J/ApJ/834/101 Keck/MOSFIRE spectroscopy of ZFOURGE galaxies (Tran+, 2017)
ZFIRE: similar stellar growth in Hα-emitting cluster and
field galaxies at z∼2.
Tran K.-V.H., Alcorn L.Y., Kacprzak G.G., Nanayakkara T., Straatman C.,
Yuan T., Cowley M., Dave R., Glazebrook K., Kewley L.J., Labbe I.,
Martizzi D., Papovich C., Quadri R., Spitler L.R., Tomczak A.
<Astrophys. J., 834, 101-101 (2017)>
=2017ApJ...834..101T 2017ApJ...834..101T (SIMBAD/NED BibCode)
ADC_Keywords: Galaxies, IR ; Spectra, infrared ; Redshifts ; Photometry, H-alpha
Keywords: galaxies: evolution; galaxies: starburst; galaxies: star formation
Abstract:
We compare galaxy scaling relations as a function of environment at
z∼2 with our ZFIRE survey where we have measured Hα fluxes for
90 star-forming galaxies selected from a mass-limited
(log(M*/M☉)>9) sample based on ZFOURGE. The cluster galaxies
(37) are part of a confirmed system at z=2.095 and the field galaxies
(53) are at 1.9<z<2.4; all are in the COSMOS legacy field. There is no
statistical difference between Hα-emitting cluster and field
populations when comparing their star formation rate (SFR), stellar
mass (M*), galaxy size (reff), SFR surface density
(Σ(Hαstar)), and stellar age distributions. The only
difference is that at fixed stellar mass, the Hα-emitting
cluster galaxies are log(reff)∼0.1 larger than in the field.
Approximately 19% of the Hα emitters in the cluster and 26% in
the field are IR-luminous (LIR>2x1011L☉). Because the
luminous IR galaxies in our combined sample are ∼5 times more massive
than the low-IR galaxies, their radii are ∼70% larger. To track
stellar growth, we separate galaxies into those that lie above, on, or
below the Hα star-forming main sequence (SFMS) using
ΔSFR(M*)=±0.2dex. Galaxies above the SFMS (starbursts) tend to
have higher Hα SFR surface densities and younger light-weighted
stellar ages than galaxies below the SFMS. Our results indicate that
starbursts (+SFMS) in the cluster and field at z∼2 are growing their
stellar cores. Lastly, we compare to the (SFR-M*) relation from
Rhapsody-G cluster simulations and find that the predicted slope is
nominally consistent with the observations. However, the predicted
cluster SFRs tend to be too low by a factor of ∼2, which seems to be a
common problem for simulations across environment.
Description:
Here we combine Hα emission from our ZFIRE survey (Nanayakkara+
2016, J/ApJ/828/21) with galaxy properties from the ZFOURGE survey
(Straatman+ 2016, J/ApJ/830/51) and IR luminosities from Spitzer to
track how galaxies grow at z∼2. ZFIRE is a near-IR spectroscopic
survey with MOSFIRE on Keck I where targets are selected from ZFOURGE,
an imaging survey that combines deep near-IR observations taken with
the FourStar Imager at the Magellan Observatory with public
multi-wavelength observations, e.g., Hubble Space Telescope (HST)
imaging from CANDELS (Grogin+ 2011ApJS..197...35G 2011ApJS..197...35G).
The Keck/MOSFIRE spectroscopy was obtained on observing runs in 2013
December and 2014 February. A total of eight slit masks were observed
in the K-band (1.93-2.38um). We also observed two masks in the H-band
covering 1.46-1.81um.
Objects:
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RA (ICRS) DE Designation(s)
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10 00 18.38 +02 14 58.0 galaxy cluster = [SLG2012] Galaxy Cluster
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File Summary:
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FileName Lrecl Records Explanations
--------------------------------------------------------------------------------
ReadMe 80 . This file
table1.dat 83 90 Galaxy properties
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See also:
VII/265 : COSMOS Morphological Catalog (V1.1) (Tasca+ 2009)
J/ApJ/830/51 : FourStar galaxy evolution survey (ZFOURGE) (Straatman+, 2016)
J/ApJ/828/21 : ZFIRE v1.0 data release (Nanayakkara+, 2016)
J/ApJ/817/118 : SFR-M* relation from ZFOURGE (Tomczak+, 2016)
J/ApJS/219/15 : Morphologies of z=0-10 galaxies with HST data (Shibuya+, 2015)
J/ApJS/218/33 : Spitzer-CANDELS catalog within 5 deep fields (Ashby+, 2015)
J/ApJS/214/24 : 3D-HST+CANDELS catalog (Skelton+, 2014)
J/ApJS/212/18 : An atlas of UV-to-MIR galaxy SEDs (Brown+, 2014)
J/ApJS/203/24 : Structural param. of galaxies in CANDELS (van der Wel+, 2012)
J/ApJ/682/985 : FIREWORKS photometry of GOODS CDF-S (Wuyts+, 2008)
J/ApJ/655/51 : HDFS IRAC observations of 2<z<3.5 galaxies (Wuyts+, 2007)
http://zfire.swinburne.edu.au/ : ZFIRE home page
http://zfourge.tamu.edu/ : ZFOURGE home page
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 4 I4 --- ZFIRE [237/9922] ZFIRE source identifier (1)
6- 10 I5 --- ZFOURGE [912/14346] ZFOURGE source identifier (1)
12- 20 F9.5 deg RAdeg Right Ascension in decimal degrees (J2000)
22- 28 F7.5 deg DEdeg Declination in decimal degrees (J2000)
30- 35 F6.4 --- zsp [1.9/2.4] Spectroscopic redshift
37- 41 F5.2 10-20W/m2 FHa [0.4/11.2] Observed Hα flux,
10-17erg/s/cm2
43- 46 F4.2 10-20W/m2 e_FHa [0.05/0.3] Uncertainty in FHa
48- 52 F5.2 [Lsun] LIR [8.7/12.3]? Log of IR luminosity (2)
54- 58 F5.2 [Msun] Mstar [8.9/11] Log of stellar mass
60- 62 F3.1 mag Av [0/1.6] Extinction
64- 66 F3.1 [Gyr] t [7.9/9.4] Log of stellar age (3)
68- 71 F4.1 Msun/yr SFR [1/84] Hα based star formation
rate (4)
73- 75 F3.1 --- n [0.3/8]? Sersic index
77- 79 F3.1 arcsec Reff [0.1/0.9]? Effective radius
81- 83 I3 --- Pflag [-99/2]? Quality of profile fit
(0=good fit) (5)
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Note (1): Galaxy identification numbers from ZFIRE (Nanayakkara+
2016, J/ApJ/828/21) and ZFOURGE (Straatman+ 2016, J/ApJ/830/51).
We include only galaxies with spectroscopic redshift quality flag of
Q_z=3 (Nanayakkara+ 2016, J/ApJ/828/21) and 1.9<zsp<2.4.
Cluster members (37 galaxies) have 2.08<zsp<2.12 (Yuan+ 2014ApJ...795L..20Y 2014ApJ...795L..20Y).
Note (2): In our analysis of IR-luminous vs. low-IR systems, we select
IR-luminous galaxies using log(LIR/Lsun)>11.3.
Note (3): Stellar age in units of Gyr and based on SED fitting with FAST
(Kriek et al., 2009ApJ...700..221K 2009ApJ...700..221K).
Note (4): Hα star formation rates in units of Msun/yr and based on
dust-corrected Hα fluxes (Eq. 2; see Section 2.4).
Note (5): Quality of profile fit used to measure the Sersic index, n, and
the effective radius, Reff as follows:
-99 = not fit;
0 = good fit;
1 = fair fit;
2 = questionable fit.
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History:
From electronic version of the journal
(End) Prepared by [AAS], Emmanuelle Perret [CDS] 02-Jun-2017