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To make best use of the exceptional good weather conditions at Chajnantor we developed CHAMP+, a two time seven pixel dual-color heterodyne array for operation in the 350 and 450 µm atmospheric windows. CHAMP+ uses state-of-the-art SIS-mixers provided by our collaborators at SRON. To maximize its performance, optical single sideband filter are implemented for each of the two subarrays, and most of the optics is operated cold (20K) to minimize noise contributions. The instrument can be operated remotely, under full computer control of all components. The autocorrelator backend, currently in operation with 2 × 1GHz of bandwidth for each of the 14 heterodyne channels, will be upgraded by a new technologies FFT spectrometer array in mid 2008. CHAMP+ has been commissioned successfully in late 2007. We will review the performance of the instrument "in the field," and present its characteristics as measured on-sky.
Based on our reconfigurable FPGA spectrometer technology, we have developed a read-out system, operating in the frequency domain, for arrays of Microwave Kinetic Inductance Detectors (MKIDs). The readout consists of a combination of two digital boards: A programmable DAC-/FPGA-board (tone-generator) to stimulate the MKIDs detectors and an ADC-/FPGA-unit to analyze the detectors response. Laboratory measurement show no deterioration of the noise performance compared to low noise analog mixing. Thus, this technique allows capturing several hundreds of detector signals with just one pair of coaxial cables.
Spectral surveys provide the only way to determine the full molecular inventory of an object and hence build a comprehensive view of the state of the molecular gas and its role in star formation and the structure and evolution of the ISM. Of course spectral surveys also provide the most efficient method of identifying new and unexpected species that have to be include in the chemical networks. The most extensive and complete survey of an extragalactic system has been the continuous spectral survey from 129 GHz to 175 GHz carried out by Martín et al. (2006) toward NGC253. This first spectral line surveys at 2 mm towards the prototypical starbursts galaxies NGC253 have shown an unexpected chemical richness.
We present a new multi-pixel high resolution (R ≳ 107) spectrometer for the Stratospheric Observatory for Far-Infrared Astronomy (SOFIA). The receiver uses 2 × 7-pixel subarrays in orthogonal polarization, each in an hexagonal array around a central pixel. We present the first results for this new instrument after commissioning campaigns in May and December 2015 and after science observations performed in May 2016. The receiver is designed to ultimately cover the full 1.8−2.5 THz frequency range but in its first implementation, the observing range was limited to observations of the [CII] line at 1.9 THz in 2015 and extended to 1.83−2.07 THz in 2016. The instrument sensitivities are state-of-the-art and the first scientific observations performed shortly after the commissioning confirm that the time efficiency for large scale imaging is improved by more than an order of magnitude as compared to single pixel receivers. An example of large scale mapping around the Horsehead Nebula is presented here illustrating this improvement. The array has been added to SOFIA’s instrument suite already for ongoing observing cycle 4.
GREAT, the German REceiver for Astronomy at THz frequencies, has successfully passed its pre-shipment acceptance review conducted by DLR and NASA on December 4-5, 2008. Shipment to DAOF/Palmdale, home of the SOFIA observatory, has been released; airworthiness was stated by NASA. Since, due to schedule slips on the SOFIA project level, first science flights with GREAT were delayed to mid 2010. Here we present GREAT’s short science flight configuration: two heterodyne channels will be operated simultaneously in the frequency ranges of 1.25-1.50 and 1.82-1.91 THz, respectively, driven by solid-state type local oscillator systems, and supported by a wide suite of back-ends. The receiver was extensively tested for about 6 month in the MPIfR labs, showing performances compliant with specifications. This short science configuration will be available to the interested SOFIA user communities in collaboration with the GREAT PI team during SOFIA’s upcoming Basic Science flights.
