THE HIGHEST RESOLUTION CHANDRA VIEW OF PHOTOIONIZATION AND JET-CLOUD INTERACTION IN THE NUCLEAR REGION OF NGC 4151

Journal Article · Tue Oct 20 00:00:00 EDT 2009 · Astrophysical Journal

DOI:https://doi.org/10.1088/0004-637X/704/2/1195· OSTI ID:21367372

Junfeng, Wang; Fabbiano, G; Karovska, M; Elvis, M; Risaliti, G; Zezas, A ^[1]

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1. Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States)

We report high resolution imaging of the nucleus of the Seyfert 1 galaxy NGC 4151 obtained with a 50 ks Chandra High Resolution Camera (HRC) observation. The HRC image resolves the emission on spatial scales of 0.''5, approx30 pc, showing an extended X-ray morphology overall consistent with the narrow-line region (NLR) seen in optical line emission. Removal of the bright point-like nuclear source and image deconvolution techniques both reveal X-ray enhancements that closely match the substructures seen in the Hubble Space Telescope [O III] image and prominent knots in the radio jet. We find that most of the NLR clouds in NGC 4151 have [O III]/soft X-ray ratio approx10, despite the distance of the clouds from the nucleus. This ratio is consistent with the values observed in NLRs of some Seyfert 2 galaxies, which indicates a uniform ionization parameter even at large radii and a density decreasing as r {sup -2} as expected for a nuclear wind scenario. The [O III]/X-ray ratios at the location of radio knots show an excess of X-ray emission, suggesting shock heating in addition to photoionization. We examine various mechanisms for the X-ray emission and find that, in contrast to jet-related X-ray emission in more powerful active galactic nucleus, the observed jet parameters in NGC 4151 are inconsistent with synchrotron emission, synchrotron self-Compton, inverse Compton of cosmic microwave background photons or galaxy optical light. Instead, our results favor thermal emission from the interaction between radio outflow and NLR gas clouds as the origin for the X-ray emission associated with the jet. This supports previous claims that frequent jet-interstellar medium interaction may explain why jets in Seyfert galaxies appear small, slow, and thermally dominated, distinct from those kpc-scale jets in the radio galaxies.

• OSTI ID: 21367372
• Journal Information: Astrophysical Journal, Vol. 704, Issue 2; Other Information: DOI: 10.1088/0004-637X/704/2/1195; ISSN 0004-637X
• Country of Publication: United States
• Language: English

Related Subjects

79 ASTROPHYSICS
COSMOLOGY AND ASTRONOMY
CAMERAS
EMISSION
IMAGES
PHOTOIONIZATION
PHOTONS
RADIO GALAXIES
RELICT RADIATION
SEYFERT GALAXIES
SHOCK HEATING
SOFT X RADIATION
SYNCHROTRONS
TELESCOPES
X-RAY GALAXIES
ACCELERATORS
BOSONS
COSMIC RADIO SOURCES
COSMIC RAY SOURCES
COSMIC X-RAY SOURCES
CYCLIC ACCELERATORS
ELECTROMAGNETIC RADIATION
ELEMENTARY PARTICLES
GALAXIES
HEATING
IONIZATION
IONIZING RADIATIONS
MASSLESS PARTICLES
MICROWAVE RADIATION
PLASMA HEATING
RADIATIONS
X RADIATION