scholarly journals The Evolution of Tidal Debris

2004 ◽  
Vol 217 ◽  
pp. 390-399 ◽  
Author(s):  
J. Christopher Mihos

Galaxy interactions expel a significant amount of stars and gas into the surrounding environment. I review the formation and evolution of the tidal debris spawned during these collisions, and describe how this evolution depends on the large scale environment in which the galaxies live. In addition to acting as a long-lived tracer of the interaction history of galaxies, the evolution of this material - on both large scales and small - has important ramifications for galactic recycling processes, the feeding of the intracluster light and intracluster medium within galaxy clusters, and the delayed formation of galactic disks and dwarf galaxies.

1998 ◽  
Vol 11 (1) ◽  
pp. 111-112
Author(s):  
Ulrich Lindner ◽  
Klaus J. Fricke ◽  
Jaan Einasto ◽  
Maret Einasto

Generally the density of the environment is important for the formation and evolution of galaxies: bright elliptical galaxies reside in the centers of galaxy clusters, whereas late type galaxies preferentially populate small groups, filaments or the outskirts of rich clusters of galaxies. Furthermore, fainter galaxies define smaller voids than bright galaxies. Our investigation of void catalogues in the Northern Local Void region shows that large voids are interlaced by systems of faint galaxies dividing them into smaller subvoids (Lindner et al., 1995). This void hierarchy is an important property of the Large Scale Structure in the nearby Universe and can help to solve problems concerning the distribution of dwarf galaxies and BCDGs.


2016 ◽  
Vol 11 (S321) ◽  
pp. 336-338
Author(s):  
E. Pompei ◽  
C. Adami ◽  

AbstractIntracluster light is contributed by both stars and gas and it is an important tracer of the interaction history of galaxies within a cluster. We present here the results obtained from MUSE observations of an intermediate redshift (z~ 0.5) cluster taken from the XXL survey and we conclude that the most plausible process responsible for the observed amount of ICL is ram pressure stripping.


2004 ◽  
Vol 217 ◽  
pp. 70-76
Author(s):  
Michael D. Gregg ◽  
Michael J. West

Gravitational interactions in rich clusters can strip material from the outer parts of galaxies or even completely disrupt entire systems, giving rise to large scale, low surface brightness ghostly features stretching across intergalactic space. The nearby Coma and Centaurus clusters both have striking examples of galaxy ghosts, in the form of 100 kpc-long plumes of intergalactic debris. By searching HST archival images, we have found numerous other examples of galaxy ghosts in rich clusters at low redshift, evidence that galaxy destruction and recycling are ubiquitous, important in cluster formation and evolution, and continue to mold clusters at the present epoch. Many ghosts appear in X-ray bright clusters, perhaps signaling a connection with energetic subcluster mergers.The fate of such material has important ramifications for cluster evolution. Our new HST WFPC2 V & I images of a portion of the Centaurus plume reveal that it contains an excess of discrete objects with −12 < MV < −6, consistent with being globular clusters or smaller dwarf galaxies. This tidally liberated material is being recycled directly into the intracluster population of stars, dwarf galaxies, globular clusters, and gas, which may have been built largely from a multitude of similar events over the life of the cluster.


2012 ◽  
Vol 2012 ◽  
pp. 1-24 ◽  
Author(s):  
Myriam Gitti ◽  
Fabrizio Brighenti ◽  
Brian R. McNamara

The current generation of flagship X-ray missions,ChandraandXMM-Newton, has changed our understanding of the so-called “cool-core” galaxy clusters and groups. Instead of the initial idea that the thermal gas is cooling and flowing toward the center, the new picture envisages a complex dynamical evolution of the intracluster medium (ICM) regulated by the radiative cooling and the nongravitational heating from the active galactic nucleus (AGN). Understanding the physics of the hot gas and its interplay with the relativistic plasma ejected by the AGN is key for understanding the growth and evolution of galaxies and their central black holes, the history of star formation, and the formation of large-scale structures. It has thus become clear that the feedback from the central black hole must be taken into account in any model of galaxy evolution. In this paper, we draw a qualitative picture of the current knowledge of the effects of the AGN feedback on the ICM by summarizing the recent results in this field.


2010 ◽  
Vol 2010 ◽  
pp. 1-5 ◽  
Author(s):  
Kentaro Nagamine

We examine the past and current work on the star formation (SF) histories of dwarf galaxies in cosmological hydrodynamic simulations. The results obtained from different numerical methods are still somewhat mixed, but the differences are understandable if we consider the numerical and resolution effects. It remains a challenge to simulate the episodic nature of SF history in dwarf galaxies at late times within the cosmological context of a cold dark matter model. More work is needed to solve the mysteries of SF history of dwarf galaxies employing large-scale hydrodynamic simulations on the next generation of supercomputers.


2000 ◽  
Vol 175 ◽  
pp. 611-616
Author(s):  
A. E. Dudorov ◽  
R. E. Pudritz

AbstractAn investigation of the formation and evolution of Be stars show that these stars could have dipolar fossil magnetic fields. This magnetic field should constrain the circumstellar magnetic disk and influence its dynamical features. For studying these effects we refine the alphamodel of accretion disks of Shakura and Sunyaev by incorporating into this model the evolution of large-scale magnetic fields. In the frame of our model we can investigate the rotational history of the star with the disk and the ionization and thermal properties of disks. We show in particular that in the magnetopause region a current sheet can form that can generate X-ray radiation.


2008 ◽  
Vol 4 (S254) ◽  
pp. 67-72 ◽  
Author(s):  
Shardha Jogee

AbstractHierarchical ΛCDM models provide a successful paradigm for the growth of dark matter on large scales, but they face important challenges in predicting how the baryonic components of galaxies evolve. I present constraints on two aspects of this evolution: (1) The interaction history of galaxies over the last 7 Gyr and the impact of interactions on their star formation properties, based on Jogeeet al. (2008a, b); (2) Constraints on the origin of bulges in hierarchical models and the challenge posed in accounting for galaxies with low bulge-to-total ratios, based on Weinzirl, Jogee, Khochar, Burkert, & Kormendy (2008, hereafter WJKBK08).


2014 ◽  
Vol 23 (10) ◽  
pp. 1430021
Author(s):  
Marc Davis

The history of cosmic structure goes back to the time of Einstein's youth, although few scientists actually thought of the problem of galaxy and cluster formation. The data and ideas were collected slowly as astronomers slowly realized the nature of the problem of large-scale structure. This paper will review several of the key episodes in the history of the field. Starting with the discovery of dark matter in the 30s, the CMBR discovery in the 1960s to the idea of an early episode of inflation in the 1980s, the field has had an acceleration of discovery. In the 80s it was realized that the initial conditions of the universe were specified by the cold dark matter (CDM). Now initial conditions for the formation of structure could be specified for any type of dark matter. With the advent of computing resources, highly nonlinear phases of galaxy formation could be simulated and scientists could ask whether cold dark matter was the correct theory, even on the scale of dwarf spheroidal galaxies, or do the properties of the dwarfs require a different type of dark matter? In an idiosyncratic list, we review several of the key events of the history of cosmic structure, including the first measurements of ξ(r), then the remarkable success of Λ CDM explanations of the large-scale universe. We next turn to velocity fields, the large-scale flow problem, a field which was so promising 20 years ago, and to the baryon acoustic oscillations, a field of remarkable promise today. We review the problem of dwarf galaxies and Lyman-α absorption systems, asking whether the evidence is pointing toward a major switch in our understanding of the nature of dark matter. Finally, we discuss flux anomalies in multiply-lensed systems, which set constraints on the number of dwarf galaxies associated with the lensing galaxy, a topic that is now very interesting since simulations have indicated there should be hundreds of dwarfs orbiting the Milky Way, rather than the 10 that are known. It is quite remarkable that many of the today's results are dependent on techniques first used by Einstein.


Galaxies ◽  
2018 ◽  
Vol 6 (4) ◽  
pp. 142 ◽  
Author(s):  
Valentina Vacca ◽  
Matteo Murgia ◽  
Federica Govoni ◽  
Torsten Enßlin ◽  
Niels Oppermann ◽  
...  

The formation and history of cosmic magnetism is still widely unknown. Significant progress can be made through the study of magnetic fields properties in the large-scale structure of the Universe: galaxy clusters, filaments, and voids of the cosmic web. A powerful tool to study magnetization of these environments is represented by radio observations of diffuse synchrotron sources and background or embedded radio galaxies. To draw a detailed picture of cosmic magnetism, high-quality data of these sources need to be used in conjunction with sophisticated tools of analysis.


Author(s):  
RIEN VAN DE WEYGAERT ◽  
ERWIN PLATEN

In this contribution we review and discuss several aspects of Cosmic Voids. Voids are a major component of the large scale distribution of matter and galaxies in the Universe. Their instrumental importance for understanding the emergence of the Cosmic Web is clear. Their relatively simple shape and structure makes them into useful tools for extracting the value of a variety cosmic parameters, possibly including even that of the influence of dark energy. Perhaps most promising and challenging is the issue of the galaxies found within their realm. Not only does the pristine environment of voids provide a promising testing ground for assessing the role of environment on the formation and evolution of galaxies, the dearth of dwarf galaxies may even represent a serious challenge to the standard view of cosmic structure formation.


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