Search Publications
The Herschel-PACS photometer calibration. Point-source flux calibration for scan maps
Moór, Attila; Sauvage, Marc; Okumura, Koryo +9 more
This paper provides an overview of the PACS photometer flux calibration concept, in particular for the principal observation mode, the scan map. The absolute flux calibration is tied to the photospheric models of five fiducial stellar standards ( α Boo, α Cet, α Tau, β And, γ Dra). The data processing steps to arrive at a consistent and homogeneou…
Herschel celestial calibration sources. Four large main-belt asteroids as prime flux calibrators for the far-IR/sub-mm range
Pearson, Chris; Lim, Tanya; Linz, Hendrik +9 more
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…
The pointing system of the Herschel space observatory. Description, Calibration, Performance and improvements
Marston, Anthony; Linz, Hendrik; Merín, Bruno +13 more
We present the activities carried out to calibrate and characterise the performance of the elements of attitude control and measurement on board the Herschel spacecraft. The main calibration parameters and the evolution of the indicators of the pointing performance are described, from the initial values derived from the observations carried out in…
SPIRE point source photometry: within the Herschel interactive processing environment (HIPE)
Griffin, Matt; Pearson, Chris; Lim, Tanya +11 more
The different algorithms appropriate for point source photometry on data from the SPIRE instrument on-board the Herschel Space Observatory, within the Herschel Interactive Processing Environment (HIPE) are compared. Point source photometry of a large ensemble of standard calibration stars and dark sky observations is carried out using the 4 major …
Optimized Herschel/PACS photometer observing and data reduction strategies for moving solar system targets
Hartogh, P.; Pál, A.; Lellouch, E. +10 more
The "TNOs are Cool!: A survey of the trans-Neptunian region" is a Herschel Open Time Key Program that aims to characterize planetary bodies at the outskirts of the Solar System using PACS and SPIRE data, mostly taken as scan-maps. In this paper we summarize our PACS data reduction scheme that uses a modified version of the standard pipeline for ba…
Herschel SPIRE FTS relative spectral response calibration
Valtchanov, Ivan; Hopwood, Rosalind; Lu, Nanyao +9 more
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 Telescop…
Herschel SPIRE FTS telescope model correction
Valtchanov, Ivan; Hopwood, Rosalind; Lu, Nanyao +8 more
Emission from the Herschel telescope is the dominant source of radiation for the majority of SPIRE Fourier transform spectrometer (FTS) observations, despite the exceptionally low emissivity of the primary and secondary mirrors. Accurate modelling and removal of the telescope contribution is, therefore, an important and challenging aspect of FTS c…
Herschel SPIRE fourier transform spectrometer: calibration of its bright-source mode
Valtchanov, Ivan; Hopwood, Rosalind; Naylor, David A. +10 more
The Fourier Transform Spectrometer (FTS) of the Spectral and Photometric Imaging REceiver (SPIRE) on board the ESA Herschel Space Observatory has two detector setting modes: (a) a nominal mode, which is optimized for observing moderately bright to faint astronomical targets, and (b) a bright-source mode recommended for sources significantly bright…
Relative pointing offset analysis of calibration targets with repeated observations with Herschel-SPIRE Fourier-transform spectrometer
Valtchanov, Ivan; Hopwood, Rosalind; Lu, Nanyao +9 more
We present a method to derive the relative pointing offsets for SPIRE Fourier-Transform Spectrometer (FTS) solar system object (SSO) calibration targets, which were observed regularly throughout the Herschel mission. We construct ratios R obs( ν) of the spectra for all observations of a given source with respect to a reference. The refe…
The effect of sideband ratio on line intensity for Herschel/HIFI
Braine, Jonathan; Ossenkopf, Volker; Higgins, Ronan +8 more
The Heterodyne Instrument for the Far Infrared (HIFI) on board the Herschel Space Observatory is composed of a set of fourteen double sideband mixers. We discuss the general problem of the sideband ratio (SBR) determination and the impact of an imbalanced sideband ratio on the line calibration in double sideband heterodyne receivers. The HIFI SBR …