U
Urs U. Graf
Researcher at University of Cologne
Publications - 144
Citations - 3630
Urs U. Graf is an academic researcher from University of Cologne. The author has contributed to research in topics: Heterodyne & Star formation. The author has an hindex of 33, co-authored 140 publications receiving 3337 citations. Previous affiliations of Urs U. Graf include Max Planck Society & University of Texas at Austin.
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Journal ArticleDOI
GREAT: the SOFIA high-frequency heterodyne instrument
Stefan Heyminck,Urs U. Graf,Rolf Güsten,Jürgen Stutzki,Heinz-Wilhelm Hübers,Heinz-Wilhelm Hübers,Paul Hartogh +6 more
TL;DR: The German REceiver for Astronomy at Terahertz frequencies (GREAT) is a dual-color heterodyne instrument for high-resolution far-infrared (FIR) spectroscopy as mentioned in this paper.
Journal ArticleDOI
GREAT/SOFIA atmospheric calibration
X. Guan,Jürgen Stutzki,Urs U. Graf,Rolf Güsten,Yoko Okada,M. A. Requena-Torres,R. Simon,Helmut Wiesemeyer +7 more
TL;DR: In this article, the authors compare the observed atmospheric emission with atmospheric model predictions, and discuss the problems identified in this comparison with respect to the observed data and the models, and describe the strategy used to calibrate the science data from GREAT/SOFIA during the first observing periods.
Journal ArticleDOI
GREAT/SOFIA atmospheric calibration
X. Guan,Jürgen Stutzki,Urs U. Graf,Rolf Güsten,Yoko Okada,Miguel Angel Requena Torres,R. Simon,Helmut Wiesemeyer +7 more
TL;DR: In this article, the authors compare the observed atmospheric emission with atmospheric model predictions, and discusse the problems identified in this comparison with respect to the observed data and the models, and describe the strategy used to calibrate the science data from GREAT/SOFIA during the first observing periods.
Journal ArticleDOI
Atomic Carbon in M82: Physical conditions derived from simultaneous observations of the [CI] fine structure submillimeter wave transitions
J. Stutzki,Urs U. Graf,S. Haas,Cornelia E. Honingh,D. Hottgenroth,Karl Jacobs,Rudolf Schieder,R. Simon,Johannes Staguhn,Gisbert Winnewisser,Robert N. Martin,W. L. Peters,Joseph P. McMullin +12 more
TL;DR: The first extragalactic detection of the neutral carbon [CI] 3P2-3P1 fine structure line at 809 GHz was reported in this paper, where the line was observed towards M82 simultaneously with the 3P1 -3P0 line at 492 GHz, providing a precise measurement of the J=2-1/J=1-0 integrated line ratio of 0.96 (on a [K km s^-1] -scale).
Journal ArticleDOI
The upGREAT 1.9 THz multi-pixel high resolution spectrometer for the SOFIA Observatory
Christophe Risacher,Rolf Güsten,J. Stutzki,Heinz-Wilhelm Hübers,A. Bell,Christof Buchbender,D. Büchel,Timea Csengeri,Urs U. Graf,Stefan Heyminck,Ronan Higgins,Cornelia E. Honingh,Karl Jacobs,Bernd Klein,Yoko Okada,A. Parikka,P. Pütz,Nicolas Reyes,Nicolas Reyes,O. Ricken,Denise Riquelme,R. Simon,Helmut Wiesemeyer +22 more
TL;DR: In this paper, the Stratospheric Observatory for Far-Infrared Astronomy (SOFIA) presented a new multi-pixel high resolution (R ≳ 107 ) spectrometer.