Hubble Space TelescopeFaint Object Camera Spectroscopy of the Narrow‐Line Region of NGC 4151. I. Gas Kinematics

Abstract

We present the results from a detailed kinematic analysis of both ground-based, and Hubble Space T elescope (HST )/Faint Object Camera long-slit spectroscopy at subarcsecond spatial resolution of the narrow-line region (NLR) of NGC 4151. In agreement with previous work, the extended emission gas (R [ 4A) is found to be in normal rotation in the galactic plane, a behavior that we were able to trace even across the nuclear region, where the gas is strongly disturbed by the interaction with the radio jet and connects smoothly with the large-scale rotation deÐned by the neutral gas emission. The HST data, at spatial resolution, allow us for the Ðrst time truly to isolate the kinematic behavior of the indi-0A .029 vidual clouds in the inner narrow-line region. We Ðnd that, underlying the perturbations introduced by the radio ejecta, the general velocity Ðeld can still be well represented by planar rotation down to a radius of (30 pc), the distance at which the rotation curve has its turnover. The most striking D0A .5 result that emerges from our analysis is that the galaxy potential derived Ðtting the rotation curve changes from a "" dark halo ÏÏ at the extended narrow-line region distances to being dominated by the central mass concentration in the NLR, with an almost Keplerian fallo † in the 1@@ \ R \ 4@@ interval. The observed velocity of the gas at implies a mass of M D 109 within the inner 60 pc. The presence 0A .5 M _ of a turnover in the rotation curve indicates that this central mass concentration is extended. The Ðrst measured velocity point (outside the region saturated by the nucleus) would imply an enclosed mass of D5 ] 107 within (10 pc), which represents an upper limit to any nuclear point mass. M _ R D 0A .15

Subaru High-Dispersion Spectroscopy of the Narrow-Line Region in the Seyfert Galaxy NGC 4151

“…Here we should mention that the resultant aperture for the extraction of the nuclear spectrum is 0>80 Â 1>44, which is rather smaller than the spatial extension of the ionized gas clouds around the nucleus of NGC 4151 (e.g., Heckman & Balick 1983;Unger et al 1987;Hutchings et al 1998Hutchings et al , 1999Winge et al 1999; see also Kaiser et al 2000;Nelson et al 2000;. Although a large part of the NLR emission of NGC 4151 is covered by this adopted aperture since the position angle of the slit is along the direction of the NLR extension (77 ), some ionized gas clouds are missed in our analysis.…”

Kinematics of the Narrow-Line Region in the Seyfert 2 Galaxy Markarian 3

“…Capetti et al (1995) have compared optical and radio measurements of the NLR of Mrk 3 and concluded that the NLR clouds are the result of radio jet plasma expanding away from the bicone axis. Winge et al (1997Winge et al ( , 1999 postulate gravitational motions for the NLR in NGC 4151. Recently, Crenshaw & Kraemer (2000 and Kaiser et al (2000) have determined radial velocities as a function of position in the NLRs of NGC 1068 and NGC 4151 (the brightest Seyfert 2 and Seyfert 1 galaxies, respectively) with the Space Telescope Imaging Spectrograph (STIS) on the Hubble Space T elescope (HST ).…”

ACTIVE GALACTIC NUCLEUS AND QUASAR SCIENCE WITH APERTURE MASKING INTERFEROMETRY ON THEJAMES WEBB SPACE TELESCOPE

“…How the misalignment occurs, and the structure and dynamics of gas within ∼10 pc (150 mas) remains unknown. Around 10 9 M in gas lives within the central ∼900 mas (60 pc) and ∼5 × 10 7 M within the central ∼150 mas (10 pc; Winge et al 1999). From mid-IR interferometric observations, there is structure on scales of 2.0 ± 0.4 pc (∼30 mas) FWHM Notes.…”