Detection of a Far IR Excess with DIRBE at 60 and 100 Microns

Astronomy and Astrophysics – Astrophysics

Scientific paper

Rate now

  [ 0.00 ] – not rated yet Voters 0   Comments 0

Details

43 pages, 9 figures, submitted to ApJ

Scientific paper

10.1086/317177

From analysis of the DIRBE weekly averaged sky maps, we have detected substantial flux in the 60 and 100 micron channels in excess of expected zodiacal and Galactic emission. Two methods are used to separate zodiacal light from more distant emission. Method I makes use of the time-dependence of the North-South annual variation observed at the ecliptic poles. This method is robust against errors in the inter-planetary dust (IPD) model, but does not demonstrate isotropy of the background. Method II measures the ecliptic latitude dependence of the dust over a range of ecliptic latitudes at solar elongation e=90 degrees. This allows the excess to be determined in each week of the DIRBE mission for high redundancy, but the results depend weakly on the IPD model. Both methods give consistent results at 60 and 100 microns. The observed signal is consistent with an isotropic background at the level \nu I_\nu = 28.1 +- 1.8 +- 7(syst) nW/m^2/sr at 60 microns and 24.6 +- 2.5 +- 8 nW/m^2/sr at 100 microns. The IR excess detected at 140 and 240 microns by these methods agrees with previous measurements, which are thought to be the cosmic infra-red background (CIB). The detections at 60 and 100 microns are new. While this new excess is not necessarily the CIB, we have ruled out all known sources of emission in the solar system and Galaxy. We therefore tentatively interpret this signal as the CIB and consider the implications of such energy production from the viewpoint of star formation efficiency and black hole accretion efficiency. However, the IR excess exceeds limits on the CIB derived from the inferred opacity of the IGM to observed TeV photons, thus casting doubt on this interpretation. There is currently no satisfactory explanation for the 60-100 micron excess.

No associations

LandOfFree

Say what you really think

Search LandOfFree.com for scientists and scientific papers. Rate them and share your experience with other people.

Rating

Detection of a Far IR Excess with DIRBE at 60 and 100 Microns does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.

If you have personal experience with Detection of a Far IR Excess with DIRBE at 60 and 100 Microns, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Detection of a Far IR Excess with DIRBE at 60 and 100 Microns will most certainly appreciate the feedback.

Rate now

     

Profile ID: LFWR-SCP-O-573206

  Search
All data on this website is collected from public sources. Our data reflects the most accurate information available at the time of publication.