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In this work, two new axisymmetric models for the Galactic mass distribution are presented. Motivated by recent results, these two models include the contribution of a stellar thin disc and of a thick disc, as massive as the thin…

星系天体物理 · 物理学 2017-02-01 Ektoras Pouliasis , Paola Di Matteo , Misha Haywood

We measure the contribution of galaxy disks to the overall gravitational potential of 30 nearly face-on intermediate-to-late-type spirals from the DiskMass Survey. The central vertical velocity dispersion of the disk stars, sigma(z,R=0), is…

We present a MUSE and KMOS dynamical study 405 star-forming galaxies at redshift z=0.28-1.65 (median redshift z=0.84). Our sample are representative of star-forming, main-sequence galaxies, with star-formation rates of SFR=0.1-30Mo/yr and…

In a disc galaxy the distribution of azimuthal components of velocity is very skew. In the past this skewness has been modelled by superposed Gaussians. We use dynamical arguments to derive an analytic formula that can be fitted to observed…

星系天体物理 · 物理学 2015-05-30 Ralph Schoenrich , James Binney

[Abridged] One of the most outstanding problems related to numerical models of galaxy formation is the so-called ``angular momentum catastrophe''. We study the evolution of the angular momentum from z~0.6 to z=0 to further our understanding…

天体物理学 · 物理学 2009-11-13 M. Puech , F. Hammer , M. D. Lehnert , H. Flores

Throughout the Hubble time, gas makes its way from the intergalactic medium into galaxies fuelling their star formation and promoting their growth. One of the key properties of the accreting gas is its angular momentum, which has profound…

星系天体物理 · 物理学 2020-03-04 Filippo Fraternali , Gabriele Pezzulli

The circular velocities of the inner region of disk galaxies are predicted by standard physics but velocities beyond the stellar disks are not consistent with Newtonian physics if the material there is in stable circular orbits. However,…

星系天体物理 · 物理学 2023-09-19 Earl Schulz

The total specific angular momentum j of a galaxy disk is matched with that of its dark matter halo, but the distributions are different, in that there is a lack of both low- and high-j baryons with respect to the CDM predictions. I…

The Universe is pervaded by magnetic fields in different scales, although for simplicity, they are ignored in most cosmological simulations. In this paper, we use the TNG50, which is a large cosmological galaxy formation simulation that…

星系天体物理 · 物理学 2023-07-28 Mohammad Hosseinirad , Fatemeh Tabatabaei , Mojtaba Raouf , Mahmood Roshan

A sample of 22 spiral galaxy rotation curves, measured in the 21 cm line of neutral hydrogen, is considered in the context of Milgrom's modified dynamics (MOND). Combined with the previous highly selected sample of Begeman et al. (1990),…

天体物理学 · 物理学 2009-10-28 R. H. Sanders

We use non-radiative N-body/SPH simulations of structure formation in a LCDM cosmology to compare the angular momentum distributions of dark matter and gas in a large sample of halos. We show that the two components have identical spin…

天体物理学 · 物理学 2009-09-25 Frank C. van den Bosch , Tom Abel , Rupert A. C. Croft , Lars Hernquist , Simon D. M. White

The mass distribution of the Galactic disk is constructed from the terminal velocity curve and the mass discrepancy-acceleration relation. Mass models numerically quantifying the detailed surface density profiles are tabulated. For $R_0 =…

星系天体物理 · 物理学 2016-01-13 Stacy S. McGaugh

We quantify the stellar rotation of galaxies by computing the $\lambda_{R}$ parameter, a proxy for the stellar angular momentum in a sample of 106 galaxies with redshift 0.1 $<$ z $<$ 0.8 and stellar masses from $\sim$10$^{7.5}$ to…

Maximum disc decompositions of rotation curves place a dynamical upper limit to the mass attributable to stars in galaxies. The precise definition of this term, however, can be vague and varies in usage. We develop an algorithm to robustly…

星系天体物理 · 物理学 2018-07-31 Nathaniel Starkman , Stacy McGaugh , Federico Lelli , James Schombert

The disks of spiral galaxies are generally elliptical rather than circular. The distribution of ellipticities can be fit with a log-normal distribution. For a sample of 12,764 galaxies from the Sloan Digital Sky Survey Data Release 1 (SDSS…

天体物理学 · 物理学 2009-11-10 Barbara S. Ryden

HI-Selected galaxies obey a linear relationship between their maximum detected radius Rmax and rotational velocity. This result covers measurements in the optical, ultraviolet, and HI emission in galaxies spanning a factor of 30 in size and…

星系天体物理 · 物理学 2018-03-23 Gerhardt R. Meurer , Danail Obreschkow , O. Ivy Wong , Zheng Zheng , Fiona M. Audcent-Ross , D. J. Hanish

(Abridged) Specific angular momentum is one of the key parameters that control the evolution of galaxies. We derive the baryonic specific angular momentum of disc galaxies and study its relation with the dark matter specific angular…

Semi-analytic models of self-gravitating discs often approximate the angular momentum transport generated by the gravitational instability using the phenomenology of viscosity. This allows the employment of the standard viscous evolution…

太阳与恒星天体物理 · 物理学 2015-05-19 Duncan Forgan , Ken Rice , Peter Cossins , Giuseppe Lodato

The surface brightness distribution in the majority of stellar galactic discs falls off exponentially. Often what lies beyond such a stellar disc is the neutral hydrogen gas whose distribution also follows a nearly exponential profile at…

星系天体物理 · 物理学 2015-06-22 Kanak Saha , Chanda J. Jog

We explore the dependence of the ratio of a galaxy's circular velocity, Vcirc, to its central velocity dispersion, sigma_0, on morphology, or equivalently total light concentration. Such a dependence is expected if light traces the mass.…

天体物理学 · 物理学 2011-02-11 Stephane Courteau , Michael McDonald , Lawrence M. Widrow , Jon Holtzman