Parsec-Scale Blazar Monitoring: Proper Motions

Thumbnail Image

Files

Homan_2001_ApJ_549_840.pdf (1.36 MB)

Links to Files

https://iopscience.iop.org/article/10.1086/319466

Permanent Link

https://doi.org/10.1086%2F319466
 http://hdl.handle.net/11603/18235
 http://simbad.u-strasbg.fr/simbad/sim-ref?querymethod=bib&simbo=on&submit=submit+bibcode&bibcode=2001ApJ...549..840H
 https://ned.ipac.caltech.edu/cgi-bin/objsearch?search_type=Search&refcode=2001ApJ...549..840H

Collections

UMBC Physics Department
UMBC Center for Space Sciences and Technology (CSST) / Center for Research and Exploration in Space Sciences & Technology II (CRSST II)

Author/Creator

Author/Creator ORCID

Date

2001-03-10

Type of Work

journal articles
Text

Department

Program

Citation of Original Publication

Daniel C. Homan, Roopesh Ojha, John F. C. Wardle, David H. Roberts, Margo F. Aller, Hugh D. Aller, Philip A. Hughes, Parsec-Scale Blazar Monitoring: Proper Motions, The Astrophysical Journal, Volume 549, Number 2, https://doi.org/10.1086%2F319466

Rights

This item is likely protected under Title 17 of the U.S. Copyright Law. Unless on a Creative Commons license, for uses protected by Copyright Law, contact the copyright holder or the author.
© 2001. The American Astronomical Society. All rights reserved.

Subjects

Abstract

We present proper motions obtained from a dual-frequency, six-epoch, VLBA polarization experiment monitoring a sample of 12 blazars. The observations were made at 15 and 22 GHz at bimonthly intervals over 1996. A total of 10 of the 11 sources for which proper motion could be reliably determined are superluminal. Only J2005+77 has no superluminal components. Three sources (OJ 287, J1224+21, and J1512-09) show motion faster than 10h⁻¹c, requiring γpattern of at least 10h⁻¹ (H0 = 100h km s⁻¹ Mpc⁻¹). We compare our results to those in the literature and find motions outside the previously observed range for four sources. While some jet components exhibit significant nonradial motion, most motion is radial. In at least two sources there are components moving radially at significantly different structural position angles. In five of six sources (3C 120, J1224+21, 3C 273, 3C 279, J1512-09, and J1927+73) that have multiple components with measurable proper motion, the innermost component is significantly slower than the others, suggesting that acceleration occurs in the jet. In the motions of individual components we observe at least one decelerating motion and two "bending" accelerations that tend to align their motions with larger scale structure. We also discuss in detail our procedures for obtaining robust kinematical results from multifrequency VLBI data spanning several epochs.