., at the edge of the 1.3 mm dust continuum. CH3OH emission is not detected down to an rms of 3 mJy beam−1 in the 0.162 km s−1 channel. Assuming an ortho-to-para ratio of 1.8−2.8 the ring- and disk-height-averaged H2CO column density is ∼0.3−4 × 1014 cm−2, while that of CH3OH is < 0.04−0.7 × 1014 cm−2. In the inner 40 au no o − H2CO emission is detected with an upper limit on its beam-averaged column density of ∼0.5−6 × 1013 cm−2. Conclusions. The H2CO ring in the disk of DG Tau is located beyond the CO iceline (RCO ∼ 30 au). This suggests that the H2CO abundance is enhanced in the outer disk due to formation on grain surfaces by the hydrogenation of CO ice. The emission peak at the edge of the mm dust continuum may be due to enhanced desorption of H2CO in the gas phase caused by increased UV penetration and/or temperature inversion. The CH3OH/H2CO abundance ratio is < 1, in agreement with disk chemistry models. The inner edge of the H2CO ring coincides with the radius where the polarization of the dust continuum changes orientation, hinting at a tight link between the H2CO chemistry and the dust properties in the outer disk and at the possible presence of substructures in the dust distribution.

A new method for analyzing IRAS data to determine the dust temperature distribution

1991 ◽  
Vol 371 ◽  
pp. L81 ◽  
Author(s):  
Taoling Xie ◽  
Paul F. Goldsmith ◽  
Weimin Zhou
Keyword(s):  
Temperature Distribution ◽  
New Method ◽  
Dust Temperature

TheSPITZERc2d Survey of Weak‐Line T Tauri Stars. I. Initial Results

2006 ◽  
Vol 645 (2) ◽  
pp. 1283-1296 ◽  
Author(s):  
Deborah L. Padgett ◽  
Lucas Cieza ◽  
Karl R. Stapelfeldt ◽  
Neal J. Evans, II ◽  
David Koerner ◽  
...  
Keyword(s):  
T Tauri Stars ◽  
Weak Line ◽  
T Tauri ◽  
Initial Results

Observational Evidence on the Interaction of Orion Population Stars and the Interstellar Medium

1977 ◽  
Vol 42 ◽  
pp. 25-37 ◽  
Author(s):  
G. Grasdalen
Keyword(s):  
Interstellar Medium ◽  
Long Range ◽  
Direct Evidence ◽  
Observational Evidence ◽  
Young Stars ◽  
Strong Interactions ◽  
Range Interaction ◽  
Circumstellar Material ◽  
T Tauri ◽  
Long Range Interaction

The Orion population stars are those stars which have only recently formed. It is generally accepted that these stars arose as condensations in the interstellar medium. It follows that they should show strong interactions with that material. In only one case, the nebula near T Tauri (Schwartz 1974) do we have any direct evidence for the interaction between these stars and the interstellar medium. Presumably this is because the typical interactions take place on much larger or much shorter distance scales. The long range interaction of young stars with their environment is discussed in Section II.It is also generally agreed that Orion population stars are still enshrouded in circumstellar material. There are important questions that have yet to be answered about that material before we can begin to discuss the details of any interaction between these stars and their surroundings. These difficulties are discussed in Section III.Finally, I have chosen four topics to discuss in somewhat more detail. My aim has been either to urge caution in accepting current interpretations or to put caution aside and suggest new possibilities.

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