RADIO AND EMISSION-LINE JETS IN THE TYPE-2 SEYFERT-GALAXY MARKARIAN-1066 (UGC-2456)

Citation
G. Bower et al., RADIO AND EMISSION-LINE JETS IN THE TYPE-2 SEYFERT-GALAXY MARKARIAN-1066 (UGC-2456), The Astrophysical journal, 454(1), 1995, pp. 106
Citations number
59
Categorie Soggetti
Astronomy & Astrophysics
Journal title
ISSN journal
0004637X
Volume
454
Issue
1
Year of publication
1995
Part
1
Database
ISI
SICI code
0004-637X(1995)454:1<106:RAEJIT>2.0.ZU;2-4
Abstract
Hubble Space Telescope (HST) images, ground-based spectroscopy, and a new VLA map of the type 2 Seyfert galaxy Markarian 1066 (UGC 2456) are used to study the morphology, kinematics, and excitation of the ioniz ed gas and its relation to the radio continuum source. The H alpha + [ N II] image reveals emission from a region 3'' (490 h(-1) pc, h = H-0/ 100 km s(-1) Mpc(-1)) long centered on the nucleus, while the [O III]- emitting gas is concentrated into a bright ''jetlike'' structure exten ding 1''14 (230 h(-1) pc) NW of the nucleus. Ground-based spectroscopy indicates that both high- and low-excitation components are present i n the narrow-line region. The low-excitation emission lines have ratio s similar to those of LINERs, trace out a rotation curve with amplitud e approximate to 200 km s(-1), and probably originate from gas in the galaxy disk. However, relative to this rotation curve, the CO mi-emitt ing gas is blueshifted NW of the nucleus and redshifted SE of the nucl eus. The VLA 3.6 cm map confirms that the radio source is ''linear'' a nd resembles a bipolar jet. Both the [O III] and H alpha+[N II] distri butions align with the radio axis. The highest excitation gas coincide s with the NW radio jet. High-excitation gas may also be associated wi th the SE radio jet, but its line emission is attenuated by obscuratio n in the foreground galactic disk. We discuss two possible scenarios w hich can account for the observed association between the high-excitat ion gas and the radio jet. A nuclear continuum source could emit ioniz ing photons anisotropically and preferentially along the jet. Alternat ively, shocks may form at the boundary between the jet and ambient clo ud material and generate ionizing photons in situ. The radio and emiss ion-line jets in Mrk 1066 are approximately aligned with the galaxy's bar in projection on the sky. However, an analysis of a volume-limited sample of Seyfert galaxies indicates no strong alignment between kilo parsec scale stellar bars and similar to 100 pc scale radio sources.