Bluesky Spectroscopy

Lethbridge, Canada

Bluesky Spectroscopy

Lethbridge, Canada
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Fulton T.,Bluesky Spectroscopy | Fulton T.,University of Lethbridge | Hopwood R.,Imperial College London | Baluteau J.-P.,Aix - Marseille University | And 12 more authors.
Experimental Astronomy | Year: 2014

Herschel/SPIRE Fourier transform spectrometer (FTS) observations contain emission from both the Herschel Telescope and the SPIRE Instrument itself, both of which are typically orders of magnitude greater than the emission from the astronomical source, and must be removed in order to recover the source spectrum. The effects of the Herschel Telescope and the SPIRE Instrument are removed during data reduction using relative spectral response calibration curves and emission models. We present the evolution of the methods used to derive the relative spectral response calibration curves for the SPIRE FTS. The relationship between the calibration curves and the ultimate sensitivity of calibrated SPIRE FTS data is discussed and the results from the derivation methods are compared. These comparisons show that the latest derivation methods result in calibration curves that impart a factor of between 2 and 100 less noise to the overall error budget, which results in calibrated spectra for individual observations whose noise is reduced by a factor of 2-3, with a gain in the overall spectral sensitivity of 23 % and 21 % for the two detector bands, respectively. © 2014 Springer Science+Business Media Dordrecht.


Swinyard B.M.,Rutherford Appleton Laboratory | Hartogh P.,Max Planck Institute for Solar System Research | Sidher S.,Rutherford Appleton Laboratory | Fulton T.,Bluesky Spectroscopy | And 43 more authors.
Astronomy and Astrophysics | Year: 2010

We have obtained the first continuous disk averaged spectrum of Mars from 450 to 1550 Ghz using the Herschel-SPIRE Fourier-transform spectrometer. The spectrum was obtained at a constant resolution of 1.4 GHz across the whole band. The flux from the planet is such that the instrument was operated in "bright source" mode to prevent saturation of the detectors. This was the first successful use of this mode and in this work we describe the method used for observing Mars together with a detailed discussion of the data reduction techniques required to calibrate the spectrum. We discuss the calibration accuracy obtained and describe the first comparison with surface and atmospheric models. In addition to a direct photometric measurement of the planet the spectrum contains the characteristic transitions of 12CO from J 5-4 to J 13-12 as well as numerous H2O transitions. Together these allow the comparison to global atmospheric models allowing the mean mixing ratios of water and 12CO to be investigated. We find that it is possible to match the observed depth of the absorption features in the spectrum with a fixed water mixing ratio of 1×10-4 and a 12CO mixing ratio of 9×10-4. © 2010 ESO.


Hartogh P.,Max Planck Institute for Solar System Research | Jarchow C.,Max Planck Institute for Solar System Research | Lellouch E.,University of Paris Descartes | De Val-Borro M.,Max Planck Institute for Solar System Research | And 48 more authors.
Astronomy and Astrophysics | Year: 2010

We report on an initial analysis of Herschel/HIFI observations of hydrogen chloride (HCl), hydrogen peroxide (H2O2), and molecular oxygen (O2) in the Martian atmosphere performed on 13 and 16 April 2010 (Ls ∼77°). We derived a constant volume mixing ratio of 1400 ± 120 ppm for O2 and determined upper limits of 200 ppt for HCl and 2 ppb for H2O2. Radiative transfer model calculations indicate that the vertical profile of O2 may not be constant. Photochemical models determine the lowest values of H 2O2 to be around Ls ∼75° but overestimate the volume mixing ratio compared to our measurements. © 2010 ESO.


Hartogh P.,Max Planck Institute for Solar System Research | Blecka M.I.,Polish Academy of Sciences | Jarchow C.,Max Planck Institute for Solar System Research | Sagawa H.,Max Planck Institute for Solar System Research | And 50 more authors.
Astronomy and Astrophysics | Year: 2010

We report on the initial analysis of Herschel/HIFI carbon monoxide (CO) observations of the Martian atmosphere performed between 11 and 16 April 2010. We selected the (7-6) rotational transitions of the isotopes 13CO at 771 GHz and C18O and 768 GHz in order to retrieve the mean vertical profile of temperature and the mean volume mixing ratio of carbon monoxide. The derived temperature profile agrees within less than 5 K with general circulation model (GCM) predictions up to an altitude of 45 km, however, show about 12-15 K lower values at 60 km. The CO mixing ratio was determined as 980 ± 150 ppm, in agreement with the 900 ppm derived from Herschel/SPIRE observations in November 2009. © 2010 ESO.

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