J/AJ/149/79 Spectroscopy of 299 galaxies from NewHa survey (de los Reyes+, 2015)
The relationship between stellar mass, gas metallicity, and star formation rate
for Hα-selected galaxies at z ≈ 0.8 from the NewHα survey.
de los Reyes M.A., Ly C., Lee J.C., Salim S., Peeples M.S., Momcheva I.,
Feddersen J., Dale D.A., Ouchi M., Ono Y., Finn R.
<Astron. J., 149, 79 (2015)>
=2015AJ....149...79D 2015AJ....149...79D
ADC_Keywords: Galaxies, photometry ; Galaxies, spectra ; Interstellar medium ;
Photometry, infrared ; Redshifts ; Equivalent widths ;
Abundances ; Balmer lines
Keywords: galaxies: abundances - galaxies: evolution -
galaxies: fundamental parameters - galaxies: ISM - galaxies: starburst
Abstract:
Using a sample of 299 Hα-selected galaxies at z≈0.8, we study
the relationship between galaxy stellar mass, gas-phase metallicity,
and star formation rate (SFR), and compare to previous results. We use
deep optical spectra obtained with the IMACS spectrograph at the
Magellan telescope to measure strong oxygen lines. We combine these
spectra and metallicities with (1) rest-frame UV-to-optical imaging,
which allows us to determine stellar masses and dust attenuation
corrections, and (2) Hα narrowband imaging, which provides a
robust measurement of the instantaneous SFR. Our sample spans stellar
masses of ∼109-6x1011M☉, SFRs of 0.4-270M☉/yr, and
metal abundances of 12+log(O/H)≈8.3-9.1(≈0.4-2.6Z☉). The
correlations that we find between the Hα-based SFR and stellar
mass (i.e., the star-forming "main sequence") and between the stellar
mass and metallicity are both consistent with previous z∼1 studies of
star-forming galaxies. We then study the relationship between the
three properties using various plane-fitting techniques and a
curve-fitting projection. In all cases, we exclude strong dependence
of the M*-Z relation on SFR, but are unable to distinguish
between moderate and no dependence. Our results are consistent with
previous mass-metallicity-SFR studies. We check whether data set
limitations may obscure a strong dependence on the SFR by using mock
samples drawn from the Sloan Digital Sky Survey. These experiments
reveal that the adopted signal-to-noise ratio cuts may have a
significant effect on the measured dependence. Further work is needed
to investigate these results, and to test whether a "fundamental
metallicity relation" or a "fundamental plane" describes star-forming
galaxies across cosmic time.
Description:
We present near-infrared narrowband photometry and optical
spectroscopy for a sample of 299 Hα-selected galaxies at z∼0.8
from the National Optical Astronomy Observatory (NOAO) Extremely
Wide-Field Infrared Imager (NEWFIRM) Hα survey (NewHα; Ly
et al., 2011ApJ...726..109L 2011ApJ...726..109L; Lee et al., 2012PASP..124..782L 2012PASP..124..782L). The
galaxies are identified in the Subaru/XMM Deep Survey (SXDS) field
(Furusawa et al. 2008, cat. J/ApJS/176/1). The NewHα Survey is a
program that has obtained emission-line selected samples at
intermediate redshift.
NEWFIRM at the Kitt Peak National Observatory/Cerro Tololo
Inter-American Observatory (KPNO/CTIO) 4m telescopes was used to
obtain observations over three fields (that roughly correspond with
the Subaru/Suprime-Cam South, West, and North pointings) in the SXDS
(α=2h18m; δ=-5°) in 2007 December, 2008 September,
and 2008 October.
As discussed in Momcheva et al. (2013AJ....145...47M 2013AJ....145...47M), deep follow-up
spectroscopy of the NewHα narrowband 1.18µm (NB118)
emission-line galaxy candidate sample was performed in 2008-2009 with
the Inamori Magellan Areal Camera and Spectrograph (IMACS) on the
Magellan-I 6.5m Baade telescope. The chosen observational setup yields
spectral coverage from 6300 to 9600Å (corresponding to rest frame
∼3500-5300Å), and captures the strong rest-frame optical emission
lines from [OII] λ3727 (observed at ∼6700Å) to [OIII]
λ5007 (observed at ∼9000Å) for galaxies at z∼0.8. Slit
widths of 1.5'' were chosen (∼11kpc at z=0.8). The seeing during our
observing runs was generally sub-arcsecond. In Table 1, we present the
NEWFIRM photometric properties of the 299 spectroscopically confirmed
Hα emitters in the SXDS with IMACS.
We use multiband photometry (GALEX NUV, Canada-France-Hawaii Telescope
(CFHT)/Megacam u-band, Subaru/Suprime-Cam BVRCi'z' and J) as
constraints in the Spectral Energy Distribution (SED) fitting (which
is discussed in Section 3.1). The NUV photometry are based on deep
(46ks) GALEX imaging of the SXDS fields (PI: S. Salim, GI6-005). The
optical photometry was obtained with Suprime-Cam as part of the Subaru
Telescope Observatory Projects (Furusawa et al. 2008, cat.
J/ApJS/176/1).
File Summary:
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FileName Lrecl Records Explanations
--------------------------------------------------------------------------------
ReadMe 80 . This file
table1.dat 99 299 NEWFIRM photometry of Hα-selected z=0.8 galaxies
table2.dat 82 299 NewHα emission-line fluxes from Magellan/IMACS
table3.dat 59 299 Stellar mass, SFR, and AGN classification
table4.dat 79 187 NewHα SED-corrected metallicities
table5.dat 79 187 NewHα Balmer-corrected metallicities
--------------------------------------------------------------------------------
See also:
J/ApJ/765/140 : Stacked spectra of SDSS star forming galaxies (Andrews+, 2013)
J/ApJ/735/86 : NEWFIRM MBS: photometric catalogs (Whitaker+, 2011)
J/ApJ/677/169 : Hα galaxies at z=0.84 (Villar+, 2008)
J/ApJS/176/1 : Subaru/XMM-Newton deep survey (SXDS). II. (Furusawa+, 2008)
J/ApJ/657/738 : SDF galaxies multi-photometry (Ly+, 2007)
J/A+A/459/85 : O/H and gas densities in star-forming galaxies (Nagao+, 2006)
J/ApJ/617/240 : Oxygen abundances in the GOODS-North field (Kobulnicky+, 2004)
Byte-by-byte Description of file: table1.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1 A1 --- Fld Field in the Subaru/XMM Deep Survey (SXDS)
(S=South, N=North, W=West) (G1)
3- 6 A4 --- --- [SXDS]
7- 13 A7 --- SXDS Identifier in the NEWFIRM Hα
(NewHα) survey catalog (G2)
15 I1 h RAh Hour of Right Ascension (J2000)
17- 18 I2 min RAm Minute of Right Ascension (J2000)
20- 23 F4.1 s RAs Second of Right Ascension (J2000)
25 A1 --- DE- Sign of the Declination (J2000)
26 I1 deg DEd Degree of Declination (J2000)
28- 29 I2 arcmin DEm Arcminute of Declination (J2000)
31- 34 F4.1 arcsec DEs Arcsecond of Declination (J2000)
36- 40 F5.3 --- z [0.78/0.83] IMACS spectroscopic redshift (1)
42 A1 --- l_Jmag Limit on Jmag
44- 48 F5.2 mag Jmag [18.6/23.7]? NEWFIRM J band AB magnitude (2)
50- 53 F4.2 mag e_Jmag ? Uncertainty in Jmag
55 A1 --- l_NBmag Limit flag on NBmag
57- 61 F5.2 mag NBmag [18.23/23.41]? NEWFIRM narrowband 1.18µm
AB magnitude (3)
63- 66 F4.2 mag e_NBmag ? Uncertainty in NBmag
68- 72 F5.1 10-20W/m2 Flux [1/125.7]? Narrowband flux; in units of
10-17erg/s/cm2 (4)
74- 77 F4.1 10-20W/m2 e_Flux ? Uncertainty in Flux
79 A1 --- l_EW Limit flag on EW
80- 83 I4 0.1nm EW [5/270]? Narrowband rest-frame equivalent
width; in Å
85- 87 I3 0.1nm e_EW ? Uncertainty in EW
89- 92 F4.2 --- NII/Ha ? Estimated [NII] to Hα flux ratio (5)
94- 99 F6.3 [10-7W] logLHa [40.368/42.427]? Log observed Hα
luminosity; in erg/s (4)
--------------------------------------------------------------------------------
Note (1): IMACS = Inamori Magellan Areal Camera and Spectrograph on the
Magellan-I 6.5m Baade telescope.
Note (2): NEWFIRM = National Optical Astronomy Observatory (NOAO) Extremely
Wide-Field Infrared Imager (at the Kitt Peak National Observatory/Cerro
Tololo Inter-American Observatory (KPNO/CTIO) 4m telescopes). The
conversion from Vega to AB magnitudes is given by m(AB)-m(Vega)=0.87
(Ly et al., 2011ApJ...726..109L 2011ApJ...726..109L).
Note (3): The conversion from Vega to AB magnitudes is given by
m(AB)-m(Vega)=0.95 (Ly et al., 2011ApJ...726..109L 2011ApJ...726..109L).
Note (4): For both flux and luminosity, the amount of foreground extinction is
negligible, so we excluded it in our calculations.
Note (5): Calculated using the narrowband equivalent width (refer to Section 3.2
for more details). Here, [NII] refers to the doublet, 6548 and 6583Å.
--------------------------------------------------------------------------------
Byte-by-byte Description of file: table2.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1 A1 --- Fld Field in the Subaru/XMM Deep Survey (SXDS)
(S=South, N=North, W=West) (G1)
3- 6 A4 --- --- [SXDS]
7- 13 A7 --- SXDS Identifier in the NEWFIRM Hα
(NewHα) survey catalog (G2)
15- 19 F5.2 10-20W/m2 FOII ? Magellan/IMACS spectroscopic flux for the
[OII]λ3726+3729Å emission-line (6)
21- 24 F4.2 10-20W/m2 e_FOII ? Uncertainty in FOII
26- 31 F6.2 10-20W/m2 F4959 ? Magellan/IMACS spectroscopic flux for the
[OIII]λ4959Å emission-line (6)
33- 36 F4.2 10-20W/m2 e_F4959 ? Uncertainty in F4959
38- 43 F6.2 10-20W/m2 F5007 ? Magellan/IMACS spectroscopic flux for the
[OIII]λ5007Å emission-line (6)
45- 48 F4.2 10-20W/m2 e_F5007 ? Uncertainty in F5007
50- 55 F6.2 10-20W/m2 FHb ? Magellan/IMACS spectroscopic flux for
Balmer Hβ emission-line (6)
57- 60 F4.2 10-20W/m2 e_FHb ? Uncertainty in FHb
62- 66 F5.2 10-20W/m2 FHg ? Magellan/IMACS spectroscopic flux for the
Balmer Hγ emission-line (6)
68- 71 F4.2 10-20W/m2 e_FHg ? Uncertainty in FHg
73- 77 F5.2 10-20W/m2 FHd ? Magellan/IMACS spectroscopic flux for the
Balmer Hδ emission-line (6)
79- 82 F4.2 10-20W/m2 e_FHd ? Uncertainty in FHd
--------------------------------------------------------------------------------
Note (6): IMACS = Inamori Magellan Areal Camera and Spectrograph on the
Magellan-I 6.5m Baade telescope. All line fluxes are in units of
10-17erg/s/cm2.
--------------------------------------------------------------------------------
Byte-by-byte Description of file: table3.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1 A1 --- Fld Field in the Subaru/XMM Deep Survey (SXDS)
(S=South, N=North, W=West) (G1)
3- 6 A4 --- --- [SXDS]
7- 13 A7 --- SXDS Identifier in the NEWFIRM Hα
(NewHα) survey catalog (G2)
15- 19 F5.2 [Msun] logM* ? Log stellar mass determination (7)
21- 24 F4.2 [Msun] e_logM* ? Uncertainty in logM (8)
26- 30 F5.2 [Msun/yr] SFRSED ? Log star formation rate from spectral
energy distribution (SED) fitting (9)
32- 35 F4.2 [Msun/yr] e_SFRSED ? Uncertainty in SFRSED
37- 41 F5.2 [Msun/yr] SFRHaS ? Log star formation rate from Hα
luminosity (10)
43- 46 F4.2 [Msun/yr] e_SFRHaS ? Uncertainty in SFRHaS
48- 52 F5.2 [Msun/yr] SFRHaB ? Log star formation rate from Hα
luminosity (11)
54- 57 F4.2 [Msun/yr] e_SFRHaB ? Uncertainty in SFRHaB
59 I1 --- AGN [1/1]?=0 Denotes an Active Galactic Nucleus
(AGN) (12)
--------------------------------------------------------------------------------
Note (7): As described in Section 3.1. Blanks indicate weak measurements.
Note (8): The uncertainties include errors from input photometry and parameter
degeneracy (e.g., with respect to star formation history and dust).
Note (9): As described in Section 3.2. Blanks indicate weak measurements.
Note (10): As described in Section 3.2. Dereddened using the prescription of
Charlot & Fall (2000ApJ...539..718C 2000ApJ...539..718C) and spectral energy distribution (SED)
results. Blanks indicate weak measurements.
Note (11): As described in Section 3.2. Dereddened using the Balmer decrement.
Blanks indicate weak measurements.
Note (12): AGN classification was performed by Momcheva et al.
(2013AJ....145...47M 2013AJ....145...47M) using a combination of methods, including UV
variability, line widths, and emission-line diagnostics with the
"Mass-Excitation" diagram (Juneau et al., 2011ApJ...736..104J 2011ApJ...736..104J), to identify
both broad- and narrow-line AGNs.
--------------------------------------------------------------------------------
Byte-by-byte Description of file: table[45].dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1 A1 --- Fld Field in the Subaru/XMM Deep Survey (SXDS)
(S=South, N=North, W=West) (G1)
3- 6 A4 --- --- [SXDS]
7- 13 A7 --- SXDS Identifier in the NEWFIRM Hα (NewHα)
survey catalog (G2)
15- 19 F5.3 [-] ZM91+ [7.595/9.093]? Upper metallicity Z from calibration
of McGaugh (1991ApJ...380..140M 1991ApJ...380..140M) (1)
21- 25 F5.3 [-] e_ZM91+ ? Uncertainty in ZM91+
27- 31 F5.3 [-] ZM91- [6.776/9.061]? Lower metallicity Z from calibration
of McGaugh (1991ApJ...380..140M 1991ApJ...380..140M) (1)
33- 37 F5.3 [-] e_ZM91- ? Uncertainty in ZM91-
39- 43 F5.3 [-] ZZ94 [7.102/9.324]? Metallicity Z from calibration of
Zaritsky et al. (1994ApJ...420...87Z 1994ApJ...420...87Z) (1)
45- 49 F5.3 [-] e_ZZ94 ? Uncertainty in ZZ94
51- 55 F5.3 [-] ZT04 [7.634/9.24]? Metallicity Z from calibration of
Tremonti et al. (2004ApJ...613..898T 2004ApJ...613..898T) (1)
57- 61 F5.3 [-] e_ZT04 ? Uncertainty in ZT04
63- 67 F5.3 [-] ZN06 [8.163/9.238]? Metallicity Z from calibration of
Nagao et al. 2006 (cat. J/A+A/459/85) (1)
69- 73 F5.3 [-] ZKK04+ [7.361/9.155]? Upper metallicity Z from calibration
of Kobulnicky & Kewley 2004 (J/ApJ/617/240) (1)
75- 79 F5.3 [-] ZKK04- [7.242/9.071]? Lower metallicity Z from calibration
of Kobulnicky & Kewley 2004 (J/ApJ/617/240) (1)
--------------------------------------------------------------------------------
Note (1): All metallicities are reported in form Z=12+log(O/H) and are
calculated using the nebular emission lines reported in Table 2, with dust
attenuation correction derived from the SED fitting (Table 4) and the
Balmer decrement (Hγ/Hβ) (Table 5).
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Global Notes:
Note (G1): The Subaru/XMM Deep Survey (SXDS) fields observed by the National
Optical Astronomy Observatory (NOAO) Extremely Wide-Field Infrared Imager
(NEWFIRM) at the Kitt Peak National Observatory (KPNO) 4m Mayall telescope
roughly correspond with the Suprime-Cam South, West, and North pointings.
Note (G2): Spectroscopically confirmed Hα emitters in the Subaru/XMM Deep
Survey (SXDS) with Inamori Magellan Areal Camera and Spectrograph (IMACS)
on the Magellan-I 6.5m Baade telescope.
History:
From electronic version of the journal
(End) Greg Schwarz [AAS], Sylvain Guehenneux [CDS] 09-Mar-2015