J/MNRAS/478/4293 0.1<z<0.8 galaxies gas-phase metallicity grad. (Carton+, 2018)
First gas-phase metallicity gradients of 0.1<z<0.8 galaxies with MUSE.
Carton D., Brinchmann J., Contini T., Epinat B., Finley H., Richard J.,
Patricio V., Schaye J., Nanayakkara T., Weilbacher P.M., Wisotzki
<Mon. Not. R. Astron. Soc. 478, 4293 (2018)>
=2018MNRAS.478.4293C 2018MNRAS.478.4293C (SIMBAD/NED BibCode)
ADC_Keywords: Galaxy catalogs ; Abundances ; Redshifts ; Interstellar medium
Keywords: galaxies: evolution - galaxies: abundances - galaxies: ISM
Abstract:
Galaxies at low-redshift typically possess negative gas-phase
metallicity gradients (centres more metal-rich than their outskirts).
Whereas, it is not uncommon to observe positive metallicity gradients
in higher-redshift galaxies (z<0.6). Bridging these epochs, we
present gas-phase metallicity gradients of 84 star-forming galaxies
between 0.08<z<0.84. Using the galaxies with reliably determined
metallicity gradients, we measure the median metallicity gradient to
be negative (-0.039+0.007-0.009dex/kpc). Underlying this,
however, is significant scatter: (8±3)% [7] of galaxies have
significantly positive metallicity gradients, (38±5)% [32] have
significantly negative gradients, (31±5)% [26] have gradients
consistent with being flat. (The remaining (23±5)% [19] have
unreliable gradient estimates.) We notice a slight trend for a more
negative metallicity gradient with both increasing stellar mass and
increasing star formation rate (SFR). However, given the potential
redshift and size selection effects, we do not consider these trends
to be significant. Indeed, once we normalize the SFR relative to that
of the main sequence, we do not observe any trend between the
metallicity gradient and the normalized SFR. This is contrary to
recent studies of galaxies at similar and higher redshifts. We do,
however, identify a novel trend between the metallicity gradient of a
galaxy and its size. Small galaxies (rd<3kpc) present a large
spread in observed metallicity gradients (both negative and positive
gradients). In contrast, we find no large galaxies (rd > 3 kpc) with
positive metallicity gradients, and overall there is less scatter in
the metallicity gradient amongst the large galaxies. These large
(well-evolved) galaxies may be analogues of present-day galaxies,
which also show a common negative metallicity gradient.
Description:
Using MUSE data we present metallicity gradients for a sample of 84
intermediate-redshift galaxies (0.1≲z≲0.8). We infer the true
metallicity gradient using a forward-modelling technique that corrects
for the seeing effects. We search for trends of the observed
metallicity gradient with global properties such as galaxy mass, size,
and SFR.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . this file
tablea1.dat 169 84 Metallicity, mass, SFR and morphological
properties
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Byte-by-byte Description of file: tablea1.dat
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Bytes Format Units Label Explanations
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1- 5 A5 --- Field Targeted field (1)
7- 14 I8 --- ID ID number of galaxy within field (1)
16- 21 F6.3 [-] logZ0 [-0.714/0.696] Derived central
metallicity (2)
23- 28 F6.3 [-] b_logZ0 [-0.854/-0.004] -1 sigma error on logZ0 (3)
30- 34 F5.3 [-] B_logZ0 [0.002/0.5] ? +1 sigma error on logZ0 (4)
36- 42 F7.4 kpc-1 dlogZ [-0.2615/0.2406] Derived metallicity
gradient (2)
44- 50 F7.4 kpc-1 b_dlogZ [-0.3773/-0.0009] -1 sigma error
on dlogZ (3)
52- 57 F6.4 kpc-1 B_dlogZ [0.0009/0.2314] +1 sigma error on dlogZ (4)
59- 68 A10 --- Grad Metallicity gradient classification
70- 75 F6.3 [Msun] Mass [7.002/10.6] ? Stellar mass derived from
MAGPHYS (2)
77- 82 F6.3 [Msun] b_Mass [-0.315/0.0] -1 sigma error on Mass (3)
84- 88 F5.3 [Msun] B_Mass [0.0/0.365] +1 sigma error on Mass (4)
90- 95 F6.3 [Msun/yr] SFR [-2.254/1.42] SFR derived from
emission lines (2)
97-102 F6.3 [Msun/yr] b_SFR [-0.573/-0.006] -1 sigma error on SFR (3)
104-108 F5.3 [Msun/yr] B_SFR [0.008/0.673] +1 sigma error on SFR (4)
110-115 F6.3 --- dSFR [-0.8/1.167] Galaxy SFR normalized relative
to a galaxy with identical mass on the main
sequence
117-121 F5.3 --- e_dSFR [0.017/0.61] 1 sigma error on dSFR
123-132 F10.6 deg RAdeg [53/338.3] Right ascension of galaxy
centre (J2000)
134-143 F10.6 deg DEdeg [-60.58/2.08] Declination of galaxy
centre (J2000)
145-150 F6.4 --- z [0.0771/0.8441] Redshift derived from MUSE
spectra
152-155 F4.2 kpc rd [0.15/6.71] Exponential disc scale length
157-161 F5.2 deg Inc [0.58/70.0] Galaxy inclination
163-169 F7.2 deg PA [-88.32/144.0] Position angle of galaxy's
major axis on the sky, North=0, East=90
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Note (1): Field and ID can be combined to produce a unique key
Note (2): Median value
Note (3): -1 sigma is defined by the 16th percentile
Note (4): +1 sigma is defined by the 84th percentile
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Acknowledgements:
David Carton, david.carton(at)univ-lyon1.fr
(End) Patricia Vannier [CDS] 17-May-2018