During our Herschel Lensing Survey (HLS) of massive galaxy clusters, we have discovered an exceptionally bright source behind the z = 0.22 cluster Abell 773, which appears to be a strongly lensed submillimeter galaxy (SMG) at z = 5.2429. This source is unusual compared to most other lensed sources discovered by Herschel so far, because of its higher submm flux (∼200 mJy at 500 μm) and its high redshift. The dominant lens is a foreground z = 0.63 galaxy, not the cluster itself. The source has a far-infrared (FIR) luminosity of L FIR = 1.1 × 10 14 /μ L , where μ is the magnification factor, likely ∼11. We report here the redshift identification through CO lines with the IRAM-30 m, and the analysis of the gas excitation, based on CO(7-6), CO(6-5), CO(5-4) detected at IRAM and the CO(2-1) at the EVLA. All lines decompose into a wide and strong red component, and a narrower and weaker blue component, 540 km s −1 apart. Assuming the ultraluminous galaxy (ULIRG) CO-to-H 2 conversion ratio, the H 2 mass is 5.8 × 10 11 /μ M , of which one third is in a cool component. From the C I( 3 P 2 − 3 P 1 ) line we derive a C I/H 2 number abundance of 6 × 10 −5 similar to that in other ULIRGs. The H 2 O p (2, 0, 2−1, 1, 1) line is strong only in the red velocity component, with an intensity ratio I(H 2 O)/I(CO) ∼ 0.5, suggesting a strong local FIR radiation field, possibly from an active nucleus (AGN) component. We detect the [NII]205 μm line for the first time at high-z. It shows comparable blue and red components, with a strikingly broad blue one, suggesting strong ionized gas flows.

We have observed 104 gravitationally-lensed quasars at z ∼ 1-4 with Herschel/SPIRE, the largest such sample ever studied. By targeting gravitational lenses, we probe intrinsic farinfrared (FIR) luminosities and star formation rates (SFRs) more typical of the population than the extremely luminous sources that are otherwise accessible. We detect 72 objects with Herschel/SPIRE and find 66 percent (69 sources) of the sample have spectral energy distributions (SEDs) characteristic of dust emission. For 53 objects with sufficiently constrained SEDs, we find a median effective dust temperature of 38 +12 −5 K. By applying the radio-infrared correlation, we find no evidence for an FIR excess which is consistent with star-formationheated dust. We derive a median magnification-corrected FIR luminosity of 3.6 +4.8 −2.4 × 10 11 L and median SFR of 120 +160 −80 M yr −1 for 94 quasars with redshifts. We find ∼ 10 percent of our sample have FIR properties similar to typical dusty star-forming galaxies at z ∼ 2-3 and a range of SFRs <20-10000 M yr −1 for our sample as a whole. These results are in line with current models of quasar evolution and suggests a coexistence of dust-obscured star formation and AGN activity is typical of most quasars. We do not find a statistically-significant difference in the FIR luminosities of quasars in our sample with a radio excess relative to the radio-infrared correlation. Synchrotron emission is found to dominate at FIR wavelengths for < 15 percent of those sources classified as powerful radio galaxies.

We present the detection of four rotational emission lines of water vapor, from energy levels E u /k = 101-454 K, in the gravitationally lensed z = 3.9 QSO host galaxy APM 08279+5255. While the lowest H 2 O lines are collisionally excited in clumps of warm, dense gas (density of hydrogen nuclei n H = (3.1 ± 1.2) × 10 6 cm −3 , gas temperature T g ∼ 105 ± 21 K), we find that the excitation of the higher lines is dominated by the intense local infrared radiation field. Since only collisionally excited emission contributes to gas cooling, we conclude that H 2 O is not a significant coolant of the warm molecular gas. Our excitation model requires the radiatively excited gas to be located in an extended region of high 100 μm opacity (τ 100 = 0.9 ± 0.2). Locally, such extended infraredopaque regions are found only in the nuclei of ultraluminous infrared galaxies. We propose a model where the infrared-opaque circumnuclear cloud, which is penetrated by the X-ray radiation field of the QSO nucleus, contains clumps of massive star formation where the H 2 O emission originates. The radiation pressure from the intense local infrared radiation field exceeds the thermal gas pressure by about an order of magnitude, suggesting close to Eddington-limited star formation in these clumps.

Using far-infrared imaging from the "Herschel Lensing Survey", we derive dust properties of spectroscopically-confirmed cluster member galaxies within two massive systems at z∼0.3: the merging Bullet Cluster and the more relaxed MS2137.3-2353. Most star-forming cluster sources (∼90%) have characteristic dust temperatures similar to local field galaxies of comparable infrared (IR) luminosity (T dust ∼ 30 K). Several sub-LIRG (L IR < 10 11 L ⊙ ) Bullet Cluster members are much warmer (T dust > 37 K) with far-infrared spectral energy distribution (SED) shapes resembling LIRG-type local templates. X-ray and mid-infrared data suggest that obscured active galactic nuclei do not contribute significantly to the infrared flux of these "warm dust" galaxies. Sources of comparable IR-luminosity and dust temperature are not observed in the relaxed cluster MS2137, although the significance is too low to speculate on an origin involving recent cluster merging. "Warm dust" galaxies are, however, statistically rarer in field samples (> 3 σ), indicating that the responsible mechanism may relate to the dense environment. The spatial distribution of these sources is similar to the whole far-infrared bright population, i.e. preferentially located in the cluster periphery, although the galaxy hosts tend towards lower stellar masses (M * < 10 10 M ⊙ ). We propose dust stripping and heating processes which could be responsible for the unusually warm characteristic dust temperatures. A normal star-forming galaxy would need 30-50% of its dust removed (preferentially stripped from the outer reaches, where dust is typically cooler) to recover a SED similar to a "warm dust" galaxy. These progenitors would not require a higher IR-luminosity or dust mass than the currently observed normal star-forming population.

The UltraViolet and infrared Sensors at high Quantum efficiency onboard a small SATellite (UVSQ-SAT) mission aims to demonstrate pioneering technologies for broadband measurement of the Earth’s radiation budget (ERB) and solar spectral irradiance (SSI) in the Herzberg continuum (200–242 nm) using high quantum efficiency ultraviolet and infrared sensors. This research and innovation mission has been initiated by the University of Versailles Saint-Quentin-en-Yvelines (UVSQ) with the support of the International Satellite Program in Research and Education (INSPIRE). The motivation of the UVSQ-SAT mission is to experiment miniaturized remote sensing sensors that could be used in the multi-point observation of Essential Climate Variables (ECV) by a small satellite constellation. UVSQ-SAT represents the first step in this ambitious satellite constellation project which is currently under development under the responsibility of the Laboratory Atmospheres, Environments, Space Observations (LATMOS), with the UVSQ-SAT CubeSat launch planned for 2020/2021. The UVSQ-SAT scientific payload consists of twelve miniaturized thermopile-based radiation sensors for monitoring incoming solar radiation and outgoing terrestrial radiation, four photodiodes that benefit from the intrinsic advantages of Ga 2 O 3 alloy-based sensors made by pulsed laser deposition for measuring solar UV spectral irradiance, and a new three-axis accelerometer/gyroscope/compass for satellite attitude estimation. We present here the scientific objectives of the UVSQ-SAT mission along the concepts and properties of the CubeSat platform and its payload. We also present the results of a numerical simulation study on the spatial reconstruction of the Earth’s radiation budget, on a geographical grid of 1 ° × 1 ° degree latitude-longitude, that could be achieved with UVSQ-SAT for different observation periods.

Context. Previous authors have reported the detection of intrinsically faint sub-mm emission lensed by the cluster MS0451.6−0305. They suggest that this emission arises from a merging system composed of a Ly-break galaxy and a pair of extremely red objects which are multiply-imaged in the optical/NIR observations. Aims. Since the submm emission presents an unusually large angular extent (∼1 ), the possible radio emission asociatted with that system can help to identify optical/NIR counterparts due to the higher spatial resolution and astrometric accuracy of the radio observations. Methods. Archive VLA data (BnA configuration at 1.4 GHz) was reduced and analysed. A simple lens model was constructed to aid the interpretation of the radio and pre-existing sub-mm and optical/NIR data.Results. We present a 1.4 GHz map of the central region of MS0451.6−0305 and report the detection of gravitationally lensed radio emission, coincident with the previously discovered sub-mm lensed emission. The overall morphology and scale of the radio and sub-mm emission are strikingly similar, extending ∼1 across the sky. This observation strongly suggests that the radio and sub-mm emission arise from the same sources. Preliminary estimates of the total S 850 µm /S 1.4 GHz flux density ratio appear to be consistent with that expected from distant star forming galaxies. The radio emission is resolved into 7 distinct components, and the overall structure can be explained, using a simple lens model, with three multiply-imaged radio sources at z ∼ 2.9. One of these sources is predicted to lie in the middle of the previously mentioned merging system in the source plane, suggesting that it is related to the intense star formation generated during the merging process.

Context. SMM J04542-0301 is an extended (∼1 ) submm source located near the core of the cluster MS0451.6-0305. It has been suggested that part of its emission arises from the interaction between a LBG and two EROs at z ∼ 2.9 that are multiply-imaged in the optical/NIR observations. However, the dramatic resolution difference between the sub-mm map and the optical/NIR images make it difficult to confirm this hypothesis. Aims. In a previous paper, we reported the detection of 1.4 GHz continuum radio emission coincident with this sub-mm source using VLA archival data. To fully understand the relation between this radio emission, the sub-mm emission, and the optical/IR multiplyimaged sources, we have re-observed the cluster with the VLA at higher resolution. Methods. The previous archival data has been re-reduced and combined with the new observations to produced a deep (∼10 μJy beam −1 ), high resolution (∼2 ) map centred on the cluster core. The strong lensing effect in the radio data has been quantified by constructing a new lens model of the cluster. Results. From the high resolution map we have robustly identified six radio sources located within SMM J 04542-0301. The brightest and most extended of these sources (RJ) is located in the middle of the sub-mm emission, and has no obvious counterpart in the optical/NIR. Three other detections (E1, E2 and E3) seem to be associated with the images of one of the EROs (B), although the NIR and radio emission appear to originate at slightly different positions in the source plane. The last two detections (CR1 and CR2), for which no optical/NIR counterpart have been found, seem to constitute two relatively compact emitting regions embedded in a ∼5 extended radio source located at the position of the sub-mm peak. The presence of this extended component (which contributes 38% of the total radio flux in this region) can only be explained if it is being produced by a lensed region of dust obscured star formation in the center of the merger. A comparison between the radio and sub-mm data at the same resolution suggests that E1, E2, E3, CR1 and CR2 are associated with the sub-mm emission. Conclusions. The radio observations presented in this paper provide strong observational evidence in favour of the merger hypothesis. However, the question if RJ is also contributing to the observed sub-mm emission remains open. These results illustrate the promising prospects for radio interferometry and strong gravitational lensing to study the internal structure of SMGs.

We predict the abundance of giant gravitational arcs produced by submillimeter galaxies (SMGs) lensed by foreground galaxy clusters, both at radio and submm wavelengths. The galaxy cluster population is modeled in a realistic way with the use of semi-analytic merger trees, while the density profiles of individual deflectors take into account ellipticity and substructures. The adopted typical size of the radio and submm emitting regions of SMGs is based on current radio/CO observations and the FIR-radio correlation. The source redshift distribution has been modeled using three different functions (based on spectroscopic/photometric redshift measurements and a simple evolutionary model) to quantify the effect of a high redshift tail on the number of arcs. The source number counts are compatible with currently available observations, and were suitably distorted to take into account the lensing magnification bias. We present tables and plots for the numbers of radio and submm arcs produced by SMGs as a function of surface brightness, useful for the planning of future surveys aimed at arc statistics studies. They show that e.g., the detection of several hundred submm arcs on the whole sky with a signal-to-noise ratio of at least 5 requires a sensitivity of 1 mJy arcsec −2 at 850 μm. Approximately the same number of radio arcs should be detected with the same signal-to-noise ratio with a surface brightness threshold of 20 μJy arcsec −2 at 1.4 GHz. Comparisons of these results with previous work found in the literature are also discussed.