| Type |
Journal Article |
| Names |
N. Odegard, R. G. Arendt, E. Dwek, L. M. Haffner, M. G. Hauser, R. J. Reynolds |
| Publication |
The Astrophysical Journal |
| Volume |
667 |
| Issue |
1 |
| Pages |
11-25 |
| Date |
September 1, 2007 |
| URL |
http://adsabs.harvard.edu/abs/2007ApJ...667...11O |
| Library Catalog |
NASA ADS |
| Abstract |
Determination of the cosmic infrared background (CIB) at far-infrared
wavelengths using COBE DIRBE data is limited by the accuracy to which
foreground interplanetary and Galactic dust emission can be modeled and
subtracted. Most previous determinations of the far-infrared CIB were
based on the detection of residual isotropic emission in sky maps from
which the emission from interplanetary dust and the neutral interstellar
medium were removed. In this paper we use the Wisconsin Hα Mapper
(WHAM) Northern Sky Survey as a tracer of the ionized medium to examine
the effect of this foreground component on determination of the CIB. We
decompose DIRBE far-infrared data for five high Galactic latitude
regions into H I- and Hα-correlated components and a residual
component. We find the Hα-correlated component to be consistent
with zero for each region, yielding CIB results that are essentially the
same as those previously derived by the COBE DIRBE team:
νIν(nW m-2 sr-1)<75, <32,
=25+/-8, and =13+/-3 at 60, 100, 140, and 240 μm, respectively (upper
limits are 2 σ). For comparison, the estimated integrated light
from galaxies based on Spitzer 160 μm source counts is 13.7+/-1.7 and
10.7+/-1.4 nW m-2 sr-1 at 140 and 240 μm,
respectively. We derive upper limits on the 100 μm emissivity of the
ionized medium that are typically about 40% of the 100 μm emissivity
of the neutral atomic medium. If Hα is not a reliable tracer of
far-infrared emission, we show that our analysis would underestimate the
emissivity of the ionized medium and could slightly overestimate the
CIB. |
| Tags |
Cosmology: Diffuse Radiation, Galaxy: General, ISM: General, cosmology: observations, infrared: ISM |