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  • 1
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    Outflows of stars due to quasar feedback (2013)
    Oxford University Press
    Details
    Publication Date: 2013-04-03
    Description: Quasar feedback outflows are commonly invoked to drive gas out of galaxies in the early gas-rich epoch to terminate growth of galaxies. Here we present simulations that show that AGN feedback may drive not only gas but also stars out of their host galaxies under certain conditions. The mechanics of this process is as follows: (1) AGN-driven outflows accelerate and compress gas filling the host galaxy; (2) the accelerated dense shells become gravitationally unstable and form stars on radial trajectories. For the spherically symmetric initial conditions explored here, the black hole needs to exceed the host's M mass by a factor of a few to accelerate the shells and the new stars to escape velocities. We discuss potential implications of these effects for the host galaxies: (i) radial mixing of bulge stars with the rest of the host; (ii) contribution of quasar outflows to galactic fountains as sources of high-velocity clouds; (iii) wholesale ejection of hypervelocity stars out of their hosts, giving rise to Type II supernovae on galactic outskirts, and contributing to reionization and metal enrichment of the Universe; (iv) bulge erosion and even complete destruction in extreme cases resulting in overweight or bulgeless SMBHs.
    Print ISSN: 0035-8711
    Electronic ISSN: 1365-2966
    Topics: Physics
    Published by Oxford University Press
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  • 2
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    Discrete sources as the origin of the Galactic X-ray ridge emission (2009)
    Nature Publishing Group (NPG)
    Details
    Publication Date: 2009-05-02
    Description: An unresolved X-ray glow (at energies above a few kiloelectronvolts) was discovered about 25 years ago and found to be coincident with the Galactic disk-the Galactic ridge X-ray emission. This emission has a spectrum characteristic of a approximately 10(8) K optically thin thermal plasma, with a prominent iron emission line at 6.7 keV. The gravitational well of the Galactic disk, however, is far too shallow to confine such a hot interstellar medium; instead, it would flow away at a velocity of a few thousand kilometres per second, exceeding the speed of sound in the gas. To replenish the energy losses requires a source of 10(43) erg s(-1), exceeding by orders of magnitude all plausible energy sources in the Milky Way. An alternative is that the hot plasma is bound to a multitude of faint sources, which is supported by the recently observed similarities in the X-ray and near-infrared surface brightness distributions (the latter traces the Galactic stellar distribution). Here we report that at energies of approximately 6-7 keV, more than 80 per cent of the seemingly diffuse X-ray emission is resolved into discrete sources, probably accreting white dwarfs and coronally active stars.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Revnivtsev, M -- Sazonov, S -- Churazov, E -- Forman, W -- Vikhlinin, A -- Sunyaev, R -- England -- Nature. 2009 Apr 30;458(7242):1142-4. doi: 10.1038/nature07946.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Excellence Cluster Universe, Technische Universitat Munchen, 85748, Garching, Germany. mikej@mpa-garching.mpg.de〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/19407795" target="_blank"〉PubMed〈/a〉
    Print ISSN: 0028-0836
    Electronic ISSN: 1476-4687
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
    Published by Nature Publishing Group (NPG)
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  • 3
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    Cobalt-56 gamma-ray emission lines from the type Ia supernova 2014J (2014)
    Nature Publishing Group (NPG)
    Details
    Publication Date: 2014-08-29
    Description: A type Ia supernova is thought to be a thermonuclear explosion of either a single carbon-oxygen white dwarf or a pair of merging white dwarfs. The explosion fuses a large amount of radioactive (56)Ni (refs 1-3). After the explosion, the decay chain from (56)Ni to (56)Co to (56)Fe generates gamma-ray photons, which are reprocessed in the expanding ejecta and give rise to powerful optical emission. Here we report the detection of (56)Co lines at energies of 847 and 1,238 kiloelectronvolts and a gamma-ray continuum in the 200-400 kiloelectronvolt band from the type Ia supernova 2014J in the nearby galaxy M82. The line fluxes suggest that about 0.6 +/- 0.1 solar masses of radioactive (56)Ni were synthesized during the explosion. The line broadening gives a characteristic mass-weighted ejecta expansion velocity of 10,000 +/- 3,000 kilometres per second. The observed gamma-ray properties are in broad agreement with the canonical model of an explosion of a white dwarf just massive enough to be unstable to gravitational collapse, but do not exclude merger scenarios that fuse comparable amounts of (56)Ni.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Churazov, E -- Sunyaev, R -- Isern, J -- Knodlseder, J -- Jean, P -- Lebrun, F -- Chugai, N -- Grebenev, S -- Bravo, E -- Sazonov, S -- Renaud, M -- England -- Nature. 2014 Aug 28;512(7515):406-8. doi: 10.1038/nature13672.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉1] Space Research Institute (IKI), Profsouznaya 84/32, Moscow 117997, Russia [2] Max Planck Institute for Astrophysics, Karl-Schwarzschild-Strasse 1, 85741 Garching, Germany. ; Institute for Space Sciences (ICE-CSIC/IEEC), 08193 Bellaterra, Spain. ; 1] Universite de Toulouse, UPS-OMP, IRAP, Toulouse, France [2] CNRS, IRAP, 9 Avenue colonel Roche, BP 44346, F-31028 Toulouse Cedex 4, France. ; APC, Universite Paris Diderot, CNRS/IN2P3, CEA/Irfu, Observatoire de Paris, Sorbonne Paris Cite, 75205 Paris Cedex 13, France. ; Institute of Astronomy of the Russian Academy of Sciences, 48 Pyatnitskaya Street, 119017 Moscow, Russia. ; Space Research Institute (IKI), Profsouznaya 84/32, Moscow 117997, Russia. ; ETSAV, Universitat Politecnica de Catalunya, Carrer Pere Serra 1-15, 08173 Sant Cugat del Valles, Spain. ; 1] Space Research Institute (IKI), Profsouznaya 84/32, Moscow 117997, Russia [2] Moscow Institute of Physics and Technology, Institutsky pereulok 9, 141700 Dolgoprudny, Russia. ; LUPM, Universite Montpellier 2, CNRS/IN2P3, CC 72, Place Eugene Bataillon, F-34095 Montpellier Cedex 5, France.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/25164750" target="_blank"〉PubMed〈/a〉
    Print ISSN: 0028-0836
    Electronic ISSN: 1476-4687
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
    Published by Nature Publishing Group (NPG)
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  • 4
    Electronic Resource
    Electronic Resource
    Thermalization of neutrons on cold atoms in magnetic traps (1999)
    Springer
    JETP letters 70 (1999), S. 575-577 
    Details
    ISSN: 1090-6487
    Keywords: 28.20.Cz
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract A new method is proposed for cooling polarized neutrons by thermalizing neutrons in spherical and torroidal magnetic traps with elastic triplet scattering by cold, double spin-polarized, hydrogen atoms.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1134/1.568217
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  • 5
    Electronic Resource
    Electronic Resource
    Repopulation of equidistant levels by two coherent resonant phase-shifted electromagnetic fields (2000)
    Springer
    JETP letters 72 (2000), S. 171-173 
    Details
    ISSN: 1090-6487
    Keywords: 32.80.Bx ; 71.70.Jp ; 42.50.−p
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract A new method of atomic and nuclear orientation and polarization is suggested. The method is based on the use of two coherent resonant phase-shifted monochromatic electromagnetic waves. It is demonstrated that a profound phase-shift-dependent level repopulation can be accomplished in a pulsed mode at room temperature. The possible application of this effect to quantum computers is briefly discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1134/1.1320105
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  • 6
    Electronic Resource
    Electronic Resource
    Coherent repopulation of the components of a three-level quantum system in the field of a pulsed bichromatic radio frequency wave (1998)
    Springer
    Journal of experimental and theoretical physics 86 (1998), S. 644-649 
    Details
    ISSN: 1090-6509
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract The coherent repopulation of a quantum system consisting of three nonequidistant levels in the field of a resonant bichromatic rf wave is studied. The atoms are assumed to have an impulsive interaction with the rf wave in which the pulse duration is less than any of the relaxation times. The hyperfine structure of gas atoms and a system of atomic oscillator levels in a magnetic trap are considered as examples of such a quantum system. It is shown that in the second case, the coherent repopulation effect can be used to cool neutral atoms in magnetic traps.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1134/1.558520
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  • 7
    Electronic Resource
    Electronic Resource
    Primary acoustic echo during excitation of a paramagnetic crystal by picosecond elastic video pulses (1999)
    Springer
    Physics of the solid state 41 (1999), S. 560-564 
    Details
    ISSN: 1063-7834
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract The primary acoustic echo formed during excitation of a paramagnetic crystal with effective spin S=1 by two transverse picosecond elastic video pulses is investigated theoretically. Both exciting video pulses are applied perpendicular to the external magnetic field. It is shown that the primary acoustic echo in the general case consists of six longitudinal and transverse signals at the frequencies of the transitions within a Zeeman triplet. The optimal parameters of the exciting video pulses for the appearance of different echo signals are determined.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1134/1.1130824
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  • 8
    Electronic Resource
    Electronic Resource
    Nonlinear propagation of optical pulses of a few oscillations duration in dielectric media (1997)
    Springer
    Journal of experimental and theoretical physics 84 (1997), S. 221-228 
    Details
    ISSN: 1090-6509
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract Using a semi-phenomenological model of the polarization response of an isotropic solid dielectric that does not resort to the slowly-varying-envelope approximation, we have obtained a nonlinear wave equation for the electric field of a femtosecond light pulse propagating in the given dielectric. Evidence is presented that this equation possesses breatherlike solutions in the region of anomalous group dispersion and does not have any solutions in the form of steady-state traveling solitary video pulses. A universal relation is found linking the minimum possible duration of a breatherlike pulse with the medium parameters. It is shown that such a pulse contains roughly one and a half periods of the light-wave.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1134/1.558109
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  • 9
    Electronic Resource
    Electronic Resource
    Coherent repopulation of hyperfine structure levels in the field of a bichromatic resonant radio-frequency wave (1997)
    Springer
    Journal of experimental and theoretical physics 84 (1997), S. 682-686 
    Details
    ISSN: 1090-6509
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract We consider the resonant interaction between atoms with hyperfine energy levels and a bichromatic radio-frequency field. Nuclear Zeeman levels of an impurity center in a magnetic host form a structure of this kind. Using the spin-density-matrix formalism, we solve the problem of coherent repopulation of a system of three of these levels under the action of a bichromatic resonant radio-frequency wave, taking into account transverse relaxation, and note the connection between this effect and the well-known phenomenon of coherent population capture when a laser bichromatic field interacts resonantly with a three-level system. We discuss various possibilities for observation of this effect experimentally.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1134/1.558201
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  • 10
    Electronic Resource
    Electronic Resource
    Self-induced transparency for ultrashort pulses propagating in a multilevel quantum medium (1998)
    Springer
    Journal of experimental and theoretical physics 87 (1998), S. 864-874 
    Details
    ISSN: 1090-6509
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract We study theoretically the phenomenon of self-induced transparency for ultrashort pulses (videopulses) propagating in a multilevel quantum medium under conditions in which the method of slowly varying amplitudes and phases breaks down and the pulse spectrum substantially overlaps the quantum transitions. A special class of transitions with one common level is considered. We find that the dynamics of the videopulses in such a medium is described by a double sine-Gordon equation. We establish the conditions under which steady-state traveling 0π-, 2π-, and 4π-videosolitons are formed. It is found that 4π-videosolitons can propagate both in equilibrium media and in some nonequilibrium media, while 0π-videosolitons can propagate only in nonequilibrium media. We study amplification processes in highly nonequilibrium systems and show that, depending on the initial state of the medium, 2π-and qπ-pulses (0〈q〈1) with increasing amplitudes may be formed. We conclude that the amplification of an ultrashort pulse occurs due to an increase in the photon number density and to an increase in the frequency of each photon. Finally, we study the possibility of an electromagnetic autosoliton being formed in a nonequilibrium dissipative medium.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1134/1.558734
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