Understanding the relationship between the environment of the black hole and the radio jet: optical spectroscopy of compact AGN

We aim to investigate the relationship between radio jet activity on parsec-scales and the characteristics of both the bright active galactic nuclei (AGN) and their broad line regions (BLR). For this purpose, we combine 2cm Very Long Baseline Array observations of AGN with their optical spectral observations. This would enable us to investigate the optical spectra of a set of 172 relativistically beamed, flat-spectrum AGN with the nuclear disk oriented near to the plane of sky. Here, we present first results from optical spectroscopic observations of the brightest AGN from the 2 cm VLBA survey, and show a diversity of their spectral morphologies.Comment: 2 pages, to be published in the Proceedings of "Multiwavelength AGN Surveys", Cozumel, Dec 8 - 12, 200

Radio-optical scrutiny of the central engine in compact AGN

We combine Very-Long-Baseline Interferometry (VLBI) data for $\sim100$ active galactic nuclei (AGN) available from the Very Large Baseline Array (VLBA) 2 cm imaging survey and optical spectroscopy to investigate the relationships in the emission-line region--central engine--radio jet system. Here, we present the diversity of spectral types among the brightest AGN in our sample. We also discuss correlations between the mass of the central engine and properties of the parsec-scale radio jet for 24 AGN selected by the presence of H$\beta$ broad-emission lines in their spectra.Comment: 4 pages, 5 figures, to appear in the proceedings of the Workshop on "Multiband Approach to AGN" held in Bonn (Germany), 30 September - 2 October 2004, to be published in "Memorie della Societa Astronomica Italiana

NGC1052 - A study of the pc-scale twin jet

We present results of a VLBA multi-frequency study of the pc-scale twin jet in NGC1052. We observed this object at epoch 1998.99 with the VLBA at 5, 8.4, 22 and 43 GHz both in total and linearly polarized intensity. The spectral analysis confirms the necessity of a free-free absorbing medium, obscuring the innermost part of both jets. At 5 GHz we found a compact linearly polarized emission region at the base of the eastern jet with a degree of polarization of 1.5%. At higher frequencies there is no evidence for polarization in our data. A core shift analysis constrains the position of the central engine to ~0.03 pc. The shift rates of the apparent core position with frequency confirm the strong influence of free-free absorption in conjunction with steep pressure gradients at the bases of both jets.Comment: Proceedings of the conference "SRT: the impact of large antennas on Radio Astronomy and Space Science", Cagliari, Italy, 7-10 November 2001, in press; 6 pages, 5 figures, needs srt_style.st