Персона: Кириллов, Александр Александрович
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Институт ядерной физики и технологий
Цель ИЯФиТ и стратегия развития - создание и развитие научно-образовательного центра мирового уровня в области ядерной физики и технологий, радиационного материаловедения, физики элементарных частиц, астрофизики и космофизики.
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Кириллов
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Александр Александрович
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- ПубликацияОткрытый доступCosmological Formation of (2+1)-Dimensional Soliton Structures in Models Possessing Potentials with Local Peaks(2021) Murygin, B. S.; Kirillov, A. A.; Nikulin, V. V.; Мурыгин, Борис Сергеевич; Кириллов, Александр Александрович; Никулин, Валерий ВладимировичProduction of domain walls and string-like solitons in the model with two real scalar fields and potential with at least one saddle point and a local maximum is considered. The model is regarded as 2-dimensional spatial slices of 3-dimensional entire structures. It is shown that, in the early Universe, both types of solitons may appear. In addition, the qualitative estimate of the domain walls and strings formation probabilities is presented. It is found that the probability of the formation of string-like solitons is suppressed compared to that of domain walls.
- ПубликацияОткрытый доступThe Merger Rate of Black Holes in a Primordial Black Hole Cluster(2021) Stasenko, V. D.; Kirillov, A. A.; Стасенко, Виктор Дмитриевич; Кириллов, Александр АлександровичIn this paper, the merger rate of black holes in a cluster of primordial black holes (PBHs) is investigated. The clusters have characteristics close to those of typical globular star clusters. A cluster that has a wide mass spectrum ranging from 10(-2) to 10M(circle dot) (Solar mass) and contains a massive central black hole of the mass M-center dot=10(3) M-circle dot is considered. It is shown that in the process of the evolution of cluster, the merger rate changed significantly, and by now, the PBH clusters have passed the stage of active merging of the black holes inside them.
- ПубликацияОткрытый доступThe mechanism of domain walls and strings formation in the early Universe(2020) Kirillov, A. A.; Murygin, B. S.; Кириллов, Александр Александрович; Мурыгин, Борис Сергеевич© Published under licence by IOP Publishing Ltd.A classical dynamics of two real scalar fields within a model with a saddle point potential in (2+1)-space-Time is discussed. We show that in this model, solitons may be formed both as domain walls and strings in three dimensional physical space. The formation and evolution of these field configurations are considered.
- ПубликацияОткрытый доступEvolution of the cluster of primordial black holes within the Fokker-Planck approach(2020) Stasenko, V. D.; Kirillov, A. A.; Стасенко, Виктор Дмитриевич; Кириллов, Александр Александрович© Published under licence by IOP Publishing Ltd.The calculation results of the evolution of the cluster of primordial black holes based on the Fokker-Planck equation with neglecting of the gas accretion onto black holes are presented. In addition, we consider how a massive black hole located within the cluster center affects on its evolution. Despite it creates an additional potential in the central region of the cluster and might capture surrounding black holes, a negligible growth rate of a central black hole was shown for 1 Gyr. Furthermore, we find a significant (approximately tenfold) expansion of the cluster.
- ПубликацияОткрытый доступClusters of Primordial Black Holes(2019) Eroshenko, Y. N.; Khlopov, M. Y.; Belotsky, K. M.; Dokuchaev, V. I.; Esipova, E. A.; Khromykh, L. A.; Kirillov, A. A.; Nikulin, V. V.; Rubin, S. G.; Svadkovsky, I. V.; Белоцкий, Константин Михайлович; Есипова, Екатерина Александровна; Кириллов, Александр Александрович; Никулин, Валерий Владимирович; Рубин, Сергей Георгиевич; Свадковский, Игорь Витальевич© 2019, The Author(s). The Primordial Black Holes (PBHs) are a well-established probe for new physics in the very early Universe. We discuss here the possibility of PBH agglomeration into clusters that may have several prominent observable features. The clusters can form due to closed domain walls appearance in the natural and hybrid inflation models whose subsequent evolution leads to PBH formation. The dynamical evolution of such clusters discussed here is of crucial importance. Such a model inherits all the advantages of uniformly distributed PBHs, like possible explanation of supermassive black holes existence (origin of the early quasars), the binary black hole mergers registered by LIGO/Virgo through gravitational waves, which could provide ways to test the model in future, the contribution to reionization of the Universe. If PBHs form clusters, they could alleviate or completely avoid existing constraints on the abundance of uniformly distributed to PBH, thus allowing PBH to be a viable dark matter candidate. Most of the existing constraints on uniform PBH density should be re-considered to the case of PBH clustering. Furthermore, unidentified cosmic gamma-ray point-like sources could be (partially) accounted. We conclude that models leading to PBH clustering are favored compared to models predicting the uniform distribution of PBHs.
- ПубликацияТолько метаданныеFormation of Primordial Black Hole Clusters from Phase Transitions in the Early Universe(2019) Nikulin, V. V.; Rubin, S. G.; Kirillov, A. A.; Khromykh, L. A.; Никулин, Валерий Владимирович; Рубин, Сергей Георгиевич; Кириллов, Александр Александрович© 2019, Allerton Press, Inc. A new model of the formation of primordial black holes (PBHs) is considered. The PBH generation mechanism is based on the collapse of massive walls formed in a scalar field during second-order phase transitions caused by quantum fluctuations during inflation. An essential feature of the mechanism is the formation of primordial black holes in the form of clusters. An analytical spectrum of PBH masses is obtained. We also demonstrate the possibility of forming the clusters with a total mass of ∼ 10 5 –10 8 M ☉ , ∼ 1 pc in size, and ∼ 10 11 in number, which corresponds to the observational data on the number of galaxies in the visible region of the Universe. The prospect for the use of the proposed approach as a new scenario of the formation of galactic nuclei in the early Universe is shown.
- ПубликацияОткрытый доступThe gravitational dynamics of the primordial black holes cluster(2019) Khromykh, L. A.; Kirillov, A. A.; Кириллов, Александр Александрович© Published under licence by IOP Publishing Ltd.We consider the numerical simulation of the N-body problem related to the primordial black holes (PBHs) cluster. To study the dynamics of the system we use modified NBODY6++ code aimed at the simulation of globular star clusters. Some qualitative results describing the evolution of the system are discussed. It is shown that the cluster successfully survives to the redshift z ∼ 20 ÷ 40 (despite evaporation and coalescence of the PBHs). Starting from this moment an accretion begins to play significant role in speeding up the mass growth of the massive bodies.
- ПубликацияТолько метаданныеOn Mass Spectra of Primordial Black Holes(2021) Kirillov, A. A.; Rubin, S. G.; Кириллов, Александр Александрович; Рубин, Сергей ГеоргиевичCopyright © 2021 Kirillov and Rubin.Evidence for the primordial black holes (PBH) presence in the early Universe renews permanently. New limits on their mass spectrum challenge existing models of PBH formation. One of the known models is based on the closed walls collapse after the inflationary epoch. Its intrinsic feature is the multiple production of small mass PBH which might contradict observations in the nearest future. We show that the mechanism of walls collapse can be applied to produce substantially different PBH mass spectra if one takes into account the classical motion of scalar fields together with their quantum fluctuations at the inflationary stage. Analytical formulas have been developed that contain both quantum and classical contributions.
- ПубликацияОткрытый доступАстрофизические проявления экзотических мелкомасштабных объектов гало галактики(НИЯУ МИФИ, 2013) Кириллов, А. А.; Кириллов, Александр Александрович; Хлопов, М. Ю.
- ПубликацияТолько метаданныеDynamics and Merger Rate of Primordial Black Holes in a Cluster(2022) Stasenko, V. D.; Kirillov, A. A.; Belotskiy, K. M.; Стасенко, Виктор Дмитриевич; Кириллов, Александр Александрович; Белоцкий, Константин Михайлович© 2022 by the authors. Licensee MDPI, Basel, Switzerland.The PBH clusters can be sources of gravitational waves, and the merger rate depends on the spatial distribution of PBHs in the cluster which changes over time. It is well known that gravitational collisional systems experience the core collapse that leads to significant increase of the central density and shrinking of the core. After core collapse, the cluster expands almost self-similarly (i.e., density profile extends in size without changing its shape). These dynamic processes affect the merger rate of PBHs. In this paper, the dynamics of the PBH cluster is considered using the Fokker–Planck equation. We calculate the merger rate of PBHs on cosmic time scales and show that its time dependence has a unique signature. Namely, it grows by about an order of magnitude at the moment of core collapse which depends on the characteristics of the cluster, and then decreases according to the dependence R ∝ t−1.48 . It was obtained for monochromatic and power-law PBH mass distributions with some fixed parameters. Obtained results can be used to test the model of the PBH clusters via observation of gravitational waves at high redshift.