ALMA Band 5 receiver cartridge. Design, performance, and commissioning

We describe the design, performance, and commissioning results for the new ALMA Band 5 receiver channel, 163–211 GHz, which is in the final stage of full deployment and expected to be available for observations in 2018. This manuscript provides the description of the new ALMA Band 5 receiver cartridge and serves as a reference for observers using the ALMA Band 5 receiver for observations. At the time of writing this paper, the ALMA Band 5 Production Consortium consisting of NOVA Instrumentation group, based in Groningen, NL, and GARD in Sweden have produced and delivered to ALMA Observatory over 60 receiver cartridges. All 60 cartridges fulfil the new more stringent specifications for Band 5 and demonstrate excellent noise temperatures, typically below 45 K single sideband (SSB) at 4 K detector physical temperature and below 35 K SSB at 3.5 K (typical for operation at the ALMA Frontend), providing the average sideband rejection better than 15 dB, and the integrated cross-polarization level better than –25 dB. The 70 warm cartridge assemblies, hosting Band 5 local oscillator and DC bias electronics, have been produced and delivered to ALMA by NRAO. The commissioning results confirm the excellent performance of the receivers

Multivariate genome-wide analysis of stress-related quantitative phenotypes

Exposure to traumatic stress increases the odds of developing a broad range of psychiatric conditions. Genetic studies targeting multiple stress-related quantitative phenotypes may shed light on mechanisms underlying vulnerability to psychopathology in the aftermath of stressful events. We applied a multivariate genome-wide association study (GWAS) to a unique military cohort (N = 583) in which we measured biochemical and behavioral phenotypes. The availability of pre- and post-deployment measurements allowed to capture changes in these phenotypes in response to stress. For genome-wide significant loci, we performed functional annotation, phenome-wide analysis and quasi-replication in PTSD case-control GWASs. We discovered one genetic variant reaching genome-wide significant association, surviving permutation and sensitivity analyses (rs10100651, p = 9.9 × 10−9). Functional annotation prioritized the genes INTS8 and TP53INP1. A phenome-wide scan revealed a significant association of these same genes with sleeping problems, hypertension and subjective well-being. Finally, a targeted lookup revealed nominally significant association of rs10100651 in a PTSD case-control GWAS in the UK Biobank (p = 0.02). We provide comprehensive evidence from multiple resources hinting at a role of the highlighted genetic variant in the human stress response, marking the power of multivariate genome-wide analysis of quantitative measures in stress research. Future genetic and functional studies can target this locus to further assess its effects on stress mediation and its possible role in psychopathology or resilience

APEX-SEPIA660 Early Science: gas at densities above 10

Context. The star-formation rates and stellar densities found in young massive clusters suggest that these stellar systems originate from gas at densities of n(H2) > 106 cm−3. Until today, however, the physical characterization of this ultra high density material remains largely unconstrained in observations. Aims. We investigate the density properties of the star-forming gas in the OMC-1 region located in the vicinity of the Orion Nebula Cluster (ONC). Methods. We mapped the molecular emission at 652 GHz in OMC-1 as part of the APEX-SEPIA660 Early Science. Results. We detect bright and extended N2H+ (J = 7–6) line emission along the entire OMC-1 region. Comparisons with previous ALMA data of the (J = 1–0) transition and radiative transfer models indicate that the line intensities observed in this N2H+ (7–6) line are produced by large mass reservoirs of gas at densities n(H2) > 107 cm−3. Conclusions. The first detection of this N2H+ (7–6) line at parsec-scales demonstrates the extreme density conditions of the star-forming gas in young massive clusters such as the ONC. Our results highlight the unique combination of sensitivity and mapping capabilities of the new SEPIA660 receiver for the study of the ISM properties at high frequencies

Performance of SIS mixers for upgrade of CHAMP+ 7-pixel arrays

We present here the performance of SIS mixers for upgrade of CHAMP+ array instrument on APEX telescope. In total it includes 14 mixers: 7 for the low band (600-720 GHz) and 7 for the high band (790-950 GHz). The mixers are a replacement for the existing set, which was commissioned on APEX in 2006. The low band mixers are based on Nb/AlN/Nb single tunneling SIS junction and high band ones -on Nb/AlN/NbN SIS twin junctions. The corrected DSB noise temperature of the low band mixers is roughly between 60 K and 120 K for the entire frequency range, and the corrected DSB noise temperature of the high band mixers varies from about 200 K at low frequencies to 400 K at the high end

Performance of SIS mixers for upgrade of CHAMP+ 7-pixel arrays

We present here the performance of SIS mixers for upgrade of CHAMP+ array instrument on APEX telescope. In total it includes 14 mixers: 7 for the low band (600-720 GHz) and 7 for the high band (790-950 GHz). The mixers are a replacement for the existing set, which was commissioned on APEX in 2006. The low band mixers are based on Nb/AlN/Nb single tunneling SIS junction and high band ones -on Nb/AlN/NbN SIS twin junctions. The corrected DSB noise temperature of the low band mixers is roughly between 60 K and 120 K for the entire frequency range, and the corrected DSB noise temperature of the high band mixers varies from about 200 K at low frequencies to 400 K at the high end

ALMA Band 9 cartridge

The Atacama Large Millimeter Array (ALMA) is a collaboration between Europe, North America, and Japan to build an aperture synthesis telescope with more than 50 12-m antennas at 5000 m altitude in Chile. In its full configuration, ALMA will observe in 10 bands between 30 and 950 GHz, and will provide astronomers with unprecedented sensitivity and spatial resolution at millimetre and sub-millimetre wavelengths. Band 9, covering 602-720 GHz, is the highest frequency band in the baseline ALMA project, and will thus offer the telescope's highest spatial resolutions. This paper describes the design of the Band 9 receiver cartridges for the Atacama Large Millimeter Array (ALMA). These are field-replaceable heterodyne front-ends offering high sensitivity, 602-720 GHz frequency coverage, 4-12 GHz IF bandwidth, and high quasioptical efficiencies. Because the project will ultimately require up to 64 cartridges to fully populate the ALMA array, two key aspects of the design of the Band 9 cartridge have been to take advantage of commercial manufacturing capabilities and to simplify the assembly of the cartridge

SEPIA - a new single pixel receiver at the APEX telescope

Context. We describe the new Swedish-ESO PI Instrument for APEX (SEPIA) receiver, which was designed and built by the Group for Advanced Receiver Development (GARD), at Onsala Space Observatory (OSO) in collaboration with ESO. It was installed and commissioned at the APEX telescope during 2015 with an ALMA Band 5 receiver channel and updated with a new frequency channel (ALMA Band 9) in February 2016. Aims. This manuscript aims to provide, for observers who use the SEPIA receiver, a reference in terms of the hardware description, optics and performance as well as the commissioning results. Methods. Out of three available receiver cartridge positions in SEPIA, the two current frequency channels, corresponding to ALMA Band 5, the RF band 158-211 GHz, and Band 9, the RF band 600-722 GHz, provide state-of-the-art dual polarization receivers. The Band 5 frequency channel uses 2SB SIS mixers with an average SSB noise temperature around 45K with IF (intermediate frequency) band 4-8 GHz for each sideband providing total 4 x 4 GHz IF band. The Band 9 frequency channel uses DSB SIS mixers with a noise temperature of 75-125 K with IF band 4-12 GHz for each polarization. Results. Both current SEPIA receiver channels are available to all APEX observers

BlackGEM: the wide-field multi-band optical telescope array

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