2-D spectroscopy and modeling of the biconical ionized gas in NGC 4388

Abstract

We present recent results from spectroscopic data and modeling of the biconical ionized gas in the Seyfert-2 galaxy NGC 4388. A field of ~2.6 x 2.4 kpc centered on the nucleus has been observed by means of the modern technique of integral field spectroscopy. The analysis of more than two hundred spectra allowed to study the physical characteristics of the gas in the surroundings of the active nucleus. The South-West ionization cone, revealed by the [O III]5007/H-beta excitation map, shows high emission line ratios not completely supported by simple photoionization. Composite models which account for the combined effects of photoionization and shock show that such high [O III]/H-beta line ratios are emitted by low density (n_0=30 cm^-3) gas inside large (D > 1 pc) shocked clouds (V_s=100 km/s) reached by a relatively low flux from the active nucleus. The data of the VEELR in the North-East cone by Yoshida et al. (2002) have been modeled. The results confirm that photoionization is the prevailing mechanism, but nontheless weak shocks are under way between colliding clouds with small (< 1 pc) sizes and low densities n_0 <= 100 cm^-3, moving outward at relatively low velocities (V_s=100 km/s).

arXiv commentAccepted for publication in Astronomy & Astrophysics

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Cited by in corpus (8)

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• Subaru Deep Spectroscopy of the Very Extended Emission-Line Region of NGC 4388: Ram Pressure Stripped Gas Ionized by the Nuclear Radiation
• The Infrared Continuum of Active Galaxies
• The complex, dusty narrow-line region of NGC 4388: Gas-jet interactions, outflows, and extinction revealed by near-IR spectroscopy
• New photometric and spectroscopic observations of the Seyfert galaxy Mrk 315
• The peculiar galaxy Mkn 298 revisited through integral field spectroscopy
• Distribution of the heavy elements throughout the extended narrow line region of the Seyfert galaxy NGC 7212