J/A+A/496/45 CO maps of three lensed submillimetre galaxies (Knudsen+, 2009)
New CO detections of lensed submillimetre galaxies in A2218:
Probing molecular gas in the LIRG regime at high redshift.
Knudsen K.K., Neri R., Kneib J.-P., van der Werf P.P.
<Astron. Astrophys. 496, 45 (2009)>
=2009A&A...496...45K 2009A&A...496...45K
ADC_Keywords: Galaxies, radio ; Millimetric/submm sources ; Radio lines;
Carbon monoxide
Keywords: galaxies: evolution - galaxies: high-redshift - galaxies: ISM -
galaxies: starburst
Abstract:
Submillimetre galaxies (SMGs) are distant, dusty galaxies undergoing
star formation at prodigious rates. Recently there has been major
progress in understanding the nature of the bright SMGs (i.e.
S850um>5mJy). The samples for the fainter SMGs are small and are
currently in a phase of being built up through identification studies.
We study the molecular gas content in the two SMGs, SMMJ163555 and
SMMJ163541, at redshifts z=1.034 and z=3.187 with unlensed
submillimetre fluxes of 0.4mJy and 6.0mJy. Both SMGs are
gravitationally lensed by the foreground cluster Abell 2218.
We used the IRAM Plateau de Bure Interferometer to obtain observations
at 3mm of the lines CO(2-1) for SMMJ163555 and CO(3-2) for SMMJ163541.
Additionally, we obtained CO(4-3) observations for the candidate
z=4.048 SMMJ163556 with an unlensed submillimetre flux of 2.7mJy.
Results: The CO(2-1) line was detected for SMMJ163555 at redshift
1.0313 with an integrated line intensity of 1.2±0.2Jy.km/s and a
line width of 410±120km/s. From this a gas mass of 1.6x109M☉
is derived and a star formation efficiency of 440L☉/M☉
estimated. The CO(3-2) line was detected for SMMJ163541 at redshift
3.1824, possibly with a second component at redshift 3.1883, with an
integrated line intensity of 1.0±0.1Jy.km/s and a line width of
280±50km/s. From this a gas mass of 2.2x1010M☉ is derived
and a star formation efficiency of 1000L☉/M☉ is estimated.
For SMMJ163556, the CO(4-3) is undetected within the redshift range
4.035-4.082 down to a sensitivity of 0.15Jy.km/s.
Description:
The calibrated IRAM PdBI CO observations of the three high redshift
SMGs, SMMJ163555, SMMJ163541, and SMMJ163556 are here available in
fits format. The spectra cubes are given in RA, Dec, and velocity. The
files are named according to the source.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
maps.dat 72 3 List of the maps
fits/* . 3 FITS maps
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Byte-by-byte Description of file: maps.dat
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Bytes Format Units Label Explanations
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1- 12 A12 --- FileName Name of the FITS file in subdirectory fits
14- 16 A3 --- --- [SMM]
17- 32 A16 --- SMM Source name (JHHMMSS.S+DDMMSS)
34- 35 A2 --- --- [z=]
36- 39 F4.2 --- z Source redshift
41- 72 A32 --- Title Title of map
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Acknowledgements:
Kirsten K. Knudsen, knudsen(at)astro.uni-bonn.de
(End) Kirsten K. Knudsen [Bonn, Germany], Patricia Vannier [CDS] 26-Jan-2009