Astronomical observations are fundamentally different as compared to laboratory experiments. In the former case, it is not possible to change the physical conditions of the objects under examination nor to fix their physical parameters, whereas in the latter case, controlled experiments can be done. Even the whole set-up can be changed or the object under examination can be replaced with another, more suitable one and the measurements can be repeated under more or less desired conditions. On the other hand, the maximum values of physical variables that can be attained and maintained for long time intervals are highly limited in laboratory conditions. This fact is especially important in checking and finding the limitations and the boundaries of applicability of some fundamental theories in physics. Checking the limit of Einstein’s theory of gravitation for strong gravitational fields is not possible in laboratory experiments done on Earth. The only hope to have some progress in this area of exploration is related to indirect observations of black holes. Neutron stars are next to black holes in having extremely high values of some physical quantities, especially the density and the magnetic field, and they give the advantage of direct observations. The main difficulty in determining some of their intrinsic and extrinsic properties is due to the fact that determining the distances to astronomical objects is a complicated problem in many cases. The neutron star distances need to be known accurately throughout the Galaxy for example to calculate their radiative power.
{"title":"On the Galactic Distributions of Radio Pulsars and Plasma Density","authors":"A. Ankay, E. Yazgan, P. Kutukcu","doi":"10.2298/SAJ1693001A","DOIUrl":"https://doi.org/10.2298/SAJ1693001A","url":null,"abstract":"Astronomical observations are fundamentally different as compared to laboratory experiments. In the former case, it is not possible to change the physical conditions of the objects under examination nor to fix their physical parameters, whereas in the latter case, controlled experiments can be done. Even the whole set-up can be changed or the object under examination can be replaced with another, more suitable one and the measurements can be repeated under more or less desired conditions. On the other hand, the maximum values of physical variables that can be attained and maintained for long time intervals are highly limited in laboratory conditions. This fact is especially important in checking and finding the limitations and the boundaries of applicability of some fundamental theories in physics. Checking the limit of Einstein’s theory of gravitation for strong gravitational fields is not possible in laboratory experiments done on Earth. The only hope to have some progress in this area of exploration is related to indirect observations of black holes. Neutron stars are next to black holes in having extremely high values of some physical quantities, especially the density and the magnetic field, and they give the advantage of direct observations. The main difficulty in determining some of their intrinsic and extrinsic properties is due to the fact that determining the distances to astronomical objects is a complicated problem in many cases. The neutron star distances need to be known accurately throughout the Galaxy for example to calculate their radiative power.","PeriodicalId":48878,"journal":{"name":"Serbian Astronomical Journal","volume":"193 1","pages":"1-10"},"PeriodicalIF":0.5,"publicationDate":"2016-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"68673700","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Interaction between Yarkovsky Force and Mean-Motion Resonances: Some Specific Properties","authors":"I. Milic-Zitnik","doi":"10.2298/SAJ160613007Z","DOIUrl":"https://doi.org/10.2298/SAJ160613007Z","url":null,"abstract":"","PeriodicalId":48878,"journal":{"name":"Serbian Astronomical Journal","volume":"193 1","pages":"19"},"PeriodicalIF":0.5,"publicationDate":"2016-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"68673631","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
M. Drakul, V. M. vCadevz, J. Bajvceti'c, L. Popovi'c, D. Blagojevi'c, A. Nina
One of the most important parameters in ionospheric plasma research also having a wide practical application in wireless satellite telecommunications is the total electron content (TEC) representing the columnal electron number density. The F region with high electron density provides the biggest contribution to TEC while the relatively weakly ionized plasma of the D region (60 km - 90 km above Earths surface) is often considered as a negligible cause of satellite signal disturbances. However, sudden intensive ionization processes like those induced by solar X ray flares can cause relative increases of electron density that are significantly larger in the D-region than in regions at higher altitudes. Therefore, one cannot exclude a priori the D region from investigations of ionospheric influences on propagation of electromagnetic signals emitted by satellites. We discuss here this problem which has not been sufficiently treated in literature so far. The obtained results are based on data collected from the D region monitoring by very low frequency radio waves and on vertical TEC calculations from the Global Navigation Satellite System (GNSS) signal analyses, and they show noticeable variations in the D region electron content (TECD) during activity of a solar X ray flare (it rises by a factor of 136 in the considered case) when TECD contribution to TEC can reach several percent and which cannot be neglected in practical applications like global positioning procedures by satellites.
{"title":"Behaviour of electron content in the ionospheric d-region during solar x-ray flares","authors":"M. Drakul, V. M. vCadevz, J. Bajvceti'c, L. Popovi'c, D. Blagojevi'c, A. Nina","doi":"10.2298/SAJ160404006T","DOIUrl":"https://doi.org/10.2298/SAJ160404006T","url":null,"abstract":"One of the most important parameters in ionospheric plasma research also having a wide practical application in wireless satellite telecommunications is the total electron content (TEC) representing the columnal electron number density. The F region with high electron density provides the biggest contribution to TEC while the relatively weakly ionized plasma of the D region (60 km - 90 km above Earths surface) is often considered as a negligible cause of satellite signal disturbances. However, sudden intensive ionization processes like those induced by solar X ray flares can cause relative increases of electron density that are significantly larger in the D-region than in regions at higher altitudes. Therefore, one cannot exclude a priori the D region from investigations of ionospheric influences on propagation of electromagnetic signals emitted by satellites. We discuss here this problem which has not been sufficiently treated in literature so far. The obtained results are based on data collected from the D region monitoring by very low frequency radio waves and on vertical TEC calculations from the Global Navigation Satellite System (GNSS) signal analyses, and they show noticeable variations in the D region electron content (TECD) during activity of a solar X ray flare (it rises by a factor of 136 in the considered case) when TECD contribution to TEC can reach several percent and which cannot be neglected in practical applications like global positioning procedures by satellites.","PeriodicalId":48878,"journal":{"name":"Serbian Astronomical Journal","volume":"193 1","pages":"11-18"},"PeriodicalIF":0.5,"publicationDate":"2016-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"68673425","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The paper presents light curve solutions of our observations of four new ultrashort-period eclipsing binaries with MS components. Two of them have periods almost at the upper limit (0.22 days) of the ultrashort-period binaries, while the periods of around 0.18 days of CSS J171508.5+350658 and CSS J214633.8+120016 are amongst the shortest known orbital periods. CSS J171410.0+ 445850, CSS J214633.8+120016 and CSS J224326.0+154532 are over contact binaries with fill out factors around 0.25 while CSS J171508.5+350658 is a semidetached system. The two targets with shortest periods consist of M dwarfs.
{"title":"Observations and light curve solutions of four ultrashort-period binaries","authors":"D. Kjurkchieva, V. Popov, D. Vasileva, N. Petrov","doi":"10.2298/SAJ150914001K","DOIUrl":"https://doi.org/10.2298/SAJ150914001K","url":null,"abstract":"The paper presents light curve solutions of our observations of four new \u0000 ultrashort-period eclipsing binaries with MS components. Two of them have \u0000 periods almost at the upper limit (0.22 days) of the ultrashort-period \u0000 binaries, while the periods of around 0.18 days of CSS J171508.5+350658 and \u0000 CSS J214633.8+120016 are amongst the shortest known orbital periods. CSS \u0000 J171410.0+ 445850, CSS J214633.8+120016 and CSS J224326.0+154532 are \u0000 over contact binaries with fill out factors around 0.25 while CSS \u0000 J171508.5+350658 is a semidetached system. The two targets with shortest \u0000 periods consist of M dwarfs.","PeriodicalId":48878,"journal":{"name":"Serbian Astronomical Journal","volume":"192 1","pages":"21-26"},"PeriodicalIF":0.5,"publicationDate":"2016-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"68672550","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
M. Milošević, D. Dimitrijevic, G. Djordjevic, Marko Stojanovic
The role tachyon fields may play in evolution of early universe is discussed in this paper. We consider the evolution of a flat and homogeneous universe governed by a tachyon scalar field with the DBI-type action and calculate the slow-roll parameters of inflation, scalar spectral index (n), and tensor-scalar ratio (r) for the given potentials. We pay special attention to the inverse power potential, first of all to V (x) ~ x−4, and compare the available results obtained by analytical and numerical methods with those obtained by observation. It is shown that the computed values of the observational parameters and the observed ones are in a good agreement for the high values of the constant X0. The possibility that influence of the radion field can extend a range of the acceptable values of the constant X0 to the string theory motivated sector of its values is briefly considered. [Projekat Ministarstva nauke Republike Srbije, br. 176021, br. 174020 i br. 43011]
{"title":"DYNAMICS OF TACHYON FIELDS AND INFLATION - COMPARISON OF ANALYTICAL AND NUMERICAL RESULTS WITH OBSERVATION","authors":"M. Milošević, D. Dimitrijevic, G. Djordjevic, Marko Stojanovic","doi":"10.2298/SAJ160312003M","DOIUrl":"https://doi.org/10.2298/SAJ160312003M","url":null,"abstract":"The role tachyon fields may play in evolution of early universe is discussed in this paper. We consider the evolution of a flat and homogeneous universe governed by a tachyon scalar field with the DBI-type action and calculate the slow-roll parameters of inflation, scalar spectral index (n), and tensor-scalar ratio (r) for the given potentials. We pay special attention to the inverse power potential, first of all to V (x) ~ x−4, and compare the available results obtained by analytical and numerical methods with those obtained by observation. It is shown that the computed values of the observational parameters and the observed ones are in a good agreement for the high values of the constant X0. The possibility that influence of the radion field can extend a range of the acceptable values of the constant X0 to the string theory motivated sector of its values is briefly considered. [Projekat Ministarstva nauke Republike Srbije, br. 176021, br. 174020 i br. 43011]","PeriodicalId":48878,"journal":{"name":"Serbian Astronomical Journal","volume":"1 1","pages":"1-8"},"PeriodicalIF":0.5,"publicationDate":"2016-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"68673229","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
We study the well-known nearby early-type galaxy NGC 5128 (Centaurus A) and use the sample of its globular clusters to analyze its dynamics. We study both Newtonian and MOND models assuming three cases of orbital anisotropies: isotropic case, mildly tangentially anisotropic case and the radially anisotropic case based on the literature. We find that there are two regions with different values of the velocity dispersion: interior to ~ 3 effective radii the value of the velocity dispersion is approximately 150 km s−1 , whereas beyond ~ 3 effective radii its value increases to approximately 190 km s−1 , thus implying the increase of the total cumulative mass which is indicative of the existence of dark matter there in the Newtonian approach: the mass-to-light increases from M/LB = 7 in the inner regions to M/LB = 26 in the outer regions. We found that the Navarro-Frenk-White (NFW) model with dark halo provides good description of the dynamics of NGC 5128. Using three MOND models (standard, simple and toy), we find that they all provide good fits to the velocity dispersion of NGC 5128 and that no additional dark component is needed in MOND. [Projekat Ministarstva nauke Republike Srbije, br. 176021: Visible and Invisible Matter in Nearby Galaxies: Theory and Observations]
我们研究了附近著名的早期型星系NGC 5128(半人马座A)，并使用其球状星团样本来分析其动力学。我们研究了牛顿模型和MOND模型，假设轨道各向异性的三种情况:各向同性情况，轻度切向各向异性情况和径向各向异性情况。我们发现有两个区域具有不同的速度色散值:在~ 3有效半径内，速度色散值约为150 km s - 1，而在~ 3有效半径以外，其值增加到约190 km s - 1，从而意味着总累积质量的增加，这表明在牛顿方法中暗物质的存在;质量光比由内部区域的M/LB = 7增加到外部区域的M/LB = 26。我们发现带有暗晕的navarro - frank - white (NFW)模型很好地描述了NGC 5128的动力学。使用三种MOND模型(标准、简单和玩具)，我们发现它们都能很好地拟合NGC 5128的速度弥散，并且在MOND中不需要额外的暗成分。[南斯拉夫]塞族共和国部长项目;176021:邻近星系中可见与不可见物质:理论与观测]
{"title":"The Newtonian and MOND dynamical models of NGC 5128: Investigation of the dark matter contribution","authors":"S. Samurović","doi":"10.2298/SAJ160113002S","DOIUrl":"https://doi.org/10.2298/SAJ160113002S","url":null,"abstract":"We study the well-known nearby early-type galaxy NGC 5128 (Centaurus A) and use the sample of its globular clusters to analyze its dynamics. We study both Newtonian and MOND models assuming three cases of orbital anisotropies: isotropic case, mildly tangentially anisotropic case and the radially anisotropic case based on the literature. We find that there are two regions with different values of the velocity dispersion: interior to ~ 3 effective radii the value of the velocity dispersion is approximately 150 km s−1 , whereas beyond ~ 3 effective radii its value increases to approximately 190 km s−1 , thus implying the increase of the total cumulative mass which is indicative of the existence of dark matter there in the Newtonian approach: the mass-to-light increases from M/LB = 7 in the inner regions to M/LB = 26 in the outer regions. We found that the Navarro-Frenk-White (NFW) model with dark halo provides good description of the dynamics of NGC 5128. Using three MOND models (standard, simple and toy), we find that they all provide good fits to the velocity dispersion of NGC 5128 and that no additional dark component is needed in MOND. [Projekat Ministarstva nauke Republike Srbije, br. 176021: Visible and Invisible Matter in Nearby Galaxies: Theory and Observations]","PeriodicalId":48878,"journal":{"name":"Serbian Astronomical Journal","volume":"1 1","pages":"9-20"},"PeriodicalIF":0.5,"publicationDate":"2016-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"68673634","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
When a solid object is immersed into ionized gas it gets brought to a certain value of electrostatic potential and surrounded by a space charge region called ‘plasma sheath’. Through this region, particles are attracted or repelled from the surface of the charge collecting object. For collisionless plasma, this process is described by the so-called orbit limited theory, which explains how the collection of particles is determined by the collector geometry and plasma velocity distribution function (VDF). In this article, we provide explicit expressions for orbit-limited currents for generalized Lorentzian (κ) distributions. This work is useful to describe the charging processes of objects in non-collisional plasmas like the solar wind, where the electrons VDF is often observed to exhibit quasi power-law populations of suprathermal particles. It is found that these ‘suprathermals’ considerably increase the charge collection. Since the surface charging process that determines the value of electrostatic potential is also affected by the plasma VDF, calculation of the collector potential in the solar wind is described along with some quantitative predictions. [Projekat Ministarstva nauke Republike Srbije, br. 176002]
{"title":"Orbit limited theory in the solar wind - κ distributions","authors":"M. Martinović","doi":"10.2298/SAJ160220004M","DOIUrl":"https://doi.org/10.2298/SAJ160220004M","url":null,"abstract":"When a solid object is immersed into ionized gas it gets brought to a certain value of electrostatic potential and surrounded by a space charge region called ‘plasma sheath’. Through this region, particles are attracted or repelled from the surface of the charge collecting object. For collisionless plasma, this process is described by the so-called orbit limited theory, which explains how the collection of particles is determined by the collector geometry and plasma velocity distribution function (VDF). In this article, we provide explicit expressions for orbit-limited currents for generalized Lorentzian (κ) distributions. This work is useful to describe the charging processes of objects in non-collisional plasmas like the solar wind, where the electrons VDF is often observed to exhibit quasi power-law populations of suprathermal particles. It is found that these ‘suprathermals’ considerably increase the charge collection. Since the surface charging process that determines the value of electrostatic potential is also affected by the plasma VDF, calculation of the collector potential in the solar wind is described along with some quantitative predictions. [Projekat Ministarstva nauke Republike Srbije, br. 176002]","PeriodicalId":48878,"journal":{"name":"Serbian Astronomical Journal","volume":"1 1","pages":"27-34"},"PeriodicalIF":0.5,"publicationDate":"2016-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"68673213","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The solar Lyα line emission can be considered as the dominant source of ionization processes in the ionospheric D-region at altitudes above 70 km during unperturbed conditions. However, large sudden impacts of radiation in some other energy domains can also significantly influence the ionization rate and, in this paper, we present a study on the contribution of Lyα radiation to the ionization rate when the ionosphere is disturbed by solar X-flares. We give relevant analytical expressions and make calculations and numerical simulations for the low ionosphere using data collected by the VLF receiver located in Serbia for the VLF radio signal emitted by the DHO transmitter in Germany. [Projekat Ministarstva nauke Republike Srbije, br. III-44002, br. 176002 i br. 176004]
{"title":"Contribution of solar hydrogen Lyα line emission in total ionization rate in ionospheric D-region during the maximum of solar X-flare","authors":"A. Nina, V. M. vCadevz, J. Bajvceti'c","doi":"10.2298/SAJ150828003N","DOIUrl":"https://doi.org/10.2298/SAJ150828003N","url":null,"abstract":"The solar Lyα line emission can be considered as the dominant source of \u0000 ionization processes in the ionospheric D-region at altitudes above 70 km \u0000 during unperturbed conditions. However, large sudden impacts of radiation in \u0000 some other energy domains can also significantly influence the ionization \u0000 rate and, in this paper, we present a study on the contribution of Lyα \u0000 radiation to the ionization rate when the ionosphere is disturbed by solar \u0000 X-flares. We give relevant analytical expressions and make calculations and \u0000 numerical simulations for the low ionosphere using data collected by the VLF \u0000 receiver located in Serbia for the VLF radio signal emitted by the DHO \u0000 transmitter in Germany. [Projekat Ministarstva nauke Republike Srbije, br. \u0000 III-44002, br. 176002 i br. 176004]","PeriodicalId":48878,"journal":{"name":"Serbian Astronomical Journal","volume":"191 1","pages":"51-57"},"PeriodicalIF":0.5,"publicationDate":"2015-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"68672243","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
For a number of stars from the Solar neighbourhood the eccentricities of their galactocentric orbits are calculated by using a simplified procedure given by Ninkovic (2011). Eccentricities are calculated from the three-dimensional orbits around the centre of the Milky Way for the same sample of stars, by applying a model with the analytically given gravitational potential as well. The orbital eccentricities (radial span of each star) obtained in these two manners show a satisfactory agreement. It can be concluded that for typical thin-disk stars the use of such a simplified procedure, which requires much less computing time per star, in determining their motion around the Galactic centre is justified. [Projekat Ministarstva nauke Republike Srbije, br. ON176011: Kinematics and dynamics of celestial bodies and systems]
{"title":"A Simplified Approach to Kinematics of Stars in Solar Neighbourhood","authors":"M. Stojanović","doi":"10.2298/SAJ150915005S","DOIUrl":"https://doi.org/10.2298/SAJ150915005S","url":null,"abstract":"For a number of stars from the Solar neighbourhood the eccentricities of \u0000 their galactocentric orbits are calculated by using a simplified procedure \u0000 given by Ninkovic (2011). Eccentricities are calculated from the \u0000 three-dimensional orbits around the centre of the Milky Way for the same \u0000 sample of stars, by applying a model with the analytically given \u0000 gravitational potential as well. The orbital eccentricities (radial span of \u0000 each star) obtained in these two manners show a satisfactory agreement. It \u0000 can be concluded that for typical thin-disk stars the use of such a \u0000 simplified procedure, which requires much less computing time per star, in \u0000 determining their motion around the Galactic centre is justified. [Projekat \u0000 Ministarstva nauke Republike Srbije, br. ON176011: Kinematics and dynamics of \u0000 celestial bodies and systems]","PeriodicalId":48878,"journal":{"name":"Serbian Astronomical Journal","volume":"9 1","pages":"75-80"},"PeriodicalIF":0.5,"publicationDate":"2015-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"68672632","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
We follow trajectories of kicked black holes in static and evolving dark matter halo potential. We explore both NFW and Einasto dark matter density distributions. The considered dark matter halos represent hosts of massive spiral and elliptical field galaxies. We study the critical amplitude of kick velocity necessary for complete black hole ejection at various redshifts and find that ∼ 40% lower kick velocities can remove black holes from their host haloes at z = 7 compared to z = 1. The greatest difference between the static and evolving potential occurs near the critical velocity for black hole ejection and at high redshifts. When NFW and Einasto density distributions are compared ∼ 30% higher kick velocities are needed for complete removal of BHs from dark matter halo described by the NFW profile.
{"title":"Recoiling Black Holes in Static and Evolving Dark Matter Halo Potential","authors":"M. Smole","doi":"10.2298/SAJ150706001S","DOIUrl":"https://doi.org/10.2298/SAJ150706001S","url":null,"abstract":"We follow trajectories of kicked black holes in static and evolving dark matter halo potential. We explore both NFW and Einasto dark matter density distributions. The considered dark matter halos represent hosts of massive spiral and elliptical field galaxies. We study the critical amplitude of kick velocity necessary for complete black hole ejection at various redshifts and find that ∼ 40% lower kick velocities can remove black holes from their host haloes at z = 7 compared to z = 1. The greatest difference between the static and evolving potential occurs near the critical velocity for black hole ejection and at high redshifts. When NFW and Einasto density distributions are compared ∼ 30% higher kick velocities are needed for complete removal of BHs from dark matter halo described by the NFW profile.","PeriodicalId":48878,"journal":{"name":"Serbian Astronomical Journal","volume":"43 1","pages":"17-28"},"PeriodicalIF":0.5,"publicationDate":"2015-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"68672666","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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