Mapping the ionised gas around the luminous QSO HE 1029-1401: Evidence for minor merger events?

• Main Authors: Husemann, B, Sánchez, S. F, Wisotzki, L, Jahnke, K, Kupko, D, Nugroho, D, Schramm, M
• Format: Journal Article
• Language: English
• Published: 17-05-2010
• Subjects: Physics - Cosmology and Nongalactic Astrophysics
• DOI: 10.48550/arxiv.1005.2959

We present VIMOS integral field spectroscopy of the brightest radio-quiet QSO
on the southern sky HE 1029-1401 at a redshift of z=0.086. Standard
decomposition techniques for broad-band imaging are extended to integral field
data in order to deblend the QSO and host emission. We perform a tentative
analysis of the stellar continuum finding a young stellar population (<100Myr)
or a featureless continuum embedded in an old stellar population (10Gyr)
typical for a massive elliptical galaxy. The stellar velocity dispersion of
sigma_*=320\pm90 km/s and the estimated black hole mass
log(M_BH/M_sun)=8.7\pm0.3 are consistent with the local M_BH-sigma_* relation
within the errors. For the first time we map the two-dimensional ionised gas
distribution and the gas velocity field around HE 1029-1401. While the stellar
host morphology is purely elliptical we find a highly structured distribution
of ionised gas out to 16 kpc from the QSO. The gas is highly ionised solely by
the QSO radiation and has a significantly lower metallicity than would be
expected for the stellar mass of the host, indicating an external origin of the
gas most likely due to minor mergers. We find a rotating gas disc around the
QSO and a dispersion-dominated non-rotating gas component within the central 3
kpc. At larger distances the velocity field is heavily disturbed, which could
be interpreted as another signature of past minor merger events. Alternatively,
the arc-like structure seen in the ionised gas might also be indicative of a
large-scale expanding bubble, centred on and possibly driven by the active
nucleus.