TY  - JOUR
A1  - Gong, Chen Chris
A1  - Libeskind, Noam I.
A1  - Tempel, Elmo
A1  - Guo, Quan
A1  - Gottloeber, Stefan
A1  - Yepes, Gustavo
A1  - Wang, Peng
A1  - Sorce, Jenny
A1  - Pawlowski, Marcel
T1  - The origin of lopsided satellite galaxy distribution in galaxy pairs
JF  - Monthly notices of the Royal Astronomical Society
N2  - It is well known that satellite galaxies are not isotropically distributed among their host galaxies as suggested by most interpretations of the Λ cold dark matter (ΛCDM) model. One type of anisotropy recently detected in the Sloan Digital Sky Survey (and seen when examining the distribution of satellites in the Local Group and in the Centaurus group) is a tendency to be so-called lopsided. Namely, in pairs of galaxies (like Andromeda and the Milky Way) the satellites are more likely to inhabit the region in between the pair, rather than on opposing sides. Although recent studies found a similar set-up when comparing pairs of galaxies in ΛCDM simulations indicating that such a set-up is not inconsistent with ΛCDM, the origin has yet to be explained. Here we examine the origin of such lopsided set-ups by first identifying such distributions in pairs of galaxies in numerical cosmological simulations, and then tracking back the orbital trajectories of satellites (which at z = 0 display the effect). We report two main results: first, the lopsided distribution was stronger in the past and weakens towards z = 0. Secondly, the weakening of the signal is due to the interaction of satellite galaxies with the pair. Finally, we show that the z = 0 signal is driven primarily by satellites that are on first approach, who have yet to experience a ‘flyby’. This suggests that the signal seen in the observations is also dominated by dynamically young accretion events.
KW  - galaxies: evolution
KW  - galaxies: formation
KW  - galaxy: kinematics and dynamics
KW  - Local Group
KW  - dark matter
KW  - cosmology: theory
Y1  - 2019
U6  - https://doi.org/10.1093/mnras/stz1917
SN  - 0035-8711
SN  - 1365-2966
VL  - 488
IS  - 3
SP  - 3100
EP  - 3108
PB  - Oxford Univ. Press
CY  - Oxford
ER  - 
TY  - JOUR
A1  - Nuza, Sebastian E.
A1  - Parisi, Florencia
A1  - Scannapieco, Cecilia
A1  - Richter, Philipp
A1  - Gottloeber, Stefan
A1  - Steinmetz, Matthias
T1  - The distribution of gas in the Local Group from constrained cosmological simulations: the case for Andromeda and the Milky Way galaxies
JF  - Monthly notices of the Royal Astronomical Society
N2  - We study the gas distribution in the Milky Way and Andromeda using a constrained cosmological simulation of the Local Group (LG) within the context of the CLUES (Constrained Local UniversE Simulations) project. We analyse the properties of gas in the simulated galaxies at z = 0 for three different phases: 'cold', 'hot' and H i, and compare our results with observations. The amount of material in the hot halo (M-hot a parts per thousand 4-5 x 10(10) M-aS (TM)), and the cold (M-cold(r a parts per thousand(2) 10 kpc) a parts per thousand 10(8) M-aS (TM)) and H i components displays reasonable agreement with observations. We also compute the accretion/ejection rates together with the H i (radial and all-sky) covering fractions. The integrated H i accretion rate within r = 50 kpc gives similar to 0.2-0.3 M-aS (TM) yr(-1), i.e. close to that obtained from high-velocity clouds in the Milky Way. We find that the global accretion rate is dominated by hot material, although ionized gas with T a parts per thousand(2) 10(5) K can contribute significantly too. The net accretion rates of all material at the virial radii are 6-8 M-aS (TM) yr(-1). At z = 0, we find a significant gas excess between the two galaxies, as compared to any other direction, resulting from the overlap of their gaseous haloes. In our simulation, the gas excess first occurs at z similar to 1, as a result of the kinematical evolution of the LG.
KW  - methods: numerical
KW  - Galaxy: halo
KW  - intergalactic medium
KW  - Local Group
KW  - large-scale structure of Universe
Y1  - 2014
U6  - https://doi.org/10.1093/mnras/stu643
SN  - 0035-8711
SN  - 1365-2966
VL  - 441
IS  - 3
SP  - 2593
EP  - 2612
PB  - Oxford Univ. Press
CY  - Oxford
ER  -