A panchromatic spatially resolved study of the inner 500 pc of NGC 1052 : II. Gas excitation and kinematics

Abstract

We map the optical and near-infrared (NIR) emission-line flux distributions and kinematics of the inner 320×535 pc2of the elliptical galaxy NGC 1052. The integral field spectra were obtained with the Gemini Telescope using the GMOS-IFU and NIFS instruments, with angular resolutions of 0.88 and 0.1 arcsec in the optical and NIR, respectively. We detect five kinematic components: (1) and (2) two spatially unresolved components: a broad-line region visible inHα, with a full width at half-maximum (FWHM) of~3200 km s−1, and an intermediate broad component seen in the [OIII]λλ4959,5007 doublet; (3) an extended intermediate-widthcomponent with 280 km s−1<FWHM<450 km s−1and centroid velocities up to 400 km s−1,which dominates the flux in our data, attributed either to a bipolar outflow related to the jets,rotation in an eccentric disc or to a combination of a disc and large-scale gas bubbles; (4)and (5) two narrow (FWHM<150 km s−1) components, one visible in [OIII], and anothervisible in the other emission lines, extending beyond the field of view of our data, which is attributed to large-scale shocks. Our results suggest that the ionization within the observed field of view cannot be explained by a single mechanism, with photoionization being the dominant mechanism in the nucleus with a combination of shocks and photoionization responsible forthe extended ionization.