Destruction of Galaxies as a Cause of the Appearance of Stellar Streams

2021 ◽  
Vol 65 (11) ◽  
pp. 1085-1101
Author(s):  
A. V. Tutukov ◽  
S. V. Vereshchagin ◽  
M. D. Sizova
Keyword(s):  
Stellar Streams

scholarly journals On N-body simulations of globular cluster streams

2021 ◽  
Vol 504 (1) ◽  
pp. 648-653
Author(s):  
Nilanjan Banik ◽  
Jo Bovy
Keyword(s):  
Dark Matter ◽  
Cold Dark Matter ◽  
Analytical Models ◽  
Numerical Density ◽  
Stellar Streams ◽  
Small Scales ◽  
Order Of Magnitude ◽  
Low Mass ◽  
Stream Density ◽  
Tidal Streams

ABSTRACT Stellar tidal streams are sensitive tracers of the properties of the gravitational potential in which they orbit and detailed observations of their density structure can be used to place stringent constraints on fluctuations in the potential caused by, e.g. the expected populations of dark matter subhaloes in the standard cold dark matter (CDM) paradigm. Simulations of the evolution of stellar streams in live N-body haloes without low-mass dark matter subhaloes, however, indicate that streams exhibit significant perturbations on small scales even in the absence of substructure. Here, we demonstrate, using high-resolution N-body simulations combined with sophisticated semi-analytical and simple analytical models, that the mass resolutions of 104–$10^5\, \rm {M}_{\odot }$ commonly used to perform such simulations cause spurious stream density variations with a similar magnitude on large scales as those expected from a CDM-like subhalo population and an order of magnitude larger on small, yet observable, scales. We estimate that mass resolutions of ${\approx}100\, \rm {M}_{\odot }$ (${\approx}1\, \rm {M}_{\odot }$) are necessary for spurious, numerical density variations to be well below the CDM subhalo expectation on large (small) scales. That streams are sensitive to a simulation’s particle mass down to such small masses indicates that streams are sensitive to dark matter clustering down to these low masses if a significant fraction of the dark matter is clustered or concentrated in this way, for example, in MACHO models with masses of 10–$100\, \rm {M}_{\odot }$.

scholarly journals Chemical Abundances of Seven Outer Halo M31 Globular Clusters from the Pan-Andromeda Archaeological Survey

2016 ◽  
Vol 11 (S321) ◽  
pp. 10-12
Author(s):  
Charli M. Sakari
Keyword(s):  
Globular Clusters ◽  
Milky Way ◽  
Dwarf Galaxy ◽  
Large Magellanic Cloud ◽  
Archaeological Survey ◽  
Chemical Abundances ◽  
Light Spectra ◽  
Sigma Level ◽  
Stellar Streams ◽  
Detailed Chemical

AbstractObservations of stellar streams in M31’s outer halo suggest that M31 is actively accreting several dwarf galaxies and their globular clusters (GCs). Detailed abundances can chemically link clusters to their birth environments, establishing whether or not a GC has been accreted from a satellite dwarf galaxy. This talk presents the detailed chemical abundances of seven M31 outer halo GCs (with projected distances from M31 greater than 30 kpc), as derived from high-resolution integrated-light spectra taken with the Hobby Eberly Telescope. Five of these clusters were recently discovered in the Pan-Andromeda Archaeological Survey (PAndAS)—this talk presents the first determinations of integrated Fe, Na, Mg, Ca, Ti, Ni, Ba, and Eu abundances for these clusters. Four of the target clusters (PA06, PA53, PA54, and PA56) are metal-poor ([Fe/H] < -1.5), α-enhanced (though they are possibly less alpha-enhanced than Milky Way stars at the 1 sigma level), and show signs of star-to-star Na and Mg variations. The other three GCs (H10, H23, and PA17) are more metal-rich, with metallicities ranging from [Fe/H] = -1.4 to -0.9. While H23 is chemically similar to Milky Way field stars, Milky Way GCs, and other M31 clusters, H10 and PA17 have moderately-low [Ca/Fe], compared to Milky Way field stars and clusters. Additionally, PA17’s high [Mg/Ca] and [Ba/Eu] ratios are distinct from Milky Way stars, and are in better agreement with the stars and clusters in the Large Magellanic Cloud (LMC). None of the clusters studied here can be conclusively linked to any of the identified streams from PAndAS; however, based on their locations, kinematics, metallicities, and detailed abundances, the most metal-rich PAndAS clusters H23 and PA17 may be associated with the progenitor of the Giant Stellar Stream, H10 may be associated with the SW Cloud, and PA53 and PA56 may be associated with the Eastern Cloud.

scholarly journals Stellar Streams Discovered in the Dark Energy Survey

2018 ◽  
Vol 862 (2) ◽  
pp. 114 ◽  
Author(s):  
N. Shipp ◽  
A. Drlica-Wagner ◽  
E. Balbinot ◽  
P. Ferguson ◽  
D. Erkal ◽  
...  
Keyword(s):  
Dark Energy ◽  
Dark Energy Survey ◽  
Stellar Streams ◽  
Energy Survey

scholarly journals Search for Stellar Streams Based on Data from the RAVE5 and Gaia TGAS Catalogues

2018 ◽  
Vol 44 (3) ◽  
pp. 193-201
Author(s):  
A. T. Bajkova ◽  
V. V. Bobylev
Keyword(s):  
Stellar Streams

scholarly journals A comprehensive tool for the statistical comparison of Large Surveys to Models of the Galaxy

2013 ◽  
Vol 9 (S298) ◽  
pp. 92-97
Author(s):  
Andreas Ritter
Keyword(s):  
Radial Velocity ◽  
Statistical Methods ◽  
Large Data ◽  
Data Set ◽  
Statistical Comparison ◽  
Stellar Streams ◽  
The Galaxy ◽  
Comprehensive Comparison ◽  
Moving Groups ◽  
First Time

AbstractThe advent of large spectroscopic surveys of the Galaxy offers the possibility to compare Galactic models to actual measurements for the first time. I have developed a tool for the comprehensive comparison of any large data set to the predictions made by models of the Galaxy using sophisticated statistical methods, and to visualise the results for any given direction. This enables us to point out systematic differences between the model and the measurements, as well as to identify new (sub-)structures in the Galaxy. These results can then be used to improve the models, which in turn will allow us to find even more substructures like stellar streams, moving groups, or clusters. In this paper I show the potential of this tool by applying it to the RAdial Velocity Experiment (RAVE, Steinmetz 2003) and the Besançon model of the Galaxy Robin et al. 2003.

scholarly journals HUBBLE SPACE TELESCOPEPROPER MOTIONS OF INDIVIDUAL STARS IN STELLAR STREAMS: ORPHAN, SAGITTARIUS, LETHE, AND THE NEW “PARALLEL STREAM”

2017 ◽  
Vol 833 (2) ◽  
pp. 235 ◽  
Author(s):  
Sangmo Tony Sohn ◽  
Roeland P. van der Marel ◽  
Nitya Kallivayalil ◽  
Steven R. Majewski ◽  
Gurtina Besla ◽  
...  
Keyword(s):  
Individual Stars ◽  
Stellar Streams ◽  
Parallel Stream

scholarly journals Extended stellar systems in the solar neighborhood

2019 ◽  
Vol 622 ◽  
pp. L13 ◽  
Author(s):  
Stefan Meingast ◽  
João Alves ◽  
Verena Fürnkranz
Keyword(s):  
Wavelet Decomposition ◽  
Stellar Population ◽  
Main Sequence ◽  
Milky Way ◽  
Velocity Dispersion ◽  
Galactic Disk ◽  
Mass Function ◽  
Solar Neighborhood ◽  
Giant Stars ◽  
Stellar Streams

We report the discovery of a large, dynamically cold, coeval stellar stream that is currently traversing the immediate solar neighborhood at a distance of only 100 pc. The structure was identified in a wavelet decomposition of the 3D velocity space of all stars within 300 pc of the Sun. Its members form a highly elongated structure with a length of at least 400 pc, while its vertical extent measures only about 50 pc. Stars in the stream are not isotropically distributed but instead form two parallel lanes with individual local overdensities, that may correspond to a remnant core of a tidally disrupted cluster or OB association. Its members follow a very well-defined main sequence in the observational Hertzsprung–Russel diagram and also show a remarkably low 3D velocity dispersion of only 1.3 km s−1. These findings strongly suggest a common origin as a single coeval stellar population. An extrapolation of the present-day mass function indicates a total mass of at least 2000 M⊙, making it larger than most currently known clusters or associations in the solar neighborhood. We estimated the age of the stream to be around 1 Gyr based on a comparison with a set of isochrones and giant stars in our member selection and find a mean metallicity of [Fe/H] = −0.04. This structure may very well represent the Galactic disk counterpart to the prominent stellar streams observed in the Milky Way halo. As such, it constitutes a new valuable probe to constrain the Galaxy’s mass distribution.

scholarly journals Determining the Galactic Bar Parameters Based on the Hercules and Wolf 630 Stellar Streams

2016 ◽  
Vol 25 (4) ◽  
Author(s):  
A. T. Bajkova ◽  
V. V. Bobylev
Keyword(s):  
Stellar Streams

AbstractWe identified the four most significant features in the

Sign in / Sign up

Export Citation Format

Share Document