scholarly journals Nuclear star clusters

2009 ◽  
Vol 5 (S266) ◽  
pp. 58-63 ◽  
Author(s):  
Torsten Böker
Keyword(s):  
Black Holes ◽  
Structural Properties ◽  
Galaxy Evolution ◽  
Globular Clusters ◽  
Star Clusters ◽  
Supermassive Black Holes ◽  
Subsequent Growth ◽  
Local Universe ◽  
Fundamental Plane ◽  
Evolutionary Connection

AbstractThe centers of most galaxies in the local Universe are occupied by compact, barely resolved sources. Based on their structural properties, position in the Fundamental Plane, and integrated spectra, these sources clearly have a stellar origin. They are therefore called ‘nuclear star clusters’ (NCs) or ‘stellar nuclei’. NCs are found in galaxies of all Hubble types, suggesting that their formation is intricately linked to galaxy evolution. Here, I review some recent studies of NCs, describe ideas for their formation and subsequent growth, and touch on their possible evolutionary connection with both supermassive black holes and globular clusters.

scholarly journals Nuclear star clusters

2020 ◽  
Vol 28 (1) ◽  
Author(s):  
Nadine Neumayer ◽  
Anil Seth ◽  
Torsten Böker
Keyword(s):  
Black Holes ◽  
Galaxy Evolution ◽  
Globular Clusters ◽  
Current Knowledge ◽  
Star Clusters ◽  
Host Galaxies ◽  
Massive Galaxies ◽  
Wide Range ◽  
The Galaxy ◽  
Ultimate Fate

AbstractWe review the current knowledge about nuclear star clusters (NSCs), the spectacularly dense and massive assemblies of stars found at the centers of most galaxies. Recent observational and theoretical works suggest that many NSC properties, including their masses, densities, and stellar populations, vary with the properties of their host galaxies. Understanding the formation, growth, and ultimate fate of NSCs, therefore, is crucial for a complete picture of galaxy evolution. Throughout the review, we attempt to combine and distill the available evidence into a coherent picture of NSC evolution. Combined, this evidence points to a clear transition mass in galaxies of $$\sim 10^9\,M_\odot$$ ∼ 10 9 M ⊙ where the characteristics of nuclear star clusters change. We argue that at lower masses, NSCs are formed primarily from globular clusters that inspiral into the center of the galaxy, while at higher masses, star formation within the nucleus forms the bulk of the NSC. We also discuss the co-existence of NSCs and central black holes, and how their growth may be linked. The extreme densities of NSCs and their interaction with massive black holes lead to a wide range of unique phenomena including tidal disruption and gravitational-wave events. Finally, we review the evidence that many NSCs end up in the halos of massive galaxies stripped of the stars that surrounded them, thus providing valuable tracers of the galaxies’ accretion histories.

scholarly journals The Arkansas Galaxy Evolution Survey: Supermassive Black Holes in the Universe

2009 ◽  
Vol 5 (S267) ◽  
pp. 210-210
Author(s):  
M. S. Seigar ◽  
D. Kennefick ◽  
J. Kennefick ◽  
C. H. S. Lacy ◽  
J. C. Berrier ◽  
...  
Keyword(s):  
Black Holes ◽  
Galaxy Evolution ◽  
Mass Function ◽  
Supermassive Black Holes ◽  
Active Galaxies ◽  
Local Universe ◽  
Apparent Decrease ◽  
Work Done ◽  
The Universe ◽  
Observational Record

Work done to date on the SMBH mass function has brought to light some interesting puzzles, the best known of which is cosmic downsizing. The solution to this problem is based upon the methodology by which we determine SMBH masses, which comes mainly from studies of active galaxies. The most massive SMBHs cease to be active at earlier epochs than their less massive counterparts, thus leading to an apparent decrease in the SMBH mass function with time. The larger SMBHs should still be present in the local Universe, but they lie in quiescent galaxies. This lack of certainty reflects the biggest gap in the observational record – the mass of SMBHs in quiescent galaxies.

scholarly journals Feedback by supermassive black holes in galaxy evolution: impacts of accretion and outflows on the star formation rate

2019 ◽  
Vol 486 (2) ◽  
pp. 1509-1522 ◽  
Author(s):  
Mojtaba Raouf ◽  
Joseph Silk ◽  
Stanislav S Shabala ◽  
Gary A Mamon ◽  
Darren J Croton ◽  
...  
Keyword(s):  
Black Holes ◽  
Star Formation ◽  
Galaxy Evolution ◽  
Star Formation Rate ◽  
Formation Rate ◽  
Supermassive Black Holes

scholarly journals C iv black hole mass measurements with the Australian Dark Energy Survey (OzDES)

2019 ◽  
Vol 487 (3) ◽  
pp. 3650-3663 ◽  
Author(s):  
J K Hoormann ◽  
P Martini ◽  
T M Davis ◽  
A King ◽  
C Lidman ◽  
...  
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
Dark Energy ◽  
Emission Line ◽  
Galaxy Evolution ◽  
Supermassive Black Holes ◽  
Black Hole Mass ◽  
Mass Measurements ◽  
Dark Energy Survey ◽  
Energy Survey

ABSTRACT Black hole mass measurements outside the local Universe are critically important to derive the growth of supermassive black holes over cosmic time, and to study the interplay between black hole growth and galaxy evolution. In this paper, we present two measurements of supermassive black hole masses from reverberation mapping (RM) of the broad C iv emission line. These measurements are based on multiyear photometry and spectroscopy from the Dark Energy Survey Supernova Program (DES-SN) and the Australian Dark Energy Survey (OzDES), which together constitute the OzDES RM Program. The observed reverberation lag between the DES continuum photometry and the OzDES emission line fluxes is measured to be $358^{+126}_{-123}$ and $343^{+58}_{-84}$ d for two quasars at redshifts of 1.905 and 2.593, respectively. The corresponding masses of the two supermassive black holes are 4.4 × 109 and 3.3 × 109 M⊙, which are among the highest redshift and highest mass black holes measured to date with RM studies. We use these new measurements to better determine the C iv radius−luminosity relationship for high-luminosity quasars, which is fundamental to many quasar black hole mass estimates and demographic studies.

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