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Posted: Mon Feb 06, 2017 8:58 pm
by Shahram
Not so lumpy after all: modeling the depletion of dark matter subhalos by Milky Way-like galaxies

Shea Garrison-Kimmel, Andrew R. Wetzel, James S. Bullock, Philip F. Hopkins, Michael Boylan-Kolchin, Claude-Andre Faucher-Giguere, Dusan Keres, Eliot Quataert, Robyn E. Sanderson, Andrew S. Graus, Tyler Kelley

Specifically, we compare simulations of the same two halos run using (1) DM-only (DMO), (2) full baryonic physics, and (3) DM with an embedded disk potential grown to match the FIRE simulation. Relative to baryonic simulations, DMO simulations contain ∼2× as many subhalos within 100 kpc of halo center;

They behave dark matter particles and baryonic particles in the same way and just add a factor to mass.
they used a central disk and they put it in x-y plane orientation and in the center of halo at redshift 3.
For center of mass they consider a big particle at the center of halo, so they don't need to calculate its center of mass !
They don't consider the effect of halo on disk and they are just interested to effect of disk on halo. according their comparison the difference between dark matter only (DMO) in one side and baryonic FIRE simulation and their simulations are big. Generally disk destroys more subhalos, especially in closer distances.
They show baryonic effects are extremely important and central galaxy is responsible for roughly half of the necessary changes for this system,
They also believe that important effective parameter is disk mass. Orientation and shape are in second priority.

I think their results are not bad for us but we should take these result serious. ;)

Re: Papers

Posted: Sat Feb 11, 2017 9:53 am
by Shahram
This sounds exciting, I am reading it now:
Simulating galaxy formation with black hole driven thermal and kinetic feedback
Rainer Weinberger, Volker Springel, Lars Hernquist, Annalisa Pillepich, Federico Marinacci, Rüdiger Pakmor, Dylan Nelson, Shy Genel, Mark Vogelsberger, Jill Naiman, Paul Torrey


Re: Papers

Posted: Fri Feb 17, 2017 9:53 pm
by Shahram
Classical papers on galaxy formation

On The Fragmentation of Gas Clouds Into Galaxies And Stars - F. Hoyle
This 1953 paper by Hoyle is a beautiful approach to this problem. It is old but still useful.

Formation of Galaxies And Clusters Of Galaxies By Self-Similar Gravitational Condensation - By W. H. Press & P. Schechter - 1973

Galaxy Formation Through Hierarchical Clustering - S. D. M. White & C. S. Frank - 1991

To be continued ...

Re: Papers

Posted: Sat Mar 04, 2017 10:27 am
by jbailin
Single most important galaxy formation paper to read is:

White & Rees (1978)
Core condensation in heavy halos - A two-stage theory for galaxy formation and clustering

Re: Papers

Posted: Wed Mar 22, 2017 9:39 pm
by Shahram
Comparing semi-analytic particle tagging and hydrodynamical simulations of the Milky Way's stellar halo

Andrew P. Cooper , Shaun Cole , Carlos S. Frenk , Theo Le Bret , Andrew Pontzen

In this paper they compare their particle tagging method with hydrodynamic simulations (AqC-SPH).
In first step they only use hydrodynamic simulation and they also apply particle tagging method to this model and for r>10 kpc results agrees. for smaller r there is a mismatch but by considering accreted stars both results fit.
In next step they repeat this comparison for dark matter n-body simulation. They also pick two galaxies with different dynamical history and compare them together.
Big part of this paper is response to this paper by Jeremy Bailin et al:

Systematic Problems With Using Dark Matter Simulations to Model Stellar Halos
Jeremy Bailin, Eric F. Bell, Monica Valluri, Greg S. Stinson, Victor P. Debattista, H. M. P. Couchman, James Wadsley

Re: Papers

Posted: Sun Apr 02, 2017 10:30 pm
by Shahram
Review of this paper about depletion modeling:

(1.24 MiB) Downloaded 39 times

Re: Papers

Posted: Fri Jun 16, 2017 5:24 pm
by Shahram
The accreted stellar halo as a window on halo assembly in L* galaxies
Nicola C. Amorisco

Re: Papers

Posted: Mon Mar 05, 2018 7:26 pm
by Shahram
This is a nice review paper:

Small-Scale Challenges to the ΛCDM Paradigm
James S. Bullock and Michael Boylan-Kolchin