J/MNRAS/492/821 The KLEVER Survey: metallicity maps and gradients (Curti+, 2020)
The KLEVER Survey: spatially resolved metallicity maps and gradients in a
sample of 1.2<z<2.5 lensed galaxies.
Curti M., Maiolino R., Cirasuolo M., Mannucci F., Williams R.J., Auger M.,
Mercurio A., Hayden-Pawson C., Cresci G., Marconi A., Belfiore F.,
Cappellari M., Cicone C., Cullen F., Meneghetti M., Ota K., Peng Y.,
Pettini M., Swinbank M., Troncoso P.
<Mon. Not. R. Astron. Soc., 492, 821-842 (2020)>
=2020MNRAS.492..821C 2020MNRAS.492..821C (SIMBAD/NED BibCode)
ADC_Keywords: Galaxies, spectra ; Gravitational lensing ; Abundances ;
Redshifts ; Spectra, infrared
Keywords: galaxies: abundances - galaxies: evolution - galaxies: high-redshift
Abstract:
We present near-infrared observations of 42 gravitationally lensed
galaxies obtained in the framework of the KMOS Lensed Emission Lines
and VElocity Review (KLEVER) Survey, a programme aimed at
investigating the spatially resolved properties of the ionized gas in
1.2<z<2.5 galaxies by means of a full coverage of the YJ, H, and K
near-infrared bands. Detailed metallicity maps and gradients are
derived for a subsample of 28 galaxies from reconstructed source-plane
emission-line maps, exploiting the variety of different emission-line
diagnostics provided by the broad wavelength coverage of the survey.
About 85 per cent of these galaxies are characterized by metallicity
gradients shallower than 0.05dex/kpc and 89 per cent are consistent
with a flat slope within 3σ (67 per cent within 1σ),
suggesting a mild evolution with cosmic time. In the context of
cosmological simulations and chemical evolution models, the presence
of efficient feedback mechanisms and/or extended star formation
profiles on top of the classical 'inside-out' scenario of mass
assembly is generally required to reproduce the observed flatness of
the metallicity gradients beyond z∼1. Three galaxies with
significantly (>3σ) 'inverted' gradients are also found, showing
an anticorrelation between metallicity and star formation rate density
on local scales, possibly suggesting recent episodes of pristine gas
accretion or strong radial flows in place. Nevertheless, the
individual metallicity maps are characterized by a variety of
different morphologies, with flat radial gradients sometimes hiding
non-axisymmetric variations on kpc scales, which are washed out by
azimuthal averages, especially in interacting systems or in those
undergoing local episodes of recent star formation.
Description:
KLEVER is an ESO Large Program (197.A-0717, PI: Michele Cirasuolo)
conducted with the multi-object near-IR integral field spectrograph
KMOS on the VLT (Sharples et al. 2013Msngr.151...21S 2013Msngr.151...21S). The survey is
designed to provide a full coverage of the near-infrared region of the
spectrum by observing each galaxy in the YJ, H, and K bands. The
analysis presented in this paper is based on the first available
observations in KLEVER, targeting 39 gravitationally lensed galaxies
behind the clusters MS2137-2353 (hereafter, MS2137) and RXJ2248.7-4431
(also known as AS1063, hereafter RXJ2248) and carried out in Service
Mode during Periods 95-97 (from 2015 May to 2016 September).
In addition, we have included in the analysis three strongly lensed
galaxies at z>2 observed with the integral field spectrograph SINFONI.
Two out of the three galaxies were observed as part of some of our
previous programs: SDSS J114833+193003 (also known as the Horseshoe)
and a strongly lensed, arc-like shaped galaxy within the MACS
J0451+0006 (MACS0451) cluster. The observations of the third
additional galaxy (SDSS J0232-0323, also known as CSWA164 as part of
the CASSOWARY Survey; Belokurov et al. 2009MNRAS.392..104B 2009MNRAS.392..104B) were
retrieved instead from the ESO archive. This brings the total observed
sample to 42 galaxies.
File Summary:
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FileName Lrecl Records Explanations
--------------------------------------------------------------------------------
ReadMe 80 . This file
table2.dat 130 43 The full sample of galaxies analysed in this
work
table3.dat 111 44 Global properties of the analysed sample
table4.dat 79 28 Radial gradients for galaxies for which they
could be at least marginally resolved
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Byte-by-byte Description of file: table2.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 7 A7 --- Inst Spectrograph used for the observations
(SINFONI or KMOS)
9- 24 A16 --- Cluster Galaxy cluster
26- 54 A29 --- Name Galaxy name
56 A1 --- f_Name [*] Flag on Name (1)
58- 59 I2 h RAh Right ascension (J2000)
61- 62 I2 min RAm Right ascension (J2000)
64- 69 F6.3 s RAs Right ascension (J2000)
71 A1 --- DE- Declination sign (J2000)
72- 73 I2 deg DEd Declination (J2000)
75- 76 I2 arcmin DEm Declination (J2000)
78- 83 F6.3 arcsec DEs Declination (J2000)
85- 90 F6.4 --- z Spectroscopic redshift (2)
92-100 A9 --- ELJ Main emission lines detected above 3σ
in the J-band
102-115 A14 --- ELH Main emission lines detected above 3σ
in the H-band
117-130 A14 --- ELK Main emission lines detected above 3σ
in the K-band
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Note (1): Flag as follows:
* = type-1 AGN
Note (2): The systemic redshift reported is derived from the Hα detection
in the integrated spectra. In case of no Hα detection (e.g. for
z>3 galaxies), the redshift is computed from [OIII].
--------------------------------------------------------------------------------
Byte-by-byte Description of file: table3.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 7 A7 --- Inst Spectrograph used for the observations
(SINFONI or KMOS)
9- 15 A7 --- Cluster Galaxy cluster
17- 40 A24 --- Name Galaxy name
42- 47 F6.2 Msun/yr SFR ? Star formation rate (1)
49- 53 F5.2 Msun/yr e_SFR ? Error on SFR
55- 56 A2 --- f_SFR [*/**/ ] Flag on SFR (2)
58- 62 F5.2 [Msun] logM* ? Logarithm of the stellar mass derived
by SED fitting
64- 67 F4.2 [Msun] e_logM* ? Error on logM*
69- 72 F4.2 --- 12+log(O/H) ? Oxygen abundance 12+log(O/H) (3)
74- 77 F4.2 --- E_12+log(O/H) ? Upper error on 12+log(O/H)
79- 82 F4.2 --- e_12+log(O/H) ? Lower error on 12+log(O/H)
84- 88 F5.2 --- muHa ? Magnification factor µHα (4)
90- 93 F4.2 --- e_muHa ? Error on muHa
95- 99 F5.2 --- mumaps ? Magnification factor µmaps (5)
101-105 F5.2 --- E_mumaps ? Upper error on mumaps
107-111 F5.2 --- e_mumaps ? Lower error on mumaps
--------------------------------------------------------------------------------
Note (1): Star formation rates are derived from the total Hα flux in the
image plane and corrected for magnification
Note (2): Flag as follows:
* = Total SFR derived from SINFONI observations of both the western and
southern arcs. The SFR computed for the western arc only, which is the
only region covered also by observations in the J and H bands, is
26.2±4.3M_☉/yr.
** = Hα not corrected for reddening due to absence of Hβ detection
Note (3): Metallicities are computed from the integrated spectra adopting the
Curti et al. (2017MNRAS.465.1384C 2017MNRAS.465.1384C, 2020MNRAS.491..944C 2020MNRAS.491..944C)
Note (4): µHα is derived from the ratio between the Hα flux in
the image plane and that in the source plane
Note (5): µmaps exploits the magnification maps computed, for each source
redshift, from the output files of the lens models adopted in this
work (Zitrin et al. 2013ApJ...762L..30Z 2013ApJ...762L..30Z, Cat. J/ApJ/762/L30)
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Byte-by-byte Description of file: table4.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 7 A7 --- Inst Spectrograph used for the observations
(SINFONI or KMOS)
9- 15 A7 --- Cluster Galaxy cluster
17- 40 A24 --- Name Galaxy name
42- 47 F6.3 kpc-1 Zgrad Metallicity gradient
49- 53 F5.3 kpc-1 e_Zgrad Error on Zgrad
55- 58 A4 --- Resol [Yes /Marg] Source resolution (1)
60- 63 F4.2 --- FWHMx Major-axis of the ellipse used to model the
PSF in the source plane
65- 68 F4.2 --- FWHMy Minor-axis of the ellipse used to model the
PSF in the source plane
70- 79 A10 --- Diag Combination of strong-line diagnostics adopted
to derive the metallicity map in the source
plane for each galaxy (2)
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Note (1): Resoltion as follows:
Yes = Galaxy where the gradient is extracted out to a radius larger than 2
times the linear size of the PSF-HWMH (sqrt(FWHMx*FWHMy))
Marg = Galaxy where the gradient is extracted within a radial distance
between 1 and 2 times this value
Note (2): Metallicity diagnostics as follows:
R3 = [OIII]λ5007/Hβ line ratio
N2 = [NII]λ6584/Hα line ratio
S2 = [SII]λλ6717,31/Hα line ratio
O3O2 = [OIII]λ5007/[OII]λλ3727,29 line ratio
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History:
From electronic version of the journal
(End) Ana Fiallos [CDS] 02-Mar-2023