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This paper presents a new framework for understanding the relationship between a galaxy and its circumgalactic medium (CGM). It focuses on how imbalances between heating and cooling cause either expansion or contraction of the CGM. It does…

Astrophysics of Galaxies · Physics 2024-06-13 G. M. Voit , V. Pandya , D. B. Fielding , G. L. Bryan , C. Carr , M. Donahue , B. D. Oppenheimer , R. S. Somerville

The standard procedure to explain the accelerated expansion of the Universe is to assume the existence of an exotic component with negative pressure, generically called dark energy. Here, we propose a new accelerating flat cosmology without…

Cosmology and Nongalactic Astrophysics · Physics 2025-02-21 P. W. R. Lima , J. A. S. Lima , J. F. Jesus

We carry out a comparison study on the bar structure in the Illustris-1 and TNG100 simulations. At $z=0$, 8.9\% of 1232 disc galaxies with stellar mass $>10^{10.5}M_{\odot}$ in Illustris-1 are barred, while the numbers are 55\% of 1269 in…

Astrophysics of Galaxies · Physics 2020-10-05 Ze-Bang Zhou , Weishan Zhu , Yang Wang , Long-Long Feng

Perhaps the deepest mystery of our accelerating Universe in expansion is the existence of a tiny and rigid cosmological constant, $\Lambda$. Its size is many orders of magnitude below the expected one in the standard model of particle…

General Relativity and Quantum Cosmology · Physics 2015-04-03 Joan Sola , Adria Gomez-Valent

We simulate the formation of a realistic disk galaxy within the hierarchical scenario of structure formation and study its internal properties to the present epoch. We compare results from a LambdaCDM simulation with a LambdaWDM (2keV)…

Astrophysics · Physics 2008-11-26 F. Governato , L. Mayer , J. Wadsley , J. P. Gardner , B. Willman , E. Hayashi , T. Quinn , J. Stadel , G. Lake

In this review we outline the major points of ab-initio cosmological models focusing on some galaxy evolution unresolved problems. In particular our knowledge of the star formation rate which leads galaxy evolution, i.e. luminosity, colors…

Astrophysics · Physics 2009-09-29 Paola Mazzei

The dynamical nature and formation mechanism(s) of galactic spiral arms remain long-standing problems in astrophysics. Most theoretical work is based on analytic calculations or idealised simulations, which has yielded several theories of…

Recent analysis \citep{McGaugh2016} of the SPARC galaxy sample found a surprisingly tight relation between the radial acceleration inferred from the rotation curves, and the acceleration due to the baryonic components of the disc. It has…

Astrophysics of Galaxies · Physics 2017-02-16 B. W. Keller , J. W. Wadsley

Current theories of dynamical friction on galactic bars are based either on linear perturbation theory, which is valid only in the fast limit where the bar changes its pattern speed rapidly, or on adiabatic theory, which is applicable only…

Astrophysics of Galaxies · Physics 2023-08-04 Rimpei Chiba

We test the idea that bar pattern speeds decrease with time owing to angular momentum exchange with a dark matter halo. If this process actually occurs, then the locations of the corotation resonance and other resonances should generally…

Astrophysics of Galaxies · Physics 2022-02-23 Yun Hee Lee , Myeong-Gu Park , Ho Seong Hwang , Hong Bae Ann , Haeun Chung , Taehyun Kim

We review some general properties of assembling galactic dark matter (DM) halos which have a direct effect on the baryon dynamics. Specifically, we focus on the mutual dynamical feedback between baryons and DM which influence disk formation…

Cosmology and Nongalactic Astrophysics · Physics 2009-02-18 Isaac Shlosman

Bars in spiral galaxies can weaken through gas inflow towards the center, and angular momentum transfer. Several bar episodes can follow one another in the life of the galaxy, if sufficient gas is accreted from the intergalactic medium to…

Astrophysics · Physics 2008-11-05 F. Combes

We present first results from three-dimensional hydrodynamic simulations of the high redshift formation of dwarf galaxies. The simulations use an Eulerian adaptive mesh refinement technique to follow the non-equilibrium chemistry of…

Astrophysics · Physics 2009-11-07 Konstantinos Tassis , Tom Abel , Greg L. Bryan , Michael L. Norman

Galactic rotation curves are a fundamental constraint for any cosmological model. We use controlled N-body simulations of galaxies to study the gravitational effect of baryons in a scenario with collisionless cold dark matter (CDM) versus…

Astrophysics of Galaxies · Physics 2017-04-19 Peter Creasey , Omid Sameie , Laura V. Sales , Hai-Bo Yu , Mark Vogelsberger , Jesús Zavala

It is well-established that strong bars rotating in dense halos generally slow down as they lose angular momentum to the halo through dynamical friction. Angular momentum exchanges between the bar and halo particles take place at…

Astrophysics · Physics 2009-11-13 J. A. Sellwood , Victor P. Debattista

We use cosmological hydrodynamic simulations to consistently compare the assembly of dwarf galaxies in both $\Lambda$ dominated, Cold (CDM) and Self--Interacting (SIDM) dark matter models. The SIDM model adopts a constant cross section of 2…

Cosmology and Nongalactic Astrophysics · Physics 2015-07-28 A. Bastidas Fry , F. Governato , A. Pontzen , T. Quinn , M. Tremmel , L. Anderson , H. Menon , A. M. Brooks , J. Wadsley

We compare the properties of galaxies that form in a cosmological simulation without strong feedback to observations at z=0. We confirm previous findings that models without strong feedback overproduce the observed galaxy baryonic mass…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-13 Dušan Kereš , Neal Katz , Romeel Dave , Mark Fardal , David H. Weinberg

For several decades it has been known that stellar bars in disc galaxies can be triggered by interactions, or by internal processes such as dynamical instabilities. In this work, we explore the differences between these two mechanisms using…

We use a large volume-limited sample of disk galaxies drawn from the Sloan Digital Sky Survey Data Release 7 to study the dependence of the bar fraction on the stellar-to-halo mass ratio, making use of a group catalog, we identify central…

Astrophysics of Galaxies · Physics 2015-07-09 Bernardo Cervantes Sodi , Cheng Li , Changbom Park

Cosmologies including continuous matter creation are able to reproduce the main properties of the standard $\Lambda$CDM model, in particular in cases where the particle and entropy production rates are equal. These specific models,…

General Relativity and Quantum Cosmology · Physics 2011-03-07 Alain de Roany , J. A. de Freitas Pacheco