J/MNRAS/456/1299 SAMI Galaxy Survey: gas streaming (Cecil+, 2016)
The SAMI Galaxy Survey: gas streaming and dynamical M/L in rotationally
supported systems.
Cecil G., Fogarty L.M.R., Richards S., Bland-Hawthorn J., Lange R.,
Moffett A., Catinella B., Cortese L., Ho I.-T., Taylor E.N., Bryant J.J.,
Allen J.T., Sweet S.M., Croom S.M., Driver S.P., Goodwin M., Kelvin L.,
Green A.W., Konstantopoulos I.S., Owers M.S., Lawrence J.S., Lorente N.P.F.
<Mon. Not. R. Astron. Soc., 456, 1299-1319 (2016)>
=2016MNRAS.456.1299C 2016MNRAS.456.1299C (SIMBAD/NED BibCode)
ADC_Keywords: Galaxy catalogs ; Morphology
Keywords: galaxies: kinematics and dynamics - galaxies: spiral -
galaxies: structure
Abstract:
Line-of-sight velocities of gas and stars can constrain dark matter
(DM) within rotationally supported galaxies if they trace circular
orbits extensively. Photometric asymmetries may signify non-circular
motions, requiring spectra with dense spatial coverage. Our
integral-field spectroscopy of 178 galaxies spanned the mass range of
the Sydney-AAO Multi-object integral field spectrograph (SAMI) Galaxy
Survey. We derived circular speed curves (CSCs) of gas and stars from
non-parametric fits out to r∼2re. For 12/14 with measured HI profiles,
ionized gas and HI maximum velocities agreed. We fitted
mass-follows-light models to 163 galaxies by approximating the radial
light profile as nested, very flattened mass homeoids viewed as a
Sersic form. Fitting broad-band spectral energy distributions to Sloan
Digital Sky Survey images gave median stellar mass/light 1.7 assuming
a Kroupa initial mass function (IMF) versus 2.6 dynamically.
Two-thirds of the dynamical mass/light measures were consistent with
star+remnant IMFs. One-fifth required upscaled starlight to fit, hence
comparable mass of unobserved baryons and/or DM distributed like
starlight across the SAMI aperture that came to dominate motions as
the starlight CSCs declined rapidly. The rest had mass distributed
differently from light. Subtracting fits of Sersic radial profiles to
13 VIKING Z-band images revealed residual weak bars. Near the bar
major axis, we assessed m=2 streaming velocities, and found deviations
usually <30km/s from the CSC; three showed no deviation. Thus,
asymmetries rarely influenced the CSC despite colocated
shock-indicating, emission-line flux ratios in more than 2/3 of our
sample.
Description:
From the first ∼830 targets observed in the SGS, we selected 344
rotationally supported galaxies having enough gas to map their CSC. We
rejected 8 whose inclination angle to us is too small (i<20°) to
be established reliably by photometry, and those very strongly barred
or in obvious interactions. Finally, we rejected those whose CSC would
be smeared excessively by our PSF (Sect. 2.3.1) because of large
inclination (i>71°), compact size, or observed in atrocious
conditions, leaving 163 SGS GAMA survey sub-sample and 15 "cluster"
sub-sample galaxies with discs.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 78 163 Diskfit results for most of the SGS GAMA-Survey
sub-sample
table2.dat 64 15 Diskfit results for the SGS cluster subsample
table3.dat 61 13 Diskfit results for some plausible weak bars
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See also:
J/MNRAS/446/1567 : SAMI Galaxy Survey: EDR (Allen+, 2015)
J/MNRAS/454/2050 : SAMI Pilot Survey (Fogarty+, 2015)
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 6 I6 --- GAMA GAMA identification number
8- 15 F8.6 --- z Fitted redshift
17- 18 I2 % FLine Per cent of r-band flux from line emission
19- 22 A4 --- n_FLine Note on FLine (1)
24- 27 F4.1 --- DISM ISM dispersion to normalize diskfit
reduced chi2
29- 32 F4.1 deg Incl Inclination is fixed at GAMA Survey
sigma prior
34- 38 F5.1 deg PA Diskfit evaluated PA is east from N
40- 43 F4.1 deg e_PA Bootstrapped error on PA
45- 48 F4.2 --- chi2 Reduced chi2 of fit
50- 52 I3 --- DOF degrees of freedom
54- 56 I3 km/s Vmax Maximum velocity
58 I1 --- n_Vmax [1/3] 1 = sharpest quartile, 2 = to median,
etc.
60- 62 F3.1 --- rmax Radius of maximum velocity within the SAMI
aperture in re unit
64- 66 F3.1 --- gammax Dynamical variable mass-to-light ratio, gammax
67 A1 --- n_gammax [f] Note on gammax (1)
70- 72 F3.1 --- gammaP Broad-band colour fitted variable
mass-to-light ratio, gammaP, corrected for
line emission and dust
74- 78 F5.1 10+9Msun Mass Dynamical mass from gammax * Lr
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Note (1): Notes as follows:
a = has HI velocity profile measurement (Fig. 8)
b = extended shock w/ asymmetric starlight
c = extended shock, symmetric starlight
d = compact shock at centre
e = no shock but asymmetric starlight; otherwise no shock, symmetric starlight
f = MXL fit failed because mass does not follow light. Changing the intrinsic
flattening from q=0.1 to q=0.05 or 0.25 would multiply the listed
gammax by 0.76 or 1.3, respectively.
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Byte-by-byte Description of file: table2.dat
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Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 18 A18 --- GAMA GAMA ID (HHMMSS+ss+DDMMSS.s)
20- 27 F8.6 --- z Fitted redshift
29- 31 F3.1 --- DISM ISM dispersion to normalize diskfit reduced chi2
33- 36 F4.1 deg Inc Inclination
38- 41 F4.1 deg e_Inc rms uncertainty on Inc
43- 47 F5.1 deg PA [] Diskfit evaluated PA is east from N
49- 51 F3.1 deg e_PA Bootstrapped error on PA
53- 56 F4.2 --- chi2 Fit chi2
58- 60 I3 --- DOF Degree of freedom
62- 64 I3 km/s Vmax Maximum velocity
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Byte-by-byte Description of file: table3.dat
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Bytes Format Units Label Explanations
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1- 6 I6 --- GAMA GAMA identification number
8- 14 F7.5 --- z Fitted redshift
16- 17 I2 --- DISM ISM dispersion to normalize diskfit reduced chi2
19- 22 F4.1 deg Inc Inclination
24- 29 F6.1 deg PAD [] Disk PA is east from N
31- 33 F3.1 deg e_PAD rms uncertainty on PAD
35- 37 F3.1 --- chi2 Fit chi2
39- 41 I3 --- DOF Degree of freedom
43- 46 I4 deg PAB [] Bar PA is east from N
48- 50 I3 km/s Vtmax CSC maximum velocity in SAMI aperture at
the r/re shown
52 A1 --- leVtmax Limit flag on e_Vtmax
53- 55 F3.1 km/s e_Vtmax rms uncertainty on Vtmax
57- 58 I2 km/s Vt2max Tangential m = 2 motion
60- 61 I2 km/s Vr2max Radial m = 2 motion
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History:
From electronic version of the journal
(End) Patricia Vannier [CDS] 05-Aug-2016