Evaporation, Tidal Disruption, and Orbital Decay of Star Clusters in a Galactic Halo

1996 ◽  
Vol 464 ◽  
pp. 765 ◽  
Author(s):  
Eugene R. Capriotti ◽  
Suzanne L. Hawley
Keyword(s):  
Galactic Halo ◽  
Star Clusters ◽  
Tidal Disruption ◽  
Orbital Decay

scholarly journals Are Pressure-Confined Clouds in Galactic Halos Possible Models of Lyman Alpha Clouds?

1999 ◽  
Vol 186 ◽  
pp. 481-481
Author(s):  
Keiko Miyahata ◽  
Satoru Ikeuchi
Keyword(s):  
Galactic Halo ◽  
Observational Constraints ◽  
Galactic Halos ◽  
Tidal Disruption ◽  
Lyman Alpha ◽  
Hot Gas ◽  
General Stability ◽  
Luminous Galaxies ◽  
Two Component ◽  
The Stability

Our understanding of the Lyα forest has changed considerably following observations by HST and Keck. Lyα clouds at low redshifts (z < 1.7) observed by HST showed two unexpected features: Lanzetta et al. (1995) found that most luminous galaxies at such redshifts produce Lyα absorptions at mean impact parameter ~160h−1kpc, and established the association between Lyα clouds and galaxies. Ulmer (1996) pointed out the strong clustering of Lyα clouds in this redshift range. Motivated by the above, we propose a two-component protogalaxy model for the Lyα clouds based upon our previous work (Miyahata & Ikeuchi 1995). In our model, the Lyα clouds are stable cold clouds confined by the pressure of ambient hot gas in a galactic halo. We determine the properties of these cold clouds and hot gas on the basis of theoretical and observational constraints. We take into account the stability of a cold cloud in the galactic halo in addition to the general stability conditions in a two-component medium (e.g. Ikeuchi & Ostriker 1986), and compare the derived quantities of Lyα clouds in the galactic halo and in the intergalactic medium at both high and low redshifts. We conclude that the ciondition that a cloud is stable against both evaporation and tidal disruption by a hot galactic halo is very restrictive. In the most noteworthy example at z ~ 0.5, a pressure-confined, stable spherical Lyα cloud with NHI = 1014cm−2 cannot survive in the galactic halo, although much higher column density clouds of NHI = 1017cm−2 can. Miyahata & Ikeuchi (1997) discuss how these results constrain an alternative model for Lyα clouds associated with the galaxies observed by Lanzetta et al. (1995).

scholarly journals On the disc and halo of the milky way through a study of star clusters

2000 ◽  
pp. 47-50 ◽  
Author(s):  
M. Nagl
Keyword(s):  
Spatial Distribution ◽  
Milky Way ◽  
Galactic Halo ◽  
Star Clusters ◽  
Galactic Disc ◽  
Open Star Clusters ◽  
Open Star ◽  
The Subject

The subject is the metallicity and the correlation between the metallicity and spatial distribution of star clusters of the Milky Way. The open star clusters are confirmed as good indicators for the population of the galactic disc, whereas the globular ones are confirmed as good indicators in the case of the galactic halo.

scholarly journals Calibrating the binary black hole population in nuclear star clusters through tidal disruption events

2020 ◽  
Vol 500 (4) ◽  
pp. 4307-4318
Author(s):  
Giacomo Fragione ◽  
Rosalba Perna ◽  
Abraham Loeb
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
Star Clusters ◽  
Mass Function ◽  
Intermediate Mass ◽  
Tidal Disruption ◽  
Scientific Question ◽  
Binary Black Hole ◽  
The Masses ◽  
Optical Transient

ABSTRACT As the sensitivity of gravitational wave (GW) instruments improves and new networks start operating, hundreds of merging stellar-mass black holes (SBHs) and intermediate-mass black holes (IMBHs) are expected to be observed in the next few years. The origin and distribution of SBH and IMBH binaries in various dynamical environments is a fundamental scientific question in GW astronomy. In this paper, we discuss ways tidal disruption events (TDEs) may provide a unique electromagnetic window into the assembly and merger of binary SBHs and IMBHs in nuclear star clusters (NSCs). We discuss how the host NSC mass and density and the slope of the BH mass function set the orbital properties and the masses of the binaries that undergo a TDE. For typical NSC properties, we predict a TDE rate of ∼10−6–10−7 yr−1 per galaxy. The light curve of TDEs in NSCs could be interrupted and modulated by the companion BH on the orbital period of the binary. These should be readily detectable by optical transient surveys such as the Zwicky Transient Facility and LSST.

scholarly journals Chemical evolution of star clusters

2010 ◽  
Vol 368 (1913) ◽  
pp. 801-828 ◽  
Author(s):  
Jacco Th. van Loon
Keyword(s):  
Dark Matter ◽  
Chemical Evolution ◽  
Gravitational Potential ◽  
Globular Clusters ◽  
Galactic Halo ◽  
Dwarf Galaxies ◽  
Star Clusters ◽  
Galactic Bulge ◽  
Potential Wells ◽  
The Galaxy

I discuss the chemical evolution of star clusters, with emphasis on old Galactic globular clusters (GCs), in relation to their formation histories. GCs are clearly formed in a complex fashion, under markedly different conditions from any younger clusters presently known. Those special conditions must be linked to the early formation epoch of the Galaxy and must not have occurred since. While a link to the formation of GCs in dwarf galaxies has been suggested, present-day dwarf galaxies are not representative of the gravitational potential wells within which the GCs formed. Instead, a formation deep within the proto-Galaxy or within dark-matter mini-haloes might be favoured. Not all GCs may have formed and evolved similarly. In particular, we may need to distinguish Galactic Halo from Galactic Bulge clusters.

Orbital Decay and Tidal Disruption of a Star Cluster: Analytical Calculation

2003 ◽  
Vol 585 (1) ◽  
pp. 250-255 ◽  
Author(s):  
Hideaki Mouri ◽  
Yoshiaki Taniguchi
Keyword(s):  
Analytical Calculation ◽  
Star Cluster ◽  
Tidal Disruption ◽  
Orbital Decay

scholarly journals A Search for Tidal Stellar Debris from the Magellanic Clouds: Survey Results from the First Two Years

1999 ◽  
Vol 190 ◽  
pp. 508-510 ◽  
Author(s):  
S. R. Majewski ◽  
J. C. Ostheimer ◽  
W. E. Kunkel ◽  
K. V. Johnston ◽  
R. J. Patterson ◽  
...  
Keyword(s):  
Globular Clusters ◽  
Main Sequence ◽  
Galactic Halo ◽  
Large Magellanic Cloud ◽  
Main Sequence Stars ◽  
Tidal Disruption ◽  
Negative Results ◽  
Ram Pressure ◽  
Survey Results ◽  
Magellanic Stream

An important discriminant between leading models for the origin of the Magellanic Stream is the presence of a stellar counterpart to the HI gas stream: ram pressure stripping of gas by a putative hot Galactic halo would act only on Magellanic gas while gravitational tidal stripping would act on both gas and stars. Several previous attempts to find tidal stellar debris have failed to find carbon stars, A stars, or other main sequence stars in the Magellanic Stream (Mathewson et al. 1979; Recillas-Cruz 1982; Brück & Hawkins 1983; Guhathakurta & Lin 1999). However, there has long been a suggestion (Kunkel 1979; Lynden-Bell 1982) of a possible Magellanic association of satellite galaxies and globular clusters that have similar orbits and may derive from the break up of a greater Magellanic galaxy (Lynden-Bell & Lynden-Bell 1995; Majewski et al. 1997). Recent models (Moore & Davis 1994; Johnston 1998) of the tidal disruption of Large Magellanic Cloud (LMC)-like systems indicate a wide dispersal of debris, much wider than the rather confined HI stream, so that the contrast of tidal debris against the Galactic fore/background would be low. If true, this could explain some of the previous negative results for tidal debris searches.

scholarly journals Extragalactic Star Clusters: Speculations on the Future

2002 ◽  
Vol 207 ◽  
pp. 745-754 ◽  
Author(s):  
J. S. Gallagher ◽  
E. K. Grebel
Keyword(s):  
Adaptive Optics ◽  
Massive Star ◽  
Angular Resolution ◽  
Star Clusters ◽  
Tidal Disruption ◽  
Model Predictions ◽  
The Future ◽  
Galactic Clusters ◽  
Resolution Imaging ◽  
Motion Measurements

We discuss the future possibilities for extragalactic star cluster research with the expected new ground-based and space-based telescopes and instrumentation. Significant gains are expected due to improved angular resolution, sensitivity, and area coverage particularly in the infrared and radio, accompanied by progress in evolutionary and dynamical modelling. Improvements in angular resolution are anticipated, especially through new adaptive optics systems (e.g., Keck, Gemini, VLT), and interferometry (e.g., Keck, VLT, LBT, ALMA, SMA, SkA), and space instrumentation (e.g., Chandra, NGST), enabling studies even of deeply embedded, forming extragalactic star clusters. Tidal disruption of Galactic clusters becomes observable through wide-area surveys such as the SDSS, VISTA, PRIME, including proper motion measurements through high-resolution imaging (e.g., HST, LBT, SIM, GAIA). Sensitive new optical and infrared spectrographs (e.g., HET, SALT, GranTeCan, Magellan, Keck, VLT, CELT, OWL, NGST) will push kinematic and abundance studies to new limits, allowing us detailed comparisons with model predictions. One important wavelength range for the study of young, massive star clusters, the far UV, appears to be neglected by future planned instrumentation.

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