J/MNRAS/477/4116 GAMA. galaxy structure across green valley (Kelvin+, 2018)
Galaxy and Mass Assembly (GAMA):
Variation in galaxy structure across the green valley.
Kelvin L.S., Bremer M.N., Phillipps S., James P.A., Davies L.J.M.,
De Propris R., Moffett A.J., Percival S.M.
<Mon. Not. R. Astron. Soc. 477, 4116-4130 (2018)>
=2018MNRAS.477.4116K 2018MNRAS.477.4116K (SIMBAD/NED BibCode)
ADC_Keywords: Surveys ; Galaxy catalogs ; Morphology
Keywords: galaxies: elliptical and lenticular, cD - galaxies: evolution -
galaxies: spiral - galaxies: star formation - galaxies: statistics -
galaxies: structure
Abstract:
Using a sample of 472 local Universe (z<0.06) galaxies in the stellar
mass range 10.25<logM*/M☉<10.75, we explore the variation in
galaxy structure as a function of morphology and galaxy colour. Our
sample of galaxies is sub-divided into red, green and blue colour
groups and into elliptical and non-elliptical (disk-type)
morphologies. Using KiDS and VIKING derived postage stamp images, a
group of eight volunteers visually classified bars, rings,
morphological lenses, tidal streams, shells and signs of merger
activity for all systems. We find a significant surplus of rings
(2.3σ) and lenses (2.9σ) in disk-type galaxies as they
transition across the green valley. Combined, this implies a joint
ring/lens green valley surplus significance of 3.3σ relative to
equivalent disk-types within either the blue cloud or the red
sequence. We recover a bar fraction of ∼44% which remains flat with
colour, however, we find that the presence of a bar acts to modulate
the incidence of rings and (to a lesser extent) lenses, with rings in
barred disk-type galaxies more common by ∼20-30 percentage points
relative to their unbarred counterparts, regardless of colour.
Additionally, green valley disk-type galaxies with a bar exhibit a
significant 3.0σ surplus of lenses relative to their blue/red
analogues. The existence of such structures rules out violent
transformative events as the primary end-of-life evolutionary
mechanism, with a more passive scenario the favoured candidate for the
majority of galaxies rapidly transitioning across the green valley.
Description:
This table contains the output of the Green Valley Census, a programme
designed to visually classify structural features in a set of galaxies
in, and either side of, the green valley. Visual classification was
conducted using the Zooniverse web platform. A group of eight
classifiers examined monochromatic and 3-colour optical/NIR imaging
for 472 galaxies of varying morphological type and colour to visually
determine the presence of bars, rings, morphological lenses, tidal
features, shells and signs of a merger or interaction. This table
contains these results as binary flags, in addition to ancillary
information for each galaxy. See paper for further details.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
gvcensus.dat 67 3776 Green Valley Census
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See also:
J/MNRAS/413/971 : Galaxy And Mass Assembly (GAMA) DR1 (Driver+, 2011)
J/MNRAS/449/4277 : GAMA blended spectra catalogue (Holwerda+, 2015)
Byte-by-byte Description of file: gvcensus.dat
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Bytes Format Units Label Explanations
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1- 7 I7 --- GAMA GAMA Catalogue ID
9- 16 F8.4 deg RAdeg Right ascension (J2000)
18- 28 F11.8 deg DEdeg Declination (J2000)
30- 38 A9 --- HType Hubble type (1)
40- 41 I2 --- HCode Hubble type code (2)
43- 47 A5 --- Colour Colour (3)
49 I1 --- CCode Colour code (4)
51 I1 --- UseriD Anonymised user ID
53 I1 --- Wbar [0/1] Weakly barred
55 I1 --- Sbar [0/1] Strongly barred
57 I1 --- Bar [0/1] Bar (combined weak/strong bar)
59 I1 --- Ring [0/1] Ring / partial ring
61 I1 --- Lens [0/1] Plateau / lens
63 I1 --- Tidal [0/1] Tidal tails / streams
65 I1 --- Shell [0/1] A shell / shells
67 I1 --- Merger [0/1] Interaction / merger
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Note (1): Grouped Hubble type morphologies
Note (2): Classification schema established in Kelvin et al.,
2014MNRAS.439.1245K 2014MNRAS.439.1245K. See paper for further details.
Classification code as follows:
1 = E (elliptical)
11 = S0-Sa (lenticular / early-type spiral)
12 = SB0-SBa (barred lenticular / early-type spiral)
13 = Sab-Scd (intermediate-type spiral)
14 = SBab-SBcd (barred intermediate-type spiral)
15 = Sd-Irr (late-type spiral / irregular)
Note (3): Grouped colour IDs, based on dust-corrected u-r colours
(red, green or blue). See paper for further details.
Note (4): Colour code as follows:
1 = red
2 = green
3 = blue
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Acknowledgements:
Lee Kelvin, l.s.kelvin(at)ljmu.ac.uk
(End) Patricia Vannier [CDS] 26-Mar-2018