相关论文: Compact Structure in FIRST Survey Sources

We present an analysis of the detection fraction and the number counts of radio sources imaged with Very Long Baseline Interferometry (VLBI) at 1.4 GHz as part of the mJIVE-20 survey. From a sample of 24,903 radio sources identified by…

We have selected a field from the VLA FIRST Survey which is typical in all aspects except one: it contains a bright, but extremely compact VLBI calibrator - J1159+291. 127 unresolved FIRST sources with $S_{FIRST}\ge 10$ mJy lie within…

The NRAO Very Long Baseline Array (VLBA) was used at 1.4 GHz to image 20 compact sources in the inner 1-degree radius of the Spitzer VLA First-Look Survey. Twelve sources were detected with the VLBA, with peak flux densities above 2 mJy at…

We present preliminary results from a VLBI survey at $\lambda=6 $cm of a sample of 35 sources with flux densities of 2 - 100 mJy. These sources were selected from the VLA FIRST survey at $\lambda = 20 $cm, in a 3 degree field around the…

Based on the FIRST and SDSS catalogues a flux density limited sample of weak Compact Steep Spectrum (CSS) sources with radio luminosity below 10^26 [W/Hz] at 1.4 GHz has been constructed. Our previous multifrequency observations of CSS…

The FIRST survey, begun over twenty years ago, provides the definitive high-resolution map of the radio sky. This VLA survey reaches a 20cm detection sensitivity of 1 mJy over 10,575 deg**2 largely coincident with the SDSS area. Images and…

According to a generally accepted paradigm, small intrinsic sizes of Compact Steep Spectrum (CSS) radio sources are a direct consequence of their youth, but in later stages of their evolution they are believed to become large-scale sources.…

We have obtained 8.4 GHz VLBA observations of a 31-GHz complete sample of ~100 sources between 10 and 100 mJy. The main goals of these observations are: to determine the angular size, radio spectra and identification for a weak sample of…

Multifrequency VLBA observations of the final group of ten objects in a sample of FIRST-based compact steep spectrum (CSS) sources are presented. The sample was selected to investigate whether objects of this kind could be relics of…

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…

We report early results of an observational campaign targeted on a sample of compact steep spectrum sources selected from the FIRST survey which are significantly weaker than those investigated before. The selection criteria and procedure…

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…

We observed with the VLBA at 2.3 and 8.6 GHz a complete flux-density limited sample of 482 radio sources with declination >+75 degrees brighter than 200 mJy at 1.4 GHz drawn from the NVSS catalog. 34% of the sources show parsec-scale…

The coherent image distortions induced by weak gravitational lensing can be used to measure the power spectrum of density inhomogeneities in the universe. We present our on-going effort to detect this effect with the FIRST radio survey,…

We have used VLBA fringe visibility data obtained at 15 GHz to examine the compact structure in 250 extragalactic radio sources. For 171 sources in our sample, more than half of the total flux density seen by the VLBA remains unresolved on…

We present Karl G. Janksy Very Large Array (VLA) 1.3 cm, 3.6 cm, and 6 cm continuum maps of compact radio sources in the Orion Nebular Cluster. We mosaicked 34 square arcminutes at 1.3 cm, 70 square arcminutes at 3.6 cm and 109 square…

We present a high sensitivity radio continuum survey at 6 and 1.3$\,$cm using the Karl G. Jansky Very Large Array towards a sample of 58 high-mass star forming regions. Our sample was chosen from dust clumps within infrared dark clouds with…

A sample of 123 radio sources that exhibit significant variations at 1.4 GHz on a seven year base-line has been created using FIRST VLA B-array data from 1995 and 2002 on a strip at dec=0 near the south Galactic cap. This sample spans the…

As a step toward investigating the parsec-scale properties of faint extragalactic radio sources, the Very Long Baseline Array (VLBA) was used at 5.0 GHz to obtain phase-referenced images of 76 sources in the NOAO Bootes field. These 76…

Using a deep Australia Telescope Compact Array (ATCA) radio survey covering an area of ~3deg^{2} to a 4\sigma sensitivity of \ge 100 \muJy at 1.4GHz, we study the nature of faint radio galaxies. About 50% of the detected radio sources are…