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相关论文: Interstellar scintillation is an indicator of astr…

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We have conducted the first systematic search for interday variability in a large sample of extragalactic radio sources at 15 GHz. From the sample of 1158 radio-selected blazars monitored over a $\sim$10 year span by the Owens Valley Radio…

Intraday Variability of compact extragalactic radio sources can be interpreted as quenched scintillation due to turbulent density fluctuations of the nearby ionized interstellar medium. We demonstrate that the statistical analysis of IDV…

天体物理学 · 物理学 2007-05-23 T. Beckert , L. Fuhrmann , G. Cimo , T. P. Krichbaum , A. Witzel , J. A. Zensus

We use VLBA+VLA observations to measure the sizes of the scatter-broadened images of 6 of the most heavily scattered known pulsars: 3 within the Galactic Centre (GC) and 3 elsewhere in the inner Galactic plane. By combining the measured…

X-rays trace accretion onto compact objects in binaries with low mass companions at rates ranging up to near Eddington. Accretion at high rates onto neutron stars goes through cycles with time-scales of days to months. At lower average…

天体物理学 · 物理学 2009-11-06 Jean H. Swank

We have used the University of Tasmania's 30 m radio telescope at Ceduna in South Australia to regularly monitor the flux density of a number of southern blazars. We report the detection of an annual cycle in the variability timescale of…

宇宙学与河外天体物理 · 物理学 2015-05-13 Steven J. B. Carter , Simon P. Ellingsen , Jean-Pierre Macquart , James E. J. Lovell

We introduce a rigorous and general framework to study systematically self-gravitating elastic materials within general relativity, and apply it to investigate the existence and viability, including radial stability, of spherically…

广义相对论与量子宇宙学 · 物理学 2022-06-07 Artur Alho , José Natário , Paolo Pani , Guilherme Raposo

We present here the results from an extensive scintillation study of twenty pulsars in the dispersion measure (DM) range 3 - 35 pc cm^-3 carried out using the Ooty Radio Telescope, to investigate the distribution of ionized material in the…

天体物理学 · 物理学 2009-10-30 N. D. Ramesh Bhat , Yashwant Gupta , A. Pramesh Rao

Four close radio sources in the International Celestial Reference Frame (ICRF) catalog were observed using phase referencing with the VLBA at 43, 23 and 8.6 GHz, and with VERA at 23 GHz over a one year period. The goal was to determine the…

宇宙学与河外天体物理 · 物理学 2015-05-20 Ed Fomalont , Kenneth Johnston , Alan Fey , Dave Boboltz , Tamoaki Oyama , Mareki Honma

We study inhomogeneous multidimensional cosmological models with a higher dimensional space-time manifold under dimensional reduction. Stability due to different types of effective potentials is analyzed for specific configurations of…

广义相对论与量子宇宙学 · 物理学 2011-04-15 U. Guenther , A. Zhuk

Scintillation noise is a major limitation of ground base photometric precision. An extensive dataset of stellar scintillation collected at 11 astronomical sites world-wide with MASS instruments was used to estimate the scintillation noise…

天体物理仪器与方法 · 物理学 2015-06-11 V. Kornilov , M. Sarazin , A. Tokovinin , T. Travouillon , O. Voziakova

In a companion paper, we have conducted an in-depth analysis of radial velocity jitter of over 600 stars, examining the astrophysical origins including stellar granulation, oscillation, and magnetic activity. In this paper, we highlight a…

地球与行星天体物理 · 物理学 2020-04-30 Jacob K. Luhn , Jason T. Wright , Howard Isaacson

We present a catalogue of over 7000 sources from the GLEAM survey which have significant structure on sub-arcsecond scales at 162MHz. The compact nature of these sources was detected and quantified via their Interplanetary Scintillation…

天体物理仪器与方法 · 物理学 2023-01-04 John Morgan , Rajan Chhetri , Ron Ekers

We present the results of 5-GHz observations with the VLA A-array of a sample of candidate Compact Steep Spectrum sources (CSSs) selected from the S4 survey. We also estimate the symmetry parameters of high-luminosity CSSs selected from…

天体物理学 · 物理学 2009-10-31 D. J. Saikia , S. Jeyakumar , C. J. Salter , P. Thomasson , R. E. Spencer , F. Mantovani

Short time-scale radio variations of compact extragalactic radio sources, known as IntraDay Variability, can be explained in at least some sources by a source-extrinsic effect, in which the variations are interpreted as scintillation of…

We describe a compact and stable setup for detecting the optical second harmonics, in which the incident plane rotates with respect to the sample. The setup is composed of rotating Fresnel-rhomb optics and a femtosecond ytterbium-doped…

仪器与探测器 · 物理学 2021-04-23 S. H. Kim , S. Jung , B. Seok , Y. S. Kim , H. Park , T. Otsu , Y. Kobayashi , C. Kim , Y. Ishida

Observations of Interplanetary Scintillation (IPS) are an efficient remote-sensing method to study the solar wind and inner heliosphere. From 2016 to 2018, some distinctive observations of IPS sources like 3C 286 and 3C 279 were…

空间物理 · 物理学 2021-05-26 Li-Jia Liu , Bo Peng , Lei Yu , Ye-Zhao Yu , Ji-Guang Lu , Bin Liu , O. Chang , M. M. Bisi , FAST Collaboration

Gaia's very accurate astrometric measurements will allow the International Celestial Reference Frame (ICRF) to be improved by a few orders of magnitude in the optical. Several sets of quasars are used to define a kinematically stable…

天体物理仪器与方法 · 物理学 2016-06-03 R. K. Bachchan , D. Hobbs , L. Lindegren

The presented thesis is devoted to the study of instabilities of compact objects within the Einstein-Gauss-Bonnet theory. This theory includes higher-order corrections in curvature, which are inspired by the low energy limit of string…

高能物理 - 理论 · 物理学 2019-12-19 M. A. Cuyubamba

The RadioAstron space radio telescope provides a unique opportunity to study the extreme brightness temperatures ($\mathrm{T_B }$) in AGNs with unprecedented long baselines of up to 28 Earth diameters. Since interstellar scintillation (ISS)…

We study the system constructed by charged scalar fields linearly coupled to asymptotically flat horizonless compact reflecting stars. We obtain bounds on the charge of the scalar field, below which the scalar hairy star is expected to…

广义相对论与量子宇宙学 · 物理学 2018-11-05 Yan Peng