C. Risacher
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View article: Latest Advances in THz Heterodyne Receivers for Space Probes
Latest Advances in THz Heterodyne Receivers for Space Probes Open
View article: SOFIA-upGREAT Imaging Spectroscopy of the [C ii] 158 μm Fine-structure Line of the Sgr B Region in the Galactic Center
SOFIA-upGREAT Imaging Spectroscopy of the [C ii] 158 μm Fine-structure Line of the Sgr B Region in the Galactic Center Open
We report SOFIA-upGREAT spectroscopic imaging of the [C ii ] 158 μ m spectral line, as well as a number of [O i ] 63 μ m spectra, across a 67 × 45 pc field toward the Sgr B region in our Galactic center. The fully sampled and velocity-reso…
View article: Heterodyne Array Receivers for Space and Ground Based Applications
Heterodyne Array Receivers for Space and Ground Based Applications Open
The first heterodyne array receivers have been successfully built for ground-based telescopes and airborne observatories. In the talk we give a very quick overview of some prior heterodyne arrays. In particular, we will look at the innovat…
View article: SOFIA-upGREAT imaging spectroscopy of the [C II] 158um fine structure line of the Sgr B region in the Galactic center
SOFIA-upGREAT imaging spectroscopy of the [C II] 158um fine structure line of the Sgr B region in the Galactic center Open
We report SOFIA-upGREAT spectroscopic imaging of the [C II] 158um spectral line, as well as a number of [O I] 63um spectra, across a 67x45 pc field toward the Sgr B region in our Galactic center. The fully-sampled and velocity-resolved [C …
View article: Heterodyne Receiver for Origins
Heterodyne Receiver for Origins Open
The Heterodyne Receiver for Origins (HERO) is the first detailed study of a heterodyne focal plane array receiver for space applications. HERO gives the Origins Space Telescope the capability to observe at very high spectral resolution (R …
View article: An Era Comes to an End: The Legacy of LABOCA at APEX
An Era Comes to an End: The Legacy of LABOCA at APEX Open
It was 13 years ago, in May 2007, when the Large APEX Bolometer Camera (LABOCA) was commissioned as a facility instrument on the APEX telescope at the 5100-m-high Llano de Chajnantor. This 870-µm bolometer camera, in combination with the h…
View article: Far-Infrared Heterodyne Array Receivers
Far-Infrared Heterodyne Array Receivers Open
Astro 2020 Decadal Survey APC White paper
View article: Receiver development for the IRAM telescopes
Receiver development for the IRAM telescopes Open
IRAM operates several millimeter telescopes from two sites. The NOEMA interferometer located in the French Alps at 2500m with currently 10 antennas of 15m diameter and the 30m telescope in southern Spain, Pico Veleta (3000m), observe in th…
View article: Astrophysical detection of the helium hydride ion HeH+
Astrophysical detection of the helium hydride ion HeH+ Open
View article: Disruption of the Orion molecular core 1 by wind from the massive star θ1 Orionis C
Disruption of the Orion molecular core 1 by wind from the massive star θ1 Orionis C Open
View article: The upGREAT Dual Frequency Heterodyne Arrays for SOFIA
The upGREAT Dual Frequency Heterodyne Arrays for SOFIA Open
We present the performance of the upGREAT heterodyne array receivers on the SOFIA telescope after several years of operations. This instrument is a multi-pixel high resolution ([Formula: see text]) spectrometer for the Stratospheric Observ…
View article: A Proposed Heterodyne Receiver for the Origins Space Telescope
A Proposed Heterodyne Receiver for the Origins Space Telescope Open
The HEterodyne Receiver for the Origins Space Telescope (HERO) is a proposed design for a heterodyne focal plane array for a large space mission. The Origins Space Telescope (OST) is one of the four missions selected to be studied by NASA …
View article: Heterodyn receiver for the Origins Space Telescope concept 2
Heterodyn receiver for the Origins Space Telescope concept 2 Open
The Origins Space Telescope (OST) is a NASA study for a large satellite mission to be submitted to the 2020 Decadal Review. The proposed satellite has a fleet of instruments including the HEterodyne Receivers for OST (HERO). HERO is design…
View article: Velocity-resolved [ ] Emission from Cold Diffuse Clouds in the Interstellar Medium
Velocity-resolved [ ] Emission from Cold Diffuse Clouds in the Interstellar Medium Open
We have combined emission from the 158 μ m fine structure transition of C + observed with the GREAT and upGREAT instruments on SOFIA with 21 cm absorption spectra and visual extinction to characterize the diffuse interstellar clouds found …
View article: SOFIA/GREAT [C ii] observations in nearby clouds near the lines of sight towards B0355+508 and B0212+735
SOFIA/GREAT [C ii] observations in nearby clouds near the lines of sight towards B0355+508 and B0212+735 Open
We present SOFIA/GREAT [C ii] 2P3/2 →2P1/2 (1.9005369 THz) observations of nearby clouds near the lines of sight towards the quasars B0355+508 and B0212+735. These clouds have previously been identified as warm non-LTE diffuse clouds with …
View article: The upGREAT 1.9 THz multi-pixel high resolution spectrometer for the SOFIA Observatory
The upGREAT 1.9 THz multi-pixel high resolution spectrometer for the SOFIA Observatory Open
We present a new multi-pixel high resolution (R greater than or similar to 10(7)) spectrometer for the Stratospheric Observatory for Far-Infrared Astronomy (SOFIA). The receiver uses 2 x 7-pixel subarrays in orthogonal polarization, each i…
View article: Observations and modelling of CO and [C i] in protoplanetary disks. First detections of [C i] and constraints on the carbon abundance
Observations and modelling of CO and [C i] in protoplanetary disks. First detections of [C i] and constraints on the carbon abundance Open
Context. The gas-solid budget of carbon in protoplanetary disks is related to the composition of the cores and atmospheres of the planets forming in them. The key gas-phase carbon carriers CO, C0 and C+ can now be observed regularly in dis…
View article: Carbon gas in SMC low-metallicity star-forming regions
Carbon gas in SMC low-metallicity star-forming regions Open
This paper presents [CII], [CI] and CO emission line maps of the star-forming\nregions N66, N25+N26, and N88 in the metal-poor Local Group dwarf galaxy SMC.\nThe spatial and velocity structure of the large HII region N66 reveals an\nexpand…
View article: Observations and modelling of CO and [C i] in protoplanetary disks
Observations and modelling of CO and [C i] in protoplanetary disks Open
The gas-solid budget of carbon in protoplanetary disks is related to the\ncomposition of the cores and atmospheres of the planets forming in them. The\nkey gas-phase carbon carriers CO, C$^{0}$ and C$^{+}$ can now be observed in\ndisks. Th…
View article: Observations and modelling of CO and [CI] in disks. First detections of [CI] and constraints on the carbon abundance
Observations and modelling of CO and [CI] in disks. First detections of [CI] and constraints on the carbon abundance Open
The gas-solid budget of carbon in protoplanetary disks is related to the composition of the cores and atmospheres of the planets forming in them. The key gas-phase carbon carriers CO, C$^{0}$ and C$^{+}$ can now be observed in disks. The g…
View article: First Supra-THz Heterodyne Array Receivers for Astronomy With the SOFIA Observatory
First Supra-THz Heterodyne Array Receivers for Astronomy With the SOFIA Observatory Open
We present the upGREAT THz heterodyne arrays for far-infrared astronomy. The\nLow Frequency Array (LFA) is designed to cover the 1.9-2.5 THz range using\n2x7-pixel waveguide-based HEB mixer arrays in a dual polarization\nconfiguration. The…
View article: The structure of the Cepheus E protostellar outflow: The jet, the bowshock, and the cavity
The structure of the Cepheus E protostellar outflow: The jet, the bowshock, and the cavity Open
The freezeout of gas-phase species onto cold dust grains can drastically\nalter the chemistry and the heating-cooling balance of protostellar material.\nIn contrast to well-known species such as carbon monoxide (CO), the freezeout\nof vari…
View article: APEX-CHAMP<sup>+</sup>high-<i>J</i>CO observations of low-mass young stellar objects
APEX-CHAMP<sup>+</sup>high-<i>J</i>CO observations of low-mass young stellar objects Open
During the embedded stage of star formation, bipolar molecular outflows and\nUV radiation from the protostar are important feedback processes. Our aim is to\nquantify the feedback, mechanical and radiative, for a large sample of low-mass\n…
View article: APEX-CHAMP+ high-J CO observations of low-mass young stellar objects: IV. Mechanical and radiative feedback
APEX-CHAMP+ high-J CO observations of low-mass young stellar objects: IV. Mechanical and radiative feedback Open
During the embedded stage of star formation, bipolar molecular outflows and UV radiation from the protostar are important feedback processes. Our aim is to quantify the feedback, mechanical and radiative, for a large sample of low-mass sou…