scholarly journals The anatomy of a star-forming galaxy II: FUV heating via dust

2020 ◽  
Vol 499 (2) ◽  
pp. 2028-2041
Author(s):  
S M Benincasa ◽  
J W Wadsley ◽  
H M P Couchman ◽  
A R Pettitt ◽  
B W Keller ◽  
...  
Keyword(s):  
Star Formation ◽  
Energy Budget ◽  
Star Clusters ◽  
Young Star ◽  
Star Forming ◽  
Neutral Gas ◽  
Feedback Model ◽  
Science Application ◽  
Far Ultraviolet ◽  
Young Star Clusters

ABSTRACT Far-ultraviolet (FUV) radiation greatly exceeds UV, supernovae (SNe), and winds in the energy budget of young star clusters but is poorly modelled in galaxy simulations. We present results of the first isolated galaxy disc simulations to include photoelectric heating of gas via dust grains from FUV radiation self-consistently, using a ray-tracing approach that calculates optical depths along the source–receiver sightline. This is the first science application of the TREVR radiative transfer algorithm. We find that FUV radiation alone cannot regulate star formation. However, FUV radiation produces warm neutral gas and is able to produce regulated galaxies with realistic scale heights. FUV is also a long-range feedback and is more important in the outer discs of galaxies. We also use the superbubble feedback model, which depends only on the SN energy per stellar mass, is more physically realistic than common, parameter-driven alternatives and thus better constrains SN feedback impacts. FUV and SNe together can regulate star formation without producing too much hot ionized medium and with less disruption to the interstellar medium compared to SNe alone.

scholarly journals Metallicity and X-ray luminosity variations in NGC 922

2020 ◽  
Vol 500 (1) ◽  
pp. 962-975
Author(s):  
K Kouroumpatzakis ◽  
A Zezas ◽  
A Wolter ◽  
A Fruscione ◽  
K Anastasopoulou ◽  
...  
Keyword(s):  
Star Formation ◽  
Stellar Population ◽  
Massive Stars ◽  
Star Clusters ◽  
Young Star ◽  
X Ray ◽  
Star Forming ◽  
Star Forming Regions ◽  
Main Driver ◽  
Young Star Clusters

ABSTRACT We present a systematic study of the metallicity variations within the collisional ring galaxy NGC 922 based on long-slit optical spectroscopic observations. We find a metallicity difference between star-forming regions in the bulge and the ring, with metallicities ranging from almost solar to significantly sub-solar ($\rm {[12+\log (O/H)]\sim 8.2}$). We detect $\rm{He\,{\small I}}$ emission in all the studied regions of the bulge and the ring, indicating ionization from massive stars associated with recent (<10 Myr) star formation, in agreement with the presence of very young star clusters. We find an anticorrelation between the X-ray luminosity and metallicity of the sub-galactic regions of NGC 922. The different regions have similar stellar population ages, leaving metallicity as the main driver of the anticorrelation. The dependence of the X-ray emission of the different regions in NGC 922 on metallicity is in agreement with similar studies of the integrated X-ray output of galaxies and predictions from X-ray binary population models.

scholarly journals The R136 star cluster dissected withHubble Space Telescope/STIS. I. Far-ultraviolet spectroscopic census and the origin of He ii λ1640 in young star clusters

2016 ◽  
Vol 458 (1) ◽  
pp. 624-659 ◽  
Author(s):  
Paul A. Crowther ◽  
S. M. Caballero-Nieves ◽  
K. A. Bostroem ◽  
J. Maíz Apellániz ◽  
F. R. N. Schneider ◽  
...  
Keyword(s):  
Star Clusters ◽  
Young Star ◽  
Star Cluster ◽  
Space Telescope ◽  
Far Ultraviolet ◽  
Young Star Clusters

scholarly journals Constraining star formation timescales with molecular gas and young star clusters

2019 ◽  
Vol 15 (S352) ◽  
pp. 350-352
Author(s):  
Kathryn Grasha ◽  
Daniela Calzetti
Keyword(s):  
Star Formation ◽  
Galaxy Evolution ◽  
Star Clusters ◽  
Young Star ◽  
Molecular Gas ◽  
Gas Reservoirs ◽  
Multi Wavelength ◽  
Predictive Theory ◽  
Young Star Clusters ◽  
Co Observations

AbstractStar formation provides insight into the physical processes that govern the transformation of gas into stars. A key missing piece in a predictive theory of star formation is the link between scales of individual stars and star clusters up to entire galaxies. LEGUS is now providing the information to test the overall organization and spatial evolution of star formation. We present our latest findings of using star clusters from LEGUS combined with ALMA CO observations to investigate the transition from molecular gas to star formation in local galaxies. This work paves the way for future JWST observations of the embedded phase of star formation, the last missing ingredient to connect young star clusters and their relation with gas reservoirs. Multi-wavelength studies of local galaxies and their stellar and gas components will help shed light on early phases of galaxy evolution and properties of the ISM at high-z.

scholarly journals Formation of Young Star Clusters

2005 ◽  
Vol 13 ◽  
pp. 358-362
Author(s):  
Bruce Elmegreen
Keyword(s):  
Star Formation ◽  
Energy Dissipation ◽  
Star Clusters ◽  
Young Star ◽  
Formation Processes ◽  
Stellar Objects ◽  
Scale Free ◽  
Self Gravity ◽  
Young Star Clusters ◽  
Mass Functions

AbstractTurbulence, self-gravity, and cooling convert most of the interstellar medium into cloudy structures that form stars. Turbulence compresses the gas into clouds directly and it moves pre-existing clouds around passively when there are multiple phases of temperature. Self-gravity also partitions the gas into clouds, forming giant regular complexes in spiral arms and in resonance rings and contributing to the scale-free motions generated by turbulence. Dense clusters form in the most strongly self-gravitating cores of these clouds, often triggered by compression from local stars. Pre-star formation processes inside clusters are not well observed, but the high formation rates and high densities of pre-stellar objects, and their power law mass functions suggest that turbulence, self-gravity, and energy dissipation are involved there too.

scholarly journals The Initial Mass Function in Young Star Clusters

1986 ◽  
Vol 7 ◽  
pp. 489-499
Author(s):  
Hans Zinnecker
Keyword(s):  
Star Formation ◽  
Recent Work ◽  
Star Clusters ◽  
Mass Function ◽  
Young Star ◽  
Initial Mass Function ◽  
Initial Mass ◽  
Stellar Content ◽  
Young Star Clusters ◽  
The Imf

AbstractThis review discusses both the earlier and the most recent work on the IMF in young star clusters. It is argued that the study of the stellar content of young star clusters offers the best chance of developing a theory of star formation and of the IMF.

scholarly journals Formation of nuclear rings of barred galaxies and star formation therein

2013 ◽  
Vol 9 (S303) ◽  
pp. 43-53 ◽  
Author(s):  
Woong-Tae Kim ◽  
Woo-Young Seo ◽  
Yonghwi Kim
Keyword(s):  
Star Formation ◽  
Formation Rate ◽  
Star Clusters ◽  
Young Star ◽  
Centrifugal Barrier ◽  
Barred Galaxies ◽  
Contact Points ◽  
Nuclear Ring ◽  
Substructure Formation ◽  
Young Star Clusters

AbstractBarred galaxies contain substructures such as a pair of dust lanes and nuclear rings, with the latter being sites of intense star formation. We study the substructure formation as well as star formation in nuclear rings using numerical simulations. We find that nuclear rings form not by the Lindblad resonances, as previously thought, but by the centrifugal barrier that inflowing gas along dust lanes cannot overcome. This predicts a smaller ring in a more strongly barred galaxy, consistent with observations. Star formation rate (SFR) in a nuclear ring is determined primarily by the mass inflow rate to the ring. In our models, the SFR typically shows a short strong burst associated with the rapid gas infall and stays very small for the rest of the evolution. When the SFR is low, ages of young star clusters exhibit an azimuthal gradient along the ring since star formation takes place mostly near the contact points between the dust lanes and the nuclear ring. When the SFR is large, on the other hand, star formation is widely distributed throughout the whole length of the ring, with no apparent age gradient of star clusters. Since observed ring star formation appears long-lived with episodic bursts, our results suggest that the bar region should be replenished continually with fresh gas from outside.

scholarly journals Fourth Day of Creation: The Proto-history of Young Stars, Star Streams, and Exoplanets Near the Sun

2015 ◽  
Vol 10 (S314) ◽  
pp. 1-7
Author(s):  
Virginia Trimble
Keyword(s):  
Star Formation ◽  
Milky Way ◽  
Star Clusters ◽  
Young Star ◽  
Young Stars ◽  
The Sun ◽  
Complex Processes ◽  
History Of ◽  
Moving Groups ◽  
Young Star Clusters

AbstractItems of scientific knowledge at any moment in time have pre-histories when they were debated, doubted, or absolutely denied. The examples considered here are the admitted facts that star formation is an on-going process in the Milky Way, that there are young moving groups (the products of young star clusters in the process of dissolution and perhaps more complex processes), and that planets orbiting other stars are common. It is hard to imagine any of these ceasing to be part of core astronomical knowledge, but you are advised not to place large bets on this.

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