English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Plus annual

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Tools annual

Global: Zendy Free Plan

Global: Zendy Tools monthly

Global: Zendy Plus monthly

Celestial standards play a major role in observational astrophysics. They areneeded to characterise the performance of instruments and are paramount forphotometric calibration. During the Herschel Calibration Asteroid PreparatoryProgramme approximately 50 asteroids have been established as far-IR/sub-mm/mmcalibrators for Herschel. The selected asteroids fill the flux gap between thesub-mm/mm calibrators Mars, Uranus and Neptune, and the mid-IR brightcalibration stars. All three Herschel instruments observed asteroids forvarious calibration purposes, including pointing tests, absolute fluxcalibration, relative spectral response function, observing mode validation,and cross-calibration aspects. Here we present newly established models for thefour large and well characterized main-belt asteroids (1) Ceres, (2) Pallas,(4) Vesta, and (21) Lutetia which can be considered as new prime fluxcalibrators. 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 dailyvariations (rotation) are included in a new thermophysical model setup forthese targets. The thermophysical model predictions agree within 5% with theavailable (and independently calibrated) Herschel measurements. The fourobjects cover the flux regime from just below 1,000 Jy (Ceres at mid-IRN-/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-Herschelexperience, the validity of these new prime calibrators ranges frommid-infrared to about 700 micron, connecting nicely the absolute stellarreference system in the mid-IR with the planet-based calibration at sub-mm/mmwavelengths.

Herschel celestial calibration sources: Four large main-belt asteroids as prime flux calibrators for the far-IR/sub-mm range