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We examine the circular velocity profiles of galaxies in {\Lambda}CDM cosmological hydrodynamical simulations from the EAGLE and LOCAL GROUPS projects and compare them with a compilation of observed rotation curves of galaxies spanning a…

[Abridged] We use data on massive galaxy clusters ($M_{\rm cluster} > 8 \times 10^{14} h^{-1} M_\odot$ within a comoving radius of $R_{\rm cluster} = 1.5 h^{-1}\Mpc$) in the redshift range $0.05 \lesssim z \lesssim 0.83$ to place…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-30 L. Campanelli , G. L. Fogli , T. Kahniashvili , A. Marrone , Bharat Ratra

In this work, we aim at providing a consistent analysis of the dust properties from metal-poor to metal-rich environments by linking them to fundamental galactic parameters. We consider two samples of galaxies: the Dwarf Galaxy Survey (DGS)…

We present initial results from a wide field photometric survey of the Fornax dwarf spheroidal (dSph) galaxy. The focus here is on a small overdensity of stars located approximately 17 arcmin (670 pc in projection) from the centre of…

We study the connection between the observed star formation rate-stellar mass (SFR-$M_*$) relation and the evolution of the stellar mass function (SMF) by means of a subhalo abundance matching technique coupled to merger trees extracted…

Astrophysics of Galaxies · Physics 2017-11-15 E. Contini , X. Kang , A. D. Romeo , Q. Xia , S. K. Yi

The $\Gamma$ growth model is an effective parameterization employed across various scientific disciplines and scales to depict growth. It has been demonstrated that the cosmic star formation rate density (CSFRD) can also be described…

The recently reported Cosmic Himalayas (CH) -- an extreme quasar overdensity at z~2 -- poses an apparent challenge to the Lambda CDM framework, with a reported significance of 16.9-sigma under Gaussian assumptions. Such an event appears…

Using the BSBM varying-alpha theory, with dark matter dominated by magnetic energy, and the spherical collapse model for cosmological structure formation, we have studied the effects of the dark-energy equation of state and the coupling of…

Astrophysics · Physics 2009-11-10 D. F. Mota , J. D. Barrow

We report on the detection of Main Sequence stars belonging to the recently identified Canis Major galaxy in a field located at ~ 4.2 deg from the center of the stellar system. With Main Sequence fitting we obtain a distance modulus…

Astrophysics · Physics 2009-11-10 M. Bellazzini , R. Ibata , L. Monaco , N. Martin , M. J. Irwin , G. F. Lewis

We use galaxy groups selected from the Sloan Digital Sky Survey (SDSS) together with mass models for individual groups to study the galaxy-galaxy lensing signals expected from galaxies of different luminosities and morphological types. We…

Under the commonly used spherical collapse model, we study how dark energy affects the growth of large scale structures of the Universe in the context of agegraphic dark energy models. The dynamics of the spherical collapse of dark matter…

General Relativity and Quantum Cosmology · Physics 2017-10-11 M. Rezaei , M. Malekjani

The mass function of cluster-size halos and their redshift distribution are computed for 12 distinct accelerating cosmological scenarios and confronted to the predictions of the conventional flat $\Lambda$CDM model. The comparison with…

Cosmology and Nongalactic Astrophysics · Physics 2010-10-27 S. Basilakos , M. Plionis , J. A. S. Lima

Predicting the star formation rate (SFR) in galaxies is crucial to understand their evolution and morphology. To do so requires a fine understanding of how dense structures of gas are created and collapse. In that, turbulence and gravity…

Astrophysics of Galaxies · Physics 2024-10-02 Noé Brucy , Patrick Hennebelle , Tine Colman , Ralf S. Klessen , Corentin Le Yhuelic

I calculate the mass function evolution in a $\Lambda$CDM model by means of the excursion set model and an improved version of the barrier shape obtained in Del Popolo & Gambera (1998), which implicitly takes account of the total angular…

Astrophysics · Physics 2008-11-26 A. Del Popolo

The epoch of galaxy formation provides an important additional test of cosmological theories. Cold-dark-matter (CDM) models with cosmological constant ($\Lambda$) are designed to account for the observed excess power in galaxy distribution,…

Astrophysics · Physics 2009-10-28 A. Kashlinsky , R. Jimenez

The correlation between [Mg/Fe] and galaxy mass found in elliptical galaxies sets a strong constraint on the duration of star formation. Furthermore, the colour-magnitude relation restricts the range of ages and metallicities of the stellar…

Astrophysics · Physics 2009-11-07 I. Ferreras , J. Silk

The long-standing challenge of creating a Milky Way-like disk galaxy from cosmological simulations has motivated significant developments in both numerical methods and physical models in recent years. We investigate these two fundamental…

Astrophysics of Galaxies · Physics 2017-01-25 Qirong Zhu , Yuexing Li

We use cosmological hydrodynamic simulations to investigate how inflows, star formation, and outflows govern the the gaseous and metal content of galaxies. In our simulations, galaxy metallicities are established by a balance between…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-27 Romeel Davé , Kristian Finlator , Benjamin D. Oppenheimer

We study the evolutionary and physical properties of evolved O stars in the Small Magellanic Cloud (SMC), with a special focus on their surface abundances to investigate the efficiency of rotational mixing as a function of age, rotation and…