J/A+A/611/A28 ATLAS3D Hα imaging of early-type galaxies (Gavazzi+, 2018)
Hα imaging observations of early-type galaxies from the ATLAS3D survey.
Gavazzi G., Consolandi G., Pedraglio S., Fossati M., Fumagalli M.,
Boselli A.
<Astron. Astrophys. 611, A28 (2018)>
=2018A&A...611A..28G 2018A&A...611A..28G (SIMBAD/NED BibCode)
ADC_Keywords: Galaxies, nearby ; Redshifts ; Photometry, H-alpha
Keywords: Galaxy: evolution - galaxies: elliptical and lenticular, cD -
galaxies: fundamental parameters - galaxies: star formation
Abstract:
The traditional knowledge of the mechanisms that caused the formation
and evolution of early-type galaxies (ETG) in a hierarchical universe
was challenged by the unexpected finding by ATLAS3D that 86% of the
ETGs show signs of a fast-rotating disk at their interior. This
implies a common origin of most spiral galaxies, followed by a
quenching phase, while only a minority of the most massive systems are
slow rotators and were likely to be the products of merger events.
Our aim is to improve our knowledge on the content and distribution of
ionized hydrogen and their usage to form stars in a representative
sample of ETGs for which the kinematics and detailed morphological
classification were known from ATLAS3D. Methods. Using narrow-band
filters centered on the redshifted Hα line along with a
broad-band (r-Gunn) filter to recover the stellar continuum, we
observed or collected existing imaging observations for 147 ETGs
(including members of the Virgo cluster) that are representative of
the whole ATLAS3D survey.
Fifty-five ETGs (37%) were detected in the Hα line above our
detection threshold, (EW(Hα)≤-1Å), and 21 harbor a strong
source (EW(Hα)≤-5Å).
The strong Hα emitters appear associated with mostly low-mass
(M*∼1010M☉) S0 galaxies that contain conspicuous stellar and
gaseous discs. These harbor significant star formation at their
interior, including their nuclei. The weak Hα emitters are
almost one order of magnitude more massive, contain gas-poor discs and
harbor an AGN at their centers. Their emissivity is dominated by [NII]
and does not imply star formation. The 92 undetected ETGs constitute
the majority in our sample and are gas-free systems that lack a disc
and exhibit passive spectra even in their nuclei. These pieces of
evidence reinforce the conclusion made previously that the evolution
of ETGs followed the secular channel for the less massive systems and
the dry merging channel for the most massive galaxies at the center of
clusters of galaxies.
Description:
The sample of ETGs analyzed in this work was extracted from
the ATLAS3D whole-sky catalog of 260 ETGs.
Narrow-band imaging of the Hα line emission (rest frame
λ=6562.8Å) of 118 galaxies in the main program (+ 20 filler
targets) was obtained using the 2.1m telescope at the SPM, belonging
to the Mexican Observatorio Astronomico Nacional (OAN). The Hα
measurements of the remaining 29 targets included in the present
investigation are taken from the literature. The observations were
scheduled in two observing runs of eight nights each in 2015 (March
17-24) and 2016 (April 7-14), both including new-moon periods.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
tablea1.dat 91 147 General parameters of the 147 target galaxies
tablea2.dat 68 20 General parameters of the 20 filler targets
tablea3.dat 49 147 The observational parameters of the 147
observed galaxies
tablea4.dat 49 20 The observational parameters of the 20
filter targets
tablea5.dat 91 147 The results of our Halpha imaging campaign for
the 147 target galaxies
tablea6.dat 70 20 The results of our Halpha imaging campaign for
the 20 filler targets
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See also:
J/MNRAS/413/813 : ATLAS3D project. I. (Cappellari+, 2011)
J/MNRAS/414/888 : ATLAS3D project. III. (Emsellem+, 2011)
J/MNRAS/414/940 : ATLAS3D project. IV. (Young+, 2011)
J/MNRAS/416/1680 : ATLAS3D project. VII. (Cappellari+, 2011)
J/MNRAS/433/2812 : ATLAS3D project. XXIII. (Krajnovic+, 2013)
J/MNRAS/448/3484 : ATLAS3D Project. XXX (McDermid+, 2015)
Byte-by-byte Description of file: tablea1.dat tablea2.dat
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Bytes Format Units Label Explanations
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1- 10 A10 --- Galaxy Galaxy name
12- 13 I2 h RAh Right ascension (J2000)
15- 16 I2 min RAm Right ascension (J2000)
18- 22 F5.2 s RAs Right ascension (J2000)
24 A1 --- DE- Declination sign (J2000)
25- 26 I2 deg DEd Declination (J2000)
28- 29 I2 arcmin DEm Declination (J2000)
31- 34 F4.1 arcsec DEs Declination (J2000)
36- 39 I4 km/s cz ? Recessional velocity
41- 45 F5.1 Mpc D ? Distance in Mpc
47- 50 A4 --- Type Morphological type
52- 56 F5.2 mag gmag ?=- g magnitude from Consolandi et al.
(2016, Cat. J/A+A/591/A38)
58- 62 F5.2 mag rmag ?=- r magnitude from Consolandi et al.
(2016, Cat. J/A+A/591/A38)
64- 69 F6.3 [Msun] logMstar ?=- log of stellar mass
71- 73 A3 --- Rot Kinematic classification in ATLAS3D
75 A1 --- l_logMH2Y [=<] Limit flag on MH2Y
("=" detected, < upper limit)
77- 80 F4.2 [Msun] logMH2Y ?=- log of the molecular hydrogen mass (H2)
as given by Young et al.
(2011, Cat. J/MNRAS/414/940)
81- 82 A2 --- n_logMH2Y [H2 ] Note on MH2Y (1)
84 A1 --- l_logMH2S [=<] Limit flag on MH2S
("=" detected, < upper limit)
86- 89 F4.2 [Msun] logMH2S ?=- log of the atomic hydrogen mass (H2)
as given by Serra et al.
(2012MNRAS.422.1835S 2012MNRAS.422.1835S)
90- 91 A2 --- n_logMH2S [HI ] Note on MH2S (2)
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Note (1): when a CO spectrum is available from the NED, but an estimate of the
H2 mass is not given, a "H2" is reported.
Note (2): when a HI spectrum is available from NED (mostly from ALFALFA), but
an estimate of the HI mass is not given, a "HI" is reported.
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Byte-by-byte Description of file: tablea3.dat tablea4.dat
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Bytes Format Units Label Explanations
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1- 11 A11 --- Galaxy Galaxy name
13- 14 I2 --- Ref [1/11] Reference to the Halpha observation (G1)
16- 19 F4.2 --- AmON15 ? Air mass during the ON-band exposure in 2015
21- 24 F4.2 --- AmOFF15 ? Air mass during the OFF-band exposure in 2015
26- 29 F4.2 --- AmON16 ? Air mass during the ON-band exposure in 2016
31- 34 F4.2 --- AmOFF16 ? Air mass during the OFF-band exposure in 2016
36- 38 I3 s TexpON25 ? Exposure time of the individual ON-band
exposure in 2015
40- 41 I2 s TexpOFF15 ? Exposure time of the individual OFF-band
exposure in 2015
43- 45 I3 s TexpON26 ? Exposure time of the individual ON-band
exposure in 2016
47- 49 I3 s TexpOFF16 ? Exposure time of the individual OFF-band
exposure in 2016
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Byte-by-byte Description o file: tablea5.dat tablea6.dat
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Bytes Format Units Label Explanations
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1- 11 A11 --- Galaxy Galaxy name
13- 19 F7.2 0.1nm EW3as ? Halpha+[NII] (negative means emission)
measured in a circular aperture of 3"
positioned on the galaxy nucleus
21- 24 F4.2 0.1nm e_EW3as ? rms uncertainty of the (EW) Halpha+[NII]
measured in a circular aperture of 3"
26 A1 --- l_LogF3as Limit flag on LogF3as (< for undetection)
27- 32 F6.2 [mW/m2] LogF3as ? log of the Halpha+[NII] flux measured in a
circular aperture of 3" positioned on the
galaxy nucleus;
34- 37 F4.2 [mW/m2] e_LogF3as ? rms uncertainty of LogF3as
39- 45 F7.2 0.1nm EWtot ? Total (EW) Halpha+[NII] measured in a
circular aperture containing the whole galaxy
47- 50 F4.2 0.1nm e_EWtot ? rms uncertainty on EWtot
52 A1 --- l_LogFTot Limit flag on LogFTot (< for undetection)
53- 58 F6.2 [mW/m2] LogFTot ? log of the Halpha+[NII] flux measured in a
circular aperture containing the whole galaxy
60- 63 F4.2 [mW/m2] e_LogFTot ? rms uncertainty on LogFTot
65 A1 --- l_logSFR Limit flag on logSFR (< for undetection)
66- 70 F5.2 [Msun/yr] logSFR ? log of the total star formation rate derived
from the Halpha flux (1)
72- 76 A5 --- Spec Availability of a nuclear spectrum flag (2)
78- 80 A3 --- SpecTy Nuclear spectral classification (3)
82 I1 --- Det [1/3]? Detection flag (4)
84 A1 --- morfHa Halpha morphological classification (5)
86 A1 --- HST HST imaging availability flag (6)
88- 91 A4 --- Ref Reference to Halpha imaging (G1)
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Note (1): as prescribed by Kennicutt (1998ARA&A..36..189K 1998ARA&A..36..189K), but adapted for
a Chabrier IMF.
Note (2): Availability of a nuclear spectrum flag as follows:
LOI = taken at the Loiano 1.5m telescope (this work)
SDSS = taken from the SDSS database
NED = taken from NED
HO = in Ho et al. (1995, Cat. J/ApJS/98/477)
NEDMH = from NED taken at Mount Hopkins 1.5m telescope
Note (3): HII, SEY, AGN, PSB, RET, PAS, according to the criteria of
Gavazzi et al. (2012, Cat. J/A+A/545/A16; 2013, Cat. J/A+A/558/A68)
Note (4): Detection flag as follows:
1 = strong Halpha detection
2 = weak detection
3 = undetected
Note (5): Halpha morphological classification as follows:
d = disc
D = diffuse
c = centrally peaked
F = filamentary
Note (6): HST imaging availability flag as follows:
- = not available
0 = available, featureless
1 = available, showing a prominent structure (disc, dust ring, or filaments)
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Global notes:
Note (G1): References as follows:
1 = this work
2 = Koopmann and Kenney (2006ApJS..162...97K 2006ApJS..162...97K)
3 = Boselli at al. (2015, Cat. J/A+A/579/A102)
4 = Young et al. (1996AJ....112.1903Y 1996AJ....112.1903Y)
5 = Macchetto et al. (1996A&AS..120..463M 1996A&AS..120..463M)
6 = Koopmann et al. (2001ApJS..135..125K 2001ApJS..135..125K)
7 = Boselli and Gavazzi (2002A&A...386..124B 2002A&A...386..124B)
8 = Kennicutt and Kent (1983AJ.....88.1094K 1983AJ.....88.1094K)
9 = Trinchieri and Di Serego Alighieri (1991AJ....101.1647T 1991AJ....101.1647T)
10 = Gavazzi et al. (2000A&A...361....1G 2000A&A...361....1G)
11 = Kenney et al. (2008ApJ...687L..69K 2008ApJ...687L..69K)
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Acknowledgements:
Giuseppe Gavazzi, giuseppe.gavazzi(at)mib.infn.it
(End) Patricia Vannier [CDS] 28-Sep-2017