scholarly journals MOCCA survey database I: Preliminary mock Extra Galactic Globular Cluster observations

2019 ◽  
Vol 14 (S351) ◽  
pp. 122-125
Author(s):  
Agostino Leveque ◽  
Mirosław Giersz
Keyword(s):  
Spatial Distribution ◽  
Globular Cluster ◽  
Globular Clusters ◽  
Surface Brightness ◽  
Stellar Population ◽  
Dynamical Evolution ◽  
The Other ◽  
Population Synthesis ◽  
Stellar Population Synthesis ◽  
Preliminary Study

AbstractThe photometric properties that we could observe for Extra-Galactic Globular Clusters (EGGCs) are the integrated light of the system and for nearby EGGCs it also is possible to measure both half-light radii and the color spatial distribution, e.g. for areas smaller and larger than the half-light radius. No information about the internal dynamical state of the system could be directly obtained from observations. On the other hand, simulations of Globular Clusters (GCs) can provide detailed information about the dynamical evolution of the system.We present a preliminary study of EGGCs’ photometric properties for different dynamical evolutionary stages. We apply this study to 12Gyr old GCs simulated as part of the MOCCA Survey Database. We determine the magnitudes in different bands from their projected snapshots using the Flexible Stellar Population Synthesis (FSPS) code and we measure the half-light radii from the surface brightness.

scholarly journals On the survivability of planets in young massive clusters and its implication of planet orbital architectures in globular clusters

2019 ◽  
Vol 489 (3) ◽  
pp. 4311-4321 ◽  
Author(s):  
Maxwell X Cai ◽  
S Portegies Zwart ◽  
M B N Kouwenhoven ◽  
Rainer Spurzem
Keyword(s):  
Globular Cluster ◽  
Time Scale ◽  
Globular Clusters ◽  
Semimajor Axis ◽  
Stellar System ◽  
Dynamical Evolution ◽  
The Other ◽  
Crossing Time ◽  
Massive Clusters ◽  
Full Investigation

ABSTRACT As of 2019 August, among the more than 4000 confirmed exoplanets, only one has been detected in a globular cluster (GC) M4. The scarce of exoplanet detections motivates us to employ direct N-body simulations to investigate the dynamical stability of planets in young massive clusters (YMC), which are potentially the progenitors of GCs. In an N = 128 k cluster of virial radius 1.7 pc (comparable to Westerlund-1), our simulations show that most wide-orbit planets (a ≥ 20 au) will be ejected within a time-scale of 10 Myr. Interestingly, more than $70{{\ \rm per\ cent}}$ of planets with a < 5 au survive in the 100 Myr simulations. Ignoring planet–planet scattering and tidal damping, the survivability at t Myr as a function of initial semimajor axis a0 in au in such a YMC can be described as fsurv(a0, t) = −0.33log10(a0)(1 − e−0.0482t) + 1. Upon ejection, about $28.8{{\ \rm per\ cent}}$ of free-floating planets (FFPs) have sufficient speeds to escape from the host cluster at a crossing time-scale. The other FFPs will remain bound to the cluster potential, but the subsequent dynamical evolution of the stellar system can result in the delayed ejection of FFPs from the host cluster. Although a full investigation of planet population in GCs requires extending the simulations to multiGyr, our results suggest that wide-orbit planets and free-floating planets are unlikely to be found in GCs.

scholarly journals Imaging of NGC 5907's stellar stream

2015 ◽  
Vol 11 (S317) ◽  
pp. 324-325
Author(s):  
Seppo Laine ◽  
Carl J. Grillmair ◽  
David Martínez–Delgado ◽  
Aaron J. Romanowsky ◽  
Peter L. Capak ◽  
...  
Keyword(s):  
Surface Brightness ◽  
Stellar Population ◽  
Population Synthesis ◽  
Stellar Population Synthesis ◽  
Major Merger ◽  
High Metallicity

AbstractWe have obtained deep g, r, and i-band Subaru and ultra-deep 3.6 μm IRAC images of parts of the multiply-wrapped stellar stream around the nearby edge-on galaxy NGC 5907. We have fitted the surface brightness measurements of the stream with FSPS stellar population synthesis models to derive the metallicity and age of the brightest parts of the stream. The resulting relatively high metallicity ([Fe/H] = −0.3) is consistent with a major merger scenario but a satellite accretion event cannot be ruled out.

scholarly journals MOCCA Survey Database: Extra Galactic Globular Clusters. I. Method and first results

2021 ◽  
Author(s):  
A Leveque ◽  
M Giersz ◽  
M Paolillo
Keyword(s):  
Globular Clusters ◽  
Surface Brightness ◽  
Velocity Dispersion ◽  
Structural Parameters ◽  
Dynamical Evolution ◽  
Central Surface ◽  
First Results ◽  
Preliminary Study ◽  
Galactic Globular Clusters ◽  
Gaia Dr2

Abstract Over the last few decades, exhaustive surveys of extra Galactic globular clusters (EGGCs) have become feasible. Only recently, limited kinematical information of globular clusters (GCs) were available through Gaia DR2 spectroscopy and also proper motions. On the other hand, simulations of GCs can provide detailed information about the dynamical evolution of the system. We present a preliminary study of EGGCs- properties for different dynamical evolutionary stages. We apply this study to 12 Gyr-old GCs simulated as part of the MOCCA Survey Database. Mimicking observational limits, we consider only a subssample of the models in the database, showing that it is possible to represent observed Milky Way GCs. In order to distinguish between different dynamical states of EGGCs, at least three structural parameters are necessary. The best distinction is achieved by considering the central parameters, those being observational core radius, central surface brightness, ratio between central and half-mass velocity dispersion, or similarly considering the central color, the central V magnitude and the ratio between central and half-mass radius velocity dispersion, although such properties could be prohibitive with current technologies. A similar but less solid result is obtained considering the average properties at the half-light radius, perhaps accessible presently in the Local Group. Additionally, we mention that the color spread in EGGCs due to internal dynamical models, at fixed metallcity, could be just as important due to the spread in metallicity.

scholarly journals Colour (≈Age?) Gradients in Spiral Galaxies

1996 ◽  
Vol 171 ◽  
pp. 358-358
Author(s):  
Roelof S. de Jong
Keyword(s):  
Surface Brightness ◽  
Stellar Population ◽  
Spiral Galaxies ◽  
List Type ◽  
Type Number ◽  
Population Synthesis ◽  
Early Type ◽  
Stellar Population Synthesis ◽  
Colour Distribution ◽  
Best Fit

A sample of 86 galaxies was imaged in the B, V, R, I, H and K passbands to study their light and colour distribution as function of radius (de Jong & van der Kruit 1994). The radial colour gradients were compared with new dust models, which included both absorption and scattering, and with the stellar population synthesis models of Bruzual & Chariot (1993) and Worthey (1994). By requiring that the models had to fit all six passband photometry at the same time, the relative effects of dust, stellar age and stellar metallicity could be seperated (de Jong 1995a, 1995b). The main results from this investigation are: –All galaxies become bluer with increasing radius. The colour at each radius correlates strongly with the average surface brightness at that radius, with Hubble type being an additional effect. Late type galaxies are bluer at the same surface brightness than early type galaxies.–The reddening profiles predicted by the dust models are incompatible with the data when all colours have to be fitted at the same time. Dust cannot be the major cause of the colour gradients.–The population synthesis models by Worthey (1994) indicate that the colour gradients cannot be caused by metallicity gradients alone.–The best fit to the data is reached in a model where the colour gradients are mainly caused by an age gradient across the disk, with an additional metallicity gradient to explain the very red central colours. The colours of galaxies of type later than Sc indicate that they have in general a lower metallicity at all radii than the earlier types.

Mid-IR colors and surface brightness fluctuations as tracers of stellar mass-loss in the TP-AGB

2018 ◽  
Vol 14 (S343) ◽  
pp. 411-412
Author(s):  
Rosa A. González-Lópezlira
Keyword(s):  
Mass Loss ◽  
Surface Brightness ◽  
Stellar Population ◽  
Mass Loss Rate ◽  
Agb Stars ◽  
Population Synthesis ◽  
Stellar Population Synthesis ◽  
Surface Brightness Fluctuations ◽  
Single Burst ◽  
Brightness Fluctuation

AbstractI present integrated colors and surface brightness fluctuation magnitudes in the mid-IR, derived from stellar population synthesis models that include the effects of the dusty envelopes around TP-AGB stars. The models are based on the Bruzual & Charlot CB* isochrones; they are single-burst, range in age from a few Myr to 14 Gyr, and comprise metallicities between Z = 0.0001 and Z = 0.04. I compare these models to mid-IR data of AGB stars and star clusters in the Magellanic Clouds, and study the effects of varying self-consistently the mass-loss rate, the stellar parameters, and the output spectra of the stars plus their dusty envelopes.

scholarly journals The Globular Cluster System of NGC 1316

2002 ◽  
Vol 207 ◽  
pp. 321-323
Author(s):  
Matías Gómez ◽  
Tom Richtler ◽  
Leopoldo Infante ◽  
Georg Drenkhahn
Keyword(s):  
Globular Cluster ◽  
Stellar Population ◽  
Cluster System ◽  
Angular Distributions ◽  
Population Synthesis ◽  
Stellar Population Synthesis ◽  
The Galaxy ◽  
Specific Frequency ◽  
Globular Cluster System ◽  
Fornax Cluster

We have studied the Globular Cluster System of the merger galaxy NGC 1316 in Fornax, using CCD BV I photometry. Dividing the sample into red (presumably metal-rich) and blue (metal-poor) subpopulations at B - I = 1.75, we find that they follow strikingly different angular distributions. The red clusters show a strong correlation with the galaxy elongation, but the blue ones are circularly distributed. An astonishingly low specific frequency for NGC 1316 of only SN = 0.9±0.2 is derived, which confirms with a larger field a previous finding by Grillmair et al. (1999). Assuming a “normal” SN of ∼ 4 for early-type galaxies, we use stellar population synthesis models to estimate the merger age to about 2 Gyr, if an intermediate-age population were to explain the low SN we observe. By fitting t5 functions to the Globular Cluster Luminosity Function (GCLF), we derive the following turnover magnitudes: and . They support that NGC 1316, in spite of its outlying location, is at the same distance as the core of the Fornax cluster.

Sign in / Sign up

Export Citation Format

Share Document