First Supra-THz Heterodyne Array Receivers for Astronomy With the SOFIA Observatory

Risacher, C.; Güsten, R.; Stützki, J.; Hübers, Heinz‐Wilhelm; Büchel, D.; Graf, U. U.; Heyminck, S.; Honingh, C. E.; Jacobs, K.; Klein, Bernd; Klein, Thomas; Leinz, C.; Pütz, P.; Reyes, Nicolás; Ricken, Oliver; Wunsch, Hans-Joachim; Fusco, P.; Rosner, S. J.

doi:10.1109/tthz.2015.2508005

Cited by 66 publications

(56 citation statements)

References 37 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…For the tuning to the [OI] 63 µm line, a quantum-cascade laser was used as local oscillator (Richter et al 2015). At the Cep E-mm position, the zerolevel width observed for example by Lefloch et al (2011) For OH and CO observations of all three positions, the lower frequency, L2 channel was connected to 4 GHz wide digital back-ends described in Risacher et al (2016), providing respective spectral resolutions of 1.00 and 0.99 km s −1 (given in Table 2). This channel was tuned in LSB to the frequency of the OH triplet between 2 Π 1/2 J = 3/2 and J = 1/2 at 1837.817 GHz.…”

Section: Observationsmentioning

confidence: 99%

Nature of shocks revealed by SOFIA OI observations in the Cepheus E protostellar outflow

Gusdorf

Anderl

Leflóch

et al. 2017

A&A

View full text Add to dashboard Cite

Context. Protostellar jets and outflows are key features of the star-formation process, and primary processes of the feedback of young stars on the interstellar medium. Understanding the underlying shocks is necessary to explain how jet and outflow systems are launched, and to quantify their chemical and energetic impacts on the surrounding medium. Aims. We performed a high-spectral resolution study of the [OI] 63 µm emission in the outflow of the intermediate-mass Class 0 protostar Cep E-mm. The goal is to determine the structure of the outflow, to constrain the chemical conditions in the various components, and to understand the nature of the underlying shocks, thus probing the origin of the mass-loss phenomenon.Methods. We present observations of the O i 3 P 1 → 3 P 2 , OH between 2 Π 1/2 J = 3/2 and J = 1/2 at 1837.8 GHz, and CO (16-15) lines with the GREAT receiver onboard SOFIA towards three positions in the Cep E protostellar outflow: Cep E-mm (the driving protostar), Cep E-BI (in the southern lobe), and Cep E-BII (the terminal position in the southern lobe). Results. The line is detected at all three positions. The [OI] 63 µm line is detected in Cep E-BI and BII, whereas the OH line is not detected. In Cep E-BII, we identify three kinematical components in O i and CO. These were already detected in CO transitions and relate to spatial components: the jet, the HH377 terminal bow-shock, and the outflow cavity. We measure line temperature and line integrated intensity ratios for all components. The O i column density is higher in the outflow cavity than in the jet, which itself is higher than in the terminal shock. The terminal shock is the region where the abundance ratio of O i to CO is the lowest (about 0.2), whereas the jet component is atomic (N(O i) / N(CO) ∼ 2.7). In the jet, we compare the [OI] 63 µm observations with shock models that successfully fit the integrated intensity of 10 CO lines. We find that these models most likely do not fit the [OI] 63 µm data.Conclusions. The high intensity of O i emission points towards the propagation of additional dissociative or alternative FUV-irradiated shocks, where the illumination comes from the shock itself. A picture emerges from the sample of low-to-high mass protostellar outflows, where similar observations have been performed, with the effects of illumination increasing with the mass of the protostar. These findings need confirmation with more observational constraints and a larger sample.

show abstract

Section: Observationsmentioning

confidence: 99%

Nature of shocks revealed by SOFIA OI observations in the Cepheus E protostellar outflow

Gusdorf

Anderl

Leflóch

et al. 2017

A&A

View full text Add to dashboard Cite

show abstract

“…3 Despite the apparent advantage over SIS, HEB mixers show an excellent noise performance in a rather limited IF band: the 3 dB noise bandwidth (NBW) of NbN HEB mixers (currently, the most frequently used HEB mixers) is not more than 4-5 GHz. [4][5][6] The IF range >5 GHz becomes unusable. The discussed limitation of NbN HEB mixers is determined by the limited HEB mixer gain bandwidth (GBW) caused by a finite electron energy relaxation rate.…”

mentioning

confidence: 99%

Low noise terahertz MgB2 hot-electron bolometer mixers with an 11 GHz bandwidth

Novoselov

Cherednichenko

2017

Applied Physics Letters

View full text Add to dashboard Cite

Terahertz (THz) hot-electron bolometer mixers reach a unique combination of low noise, wide noise bandwidth, and high operation temperature when 6 nm thick superconducting MgB2 films are used. We obtained a noise bandwidth of 11 GHz with a minimum receiver noise temperature of 930 K with a 1.63 THz Local Oscillator (LO), and a 5 K operation temperature. At 15 K and 20 K, the noise temperature is 1100 K and 1600 K, respectively. From 0.69 THz to 1.63 THz, the receiver noise increases by only 12%. Device current-voltage characteristics are identical when pumped with LOs from 0.69 THz up to 2.56 THz, and match well with IVs at elevated temperatures. Therefore, the effect of the THz waves on the mixer is totally thermal, due to absorption in the π conduction band of MgB2.

show abstract

“…This allows simultaneous measurements of the locations of up to 24 individual receiver beams, 21 of which are required for the upGREAT extension of our instrument [7]. The microcontroller communicates with a control computer through an ethernet interface.…”

Section: Technical Realizationmentioning

confidence: 99%