J/A+A/615/A104 HRS gal. nuclear vs. integrated spectroscopy (Gavazzi+, 2018)
Nuclear versus integrated spectroscopy of galaxies in the
Herschel Reference Survey.
Gavazzi G., Consolandi G., Belladitta S., Boselli A., Fossati M.
<Astron. Astrophys. 615, A104 (2018)>
=2018A&A...615A.104G 2018A&A...615A.104G (SIMBAD/NED BibCode)
ADC_Keywords: Galaxy catalogs ; Galaxies, radio ; Spectroscopy
Keywords: galaxies: evolution - galaxies: fundamental parameters -
galaxies: star formation
Abstract:
The determination of the relative frequency of active galactic nuclei
(AGN) versus other spectral classes, for example, HII region-like
(HII), transition objects (TRAN), passive (PAS), and retired (RET), in
a complete set of galaxies in the local Universe is of primary
importance to discriminate the source of ionization in the nuclear
region of galaxies (e.g., supermassive black holes vs. young and old
stars).
Here we aim to provide a spectroscopic characterization of the nuclei
of galaxies belonging to the Herschel Reference Survey (HRS), a volume
and magnitude limited sample representative of the local Universe,
which has become a benchmark for local and high- z studies, for
semianalytical models and cosmological simulations. The comparison
between the nuclear spectral classification and the one determined on
the global galactic scale provides information about how galaxy
properties change from the nuclear to the outer regions. Moreover, the
extrapolation of the global star formation (SF) properties from the
SDSS fiber spectroscopy compared to the one computed by Hα
photometry can be useful for testing the method based on aperture
correction for determining the global star formation rate for local
galaxies.
By collecting the existing nuclear spectroscopy available from the
literature, complemented with new observations obtained using the
Loiano 1.52m telescope, we analyze the 322 nuclear spectra of HRS
galaxies; their integrated spectroscopy is available from the
literature as well.
Using two diagnostic diagrams (the BPT and the WHAN) we provide a
nuclear and an integrated spectral classification for the HRS
galaxies. The BPT and the WHAN methods for nuclei consistently give a
frequency of 53-64% HII, around 21-27% AGNs (including TRAN), and
15-20% of PAS (including RET), whereas for integrated spectra they
give 69-84% HII, 4-11% of AGNs and 12-20% PAS. Solely among
late-type galaxies (LTGs) do the nuclear percentages become 67-77%
HII, 22-27% AGNs (including TRAN), and only 1-7% of PAS. For the
integrated spectra these frequencies become: 80-85% HII, 9-11%
AGNs and 4-9% PAS.
We find that the fraction of HII region-like spectra is strongly
anticorrelated with the stellar mass. On the contrary the frequency of
AGNs increases significantly with stellar mass, such that at
M*>1010.0M☉∼66% of the LTGs are AGNs or TRAN. Moreover there
is not a significant dependence of the frequency of AGNs as a function
of environment: AGNs+TRAN above 109.0M☉ are consistent with
∼30% irrespective of their membership to the Virgo cluster, suggesting
that the AGNs population is not sensitive to the environment. Finally,
extrapolation of the global SF properties from the nuclear
spectroscopy including aperture corrections leads to underestimates
with respect to values derived from direct integrated Hα
photometry.
Description:
The sample of galaxies analyzed in this work is the (HRS; Boselli et
al., 2010, Cat. J/A+A/564/A65).
Most of HRS nuclear optical spectra were found in the literature.
In particular, 163 spectra were downloaded in FITS format from
the SDSS DR13 and DR12 database (Albareti et al.,
2017ApJS..233...25A 2017ApJS..233...25A); 114 spectra were found in the NASA/IPAC
Extragalactic Database (NED) and 104 of these are taken from Ho et al.
(1997, Cat. J/ApJS/112/315).
Nuclear spectroscopic observations of 45 HRS galaxies that were found
neither in the SDSS spectroscopic catalog nor within the NED database,
were obtained by us during several observing campaigns from 2000 to
2017 using the Bologna Faint Object Spectrograph and Camera (BFOSC)
mounted on the 152cm F/8 Cassini Telescope located in Loiano,
belonging to the Observatory of Bologna.
File Summary:
--------------------------------------------------------------------------------
FileName Lrecl Records Explanations
--------------------------------------------------------------------------------
ReadMe 80 . This file
tablea4.dat 106 322 Derived spectroscopic parameters of a sample
of 322 HRS galaxies
--------------------------------------------------------------------------------
See also:
VII/259 : 6dF galaxy survey final redshift release (Jones+, 2009)
J/ApJS/112/315 : Spectroscopic parameters of Seyfert nuclei (Ho+ 1997)
J/ApJS/126/331 : Spectrophotometry of nearby field galaxies (Jansen+ 2000)
J/PASP/122/261 : Herschel Reference Survey Sample, RDS (Boselli+, 2010)
J/A+A/543/A161 : Submillimetre obs. of 323 HRS nearby galaxies (Ciesla+, 2012)
J/A+A/564/A65 : HRS galaxies cold gas properties (Boselli+, 2014)
J/A+A/579/A102 : Hα imaging of Herschel Reference Survey (Boselli+, 2015)
Byte-by-byte Description of file: tablea4.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 3 I3 --- HRS HRS name ([BEC2010] HRS NNN in Simbad)
5 A1 --- Refint Reference to the integrated spectrum (1)
6- 8 A3 --- Noteint Note on integrated spectrum (2)
11- 16 F6.3 0.1nm EWHaint ?=- Equivalent width of Halpha in the
integrated spectrum corrected for
continuum absorption according to GANDALF,
positive EW means emission
17 A1 --- f_EWHaint [od] o for not observed, d for not detected
19- 24 F6.3 --- [OIII]/Hbint ?=- Line ratio [OIII]/Hbeta in the
integrated spectrum
25 A1 --- f_[OIII]/Hbint [od] o for not observed, d for not detected
27- 31 F5.2 --- [NII]/Haint ?=- Line ratio [NII]/Halpha in the
integrated spectrum
32 A1 --- f_[NII]/Haint [od] o for not observed, d for not detected
34- 37 F4.2 --- [SII]/Haint ?=- Line ratio [SII]/Halpha in the
integrated spectrum
38 A1 --- f_[SII]/Haint [od] o for not observed, d for not detected
40- 50 A11 --- BPTint BPT classification in the integrated
spectrum using the BPT ([NII]/Ha or
[SII]/Ha) diagrams (3)
51 A1 --- f_BPTint [od] o for not observed, d for not detected
53- 56 A4 --- WHANint WHAN classification in the integrated
spectrum using the WHAN diagram (3)
58- 60 A3 --- Refnuc Reference to the nuclear spectroscopy (4)
61- 67 F7.3 0.1nm EWHanuc ?=- EWHalpha in the nuclear spectrum
corrected for continuum absorption
according to GANDALF or according to
Table 1, positive EW means emission (5)
68 A1 --- f_EWHanuc [od] o for not observed, d for not detected
70- 74 F5.2 --- [OIII]/Hbnuc ?=- Line ratio [OIII]/Hbeta in the
nuclear spectrum
75 A1 --- f_[OIII]/Hbnuc [od] o for not observed, d for not detected
77- 81 F5.2 --- [NII]/Hanuc ?=- Line ratio [NII]/Halpha in the
nuclear spectrum
82 A1 --- f_[NII]/Hanuc [od] o for not observed, d for not detected
84- 87 F4.2 --- [SII]/Hanuc ?=- Line ratio [SII]/Halpha in the
nuclear spectrum
88 A1 --- f_[SII]/Hanuc [od] o for not observed, d for not detected
90-100 A11 --- BPTnuc Classification in the nuclear spectrum
using the BPT ([NII]/Ha or [SII]/Ha)
diagrams (3)
101 A1 --- f_BPTnuc [od] o for not observed, d for not detected
103-106 A4 --- WHANnuc Classification in the nuclear spectrum
using the WHAN diagram (3)
--------------------------------------------------------------------------------
Note (1): Reference to the integrated spectrum as follows:
1 = B15; Boselli et al., 2015, Cat. J/A+A/579/A102
2 = Kennicutt et al. (1992ApJ...388..310K 1992ApJ...388..310K).
o = not observed
Note (2): Code as follows:
a = galaxies with integrated spectra remeasured by us using the GANDALF code
b = galaxies with Hbeta SN<3.0;
c = galaxies with Halpha SN<3.0 in the integrated spectrum
Note (3): two BPT classifications are reported:
the first spectral type is from the BPT with [NII]/Hα ratio,
the second is from the BPT with [SII]/Hα ratio.
Classification as follows:
AGN = active galactic nuclei
sAGN = strong AGNs
wAGN = weak AGNs
LIN = low-ionization nuclear emission-line region, LINER
SEY = Seyfert
HII = HII region-like
TR = transition objects
(PAS) = passive, galaxies whose spectra do not contain Hα, [NII],
[OIII], Hβ, [SII](6716Å) and [SII](6731Å) in emission.
Note (4): References as follows:
3 = this work or Gavazzi et al. (2013A&A...558A..31L 2013A&A...558A..31L)
4 = SDSS DR13 or DR12 (Albareti et al., 2017ApJS..233...25A 2017ApJS..233...25A)
5 = Ho et al. (1997, Cat. J/ApJS/112/315)
6 = Jones et al. (2009MNRAS.399..683J 2009MNRAS.399..683J, Cat. VII/259)
7 = Veilleux et al. (1995ApJS...98..171V 1995ApJS...98..171V)
8 = Jansen et al. (2000, Cat. J/ApJS/126/331)
9 = Falco et al. (1999, Cat. J/PASP/111/438)
d = galaxies with nuclear Hbeta SN<3.0
Note (5): Table 1: Continuum correction to Hα EW as derived
from the color-mass relation of Fig. 2.
-----------------------------------------------------------------
8≤M*<9 9≤M*≤10 10<M*≤11
-----------------------------------------------------------------
0.8<g-i≤1.2 1.94±0.41 1.91±0.29 1.81±0.24
0.4≤g-i≤0.8 2.43±0.63 2.25±0.45 1.98±0.32
g-i<0.4 2.57±0.63 2.48±0.51 ---
-----------------------------------------------------------------
--------------------------------------------------------------------------------
Acknowledgements:
Giuseppe Gavazzi, peppogavazzi(at)gmail.com
(End) Patricia Vannier [CDS] 11-Aug-2018