scholarly journals The Entropy Production of Galaxies

2021 ◽  
Author(s):  
Michael C. Parker ◽  
Chris Jeynes
Keyword(s):  
Black Hole ◽  
Entropy Production ◽  
Spiral Galaxies ◽  
Lagrange Equation ◽  
Supermassive Black Hole ◽  
Virial Mass ◽  
Zero Entropy ◽  
Double Spiral ◽  
The Universe ◽  
Over Time

Double-spiral galaxies are common in the Universe. It is known that the logarithmic double spiral is a Maximum Entropy geometry and represents spiral galaxies well. It is also known that the virial mass of such a galaxy can be approximately determined from the entropy of its central supermassive black hole. But over time the black hole must accrete mass, and therefore the overall galactic entropy must increase. From the associated entropic Euler-Lagrange equation (forming the basis of the Principle of Least Exertion, and also enabling the application of Nöther’s theorem) we show that the galactic entropy production is a conserved quantity, and we derive an appropriate expression for the relativistic entropic Hamiltonian of an idealised spiral galaxy. We generalise Onsager’s celebrated expression for entropy production and demonstrate that galactic entropy production has two parts, one many orders of magnitude larger than the other, and where the smaller is comparable to the Hawking radiation of the central supermassive black hole. We conclude that galaxies cannot be isolated, since even idealised spiral galaxies have non-zero entropy production.

scholarly journals A Relativistic Entropic Hamiltonian–Lagrangian Approach to the Entropy Production of Spiral Galaxies in Hyperbolic Spacetime

Universe ◽  
2021 ◽  
Vol 7 (9) ◽  
pp. 325
Author(s):  
Michael C. Parker ◽  
Chris Jeynes
Keyword(s):  
Black Hole ◽  
Entropy Production ◽  
Spiral Galaxy ◽  
Spiral Galaxies ◽  
Lagrange Equation ◽  
Structural Features ◽  
The Other ◽  
High Entropy ◽  
Hyperbolic Spacetime ◽  
Double Spiral

Double-spiral galaxies are common in the Universe. It is known that the logarithmic double spiral is a Maximum Entropy geometry in hyperbolic (flat) spacetime that well represents an idealised spiral galaxy, with its central supermassive black hole (SMBH) entropy accounting for key galactic structural features including the stability and the double-armed geometry. Over time the central black hole must accrete mass, with the overall galactic entropy increasing: the galaxy is not at equilibrium. From the associated entropic Euler–Lagrange Equation (enabling the application of Noether’s theorem) we develop analytic expressions for the galactic entropy production of an idealised spiral galaxy showing that it is a conserved quantity, and we also derive an appropriate expression for its relativistic entropic Hamiltonian. We generalise Onsager’s celebrated expression for entropy production and demonstrate that galactic entropy production (entropy production corresponds to the intrinsic dissipation characteristics) is composed of two parts, one many orders of magnitude larger than the other: the smaller is comparable to the Hawking radiation of the central SMBH, while the other is comparable to the high entropy processes occurring within the accretion disks of real SMBHs. We conclude that galaxies cannot be isolated, since even idealised spiral galaxies intrinsically have a non-zero entropy production.

scholarly journals The Dark Matter Halo Density Profile, Spiral Arm Morphology, and Supermassive Black Hole Mass of M33

2011 ◽  
Vol 2011 ◽  
pp. 1-8 ◽  
Author(s):  
Marc S. Seigar
Keyword(s):  
Black Hole ◽  
Dark Matter ◽  
Density Profile ◽  
Pitch Angle ◽  
Rotation Curve ◽  
Dark Matter Halo ◽  
Black Hole Mass ◽  
Supermassive Black Hole ◽  
Virial Mass ◽  
Spiral Arm

We investigate the dark matter halo density profile of M33. We find that the HI rotation curve of M33 is best described by an NFW dark matter halo density profile model, with a halo concentration of and a virial mass of . We go on to use the NFW concentration of M33, along with the values derived for other galaxies (as found in the literature), to show that correlates with both spiral arm pitch angle and supermassive black hole mass.

scholarly journals Gas filaments of the cosmic web located around active galaxies in a protocluster

Science ◽  
2019 ◽  
Vol 366 (6461) ◽  
pp. 97-100 ◽  
Author(s):  
H. Umehata ◽  
M. Fumagalli ◽  
I. Smail ◽  
Y. Matsuda ◽  
A. M. Swinbank ◽  
...  
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
Star Formation ◽  
Ionizing Radiation ◽  
Rest Frame ◽  
Active Galaxies ◽  
Intergalactic Gas ◽  
Supermassive Black Hole ◽  
The Universe ◽  
Intense Star Formation

Cosmological simulations predict that the Universe contains a network of intergalactic gas filaments, within which galaxies form and evolve. However, the faintness of any emission from these filaments has limited tests of this prediction. We report the detection of rest-frame ultraviolet Lyman-α radiation from multiple filaments extending more than one megaparsec between galaxies within the SSA22 protocluster at a redshift of 3.1. Intense star formation and supermassive black-hole activity is occurring within the galaxies embedded in these structures, which are the likely sources of the elevated ionizing radiation powering the observed Lyman-α emission. Our observations map the gas in filamentary structures of the type thought to fuel the growth of galaxies and black holes in massive protoclusters.

Primordial black holes and the observable features of the universe

2015 ◽  
Vol 24 (13) ◽  
pp. 1545005 ◽  
Author(s):  
K. M. Belotsky ◽  
A. A. Kirillov ◽  
S. G. Rubin
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
Dark Matter ◽  
Galactic Center ◽  
Mass Range ◽  
Primordial Black Holes ◽  
Simultaneous Solution ◽  
Supermassive Black Hole ◽  
Range Distribution ◽  
The Universe

Here, we briefly discuss the possibility to solve simultaneously with primordial black holes (PBHs) the problems of dark matter (DM), reionization of the universe, origin of positron line from Galactic center and supermassive black hole (BH) in it. Discussed scenario can naturally lead to a multiple-peak broad-mass-range distribution of PBHs in mass, which is necessary for simultaneous solution of the problems.

scholarly journals Evolution of Merger Remnants with Supermassive Black Holes

2003 ◽  
Vol 208 ◽  
pp. 455-456
Author(s):  
Jeremy Tinker ◽  
Barbara Ryden
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
Numerical Simulations ◽  
Spiral Galaxies ◽  
Elliptical Galaxies ◽  
Supermassive Black Holes ◽  
Host Galaxies ◽  
Supermassive Black Hole

We present results of numerical simulations of mergers of spiral galaxies using GADGET (Springel, Yoshida, & White 2001). In three of these simulations one of the progenitor galaxies contained a central supermassive black hole (BH), as well as one simulation which did not contain a BH. The merger remnants were evolved to an age of ∼ 13 Gyr to examine the evolution of the shape of each merger remnant. The results of these simulations were compared to observations of elliptical galaxies, which show that older galaxies appear rounder than younger ones (Ryden, Forbes, & Terlevich 2001).We found that the simulations in which the BH mass was fixed throughout the evolution influence the shape of their host galaxies on timescales less than 3 Gyr. These simulations show little trend of shape with age beyond this time. In the simulations in which the BH mass increased linearly over the duration of the simulation, there is a significant evolution of the shape of the remnant throughout its lifetime, comparable to the observational trend.

scholarly journals Constraining astrophysical observables of galaxy and supermassive black hole binary mergers using pulsar timing arrays

2019 ◽  
Vol 488 (1) ◽  
pp. 401-418 ◽  
Author(s):  
Siyuan Chen ◽  
Alberto Sesana ◽  
Christopher J Conselice
Keyword(s):  
Black Hole ◽  
Mass Function ◽  
Host Galaxy ◽  
Supermassive Black Hole ◽  
Pulsar Timing ◽  
Upper Limits ◽  
Binary Mergers ◽  
Black Hole Binary ◽  
Merger Rate ◽  
The Universe

ABSTRACT We present an analytic model to describe the supermassive black hole binary (SMBHB) merger rate in the Universe with astrophysical observables: galaxy stellar mass function, pair fraction, merger time-scale, and black hole–host galaxy relations. We construct observational priors and compute the allowed range of the characteristic spectrum hc of the gravitational wave background (GWB) to be 10−16 < hc < 10−15 at a frequency of f = 1 yr−1. We exploit our parametrization to tackle the problem of astrophysical inference from pulsar timing array (PTA) observations. We simulate a series of upper limits and detections and use a nested sampling algorithm to explore the parameter space. Corroborating previous results, we find that the current PTA non-detection does not place significant constraints on any observables; however, either future upper limits or detections will significantly enhance our knowledge of the SMBHB population. If a GWB is not detected at a level of hc(f = 1 yr−1) = 10−17, our current understanding of galaxy and SMBHB mergers is disfavoured at a 5σ level, indicating a combination of severe binary stalling, overestimating of the SMBH–host galaxy relations, and extreme dynamical properties of merging SMBHBs. Conversely, future detections of a Square Kilometre Array (SKA)-type instrument will allow to constrain the normalization of the SMBHB merger rate in the Universe, the time between galaxy pairing and SMBHB merging, the normalization of the SMBH–host galaxy relations and the dynamical binary properties, including their eccentricity and density of stellar environment.

scholarly journals Tracing the relation between black holes and dark haloes

2004 ◽  
Vol 220 ◽  
pp. 317-318
Author(s):  
Pieter Buyle ◽  
Maarten Baes ◽  
Herwig Dejonghe
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
Galaxy Formation ◽  
Velocity Dispersion ◽  
Spiral Galaxies ◽  
Circular Velocity ◽  
Supermassive Black Hole ◽  
Galaxy Formation And Evolution ◽  
Formation And Evolution ◽  
Fisher Relation

We present new velocity dispersion measurements for a set of 12 spiral galaxies and use them to derive a more accurate υc – σ relation which holds for a wide morphological range of galaxies. Combined with the MBH – σ relation, this relation can be used as a tool to estimate supermassive black hole (SMBH) masses by means of the asymptotic circular velocity. Together with the Tully-Fisher relation, it serves as a constraint for galaxy formation and evolution models.

scholarly journals Solutions to the Puzzles of Quantum Gravity and General Theory of Quantum Gravity and Quantum Gravity of the Universe and General Black Hole

2021 ◽  
Author(s):  
C. Huang ◽  
Yong-Chang Huang ◽  
Xinfei Li
Keyword(s):  
Black Hole ◽  
Gravitational Field ◽  
General Theory ◽  
Quantum Gravity ◽  
Lagrange Equation ◽  
Field Theories ◽  
Canonical Momentum ◽  
Gravitational Fields ◽  
Whole Process ◽  
The Universe

This paper gives both the solutions to the puzzles of quantum gravity and a general theory of quantum gravity, further shows quantum gravity of the Universe and general black hole, and discovers their relations reflecting symmetric propertis of the standard nonlinear gravitational Lagrangian, which are not relevant to any concrete metric models. This paper concretely shows the general commutation relations of the general gravitational field operators and their zeroth, first, second and third style, respectively, of high order canonical momentum operators for the general nonlinear system of the standard gravitational Lagrangian, and then has finished all the four styles of the quantization of the standard gravity. No needing, as usual, to solve the Euler-Lagrange equation to complete the whole process of the quantization of the standard gravitational fields, namely, this paper novelly simplifies all the current quantization theories of the standard gravitational fields. So lots of the complex calculations of quantum gravitational field theories up to now can be omitted to make the physical picture clearer, simpler and more easily understanding. Therefore, the solutions to puzzles of quantum gravity are given. Consequently, this paper opens a door to study and give a general theory of the quantum gravitational field don't depending on any concrete metric models.

scholarly journals Thermodynamics of a Black Hole

2015 ◽  
Vol 48 ◽  
pp. 123-137
Author(s):  
K.A.I.L. Wijewardena Gamalath ◽  
N.S. Rajapakse
Keyword(s):  
Black Hole ◽  
Visible Region ◽  
Black Hole Entropy ◽  
Mass Variation ◽  
Schwarzschild Black Hole ◽  
Black Hole Evaporation ◽  
Time Variations ◽  
The Given ◽  
The Universe ◽  
Over Time

A simple model was setup to find the mass variation over time for a Schwarzschild black hole. The temperature and entropy of a black hole was obtained from the numerically solved mass variation and the time variations of the black hole thermodynamic parameters were simulated. The mass of a given black hole reduces rapidly. The time taken for a black hole to vanish increases in an increasing rate with the given initial mass of the black hole. The temperature of a black hole drastically increases at the final stage of the black hole evaporation. The colour attributed to that temperature was found to be in the visible region for a significant amount of time. The black hole entropy also drastically reduces with its mass and through Hawking radiation it is added to the rest of the universe.

scholarly journals AGN mass estimates in large spectroscopic surveys: the effect of host galaxy light

2018 ◽  
Vol 618 ◽  
pp. A127 ◽  
Author(s):  
Ludovica Varisco ◽  
Tullia Sbarrato ◽  
Giorgio Calderone ◽  
Massimo Dotti
Keyword(s):  
Black Hole ◽  
Spectroscopic Analysis ◽  
Host Galaxy ◽  
Host Galaxies ◽  
Analysis Software ◽  
Supermassive Black Hole ◽  
Virial Mass ◽  
Fitting In ◽  
Black Hole Masses ◽  
Line Fitting

Virial–based methods for estimating active supermassive black hole masses are now commonly used on extremely large spectroscopic quasar catalogs. Most spectral analyses, though, do not pay enough attention to the detailed continuum decomposition. To understand how this affects virial mass estimates, we test the influence of host galaxy light on them, along with a Balmer continuum component. A detailed fit with the new spectroscopic analysis software QSFIT demonstrates that the presence or absence of continuum components does not significantly affect the virial-based results for our sample. Taking a host galaxy component into consideration or not, instead, affects the emission line fitting in a more pronounced way at lower redshifts, where in fact we observe dimmer quasars and more visible host galaxies.

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