مقاله Herschel celestial calibration sources : تی پی بین

خلاصه مقاله

Celestial standards play a major role in observational astrophysics. They are needed to characterise the performance of instruments and are paramount for photometric calibration. During the Herschel Calibration Asteroid Preparatory Programme approximately 50 asteroids have been established as far-IR/sub-mm/mm calibrators for Herschel. The selected asteroids fill the flux gap between the sub-mm/mm calibrators Mars, Uranus and Neptune, and the mid-IR bright calibration stars. All three Herschel instruments observed asteroids for various calibration purposes, including pointing tests, absolute flux calibration, relative spectral response function, observing mode validation, and cross-calibration aspects. Here we present newly established models for the four large and well characterized main-belt asteroids (1) Ceres, (2) Pallas, (4) Vesta, and (21) Lutetia which can be considered as new prime flux calibrators. The relevant object-specific properties (size, shape, spin-properties, albedo, thermal properties) are well established. The seasonal (distance to Sun, distance to observer, phase angle, aspect angle) and daily variations (rotation) are included in a new thermophysical model setup for these targets. The thermophysical model predictions agree within 5 % with the available (and independently calibrated) Herschel measurements. The four objects cover the flux regime from just below 1,000 Jy (Ceres at mid-IR N-/Q-band) down to fluxes below 0.1 Jy (Lutetia at the longest wavelengths). Based on the comparison with PACS, SPIRE and HIFI measurements and pre-Herschel experience, the validity of these new prime calibrators ranges from mid-infrared to about 700 μm, connecting nicely the absolute stellar reference system in the mid-IR with the planet-based calibration at sub-mm/mm wavelengths.

نویسندگان

Thomas Müller [ Max Planck Institute for Extraterrestrial Physics, PO Box 1312, Giessenbachstrasse, 85741, Garching, Germany ]

Zoltán Balog [ Max Planck Institute for Astronomy, Königstuhl 17, 69117, Heidelberg, Germany ]

Markus Nielbock [ Max Planck Institute for Astronomy, Königstuhl 17, 69117, Heidelberg, Germany ]

Tanya Lim [ Space Science and Technology Department, RAL, Didcot, OX11 0QX, Oxon, UK ]

David Teyssier [ European Space Astronomy Centre (ESAC), ESA, Villanueva de la Cañada, 28691, Madrid, Spain ]

کلمات کلیدی

Herschel Space Observatory PACS SPIRE HIFI Far infrared Instrumentatio n Calibration Celestial standards Asteroids

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Experimental Astronomy 2013

Many new instruments for observing astronomical objects at a variety of wavelengths have been and are continually being developed. Consequently, a vast amount of effort is being put into new data analysis techniques to cope with rivers of data collected by these instruments.Experimental Astronomy is a medium for the publication of papers of contemporary scientific interest on astrophysical instrumentation and methods necessary for the conduct of astronomy at all wavelength fields.Experimental Astronomy publishes full-length articles, research letters and reviews on developments in detection techniques, instruments, and data analysis and image processing techniques. Occasional special issues are published, giving an in-depth presentation of the instrumentation and/or analysis connected with specific projects, such as satellite experiments or ground-based telescopes, or of specialized techniques.Commonly used title abbreviations: Exp. Astron., Exp Astron, ExA

حوزه های تحت پوشش : Astronomy, Observations and Techniques, Statistics for Engineering, Physics, Computer Science, Chemistry and Earth Sciences