Search

Your search keyword '"Sunyaev, R.A."' showing total 152 results
Start Over Author "Sunyaev, R.A."
152 results on '"Sunyaev, R.A."'

3. Spectral distortions of the CMB as a probe of inflation, recombination, structure formation and particle physics: Astro2020 Science White Paper

Author

Chluba, J., Kogut, A., Patil, S.P., Abitbol, M.H., Aghanim, N., Ali-Haïmoud, Y., Amin, M.A., Aumont, J., Bartolo, N., Basu, K., Battistelli, E.S., Battye, R., Baumann, D., Ben-Dayan, I., Bolliet, B., Bond, J.R., Bouchet, F.R., Burgess, C.P., Burigana, C., Byrnes, C.T., Cabass, G., Chuss, D.T., Clesse, S., Cole, P.S., Dai, L., de Bernardis, P., Delabrouille, J., Desjacques, V., de Zotti, G., Diacoumis, J.A.D., Dimastrogiovanni, E., Di Valentino, E., Dunkley, J., Durrer, R., Dvorkin, C., Ellis, J., Eriksen, H.K., Fasiello, M., Fixsen, D., Finelli, F., Flauger, R., Galli, S., Garcia-Bellido, J., Gervasi, M., Gluscevic, V., Grin, D., Hart, L., Hernandez-Monteagudo, C., Hill, J.C., Jeong, D., Johnson, B.R., Lagache, G., Lee, E., Lewis, A., Liguori, M., Kamionkowski, M., Khatri, R., Kohri, K., Komatsu, E., Kunze, K.E., Mangilli, A., Masi, S., Mather, J., Matarrese, S., Miville-Deschênes, M.A., Montaruli, T., Münchmeyer, M., Mukherjee, S., Nakama, T., Nati, F., Ota, A., Page, L.A., Pajer, E., Poulin, Vivian, Ravenni, A., Reichardt, C., Remazeilles, M., Rotti, A., Rubiño-Martin, J.A., Sarkar, A., Sarkar, S., Savini, G., Scott, D., Serpico, P.D., Silk, J., Souradeep, T., Spergel, D.N., Starobinsky, A.A., Subrahmanyan, R., Sunyaev, R.A., Switzer, E., Tartari, A., Tashiro, H., Basu Thakur, R., Trombetti, T., Wallisch, B., Wandelt, B.D., Wehus, I.K., Wollack, E.J., Zaldarriaga, M., Zannoni, M., Jodrell Bank Centre for Astrophysics (JBCA), University of Manchester [Manchester], NASA, Institut d'astrophysique spatiale (IAS), Université Paris-Sud - Paris 11 (UP11)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Centre National d’Études Spatiales [Paris] (CNES), Institut de recherche en astrophysique et planétologie (IRAP), Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Centre National de la Recherche Scientifique (CNRS), Institut d'Astrophysique de Paris (IAP), Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), AstroParticule et Cosmologie (APC (UMR_7164)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité), Département d'Astrophysique (ex SAP) (DAP), Institut de Recherches sur les lois Fondamentales de l'Univers (IRFU), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay, Laboratoire d'Astrophysique de Marseille (LAM), Aix Marseille Université (AMU)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS), Astrophysique Interprétation Modélisation (AIM (UMR7158 / UMR_E_9005 / UM_112)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), Institut Lagrange de Paris, Laboratoire Univers et Particules de Montpellier (LUPM), Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS), Laboratoire d'Annecy-le-Vieux de Physique Théorique (LAPTH), Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS), European Project: 725456,CMBSPEC, Université Paris-Sud - Paris 11 (UP11)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Institut national des sciences de l'Univers (INSU - CNRS)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Observatoire Midi-Pyrénées (OMP), Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS)-Université de Paris (UP), Astrophysique Interprétation Modélisation (AIM (UMR_7158 / UMR_E_9005 / UM_112)), Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris Diderot - Paris 7 (UPD7), Sorbonne Université (SU), Université Montpellier 2 - Sciences et Techniques (UM2)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS), Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS), Observatoire de Paris, PSL Research University (PSL)-PSL Research University (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Sorbonne Universités, Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Observatoire de Paris, PSL Research University (PSL)-PSL Research University (PSL)-Université Paris Diderot - Paris 7 (UPD7), Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Aix Marseille Université (AMU)-Centre National d'Études Spatiales [Toulouse] (CNES), and Université de Montpellier (UM)-Université Montpellier 2 - Sciences et Techniques (UM2)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS)

Subjects
polarization: anisotropy, new physics, redshift: dependence, formation, Astrophysics::Cosmology and Extragalactic Astrophysics, dark matter: density, recombination, inflation: model, cosmic background radiation: temperature, cosmic background radiation: energy spectrum, ionization, spectral, correlation function, structure, history, numerical calculations, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph]
Abstract

International audience; Following the pioneering observations with COBE in the early 1990s, studies of the cosmic microwave background (CMB) have focused on temperature and polarization anisotropies. CMB spectral distortions - tiny departures of the CMB energy spectrum from that of a perfect blackbody - provide a second, independent probe of fundamental physics, with a reach deep into the primordial Universe. The theoretical foundation of spectral distortions has seen major advances in recent years, which highlight the immense potential of this emerging field. Spectral distortions probe a fundamental property of the Universe - its thermal history - thereby providing additional insight into processes within the cosmological standard model (CSM) as well as new physics beyond. Spectral distortions are an important tool for understanding inflation and the nature of dark matter. They shed new light on the physics of recombination and reionization, both prominent stages in the evolution of our Universe, and furnish critical information on baryonic feedback processes, in addition to probing primordial correlation functions at scales inaccessible to other tracers. In principle the range of signals is vast: many orders of magnitude of discovery space could be explored by detailed observations of the CMB energy spectrum. Several CSM signals are predicted and provide clear experimental targets, some of which are already observable with present-day technology. Confirmation of these signals would extend the reach of the CSM by orders of magnitude in physical scale as the Universe evolves from the initial stages to its present form. The absence of these signals would pose a huge theoretical challenge, immediately pointing to new physics.

Published
2019

4. Two sources of diffuse X-ray emission from the Galactic Centre

Author

Markevitch, M., Sunyaev, R.A., and Pavlinsky, M.

Subjects
X-ray astronomy -- Research, Galactic center -- Analysis, Environmental issues, Science and technology, Zoology and wildlife conservation
Abstract

The scattering of incident X-rays in the dense massive clouds of molecular gas originating from the region of Galactic Center may have been caused by the diffuse emission above 10 KeV. The changing spatial distribution and the presence of a pronounced absorption feature in the emission spectrum in the energy range 8-11 KeV shows that the scattering of X-rays from the neighboring compact sources by the dense molecular clouds causes the high energy emissions.

Published
1993

5. Fitting along the Fundamental Plane: New comparisons of jet physics across the black hole mass scale

Author

Markoff, S., Nowak, M.A., Maitra, D., Wilms, J., Gallo, E., Hynes, R., Plotkin, R.M., Romero, G.E., Sunyaev, R.A., Belloni, T., and High Energy Astrophys. & Astropart. Phys (API, FNWI)

Subjects
Physics, Supermassive black hole, Astrophysics::High Energy Astrophysical Phenomena, Astronomy, Astronomy and Astrophysics, Astrophysics, Black hole, General Relativity and Quantum Cosmology, Binary black hole, Rotating black hole, Space and Planetary Science, Intermediate-mass black hole, Stellar black hole, Spin-flip, Schwarzschild radius
Abstract

Correlations between the radio and X-ray bands in the hard state of black hole X-ray binaries (BHBs) have led to the discovery of the Fundamental Plane of black hole accretion, linking accretion-driven radiative attributes to black hole mass. Although this discovery has led to new constraints on radiative efficiencies, there is still significant degeneracy in terms of understanding the governing physics. I present several new results exploring the processes driving the Fundamental Plane over the black hole mass range. These include the first ever homogeneous fits of sources at approximately the same Eddington luminosity but millions of times different in mass, which I focus on for this proceeding article.

Published
2011

6. The Jet in the Galactic Center: An Ideal Laboratory for Magnetohydrodynamics and General Relativity

Author

Falcke, H., Markoff, S., Bower, G.C., Gammie, C.F., Mościbrodzka, M., Maitra, D., Romero, G.E., Sunyaev, R.A., Belloni, T., and High Energy Astrophys. & Astropart. Phys (API, FNWI)

Subjects
High Energy Astrophysical Phenomena (astro-ph.HE), Physics, Cosmology and Nongalactic Astrophysics (astro-ph.CO), General relativity, Event horizon, Strong gravity, Astrophysics::High Energy Astrophysical Phenomena, Galactic Center, FOS: Physical sciences, Astronomy and Astrophysics, General Relativity and Quantum Cosmology (gr-qc), Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, General Relativity and Quantum Cosmology, Black hole, Gravitation, Space and Planetary Science, Very-long-baseline interferometry, Astrophysics - High Energy Astrophysical Phenomena, Schwarzschild radius, Astrophysics::Galaxy Astrophysics, Astrophysics - Cosmology and Nongalactic Astrophysics
Abstract

In this paper we review and discuss some of the intriguing properties of the Galactic Center supermassive black hole candidate Sgr A*. Of all possible black hole sources, the event horizon of Sgr A*, subtends the largest angular scale on the sky. It is therefore a prime candidate to study and image plasma processes in strong gravity and it even allows imaging of the shadow cast by the event horizon. Recent mm-wave VLBI and radio timing observations as well as numerical GRMHD simulations now have provided several breakthroughs that put Sgr A* back into the focus. Firstly, VLBI observations have now measured the intrinsic size of Sgr A* at multiple frequencies, where the highest frequency measurements have approached the scale of the black hole shadow. Moreover, measurements of the radio variability show a clear time lag between 22 GHz and 43 GHz. The combination of size and timing measurements, allows one to actually measure the flow speed and direction of magnetized plasma at some tens of Schwarzschild radii. This data strongly support a moderately relativistic outflow, consistent with an accelerating jet model. This is compared to recent GRMHD simulation that show the presence of a moderately relativistic outflow coupled to an accretion flow Sgr A*. Further VLBI and timing observations coupled to simulations have the potential to map out the velocity profile from 5-40 Schwarzschild radii and to provide a first glimpse at the appearance of a jet-disk system near the event horizon. Future submm-VLBI experiments would even be able to directly image those processes in strong gravity and directly confirm the presence of an event horizon., invited talk to appear in "Jets on All Scales", IAU Symposium 275, G.E. Romero, R.A. Sunyaev & T. Belloni, eds., Cambridge University Press, 9 pages, LaTex, 4 figures

Published
2010

7. Geometric techniques for implicit two-dimensional systems

Author

Romero G.E., Sunyaev R.A., Belloni T.M., Ntogramatzidis, Lorenzo, Cantoni, Michael, Romero G.E., Sunyaev R.A., Belloni T.M., Ntogramatzidis, Lorenzo, and Cantoni, Michael

Abstract

Geometric tools are developed for two-dimensional (2-D) models in an implicitFornasini–Marchesini form. In particular, the structural properties of controlled and conditionedinvariance are defined and studied. These properties are investigated in terms ofquarter-plane causal solutions of the implicit model given compatible boundary conditions.The definitions of controlled and conditioned invariance introduced, along with the correspondingoutput-nulling and input-containing subspaces, are shown to be richer than theone-dimensional counterparts. The analysis carried out in this paper establishes necessaryand sufficient conditions for the solvability of 2-D disturbance decoupling problems andunknown-input observation problems. The conditions obtained are expressed in terms ofoutput-nulling and input-containing subspaces, which can be computed recursively in a finitenumber of steps.

Published
2013

9. The Hipparcos mission.

Author

Burton, W.B., Bertola, F., Cassinelli, J.P., Cesarsky, C.J., Ehrenfreund, P., Engvold, O., Heck, A., Den Heuvel, E.P.J. van, Kaspi, V.M., Kuijpers, J.M.E., Der Laan, H. van, Murdin, P.G., Pacini, F., Radhakrishnan, V., Somov, B.V., Sunyaev, R.A., and Leeuwen, Floor van

Published
2007
Full Text
View/download PDF

10. Gaia.

Author

Burton, W.B., Bertola, F., Cassinelli, J.P., Cesarsky, C.J., Ehrenfreund, P., Engvold, O., Heck, A., Den Heuvel, E.P.J. van, Kaspi, V.M., Kuijpers, J.M.E., Der Laan, H. van, Murdin, P.G., Pacini, F., Radhakrishnan, V., Somov, B.V., Sunyaev, R.A., and Leeuwen, Floor van

Published
2007
Full Text
View/download PDF

11. The torques on Hipparcos as observed over the mission.

Author

Burton, W.B., Bertola, F., Cassinelli, J.P., Cesarsky, C.J., Ehrenfreund, P., Engvold, O., Heck, A., Den Heuvel, E.P.J. van, Kaspi, V.M., Kuijpers, J.M.E., Der Laan, H. van, Murdin, P.G., Pacini, F., Radhakrishnan, V., Somov, B.V., Sunyaev, R.A., and Leeuwen, Floor van

Published
2007
Full Text
View/download PDF

12. The Photometric Data.

Author

Burton, W.B., Bertola, F., Cassinelli, J.P., Cesarsky, C.J., Ehrenfreund, P., Engvold, O., Heck, A., Den Heuvel, E.P.J. van, Kaspi, V.M., Kuijpers, J.M.E., Der Laan, H. van, Murdin, P.G., Pacini, F., Radhakrishnan, V., Somov, B.V., Sunyaev, R.A., and Leeuwen, Floor van

Published
2007
Full Text
View/download PDF

13. Payload calibrations.

Author

Burton, W.B., Bertola, F., Cassinelli, J.P., Cesarsky, C.J., Ehrenfreund, P., Engvold, O., Heck, A., Den Heuvel, E.P.J. van, Kaspi, V.M., Kuijpers, J.M.E., Der Laan, H. van, Murdin, P.G., Pacini, F., Radhakrishnan, V., Somov, B.V., Sunyaev, R.A., and Leeuwen, Floor van

Published
2007
Full Text
View/download PDF

14. Spacecraft-Parameter Calibrations.

Author

Burton, W.B., Bertola, F., Cassinelli, J.P., Cesarsky, C.J., Ehrenfreund, P., Engvold, O., Heck, A., Den Heuvel, E.P.J. van, Kaspi, V.M., Kuijpers, J.M.E., Der Laan, H. van, Murdin, P.G., Pacini, F., Radhakrishnan, V., Somov, B.V., Sunyaev, R.A., and Leeuwen, Floor van

Published
2007
Full Text
View/download PDF

15. The mission timeline.

Author

Burton, W.B., Bertola, F., Cassinelli, J.P., Cesarsky, C.J., Ehrenfreund, P., Engvold, O., Heck, A., Den Heuvel, E.P.J. van, Kaspi, V.M., Kuijpers, J.M.E., Der Laan, H. van, Murdin, P.G., Pacini, F., Radhakrishnan, V., Somov, B.V., Sunyaev, R.A., and Leeuwen, Floor van

Published
2007
Full Text
View/download PDF

16. Fully-dynamic attitude fitting.

Author

Burton, W.B., Bertola, F., Cassinelli, J.P., Cesarsky, C.J., Ehrenfreund, P., Engvold, O., Heck, A., Den Heuvel, E.P.J. van, Kaspi, V.M., Kuijpers, J.M.E., Der Laan, H. van, Murdin, P.G., Pacini, F., Radhakrishnan, V., Somov, B.V., Sunyaev, R.A., and Leeuwen, Floor van

Published
2007
Full Text
View/download PDF

17. Kinematics of the solar neighbourhood.

Author

Burton, W.B., Bertola, F., Cassinelli, J.P., Cesarsky, C.J., Ehrenfreund, P., Engvold, O., Heck, A., Den Heuvel, E.P.J. van, Kaspi, V.M., Kuijpers, J.M.E., Der Laan, H. van, Murdin, P.G., Pacini, F., Radhakrishnan, V., Somov, B.V., Sunyaev, R.A., and Leeuwen, Floor van

Published
2007
Full Text
View/download PDF

18. A free-floating rigid body in space.

Author

Burton, W.B., Bertola, F., Cassinelli, J.P., Cesarsky, C.J., Ehrenfreund, P., Engvold, O., Heck, A., Den Heuvel, E.P.J. van, Kaspi, V.M., Kuijpers, J.M.E., Der Laan, H. van, Murdin, P.G., Pacini, F., Radhakrishnan, V., Somov, B.V., Sunyaev, R.A., and Leeuwen, Floor van

Published
2007
Full Text
View/download PDF

19. Individual, single stars.

Author

Burton, W.B., Bertola, F., Cassinelli, J.P., Cesarsky, C.J., Ehrenfreund, P., Engvold, O., Heck, A., Den Heuvel, E.P.J. van, Kaspi, V.M., Kuijpers, J.M.E., Der Laan, H. van, Murdin, P.G., Pacini, F., Radhakrishnan, V., Somov, B.V., Sunyaev, R.A., Leeuwen, Floor van, and van Leeuwen, Floor

Published
2007
Full Text
View/download PDF

20. Hipparcos astrometry.

Author

Burton, W.B., Bertola, F., Cassinelli, J.P., Cesarsky, C.J., Ehrenfreund, P., Engvold, O., Heck, A., Den Heuvel, E.P.J. van, Kaspi, V.M., Kuijpers, J.M.E., Der Laan, H. van, Murdin, P.G., Pacini, F., Radhakrishnan, V., Somov, B.V., Sunyaev, R.A., and Leeuwen, Floor van

Published
2007
Full Text
View/download PDF

21. Groups of single stars.

Author

Burton, W.B., Bertola, F., Cassinelli, J.P., Cesarsky, C.J., Ehrenfreund, P., Engvold, O., Heck, A., Den Heuvel, E.P.J. van, Kaspi, V.M., Kuijpers, J.M.E., Der Laan, H. van, Murdin, P.G., Pacini, F., Radhakrishnan, V., Somov, B.V., Sunyaev, R.A., and Leeuwen, Floor van

Published
2007
Full Text
View/download PDF

23. Hyperfine Structure Radio Lines from Hot Gas in Elliptical Galaxies and Groups of Galaxies.

Author

Leibundgut, Bruno, Böhringer, H., Pratt, G.W., Finoguenov, A., Schuecker, P., Docenko, D., and Sunyaev, R.A.

Abstract

Observations of intracluster gas bulk motions and turbulence in clusters and groups of galaxies should provide important information about physical conditions in the intergalactic gas. Thanks to the high spectral resolution of radio detectors, hyperfine structure (HFS) lines of highly-charged ions might help in this respect. Though not yet observed, intensities of emission and absorption HFS lines from the hot interstellar medium of elliptical galaxies and the intracluster medium of groups of galaxies are estimated to be on the limit of the abilities of existing instruments. The most interesting lines for this purpose are discussed. [ABSTRACT FROM AUTHOR]

Published
2007
Full Text
View/download PDF

24. Overview.

Author

Bertola, F., Cassinelli, J.P., Cesarsky, C.J., Ehrenfreund, P., Engvold, O., Heck, A., van den Heuvel, E.P.J., Kaspi, V.M., Kuijpers, J.M.E., van der Laan, H., Murdin, P.G., Pacini, F., Radhakrishnan, V., Somov, B.V., Sunyaev, R.A., Haensel, P., Potekhin, A. Y., and Yakovlev, D. G.

Abstract

Neutron stars are compact stars which contain matter of supranuclear density in their interiors (presumably with a large fraction of neutrons). They have typical masses M ∼ 1.4M⊙ and radii R ∼ 10 km. Thus, their masses are close to the solar mass M⊙ = 1.989 × 1033 g, but their radii are ∼ 105 times smaller than the solar radius R⊙ = 6.96×105 km. Accordingly, neutron stars possess an enormous gravitational energy Egrav and surface gravity g, (1.1)$$ \begin{gathered} E_{grav} \sim GM^2 /R \sim 5 \times 10^{53} erg \sim 0.2Mc^2 , \hfill \\ g \sim GM/R^2 \sim 2 \times 10^{14} cm{\text{ }}s^{ - 2} , \hfill \\ \end{gathered} $$ where G is the gravitational constant and c is the speed of light. Clearly, neutron stars are very dense. Their mean mass density is (1.2)$$ \bar \rho \simeq 3M/(4\pi R^3 ) \simeq 7 \times 10^{14} g cm^{{\text{ - 3}}} \sim (2 - 3)\rho _0 , $$ where ρ0 = 2.8 × 1014 g cm−3 is the so called normal nuclear density, the mass density of nucleon matter in heavy atomic nuclei. The central density of neutron stars is even larger, reaching (10-20) ρ0. By all means, neutron stars are the most compact stars known in the Universe. [ABSTRACT FROM AUTHOR]

Published
2007
Full Text
View/download PDF

25. Strange Matter and Strange Stars.

Author

Bertola, F., Cassinelli, J.P., Cesarsky, C.J., Ehrenfreund, P., Engvold, O., Heck, A., van den Heuvel, E.P.J., Kaspi, V.M., Kuijpers, J.M.E., van der Laan, H., Murdin, P.G., Pacini, F., Radhakrishnan, V., Somov, B.V., Sunyaev, R.A., Haensel, P., Potekhin, A. Y., and Yakovlev, D. G.

Abstract

This chapter is different from others. It deals with objects which, at the time of this writing, are hypothetical. We do not know whether strange matter and strange stars exist or not. We start with the discussion of the strange matter hypothesis (§8.3). Its history is described in §8.4. Models of strange matter are presented in §§8.5-8.8. Finally, §8.9 is devoted to other speculative self-bound phases of super-dense matter. [ABSTRACT FROM AUTHOR]

Published
2007
Full Text
View/download PDF

26. Theory Versus Observations.

Author

Bertola, F., Cassinelli, J.P., Cesarsky, C.J., Ehrenfreund, P., Engvold, O., Heck, A., van den Heuvel, E.P.J., Kaspi, V.M., Kuijpers, J.M.E., van der Laan, H., Murdin, P.G., Pacini, F., Radhakrishnan, V., Somov, B.V., Sunyaev, R.A., Haensel, P., Potekhin, A. Y., and Yakovlev, D. G.

Abstract

As discussed in Chapter 5, the fundamental problem of the EOS of neutronstar cores cannot be solved on purely theoretical basis: there is no strict theory but many theoretical models instead. Therefore, one can try to select (constrain) the true model using observations. In the present Chapter we will describe some results of this activity. The methods to constrain the EOS are numerous. The activity started just from the discovery of neutron stars in 1967 (Chapter 1). The results obtained by the time of this writing (2006) are a tremendous challenge of observational astrophysics, but look like a failure in their essence: the EOS has been only weakly constrained by observations. [ABSTRACT FROM AUTHOR]

Published
2007
Full Text
View/download PDF

27. Neutron Stars with Exotic Cores.

Author

Bertola, F., Cassinelli, J.P., Cesarsky, C.J., Ehrenfreund, P., Engvold, O., Heck, A., van den Heuvel, E.P.J., Kaspi, V.M., Kuijpers, J.M.E., van der Laan, H., Murdin, P.G., Pacini, F., Radhakrishnan, V., Somov, B.V., Sunyaev, R.A., Haensel, P., Potekhin, A. Y., and Yakovlev, D. G.

Abstract

It has been recognized since the 1960s that with increasing density ρ above the standard nuclear-matter density ρ0 the matter can undergo phase transitions to states qualitatively different from the state at ρ ∼ ρ0. These high-density phases are exotic by the standards of terrestrial nuclear physics. Their possible existence above some threshold densities results from assumed specific features of strong (hadronic) interactions (pion condensation, kaon condensation) and the quark structure of baryons (quark deconfinement). [ABSTRACT FROM AUTHOR]

Published
2007
Full Text
View/download PDF

28. Neutron Star Cores: Nucleons and Hyperons.

Author

Bertola, F., Cassinelli, J.P., Cesarsky, C.J., Ehrenfreund, P., Engvold, O., Heck, A., van den Heuvel, E.P.J., Kaspi, V.M., Kuijpers, J.M.E., van der Laan, H., Murdin, P.G., Pacini, F., Radhakrishnan, V., Somov, B.V., Sunyaev, R.A., Haensel, P., Potekhin, A. Y., and Yakovlev, D. G.

Abstract

As we have seen in §3.5, nuclei cannot exist at densities exceeding ∼ (1.5 − 2.0) × 1014 g cm−3. At these densities the matter becomes a uniform plasma of neutrons, protons, and electrons. Up to ρ ∼ 2ρ0 its properties can be calculated in a rather reliable way using the methods of the nuclear many-body theory, which have been applied with some success for the microscopic description of ordinary nuclear structure. At such densities the only baryons present in the ground state of the matter are nucleons which are in beta equilibrium with electrons (and muons if the electron Fermi energy exceeds mμc2 = 105.7 MeV). The shell of the neutron-star core with densities ρ ≲ 2ρ0 is called the outer core. Its matter will be called the npeμ matter. At higher densities our assumption of the npeμ composition of dense matter can be invalid because the matter may contain hyperons. The derivation of the equation of state (EOS) of the matter composed of nucleons, hyperons, electrons, and muons will be the topic of the present chapter. [ABSTRACT FROM AUTHOR]

Published
2007
Full Text
View/download PDF

29. Neutron Star Structure.

Author

Bertola, F., Cassinelli, J.P., Cesarsky, C.J., Ehrenfreund, P., Engvold, O., Heck, A., van den Heuvel, E.P.J., Kaspi, V.M., Kuijpers, J.M.E., van der Laan, H., Murdin, P.G., Pacini, F., Radhakrishnan, V., Somov, B.V., Sunyaev, R.A., Haensel, P., Potekhin, A. Y., and Yakovlev, D. G.

Abstract

Neutron stars are relativistic objects. Their structure and evolution should be studied using the General Theory of Relativity. The importance of relativistic effects for a star of mass M and radius R is characterized by the compactness parameterrg/R given by Eq. (1.4), where rg is the Schwarzschild radius. Typically, one has rg/R ∼ 0.2 − 0.4 for a neutron star, whereas rg/R ≪ 1 for all other stars. For instance, rg/R ∼ 10-4 for white dwarfs and rg/R ∼ 10−6 for main-sequence stars of M ≃ M⊙. [ABSTRACT FROM AUTHOR]

Published
2007
Full Text
View/download PDF

30. Envelopes with Strong Magnetic Fields.

Author

Bertola, F., Cassinelli, J.P., Cesarsky, C.J., Ehrenfreund, P., Engvold, O., Heck, A., van den Heuvel, E.P.J., Kaspi, V.M., Kuijpers, J.M.E., van der Laan, H., Murdin, P.G., Pacini, F., Radhakrishnan, V., Somov, B.V., Sunyaev, R.A., Haensel, P., Potekhin, A. Y., and Yakovlev, D. G.

Abstract

Magnetic fields B ≳ 1012 G, typical for isolated neutron stars (§1.3.8), drastically modify many physical properties of the matter. Motion of free electrons and ions perpendicular to the field lines is quantized into Landau orbitals with a characteristic transverse scale equal to the magnetic lengtham = (ħc/eB)1/2. This brings to the scene an atomic field-strength parameter γ = (a0/am)2, where a0 is the Bohr radius. If this parameter is large, the Lorentz force acting on valence electrons in atoms exceeds the Coulomb force. The Landau energy levels of electrons are modified by relativistic effects if the field strength in the relativistic units, (4.1)$$ b = h--\omega _c /(m_e c^2 ) = B/B_r , $$ becomes b ≳ 1. Here, ωc = eB/(mec) is the electron cyclotron frequency and Br = me2}c{3}/(eħ) = 4.414 × 1013 G is often called the relativistic magnetic field. [ABSTRACT FROM AUTHOR]

Published
2007
Full Text
View/download PDF

31. Structure and Equation of State of Neutron Star Crusts.

Author

Bertola, F., Cassinelli, J.P., Cesarsky, C.J., Ehrenfreund, P., Engvold, O., Heck, A., van den Heuvel, E.P.J., Kaspi, V.M., Kuijpers, J.M.E., van der Laan, H., Murdin, P.G., Pacini, F., Radhakrishnan, V., Somov, B.V., Sunyaev, R.A., Haensel, P., Potekhin, A. Y., and Yakovlev, D. G.

Abstract

After discussing the Coulomb properties of neutron star envelopes in Chapter 2, we will mainly focus on the nuclear part of the problem. Following a widespread convention we will often call an entire neutron star envelope as a crust (see a discussion on this point in the introductory part of Chapter 2). [ABSTRACT FROM AUTHOR]

Published
2007
Full Text
View/download PDF

32. Equilibrium Plasma Properties. Outer Envelopes.

Author

Bertola, F., Cassinelli, J.P., Cesarsky, C.J., Ehrenfreund, P., Engvold, O., Heck, A., van den Heuvel, E.P.J., Kaspi, V.M., Kuijpers, J.M.E., van der Laan, H., Murdin, P.G., Pacini, F., Radhakrishnan, V., Somov, B.V., Sunyaev, R.A., Haensel, P., Potekhin, A. Y., and Yakovlev, D. G.

Abstract

After an overall introduction into the neutron star physics, we begin a systematic description of neutron star layers (Fig. 1.2). Chapters 2-4 are devoted to neutron star envelopes. These envelopes are non-uniform. The structure of an envelope for a star with the effective surface temperature ∼ 106 K is schematically shown in Fig. 2.1. We indicate characteristic densities and geometrical depths of interfaces between adjoining layers. One can distinguish the atmosphere, the ocean of ion liquid, followed by solidified layers denoted as the outer and inner crusts. At the bottom of the envelope there may be a mantle containing a liquid crystal of nonspherical nuclei (§3.7.2). These layers are already outlined in §1.3.1 and will be studied in more detail below. The properties of the atmosphere, ocean, and the upper edge of the solidified layer strongly depend on temperature. For the assumed surface temperature ∼ 106 K the internal temperature of a cooling (isolated) star would be ∼ 108 K; the main temperature gradient would occur in the ocean, while deeper layers would be nearly isothermal. When the star cools, the atmosphere and the ocean become thinner. In a sufficiently cold star they may be absent and the solidified matter will extend to the very surface. [ABSTRACT FROM AUTHOR]

Published
2007
Full Text
View/download PDF

34. Three hard X-ray transients: GRO J0422+32, GRS 1716-24, GRS 1009-45. Broad band observations by roentgen-MIR-KVANT observatory

Author

Kaniovsky, A.S, primary, Arefiev, V.A, additional, Aleksandrovich, N.L, additional, Borkous, V.V, additional, Borozdin, K.N, additional, Efremov, V.V, additional, Sunyaev, R.A, additional, Kendziorra, E, additional, Kretschmar, P, additional, Kunz, M, additional, Maisack, M, additional, Staubert, R, additional, Doebereiner, S, additional, Englhauser, J, additional, Pietsch, W, additional, Reppin, C, additional, Truemper, J, additional, Skinner, G.K, additional, Willmore, A.P, additional, Brinkman, A.C, additional, Heise, J, additional, and Jager, R, additional

Published
1997
Full Text
View/download PDF

37. Broad-band X-ray observations of Cir X-1

Author

Maisack, M., primary, Staubert, R., additional, Balucinska-Church, M., additional, Skinner, G., additional, Döbereiner, S., additional, Englhauser, J., additional, Arefev, V.A., additional, Efremov, V.V., additional, and Sunyaev, R.A., additional

Published
1995
Full Text
View/download PDF

41. Two new X-ray transients near the Galactic Centre

Author

in't Zand, J.J.M., primary, Heise, J., additional, Brinkman, A.C., additional, Jager, R., additional, Skinner, G.K., additional, Patterson, T.G., additional, Pan, H.-C., additional, Nottingham, M.R., additional, Willmore, A.P., additional, Al-Emam, O., additional, Sunyaev, R.A., additional, Churazov, E.M., additional, Gilfanov, M.R., additional, and Yamburenko, N.S., additional

Published
1991
Full Text
View/download PDF

42. Imaging of the Galactic Center field by KVANT and GRANAT

Author

Sunyaev, R.A., primary, Churazov, E.M., additional, Gilfanov, M.R., additional, Pavlinsky, M., additional, Grebenev, S., additional, Dekhanov, I., additional, Kuznetsov, A.V., additional, Yamburenko, N.S., additional, Skinner, G.K., additional, Patterson, T.G., additional, Willmore, A.P., additional, Emam, O., additional, Pan, H., additional, Nottingham, M.R., additional, Brinkman, A.C., additional, Heise, J., additional, in't Zand, J.J.M., additional, Jager, R., additional, Ballet, J., additional, Laurent, P., additional, Paul, J., additional, Salotti, L., additional, Natalucci, L., additional, Niel, M., additional, Roques, J.P., additional, and Mandrou, P., additional

Published
1991
Full Text
View/download PDF

44. X/γ-ray observation of the crab pulsar with the sigma telescope

Author

Natalucci, L., primary, Bouchet, L., additional, Denis, M., additional, Goldwurm, A., additional, Laurent, P., additional, Lebrun, F., additional, Mereghetti, S., additional, Salotti, L., additional, Sunyaev, R.A., additional, Stepanov, D., additional, Iounin, S., additional, Tchoulkov, I., additional, Kuznetsov, A., additional, Diachkov, A., additional, Khavenson, N., additional, and Novikov, B., additional

Published
1991
Full Text
View/download PDF

45. First observations with the sigma telescope

Author

Roques, J.P., primary, Mandrou, P., additional, Vedrenne, G., additional, Bouchet, L., additional, Ballet, J., additional, Lambert, A., additional, Paul, J., additional, Salotti, L., additional, Gilfanov, M.R., additional, Sunyaev, R.A., additional, Churazov, E.M., additional, Diachkov, A., additional, Khavenson, N., additional, Kuznetsov, A.V., additional, Stepanov, D., additional, and Yunin, S., additional

Published
1991
Full Text
View/download PDF

46. First gamma-ray burst observations with the sigma telescope

Author

Pelaez, F., primary, Atteia, J.-L., additional, Ballet, J., additional, Cordier, B., additional, Lambert, A., additional, Mena, B., additional, Niel, M., additional, Paul, J., additional, Sunyaev, R.A., additional, Stepanov, D., additional, Iounin, S., additional, Tchoulkov, I., additional, Kuznetsov, A.V., additional, Diachkov, A., additional, Khavenson, N., additional, and Novikov, B., additional

Published
1991
Full Text
View/download PDF

47. The first soft gamma-ray image of the Galactic Centre with arc-min accuracy

Author

Cordier, B., primary, Goldwurm, A., additional, Laurent, P., additional, Lebrun, F., additional, Mandrou, P., additional, Natalucci, L., additional, Roques, J.P., additional, Vedrenne, G., additional, Sunyaev, R.A., additional, Stepanov, D., additional, Iounin, S., additional, Tchoulkov, I., additional, Kuznetsov, A.V., additional, Diachkov, A., additional, Khavenson, N., additional, and Novikov, B., additional

Published
1991
Full Text
View/download PDF

48. The results of the MIR-KVANT in 1987–1989

Author

Sunyaev, R.A., primary, Aref'ev, V., additional, Borozdin, K., additional, Churazov, E.M., additional, Efremov, V., additional, Gilfanov, M.R., additional, Grebenev, S., additional, Kaniovsky, A., additional, Kuznetsov, A.V., additional, Lapshov, I., additional, Yamburenko, N.S., additional, Englhauser, J., additional, Doebereiner, S., additional, Pietsch, W., additional, Reppin, C., additional, Truemper, J., additional, Boer, M., additional, Kendziorra, E., additional, Maisack, M., additional, Mony, B., additional, Staubert, R., additional, Skinner, G.K., additional, Patterson, T.G., additional, Willmore, A.P., additional, Eman, O., additional, Pan, H., additional, Nottingham, M.R., additional, Brinkman, A.C., additional, Heise, J., additional, in't Zand, J.J.M., additional, and Jager, R., additional

Published
1991
Full Text
View/download PDF

Catalog

Books, media, physical & digital resources
See catalog results