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We present the results of the flux density measurements at 4.85 GHz and 10.45 GHz of a sample of 5998 NVSS radio sources with the Effelsberg 100 m telescope. The initial motivation was the need to identify the NVSS radio sources that could…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-13 E. Angelakis , A. Kraus , A. C. S. Readhead , J. A. Zensus , R. Bustos , T. P. Krichbaum , A. Witzel , T. J. Pearson

We present results from a large global VLBI(Very Long Baseline Interferometry) survey of compact radio sources at 86 GHz which started in October 2001. The main goal of the survey is to increase the total number of objects accessible for…

Astrophysics · Physics 2009-04-14 S. Lee , A. P. Lobanov , T. P. Krichbaum , A. Witzel , J. A. Zensus , M. Bremer , A. Greve , M. Grewing

We review the observations of rapid flux density variations in compact radio sources, and discuss the inverse Compton limit to the maximum brightness temperature of incoherent synchrotron sources in comparison with recent VLBA observations.…

Astrophysics · Physics 2007-05-23 K. I. Kellermann

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…

Instrumentation and Methods for Astrophysics · Physics 2023-01-04 John Morgan , Rajan Chhetri , Ron Ekers

We present multiwavelength studies of a transient X-ray source, XMMSL1 J131952.3+225958, associated with the galaxy NGC 5092 at $z=0.023$ detected in the XMM-Newton SLew survey (XMMSL). The source brightened in the 0.2--2 keV band by a…

High Energy Astrophysical Phenomena · Physics 2020-03-23 Dongyue Li , R. D. Saxton , Weimin Yuan , Luming Sun , He-Yang Liu , Ning Jiang , Huaqing Cheng , Hongyan Zhou , S. Komossa , Chichuan Jin

We report on the first wide-field, very long baseline interferometry (VLBI) survey at 90 cm. The survey area consists of two overlapping 28 deg^2 fields centred on the quasar J0226+3421 and the gravitational lens B0218+357. A total of 618…

Astrophysics · Physics 2009-11-13 Emil Lenc , Mike A. Garrett , Olaf Wucknitz , James M. Anderson , Steven J. Tingay

The compact radio source Sgr\,A*, associated with the super massive black hole at the center of the Galaxy, has been studied with VLBA observations at 3 frequencies (22, 43, 86\,GHz) performed on 10 consecutive days in May 2007. The total…

Astrophysics of Galaxies · Physics 2015-05-20 R. -S. Lu , T. P. Krichbaum , A. Eckart , S. König , D. ~Kunneriath , G. Witzel , A. Witzel , J. A. Zensus

We studied the energy spectrum and the large-scale fluctuation of the X-ray background with the ASCA GIS based on the ASCA MSS and LSS observations. A total of 91 fields with Galactic latitude |b|>10 deg were selected with a sky coverage of…

We have discovered an ultrasoft X-ray transient source, 2XMMi J184725.1-631724, which was detected serendipitously in two XMM-Newton observations in the direction of the center of the galaxy IC 4765-f01-1504 at a redshift of 0.0353. These…

High Energy Astrophysical Phenomena · Physics 2015-05-28 Dacheng Lin , Eleazar R. Carrasco , Dirk Grupe , Natalie A. Webb , Didier Barret , Sean A. Farrell

We present the results of a search of infrared excess candidates in a comprehensive (29\,000 stars) magnitude limited sample of dwarf stars, spanning the spectral range F2-K0, and brighter than V$=$15 mag. We searched the sample within the…

Solar and Stellar Astrophysics · Physics 2015-06-17 Fernando Cruz-Saenz de Miera , Miguel Chavez , Emanuele Bertone , Olga Vega

We present new sub-arcsecond-resolution Karl G. Jansky Very Large Array (VLA) imaging at 10 GHz of 155 ultra-luminous ($L_{\rm bol}\sim10^{11.7-14.2} L_\odot$) and heavily obscured quasars with redshifts $z \sim0.4-3$. The sample was…

Intergalactic scintillation of distant quasars is sensitive to free electrons and therefore complements Ly$\alpha$ absorption line experiments probing the neutral intergalactic medium (IGM). We present a new scheme to compute IGM refractive…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-16 A. Pallottini , A. Ferrara , C. Evoli

We present here the discovery of rapid, large amplitude intraday variability in the compact flat-spectrum radio quasar 1156+295. The detection of 40% flux density variations at 15 GHz on a timescale of only 2.7 hours was serendipitously…

Astrophysics · Physics 2009-04-14 T. Savolainen , Y. Y. Kovalev

We have used VSOP space very long baseline interferometry observations to measure the brightness temperature distribution of a well-defined sub-set of the Pearson-Readhead sample of extragalactic radio sources. VLBI which is restricted to…

Astrophysics · Physics 2009-11-06 S. J. Tingay

Using three epochs of VLA observations of the Galactic Plane in the first quadrant taken ~15 years apart, we have conducted a search for a population of variable Galactic radio emitters in the flux density range 1-100 mJy at 6 cm. We find…

Astrophysics of Galaxies · Physics 2015-05-18 Robert H. Becker , David J. Helfand , Richard L. White , Deanne D. Proctor

Interplanetary scintillation observations of 48 of the 55 Augusto et al. (1998) flat spectrum radio sources were carried out at 111 MHz using the interplanetary scintillation method on the Large Phased Array (LPA) in Russia. Due to the…

Astrophysics · Physics 2009-11-11 S. A. Tyul'bashev , A. Pedro

The Red MSX Source (RMS) survey is a multi-wavelength programme of follow-up observations designed to distinguish between genuine massive young stellar objects (MYSOs) and other embedded or dusty objects, such as ultra compact (UC) HII…

Astrophysics · Physics 2007-05-23 J. C. Mottram , J. S. Urquhart , M. G. Hoare , S. L. Lumsden , R. D. Oudmaijer

We make predictions for the cosmological surveys to be conducted by MIPS/SIRTF at 24, 70 and 160 microns, for the GTO and the legacy programs, using the latest knowledge of the instrument. In addition to detector and cirrus confusion noise,…

Astrophysics · Physics 2008-11-26 H. Dole , G. Lagache , J. -L. Puget , .

We show that surface waves along interstellar current sheets closely aligned with the line of sight lead to pulsar scintillation properties consistent with those observed. This mechanism naturally produces the length and density scales of…

Astrophysics of Galaxies · Physics 2015-06-15 Ue-Li Pen , Yuri Levin

The VVV microlensing search has recently surveyed the region of the Galactic plane at b=0 within -10.00 < l < 10.44 deg. in the near-infrared (IR), discovering hundreds of microlensing events. In this paper we explore the microlensing…

Solar and Stellar Astrophysics · Physics 2020-10-14 Maria Gabriela Navarro , Dante Minniti , Rodrigo Contreras Ramos