T. Takagi, H. Matsuhara, T. Goto, H. Hanami, M. Im, T. Ishigaki, H. M. Lee, M. Malkan, Y. Ohyama, S. Oyabu, C. P. Pearson, S. Serjeant, T. Wada, G. J. White
We present a new catalogue of mid-IR sources using the AKARI NEP-Deep survey.
The InfraRed Camera (IRC) onboard AKARI has a comprehensive mid-IR wavelength
coverage with 9 photometric bands at 2 - 24 micron. We utilized all of these
bands to cover a nearly circular area adjacent to the North Ecliptic Pole
(NEP). We designed the catalogue to include most of sources detected in 7, 9,
11, 15 and 18 micron bands, and found 7284 sources in a 0.67 deg^2 area. From
our simulations, we estimate that the catalogue is ~80 per cent complete to 200
micro Jy at 15 - 18 micron, and ~10 per cent of sources are missed, owing to
source blending. Star-galaxy separation is conducted using only AKARI
photometry, as a result of which 10 per cent of catalogued sources are found to
be stars. The number counts at 11, 15, 18, and 24 micron are presented for both
stars and galaxies. A drastic increase in the source density is found in
between 11 and 15 micron at the flux level of ~300 micro Jy. This is likely due
to the redshifted PAH emission at 8 micron, given our rough estimate of
redshifts from an AKARI colour-colour plot. Along with the mid-IR source
catalogue, we present optical-NIR photometry for sources falling inside a
Subaru/Sprime-cam image covering part of the AKARI NEP-Deep field, which is
deep enough to detect most of AKARI mid-IR sources, and useful to study optical
characteristics of a complete mid-IR source sample.
View original:
http://arxiv.org/abs/1201.0797
No comments:
Post a Comment