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J/ApJ/617/240   Oxygen abundances in the GOODS-North field   (Kobulnicky+, 2004)

Metallicities of 0.3<z<1.0 galaxies in the GOODS-North field. Kobulnicky H.A., Kewley L.J. <Astrophys. J., 617, 240-261 (2004)> =2004ApJ...617..240K
ADC_Keywords: Abundances ; Equivalent widths ; Galaxies, photometry Keywords: galaxies: abundances - galaxies: evolution - galaxies: fundamental parameters - galaxies: starburst - H II regions - ISM: abundances Abstract: We measure nebular oxygen abundances for 204 emission-line galaxies with redshifts 0.3<z<1.0 in the Great Observatories Origins Deep Survey-North (GOODS-N) field using spectra from the Team Keck Redshift Survey, Cat. J/AJ/127/3121. We also provide an updated analytic prescription for estimating oxygen abundances using the traditional strong emission line ratio, R23, based on the photoionization models of Kewley & Dopita (2002ApJS..142...35K). We include an analytic formula for very crude metallicity estimates using the [NII]λ6584/Hα ratio. File Summary:
FileName Lrecl Records Explanations
ReadMe 80 . This file table1.dat 170 204 GOOD-North TKRS selected galaxies
See also: J/ApJ/600/L93 : GOODS initial results (Giavalisco+, 2004) J/AJ/127/3121 : TKRS survey of the GOODS-North field (Wirth+, 2004) Byte-by-byte Description of file: table1.dat
Bytes Format Units Label Explanations
1- 3 I3 --- [KK2004b] Identification number 5- 9 I5 --- TKRS TKRS identifier (Wirth et al., Cat. J/AJ/127/3121) 11- 29 A19 --- GOODS GOODS-N v1.0 catalog identifier 31- 37 F7.5 --- z TKRS spectroscopic redshift 39- 43 F5.2 mag Rmag TKRS R-band magnitude (648.7±81nm, AB system) 45- 49 F5.2 mag imag GOODS-N v1.0 i band F775W magnitude 51- 56 F6.2 mag BMAG Rest frame absolute B band magnitude (1) 58- 62 F5.3 mag U-B Rest frame (U-B) color index 64- 68 F5.1 0.1nm EWOII The [OII](3727) equivalent width (2) 70- 73 F4.1 0.1nm e_EWOII Uncertainty in EWOII 75- 78 F4.1 0.1nm EWHb The Hβ(4861) equivalent width (3) 80- 82 F3.1 0.1nm e_EWHb Uncertainty in EWHb 84- 88 F5.1 0.1nm EWOIII The [OIII](4959+5007) equivalent width (4) 90- 93 F4.1 0.1nm e_EWOIII Uncertainty in EWOIII 95 A1 --- l_EWHa/NII Limit flag on EWHa/NII 97-101 F5.2 0.1nm EWHa/NII ? Measured Hα/[NII](6584) equivalent width ratio (2) 103-107 F5.2 solMass/yr SFR Estimated star formation rate (5) 109 I1 --- Code Code about oxygen abundance derivation (6) 111-115 F5.2 [-] log(O32) Log of the ratio of the oxygen lines (7) 117-121 F5.2 --- R23 Traditional strong emission line ratio (8) 123 A1 --- l_(O/H)M91 Limit flag on (O/H)M91 125-128 F4.2 [-] (O/H)M91 McGaugh (1991ApJ...380..140M) Oxygen abundance, 12+log(O/H) (9) 130-133 F4.2 [-] e_(O/H)M91 ? The 1σ error in (O/H)M91 135 A1 --- l_(O/H)KD Limit flag on (O/H)KD 137-140 F4.2 [-] (O/H)KD Kewley & Dopita (2002ApJS..142...35K) oxygen abundance, 12+log(O/H) (10) 142 A1 --- l_(O/H)avg Limit flag on (O/H)avg 144-147 F4.2 [-] (O/H)avg Mean (O/H)M91 and (O/H)KD abundance 149 A1 --- l_(O/H)NII Limit flag on (O/H)NII 151-154 F4.2 [-] (O/H)NII ? Oxygen abundance, 12+log(O/H), using O32 and the [NII]/Hα ratio (11) 156 A1 --- l_O/H Limit flag on O/H 158-161 F4.2 [-] O/H Oxygen abundance, 12+log(O/H) (12) 163-166 F4.2 [-] e_O/H ? Error in O/H
Note (1): H0=70km/s/Mpc, ΩM=0.3, ΩΛ=0.7. Note (2): Corrected to the rest frame. Note (3): Corrected to the rest frame but no correction for stellar absorption. Note (4): Determined from 1.3*W_[O III]_(5007) and uncertainty, corrected to the rest frame; Note (5): Based on Hβ flux (not corrected for stellar absorption), derived from the EWHb and BMag. We estimate the Hβ luminosity as L(erg/s)=5.49E31*2.5-BMag*EWHb. The SFR then is computed by SFR(SolMass/yr)=2.8*L/1.26E41 which assumes the Kennicutt (1998ApJ...498..541K) calibration of SFR in terms of Hα luminosity. This estimate is a lower limit since dust extinction and stellar Balmer absorption are not taken into account. Note (6): Code, defined as follows: 0 = oxygen abundance computed using EWR23=(W[OII](3727)+1.3*W[OIII](5007))/W; 1 = object is probably on the turnaround region of the R23-O/H calibration or possibly on the lower branch based on the [NII](6584)/Hα ratio, so lower branch formula of McGaugh (1991ApJ...380..140M) is applied and averaged with the upper branch estimate of KD02 to arrive at the oxygen abundance in (O/H)avg; 2 = oxygen abundance computed using EWR23=(W[OII](3727)+4*W[OIII](4959))/W; 3 = W[OIII](5007) is measured with signal-to-noise <3:1 so a 3σ lower limit on the oxygen abundance is computed using EWR23 = (W[OII](3727)+1.3*W[OIII](5007))/W; Note (7): log(O32)=1.3*W[OIII](5007)/W[OII](3727); Note (8): R23=EWR23=(W[OIII](3727)+1.3*W[OII](5007))/W Note (9): From the empirical R23 method following McGaugh (1991ApJ...380..140M) as formulated in KKP after correction for 2 Angstroms of stellar absorption in the EW. The uncertainty reflects statistical measurement error on the line EWs only, and does not include systematic uncertainties in the calibration method which may exceed 0.1dex in 12+log(O/H); Note (10): Based on the EWR23 and the models of Kewley & Dopita (2002ApJS..142...35K) as given in equations in the text; Note (11): Estimated using O32 and the [NII]/Hα ratio in conjunction with the photoionization models and parametric relations of equation 12 and 13; Note (12): This is simply the value from (O/H)avg in most cases. For objects with code=1 that are on the lower branch or turnaround region of the R23-O/H calibration, this value is the average of (O/H)M91 and (O/H)KD. See text and Garnett, Kennicutt, & Bresolin (2004ApJ...607L..21G) for possible systematic uncertainties in the absolute metallicities which may reach 0.2-0.5dex, particularly in metal-rich systems.
History: From electronic version of the journal
(End) Greg Schwarz [AAS], Marianne Brouty [CDS] 23-Jun-2005
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