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Non-standard formation processes of low-mass black holes

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Kumar, Shami ULiège
Promotor(s) : Cudell, Jean-René ULiège
Date of defense : 1-Jul-2019/2-Jul-2019 • Permalink : http://hdl.handle.net/2268.2/6992
Details
Title : Non-standard formation processes of low-mass black holes
Translated title : [fr] Processus de formation non-standarts de trous noirs de faible masse
Author : Kumar, Shami ULiège
Date of defense  : 1-Jul-2019/2-Jul-2019
Advisor(s) : Cudell, Jean-René ULiège
Committee's member(s) : Rauw, Grégor ULiège
Nazé, Yaël ULiège
De Rop, Yves ULiège
Language : English
Number of pages : 59
Discipline(s) : Physical, chemical, mathematical & earth Sciences > Space science, astronomy & astrophysics
Institution(s) : Université de Liège, Liège, Belgique
Degree: Master en sciences spatiales, à finalité approfondie
Faculty: Master thesis of the Faculté des Sciences

Abstract

[en] Since a few years, the growing number of black hole merger events detected via the emission of gravitational waves motivated the investigations on the formation processes of black holes. Following this trend, this work focuses on low-mass black holes (of the order of a few solar masses or less), in particular the formation processes which differ from the direct core-collapse supernovae predicted by classical stellar evolution theory. This includes the accretion of dark matter onto neutron stars and the impact of primordial black holes on their surrounding.

As a first step, I re-derive the maximum masses of compact objects (the Chandrasekhar limit for white dwarfs and the Oppenheimer-Volkoff limit for neutron stars) and study the properties of the Kerr metric for a rotating electrically neutral black hole. Then I explore the various processes themselves.
Regarding the accretion of dark matter onto a neutron star, I compare the scenarios where the accretion concerns dark matter of bosonic or fermionic natures. I conclude that in both cases, the accumulation of dark matter would collapse into an initial black hole which can be fed by the rest of the neutron star material after that. The constraints on the mass of the dark matter particles (but also the number of particles needed, ...) will mainly depend on the existence of the degeneracy pressure due to the Pauli exclusion principle. One of the main consequences is that for a same mass of the dark matter particle, less particles will be needed in the bosonic case.
As a second step, I also analyse the primordial black holes formed in the early Universe, re-consider their impacts on their environment and examine how they could be candidates for the existence of low-mass black holes, but also how they could be candidates to explain at least partially the missing dark matter mass.
The dark matter puzzle is one of the biggest challenges in astrophysics. Since black holes created by accretion of dark matter and primordial black holes can weigh a solar mass or less, observing such objects would motivate even more the investigations as these objects are too lightweight to be produced via the collapse of the core of a massive star. Subsequently, their observations could also help us put more constraints on the nature of the dark matter.


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Author

  • Kumar, Shami ULiège Université de Liège > Master sc. spatiales, à fin.

Promotor(s)

Committee's member(s)

  • Rauw, Grégor ULiège Université de Liège - ULiège > Groupe d'astrophysique des hautes énergies (GAPHE)
    ORBi View his publications on ORBi
  • Nazé, Yaël ULiège Université de Liège - ULiège > Département d'astrophys., géophysique et océanographie (AGO) > Département d'astrophys., géophysique et océanographie (AGO)
    ORBi View his publications on ORBi
  • De Rop, Yves ULiège Université de Liège - ULiège > Département d'astrophys., géophysique et océanographie (AGO) > Inter. fondamentales en physique et astrophysique (IFPA)
    ORBi View his publications on ORBi
  • Total number of views 103
  • Total number of downloads 278










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