scholarly journals Ejection of High‐Velocity Stars from the Galactic Center by an Inspiraling Intermediate‐Mass Black Hole

2006 ◽  
Vol 653 (2) ◽  
pp. 1203-1209 ◽  
Author(s):  
Yuri Levin
Keyword(s):  
Black Hole ◽  
High Velocity ◽  
Galactic Center ◽  
Intermediate Mass

scholarly journals Intermediate-mass black holes in globular clusters: observations and simulations - Update

2015 ◽  
Vol 12 (S316) ◽  
pp. 240-245
Author(s):  
Nora Lützgendorf ◽  
Markus Kissler-Patig ◽  
Karl Gebhardt ◽  
Holger Baumgardt ◽  
Diederik Kruijssen ◽  
...  
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
Globular Clusters ◽  
Galactic Center ◽  
Early Stage ◽  
Life Time ◽  
Intermediate Mass ◽  
Software Environment ◽  
Integral Field ◽  
Intermediate Mass Black Holes

AbstractThe study of intermediate-mass black holes (IMBHs) is a young and promising field of research. If IMBH exist, they could explain the rapid growth of supermassive black holes by acting as seeds in the early stage of galaxy formation. Formed by runaway collisions of massive stars in young and dense stellar clusters, intermediate-mass black holes could still be present in the centers of globular clusters, today. We measured the inner kinematic profiles with integral-field spectroscopy for 10 Galactic globular cluster and determined masses or upper limits of central black holes. In combination with literature data we further studied the positions of our results on known black-hole scaling relations (such as M• − σ) and found a similar but flatter correlation for IMBHs. Applying cluster evolution codes, the change in the slope could be explained with the stellar mass loss occurring in clusters in a tidal field over its life time. Furthermore, we present results from several numerical simulations on the topic of IMBHs and integral field units (IFUs). N-body simulations were used to simulate IFU data cubes. For the specific case of NGC 6388 we simulated two different IFU techniques and found that velocity dispersion measurements from individual velocities are strongly biased towards lower values due to blends of neighbouring stars and background light. In addition, we use the Astrophysical Multipurpose Software Environment (AMUSE) to combine gravitational physics, stellar evolution and hydrodynamics to simulate the accretion of stellar winds onto a black hole. We find that the S-stars need to provide very strong winds in order to explain the accretion rate in the galactic center.

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.

scholarly journals The Fifth Candidate for an Intermediate-mass Black Hole in the Galactic Center

2020 ◽  
Vol 890 (2) ◽  
pp. 167
Author(s):  
Shunya Takekawa ◽  
Tomoharu Oka ◽  
Yuhei Iwata ◽  
Shiho Tsujimoto ◽  
Mariko Nomura
Keyword(s):  
Black Hole ◽  
Galactic Center ◽  
Intermediate Mass

scholarly journals Indication of Another Intermediate-mass Black Hole in the Galactic Center

2019 ◽  
Vol 871 (1) ◽  
pp. L1 ◽  
Author(s):  
Shunya Takekawa ◽  
Tomoharu Oka ◽  
Yuhei Iwata ◽  
Shiho Tsujimoto ◽  
Mariko Nomura
Keyword(s):  
Black Hole ◽  
Galactic Center ◽  
Intermediate Mass

scholarly journals Supernovae-generated high-velocity compact clouds

2018 ◽  
Vol 612 ◽  
pp. L9 ◽  
Author(s):  
A. Yalinewich ◽  
P. Beniamini
Keyword(s):  
Black Hole ◽  
High Velocity ◽  
Molecular Cloud ◽  
Supernova Remnant ◽  
Galactic Center ◽  
Supernova Explosion ◽  
Fine Tuning ◽  
X Rays ◽  
Dynamical Time ◽  
The Masses

Context. A previous study claimed the discovery of an intermediate-mass black hole (IMBH). This hypothetical black hole was invoked in order to explain the high-velocity dispersion in one of several dense molecular clouds near the Galactic center. The same study considered the possibility that this cloud was due to a supernova explosion, but disqualified this scenario because no X-rays were detected. Aims. We here check whether a supernova explosion could have produced that cloud, and whether this explanation is more likely than an IMBH. More specifically, we wish to determine whether a supernova inside a dense molecular cloud would emit in the X-rays. Methods. We have approached this problem from two different directions. First, we performed an analytic calculation to determine the cooling rate by thermal bremsstrahlung and compared this time to the lifetime of the cloud. Second, we estimated the creation rate of these dense clouds in the central molecular zone (CMZ) region near the Galactic center, where they were observed. Based on this rate, we can place lower bounds on the total mass of IMBHs and clouds and compare this to the masses of the components of the CMZ. Results. We find that the cooling time of the supernova remnant inside a molecular cloud is shorter than its dynamical time. This means that the temperature in such a remnant would be much lower than that of a typical supernova remnant. At such a low temperature, the remnant is not expected to emit in the X-rays. We also find that to explain the rate at which such dense clouds are created requires fine-tuning the number of IMBHs. Conclusions. We find the supernova model to be a more likely explanation for the formation of high-velocity compact clouds than an IMBH.

scholarly journals The methods for searching hypervelocity star candidates from the SDSS

2013 ◽  
Vol 9 (S298) ◽  
pp. 421-421
Author(s):  
Yinbi Li ◽  
Ali Luo ◽  
Gang Zhao ◽  
Youjun Lu
Keyword(s):  
Black Hole ◽  
Velocity Distribution ◽  
Radial Velocity ◽  
Binary Stars ◽  
High Velocity ◽  
Main Sequence ◽  
Galactic Center ◽  
Main Sequence Stars ◽  
Massive Black Hole ◽  
Stellar Spectra

AbstractHyper-velocity stars are believed to be ejected out from the Galactic center through dynamical interactions of (binary) stars with the central massive black hole(s). In this paper, we firstly select F and G type main sequence stars from about 370,000 stellar spectra of DR7. Then, we select 369 high velocity stars from main sequence samples using the radial velocity distribution. Finally, we find 13 possible unbound hyper-velocity star candidates from the 369 high velocity stars.

scholarly journals Signature of an Intermediate-Mass Black Hole in the Central Molecular Zone of Our Galaxy

2016 ◽  
Vol 11 (S322) ◽  
pp. 119-122
Author(s):  
Tomoharu Oka ◽  
Reiko Mizuno ◽  
Kodai Miura ◽  
Shunya Takekawa
Keyword(s):  
Black Hole ◽  
Radio Telescope ◽  
Velocity Gradient ◽  
High Velocity ◽  
Molecular Cloud ◽  
Compact Object ◽  
Major Axis ◽  
Intermediate Mass ◽  
Massive Object ◽  
Molecular Lines

AbstractThe high-velocity compact cloud CO–0.40–0.22 was mapped in 22 molecular lines with the NRO 45 m radio telescope and the ASTE 10 m telescope. The map of each detected line shows that this cloud has a compact appearance (d≃3 pc) and extremely broad velocity width (Δ V≃100 km s−1). The representative position–velocity map along the major axis shows that CO–0.40–0.22 consists of an intense region with a shallow velocity gradient and a less intense high-velocity wing. This kinematical structure can be attributed to a gravitational kick to the molecular cloud caused by an invisible compact object with a mass of ~105M⊙. Its compactness and the absence of a counterpart at other wavelengths suggest that this massive object is an intermediate-mass black hole.

scholarly journals Galactic Center IRS 13E: Colliding Stellar Winds or an Intermediate-mass Black Hole?

2020 ◽  
Vol 897 (2) ◽  
pp. 135 ◽  
Author(s):  
Zhenlin Zhu ◽  
Zhiyuan Li ◽  
Anna Ciurlo ◽  
Mark R. Morris ◽  
Mengfei Zhang ◽  
...  
Keyword(s):  
Black Hole ◽  
Galactic Center ◽  
Stellar Winds ◽  
Intermediate Mass

Intermediate‐Mass Black Hole(s) and Stellar Orbits in the Galactic Center

2005 ◽  
Vol 635 (1) ◽  
pp. 341-348 ◽  
Author(s):  
Yuri Levin ◽  
Alice Wu ◽  
Ed Thommes
Keyword(s):  
Black Hole ◽  
Galactic Center ◽  
Intermediate Mass ◽  
Stellar Orbits

scholarly journals Hypervelocity stars from star clusters hosting intermediate-mass black holes

2019 ◽  
Vol 489 (4) ◽  
pp. 4543-4556 ◽  
Author(s):  
Giacomo Fragione ◽  
Alessia Gualandris
Keyword(s):  
Black Hole ◽  
High Velocity ◽  
Globular Clusters ◽  
Galactic Centre ◽  
Galactic Latitude ◽  
Dark Halo ◽  
Intermediate Mass ◽  
Galactocentric Distance ◽  
Galactic Potential ◽  
The Galaxy

ABSTRACT Hypervelocity stars (HVSs) represent a unique population of stars in the Galaxy reflecting properties of the whole Galactic potential. Determining their origin is of fundamental importance to constrain the shape and mass of the dark halo. The leading scenario for the ejection of HVSs is an encounter with the supermassive black hole in the Galactic centre. However, new proper motions from the Gaia mission indicate that only the fastest HVSs can be traced back to the Galactic centre and the remaining stars originate in the disc or halo. In this paper, we study HVSs generated by encounters of stellar binaries with an intermediate-mass black hole (IMBH) in the core of a star cluster. For the first time, we model the effect of the cluster orbit in the Galactic potential on the observable properties of the ejected population. HVSs generated by this mechanism do not travel on radial orbits consistent with a Galactic centre origin, but rather point back to their parent cluster, thus providing observational evidence for the presence of an IMBH. We also model the ejection of high-velocity stars from the Galactic population of globular clusters, assuming that they all contain an IMBH, including the effects of the cluster’s orbit and propagation of the star in the Galactic potential up to detection. We find that high-velocity stars ejected by IMBHs have distinctive distributions in velocity, Galactocentric distance and Galactic latitude, which can be used to distinguish them from runaway stars and stars ejected from the Galactic Centre.

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