J/ApJ/749/65 H-ATLAS search for strongly lensed galaxies (Gonzalez-Nuevo+, 2012)
Herschel-ATLAS: toward a sample of ∼1000 strongly lensed galaxies.
Gonzalez-Nuevo J., Lapi A., Fleuren S., Bressan S., Danese L., De Zotti G.,
Negrello M., Cai Z.-Y., Fan L., Sutherland W., Baes M., Baker A.J.,
Clements D.L., Cooray A., Dannerbauer H., Dunne L., Dye S., Eales S.,
Frayer D.T., Harris A.I., Ivison R., Jarvis M.J., Michalowski M.J.,
Lopez-Caniego M., Rodighiero G., Rowlands K., Serjeant S., Scott D.,
van der Werf P., Auld R., Buttiglione S., Cava A., Dariush A., Fritz J.,
Hopwood R., Ibar E., Maddox S., Pascale E., Pohlen M., Rigby E., Smith D.,
Temi P.
<Astrophys. J., 749, 65 (2012)>
=2012ApJ...749...65G 2012ApJ...749...65G
ADC_Keywords: Galaxies, IR ; Photometry, SDSS ; Photometry, infrared ;
Redshifts ; Gravitational lensing ; Millimetric/submm sources
Keywords: galaxies: high-redshift - gravitational lensing: strong -
submillimeter: galaxies
Abstract:
While the selection of strongly lensed galaxies (SLGs) with 500µm
flux density S500>100mJy has proven to be rather straightforward,
for many applications it is important to analyze samples larger than
the ones obtained when confining ourselves to such a bright limit.
Moreover, only by probing to fainter flux densities is it possible to
exploit strong lensing to investigate the bulk of the high-z
star-forming galaxy population. We describe HALOS (the Herschel-ATLAS
Lensed Objects Selection), a method for efficiently selecting fainter
candidate SLGs, reaching a surface density of ≃1.5-2/deg2, i.e., a
factor of about 4-6 higher than that at the 100mJy flux limit. HALOS
will allow the selection of up to ∼1000 candidate SLGs (with
amplifications µ≳2) over the full H-ATLAS survey area. Applying
HALOS to the H-ATLAS Science Demonstration Phase field (≃14.4deg2)
we find 31 candidate SLGs, whose candidate lenses are identified in
the VIKING near-infrared catalog. Using the available information on
candidate sources and candidate lenses we tentatively estimate a ≃72%
purity of the sample. As expected, the purity decreases with
decreasing flux density of the sources and with increasing angular
separation between candidate sources and lenses. The redshift
distribution of the candidate lensed sources is close to that reported
for most previous surveys for lensed galaxies, while that of candidate
lenses extends to redshifts substantially higher than found in the
other surveys. The counts of candidate SLGs are also in good agreement
with model predictions. Even though a key ingredient of the method is
the deep near-infrared VIKING photometry, we show that H-ATLAS data
alone allow the selection of a similarly deep sample of candidate SLGs
with an efficiency close to 50%; a slightly lower surface density (≃
1.45/deg2) can be reached with a ∼70% efficiency.
Description:
64 galaxies from Herschel Astrophysical Terahertz Large Area Survey
(H-ATLAS; Eales et al. 2010PASP..122..499E 2010PASP..122..499E) with zphot,source≥1.2,
S350≥85mJy and S250≥35mJy are listed in Table 1. They constitute
our parent sample of very bright, high-redshift galaxies, among which
we will search for the candidate strongly lensed galaxies (SLGs).
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 95 64 The parent sample of lens candidates
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See also:
VIII/72 : CLASS survey of radio sources (Myers+, 2003)
J/ApJ/749/38 : CFHTLS-SL2S-ARCS strong lens candidates (More+, 2012)
J/ApJ/744/150 : Dust-obscured galaxies (DOGs) at z≃2 (Bussmann+, 2012)
J/MNRAS/421/3027 : Statisical study of galaxy dust emissions (Bourne+, 2012)
J/ApJ/719/763 : Millimeter-wave sources in the SPT survey (Vieira+, 2010)
J/ApJ/705/1099 : The Sloan Lens ACS (SLACS) Survey. IX. (Auger+, 2009)
J/ApJ/706/1364 : SINS survey of high-z galaxies (Forster Schreiber+, 2009)
J/ApJS/176/19 : COSMOS: strong lens systems (Faure+, 2008)
J/AJ/132/999 : SDSS quasar lens search (Oguri+, 2006)
J/ApJ/566/945 : Massive star forming regions at 1.2mm (Beuther+, 2002)
http://www.h-atlas.org/ : Herschel ATLAS home page
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 16 A16 --- H-ATLAS H-ATLAS designation (JHHMMSS.s+DDMMSS)
18 A1 --- f_H-ATLAS [*] *: strongly lensed galaxy (SLG) candidate
20- 22 I3 --- SDP [9/910] H-ATLAS Science Demonstration Phase
(SDP) field identification number
24- 26 A3 --- n_SDP [a-c,N ] Notes on candidates (1)
28- 30 I3 mJy S500 [44/249] Herschel/SPIRE 500um flux density
32- 33 I2 mJy e_S500 [9/10] S500 uncertainty
35- 37 I3 mJy S350 [85/403] Herschel/SPIRE 350um flux density
39 I1 mJy e_S350 [8] S350 uncertainty
41- 43 I3 mJy S250 [66/507] Herschel/SPIRE 250um flux density
45 I1 mJy e_S250 [7] S250 uncertainty
47- 50 F4.2 --- z [1.32/3.04] Redshift of the source
52- 55 F4.2 --- e_z [0.01/0.6] z uncertainty
57- 61 F5.2 W/Hz logL100 [26.77/27.6] Log of 100um luminosity (L100um)
63- 66 F4.2 W/Hz e_logL100 [0.27/0.45] logL100 uncertainty
68- 72 F5.2 --- zlens [-0.02/1.78]? Lens redshift
74- 77 F4.2 --- e_zlens [0.01/0.42]? zlens uncertainty
79- 80 A2 --- r_zlens [SVH ] Lens redshift origin (2)
82- 85 F4.2 --- (g-r) [0/3.32]? SDSS (g-r) color index
87- 90 F4.2 --- (Z-H) [0/2.35]? VIKING (Z-H) color index
92- 95 F4.2 arcsec Delta [0/9.43]? Angular separation between candidate
source and candidate lens (Δpos)
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Note (1): Flag as follows:
a = The optical counterpart has colors compatible with those of a late-type
galaxy.
b = Tentative lens probability <30%.
c = The optical counterpart is local, z<0.2.
N = Confirmed strongly lensed galaxy (Negrello et al. 2010Sci...330..800N 2010Sci...330..800N).
Note (2): Lens redshift origin as follows:
V = for VIKING (Fleuren et al. 2012MNRAS.423.2407F 2012MNRAS.423.2407F)
H = for H-ATLAS (this work),
VH = for galaxies whose redshifts were re-estimated by us because the VIKING
estimate has exceedingly large errors (z=1.83±1.25, 1.86±1.42,
1.56±1.35 for SDP.238, SDP.302, and SDP.476, respectively),
S = for spectroscopic measurements (Bonfield et al. 2011MNRAS.416...13B 2011MNRAS.416...13B,
Negrello et al. 2010Sci...330..800N 2010Sci...330..800N, Harris et al. (ApJ, submitted),
Cox et al. 2011ApJ...740...63C 2011ApJ...740...63C, and M. Massardi et al.
(2012, in preparation)).
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Nomenclature Notes:
Table 1: Objects are also <[GLF2012] SDP NNN lens> and
<[GLF2012] SDP NNN source> in Simbad.
History:
From electronic version of the journal
(End) Emmanuelle Perret [CDS] 12-Nov-2013