Extended emission-line regions in low-redshift quasars. Dependence on nuclear spectral properties
Husemann, B.; Wisotzki, L.; Sánchez, S. F.;Jahnke, K.. Extended emission-line regions in low-redshift quasars. Dependence on nuclear spectral properties. Astronomy and Astrophysics. 2008, Vol. Volume 488, Issue 1, 2008, pp.145-149, p. -2008.
Aims. We searched for the presence of extended emission-line regions
(EELRs) around low-redshift QSOs. Methods: We observed a sample of 20
mainly radio-quiet low-redshift quasars (z<0.3) by means of integral
field spectroscopy. After decomposing the extended and nuclear emission
components, we constructed [O III] λ5007 narrow-band images of
the EELR to measure the total flux. From the same data we obtained high
S/N (>50) nuclear spectra to measure properties such as [O
III]/Hβ flux ratios, Fe II equivalent widths and Hβ line
widths. Results: A significant fraction of the quasars (8/20) show a
luminous EELR, with detected linear sizes of several kpc. Whether or not
a QSO has a luminous EELR is strongly related with nuclear properties,
in the sense that an EELR was detected in objects with low Fe II
equivalent width and large Hβ {FWHM}. The EELRs were detected
preferentially in QSOs with larger black hole masses. There is no
discernible relation, however, between EELR detection and QSO luminosity
and Eddington ratio.
Based on observations collected at the Centro Astronómico Hispano
Alemán (CAHA) at Calar Alto, operated jointly by the Max-
Planck-Institut für Astronomie and the Instituto de
Astrofísica de Andalucía (CSIC)
Aims. We searched for the presence of extended emission-line regions
(EELRs) around low-redshift QSOs. Methods: We observed a sample of 20
mainly radio-quiet low-redshift quasars (z<0.3) by means of integral
field spectroscopy. After decomposing the extended and nuclear emission
components, we constructed [O III] λ5007 narrow-band images of
the EELR to measure the total flux. From the same data we obtained high
S/N (>50) nuclear spectra to measure properties such as [O
III]/Hβ flux ratios, Fe II equivalent widths and Hβ line
widths. Results: A significant fraction of the quasars (8/20) show a
luminous EELR, with detected linear sizes of several kpc. Whether or not
a QSO has a luminous EELR is strongly related with nuclear properties,
in the sense that an EELR was detected in objects with low Fe II
equivalent width and large Hβ {FWHM}. The EELRs were detected
preferentially in QSOs with larger black hole masses. There is no
discernible relation, however, between EELR detection and QSO luminosity
and Eddington ratio.
Based on observations collected at the Centro Astronómico Hispano
Alemán (CAHA) at Calar Alto, operated jointly by the Max-
Planck-Institut für Astronomie and the Instituto de
Astrofísica de Andalucía (CSIC)