IRSAM: The infrared extension of the Statistical Asteroid Model
Introduction:
Due to the relative stength of their apparent brightness at infrared wavelength
compared e.g. to Galactic stars, asteroids are among the dominant sources
at infrared wavelengths and can seriously affect
the infrared observations. To check/describe their impact on IR and submm
measurement a model is needed that can give the ephemerids describing most
asteroid families, brightness values (at least at one wavelength), and albedos
as well. These conditions are fulfilled by the
Statistical Asteroid Model (Tedesco et al., 2005, AJ, 129, 2869).
The model:
Our model provides the IR and submm fluxes of all minor planets in the
Statistical Asteroid Model (SAM),
using the Standard Thermal Model
(Lebofsky et al., 1986, Icarus, 68, 239), and therefore can be considered
as the IR and submm extension of the SAM. The celestial positions of the minor planets
are calculated for the time span 2000-01-01...2012-12-31, and some quantities,
describing their impact on the IR and submm measurements (fluctuations powers,
expected counts, surface brightness contribution) are derived
for a specific sky position, date and wavelength. The model is
accessible for the community through a
web-interface. If you
use the results of our model in your publication, please, refer to the
papers below. You can read more about infrared confusion noise
here.
Mission average maps:
The general impact of asteroids on the infrared and submillimetre measurements can
be well described by 'mission-average' maps for a specific wavelength,
i.e. average maps of full fluctuation power maps of different dates. Mission-average
maps are presented in the heliecliptic coordinate system
[|λ-λo|- β where λ is the ecliptic longitude,
λo is the ecliptic longitude of the Sun, and β is the
ecliptic latitude].
For a detailed description of mission average maps, see the related papers below.
FITS cube of mission-average maps for multiple wavelengths:
df0_mamap_cube.fits
Mission-average number counts:
ntot_mamap.fits
Effective solid angles to calculate confusion noise from fluctuation powers:
Instrument |
PACS† |
PACS† |
PACS† |
SPIRE† |
SPIRE† |
SPIRE† |
Wavelength (μm) |
70 |
100 |
160 |
250 |
350 |
500 |
Ωpixel (sr) |
2.56×10-10 |
2.56×10-10 |
1.02×10-9 |
5.33×10-9 |
1.15×10-8 |
2.13×10-8 |
Ωeff (sr) |
3.87×10-10 |
5.67×10-10 |
1.80×10-9 |
5.89×10-9 |
1.21×10-8 |
2.35×10-8 |
† PACS and SPIRE are
instruments of the Herschel Space Observatory.
More information on the currently used solid angles for the
photometric bands above can be found in
The Herschel Confusion Noise Estimator, V015, release note .
Related papers:
Kiss, Cs.,
Pál, A., Müller, Th., Ábrahám, P., 2006,
"An asteroid model of the mid- and far-infrared sky", In:
Proceedings of the 4th Workshop of Young Researchers in Astronomy & Astrophysics; Budapest,
Hungary, 11-13 January, 2006; Publications of the Astronomy Department of the Eötvös
University (PADEU), Edited by E. Forgács-Dajka, Vol. 17., p. 135
Kiss, Cs.,
Pál, A., Müller, Th., Ábrahám, P., 2006,
"Confusion noise due to asteroids: from mid-IR to submm wavelengths",
poster, Visions of infrared astronomy, March 20-22, 2006, Paris
Kiss, Cs.,
Pál, A., Müller, Th., Ábrahám, P., 2008,
"The impact of main belt asteroids on infrared-submillimetre photomerty
and source counts", Astronomy & Astrophysics, 478, 605-613
A&A
PAPER
A&A paper at astro-ph
KISAG, Solar System research pages
Konkoly Infrared & Space Astronomy Group
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