In:
Publications of the Astronomical Society of Japan, Oxford University Press (OUP), Vol. 59, No. sp2 ( 2007-10-10), p. S557-S569
Abstract:
We present an initial analysis of AKARI 18$\mu $m-selected galaxies using all 9 photometric bands at 2–24$\mu $m available in the Infrared Camera (IRC), in order to demonstrate new capabilities of AKARI cosmological surveys with this unprecedented wavelength coverage at mid-infrared (MIR) bands. We detected 72 sources at 18$\mu $m in an area of 50.2 arcmin$^2$ in the AKARI/IRC monitor field towards the North Ecliptic Pole (NEP). From this sample, 25 galaxies with probable redshifts of $z \gtrsim$ 0.5 were selected with a single colour cut (N2$-$N3$\gt$ 0.1) for a detailed spectral energy distribution (SED) analysis with ground-based $BVRi'z'JK$ data. Using an SED radiative transfer model of starbursts covering the wavelength range UV–submm, we derived photometric redshifts from the optical-MIR SEDs of 18$\mu $m-selected galaxies. From the best-fit SED models, we showed that the IRC all-band photometry is capable of tracing a steep rise in the flux at the blue side of the polycyclic aromatic hydrocarbon (PAH) 6.2$\mu $m emission feature. This indicates that the IRC all-band photometry is useful to constrain the redshift of infrared galaxies, specifically for dusty galaxies with a less prominent 4000Å break. Also, we found that the flux dip between the PAH 7.7 and 11.2$\mu $m emission feature is recognizable in the observed SEDs of galaxies at $z \sim 1$. This pilot study suggests the possibility of detecting many interesting galaxy properties in the NEP-Deep and Wide surveys, such as a systematic difference in SEDs between high–and low-$z$ Ultra-Luminous InfraRed Galaxies, and a large variation of the PAH inter-band strength ratio in galaxies at high redshifts.
Type of Medium:
Online Resource
ISSN:
2053-051X
,
0004-6264
DOI:
10.1093/pasj/59.sp2.S557
Language:
English
Publisher:
Oxford University Press (OUP)
Publication Date:
2007
detail.hit.zdb_id:
2206640-8
detail.hit.zdb_id:
2083084-1
SSG:
16,12
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