scholarly journals POPULATION OF BLACK HOLES IN THE MILKY WAY AND IN THE MAGELLANIC CLOUDS

2013 ◽  
Vol 53 (A) ◽  
pp. 665-670
Author(s):  
Janusz Ziółkowski
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
Milky Way ◽  
Stellar Mass ◽  
Magellanic Clouds ◽  
Intermediate Mass ◽  
Different Types ◽  
The Galaxy

In this review, I will briefly discuss the different types of black hole (BH) populations (supermassive, intermediate mass and stellar mass BHs) both in the Galaxy and in the Magellanic Clouds and compare them with each other.

scholarly journals No evidence for intermediate-mass black holes in the globular clusters ω Cen and NGC 6624

2019 ◽  
Vol 488 (4) ◽  
pp. 5340-5351 ◽  
Author(s):  
H Baumgardt ◽  
C He ◽  
S M Sweet ◽  
M Drinkwater ◽  
A Sollima ◽  
...  
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
Globular Clusters ◽  
Surface Brightness ◽  
Velocity Dispersion ◽  
Stellar Mass ◽  
Main Sequence Stars ◽  
Intermediate Mass ◽  
Measured Velocity ◽  
Large Grid

ABSTRACT We compare the results of a large grid of N-body simulations with the surface brightness and velocity dispersion profiles of the globular clusters ω Cen and NGC 6624. Our models include clusters with varying stellar-mass black hole retention fractions and varying masses of a central intermediate-mass black hole (IMBH). We find that an $\sim 45\, 000$ M⊙ IMBH, whose presence has been suggested based on the measured velocity dispersion profile of ω Cen, predicts the existence of about 20 fast-moving, m > 0.5 M⊙, main-sequence stars with a (1D) velocity v > 60 km s−1 in the central 20 arcsec of ω Cen. However, no such star is present in the HST/ACS proper motion catalogue of Bellini et al. (2017), strongly ruling out the presence of a massive IMBH in the core of ω Cen. Instead, we find that all available data can be fitted by a model that contains 4.6 per cent of the mass of ω Cen in a centrally concentrated cluster of stellar-mass black holes. We show that this mass fraction in stellar-mass BHs is compatible with the predictions of stellar evolution models of massive stars. We also compare our grid of N-body simulations with NGC 6624, a cluster recently claimed to harbour a 20 000 M⊙ black hole based on timing observations of millisecond pulsars. However, we find that models with MIMBH > 1000 M⊙ IMBHs are incompatible with the observed velocity dispersion and surface brightness profile of NGC 6624, ruling out the presence of a massive IMBH in this cluster. Models without an IMBH provide again an excellent fit to NGC 6624.

scholarly journals The MEMO project: Combining all microlensing surveys to search for intermediate-mass Galactic black holes

2018 ◽  
Vol 618 ◽  
pp. L4 ◽  
Author(s):  
A. Mirhosseini ◽  
M. Moniez
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
Milky Way ◽  
Detection Efficiency ◽  
Large Magellanic Cloud ◽  
Detection Algorithm ◽  
Intermediate Mass ◽  
Detection Rates ◽  
Galactic Black Hole ◽  
The Individual

Aims. The microlensing surveys MACHO, EROS, MOA and OGLE (hereafter called MEMO) have searched for microlensing toward the Large Magellanic Cloud for a cumulated duration of 27 years. We study the potential of joining these databases to search for very massive objects, that produce microlensing events with a duration of several years. Methods. We identified the overlaps between the different catalogs and compiled their time coverage to identify common regions where a joint microlensing detection algorithm can operate. We extrapolated a conservative global microlensing detection efficiency based on simple hypotheses, and estimated detection rates for multi-year duration events. Results. Compared with the individual survey searches, we show that a combined search for long timescale microlensing should detect about ten more events caused by 100 M⊙ black holes if these objects have a major contribution to the Milky Way halo. Conclusions. Assuming that a common analysis is feasible, meaning that the difficulties that arise from using different passbands can be overcome, we show that the sensitivity of such an analysis might enable us to quantify the Galactic black hole component.

scholarly journals Be/X-Ray Binaries with Black Holes in the Galaxy and in the Magellanic Clouds

2014 ◽  
Vol 1 (1) ◽  
pp. 175-180 ◽  
Author(s):  
Janusz Ziolkowski
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
Neutron Star ◽  
Magellanic Clouds ◽  
X Ray ◽  
The Galaxy ◽  
X Ray Binaries ◽  
Successful Candidate

I will start with the statistics indicating that the objects named in the title of my talk are either non-existing or very elusive to detect (not a single such object is known against 119 known Be/neutron star X-ray binaries). After brief reviewing of the properties of Be/X-ray binaries I discuss several objects that were proposed as the long sought for candidates for Be/black hole X-ray binaries. After three unsuccessful candidates (LS I +61° 303, LS 5039 and MAXI J1836-194), a successful candidate (AGL J2241+4454/MWC 656) was finally, very recently, announced.

scholarly journals On the apparent lack of Be X-ray binaries with black holes in the galaxy and in the Magellanic Clouds

2010 ◽  
Vol 6 (S275) ◽  
pp. 329-330
Author(s):  
Janusz Ziółkowski ◽  
Krzysztof Belczyński
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
Neutron Star ◽  
Stellar Population ◽  
Magellanic Clouds ◽  
Population Synthesis ◽  
X Ray ◽  
Stellar Population Synthesis ◽  
The Galaxy ◽  
X Ray Binaries

AbstractIn the Galaxy there are 67 Be X-ray binaries known to-date. Out of those, 45 host a neutron star, and for the reminder the nature of a companion is not known. None, so far, is known to host a black hole. This disparity is referred to as a missing Be – black hole X-ray binary problem. The stellar population synthesis calculations following the formation of Be X-ray binaries (Belczyński & Ziółkowski 2009) predict that the ratio of the binaries with neutron stars to the ones with black holes is rather high FNS/BH ~ 30–50. A comparison of this ratio with the number of confirmed Be – neutron star X-ray binaries (45) indicates that the expected number of Be – black hole X-ray binaries is of the order of only ~0–2. This is entirely consistent with the observed Galactic sample. Therefore, there is no problem of the missing Be+BH X-Ray Binaries for the GalaxyIn the Magellanic Clouds there are 94 Be X-ray binaries known to-date. Out of those, 60 host a neutron star. Again, none hosts a black hole. The stellar population synthesis calculations carried out specifically for the Magellanic Clouds (Ziółkowski & Belczyński 2010) predict that the ratio of the Be X-ray binaries with neutron stars to the ones with black holes is only FNS/BH ~ 10. This value is rather too low, as it implies the expected number of Be+BH X-ray binaries of the order of ~6, while none is observed. We found, that to remove the discrepancy, one has to take into account a different history of the star formation rate in the Magellanic Clouds, with the respect to the Galaxy. New stellar population synthesis calculations are currently being carried out.

scholarly journals mocca-survey Database I: Binary black hole mergers from globular clusters with intermediate mass black holes

2020 ◽  
Vol 498 (3) ◽  
pp. 4287-4294
Author(s):  
Jongsuk Hong ◽  
Abbas Askar ◽  
Mirek Giersz ◽  
Arkadiusz Hypki ◽  
Suk-Jin Yoon
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
Gravitational Waves ◽  
Globular Clusters ◽  
Stellar Mass ◽  
Intermediate Mass ◽  
Binary Black Holes ◽  
Black Hole Binaries ◽  
Binary Black Hole ◽  
Intermediate Mass Black Holes

ABSTRACT The dynamical formation of black hole binaries in globular clusters that merge due to gravitational waves occurs more frequently in higher stellar density. Meanwhile, the probability to form intermediate mass black holes (IMBHs) also increases with the density. To explore the impact of the formation and growth of IMBHs on the population of stellar mass black hole binaries from globular clusters, we analyse the existing large survey of Monte Carlo globular cluster simulation data (mocca-survey Database I). We show that the number of binary black hole mergers agrees with the prediction based on clusters’ initial properties when the IMBH mass is not massive enough or the IMBH seed forms at a later time. However, binary black hole formation and subsequent merger events are significantly reduced compared to the prediction when the present-day IMBH mass is more massive than ${\sim}10^4\, \rm M_{\odot }$ or the present-day IMBH mass exceeds about 1 per cent of cluster’s initial total mass. By examining the maximum black hole mass in the system at the moment of black hole binary escaping, we find that ∼90 per cent of the merging binary black holes escape before the formation and growth of the IMBH. Furthermore, large fraction of stellar mass black holes are merged into the IMBH or escape as single black holes from globular clusters in cases of massive IMBHs, which can lead to the significant underpopulation of binary black holes merging with gravitational waves by a factor of 2 depending on the clusters’ initial distributions.

scholarly journals Origins of Stellar Mass Neutron Black Holes, Supermassive Dark Matter Black Holes and Universe Evolution

2021 ◽  
Author(s):  
Jae-Kwang Hwang
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
Dark Matter ◽  
Big Bang ◽  
Stellar Mass ◽  
Intermediate Mass ◽  
Milky Way Galaxy ◽  
Dark Matters ◽  
The Big Bang ◽  
Universe Evolution

The origins of the stellar mass neutron black holes and supermassive dark matter black holes without the singularities are reported based on the 4-D Euclidean space. The neutron black holes with the mass of mBH = 5 – 15 msun are made by the 6-quark merged states (N6q) of two neutrons with the mass (m(N6q) = 10 m(n)) of 9.4 GeV/c2 that gives the black hole mass gap of mBH = 3 – 5 msun. Also, the supermassive black holes with the mass of mSMBH = 106 – 1011 msun are made by the merged 3-D states (J(B1B2B3)3 particles) of the dark matters. The supermassive black hole at the center of the Milky way galaxy has the mass of mSMBH = 4.1 106 msun that is consistent with mSMBH = 2.08 - 6.23 106 msun calculated from the 3-D states (J(B1B2B3)3 particles) of the dark matters with the mass of m(J) = 1.95 1015 eV/c2. In other words, this supports the existence of the B1, B2 and B3 dark matters with the proposed masses. The first dark matter black hole (primary black hole) was created at the big bang. This first dark matter black hole decayed to the supermassive dark matter black holes through the secondary dark matter black holes that are explained by the merged states of the J(B1B2B3)3 particles. The universe evolution is closely connected to the decaying process of the dark matter black holes since the big bang. The dark matter cloud states are proposed at the intermediate mass black hole range of mIMBH = 102 – 105 msun. This can explain why the dark matter black holes are not observed at the intermediate mass black hole range of mIMBH = 102 – 105 msun.

Fossil SMBHs in the Milky Way Halo

2009 ◽  
Vol 5 (S267) ◽  
pp. 196-196
Author(s):  
Jillian Bellovary ◽  
Fabio Governato ◽  
Tom Quinn
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
Star Formation ◽  
Milky Way ◽  
Intermediate Mass ◽  
Massive Galaxies ◽  
Hierarchical Assembly ◽  
Supernova Feedback ◽  
Black Hole Candidates ◽  
Milky Way Halo

As galaxies assemble through hierarchical merging, some black holes grow to become the central black holes of massive galaxies; however, others may be stripped via interactions into regions of galaxies where they will remain quiescent. Such objects may be the source of observed off-nuclear intermediate-mass black hole candidates, as detected by Farrell et al. (2009). We use a cosmological N-body simulation of a disk-dominated galaxy (Vc = 140 km s−1, presented by Governato et al. 2009) to examine the formation and merging histories of seed black holes during hierarchical assembly. Our method incorporates star formation, supernova feedback, a physically motivated description of black hole seed creation, growth, and merging.

scholarly journals Origins of Stellar Mass Neutron Black Holes, Supermassive Dark Matter Black Holes and Universe Evolution

2021 ◽  
Author(s):  
Jae-Kwang Hwang
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
Dark Matter ◽  
Big Bang ◽  
Stellar Mass ◽  
Intermediate Mass ◽  
Milky Way Galaxy ◽  
Dark Matters ◽  
The Big Bang ◽  
Universe Evolution

The origins of the stellar mass neutron black holes and supermassive dark matter black holes without the singularities are reported based on the 4-D Euclidean space. The neutron black holes with the mass of mBH = 5 – 15 msun are made by the 6-quark merged states (N6q) of two neutrons with the mass (m(N6q) = 10 m(n)) of 9.4 GeV/c2 that gives the black hole mass gap of mBH = 3 – 5 msun. Also, the supermassive black holes with the mass of mSMBH = 106 – 1011 msun are made by the merged 3-D states (J(B1B2B3)3 particles) of the dark matters. The supermassive black hole at the center of the Milky way galaxy has the mass of mSMBH = 4.1 106 msun that is consistent with mSMBH = 2.08 - 6.23 106 msun calculated from the 3-D states (J(B1B2B3)3 particles) of the dark matters with the mass of m(J) = 1.95 1015 eV/c2. In other words, this supports the existence of the B1, B2 and B3 dark matters with the proposed masses. The first dark matter black hole (primary black hole) was created at the big bang. This first dark matter black hole decayed to the supermassive dark matter black holes through the secondary dark matter black holes that are explained by the merged states of the J(B1B2B3)3 particles. The universe evolution is closely connected to the decaying process of the dark matter black holes since the big bang. The dark matter cloud states are proposed at the intermediate mass black hole range of mIMBH = 102 – 105 msun. This can explain why the dark matter black holes are not observed at the intermediate mass black hole range of mIMBH = 102 – 105 msun.

6. How do you weigh a black hole?

2015 ◽  
Author(s):  
Katherine Blundell
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
Binary System ◽  
Stellar Mass ◽  
Infra Red ◽  
The Galaxy ◽  
Dynamic Techniques ◽  
The Masses ◽  
Similar Dynamic

Infra-red observations have been used by teams in California and Germany to measure the mass of the black hole at the centre of the Galaxy at just over 4 million times the mass of our Sun. ‘How do you weigh a black hole?’ shows that similar dynamic techniques can be used to measure the masses of the millions of black holes that pervade our Galaxy as stars and black holes are frequently found as pairs in a binary system. The smallest black hole that we can measure is a few times the mass of our Sun, but the heaviest stellar-mass black holes can exceed a hundred times the mass of our Sun.

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