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21 results on '"Klessen, Ralf S."'

1. Do spiral arms enhance star formation efficiency?

Author

Querejeta, Miguel, primary, Leroy, Adam K., additional, Meidt, Sharon E., additional, Schinnerer, Eva, additional, Belfiore, Francesco, additional, Emsellem, Eric, additional, Klessen, Ralf S., additional, Sun, Jiayi, additional, Sormani, Mattia, additional, Beslic, Ivana, additional, Cao, Yixian, additional, Chevance, Mélanie, additional, Colombo, Dario, additional, Dale, Daniel A., additional, García-Burillo, Santiago, additional, Glover, Simon C.O., additional, Grasha, Kathryn, additional, Groves, Brent, additional, Koch, Eric W., additional, Neumann, Lukas, additional, Pan, Hsi-An, additional, Pessa, Ismael, additional, Pety, Jérôme, additional, Pinna, Francesca, additional, Ramambason, Lise, additional, Razza, Alessandro, additional, Romanelli, Andrea, additional, Rosolowsky, Erik, additional, Ruiz-García, Marina, additional, Sánchez-Blázquez, Patricia, additional, Smith, Rowan, additional, Stuber, Sophia, additional, Ubeda, Leonardo, additional, Usero, Antonio, additional, and Williams, Thomas G., additional

Published
2024
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2. Simulating nearby disc galaxies on the main star formationsequence. I. Bar formation and the building of the central gas reservoir

Author

Verwilghen, Pierrick, primary, Emsellem, Eric, additional, Renaud, Florent, additional, Valentini, Milena, additional, Sun, Jiayi, additional, Jeffreson, Sarah, additional, Klessen, Ralf S., additional, Mattia Sormani, C., additional, Ashley Barnes, T., additional, Dolag, Klaus, additional, Grasha, Kathryn, additional, Liang, Fu-Heng, additional, Meidt, Sharon, additional, Neumann, Justus, additional, Querejeta, Miguel, additional, Schinnerer, Eva, additional, and Thomas Williams, G., additional

Published
2024
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3. Cloud properties across spatial scales in simulations of the interstellar medium

Author

Colman, Tine, primary, Brucy, Noé, additional, Girichidis, Philipp, additional, Glover, Simon C.O., additional, Benedettini, Milena, additional, Soler, Juan D., additional, Tress, Robin G., additional, Traficante, Alessio, additional, Hennebelle, Patrick, additional, Klessen, Ralf S., additional, Molinari, Sergio, additional, and Miville-Deschenes, Marc-Antoine, additional

Published
2024
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5. Simulating nearby disc galaxies on the main star formation sequence: I. Bar formation and the building of the central gas reservoir.

Author

Verwilghen, Pierrick, Emsellem, Eric, Renaud, Florent, Valentini, Milena, Sun, Jiayi, Jeffreson, Sarah, Klessen, Ralf S., Sormani, Mattia C., Barnes, Ashley T., Dolag, Klaus, Grasha, Kathryn, Liang, Fu-Heng, Meidt, Sharon, Neumann, Justus, Querejeta, Miguel, Schinnerer, Eva, and Williams, Thomas G.

Subjects
INTERSTELLAR medium, GALACTIC evolution, MAIN sequence (Astronomy), DISK galaxies, STELLAR mass
Abstract

Past studies have long emphasised the key role played by galactic stellar bars in the context of disc secular evolution, via the redistribution of gas and stars, the triggering of star formation, and the formation of prominent structures such as rings and central mass concentrations. However, the exact physical processes acting on those structures, as well as the timescales associated with the building and consumption of central gas reservoirs are still not well understood. We are building a suite of hydro-dynamical RAMSES simulations of isolated, low-redshift galaxies that mimic the properties of the PHANGS sample. The initial conditions of the models reproduce the observed stellar mass, disc scale length, or gas fraction, and this paper presents a first subset of these models. Most of our simulated galaxies develop a prominent bar structure, which itself triggers central gas fuelling and the building of an over-density with a typical scale of 100−1000 pc. We confirm that if the host galaxy features an ellipsoidal component, the formation of the bar and gas fuelling are delayed. We show that most of our simulations follow a common time evolution, when accounting for mass scaling and the bar formation time. In our simulations, the stellar mass of 1010 M⊙ seems to mark a change in the phases describing the time evolution of the bar and its impact on the interstellar medium. In massive discs (M⋆ ≥ 1010 M⊙), we observe the formation of a central gas reservoir with star formation mostly occurring within a restricted starburst region, leading to a gas depletion phase. Lower-mass systems (M⋆ < 1010 M⊙) do not exhibit such a depletion phase, and show a more homogeneous spread of star-forming regions along the bar structure, and do not appear to host inner bar-driven discs or rings. Our results seem to be supported by observations, and we briefly discuss how this new suite of simulations can help our understanding of the secular evolution of main sequence disc galaxies. [ABSTRACT FROM AUTHOR]

Published
2024
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6. A sensitive, high-resolution, wide-field IRAM NOEMA CO(1–0) survey of the very nearby spiral galaxy IC 342

Author

Querejeta, Miguel, primary, Pety, Jérôme, additional, Schruba, Andreas, additional, Leroy, Adam K., additional, Herrera, Cinthya N., additional, Chiang, I-Da, additional, Meidt, Sharon E., additional, Rosolowsky, Erik, additional, Schinnerer, Eva, additional, Schuster, Karl, additional, Sun, Jiayi, additional, Herrmann, Kimberly A., additional, Barnes, Ashley T., additional, Bešlić, Ivana, additional, Bigiel, Frank, additional, Cao, Yixian, additional, Chevance, Mélanie, additional, Eibensteiner, Cosima, additional, Emsellem, Eric, additional, Faesi, Christopher M., additional, Hughes, Annie, additional, Kim, Jaeyeon, additional, Klessen, Ralf S., additional, Kreckel, Kathryn, additional, Diederik Kruijssen, J. M., additional, Liu, Daizhong, additional, Neumayer, Nadine, additional, Pan, Hsi-An, additional, Saito, Toshiki, additional, Sandstrom, Karin, additional, Teng, Yu-Hsuan, additional, Usero, Antonio, additional, Williams, Thomas G., additional, and Zakardjian, Antoine, additional

Published
2023
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7. Heavy black hole seed formation in high-z atomic cooling halos.

Author

Prole, Lewis R., Regan, John A., Glover, Simon C. O., Klessen, Ralf S., Priestley, Felix D., and Clark, Paul C.

Subjects
BLACK holes, PROTOSTARS, STELLAR mass, ATOMIC mass, STAR formation, SUPERMASSIVE black holes
Abstract

Context. Halos with masses in excess of the atomic limit are believed to be ideal environments in which to form heavy black hole seeds with masses above 103 M⊙. In cases where the H2 fraction is suppressed, this is expected to lead to reduced fragmentation of the gas and the generation of a top-heavy initial mass function. In extreme cases this can result in the formation of massive black hole seeds. Resolving the initial fragmentation scale and the resulting protostellar masses has, until now, not been robustly tested. Aims. We run zoom-in simulations of atomically cooled halos in which the formation of H2 is suppressed to assess whether they can truly resist fragmentation at high densities and tilt the initial mass function towards a more top-heavy form and the formation of massive black hole seeds. Methods. Cosmological simulations were performed with the moving mesh code AREPO, using a primordial chemistry network until z ∼ 11. Three haloes with masses in excess of the atomic cooling mass were then selected for detailed examination via zoom-ins. A series of zoom-in simulations, with varying levels of maximum spatial resolution, captured the resulting fragmentation and formation of metal-free stars using the sink particle technique. The highest resolution simulations resolved densities up to 10−6 g cm−3 (1018 cm−3) and captured a further 100 yr of fragmentation behaviour at the centre of the halo. Lower resolution simulations were then used to model the future accretion behaviour of the sinks over longer timescales. Results. Our simulations show intense fragmentation in the central region of the halos, leading to a large number of near-solar mass protostars. Even in the presence of a super-critical Lyman-Werner radiation field (JLW > 105J21), H2 continues to form within the inner ∼2000 au of the halo. Despite the increased fragmentation, the halos produce a protostellar mass spectrum that peaks at higher masses relative to standard Population III star-forming halos. The most massive protostars have accretion rates of 10−3–10−1 M⊙ yr−1 after the first 100 years of evolution, while the total mass of the central region grows at 1 M⊙ yr−1. Lower resolution zoom-ins show that the total mass of the system continues to accrete at ∼1 M⊙ yr−1 for at least 104 yr, although how this mass is distributed amongst the rapidly growing number of protostars is unclear. However, assuming that a fraction of stars can continue to accrete rapidly, the formation of a sub-population of stars with masses in excess of 103 M⊙ is likely in these halos. In the most optimistic case, we predict the formation of heavy black hole seeds with masses in excess of 104 M⊙, assuming an accretion behaviour in line with expectations from super-competitive accretion and/or frequent mergers with secondary protostars. [ABSTRACT FROM AUTHOR]

Published
2024
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8. Calibrating mid-infrared emission as a tracer of obscured star formation on H II-region scales in the era of JWST

Author

Belfiore, Francesco, primary, Leroy, Adam K., additional, Williams, Thomas G., additional, Barnes, Ashley T., additional, Bigiel, Frank, additional, Boquien, Médéric, additional, Cao, Yixian, additional, Chastenet, Jérémy, additional, Congiu, Enrico, additional, Dale, Daniel A., additional, Egorov, Oleg V., additional, Eibensteiner, Cosima, additional, Emsellem, Eric, additional, Glover, Simon C. O., additional, Groves, Brent, additional, Hassani, Hamid, additional, Klessen, Ralf S., additional, Kreckel, Kathryn, additional, Neumann, Lukas, additional, Neumann, Justus, additional, Querejeta, Miguel, additional, Rosolowsky, Erik, additional, Sanchez-Blazquez, Patricia, additional, Sandstrom, Karin, additional, Schinnerer, Eva, additional, Sun, Jiayi, additional, Sutter, Jessica, additional, and Watkins, Elizabeth J., additional

Published
2023
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9. The impact of Hii regions on giant molecular cloud properties in nearby galaxies sampled by PHANGS ALMA and MUSE

Author

Zakardjian, Antoine, primary, Pety, Jérôme, additional, Herrera, Cinthya N., additional, Hughes, Annie, additional, Oakes, Elias, additional, Kreckel, Kathryn, additional, Faesi, Chris, additional, Glover, Simon C. O., additional, Groves, Brent, additional, Klessen, Ralf S., additional, Meidt, Sharon, additional, Barnes, Ashley, additional, Belfiore, Francesco, additional, Bešlić, Ivana, additional, Bigiel, Frank, additional, Blanc, Guillermo A., additional, Chevance, Mélanie, additional, Dale, Daniel A., additional, den Brok, Jakob, additional, Eibensteiner, Cosima, additional, Emsellem, Eric, additional, García-Rodríguez, Axel, additional, Grasha, Kathryn, additional, Koch, Eric W., additional, Leroy, Adam K., additional, Liu, Daizhong, additional, Mc Elroy, Rebecca, additional, Neumann, Lukas, additional, Pan, Hsi-An, additional, Querejeta, Miguel, additional, Razza, Alessandro, additional, Rosolowsky, Erik, additional, Saito, Toshiki, additional, Santoro, Francesco, additional, Schinnerer, Eva, additional, Sun, Jiayi, additional, Usero, Antonio, additional, Watkins, Elizabeth J., additional, and Williams, Thomas, additional

Published
2023
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11. Invertible Neural Networks in Astrophysics

Author

Klessen Ralf S.

Subjects
Physics, QC1-999
Abstract

Modern machine learning techniques have become indispensable in many fields of astronomy and astrophysics. Here we introduce a specific class of methods, invertible neural networks, and discuss two specific applications, the prediction of stellar parameters from photometric observations and the study of stellar feedback processes from on emission lines.

Published
2022
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12. C I and CO in nearby spiral galaxies

Author

Liu, Daizhong, primary, Schinnerer, Eva, additional, Saito, Toshiki, additional, Rosolowsky, Erik, additional, Leroy, Adam, additional, Usero, Antonio, additional, Sandstrom, Karin, additional, Klessen, Ralf S., additional, Glover, Simon C. O., additional, Ao, Yiping, additional, Bešlić, Ivana, additional, Bigiel, Frank, additional, Cao, Yixian, additional, Chastenet, Jérémy, additional, Chevance, Mélanie, additional, Dale, Daniel A., additional, Gao, Yu, additional, Hughes, Annie, additional, Kreckel, Kathryn, additional, Diederik Kruijssen, J. M., additional, Pan, Hsi-An, additional, Pety, Jérôme, additional, Salak, Dragan, additional, Santoro, Francesco, additional, Schruba, Andreas, additional, Sun, Jiayi, additional, Teng, Yu-Hsuan, additional, and Williams, Thomas, additional

Published
2023
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13. Calibration of hybrid resolved star formation rate recipes based on PHANGS–MUSE Hα and Hβ maps

Author

Belfiore, Francesco, primary, Leroy, Adam K., additional, Sun, Jiayi, additional, Barnes, Ashley T., additional, Boquien, Médéric, additional, Cao, Yixian, additional, Congiu, Enrico, additional, Dale, Daniel A., additional, Egorov, Oleg V., additional, Eibensteiner, Cosima, additional, Glover, Simon C. O., additional, Grasha, Kathryn, additional, Groves, Brent, additional, Klessen, Ralf S., additional, Kreckel, Kathryn, additional, Neumann, Lukas, additional, Querejeta, Miguel, additional, Sanchez-Blazquez, Patricia, additional, Schinnerer, Eva, additional, and Williams, Thomas G., additional

Published
2023
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14. Influence of magnetic field and stellar radiative feedback on the collapse and the stellar mass spectrum of a massive star-forming clump

Author

Hennebelle, Patrick, primary, Lebreuilly, Ugo, additional, Colman, Tine, additional, Elia, Davide, additional, Fuller, Gary, additional, Leurini, Silvia, additional, Nony, Thomas, additional, Schisano, Eugenio, additional, Soler, Juan D., additional, Traficante, Alessio, additional, Klessen, Ralf S., additional, Molinari, Sergio, additional, and Testi, Leonardo, additional

Published
2022
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15. A physically motivated “charge-exchange method” for measuring electron temperatures within H ii regions

Author

Kreckel, Kathryn, primary, Egorov, Oleg V., additional, Belfiore, Francesco, additional, Groves, Brent, additional, Glover, Simon C. O., additional, Klessen, Ralf S., additional, Sandstrom, Karin, additional, Bigiel, Frank, additional, Dale, Daniel A., additional, Grasha, Kathryn, additional, Scheuermann, Fabian, additional, Schinnerer, Eva, additional, and Williams, Thomas G., additional

Published
2022
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16. A CO isotopologue Line Atlas within the Whirlpool galaxy Survey (CLAWS)

Author

den Brok, Jakob S., primary, Bigiel, Frank, additional, Sliwa, Kazimierz, additional, Saito, Toshiki, additional, Usero, Antonio, additional, Schinnerer, Eva, additional, Leroy, Adam K., additional, Jiménez-Donaire, María J., additional, Rosolowsky, Erik, additional, Barnes, Ashley T., additional, Puschnig, Johannes, additional, Pety, Jérôme, additional, Schruba, Andreas, additional, Bešlić, Ivana, additional, Cao, Yixian, additional, Eibensteiner, Cosima, additional, Glover, Simon C. O., additional, Klessen, Ralf S., additional, Diederik Kruijssen, J. M., additional, Meidt, Sharon E., additional, Neumann, Lukas, additional, Tomičić, Neven, additional, Pan, Hsi-An, additional, Querejeta, Miguel, additional, Watkins, Elizabeth, additional, Williams, Thomas G., additional, and Wilner, David, additional

Published
2022
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17. Ci and CO in nearby spiral galaxies: I. Line ratio and abundance variations at ~200 pc scales.

Author

Daizhong Liu, Schinnerer, Eva, Toshiki Saito, Rosolowsky, Erik, Leroy, Adam, Usero, Antonio, Sandstrom, Karin, Klessen, Ralf S., Glover, Simon C. O., Yiping Ao, Bešlić, Ivana, Bigiel, Frank, Yixian Cao, Chastenet, Jérémy, Chevance, Mélanie, Dale, Daniel A., Yu Gao, Hughes, Annie, Kreckel, Kathryn, and Kruijssen, J. M. Diederik

Subjects
MOLECULAR clouds, INTERSTELLAR medium, ACTIVE galactic nuclei, SPIRAL galaxies, RADIATIVE transfer, SPATIAL resolution
Abstract

We present new neutral atomic carbon [C i] (3P1! 3P0) mapping observations within the inner ~7 kpc and ~4 kpc of the disks of NGC3627 and NGC4321 at a spatial resolution of 190 pc and 270 pc, respectively, using the Atacama Large Millimeter/Submillimeter Array (ALMA) Atacama Compact Array (ACA). We combine these with the CO(21) data from PHANGS-ALMA, and literature [C i] and CO data for two other starburst and/or active galactic nucleus (AGN) galaxies (NGC 1808, NGC7469) with the aim of studying: (a) the spatial distributions of C i and CO emission; (b) the observed line ratio RCi=CO = I[Ci](10)=ICO(21) as a function of various galactic properties; and (c) the abundance ratio of [C i/CO]. We find excellent spatial correspondence between C i and CO emission and nearly uniform RCi=CO ~ 0:1 across the majority of the star-forming disks of NGC3627 and NGC4321. However, RCi=CO strongly varies from ~0:05 at the center of NGC4321 to >0:20:5 in NGC1808's starbursting center and NGC7469's center with an X-ray-luminous AGN. Meanwhile, RCi=CO does not obviously vary with hUi, which is in line with predictions from photodissociation-dominated region (PDR) models. We also find a mildly decreasing RCi=CO value with an increasing metallicity over 0:70:85 Z, which is consistent with the literature. Assuming various typical interstellar medium (ISM) conditions representing giant molecular clouds, active star-forming regions, and strong starbursting environments, we calculated the (non)local-thermodynamic-equilibrium radiative transfer and estimated the [C i/CO] abundance ratio to be ~0:1 across the disks of NGC3627 and NGC4321, similar to previous large-scale findings in Galactic studies. However, this abundance ratio likely experiences a substantial increase, up to ~1 and &15 in NGC1808's starburst and NGC7469's strong AGN environments, respectively. This result is in line with the expectations for cosmic-ray dominated region (CRDR) and X-ray dominated region (XDR) chemistry. Finally, we do not find robust evidence for a generally CO-dark-and-C i-bright gas in the disk areas we probed. [ABSTRACT FROM AUTHOR]

Published
2023
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18. The PHANGS-MUSE survey

Author

Emsellem, Eric, primary, Schinnerer, Eva, additional, Santoro, Francesco, additional, Belfiore, Francesco, additional, Pessa, Ismael, additional, McElroy, Rebecca, additional, Blanc, Guillermo A., additional, Congiu, Enrico, additional, Groves, Brent, additional, Ho, I-Ting, additional, Kreckel, Kathryn, additional, Razza, Alessandro, additional, Sanchez-Blazquez, Patricia, additional, Egorov, Oleg, additional, Faesi, Chris, additional, Klessen, Ralf S., additional, Leroy, Adam K., additional, Meidt, Sharon, additional, Querejeta, Miguel, additional, Rosolowsky, Erik, additional, Scheuermann, Fabian, additional, Anand, Gagandeep S., additional, Barnes, Ashley T., additional, Bešlić, Ivana, additional, Bigiel, Frank, additional, Boquien, Médéric, additional, Cao, Yixian, additional, Chevance, Mélanie, additional, Dale, Daniel A., additional, Eibensteiner, Cosima, additional, Glover, Simon C. O., additional, Grasha, Kathryn, additional, Henshaw, Jonathan D., additional, Hughes, Annie, additional, Koch, Eric W., additional, Kruijssen, J. M. Diederik, additional, Lee, Janice, additional, Liu, Daizhong, additional, Pan, Hsi-An, additional, Pety, Jérôme, additional, Saito, Toshiki, additional, Sandstrom, Karin M., additional, Schruba, Andreas, additional, Sun, Jiayi, additional, Thilker, David A., additional, Usero, Antonio, additional, Watkins, Elizabeth J., additional, and Williams, Thomas G., additional

Published
2022
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19. PHANGS–MUSE: The H II region luminosity function of local star-forming galaxies

Author

Santoro, Francesco, primary, Kreckel, Kathryn, additional, Belfiore, Francesco, additional, Groves, Brent, additional, Congiu, Enrico, additional, Thilker, David A., additional, Blanc, Guillermo A., additional, Schinnerer, Eva, additional, Ho, I-Ting, additional, Diederik Kruijssen, J. M., additional, Meidt, Sharon, additional, Klessen, Ralf S., additional, Schruba, Andreas, additional, Querejeta, Miguel, additional, Pessa, Ismael, additional, Chevance, Mélanie, additional, Kim, Jaeyeon, additional, Emsellem, Eric, additional, McElroy, Rebecca, additional, Barnes, Ashley T., additional, Bigiel, Frank, additional, Boquien, Médéric, additional, Dale, Daniel A., additional, Glover, Simon C. O., additional, Grasha, Kathryn, additional, Lee, Janice, additional, Leroy, Adam K., additional, Pan, Hsi-An, additional, Rosolowsky, Erik, additional, Saito, Toshiki, additional, Sanchez-Blazquez, Patricia, additional, Watkins, Elizabeth J., additional, and Williams, Thomas G., additional

Published
2022
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