scholarly journals Luminosity Function of Old Globular Clusters in the SMC

1984 ◽  
Vol 78 ◽  
pp. 359-361
Author(s):  
M. Kontizas ◽  
E. Kontizas
Keyword(s):  
Globular Clusters ◽  
Luminosity Function ◽  
Star Cluster ◽  
Stellar Content ◽  
Luminosity Functions

Luminosity Functions (LFs) provide useful information on the stellar content of a star cluster. One of the problems of studying the colour-magnitude (c-m) diagrams in remote clusters is the contamination of cluster members with field stars. If all the stars of a cluster are measured in concentric rings one can reach the field and compare the c-m diagram of the field with that of the central areas. For the SMC where the field and cluster areas seem to have similar c-m diagrams, this method is not always useful and then the LF becomes an important tool of overcoming this obstacle.

scholarly journals Star cluster dynamics

2010 ◽  
Vol 368 (1913) ◽  
pp. 829-849 ◽  
Author(s):  
Enrico Vesperini
Keyword(s):  
Globular Clusters ◽  
Cluster Formation ◽  
Cluster Structure ◽  
Dynamical Evolution ◽  
Star Cluster ◽  
Stellar Content ◽  
Cluster Systems ◽  
Detailed Understanding ◽  
Term Evolution

Dynamical evolution plays a key role in shaping the current properties of star clusters and star cluster systems. A detailed understanding of the effects of evolutionary processes is essential to be able to disentangle the properties that result from dynamical evolution from those imprinted at the time of cluster formation. In this review, I focus my attention on globular clusters, and review the main physical ingredients driving their early and long-term evolution, describe the possible evolutionary routes and show how cluster structure and stellar content are affected by dynamical evolution.

scholarly journals Formation and Disruption of Globular Star Clusters

2002 ◽  
Vol 207 ◽  
pp. 566-576 ◽  
Author(s):  
S. Michael Fall ◽  
Qing Zhang
Keyword(s):  
Globular Clusters ◽  
Star Clusters ◽  
Mass Function ◽  
Star Cluster ◽  
Weak Dependence ◽  
Host Galaxies ◽  
Physical Processes ◽  
Cluster Systems ◽  
Luminosity Functions ◽  
Characteristic Mass

In the first part of this article, we review observations of the mass and luminosity functions of young and old star cluster systems. We also review some of the physical processes that may determine the characteristic mass of globular clusters and the form of their mass function. In the second part of this article, we summarize our models for the disruption of clusters and the corresponding evolution of the mass function. Much of our focus here is on understanding why the mass function of globular clusters has no more than a weak dependence on radius within their host galaxies.

scholarly journals Luminosity functions of globular clusters in five nearby spiral galaxies using HST/ACS images

2021 ◽  
Author(s):  
Luis Lomelí-Núñez ◽  
Y D Mayya ◽  
L H Rodríguez-Merino ◽  
P A Ovando ◽  
D Rosa-González
Keyword(s):  
Globular Clusters ◽  
Luminosity Function ◽  
Spiral Galaxies ◽  
Hubble Space Telescope ◽  
Luminosity Functions ◽  
Radial Density Distribution ◽  
Specific Frequency ◽  
Exponential Power ◽  
Turn Over ◽  
Poor Population

Abstract We here present the luminosity function (LF) of globular clusters (GCs) in five nearby spiral galaxies using the samples of GC candidates selected in Hubble Space Telescope mosaic images in F435W, F555W and F814W filters. Our search, which surpasses the fractional area covered by all previous searches in these galaxies, has resulted in the detection of 158 GC candidates in M81, 1123 in M101, 226 in NGC 4258, 293 in M51 and 173 in NGC 628. The LFs constructed from this dataset, after correcting for relatively small contamination from reddened young clusters, are lognormal in nature, which was hitherto established only for the Milky Way (MW) and Andromeda among spiral galaxies. The magnitude at the turn-over (TO) corresponds to MV0(TO)=-7.41±0.14 in four of the galaxies with Hubble types Sc or earlier, in excellent agreement with MV(TO) = −7.40 ± 0.10 for the MW. The TO magnitude is equivalent to a mass of ∼3 × 105 M⊙ for an old, metal-poor population. MV0(TO) is fainter by ∼1.16 magnitude for the fifth galaxy, M 101, which is of Hubble type Scd. The TO dependence on Hubble type implies that the GCs in early-type spirals are classical GCs, which have a universal TO, whereas the GC population in late-type galaxies is dominated by old disk clusters, which are in general less massive. The radial density distribution of GCs in our sample galaxies follows the Sérsic function with exponential power-law indices, and effective radii of 4.0–9.5 kpc. GCs in the sample galaxies have a mean specific frequency of 1.10 ± 0.24, after correcting for magnitude and radial incompleteness factors

Luminosity Functions for Globular Clusters

1998 ◽  
Vol 509 (1) ◽  
pp. 192-202 ◽  
Author(s):  
Fabio Silvestri ◽  
Paolo Ventura ◽  
Francesca D'Antona ◽  
Italo Mazzitelli
Keyword(s):  
Globular Clusters ◽  
Luminosity Functions

scholarly journals Carbon stars as standard candles – II. The median J magnitude as a distance indicator

2020 ◽  
Vol 501 (1) ◽  
pp. 933-947
Author(s):  
Javiera Parada ◽  
Jeremy Heyl ◽  
Harvey Richer ◽  
Paul Ripoche ◽  
Laurie Rousseau-Nepton
Keyword(s):  
Luminosity Function ◽  
Asymptotic Giant Branch ◽  
Distance Modulus ◽  
Asymptotic Giant Branch Stars ◽  
Luminosity Functions ◽  
Best Fitting ◽  
Distance Indicator ◽  
Ngc 6822 ◽  
The Given ◽  
Giant Branch Stars

ABSTRACT We introduce a new distance determination method using carbon-rich asymptotic giant branch stars (CS) as standard candles and the Large and Small Magellanic Clouds (LMC and SMC) as the fundamental calibrators. We select the samples of CS from the ((J − Ks)0, J0) colour–magnitude diagrams, as, in this combination of filters, CS are bright and easy to identify. We fit the CS J-band luminosity functions using a Lorentzian distribution modified to allow the distribution to be asymmetric. We use the parameters of the best-fitting distribution to determine if the CS luminosity function of a given galaxy resembles that of the LMC or SMC. Based on this resemblance, we use either the LMC or SMC as the calibrator and estimate the distance to the given galaxy using the median J magnitude ($\overline{J}$) of the CS samples. We apply this new method to the two Local Group galaxies NGC 6822 and IC 1613. We find that NGC 6822 has an ‘LMC-like’ CS luminosity function, while IC 1613 is more ‘SMC-like’. Using the values for the median absolute J magnitude for the LMC and SMC found in Paper I we find a distance modulus of μ0 = 23.54 ± 0.03 (stat) for NGC 6822 and μ0 = 24.34 ± 0.05 (stat) for IC 1613.

scholarly journals Very low-mass stellar content of the young supermassive Galactic star cluster Westerlund 1

2017 ◽  
Vol 602 ◽  
pp. A22 ◽  
Author(s):  
M. Andersen ◽  
M. Gennaro ◽  
W. Brandner ◽  
A. Stolte ◽  
G. de Marchi ◽  
...  
Keyword(s):  
Star Cluster ◽  
Stellar Content ◽  
Low Mass

scholarly journals Cosmological evolution of the AGN kinetic luminosity function

2006 ◽  
Vol 2 (S238) ◽  
pp. 65-70
Author(s):  
Andrea Merloni ◽  
Sebastian Heinz
Keyword(s):  
Galaxy Formation ◽  
Luminosity Function ◽  
Cosmological Evolution ◽  
Energy Output ◽  
Theoretical Assumption ◽  
X Ray ◽  
Spectrum Radio ◽  
Luminosity Functions ◽  
Jet Power ◽  
Joint Evolution

AbstractWe present a first attempt to derive the cosmological evolution of the kinetic luminosity function of AGN based on the joint evolution of the flat spectrum radio and hard X-ray selected AGN luminosity functions. An empirical correlation between jet power and radio core luminosity is found, which is consistent with the theoretical assumption that, below a certain Eddington ratio, SMBH accrete in a radiatively inefficient way, while most of the energy output is in the form of kinetic energy.We show how the redshift evolution of the kinetic power density from such a low-ṁ mode of accretion makes it a good candidate to explain the so-called “radio mode” of AGN feedback as outlined in many galaxy formation schemes.

scholarly journals Hidden infrared star clusters in our Galaxy: follow-up observations

2009 ◽  
Vol 5 (S266) ◽  
pp. 366-366
Author(s):  
Jura Borissova ◽  
Radostin Kurtev ◽  
Margaret M. Hanson ◽  
Leonid Georgiev ◽  
Valentin Ivanov ◽  
...  
Keyword(s):  
Globular Clusters ◽  
Star Cluster ◽  
Open Clusters ◽  
Star Formation History ◽  
Stellar Disk ◽  
Physical Parameters ◽  
Formation History ◽  
The Galaxy ◽  
History Of ◽  
Infrared Star

AbstractWe are reporting some recent results from our long-term program aimed at characterizing the obscured present-day star cluster population in the Galaxy. Our goal is to expand the current census of the Milky Way's inner stellar disk to guide models seeking to understand the structure and recent star-formation history of our Galaxy. The immediate goal is to derive accurate cluster physical parameters using precise infrared photometry and spectroscopy. So far, we observed approximately 60 star cluster candidates selected from different infrared catalogs. Their nature, reddening, distance, age and mass are analyzed. Two of them, Mercer 3 and Mercer 5, are new obscured Milky Way globular clusters. Among the newly identified open clusters, the objects [DBS2003] 179, Mercer 23, Mercer 30, Mercer 70, and [DBS2003] 106 are particularly interesting because they contain massive young OB and Wolf–Rayet stars with strong emission lines.

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