137 research outputs found
The Herschel SPIRE Fourier Transform Spectrometer Spectral Feature Finder I. The Spectral Feature Finder and Catalogue
We provide a detailed description of the Herschel-SPIRE Fourier Transform
Spectrometer (FTS) Spectral Feature Finder (FF). The FF is an automated process
designed to extract significant spectral features from SPIRE FTS data products.
Optimising the number of features found in SPIRE-FTS spectra is challenging.
The wide SPIRE-FTS frequency range (447-1568 GHz) leads to many molecular
species and atomic fine structure lines falling within the observed bands. As
the best spectral resolution of the SPIRE-FTS is ~1.2 GHz, there can be
significant line blending, depending on the source type. In order to find, both
efficiently and reliably, features in spectra associated with a wide range of
sources, the FF iteratively searches for peaks over a number of signal-to-noise
ratio (SNR) thresholds. For each threshold, newly identified features are
rigorously checked before being added to the fitting model. At the end of each
iteration, the FF simultaneously fits the continuum and features found, with
the resulting residual spectrum used in the next iteration. The final FF
products report the frequency of the features found and the associated SNRs.
Line flux determination is not included as part of the FF products, as
extracting reliable line flux from SPIRE-FTS data is a complex process that
requires careful evaluation and analysis of the spectra on a case-by-case
basis. The FF results are 100% complete for features with SNR greater than 10
and 50-70% complete at SNR of 5. The FF code and all FF products are publicly
available via the Herschel Science Archive.Comment: 20 pages, 8 figures, 8 tables, final version accepted by MNRAS June
202
Der Einfluss der Kapazitätsgröße und -auslastung auf den Kostenverlauf ausgewählter Hilfskostenstellen von Molkereien - Abteilung Dampfversorgung
Die Kostenanalyse zur Bestimmung des Einflusses der Kapazitätsgröße und -auslastung auf den Kostenverlauf von Hilfskostenstellen (Hilfsabteilungen) erfolgt mit Hilfe von Modellkalkulationen. Eine spezielle Form der Teilkostenrechnung ermöglicht die Zurechnung der Kosten nach Kostenkategorien (jahresfix, tagesfix, ggf. chargenfix und mengenproportional) auf die entsprechenden Kostenträger (z. B. Kälte, Dampf) der jeweiligen Hilfskostenstelle. Durch computergestützte Simulationen können die Auswirkungen der verschiedenen Kosteneinflußfaktoren im einzelnen quantifiziert werden
In-orbit performance of the Herschel/SPIRE imaging Fourier transform spectrometer: lessons learned
The Spectral and Photometric Imaging Receiver (SPIRE) is one of three scientific instruments on board the European Space Agency's Herschel Space Observatory which ended its operational phase on 29 April 2013. The low to medium resolution spectroscopic capability of SPIRE is provided by an imaging Fourier transform spectrometer (iFTS) of the Mach-Zehnder configuration. With their high throughput, broad spectral coverage, and variable resolution, coupled with their well-defined instrumental line shape and intrinsic wavelength and intensity calibration, iFTS are becoming increasingly common in far-infrared space astronomy missions. The performance of the SPIRE imaging spectrometer will be reviewed and example results presented. The lessons learned from the measured performance of the spectrometer as they apply to future missions will be discussed
Better Together: Examining the Role of Collaborative Ethnographic Documentary in Organizational Research
Despite growing interest in video-based methods in organizational research, the use of collaborative
ethnographic documentaries is rare. Organizational research could benefit from the inclusion of
collaborative ethnographic documentaries a) to enable the participation of ‘difficult to research’
groups and better access the material, embodied or sensitive dimensions of work and organizing, and
b) to assist in dissemination of findings to wider audiences. To increase understanding of this under explored method, the authors first review the available literature and consider strengths, limitations
and ethical concerns in comparison with traditional ethnography and other video-based methods.
Using recent data collected on working class men doing ‘dirty work’, the authors then illustrate the
use of collaborative ethnographic documentary as an investigative tool - capturing often concealed,
embodied and material dimensions of work; and a reflective tool - elaborating and particularizing
participants’ narrative accounts. It is concluded that collaborative ethnographic documentary
facilitates greater trust and communication between researchers and participants, triggering richer
exploration of participants’ experiences, in turn strengthening theoretical insights and practical impact
of the research
Empirical modelling of the BLASTPol achromatic half-wave plate for precision submillimetre polarimetry
A cryogenic achromatic half-wave plate (HWP) for submillimetre astronomical polarimetry
has been designed, manufactured, tested and deployed in the Balloon-borne Large-Aperture
Submillimeter Telescope for Polarimetry (BLASTPol). The design is based on the five-slab
Pancharatnam recipe and itworks in thewavelength range 200–600 μm, making it the broadestband
HWP built to date at (sub)millimetre wavelengths. The frequency behaviour of the HWP
has been fully characterized at room and cryogenic temperatures with incoherent radiation
from a polarizing Fourier transform spectrometer. We develop a novel empirical model, complementary
to the physical and analytical ones available in the literature, that allows us to
recover the HWP Mueller matrix and phase shift as a function of frequency and extrapolated
to 4 K. We show that most of the HWP non-idealities can be modelled by quantifying one
wavelength-dependent parameter, the position of the HWP equivalent axes, which is then readily
implemented in a map-making algorithm. We derive this parameter for a range of spectral
signatures of input astronomical sources relevant to BLASTPol, and provide a benchmark
example of how our method can yield improved accuracy on measurements of the polarization
angle on the sky at submillimetre wavelengths
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