J/ApJ/832/78 SCUBA-2 & LABOCA obs. of HATLAS ultrared galaxies (Ivison+, 2016)
The space density of luminous dusty star-forming galaxies at z>4: SCUBA-2 and
LABOCA imaging of ultrared galaxies from Herschel-ATLAS.
Ivison R.J., Lewis A.J.R., Weiss A., Arumugam V., Simpson J.M.,
Holland W.S., Maddox S., Dunne L., Valiante E., van der Werf P., Omont A.,
Dannerbauer H., Smail I., Bertoldi F., Bremer M., Bussmann R.S., Cai Z.-Y.,
Clements D.L., Cooray A., De Zotti G., Eales S.A., Fuller C.,
Gonzalez-Nuevo J., Ibar E., Negrello M., Oteo I., Perez-Fournon I.,
Riechers D., Stevens J.A., Swinbank A.M., Wardlow J.
<Astrophys. J., 832, 78 (2016)>
=2016ApJ...832...78I 2016ApJ...832...78I
ADC_Keywords: Galaxies, IR; Photometry, millimetric/submm; Redshifts
Keywords: galaxies: high-redshift ; galaxies: starburst ; infrared: galaxies ;
submillimeter: galaxies
Abstract:
Until recently, only a handful of dusty, star-forming galaxies (DSFGs)
were known at z>4, most of them significantly amplified by
gravitational lensing. Here, we have increased the number of such
DSFGs substantially, selecting galaxies from the uniquely wide 250,
350, and 500µm Herschel-ATLAS imaging survey on the basis of their
extremely red far-infrared colors and faint 350 and 500µm flux
densities, based on which, they are expected to be largely unlensed,
luminous, rare, and very distant. The addition of ground-based
continuum photometry at longer wavelengths from the James Clerk
Maxwell Telescope and the Atacama Pathfinder Experiment allows us to
identify the dust peak in their spectral energy distributions (SEDs),
with which we can better constrain their redshifts. We select the SED
templates that are best able to determine photometric redshifts using
a sample of 69 high-redshift, lensed DSFGs, then perform checks to
assess the impact of the CMB on our technique, and to quantify the
systematic uncertainty associated with our photometric redshifts,
σ=0.14(1+z), using a sample of 25 galaxies with spectroscopic
redshifts, each consistent with our color selection. For
Herschel-selected ultrared galaxies with typical colors of
S500/S250∼2.2 and S500/S350∼1.3 and flux densities,
S500∼50mJy, we determine a median redshift, zphot=3.66, an
interquartile redshift range, 3.30-4.27, with a median rest-frame
8-1000µm luminosity, LIR, of 1.3x1013L☉. A third of the
galaxies lie at z>4, suggesting a space density, ρz>4, of
∼6x10-7Mpc-3. Our sample contains the most luminous known
star-forming galaxies, and the most overdense cluster of starbursting
proto-ellipticals found to date.
Description:
We use images created for the H-ATLAS Data Release 1
(Valiante+ 2016, J/MNRAS/462/3146), covering three equatorial fields
with right ascensions of 9, 12, and 15hr, the so-called GAMA09,
GAMA12, and GAMA15 fields, each covering ∼54deg2; in the north, we
also have ∼170deg2 of areal coverage in the North Galactic Pole
(NGP) field; finally, in the south, we have ∼285deg2 in the South
Galactic Pole (SGP) field, making a total of ∼600deg2. The 250, 350,
and 500um Herschel/SPIRE maps exploited here have 6, 8, and 12" pixels
and point-spread functions (PSFs) with an azimuthally averaged FWHM of
17.8", 24.0", and 35.2", respectively.
Observations of 109 ultrared dusty star-forming galaxies (DSFGs) were
obtained using SCUBA-2 at 850um, scheduled flexibly during the period
2012-2013. The FWHM of the main beam is 13.0" at 850um before smoothing.
Images were also taken with the Large APEX bolometer camera (LABOCA)
mounted on the 12m Atacama Pathfinder EXperiment (APEX) telescope on
Llano Chajnantor at an altitude of 5100m in Chile. LABOCA contains an
array of 295 composite bolometers, operating at a central wavelength
of 870um with a FWHM resolution of 19.2".
File Summary:
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FileName Lrecl Records Explanations
--------------------------------------------------------------------------------
ReadMe 80 . This file
table1.dat 111 112 Targets and their properties
table2.dat 42 112 Targets and their photometric redshift properties
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See also:
J/MNRAS/380/199 : SCUBA Half-Degree Extragalactic Survey. III (Ivison+, 2007)
J/ApJ/707/1201 : LABOCA ECDFS Submillimeter Survey (LESS) (Weiss+, 2009)
J/ApJ/719/763 : Millimeter-wave sources in the SPT survey (Vieira+, 2010)
J/MNRAS/411/505 : Sub-mm observations in Extended Chandra DFS (Chapin+, 2011)
J/ApJ/788/125 : An ALMA survey of ECDFS submm galaxies (Simpson+, 2014)
J/MNRAS/462/1989 : HerMES Large Mode Survey catalogue (Asboth+, 2016)
J/MNRAS/462/3146 : Herschel-ATLAS DR1 (HATLAS) (Valiante+, 2016)
J/ApJS/236/30 : Herschel-ATLAS (H-ATLAS) DR2 (Maddox+, 2018)
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 6 A6 --- --- [HATLAS]
7- 22 A16 --- HATLAS HATLAS designation (HHMMSS.s+DDMMSS or
JHHMMSS.s+DDMMSS);
<H-ATLAS JHHMMSS.s+DDMMSS> in Simbad
24- 33 A10 --- ID Short name
36- 36 A1 --- f_ID [b] b: Targets observed with
both LABOCA and SCUBA-2
38- 38 I1 --- Band [1/3] Band flag (1)
40- 43 F4.1 mJy S250 [-7.8/61.6] Flux density at 250um
45- 47 F3.1 mJy e_S250 [4.7/9.4] Uncertainty in S250
49- 52 F4.1 mJy S350 [10.8/89.1] Flux density at 350um
54- 57 F4.1 mJy e_S350 [7.3/10.3] Uncertainty in S350
59- 63 F5.1 mJy S500 [28.4/117.7] Flux density at 500um
65- 68 F4.1 mJy e_S500 [7.5/11.6] Uncertainty in S500
70- 73 F4.1 mJy S850 [1.0/46.9] Peak flux density at 850um
75- 77 F3.1 mJy e_S850 [1.6/5.6] Uncertainty in S850
79- 83 F5.1 mJy S850-45 [-25.5/62.4] Flux density at 850um in 45"
aperture
85- 88 F4.1 mJy e_S850-45 [2.3/13] Uncertainty in S850-45
90- 94 F5.1 mJy S850-60 [-40.2/71.3] Flux density at 850um in 60"
aperture
96- 99 F4.1 mJy e_S850-60 [3/18.4] Uncertainty in S850-60
101-104 I4 yr Obs.Y [2012/2014] Year of the observation
106-107 I2 "month" Obs.M [1/12] Month of the observation
109-110 I2 d Obs.D [1/30]? Day of the observation (2)
111 A1 --- f_Obs [l] l: Targets observed with LABOCA (2)
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Note (1): Code as follows:
1 = source with 250um peaks greater than 3.2σ.
2 = source with peak significance more than 2.4σ in the
350um residual map.
3 = source with 2.0σ peak in the residual 500um map.
Note (2): Targets observed with LABOCA have dates in the format YYYY-MM, since
data were taken over a number of nights.
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Byte-by-byte Description of file: table2.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 10 A10 --- ID Short name
11 A1 --- f_ID [b] b: Targets observed with
both LABOCA and SCUBA-2
13- 16 F4.2 --- zph [2.7/6.5] Photometric redshift
18- 21 F4.2 --- E_zph [0.02/1] Upper uncertainty in zph
23- 26 F4.2 --- e_zph [0.1/0.9] Lower uncertainty in zph
28- 32 F5.2 [Lsun] logLFIR [12.7/13.8] Log far-IR luminosity
34- 37 F4.2 [Lsun] E_logLFIR [0/0.2] Upper uncertainty in logLFIR
39- 42 F4.2 [Lsun] e_logLFIR [0.04/0.3] Lower uncertainty in logLFIR
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History:
From electronic version of the journal
(End) Prepared by [AAS], Emmanuelle Perret [CDS] 26-Feb-2020