J/ApJ/840/78 Redshift survey of ALMA-identified SMGs in ECDFS (Danielson+, 2017)
An ALMA survey of submillimeter galaxies in the Extended Chandra Deep Field
South: spectroscopic redshifts.
Danielson A.L.R., Swinbank A.M., Smail I., Simpson J.M., Casey C.M.,
Chapman S.C., da Cunha E., Hodge J.A., Walter F., Wardlow J.L.,
Alexander D.M., Brandt W.N., de Breuck C., Coppin K.E.K., Dannerbauer H.,
Dickinson M., Edge A.C., Gawiser E., Ivison R.J., Karim A., Kovacs A.,
Lutz D., Menten K., Schinnerer E., Weiss A., van der Werf P.
<Astrophys. J., 840, 78 (2017)>
=2017ApJ...840...78D 2017ApJ...840...78D
ADC_Keywords: Galaxies, spectra ; Redshifts ; Surveys
Keywords: galaxies: evolution; galaxies: formation; galaxies: high redshift;
galaxies: starburst
Abstract:
We present spectroscopic redshifts of S870µm≳2mJy submillimeter
galaxies (SMGs), which have been identified from the ALMA follow-up
observations of 870µm detected sources in the Extended Chandra Deep
Field South (the ALMA-LESS survey). We derive spectroscopic redshifts
for 52 SMGs, with a median of z=2.4±0.1. However, the distribution
features a high-redshift tail, with ∼23% of the SMGs at z≥3. Spectral
diagnostics suggest that the SMGs are young starbursts, and the
velocity offsets between the nebular emission and UV ISM absorption
lines suggest that many are driving winds, with velocity offsets of up
to 2000km/s. Using the spectroscopic redshifts and the extensive
UV-to-radio photometry in this field, we produce optimized spectral
energy distributions (SEDs) using Magphys, and use the SEDs to infer a
median stellar mass of M*=(6±1)x1010M☉ for our SMGs with
spectroscopic redshift. By combining these stellar masses with the
star formation rates (measured from the far-infrared SEDs), we show
that SMGs (on average) lie a factor of ∼5 above the so-called "main
sequence" at z∼2. We provide this library of 52 template fits with
robust and uniquely well-sampled SEDs as a resource for future studies
of SMGs, and also release the spectroscopic catalog of ∼2000 (mostly
infrared-selected) galaxies targeted as part of the spectroscopic
campaign.
Description:
The 870um LESS survey (Weiss+ 2009, J/ApJ/707/1201) was undertaken
using the LABOCA camera on APEX, covering an area of 0.5°x0.5°
centered on the ECDFS. Follow-up observations of the LESS sources were
carried out with ALMA (Hodge+ 2013, J/ApJ/768/91). In summary,
observations for each source were taken between 2011 October and
November in the Cycle 0 Project #2011.1.00294.S.
To search for spectroscopic redshifts, we initiated an observing
campaign using the the FOcal Reducer and low dispersion Spectrograph
(FORS2) and VIsible MultiObject Spectrograph (VIMOS) on VLT (program
183.A-0666), but to supplement these observations, we also obtained
observations with XSHOOTER on VLT (program 090.A-0927(A) from 2012
December 7-10), the Gemini Near-Infrared Spectrograph (GNIRS; program
GN-2012B-Q-90) and the Multi-Object Spectrometer for Infra-Red
Exploration (MOSFIRE) on the Keck I telescope (2012B_H251M,
2013B_U039M, and 2013B_N114M), all of which cover the near-infrared.
As part of a spectroscopic campaign targeting Herschel-selected
galaxies in the ECDFS, ALESS submillimeter galaxies (SMGs) were
included on DEep Imaging Multi-Object Spectrograph (DEIMOS) slit masks
on Keck II (program 2012B_H251). In total, we observed 109 out of the
131 ALESS SMGs in the combined main and supp samples.
Spectroscopic redshifts for two of our SMGs, ALESS61.1 and ALESS65.1,
were determined from serendipitous detections of the [CII]λ158um
line in the ALMA band. See section 2.7.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 45 1708 Spectroscopic redshifts for the full sample
table2.dat 295 109 ALESS observed submillimeter galaxies (SMGs)
spectroscopic redshift catalog
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See also:
III/250 : The VIMOS VLT deep survey (VVDS-DEEP) (Le Fevre+ 2005)
VIII/95 : Herschel Multi-tiered Extragalactic Survey (Oliver+, 2012)
J/ApJ/600/L99 : Colours of z∼6 galaxies in GOODS (Dickinson+, 2004)
J/ApJ/616/71 : Optical properties of SCUBA galaxies (Smail+, 2004)
J/ApJ/613/200 : Hubble Higher z Supernova Search, HHZSS (Strolger+, 2004)
J/ApJS/155/271 : CDF-South: Optical spectroscopy (Szokoly+, 2004)
J/ApJ/622/772 : Redshift survey of submillimeter galaxies (Chapman+, 2005)
J/MNRAS/361/525 : Las Campanas Infrared Survey. V. (Doherty+, 2005)
J/ApJS/161/21 : Extended Chandra Deep Field-South survey (Lehmer+, 2005)
J/A+A/437/883 : K20 survey: spectroscopic catalogue (Mignoli+, 2005)
J/ApJ/647/128 : Hα observations of UV-selected galaxies (Erb, 2006)
J/MNRAS/380/199 : SCUBA Half-Degree Extragalactic Survey. III (Ivison+, 2007)
J/A+A/465/1099 : Redshift catalog of 691 objects in CDFS (Ravikumar+, 2007)
J/ApJS/179/19 : CDFS survey: 2 Ms source catalogs (Luo+, 2008)
J/A+A/478/83 : GOODS-S Field VLT/FORS2 redshifts. III. (Vanzella+, 2008)
J/A+A/497/81 : Variability-selected AGN in CDFS (Boutsia+, 2009)
J/ApJ/699/1610 : Spitzer survey of submillimeter galaxies (Hainline+, 2009)
J/ApJS/183/295 : A K-selected catalog of the ECDFS from MUSYC (Taylor+, 2009)
J/ApJ/693/1713 : Spectroscopy of X-ray sources in ECDF-S (Treister+, 2009)
J/ApJ/707/1201 : LABOCA ECDFS Submillimeter Survey (LESS) (Weiss+, 2009)
J/A+A/512/A12 : VLT/VIMOS spectroscopy in GOODS-S field (Balestra+, 2010)
J/ApJS/191/124 : Opt. spectroscopy of ECDF-S X-ray sources (Silverman+, 2010)
J/MNRAS/413/2314 : Radio & MIR counterpart of submm galaxies (Biggs+, 2011)
J/ApJ/740/37 : Obscured AGN at z∼0.5-1 in the CDFS (Luo+, 2011)
J/A+A/532/A90 : PACS Evolutionary Probe (PEP-DR1) catalogs (Lutz+, 2011)
J/MNRAS/415/1479 : LESS photometric redshift survey (Wardlow+, 2011)
J/AJ/141/64 : PEARS emission-line galaxies spectroscopy (Xia+, 2011)
J/ApJS/203/15 : Counterparts to 1.4GHz sources in ECDF-S (Bonzini+, 2012)
J/ApJ/761/140 : Spectroscopy of Herschel-SPIRE galaxies (Casey+, 2012)
J/MNRAS/426/3334 : Australia Telescope Large Area Survey (Mao+, 2012)
J/ApJ/768/91 : ALMA observations of LESS submm galaxies (Hodge+, 2013)
J/A+A/549/A63 : GMASS photometry (Kurk+, 2013)
J/ApJ/788/125 : An ALMA survey of ECDFS submm galaxies (Simpson+, 2014)
J/ApJ/806/110 : ALESS survey: SMGs in the ECDF-S data (da Cunha+, 2015)
J/ApJ/820/82 : S2CLS: multiwavelength counterparts to SMGs (Chen+, 2016)
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 8 A8 --- ID Identifier
10- 17 F8.5 deg RAdeg Right Ascension in decimal degrees (J2000)
19- 27 F9.5 deg DEdeg Declination in decimal degrees (J2000)
29- 37 E9.5 --- zspec [0/5.7]? Spectroscopic redshift
39 I1 --- q_zspec Quality flag for zspec (1=secure) (G1)
41- 45 A5 --- Inst Instruments used (G2)
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Byte-by-byte Description of file: table2.dat
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Bytes Format Units Label Explanations
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1- 5 A5 --- --- [ALESS]
7- 12 A6 --- ALESS ALESS identifier (1)
14 A1 --- f_ALESS [i] i = A supplementary SMGs source
16- 24 F9.6 deg RAdeg Right Ascension in decimal degrees (J2000)
26- 35 F10.6 deg DEdeg Declination in decimal degrees (J2000)
37- 42 F6.4 --- zspec [0.6/5]? Spectroscopic redshift
44 A1 --- f_zspec [d] Flag on zspec (2)
46 I1 --- q_zspec Quality flag for zspec (1=secure) (G1)
48- 51 F4.2 --- zphot [0.3/7]? Photometric redshift
from Simpson+ (2014,J/ApJ/788/125)
53- 57 F5.2 --- E_zphot ? Upper uncertainty in zphot
59- 62 F4.2 --- e_zphot ? Lower uncertainty in zphot
64 A1 --- Set Source; M(ain) or S(upplementary) catalogs
66- 74 A9 --- Inst Instruments used (G2)
76-295 A220 --- Notes Additional notes
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Note (1): The 22 ALESS SMGs not targeted in our spectroscopy programme
(and without redshifts from literature) are not listed here.
Note (2):
d = These redshifts are for the six sources which also have literature
spectroscopic redshifts described in Section 3.
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Global notes:
Note (G1): Quality flag as follows:
1 = secure redshifts;
2 = redshifts measured from only one or two strong lines;
3 = tentative redshifts measured based on one or two very faint features;
4 = sources which were targeted but no redshift could be determined.
Note (G2): Instrument as follows:
F = VLT/FORS2;
V = VLT/VIMOS;
X = VLT/XSHOOTER;
M = Keck/MOSFIRE (Band H or K);
D = Keck/DEIMOS;
G = Gemini/GNIRS.
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History:
From electronic version of the journal
Acknowledgements:
Mark Swinbank (a.m.swinband followed by durham.ac.uk)
(End) Prepared by [AAS], Emmanuelle Perret [CDS] 11-Dec-2017