Brightness map of the zodiacal emission from the AKARI IRC All-Sky Survey

Abstract

The first Japanese infrared space mission AKARI successfully scanned the whole sky with its two main instruments, the Infrared Camera (IRC) and the Far-Infrared Surveyor (FIS). The AKARI All-Sky Survey provides us with an invaluable opportunity to examine the zodiacal emission (ZE) over the entire sky in the leading as well as the trailing direction of the Earth's motion. We describe our efforts to reduce the ZE brightness map from the AKARI's survey in the 9 μm waveband. Compared with the interplanetary dust cloud model of Kelsall et al. (1998), the map requires an increase of the contribution of the resonance ring component to the ZE brightness by about 20%. We paid special attention to the north and south ecliptic pole brightnesses. The symmetry plane's inclination and longitude of ascending node need to be modified from those in Kelsall et al. (1998) to reach a best fit to the observed pole brightness difference.

Small-Scale Structure of the Zodiacal Dust Cloud Observed in Far-Infrared With Akari

“…However, from the results of the IRAS observations, it was found that there are many small-scale structures in the ZL distribution, http://pkas.kas.org such as asteroidal dust bands and a circumsolar resonance ring (Low et al, 1984;Dermott et al, 1984). It was also found that the sky brightness near the ecliptic plane observed with the IRAS and COBE/DIRBE is brighter towards the direction that trails the Earth's motion than towards the leading direction (Dermott et al, 1994;Reach et al, 1995), and this is confirmed with the AKARI mid-IR observations (Pyo et al, 2010).…”

AKARI far-infrared maps of the zodiacal dust bands

“…The Japanese satellite AKARI, a satellite dedicated to IR astronomical observations, was the third mission to survey the whole sky at mid-and far-IR wavelengths (Murakami et al 2007). Although most of the smooth ZE structure seen in the AKARI mid-and far-IR images can be reproduced well with the Kelsall or the Wright/Gorjian models, there are discrepancies on small scales (Pyo et al 2010;Kondo et al 2016). In particular, the intensities and the ecliptic latitudes of the peak positions of the asteroidal dust bands and the MMRs cannot be precisely reproduced with these models (Pyo et al 2010;Doi et al 2015;Kondo et al 2016).…”

“…To determine the brightness distribution of the ZE and the spatial structure of the IPD, fullsky surveys obtained with IR satellites are particularly powerful (e.g., Hauser et al 1984;Reach 1992;Reach et al 1997;Fixsen & Dwek 2002;Pyo et al 2010;Planck Collaboration et al 2014). …”

Modeling of the Zodiacal Light for the Akari Mid-Ir All-Sky Diffuse Maps

“…Kelsall et al (1998) made an IPD cloud model based on the COBE 10 photometric band data (hereafter the Kelsall model). This model has been used for removal of the zodiacal light from IR maps such as the IRAS, COBE, and http://pkas.kas.org AKARI maps (Miville-Deschênes & Lagache, 2005;Kelsall et al, 1998;Pyo et al, 2010). However, the Kelsall model does not fully reproduce the distribution of the IPD cloud; for example, there remains a residual component of the zodiacal light (∼1 MJy sr −1 ) around the ecliptic plane in the COBE 12 and 25 µm maps ( Figure 2c in Kelsall et al 1998).…”