scholarly journals Linking globular cluster formation at low and high redshift through the age–metallicity relation in E-MOSAICS

2020 ◽  
Vol 500 (4) ◽  
pp. 4768-4778
Author(s):  
Danny Horta ◽  
Meghan E Hughes ◽  
Joel L Pfeffer ◽  
Nate Bastian ◽  
J M Diederik Kruijssen ◽  
...  
Keyword(s):  
Star Formation ◽  
Formation Mechanism ◽  
Globular Clusters ◽  
High Redshift ◽  
Cluster Formation ◽  
Star Cluster ◽  
Host Galaxies ◽  
Massive Galaxies ◽  
Low Metallicity ◽  
Massive Clusters

ABSTRACT We set out to compare the age–metallicity relation (AMR) of massive clusters from Magellanic Cloud mass galaxies in the E-MOSAICS suite of numerical cosmological simulations with an amalgamation of observational data of massive clusters in the Large and Small Magellanic Clouds (LMC/SMC). We aim to test if: (i) star cluster formation proceeds according to universal physical processes, suggestive of a common formation mechanism for young-massive clusters (YMCs), intermediate-age clusters (IACs), and ancient globular clusters (GCs); (ii) massive clusters of all ages trace a continuous AMR; and (iii) the AMRs of smaller mass galaxies show a shallower relation when compared to more massive galaxies. Our results show that, within the uncertainties, the predicted AMRs of L/SMC-mass galaxies with similar star formation histories to the L/SMC follow the same relation as observations. We also find that the metallicity at which the AMR saturates increases with galaxy mass, which is also found for the field star AMRs. This suggests that relatively low-metallicity clusters can still form in dwarfs galaxies. Given our results, we suggest that ancient GCs share their formation mechanism with IACs and YMCs, in which GCs are the result of a universal process of star cluster formation during the early episodes of star formation in their host galaxies.

scholarly journals Star cluster formation and cloud dispersal by radiative feedback: dependence on metallicity and compactness

2020 ◽  
Vol 497 (3) ◽  
pp. 3830-3845 ◽  
Author(s):  
Hajime Fukushima ◽  
Hidenobu Yajima ◽  
Kazuyuki Sugimura ◽  
Takashi Hosokawa ◽  
Kazuyuki Omukai ◽  
...  
Keyword(s):  
Star Formation ◽  
Massive Stars ◽  
Cluster Formation ◽  
Star Clusters ◽  
Star Cluster ◽  
Star Forming ◽  
Dynamical Time ◽  
Low Metallicity ◽  
Higher Temperature ◽  
Dust Attenuation

ABSTRACT We study star cluster formation in various environments with different metallicities and column densities by performing a suite of 3D radiation hydrodynamics simulations. We find that the photoionization feedback from massive stars controls the star formation efficiency (SFE) in a star-forming cloud, and its impact sensitively depends on the gas metallicity Z and initial cloud surface density Σ. At Z = 1 Z⊙, SFE increases as a power law from 0.03 at Σ = 10 M⊙ pc−2 to 0.3 at $\Sigma = 300\,\mathrm{M}_{\odot }\, {\rm pc^{-2}}$. In low-metallicity cases $10^{-2}\!-\!10^{-1}\, \mathrm{Z}_{\odot }$, star clusters form from atomic warm gases because the molecule formation time is not short enough with respect to the cooling or dynamical time. In addition, the whole cloud is disrupted more easily by expanding H ii bubbles that have higher temperature owing to less efficient cooling. With smaller dust attenuation, the ionizing radiation feedback from nearby massive stars is stronger and terminate star formation in dense clumps. These effects result in inefficient star formation in low-metallicity environments: the SFE drops by a factor of ∼3 at Z = 10−2 Z⊙ compared to the results for Z = 1 Z⊙, regardless of Σ. Newborn star clusters are also gravitationally less bound. We further develop a new semi-analytical model that can reproduce the simulation results well, particularly the observed dependencies of the SFEs on the cloud surface densities and metallicities.

scholarly journals Quasar Metal Abundances & Host Galaxy Evolution

2009 ◽  
Vol 5 (S265) ◽  
pp. 171-178
Author(s):  
Fred Hamann ◽  
Leah E. Simon
Keyword(s):  
Star Formation ◽  
Galaxy Evolution ◽  
High Redshift ◽  
Big Bang ◽  
Host Galaxy ◽  
Host Galaxies ◽  
Massive Galaxies ◽  
Central Regions ◽  
Metal Abundances ◽  
The Big Bang

AbstractHigh-redshift quasars provide a unique glimpse into the early evolution of massive galaxies. The physical processes that trigger major bursts of star formation in quasar host galaxies (mergers and interactions) probably also funnel gas into the central regions to grow the super-massive black holes (SMBHs) and ignite the luminous quasar phenomenon. The globally dense environments where this occurs were probably also among the first to collapse and manufacture stars in significant numbers after the big bang. Measurements of the elemental abundances near quasars place important constraints on the nature, timing and extent of this star formation. A variety of studies using independent emission and absorption line diagnostics have shown that quasar environments have gas-phase metallicities that are typically a few times solar at all observed redshifts. These results are consistent with galaxy evolution scenarios in which large amounts of star formation (e.g., in the central regions) precede the visibly bright quasar phase. An observed trend for higher metallicities in more luminmous quasars (powered by more massive SMBHs) is probably tied to the well-known mass–metallicity relation among ordinary galaxies. This correlation and the absence of a trend with redshift indicate that mass is a more important parameter in the evolution than the time elapsed since the big bang.

scholarly journals On the initial mass-radius relation of stellar clusters

2021 ◽  
Author(s):  
Nick Choksi ◽  
J M Diederik Kruijssen
Keyword(s):  
High Pressure ◽  
Globular Clusters ◽  
High Redshift ◽  
Cluster Formation ◽  
Stellar Clusters ◽  
Population Synthesis ◽  
Star Forming ◽  
Massive Clusters ◽  
Good Agreement ◽  
Environmental Dependence

Abstract Young stellar clusters across nearly five orders of magnitude in mass appear to follow a power-law mass-radius relationship (MRR), $R_{\star }\propto M_{\star }^{\alpha }$, with α ≈ 0.2 − 0.33. We develop a simple analytic model for the cluster mass-radius relation. We consider a galaxy disc in hydrostatic equilibrium, which hosts a population of molecular clouds that fragment into clumps undergoing cluster formation and feedback-driven expansion. The model predicts a mass-radius relation of $R_{\star }\propto M_{\star }^{1/2}$ and a dependence on the kpc-scale gas surface density $R_{\star }\propto \Sigma _{\rm g}^{-1/2}$, which results from the formation of more compact clouds (and cluster-forming clumps within) at higher gas surface densities. This environmental dependence implies that the high-pressure environments in which the most massive clusters can form also induce the formation of clusters with the smallest radii, thereby shallowing the observed MRR at high-masses towards the observed $R_{\star }\propto M_{\star }^{1/3}$. At low cluster masses, relaxation-driven expansion induces a similar shallowing of the MRR. We combine our predicted MRR with a simple population synthesis model and apply it to a variety of star-forming environments, finding good agreement. Our model predicts that the high-pressure formation environments of globular clusters at high redshift naturally led to the formation of clusters that are considerably more compact than those in the local Universe, thereby increasing their resilience to tidal shock-driven disruption and contributing to their survival until the present day.

scholarly journals The SUNBIRD survey: characterizing the super star cluster populations of intensely star-forming galaxies

2015 ◽  
Vol 12 (S316) ◽  
pp. 70-76
Author(s):  
Zara Randriamanakoto ◽  
Petri Väisänen
Keyword(s):  
Star Formation ◽  
Adaptive Optics ◽  
Near Infrared ◽  
Cluster Formation ◽  
Formation Rate ◽  
Star Clusters ◽  
Power Laws ◽  
Star Cluster ◽  
Host Galaxies ◽  
Star Forming

AbstractSuper star clusters (SSCs) represent the youngest and most massive form of known gravitationally bound star clusters in the Universe. They are born abundantly in environments that trigger strong and violent star formation. We investigate the properties of these massive SSCs in a sample of 42 nearby starbursts and luminous infrared galaxies. The targets form the sample of the SUperNovae and starBursts in the InfraReD (SUNBIRD) survey that were imaged using near-infrared (NIR) K-band adaptive optics mounted on the Gemini/NIRI and the VLT/NaCo instruments. Results from i) the fitted power-laws to the SSC K-band luminosity functions, ii) the NIR brightest star cluster magnitude − star formation rate (SFR) relation and iii) the star cluster age and mass distributions have shown the importance of studying SSC host galaxies with high SFR levels to determine the role of the galactic environments in the star cluster formation, evolution and disruption mechanisms.

scholarly journals Star Formation Through Cosmic Time

2006 ◽  
Vol 2 (S235) ◽  
pp. 261-267
Author(s):  
Michael A. Dopita
Keyword(s):  
Star Formation ◽  
Galaxy Formation ◽  
Globular Clusters ◽  
High Redshift ◽  
Cosmic Time ◽  
Star Formation History ◽  
Massive Black Holes ◽  
Massive Galaxies ◽  
History Of ◽  
Population Iii Stars

AbstractThis paper reviews the star formation history of the Universe, from the first stars to the current day, with emphasis on the critical analysis of the techniques that have been used to determine it, especially considering the role of dust. We consider the first population of stars, the Population III stars, were formed at redshifts ranging as high as z ~ 60, the formation of the Globular Clusters, the main epoch of galaxy formation. In the sub-mm galaxies and high-redshift radio galaxies the collapse of massive galaxies was surprisingly rapid, and that the growth of super-massive black holes at their centers provides the energy input to eject the galactic interstellar medium while at the same time precipitating a final burst of star formation and the ejection of their ISM so that the subsequent evolution of these galaxies is passive.

scholarly journals Probing Globular Cluster Formation in Low Metallicity Dwarf Galaxies

2008 ◽  
Vol 4 (S255) ◽  
pp. 366-369
Author(s):  
Kelsey E. Johnson ◽  
Leslie K. Hunt ◽  
Amy E. Reines
Keyword(s):  
Globular Clusters ◽  
Massive Star ◽  
Dwarf Galaxies ◽  
Cluster Formation ◽  
Formation Rate ◽  
Star Clusters ◽  
Initial Study ◽  
Spectral Energy ◽  
Massive Galaxies ◽  
Low Metallicity

AbstractThe ubiquitous presence of globular clusters around massive galaxies today suggests that these extreme star clusters must have been formed prolifically in the earlier universe in low-metallicity galaxies. Numerous adolescent and massive star clusters are already known to be present in a variety of galaxies in the local universe; however most of these systems have metallicities of 12 + log(O/H) > 8, and are thus not representative of the galaxies in which today's ancient globular clusters were formed. In order to better understand the formation and evolution of these massive clusters in environments with few heavy elements, we have targeted several low-metallicity dwarf galaxies with radio observations, searching for newly-formed massive star clusters still embedded in their birth material. The galaxies in this initial study are HS 0822+3542, UGC 4483, Pox 186, and SBS 0335-052, all of which have metallicities of 12 + log(O/H) < 7.75. While no thermal radio sources, indicative of natal massive star clusters, are found in three of the four galaxies, SBS 0335-052 hosts two such objects, which are incredibly luminous. The radio spectral energy distributions of these intense star-forming regions in SBS 0335-052 suggest the presence of ~12,000 equivalent O-type stars, and the implied star formation rate is nearing the maximum starburst intensity limit.

scholarly journals Low-luminosity Galaxies in the Early Universe Have Observed Sizes Similar to Star Cluster Complexes

2021 ◽  
Vol 162 (6) ◽  
pp. 255
Author(s):  
R. J. Bouwens ◽  
G. D. Illingworth ◽  
P. G. van Dokkum ◽  
B. Ribeiro ◽  
P. A. Oesch ◽  
...  
Keyword(s):  
Globular Cluster ◽  
Globular Clusters ◽  
High Redshift ◽  
Cluster Formation ◽  
Star Cluster ◽  
Single Star ◽  
Cluster Complexes ◽  
Star Forming ◽  
Comparison Sample ◽  
Upper Limits

Abstract We compare the sizes and luminosities of faint z = 6–8 galaxies magnified by the Hubble Frontier Fields clusters with star-forming regions, as well as more evolved objects, in the nearby universe. Our high-redshift comparison sample includes 330 z = 6–8 galaxies, for which size measurements were made as part of a companion study where lensing magnifications were estimated from various public models. Accurate size measurements for these sources are complicated by the lens model uncertainties, but other results and arguments suggest that faint galaxies are small, as discussed in a companion study. The measured sizes for sources in our comparison sample range from <50 pc to ∼500 pc. For many of the lowest-luminosity sources, extremely small sizes are inferred, reaching individual sizes as small as 10–30 pc, with several sources in the 10–15 pc range with our conservative magnification limits. The sizes and luminosities are similar to those of single star cluster complexes like 30 Doradus in the lower-redshift universe and—in a few cases—super star clusters. The identification of these compact, faint star-forming sources in the z ∼ 6–8 universe also allows us to set upper limits on the proto-globular cluster luminosity function at z ∼ 6. By comparisons of the counts and sizes with recent models, we rule out (with some caveats) proto-globular cluster formation scenarios favoring substantial (ξ = 10) post-formation mass loss and set useful upper limits on others. Our size results suggest we may be very close to discovering a bona fide population of forming globular clusters at high redshift.

scholarly journals Globular Clusters in the Local Group

2014 ◽  
Vol 10 (S312) ◽  
pp. 157-170 ◽  
Author(s):  
Eva K. Grebel
Keyword(s):  
Globular Cluster ◽  
Globular Clusters ◽  
Local Group ◽  
Cluster Formation ◽  
Light Element ◽  
Indirect Evidence ◽  
Host Galaxies ◽  
Ample Evidence ◽  
Massive Galaxies ◽  
Age Range

AbstractOnly twelve of the > 76 Local Group galaxies contain globular clusters, showing a broad range of specific frequencies. Here we summarize the properties of these globular cluster systems. Many host galaxies contain very old globulars, but in some globular cluster formation may have been delayed. An age range of several Gyr is common. Except for the inner regions of the spirals, old globular clusters tend to be metal-poor. Increasingly, light element variations and hints of multiple stellar populations are being found also in extragalactic globulars. There is ample evidence for globular cluster accretion from dwarfs onto massive galaxies, but its magnitude has yet to be quantified. Caution is needed to avoid overinterpreting indirect evidence.

Young massive clusters in Arp 299

2019 ◽  
Vol 14 (S351) ◽  
pp. 143-146
Author(s):  
Zara Randriamanakoto ◽  
Petri Väisänen
Keyword(s):  
Star Formation ◽  
Globular Clusters ◽  
Cluster Formation ◽  
Age Distribution ◽  
Star Cluster ◽  
Luminous Infrared Galaxies ◽  
Star Formation Activity ◽  
Formation And Evolution ◽  
Using Data ◽  
Formation Efficiency

AbstractBecause of their young ages and compact densities, young massive star clusters (YMCs) are widely considered as potential proto-globular clusters. They are ubiquitous in environments with ongoing star formation activity such as interacting luminous infrared galaxies. To determine the galactic environmental effects on the star cluster formation and evolution, we study the YMC population of Arp 299 (NGC 3690E/NGC 3690W) using data taken with the HST WFC3/UVIS camera. By fitting the multiband photometry with the Yggdrasil models, we derive the star cluster masses, ages and extinction. While the cluster mass-galactocentric radius relation of NGC 3690E indicates that there could be an influence of the gas density distribution on the cluster formation, the age distribution of the western component suggests that YMCs in that galaxy endure stronger disruption mechanisms. With a cluster formation efficiency of 19 percent, star formation happening in bound clusters in Arp 299 is 3–5 times higher than that of a typical normal spiral.

scholarly journals The Imprints Of Galactic Environment On Cluster Formation and Evolution

2015 ◽  
Vol 12 (S316) ◽  
pp. 17-24
Author(s):  
Angela Adamo
Keyword(s):  
Star Formation ◽  
Formation Process ◽  
Globular Clusters ◽  
High Redshift ◽  
Cluster Formation ◽  
Large Population ◽  
Star Clusters ◽  
Young Star ◽  
Star Formation History ◽  
Formation History

AbstractYoung star clusters (YSCs) appear to be a ubiquitous product of star formation in local galaxies, thus, they can be used to study the star formation process at work in their host galaxies. Moreover, YSCs are intrinsically brighter that single stars, potentially becoming the most important tracers of the recent star formation history in galaxies in the local Universe. In local galaxies, we also witness the presence of a large population of evolved star clusters, commonly called globular clusters (GCs). GCs peak formation history is very close to the redshift (z ~ 2) when the cosmic star formation history reached the maximum. Therefore, GCs are usually associated to extreme star formation episodes in high-redshift galaxies. It is yet not clear whether YSCs and GCs share a similar formation process (same physics under different interstellar medium conditions) and evolution process, and whether the former can be used as progenitor analogs of the latter. In this invited contribution, I review general properties of YSC populations in local galaxies. I will summarise some of the current open questions in the field, with particular emphasis to whether or not galactic environments, where YSCs form, leave imprints on the nested populations. The importance of this rapidly developing field can be crucial in understanding GC formation and possibly the galactic environment condition where this ancient population formed.

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