Dust Obscuration in the Universe

1995 ◽  
Vol 12 (2) ◽  
pp. 146-152 ◽  
Author(s):  
F. J. Masci ◽  
R. L. Webster
Keyword(s):  
Probability Distribution ◽  
Optical Depth ◽  
Dust Content ◽  
Line Of Sight ◽  
Radio Sources ◽  
Complete Sample ◽  
Spectrum Radio ◽  
The Universe

AbstractA substantial population of red quasars has been discovered in a complete sample of flat-spectrum radio sources. Dust is the most likely cause of the reddening in this sample. The location of the dust is poorly known, but may either be in the line-of-sight to the quasar, or in the immediate quasar environment. In this paper we are interested in models where the dust is located in the line of sight to the quasar. We calculate the probability distribution of the optical depth in galactic dust as a function of source redshift, using a range of parameters which might describe real galaxies. We compare these results with those found for our sample of radio quasars. If the dust content is unevolving, then it is not possible to account for all the observed reddening in the quasar sample using these models. Our minimum dust model predicts that 15% of background quasars to z ~ 5 will have a line of sight within 5 kpc of a galaxy’s centre, and would therefore be reddened out of B-band flux-limited samples.

scholarly journals Bulk Relativistic Motion in a Complete Sample of Radio Selected AGN

1987 ◽  
Vol 121 ◽  
pp. 287-293
Author(s):  
C.J. Schalinski ◽  
P. Biermann ◽  
A. Eckart ◽  
K.J. Johnston ◽  
T.Ph. Krichbaum ◽  
...  
Keyword(s):  
Dynamic Range ◽  
Radio Sources ◽  
Relativistic Motion ◽  
Complete Sample ◽  
Superluminal Motion ◽  
Spectrum Radio ◽  
Wide Range ◽  
Show Evidence

A complete sample of 13 flat spectrum radio sources is investigated over a wide range of frequencies and spatial resolutions. SSC-calculations lead to the prediction of bulk relativistic motion in all sources. So far 6 out of 7 sources observed with sufficient dynamic range by means of VLBI show evidence for apparent superluminal motion.

Bulk Relativistic Motion in a Complete Sample of Flat Spectrum Radio Sources

1988 ◽  
pp. 71-72 ◽  
Author(s):  
C. J. Schalinski ◽  
A. Witzel ◽  
Th. P. Krichbaum ◽  
C. A. Hummel ◽  
P. L. Biermann ◽  
...  
Keyword(s):  
Radio Sources ◽  
Relativistic Motion ◽  
Complete Sample ◽  
Spectrum Radio

A Complete Sample of Flat-Spectrum Radio Sources from the Parkes 2.7 GHz Survey

1989 ◽  
pp. 39-40
Author(s):  
Ann Savage ◽  
David L. Jauncey ◽  
Graeme L. White ◽  
Bruce A. Peterson ◽  
W. L. Peters ◽  
...  
Keyword(s):  
Radio Sources ◽  
Complete Sample ◽  
Spectrum Radio

scholarly journals VLBI Morphology of GHz-Peaked Spectrum Radio Galaxies

1994 ◽  
Vol 159 ◽  
pp. 425-425
Author(s):  
D. Dallacasa ◽  
C. Fanti ◽  
R. Fanti
Keyword(s):  
Radio Galaxies ◽  
Radio Sources ◽  
Complete Sample ◽  
Spectrum Radio ◽  
5 Ghz

GHz-Peaked Spectrum (GPS) radio sources are intrinsically small (< 1 kpc) and unbeamed objects. The galaxies considered here (0316+161, 0404+768, 0428+205, 1323+321, 1358+624, 1819+39, 1829+29) have been selected from the Peacock and Wall (1981) catalogue, and belong to a complete sample of Compact Steep-Spectrum (CSS) radio sources (Fanti et al., 1990). Their radio spectra show a turnover which could be explained in terms of synchrotron self-absorption. It occurs at frequencies ranging from about 100 MHz to 5 GHz and for this reason they do not appear in the 3CR catalogue.

Long-term variability of a complete sample of flat-spectrum radio sources at declinations 10°–12°30′ (J2000)

2012 ◽  
Vol 56 (5) ◽  
pp. 345-362 ◽  
Author(s):  
A. G. Gorshkov ◽  
V. K. Konnikova ◽  
M. G. Mingaliev
Keyword(s):  
Radio Sources ◽  
Complete Sample ◽  
Spectrum Radio

scholarly journals A multiwavelength study of a sample of Texas Radio Survey steep spectrum sources

2006 ◽  
Vol 2 (14) ◽  
pp. 610-610
Author(s):  
Ray A. Lucas ◽  
Neal Miller ◽  
Anton M. Koekemoer ◽  
Jeffrey Van Duyne ◽  
Kenneth C. Chambers
Keyword(s):  
Radio Interferometer ◽  
Radio Sources ◽  
Complete Sample ◽  
Spectrum Radio ◽  
Radio Survey

VLA A-array snapshots were obtained of a complete sample of steep-spectrum radio sources from the Texas Radio Interferometer survey. Though similar in sensitivity to the FIRST Survey, our A-array snapshots have better resolution, and are complementary to FIRST. All initial A-array maps are made, and we are comparing them to FIRST.

scholarly journals “Red Blazars”: Evidence Against A Synchrotron Origin

1997 ◽  
Vol 163 ◽  
pp. 764-765
Author(s):  
Frank J. Masci ◽  
Rachel L. Webster
Keyword(s):  
Synchrotron Radiation ◽  
Near Infrared ◽  
Radio Sources ◽  
Complete Sample ◽  
Radiation Mechanism ◽  
Spectrum Radio

AbstractRecently, a substantial population of Blazar-like sources exhibiting sharp near-infrared cutoffs and hence exceedingly reddened optical to near-infrared colours (Bj – K ≿ 6) have been discovered in a complete sample of flat spectrum radio sources (Drinkwater et al. 1996). We argue that such “red” colours cannot be due to a synchrotron radiation mechanism alone.

Long-term variability of a complete sample of flat-spectrum radio sources at declinations of 4°–6° (B1950)

2008 ◽  
Vol 52 (4) ◽  
pp. 278-298 ◽  
Author(s):  
A. G. Gorshkov ◽  
V. K. Konnikova ◽  
M. G. Mingaliev
Keyword(s):  
Radio Sources ◽  
Complete Sample ◽  
Spectrum Radio
Sign in / Sign up

Export Citation Format

Share Document