scholarly journals The effect of dark matter on stars at the Galactic center: The paradox of youth problem

2020 ◽  
Vol 29 (08) ◽  
pp. 2050052
Author(s):  
Ebrahim Hassani ◽  
Reza Pazhouhesh ◽  
Hossein Ebadi
Keyword(s):  
Black Hole ◽  
Dark Matter ◽  
Galactic Center ◽  
Young Stars ◽  
Evolutionary Models ◽  
Massive Black Hole ◽  
Physical Conditions ◽  
Dm Effect ◽  
Evolutionary Paths ◽  
Evolutionary Simulations

Stars that evolve near the Galactic massive black hole show strange behaviors. The spectroscopic features of these stars show that they must be old. But their luminosities are much higher than the amounts that are predicted by the current stellar evolutionary models, which means that they must be active and young stars. In fact, this group of stars shows signatures of old and young stars, simultaneously. This is a paradox known as the “paradox of youth problem” (PYP). Some people tried to solve the PYP without supposing dark matter (DM) effects on stars. But, in this work, we implemented Weakly Interacting Massive Particles (WIMPs) annihilation as a new source of energy inside such stars. This implementation is logical for stars that evolve at high DM density environments. The new source of energy causes stars to follow different evolutionary paths on the H-R diagram in comparison with classical stellar evolutionary models. Increasing DM density in stellar evolutionary simulations causes the deviations from the standard H-R diagrams becomes more pronounced. By investigating the effects of WIMPs density on stellar structures and evolutions, we concluded that by considering DM effects on stars at the Galactic center, it is possible to solve the PYP. In addition to DM effect, complete solutions to PYP must consider all extreme and unique physical conditions that are present near the Galactic massive black hole.

scholarly journals MONITORING STELLAR ORBITS AROUND THE MASSIVE BLACK HOLE IN THE GALACTIC CENTER

2009 ◽  
Vol 692 (2) ◽  
pp. 1075-1109 ◽  
Author(s):  
S. Gillessen ◽  
F. Eisenhauer ◽  
S. Trippe ◽  
T. Alexander ◽  
R. Genzel ◽  
...  
Keyword(s):  
Black Hole ◽  
Galactic Center ◽  
Massive Black Hole ◽  
Stellar Orbits

scholarly journals Cosmological black holes are not described by the Thakurta metric: LIGO-Virgo bounds on PBHs remain unchanged

2021 ◽  
Vol 81 (11) ◽  
Author(s):  
Gert Hütsi ◽  
Tomi Koivisto ◽  
Martti Raidal ◽  
Ville Vaskonen ◽  
Hardi Veermäe
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
Dark Matter ◽  
Compact Object ◽  
Compact Objects ◽  
Primordial Black Hole ◽  
Mass Growth ◽  
Black Hole Binaries ◽  
Physical Conditions ◽  
Accretion Physics

AbstractWe show that the physical conditions which induce the Thakurta metric, recently studied by Bœhm et al. in the context of time-dependent black hole masses, correspond to a single accreting compact object in the entire Universe filled with isotropic non-interacting dust. In such a case, accretion physics is not local but tied to the properties of the whole Universe. We show that radiation, primordial black holes or particle dark matter cannot produce the specific energy flux required for supporting the mass growth of the compact objects described by the Thakurta metric. In particular, this solution does not apply to black hole binaries. We conclude that compact dark matter candidates and their mass growth cannot be described by the Thakurta metric, and thus existing constraints on the primordial black hole abundance from the LIGO-Virgo and the CMB measurements remain valid.

scholarly journals 11.15. The effect of a central massive black hole on the gas fueling

1998 ◽  
Vol 184 ◽  
pp. 485-486
Author(s):  
H. Fukuda ◽  
A. Habe ◽  
K. Wada
Keyword(s):  
Black Hole ◽  
Numerical Simulations ◽  
Gravitational Potential ◽  
Galactic Center ◽  
The Self ◽  
Massive Black Hole ◽  
Nuclear Regions ◽  
Self Gravity ◽  
Lindblad Resonance ◽  
Inner Lindblad Resonance

Nuclear activities in galaxies, such as nuclear starbursts or AGNs, are supposed to be induced by gas fueling into nuclear regions of galaxies. Non-axisymmetric gravitational potential caused by a stellar bar is a convincing mechanism for triggering gas fueling (Phinney 1994). However, numerical simulations have shown that the bar can not force the gas to accrete toward the galactic center beyond the inner Lindblad resonance (ILR). As a mechanism to overcome the ILR barrier, the double barred structure (Friedli & Martinet 1993), or the self-gravity of gas (Wada & Habe 1992, 1995; Elmegreen 1994) are proposed.

Clarification of the formation process of the super massive black hole by Infrared astrometric satellite, Small-JASMINE

2017 ◽  
Vol 12 (S330) ◽  
pp. 360-361 ◽  
Author(s):  
Taihei Yano ◽  
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
Phase Space ◽  
Formation Process ◽  
Near Infrared ◽  
Galactic Center ◽  
Space Distribution ◽  
Massive Black Hole ◽  
Phase Space Distribution ◽  
Merging Process

AbstractSmall-JASMINE (hearafter SJ), infrared astrometric satellite, will measure the positions and the proper motions which are located around the Galactic center, by operating at near infrared wave-lengths. SJ will clarify the formation process of the super massive black hole (hearafter SMBH) at the Galactic center. In particular, SJ will determine whether the SMBH was formed by a sequential merging of multiple black holes. The clarification of this formation process of the SMBH will contribute to a better understanding of merging process of satellite galaxies into the Galaxy, which is suggested by the standard galaxy formation scenario. A numerical simulation (Tanikawa and Umemura, 2014) suggests that if the SMBH was formed by the merging process, then the dynamical friction caused by the black holes have influenced the phase space distribution of stars. The phase space distribution measured by SJ will make it possible to determine the occurrences of the merging process.

Orbital In-spiral into a Massive Black Hole in a Galactic Center

2003 ◽  
Vol 590 (1) ◽  
pp. L29-L32 ◽  
Author(s):  
Tal Alexander ◽  
Clovis Hopman
Keyword(s):  
Black Hole ◽  
Galactic Center ◽  
Massive Black Hole

scholarly journals The distance to the Galactic Center

2012 ◽  
Vol 8 (S289) ◽  
pp. 29-35 ◽  
Author(s):  
Stefan Gillessen ◽  
Frank Eisenhauer ◽  
Tobias K. Fritz ◽  
Oliver Pfuhl ◽  
Thomas Ott ◽  
...  
Keyword(s):  
Black Hole ◽  
Galactic Center ◽  
Distance Estimate ◽  
Massive Black Hole ◽  
Geometric Distance ◽  
Stellar Orbits ◽  
Fundamental Parameters ◽  
The Galaxy ◽  
Error Bars ◽  
Definition Of

AbstractOne of the Milky Way's fundamental parameters is the distance of the Sun from the Galactic Center, R0. This article reviews the various ways of estimating R0, placing special emphasis on methods that have become possible recently. In particular, we focus on the geometric distance estimate made possible thanks to observations of individual stellar orbits around the massive black hole at the center of the Galaxy. The specific issues of concern there are the degeneracies with other parameters, most importantly the mass of the black hole and the definition of the reference frame. The current uncertainty is nevertheless only a few percent, with error bars shrinking every year.

scholarly journals Star Cluster Migration Near the Galactic Center

2009 ◽  
Vol 5 (S267) ◽  
pp. 329-329
Author(s):  
Michiko Fujii ◽  
Masaki Iwasawa ◽  
Yoko Funato ◽  
Junichiro Makino
Keyword(s):  
Black Hole ◽  
Galactic Center ◽  
Star Clusters ◽  
Star Cluster ◽  
Young Stars ◽  
Intermediate Mass ◽  
Self Consistent

AbstractWe performed a self-consistent N-body simulation of star clusters in the Galactic center (GC), taking into account the collisions of stars and formation of an intermediate-mass black hole (IMBH). We find that if an IMBH forms in the cluster, it carries young stars to the GC by a 1:1 resonance.

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