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It has been proposed that quantum complexity is dual to the volume of the extremal surface, the action of the Wheeler-DeWitt patch, and the spacetime volume of the patch. Recently, a generalized volume-complexity observable was formulated…

High Energy Physics - Theory · Physics 2023-11-27 Xuanhua Wang , Ran Li , Jin Wang

I give analytic expressions for the relative number, luminosity, and mass density of disc galaxies as a function of surface brightness. These surface brightness distributions are asymmetric, with long tails to lower surface brightnesses.…

Astrophysics · Physics 2015-06-24 Stacy McGaugh

A new method is developed which permits the reconstruction of the surface-density distribution in the galactic disk of finite radius from an arbitrary smooth distribution of the angular velocity via two simple quadratures. The existence of…

Astrophysics · Physics 2009-11-07 N. R. Sibgatullin , A. A. Garcia , V. S. Manko

We have re-estimated the surface density of the Galactic disk in the solar neighborhood within $\pm$ 0.4 kpc of the Sun using parallaxes and proper motions of a kinematically and spatially unbiased sample of 1476 old bright red giant stars…

Astrophysics · Physics 2009-11-10 V. I. Korchagin , T. M. Girard , T. V. Borkova , D. I. Dinescu , W. F. van Altena

We estimate the parameters of the Kennicutt-Schmidt (KS) relationship, linking the star formation rate (Sigma_SFR) to the molecular gas surface density (Sigma_mol), in the STING sample of nearby disk galaxies using a hierarchical Bayesian…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-16 Rahul Shetty , Brandon C. Kelly , Nurur Rahman , Frank Bigiel , Alberto D. Bolatto , Paul C. Clark , Ralf S. Klessen , Lukas K. Konstandin

We use the SPARC (Spitzer Photometry & Accurate Rotation Curves) database to study the relation between the central surface density of stars Sstar and dynamical mass Sdyn in 135 disk galaxies (S0 to dIrr). We find that Sdyn correlates…

Astrophysics of Galaxies · Physics 2016-08-17 Federico Lelli , Stacy S. McGaugh , James M. Schombert , Marcel S. Pawlowski

It was recently discovered that the mean dark matter surface density within one dark halo scale length - the radius within which the volume density profile of dark matter remains approximately flat - is constant across a wide range of…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-14 Gianfranco Gentile , Benoit Famaey , HongSheng Zhao , Paolo Salucci

A scalar-tensor theory of gravity is formulated in which $G$ and particle masses are allowed to vary. The theory yields a globally static cosmological model with no evolutionary timescales, no cosmological coincidences, and no flatness and…

General Physics · Physics 2015-10-01 Meir Shimon

I derive a new MOND relation for pure-disc galaxies: The `dynamical' central surface density, $\Sigma^0_D$, deduced from the measured velocities, is a universal function of only the true, `baryonic' central surface density, $\Sigma^0_B$:…

Astrophysics of Galaxies · Physics 2016-09-28 Mordehai Milgrom

The concept of velocity dependent mass, relativistic mass, is examined and is found to be inconsistent with the geometrical formulation of special relativity. This is not a novel result; however, many continue to use this concept and some…

Physics Education · Physics 2007-05-23 Gary Oas

The recent findings of Romanowsky et al., of an ``unexpectedly'' small mass discrepancy within 5 effective radii in several elliptical galaxies, are not surprising in the context of MOND. As we show here, they are, in fact, in full…

Astrophysics · Physics 2009-11-10 Mordehai Milgrom , Robert H. Sanders

We comment on the macroscopic model for surface plasmons of H.-Y. Deng [New J. Phys. 21 (2019) 043055; arXiv:1712.06101] and a claim, based on energy conversion from charges to the electric field, that surface plasmons on metallic surfaces…

Optics · Physics 2020-05-11 Gino Wegner , Carsten Henkel

In a recent note (arXiv:1012.5069), the investigation performed by the present authors on the evolution of density fluctuations in an accelerated universe including matter creation was criticized. The criticism is based on the fact that the…

Cosmology and Nongalactic Astrophysics · Physics 2010-12-30 Alain de Roany , J. A. de Freitas Pacheco

We estimated the Galactic model parameters by means of a new approach based on the comparison of the observed space density functions per absolute magnitude interval with a unique density law for each population individually, and via the…

Astrophysics · Physics 2009-11-10 S. Karaali , S. Bilir , E. Hamzaoglu

The dark matter hypothesis, which is not called into question here, explains why typical rotation curves of spiral galaxies do not follow a Keplerian profile. It is however not sufficient in itself to explain why the whole matter…

Astrophysics of Galaxies · Physics 2019-06-13 Vincent Deledicque

The variation of the kinematical properties of the Galactic thick disk with Galactic height Z are studied by means of 412 red giants observed in the direction of the south Galactic pole up to 4.5 kpc from the plane. We confirm the non-null…

Astrophysics of Galaxies · Physics 2015-06-04 C. Moni Bidin , G. Carraro , R. A. Mendez

We revisit the classical $K_Z$ problem -- determination of the vertical force and implied total mass density distribution of the Milky Way disk -- for a wide range of Galactocentric radius and vertical height using chemically selected thin…

Astrophysics of Galaxies · Physics 2023-10-02 Xinlun Cheng , Borja Anguiano , Steven R. Majewski , Phil Arras

It seems necessary to suppress, at least partially, the formation of structure on subgalactic scales. As an alternative to warm or collisional dark matter, I postulate a condensate of massive bosons interacting via a repulsive interparticle…

Astrophysics · Physics 2009-10-31 Jeremy Goodman

We show that if dark matter in a typical galaxy is a degenerate Fermi gas, particles should have a mass of $\sim$ 1eV for the galaxy to be stable. While this is the mass range of the active neutrinos, they are not a dark matter candidate in…

Astrophysics of Galaxies · Physics 2018-11-05 Ahmad Borzou

A simple method to describe spatially dispersive metasurfaces is proposed where the angle-dependent surface susceptibilities are explicitly used to formulate the zero thickness sheet model of practical metasurface structures. It is shown…

Applied Physics · Physics 2021-08-17 João G. Nizer Rahmeier , Tom J. Smy , Jordan Dugan , Shulabh Gupta