7C

The Astronomical Journal, 137:3718--3729, 2009 March
doi:10.1088/0004-6256/137/3/3718

MOJAVE: MONITORING OF JETS IN ACTIVE GALACTIC NUCLEI WITH VLBA EXPERIMENTS.
V. MULTI-EPOCH VLBA IMAGES

M. L. Lister 1 , H. D. Aller 2 , M. F. Aller 2 , M. H. Cohen 3 , D. C.
Homan 4, M. Kadler 5,6,7,8 , K. I. Kellermann 9 , Y. Y. Kovalev 10,11 ,
E. Ros 10 , T. Savolainen 10 , J. A. Zensus 10 , and R. C. Vermeulen 12

1 Department of Physics, Purdue University, 525 Northwestern Avenue, West Lafayette, IN 47907, USA; mlister@purdue.edu
2 Department of Astronomy, University of Michigan, 817 Denison Building, Ann Arbor, MI 48109-1042, USA; haller@umich.edu, mfa@umich.edu
3 Department of Astronomy, California Institute of Technology, Mail Stop 105-224, Pasadena, CA 91125, USA; mhc@astro.caltech.edu
4 Department of Physics and Astronomy, Denison University, Granville, OH 43023, USA; homand@denison.edu
5 Dr. Remeis-Sternwarte Bamberg, Universite at Erlangen-Nurnberg, Sternwartstrasse 7, 96049 Bamberg, Germany
6 Erlangen Centre for Astroparticle Physics, Erwin-Rommel Str. 1, 91058 Erlangen, Germany
7 CRESST/NASA Goddard Space Flight Center, Greenbelt, MD 20771, USA
8 Universities Space Research Association, 10211 Wincopin Circle, Suite 500, Columbia, MD 21044, USA; matthias.kadler@sternwarte.uni5erlangen.de
9 National Radio Astronomy Observatory, 520 Edgemont Road, Charlottesville, VA 22903­2475, USA; kkellerm@nrao.edu
10 Max-Planck-Institut fur Radioastronomie, Auf dem Hugel 69, D-53121 Bonn, Germany; ros@mpifr-bonn.mpg.de, tsavolainen@mpifr-bonn.mpg.de,
azensus@mpifr-bonn.mpg.de
11 Astro Space Center of Lebedev Physical Institute, Profsoyuznaya 84/32, 117997 Moscow, Russia; ykovalev@mpifr-bonn.mpg.de
12 ASTRON, Postbus 2, NL-7990 AA Dwingeloo, Netherlands; rvermeulen@astron.nl
Received 2008 October 24; accepted 2008 December 18; published 2009 February 25


ABSTRACT

We present images from a long-term program (MOJAVE: Monitoring of Jets in
active galactic nuclei (AGNs) with VLBA Experiments) to survey the structure
and evolution of parsec-scale jet phenomena associated with
bright radio-loud active galaxies in the northern sky.
The observations consist of 2424 15 GHz Very Long
Baseline Array (VLBA) images of a complete flux-density-limited sample
of 135 AGNs above declination -20deg , spanning the period 1994 August to 2007
September. These data were acquired as part of the MOJAVE
and 2 cm Survey programs, and from the VLBA archive.
The sample-selection criteria are based on multi-
epoch parsec-scale (VLBA) flux density, and heavily favor highly variable
and compact blazars. The sample
includes nearly all the most prominent blazars in the northern sky,
and is well suited for statistical analysis
and comparison with studies at other wavelengths.
Our multi-epoch and stacked-epoch images show 94% of
the sample to have apparent one-sided jet morphologies, most likely
due to the effects of relativistic beaming.
Of the remaining sources, five have two-sided parsec-scale jets, and three
are effectively unresolved by the
VLBA at 15 GHz, with essentially all of the flux density contained within
a few tenths of a milliarcsecond.

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