Multifrequency 3-Year Bi-Monthly Polarization Monitoring of 15 Blazars
Note: All images, movies, and figures presented here are copyrighted by Svetlana Jorstad et al. Any use of these images (other than viewing) requires written permission by the authors. Send such requests to Alan Marscher.
Svetlana Jorstad and Alan Marscher of the BU blazar group perform bimonthly polarimetric observations of blazars (actually, two are radio galaxies with blazar-like radio jets) at high frequencies. The focus of the project is a three-year (1998-2001) VLBA monitoring program of the total and polarized intensity structure of the compact jets of a sample of 15 quasars, BL Lac objects, and radio galaxies. Supplementing the imaging at a resolution of 0.15 mas are 230 and 350 GHz (JCMT) as well as less frequent, essentially simultaneous optical (Steward Observatory) and 90 GHz (BIMA) observations of the polarization (integrated over the entire source).
Collaborators: Timothy Cawthorne and Alastair Stirling (U. Central Lancashire, England), Jason Stevens (Royal Observatory Edinburgh, Scotland), Matthew Lister (National Radio Astronomy Observatory, now at Purdue Univ.), Walter Gear (Cardiff University, Wales), Jose Luis Gomez (IAA, Granada, Spain), Paul Smith (Steward Observatory), J. Richard Forster (U. Cal. Berkeley), Denise Gabuzda (University of Cork, Ireland), and Ian Robson (Royal Observatory Edinburgh)
Download data tables (format: ascii files)
The first paper, Jorstad et al. (2005), a thorough discussion mainly of the VLBA images and their implications, appeared in the October 2005 issue of the Astronomical Journal (vol. 130, p. 1418). We have available either a PDF file (about 11 Mbytes) or a gzip'd Postscript file (about 5.5 Mbytes), although for the actual published version you need to download the paper from the Astronomical Journal website.
Svetlana has made some movies by interpolating the VLBA images using the IDL software package. You can view complete movies for 3C 279 and PKS 1510-089 (ready after Jan. 26, 2002). These include X-ray and optical (3c 279) or radio (PKS 1510-089) light curves but not the JCMT and optical polarization. You can also view movies of the VLBA observations with JCMT and optical polarization for the first year only (March 1998 to February 1999) for 3C 66A, CTA 102, and 3C 454.3.
You can also view the sequences of images for each object by clicking on the source name below. In order to avoid extremely slow operations, these are .gif files that are neither as aesthetic nor as informative as are the Postscript files that Svetlana made. I put the latter into Powerpoint and converted it to html. The resulting output, listed as "alternate images," will look good on certain browsers, perhaps only the newer ones displayed on screens with high resolution, so the images may or may not look nicer on your browser than the .gif images do.
3C 66A (0219+428) (BL Lac object) Alternate images
3C 111 (radio galaxy) Alternate images
0420-014 (quasar) Alternate images
3C 120 (radio galaxy) Alternate images (see also 3C 120 page with updated images and results from a previous study by Gomez et al.)
PKS 0528+134 (quasar) Alternate images
OJ 287 (BL Lac object; images + plot) Alternate images
3C 273 (quasar) Alternate images
3C 279 (quasar; images + plots) Alternate images
PKS 1510-089 (quasar) Alternate images
3C 345 (quasar) Alternate images
1803+784 (BL Lac object) Alternate images
1823+568 (BL Lac object) Alternate images
BL Lac (BL Lac object, obviously!) Alternate images
CTA 102 (quasar; images + plot) Alternate images
3C 454.3 (quasar; images + plots) Alternate images