J/MNRAS/384/1611 Submm observations in gravitational lenses (Knudsen+, 2008)
Probing the submillimetre number counts at f(850µm)<2mJy.
Knudsen K.K., Van Der Werf P.P., Kneib J.-P.
<Mon. Not. R. Astron. Soc., 384, 1611-1626 (2008)>
=2008MNRAS.384.1611K 2008MNRAS.384.1611K
ADC_Keywords: Clusters, galaxy ; Millimetric/submm sources ; Redshifts
Keywords: surveys - galaxies: evolution - galaxies: high-redshift -
galaxies: starburst - submillimetre
Abstract:
We have conducted a submillimetre mapping survey of faint,
gravitationally lensed sources, where we have targeted 12 galaxy
clusters and additionally the New Technology Telescope (NTT) Deep
Field. The total area surveyed is 71.5arcmin2 in the image plane;
correcting for gravitational lensing, the total area surveyed is
40arcmin2 in the source plane for a typical source redshift z≫2.5.
In the deepest maps, an image plane depth of 1σ rms ∼0.8mJy is
reached. This survey is the largest survey to date to reach such
depths. In total 59 sources were detected, including three multiply
imaged sources. The gravitational lensing makes it possible to detect
sources with flux density below the blank field confusion limit. The
lensing-corrected fluxes range from 0.11 to 19mJy. After correcting
for multiplicity, there are 10 sources with fluxes <2mJy of which
seven have submJy fluxes, doubling the number of such sources known.
Number counts are determined below the confusion limit. At 1mJy, the
integrated number count is ∼104deg-2, and at 0.5mJy it is
∼2x104deg-2. Based on the number counts, at a source plan flux
limit of 0.1mJy, essentially all of the 850-m background emission has
been resolved. The dominant contribution (>50 per cent) to the
integrated background arises from sources with fluxes S850 between 0.4
and 2.5mJy, while the bright sources S850>6mJy contribute only 10 per
cent.
File Summary:
--------------------------------------------------------------------------------
FileName Lrecl Records Explanations
--------------------------------------------------------------------------------
ReadMe 80 . This file
table1.dat 83 13 The observed fields
table3.dat 110 59 Catalogue of source positions, submm fluxes
and uncertainties
--------------------------------------------------------------------------------
Byte-by-byte Description of file: table1.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 15 A15 --- Cluster Cluster name
16 A1 --- n_Cluster [*] *: supplemented with data from the
JCMT archive
18- 19 I2 h RAh Right ascension (J2000)
21- 22 I2 min RAm Right ascension (J2000)
24- 27 F4.1 s RAs Right ascension (J2000)
29 A1 --- DE- Declination sign (J2000)
30- 31 I2 deg DEd Declination (J2000)
33- 34 I2 arcmin DEm Declination (J2000)
36- 39 F4.1 arcsec DEs Declination (J2000)
41- 46 F6.4 --- z ? Cluster redshift
48- 52 F5.2 h t850 Total integration time, but without overheads
54- 58 F5.2 h t450 Total integration time for 450um data
60- 63 F4.1 arcmin+2 W850 Area, given is the field covered after removing
the noisy edge at 850um
65- 68 F4.2 mJy N850 Lowest noise value in the whole 850um field (1)
70- 73 F4.2 mJy N850a Area-weighted noise level of the 850um field (1)
75- 78 F4.1 mJy N450 Lowest noise value in the whole 450um field (1)
80- 83 F4.1 mJy N450a Area-weighted noise level of the 450um field (1)
--------------------------------------------------------------------------------
Note (1): In mJy/beam
--------------------------------------------------------------------------------
Byte-by-byte Description of file: table3.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 15 A15 --- Cluster Cluster name
17- 19 A3 --- --- [SMM]
21- 36 A16 --- SMM SMM designation (JHHMMSS.s+DDMMSS)
37 A1 --- n_SMM [*] * for sources having P(Sj<0mJy)>5%
38- 41 F4.1 arcsec ePos rms uncertainty on position
43- 46 F4.1 mJy S850 Flux at 850um
48- 51 F4.1 --- S/N850 Signal-to-noise ratio of the detection
at 850um in flux units
53- 55 F3.1 mJy e_S850 rms uncertainty on S850um
57 A1 --- l_S450 Limit flag on S450um
58- 62 F5.1 mJy S450 ? Flux at 450um
64- 67 F4.1 --- S/N450 ? Signal-to-noise ratio of the detection
at 450um in flux units
69- 72 F4.1 mJy e_S450 ? rms uncertainty on S450um
74- 78 F5.3 --- z ? Redshift
80- 83 F4.1 --- mu ? Lensing magnification
85- 89 F5.2 --- muMC ? Lensing magnification from
Monte Carlo simulations
91- 96 F6.3 --- E_muMC ? Error on muMC (upper limit)
97-102 F6.3 --- e_muMC ? Error on muMC (lower limit)
103-106 F4.1 mJy S850D ? Deboost Flux at 850um
108-110 F3.1 mJy e_S850D ? rms uncertainty on S850umD
--------------------------------------------------------------------------------
History:
From electronic version of the journal
(End) Patricia Vannier [CDS] 10-Jul-2008