Mapping the ionised gas around the luminous QSO HE 1029-1401: evidence for minor merger events?
Abstract
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 (<100 Myr) or a featureless continuum embedded in an old stellar population (10 Gyr) typical for a massive elliptical galaxy. The stellar velocity dispersion of σ* = 320±90 km s-1 and the estimated black hole mass log(MBH/M⊙) = 8.7±0.3 are consistent with the local MBH-σ* 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.
Based on observations made with VIMOS integral field spectrograph mounted on the Melipal VLT telescope at ESO-Paranal Observatory (programme 072.B-0550A; PI: K. Jahnke).- Publication:
-
Astronomy and Astrophysics
- Pub Date:
- September 2010
- DOI:
- 10.1051/0004-6361/201014559
- arXiv:
- arXiv:1005.2959
- Bibcode:
- 2010A&A...519A.115H
- Keywords:
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- galaxies: active;
- galaxies: ISM;
- quasars: emission lines;
- quasars: individual:;
- HE 1029-1401;
- Astrophysics - Cosmology and Nongalactic Astrophysics
- E-Print:
- 13 pages, 13 figures, 1 table, accepted for publication in A&