Article
Astronomy & Astrophysics
Mika Juvela
Summary: By comparing the performance of single modified black body (MBB) model with multi-component models, it is found that multi-component models can significantly reduce systematic errors but at the cost of added statistical noise. The chi(2) values are not a good indicator of the accuracy of the tau estimates due to the dominant role of model errors. The single-MBB model remains a valid alternative when combined with empirical corrections.
ASTRONOMY & ASTROPHYSICS
(2023)
Article
Astronomy & Astrophysics
A. Klepitko, S. Walch, R. Wuensch, D. Seifried, F. Dinnbier, S. Haid
Summary: Radiation is an important factor in the energetics of the interstellar medium, and a novel method called TreeRay/RadPressure has been developed to solve the radiative transfer of diffuse sources. This method allows for the accurate computation of radiative intensities and momentum input by radiation pressure. The application of this method to model massive star formation has shown that radiation heating prevents fragmentation in the vicinity of the newborn star.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2023)
Article
Astronomy & Astrophysics
I-Da Chiang, Hiroyuki Hirashita, Jeremy Chastenet, Eric W. Koch, Adam K. Leroy, Erik Rosolowsky, Karin M. Sandstrom, Amy Sardone, Jiayi Sun, Thomas G. Williams
Summary: We investigated the impact of local environmental factors, particularly dust surface density (sigma(dust)), dust-to-gas ratio (D/G), and interstellar radiation field, on the dust temperature. By analyzing multiwavelength observations in 46 nearby galaxies, we found that the dust temperature is strongly correlated with the surface density of star formation rate (sigma(SFR)), which is indicative of radiation from young stars. Additionally, the dust temperature decreases as D/G increases, suggesting stronger dust shielding at higher D/G values. Our findings are consistent with the predictions of our proposed analytical model.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2023)
Article
Astronomy & Astrophysics
Jifeng Xia, Ningyu Tang, Qijun Zhi, Sihan Jiao, Jinjin Xie, Gary A. Fuller, Paul F. Goldsmith, Di Li
Summary: The distribution of UV radiation field provides important constraints on the physical environments of molecular clouds. By analyzing the data from the Herschel Gould Belt Survey, we obtained the spatial distribution of the radiation field in molecular cloud regions within the Gould Belt. We found a linear correlation between star formation rate and UV radiation intensity.
RESEARCH IN ASTRONOMY AND ASTROPHYSICS
(2022)
Article
Astronomy & Astrophysics
Michael Y. Grudic, David Guszejnov, Stella S. R. Offner, Anna L. Rosen, Aman N. Raju, Claude-Andre Faucher-Giguere, Philip F. Hopkins
Summary: This study analyzes the evolution of the first giant molecular cloud through simulation, focusing on star formation and feedback mechanisms. Findings indicate that protostellar jets, radiation, and winds contribute to cloud dispersal, while supernovae have a limited impact on star formation. The simulation closely resembles reality, but further comparisons with synthetic observations are necessary to constrain theoretical uncertainties.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2022)
Article
Astronomy & Astrophysics
Vineet Rawat, M. R. Samal, D. L. Walker, A. Zavagno, A. Tej, G. Marton, D. K. Ojha, Davide Elia, W. P. Chen, J. Jose, C. Eswaraiah
Summary: Studying the properties of clouds in the early stages of their evolution provides an opportunity to test cluster formation processes. By analyzing the CO, Herschel, and UKIDSS observations of cloud G148.24+00.41, we find that it is a high mass, low dust temperature cloud with a nearly circular shape. Comparing its properties with nearby molecular clouds, we determine that it is similar to the Orion-A molecular cloud in terms of mass, size, and dense gas fraction. Our analysis also suggests that the cloud has the potential to form a cluster in the mass range of 2000-3000 M-circle dot through hierarchical collapse and assembly of gas and stars.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2023)
Article
Astronomy & Astrophysics
M. Juvela, E. Mannfors
Summary: The properties of filamentary structures in star-forming interstellar clouds were compared using mid-infrared absorption and far-infrared dust emission in the Orion Molecular Cloud 3 (OMC-3). The results show that the widths of the OMC-3 filaments were consistent between the mid-infrared and far-infrared analyses. However, there were potential sources of systematic error, particularly at high column densities and in weak radiation fields.
ASTRONOMY & ASTROPHYSICS
(2023)
Article
Astronomy & Astrophysics
R. Siebenmorgen, J. Smoker, J. Krelowski, Karl Gordon, Rolf Chini
Summary: By merging a sample of 820 reddening curves of stars, the highest-quality Milky Way reddening curve sample has been obtained, confirming previous estimates. A future paper in this series will use the current sample of precise reddening curves and combine them with polarization data to study the properties of dark dust.
ASTRONOMY & ASTROPHYSICS
(2023)
Article
Astronomy & Astrophysics
R. Kannan, M. Vogelsberger, F. Marinacci, L. Sales, P. Torrey, L. Hernquist
Summary: Stellar feedback-driven winds play a crucial role in the galactic ecosystem by regulating star formation and enriching the circumgalactic medium with metals and dust. The amount of ejected dust depends on the sites from where they are launched, with dustier galaxies launching more dust-enriched outflows. Cold and dense gas outflows are significantly more dust enriched compared to hot and tenuous material, providing new insights into the dynamics, structure, and composition of galactic winds.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2021)
Article
Astronomy & Astrophysics
Sajay Sunny Mathew, Christoph Federrath
Summary: The study demonstrates that various factors in star cluster formation, including protostellar outflows, affect the star formation rate, mass distribution, and initial mass function. The turbulence-based model and observational IMF agree well in the high-mass and low-mass regime, but do not predict any brown dwarfs.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2021)
Article
Astronomy & Astrophysics
Shyam H. Menon, Christoph Federrath, Mark R. Krumholz
Summary: We present 3D radiation-hydrodynamical simulations of star cluster formation and evolution in self-gravitating clouds that are optically thick to infrared photons. Using a novel RHD algorithm - VETTAM, we investigate the impact of IR radiation pressure on the star formation efficiency and the potential for driving dusty winds. Our results suggest that the commonly adopted simplifications of IR dust opacities lead to overestimation of the radiation force and that realistic opacities that consider the microphysics of dust show a very mild effect of IR radiation pressure on star formation.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2022)
Article
Astronomy & Astrophysics
Anton A. Smirnov, Sergey S. Savchenko, Denis M. Poliakov, Alexander A. Marchuk, Aleksandr V. Mosenkov, Vladimir B. Il'in, George A. Gontcharov, Javier Roman, Jonah Seguine
Summary: Using machine learning and neural networks, we successfully isolated galactic cirrus filaments from SDSS Stripe 82 data. Our study found that only filaments brighter than 26 mag arcsec(-2) in the SDSS r band can be identified based on their distinctive colors in the optical bands. We also discovered a significant impact of data processing on color estimation, including flat-fielding, masking of bright stars, and sky subtraction. By analyzing the color distribution of filaments with mock simulations, we concluded that most filaments fall within the ranges of 0.55 <= g - r <= 0.73 and 0.01 <= r - i <= 0.33. Our work provides a useful framework for analyzing various types of low surface brightness features in deep optical surveys and includes a catalog of dust filaments for practical purposes.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2023)
Article
Astronomy & Astrophysics
Alexander A. Marchuk, Anton A. Smirnov, Aleksandr Mosenkov, Vladimir B. Il'in, George A. Gontcharov, Sergey S. Savchenko, Javier Roman
Summary: This study measures the fractal dimension of cirrus clouds using optical data for the first time, finding that the averaged fractal dimension in optical data is significantly larger than in IR data. The discrepancy in fractal dimensions may be explained by differences in angular resolution and physical properties of the clouds, with further simulations needed for confirmation.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2021)
Article
Astronomy & Astrophysics
Nirmit Sakre, Asao Habe, Alex R. Pettitt, Takashi Okamoto, Rei Enokiya, Yasuo Fukui, Takashi Hosokawa
Summary: In this study, the effects of magnetic fields on the formation of massive, self-gravitationally bound cores (MBCs) in high-speed cloud-cloud collisions (CCCs) are investigated through magnetohydrodynamic simulations. The results show that magnetic fields hinder the growth of cores, especially in short-duration collisions. This two-fold effect of magnetic fields on the MBC formation in CCCs results in a maximum collision speed for the formation of massive stars.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2023)
Article
Astronomy & Astrophysics
Michael Y. Grudic, David Guszejnov, Philip F. Hopkins, Stella S. R. Offner, Claude-Andre Faucher-Giguere
Summary: STARFORGE is a new numerical framework for 3D radiation magnetohydrodynamic simulations of star formation, incorporating various stellar feedback mechanisms. It utilizes advanced algorithms and methods to accurately model the formation, evolution, and dynamics of individual stars in massive giant molecular clouds. The model has been shown to scale up to massive GMCs on current supercomputers while accurately predicting the stellar range of the IMF.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2021)