J/ApJS/222/1 Faint ALMA 1.2mm sources down to ∼0.02mJy (Fujimoto+, 2016)
ALMA census of faint 1.2 mm sources down to ∼0.02 mJy: extragalactic background
light and dust-poor, high-z galaxies.
Fujimoto S., Ouchi M., Ono Y., Shibuya T., Ishigaki M., Nagai H., Momose R.
<Astrophys. J. Suppl. Ser., 222, 1 (2016)>
=2016ApJS..222....1F 2016ApJS..222....1F (SIMBAD/NED BibCode)
ADC_Keywords: Millimetric/submm sources ; Redshifts
Keywords: galaxies: evolution; galaxies: formation; galaxies: high-redshift
Abstract:
We present statistics of 133 faint 1.2mm continuum sources detected in
about 120 deep Atacama Large Millimeter/submillimeter Array (ALMA)
pointing data that include all the archival deep data available by
2015 June. We derive number counts of 1.2mm continuum sources down to
0.02mJy partly with the assistance of gravitational lensing, and find
that the total integrated 1.2mm flux of the securely identified
sources is 22.9-5.6+6.7Jy/deg2 which corresponds to 10425+31%
of the extragalactic background light (EBL) measured by Cosmic
Background Explorer observations. These results suggest that the major
1.2mm EBL contributors are sources with 0.02mJy, and that very faint
1.2mm sources with ≲0.02mJy contribute negligibly to the EBL with the
possible flattening and/or truncation of number counts in this very
faint flux regime. To understand the physical origin of our faint ALMA
sources, we measure the galaxy bias bg by the counts-in-cells
technique, and place a stringent upper limit of bg<3.5 that is not
similar to bg values of massive distant red galaxies and
submillimeter galaxies but comparable to those of UV-bright,
star-forming BzK galaxies (sBzKs) and Lyman break galaxies (LBGs).
Moreover, in the optical and near-infrared (NIR) deep fields, we
identify optical-NIR counterparts for 59% of our faint ALMA sources,
the majority of which have luminosities, colors, and the IRX-β
relation the same as sBzKs and LBGs. We thus conclude that about a
half of our faint ALMA sources are dust-poor, high-z galaxies as known
as sBzKs and LBGs in optical studies, and that these faint ALMA
sources are not miniature (U)LIRGs simply scaled down with the
infrared brightness.
Description:
We use 67 continuum maps obtained by ∼120 pointing of the ALMA cycle
0-2 observations in Band 6/7 that accomplish high sensitivities and
angular resolutions.
For the mapping mode definitions, there are maps targeting field
regions by single-pointing observations, referred to as "field" data,
4 and 62 out of which are taken from our programs and the ALMA
archive, respectively.
Two out of the four maps were taken in the ALMA cycle-0 Band 6
observations for the spectroscopically confirmed Lyα emitter
(LAE) at z=6.595 (Himiko) and an LAE at z=6.511 (NB921-N-79144). See
Ono et al. (2014ApJ...795....5O 2014ApJ...795....5O) for a summary of these observations.
We also utilize two maps of newly obtained (ALMA cycle 2) field data
of Bands 6 and 7 taken for spectroscopically confirmed LAEs at z=5.7
(NB816-S-61269) and at z=7.3 (NB101-S-2904). The NB816-S-61269
observations were carried out in the ALMA program of #2012.1.00602.S
(PI: R. Momose) on 2014 May 20, Jun 19, and July 7 with 43 12m
antennae array in the range of 18-650m baseline. The NB101-S-2904
data were taken in the ALMA program of #2012.1.00088.S (PI: M. Ouchi)
on 2014 July 22 and August 6, 7, 14, and 18, with 55 12m antennae
array in the extended configuration of 18-1300m baseline. See
section 2.1 for further explanations.
To increase the number of ALMA sources, we make full use of ALMA
archival data of cycles 0 and 1 that became public by 2015 June. See
references in table2 for the collected 62 maps and section 2.2.1 for
further details.
One-cluster data were taken for Abell 1689 (A1689) in ALMA cycle 0 and
1 observations (PI: J. Richard) of ALMA #2011.0.00319.S and
#2012.1.00261.S (see section 2.2.2 for further explanations).
File Summary:
--------------------------------------------------------------------------------
FileName Lrecl Records Explanations
--------------------------------------------------------------------------------
ReadMe 80 . This file
table2.dat 96 67 ALMA maps of this study
table3.dat 62 133 Source catalog
table10.dat 86 17 Properties of our optical-NIR counterparts
--------------------------------------------------------------------------------
See also:
VIII/95 : Herschel Multi-tiered Extragalactic Survey (Oliver+, 2012)
J/ApJ/803/34 : z∼4-10 galaxies from HST legacy fields (Bouwens+, 2015)
J/MNRAS/442/577 : ALESS submm galaxies radio properties (Thomson+, 2014)
J/ApJS/209/22 : SSDF survey: IRAC catalogs (Ashby+, 2013)
J/ApJ/768/91 : ALMA observations of LESS submm galaxies (Hodge+, 2013)
J/MNRAS/411/102 : AzTEC/ASTE 1.1mm observations in the ADF-S (Hatsukade+ 2011)
J/ApJ/723/1678 : LensPerfect A1689 analysis (Coe+, 2010)
J/MNRAS/401/160 : AzTEC survey of the SHADES fields. I. (Austermann+, 2010)
J/ApJ/707/1201 : LABOCA ECDFS Submillimeter Survey (LESS) (Weiss+, 2009)
J/ApJS/179/124 : Subaru/XMM-Newton deep survey (SXDS) III. (Ueda+, 2008)
J/ApJS/176/301 : Subaru/XMM-Newton deep survey IV. (SXDS) (Ouchi+, 2008)
J/MNRAS/384/1611 : Submm observations in gravitational lenses (Knudsen+, 2008)
J/ApJ/668/643 : Multiply imaged gravitational lens systems (Limousin+, 2007)
J/MNRAS/372/1621 : SCUBA Half-Degree Extragalactic Survey. II (Coppin+, 2006)
J/MNRAS/372/741 : SXDF 100µJy catalogue (Simpson+, 2006)
J/ApJ/622/772 : Redshift survey of submillimeter galaxies (Chapman+, 2005)
J/ApJ/592/728 : Lyman break galaxies at redshift z∼3 (Steidel+, 2003)
http://almascience.eso.org/alma-data/archive : ALMA archive access
Byte-by-byte Description of file: table2.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1 A1 --- Set Sub-dataset (1)
3- 4 I2 --- Map [1/67] Running sequence number
6- 25 A20 --- Target ALMA target name
27- 30 F4.2 nm lambda [1/1.4] Wavelength in the observed frame
32- 34 I3 GHz nu [216/291] Frequency in the observed frame
36 I1 --- Band [6/7] ALMA band
38- 41 F4.1 uJy/beam Sig [8.5/95.2] One sigma noise measured in each
map before primary beam correction
42 A1 --- --- [-]
43- 46 F4.1 uJy/beam Sig2 ? Second value of Sig for Cluster set
47 A1 --- f_Sig2 [a] a: Noise levels are measured in
the nine regions (see the text for details)
49- 52 F4.2 arcsec Beam1 [0.4/1.9] Beam size 1
53 A1 --- --- [x]
54- 57 F4.2 arcsec Beam2 [0.3/1.1] Beam size 2
59- 62 F4.2 --- S1.2/S [0.6/1.6] Ratio of the flux density
(S1.2mm/Sobs) (2)
64- 66 A3 --- Ref Reference(s) (3)
68- 81 A14 --- PID1 First project ID
83- 96 A14 --- PID2 Second project ID if any
--------------------------------------------------------------------------------
Note (1): Sub-dataset as follows:
A = Deep data; low (≤60uJy) noise level
B = Medium deep data; high (>60uJy) noise level
C = Cluster data (One map for a galaxy cluster taken by mapping observations
from the ALMA archive).
Note (2): Ratio of the flux density at 1.2mm, S1.2mm, to the one at the
observed wavelength, Sobs, that is estimated with the modified black
body spectrum of βd=1.8, a dust temperature of Td=35K, and
a redshift of z=2.5.
Note (3): Reference as follows:
a = Vanzella et al. (2011ApJ...730L..35V 2011ApJ...730L..35V)
b = Maiolino et al. (2015MNRAS.452...54M 2015MNRAS.452...54M)
c = Tanvir et al. (2012ApJ...754...46T 2012ApJ...754...46T)
d = Berger et al. (2014ApJ...796...96B 2014ApJ...796...96B)
e = Konno et al. (2014ApJ...797...16K 2014ApJ...797...16K)
f = Ouchi et al. (2010ApJ...723..869O 2010ApJ...723..869O)
g = Haberl et al. (1998AN....319...97H 1998AN....319...97H)
h = Ouchi et al. (2013ApJ...778..102O 2013ApJ...778..102O)
i = Ono et al. (2014ApJ...795....5O 2014ApJ...795....5O)
j = Iye et al. (2006Natur.443..186I 2006Natur.443..186I)
k = Ota et al. (2014ApJ...792...34O 2014ApJ...792...34O)
l = Zampieri et al. (2001A&A...378L...5Z 2001A&A...378L...5Z)
m = Willott et al. (2010AJ....139..906W 2010AJ....139..906W)
n = Willott et al. (2013ApJ...770...13W 2013ApJ...770...13W)
o = Ouchi et al. (2009ApJ...706.1136O 2009ApJ...706.1136O)
p = Hatsukade et al. (2014Natur.510..247H 2014Natur.510..247H)
q = Martin et al. (2006NewAR..50...53M 2006NewAR..50...53M)
r = Yabe et al. (2012PASJ...64...60Y 2012PASJ...64...60Y)
s = Hatsukade et al. (2013ApJ...769L..27H 2013ApJ...769L..27H)
t = Watson et al. (2015Natur.519..327W 2015Natur.519..327W)
--------------------------------------------------------------------------------
Byte-by-byte Description of file: table3.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 3 I3 --- Seq [1/133] Running sequence number
5 A1 --- f_Seq [a] Flag on Seq (1)
7- 8 I2 --- Map [1/67] Map identifier
10- 19 F10.6 deg RAdeg Right ascension in decimal degress (J2000)
21- 30 F10.6 deg DEdeg Declination in decimal degress (J2000)
32- 35 F4.2 mJy Sobs [0.05/1.1] Peak flux density (G1)
37- 40 F4.2 mJy e_Sobs [0.01/0.2] Sobs uncertainty
42- 45 F4.2 mJy S1.2c [0.002/1.17]? The best estimate source flux
density at 1.2mm (2)
47 A1 --- f_S1.2c [b] Flag on S1.2c (3)
49- 52 F4.2 mJy e_S1.2c [0.001/0.3]? S1.2c uncertainty
54- 57 F4.1 --- S/N [3.4/39.3] Signal-to-noise ratio of
the peak flux density
59- 62 F4.2 --- Fsp [0/0.8] Spurious source rate that is
defined by Equation 3 (ratio of negative to
positive peak numbers)
--------------------------------------------------------------------------------
Note (1):
a = Source identified in the Band 7 map.
Unless otherwise specified, the source is found in the Band 6 map.
Note (2): The source flux is estimated with the 2D Gaussian-fitting routine of
imfit in CASA (Section 3.4) with the primary beam correction and the
flux scaling to 1.2mm (Section 3). For the sources found in the
cluster data, the lensing magnification corrections are also applied
(Section 3.5). The lensing magnification factors are estimated at the
ALMA flux peak positions. The error bar includes the random noise, 10%
of ALMA system's flux measurement uncertainty, and the lensing
magnification uncertainty (Section 4.1).
Note (3): The lensing magnification is corrected.
The ID 124 source has 0.0020±0.0010mJy for the best estimate source
flux density at 1.2mm with the primary beam and lensing magnification
corrections.
--------------------------------------------------------------------------------
Byte-by-byte Description of file: table10.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 3 A3 --- ID Source identifier
5 A1 --- f_ID [bcd] Flag on ID (1)
7- 16 F10.6 deg RAdeg Right ascension in decimal degrees (J2000)
18- 26 F9.6 deg DEdeg Declination in decimal degrees (J2000)
28- 31 F4.2 mm lambda [1/1.4] Wavelength in the observed frame
33- 37 F5.3 mJy Sobs [0.04/0.6] Peak flux density (G1)
39- 43 F5.3 mJy e_Sobs [0.01/0.2] Sobs uncertainty
45- 49 F5.3 mJy S1.2c [0.02/0.6] The best estimate source flux
density at 1.2mm (2)
51- 55 F5.3 mJy e_S1.2c S1.2c uncertainty
56 A1 --- f_S1.2c [ae] Flag on S1.2c (1)
58- 61 F4.2 --- zph [0.6/1.6]? Photometric redshift estimated by
Williams et al. (2009ApJ...691.1879W 2009ApJ...691.1879W)
63- 66 F4.2 --- E_zph [0.01/0.3]? Positive error on zph
68- 71 F4.2 --- e_zph [0.02/0.03]? Negative error on zph
73- 76 F4.2 --- zsp [2.6]? Spectroscopic redshift obtained by
Limousin et al. (2007, J/ApJ/668/643)
78- 79 A2 --- sBzK [Y'N ] Meet the color selection criteria of sBzK?
81 A1 --- pBzK [N ] Meet the color selection criteria of pBzK?
83- 84 A2 --- BX/BM [Y'N ] Meet the color selection criteria of BX/BM?
86 A1 --- AGN [N ] Meet the color selection criteria of AGN?
--------------------------------------------------------------------------------
Note (1): Flag as follows:
a = The photometry of imfit may be biased due to the systematic noise. The
SExtractor peak flux measurement suggests 0.32±0.08mJy.
b = Same as the AS2 source in Hatsukade et al. (2015ApJ...810...91H 2015ApJ...810...91H).
c = Same as the AS4 source in Hatsukade et al. (2014Natur.510..247H 2014Natur.510..247H).
d = Same as the Chen-5 source in Chen et al. (2014ApJ...789...12C 2014ApJ...789...12C).
e = The magnification uncertainty (Section 3.5) is also included in the error.
Note (2): The source flux is estimated with the 2D Gaussian-fitting routine of
imfit in CASA (Section 3.4) with the primary beam correction and the
flux scaling to 1.2mm (Section 3). For A1 and A2 sources, the lensing
magnification corrections are also applied. The lensing magnification
factors are estimated at the ALMA flux peak positions of A1 and A2.
--------------------------------------------------------------------------------
Global notes:
Note (G1): Peak flux density of the SExtractor measurement (Section 3.1) with
the primary beam correction at the observed wavelength.
--------------------------------------------------------------------------------
History:
From electronic version of the journal
(End) Emmanuelle Perret [CDS] 17-Jun-2016