Enhanced [CII] emission in a z=4.76 submillimetre galaxy

We present the detection of bright [CII] emission in the z=4.76 submillimetre galaxy LESS J033229.4-275619 using the Atacama Pathfinder EXperiment. This represents the highest redshift [CII] detection in a submm selected, star-formation dominated system. The AGN contributions to the [CII] and far-infrared (FIR) luminosities are small. We find an atomic mass derived from [CII] comparable to the molecular mass derived from CO. The ratio of the [CII], CO and FIR luminosities imply a radiation field strength G_0~10^3 and a density ~10^4 cm^-3 in a kpc-scale starburst, as seen in local and high redshift starbursts. The high L_[CII]/L_FIR=2.4x10^-3 and the very high L_[CII]/L_CO(1-0) ~ 10^4 are reminiscent of low metallicity dwarf galaxies, suggesting that the highest redshift star-forming galaxies may also be characterised by lower metallicities. We discuss the implications of a reduced metallicity on studies of the gas reservoirs, and conclude that especially at very high redshift, [CII] may be a more powerful and reliable tracer of the interstellar matter than CO.Comment: 5 pages, 2 figures; accepted for publication in Astronomy & Astrophysics Letter

New CO detections of lensed submillimeter galaxies in A2218: Probing molecular gas in the LIRG regime at high redshift

Context: Submillimeter 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. S(850um)>5mJy). The samples for the fainter SMGs are small and are currently in a phase of being built up through identification studies. Aims: We study the molecular gas content in two SMGs, SMMJ163555 and SMMJ163541, at z=1.034 and z=3.187 with unlensed submm fluxes of 0.4mJy and 6.0mJy. Both SMGs are gravitationally lensed by the foreground cluster A2218. Methods: IRAM Plateau de Bure Interferometry observations at 3mm were obtained for the lines CO(2-1) for SMMJ163555 and CO(3-2) for SMMJ163541. Additionally we obtained CO(4-3) for the candidate z=4.048 SMMJ163556 with an unlensed submm flux of 2.7mJy. Results: CO(2-1) was detected for SMMJ163555 at z=1.0313 with an integrated line intensity of 1.2+-0.2Jy km/s and a line width of 410+-120 km/s. From this a gas mass of 1.6x10^9 Msun is derived and a star formation efficiency of 440Lsun/Msun is estimated. CO(3-2) was detected for SMMJ163541 at z=3.1824, possibly with a second component at z=3.1883, with an integrated line intensity of 1.0+-0.1 Jy km/s and a line width of 280+-50 km/s. From this a gas mass of 2.2x10^10 Msun is derived and a star formation efficiency of 1000 Lsun/Msun is estimated. For SMMJ163556 the CO(4-3) is undetected within the redshift range 4.035-4.082 down to a sensitivity of 0.15 Jy km/s. Conclusions: Our CO line observations confirm the optical redshifts for SMMJ163555 and SMMJ163541. The CO line luminosity L'_CO for both galaxies is consistent with the L_FIR-L'_CO relation. SMMJ163555 has the lowest FIR luminosity of all SMGs with a known redshift and is one of the few high redshift LIRGs whose properties can be estimated prior to ALMA.Comment: 7 pages, 4 figures. A&A in pres

Submillimeter galaxies behind the Bullet Cluster (1E 0657-56)

Clusters of galaxies are effective gravitational lenses able to magnify background galaxies and making it possible to probe the fainter part of the galaxy population. Submillimeter galaxies, which are believed to be star-forming galaxies at typical redshifts of 2 to 3, are a major contaminant to the extended Sunyaev-Zeldovich (SZ) signal of galaxy clusters. For a proper quantification of the SZ signal the contribution of submillimeter galaxies needs to be quantified. The aims of this study are to identify submillimeter sources in the field of the Bullet Cluster (1E 0657-56), a massive cluster of galaxies at z~0.3, measure their flux densities at 870 micron, and search for counterparts at other wavelengths to constrain their properties. We carried out deep observations of the submillimeter continuum emission at 870 micron using the Large APEX BOlometer CAmera (LABOCA) on the Atacama Pathfinder EXperiment (APEX) telescope. Several numerical techniques were used to quantify the noise properties of the data and extract sources. In total, seventeen sources were found. Thirteen of them lie in the central 10 arcminutes of the map, which has a pixel sensitivity of 1.2 mJy per 22 arcsec beam. After correction for flux boosting and gravitational lensing, the number counts are consistent with published submm measurements. Nine of the sources have infrared counterparts in Spitzer maps. The strongest submm detection coincides with a source previously reported at other wavelengths, at an estimated redshift z~2.7. If the submm flux arises from two images of a galaxy magnified by a total factor of 75, as models have suggested, its intrinsic flux would be around 0.6 mJy, consistent with an intrinsic luminosity below 10^12 L_sun.Comment: Accepted by A&A, 15 pages, 11 figure

ALMA reveals a chemically evolved submillimeter galaxy at z=4.76

The chemical properties of high-z galaxies provide important information to constrain galaxy evolutionary scenarios. However, widely-used metallicity diagnostics based on rest-frame optical emission lines are not usable for heavily dust-enshrouded galaxies (such as Sub-Millimeter Galaxies; SMGs), especially at z>3. Here we focus on the flux ratio of the far-infrared fine-structure emission lines [NII]205um and [CII]158um to assess the metallicity of high-z SMGs. Through ALMA cycle 0 observations, we have detected the [NII]205um emission in a strongly [CII]-emitting SMG, LESS J033229.4-275619 at z=4.76. The velocity-integrated [NII]/[CII] flux ratio is 0.043 +/- 0.008. This is the first measurement of the [NII]/[CII] flux ratio in high-z galaxies, and the inferred flux ratio is similar to the ratio observed in the nearby universe (~0.02-0.07). The velocity-integrated flux ratio and photoionization models suggest that the metallicity in this SMG is consistent with solar, implying the chemical evolution has progressed very rapidly in this system at z=4.76. We also obtain a tight upper limit on the CO(12-11) transition, which translates into CO(12-11)/CO(2-1) <3.8 (3 sigma). This suggests that the molecular gas clouds in LESS J033229.4-275619 are not affected significantly by the radiation field emitted by the AGN in this system.Comment: 5 pages, 3 figures, accepted for publication in Astronomy and Astrophysics Letter

The link between SCUBA and Spitzer: cold galaxies at z lt 1

We show that the far-IR properties of distant Luminous and UltraLuminous InfraRed Galaxies (LIRGs and ULIRGs, respectively) are on average divergent from analogous sources in the local Universe. Our analysis is based on Spitzer Multiband Imaging Photometer (MIPS) and Infrared Array Camera (IRAC) data of LIR > 1010 L⊙, 70 μm selected objects in the 0.1 1 SubMillimetre Galaxies (SMGs) discovered in blank-field submillimetre surveys. The Herschel Space Observatory is well placed to fully characterize the nature of these objects, as its coverage extends over a major part of the far-IR/sub-mm SED for a wide redshift range

The faint counterparts of MAMBO mm sources near the NTT Deep Field

We discuss identifications for 18 sources from our MAMBO 1.2mm survey of the region surrounding the NTT Deep Field. We have obtained accurate positions from Very Large Array 1.4GHz interferometry and in a few cases IRAM mm interferometry, and have also made deep BVRIzJK imaging at ESO. We find thirteen 1.2mm sources associated with optical/near-infrared objects in the magnitude range K=19.0 to 22.5, while five are blank fields at K>22. The median redshift of the radio-identified mm sources is ~2.6 from the radio/mm estimator, and the median optical/near-infrared photometric redshifts for the objects with counterparts ~2.1. This suggests that those radio-identified mm sources without optical/near-infrared counterparts tend to lie at higher redshifts than those with optical/near-infrared counterparts. Compared to published identifications of objects from 850micron surveys of similar depth, the median K and I magnitudes of our counterparts are roughly two magnitudes fainter and the dispersion of I-K colors is less. Real differences in the median redshifts, residual mis-identifications with bright objects, cosmic variance, and small number statistics are likely to contribute to this significant difference, which also affects redshift measurement strategies. We discuss basic properties of the near-infrared/(sub)mm/radio spectral energy distributions of our galaxies and of interferometrically identified submm sources from the literature. From a comparison with submm objects with CO-confirmed spectroscopic redshifts we argue that roughly two thirds of the (sub)mm galaxies are at z>~2.5. This fraction is probably larger when including sources without radio counterparts. (abridged)Comment: 45 pages, 9 figures. Accepted by ApJ. The resolution of figures 2 and 3 has been degraded. A higher quality pdf version of this paper is available at http://www.mpe.mpg.de/~dannerb

A Retrospective Study To Determine Patients' Satisfaction With Fixed Dental Prostheses Provided During The Period 2008 – 2012 at The School of Dentistry In Trinidad

Introduction : The School of Dentistry undertakes the training of dental students, where they provide fixed dental prostheses such as crowns bridges and onlays to patients of the dental polyclinic. The aim of this study was to determine the patient satisfaction with their fixed prostheses and the quantity of remakes at the School of Dentistry polyclinic during the period 2008-2012. Methods : The lab records of fixed prosthetic work during the period 2008-2012 were analyzed. Patients who received treatment during this period were contacted via telephone for a structured interview via a questionnaire. Results : Ninety-six (96) patients were contacted via telephone and 72% of patients were female. Fifty-six (56) crowns and onlays, 22 conventional bridges and 18 resin-retained bridges were provided for patients. Ninety-six (96%) of patients were satisfied with the aesthetics (appearance) of their prosthesis immediately after fitting and 90.7 % were still satisfied with the appearance at the time of interview. 79.2% of prostheses were still in place at the time of interview but patients reported that 18% of crowns failed, 22.7% of conventional bridges and 27.8% of resin-retained bridges had failed. Fifteen (15%) of the fixed prostheses were remade. However, the majority of patients (99 %) were overall satisfied with their services at the School of Dentistry in Trinidad. Conclusion : Patients are generally satisfied with the fixed prosthetic work delivered at the School of Dentistry polyclinic and highly satisfied with the services provided. The amount of remakes whilst small can be reduced with more stringent quality assurance measure