Archive for the ‘Astrophysics’ Category

Nature of the soft x-ray excess in the spectrum of RX J1037.5-5647 December 1st, 2011

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The source responsible for the soft x-ray excess in the emission spectrum of the pulsar RX J1037.5-5647 is associated with
a hot spot on the surface of the neutron star near the base of an accretion column. The intensity of the emission from this
source, however, only undergoes small (on the order of 15%) variations, while the intensity of the hard component varies substantially
with the rotation period of the neutron star. We show that this situation can occur if the angle between the axis of rotation
and the magnetic axis of the neutron star is no more than 8°. The variation in the intensity of the hard component of the
radiation in this case is interpreted in terms of an anisotropy in the directional diagram. In this scenario, the angle of
inclination of the orbit of the binary system is close to 10°.

Content Type Journal ArticlePages 1-6DOI 10.1007/s10511-011-9196-3Authors
N. R. Ikhsanov, Main (Pulkovo) Astronomical Observatory, Russian Academy of Sciences, St. Petersburg, RussiaN. G. Beskrovnaya, Main (Pulkovo) Astronomical Observatory, Russian Academy of Sciences, St. Petersburg, Russia

Journal AstrophysicsOnline ISSN 1573-8191Print ISSN 0571-7256

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Searches for HH objects in star formation regions. VII. Herbig-Haro objects in the region of the nebula GM 2–41 November 28th, 2011

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Five new Herbig-Haro objects (HH 1036–1040) have been discovered in the neighborhood of the nebula GM 2–41 in a region with
an area of 14′ × 14′, at the center of the HII region DR 15 located in the southern periphery of the Cyg OB2 association.
Four of them have a complex structure typical of HH flows. Hydrogen molecular emission is detected in the object HH 1036 using
archived images from the Spitzer telescope. Two new infrared nebulae illuminated by very red young stellar objects are also
found.

Content Type Journal ArticlePages 1-11DOI 10.1007/s10511-011-9200-yAuthors
E. H. Nikoghosyan, V. A. Ambartsumyan Byurakan Astrophysical Observatory, Byurakan, ArmeniaT. Yu. Magakian, V. A. Ambartsumyan Byurakan Astrophysical Observatory, Byurakan, ArmeniaT. A. Movsessian, V. A. Ambartsumyan Byurakan Astrophysical Observatory, Byurakan, Armenia

Journal AstrophysicsOnline ISSN 1573-8191Print ISSN 0571-7256

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The electromagnetic field produced by oscillations of a magnetized incompressible infinitely long cylinder November 28th, 2011

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The oscillations of a magnetized incompressible cylinder with a uniform magnetic field along its axis and the resulting electromagnetic
field are studied. Two types of characteristic oscillations, torsional and Alfvén, are found to exist in the linear approximation.
In the case of an infinite cylinder with torsional oscillations, no electromagnetic field is generated. In the case of Alfvén
oscillations, an electromagnetic field develops around the cylinder with a local flux density that falls off exponentially
with radial distance from the axis of the cylinder and has a time average of zero. The results are interpreted physically.

Content Type Journal ArticlePages 1-23DOI 10.1007/s10511-011-9202-9Authors
G. S. Bisnovatyi-Kogan, Institute of Space Research (IKI), Russian Academy of Sciences, Moscow, RussiaS. V. Pavlov, Moscow Institute of Physics and Technology (State University), Moscow, Russia

Journal AstrophysicsOnline ISSN 1573-8191Print ISSN 0571-7256

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Magnetic field energy as a source of the radio luminosity of quasars November 28th, 2011

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Energy release in the superconducting core of a neutron star as neutron vortices move toward the boundary of the star’s core
and crust is examined. It is shown that the rate of energy release is on the order of 1026-1030 erg/s, or sufficient to provide the radio luminosity of known pulsars. The energy release rates calculated under the assumption
of asymmetric energy release are compared with observational data on the radio luminosity of 575 pulsars.

Content Type Journal ArticlePages 1-8DOI 10.1007/s10511-011-9201-xAuthors
D. M. Sedrakian, Erevan State University, Erevan, ArmeniaM. V. Hayrapetyan, Erevan State University, Erevan, ArmeniaN. S. Ayvazyan, Erevan State University, Erevan, Armenia

Journal AstrophysicsOnline ISSN 1573-8191Print ISSN 0571-7256

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Emission stars in Cyg OB7. new flare stars. III October 5th, 2011

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A continued search for emission objects in three new fields within the association Cyg OB7 yielded eight new emission stars
in one of these fields. No emission stars were detected in the other two fields, apparently because we have come to the boundary
of the T association on this side. Two UV Cet-type flare stars have been detected in this region for the first time.

Content Type Journal ArticlePages 1-7DOI 10.1007/s10511-011-9187-4Authors
N. D. Melikian, V. A. Ambartsumyan Byurakan Astrophysical Observatory, Byurakan, ArmeniaV. S. Tamazian, Ramon Maria Aller Astronomical Observatory, University of Santiago de Compostela, Santiago de Compostela, SpainA. A. Karapetian, V. A. Ambartsumyan Byurakan Astrophysical Observatory, Byurakan, ArmeniaA. L. Samsonyan, V. A. Ambartsumyan Byurakan Astrophysical Observatory, Byurakan, Armenia

Journal AstrophysicsOnline ISSN 1573-8191Print ISSN 0571-7256

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Survey of hα emission from thirty nearby dwarf galaxies September 24th, 2011

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Measurements of the Hα flux from 30 neighboring dwarf galaxies are presented. After correction for absorption, these fluxes
are used to estimate the star formation rate (SFR). The SFR for 18 of the galaxies according to the Hα emission are compared
with estimates of the SFR from FUV magnitudes obtained with the GALEX telescope. These are in good agreement over the range
log[SFR] = [ −3, 0] M
/year.

Content Type Journal ArticlePages 1-18DOI 10.1007/s10511-011-9181-xAuthors
S. S. Kaisin, Special Astrophysical Observatory, Russian Academy of Sciences, Moscow, RussiaI. D. Karachentsev, Special Astrophysical Observatory, Russian Academy of Sciences, Moscow, RussiaE. I. Kaisina, Special Astrophysical Observatory, Russian Academy of Sciences, Moscow, Russia

Journal AstrophysicsOnline ISSN 1573-8191Print ISSN 0571-7256

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Environmental dependence of other properties of main galaxies at fixed luminosity September 24th, 2011

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Using three volume-limited samples of the Sloan Digital Sky Survey Data Release 6 (SDSS DR6), we have investigated how other
properties of galaxies depend on the environment at fixed luminosity. At fixed luminosity, we still observe strong environmental
dependence of g – r color, concentration index, and morphology of galaxies: red, highly concentrated, and early type galaxies
exist preferentially in the densest regions of the universe, while blue, poorly concentrated, and late type galaxies are located
preferentially in low density regions. This shows that luminosity is not fundamental in correlations between galaxy properties
and the environment.

Content Type Journal ArticlePages 1-8DOI 10.1007/s10511-011-9184-7Authors
Xin-Fa Deng, School of Science, Nanchang University, Jiangxi, ChinaYong Xin, School of Science, Nanchang University, Jiangxi, ChinaCheng-Hong Luo, School of Science, Nanchang University, Jiangxi, ChinaPing Wu, School of Science, Nanchang University, Jiangxi, China

Journal AstrophysicsOnline ISSN 1573-8191Print ISSN 0571-7256

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Anomalous flare activity of the blasar 3c 454.3 during 2005–2011 September 24th, 2011

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Anomalous flare phenomena observed in the blasar 3

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New type of extragalactic objects? September 24th, 2011

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We have reported the discovery of a population of the normal extragalactic field galaxies with the clear presence of strong
FHIL (forbidden high by ionized lines) and HeII 4686 emission. In this paper we present a dozen of them extracted from the
SDSS dr7. The high resolution spectra 0.86 Å /px obtained with the 6-m telescope of the Special Astrophysical observatory
of Russia are introduced for one of them, SDSS J093801.63 + 135317.0 confirming the presence of strong and wide FHIL and HeII
4686 emission. These objects show typical narrow (FWHM ~ 120 – 250

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Five supernova survey galaxies in the southern hemisphere. II. the supernova rates September 23rd, 2011

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Based on the database compiled in the first article of this series, with 56 SN events discovered in 3838 galaxies of the southern
hemisphere, we compute the rate of supernovae (SNe) of different types along the Hubble sequence normalized to the optical
and near-infrared luminosities as well as to the stellar mass of the galaxies. We find that the rates of all SN types show
a dependence on both morphology and colors of the galaxies, and therefore, on the star-formation activity. The rate of core-collapse
(CC) SNe is confirmed to be closely related to the Star Formation Rate (SFR) and only indirectly to the total mass of the
galaxies. The rate of SNe Ia can be explained by assuming that at least 15% of Ia events in spiral galaxies originates in
relatively young stellar populations. We find that the rates show no modulation with nuclear activity or environment. The
ratio of SN rates between types Ib/c and II shows no trend with spiral type.

Content Type Journal ArticlePages 1-14DOI 10.1007/s10511-011-9180-yAuthors
A. A. Hakobyan, Byurakan Astrophysical Observatory, Byurakan, ArmeniaA. R. Petrosian, Byurakan Astrophysical Observatory, Byurakan, ArmeniaG. A. Mamon, Institut dˈAstrophysique de Paris, Paris, FranceB. McLean, Space Telescope Science Institute, Baltimore, USAD. Kunth, Institut dˈAstrophysique de Paris, Paris, FranceM. Turatto, INAF – Osservatorio Astronomico di Trieste, Trieste, ItalyE. Cappellaro, INAF – Osservatorio Astronomico di Padova, Padova, ItalyF. Mannucci, INAF – Osservatorio Astrofisico di Arcetri, Arcetri, ItalyR. J. Allen, Space Telescope Science Institute, Baltimore, USAN. Panagia, Space Telescope Science Institute, Baltimore, USAand M. Della Valle, INAF – Osservatorio Astronomico di Capodimonte, Capodimonte, Italy

Journal AstrophysicsOnline ISSN 1573-8191Print ISSN 0571-7256

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