J/A+A/580/A113 A low-luminosity type-1 QSO sample. III. (Tremou+, 2015)
A low-luminosity type-1 QSO sample.
III. Optical spectroscopic properties and activity classification.
Tremou E., Garcia-Marin M., Zuther J., Eckart A., Valencia-Schneider M.,
Vitale M., Shan C.
<Astron. Astrophys., 580, A113-113 (2015)>
=2015A&A...580A.113T 2015A&A...580A.113T (SIMBAD/NED BibCode)
ADC_Keywords: QSOs ; Active gal. nuclei ; Galaxies, Seyfert ; Spectroscopy
Keywords: galaxies: starburst - galaxies: active - galaxies: Seyfert -
quasars: emission lines
Abstract:
We report on the optical spectroscopic analysis of a sample of 99
low-luminosity quasi-stellar objects (LLQSOs) at z≤0.06 base the
Hamburg/ESO QSO Survey (HES). To better relate the low-redshift active
galactic nucleus (AGN) to the QSO population it is important to study
samples of the latter type at a level of detail similar to that of the
low-redshift AGN. Powerful QSOs, however, are absent at low redshifts
due to evolutionary effects and their small space density. Our
understanding of the (distant) QSO population is, therefore,
significantly limited by angular resolution and sensitivity. The
LLQSOs presented here offer the possibility of studying the faint end
of this population at smaller cosmological distances and, therefore,
in greater detail. In comparing two spectroscopic methods, we aim to
establish a reliable activity classification scheme of the LLQSOs
sample. Our goal is to enrich our systematic multiwavelength analysis
of the AGN/starburst relation in these systems and give a
complementary information on this particular sample of LLQSOs from the
Hamburg ESO survey. Here, we present results of the analysis of
visible wavelength spectroscopy provided by the HES and the 6 Degree
Field Galaxy Survey (6dFGS). These surveys use different spectroscopic
techniques, long-slit and circular fiber, respectively. These allow us
to assess the influence of different apertures on the activity of the
LLQSOs using classical optical diagnostic diagrams. We perform a
Gaussian fitting of strong optical emission lines and decompose narrow
and broad Balmer components. A small number of our LLQSO present no
broad component, which is likely to be present but buried in the
noise. Two sources show double broad components, whereas six comply
with the classic NLS1 requirements. As expected in NLR of broad line
AGNs, the [SII]-based electron density values range between 100 and
1000Ne/cm3. Using the optical characteristics of Populations A and
B, we find that 50% of our sources with Hβ broad emission are
consistent with the radio-quiet sources definition. The remaining
sources could be interpreted as low-luminosity radio-loud quasar. The
BPT-based classification renders an AGN/Seyfert activity between 50 to
60%. For the remaining sources, the possible starburst contribution
might control the LINER and HII classification. Finally, we discuss
the aperture effect as responsible for the differences found between
data sets, although variability in the BLR could play a significant
role as well.
Description:
The optical spectroscopic analysis of the LLQSO sample is based on two
sets of observations. The first data set is from the HES (Reimers et
al., 1996A&AS..115..235R 1996A&AS..115..235R, Cat. J/A+AS/115/235), in which follow-up
observations were carried out to confirm the type-1 character of the
survey candidates spectroscopically. In addition to this, we have used
data from the 6 Degree Field Galaxy survey (6dFGS), an optical
spectroscopy public database (Jones et al., 2004MNRAS.355..747J 2004MNRAS.355..747J,
2009MNRAS.399..683J 2009MNRAS.399..683J, Cat. VII/259).
File Summary:
--------------------------------------------------------------------------------
FileName Lrecl Records Explanations
--------------------------------------------------------------------------------
ReadMe 80 . This file
table1.dat 60 99 Main characteristics of the LLQSOs sample: HES
and 6dFGS names, J2000 coordinates and redshift
table4.dat 82 58 Fitting results of 6dFGS survey
table5.dat 76 72 Fitting results of HES survey
--------------------------------------------------------------------------------
See also:
VII/259 : 6dF galaxy survey final redshift release (Jones+, 2009)
J/A+AS/115/235 : The Hamburg/ESO survey for bright QSOs. II. (Reimers+, 1996)
J/A+A/561/A140 : Low-luminosity type-1 QSO sample (Busch+, 2014)
Byte-by-byte Description of file: table1.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 2 I2 --- Seq Sequential number
4- 14 A11 --- HES HES name (HENNNN-NNN)
16 A1 --- n_HES [123] Note on HES (1)
17 A1 --- f_Seq [+] + marks galaxies for which we do not have
HES optical spectra
19- 33 A15 --- 6dFGS 6dFGS name (gHHMMSSs+DDMMSS)
35- 43 F9.5 deg RAdeg Right ascension (J2000)
45- 53 F9.5 deg DEdeg Declination (J2000)
55- 60 F6.4 --- z Redshift
--------------------------------------------------------------------------------
Note (1): Notes as follows:
1 = Spectral resolution about 770km/s
2 = Spectral resolution about 880km/s
3 = Spectral resolution about 880km/s
--------------------------------------------------------------------------------
Byte-by-byte Description of file: table4.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 25 A25 --- Com Comments (G1)
26- 28 A3 --- Flag [d+ ] Flag (G2)
30- 31 I2 --- Seq Sequential number
33- 36 F4.2 --- [NII]/Ha ?=- [NII]/Hα luminosity ratio
38- 42 F5.2 --- [OIII]/Hb ?=- [OIII]/Hβ luminosity ratio
44- 47 F4.2 --- [SII]/Ha ?=- [SII]/Hα luminosity ratio
49- 52 F4.2 --- [OI]/Ha ?=- [OI]/Hα luminosity ratio
54- 58 F5.1 km/s FWHMHan ?=- Narrow component Hα FWHM
60- 66 F7.1 km/s FWHMHab ?=- Broad component Hα FWHM
67 A1 --- u_FWHMHab [?] Uncertainty flag on FWHMHab
68- 73 F6.1 --- FWHMHbn ?=- Narrow component Hβ FWHM
76- 82 F7.1 --- FWHMHbB ?=- Broad component Hβ FWHM
--------------------------------------------------------------------------------
Byte-by-byte Description of file: table5.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 18 A18 --- Com Comments (G1)
19- 20 A2 --- Flag [d+ ] Flag (G2)
22- 23 I2 --- Seq sequential number
25- 28 F4.2 --- [NII]/Ha ?=- [NII]/Hα luminosity ratio
30- 34 F5.2 --- [OIII]/Hb ?=- [OIII]/Hβ luminosity ratio
36- 39 I4 km/s FWHMHan ?=- Narrow component Hα FWHM
41- 45 I5 km/s FWHMHab ?=- Broad component Hα FWHM
47- 50 I4 km/s FWHMHbn ?=- Narrow component Hβ FWHM
52- 56 I5 km/s FWHMHbb ?=- Broad component Hβ FWHM
57- 76 A20 --- Note Notes
--------------------------------------------------------------------------------
Global notes:
Note (G1): comments describes broadly the quality of the spectra and the
emission of the lines.
Note (G2): Flag as follows:
d = source complains with the narrow line widths requirements defined
in Sect. 5.1
+ = source complains with the broad line widths requirements defined
in Sect. 5.1
--------------------------------------------------------------------------------
History:
From electronic version of the journal
References:
Busch et al., Paper I 2014A&A...561A.140B 2014A&A...561A.140B, Cat. J/A+A/561/A140
Busch et al., Paper II 2015A&A...575A.128B 2015A&A...575A.128B
(End) Patricia Vannier [CDS] 03-Nov-2015