activity
19982003
collaborators

11 papers

astro-ph2003

VSOP Observations of the EGRET Blazar 1633+382

C. C. Cheung, J. S. Ulvestad, W. T. Vestrand +1

Two high-resolution 5 GHz VSOP+VLBA images of the blazar 1633+382 reveal clear morphological change in both the bright inner east-west jet, and in the more diffuse structure furthe…

astro-ph2003

VLBI Imaging of Seyfert Galaxies

James S. Ulvestad

The advent of the Very Long Baseline Array and its phase-referencing capability have enabled milliarcsecond-scale imaging of radio sources at sub-millijansky sensitivity, opening t…

astro-ph2002

Gigahertz-Peaked Spectrum Radio Sources in Nearby Galaxies

N. M. Nagar, A. S. Wilson, H. Falcke +2

There is now strong evidence that many low-luminosity AGNs (LLAGNs) contain accreting massive black holes and that the nuclear radio emission is dominated by parsec-scale jets laun…

astro-ph2001

Testing the Unified Model with an Infrared Selected Sample of Seyferts

H. R. Schmitt, J. S. Ulvestad, R. R. J. Antonucci +3

We present a series of statistical tests using homogeneous data and measurements for a sample of Seyfert galaxies. These galaxies were selected from mostly isotropic properties, th…

astro-ph2001

The Importance of Shocks in the Ionization of the Narrow Line Region of Seyferts

H. R. Schmitt, A. L. Kinney, J. B. Hutchings +2

We discuss the viability of shocks as the principal source of ionization for the Narrow Line Region of Seyfert galaxies. We present the preliminary results of [OIII]5007A and radio…

astro-ph2001

A Flaring Megamaser in Mrk 348

A. B. Peck, H. Falcke, C. Henkel +4

We report new observations of the H2O megamaser in the Seyfert 2 galaxy Mrk 348. Following our initial detection in 2000 March using the Effelsberg 100 m telescope, re-analysis of…