An Investigation of Longitudinal Dependence of the Temperature of the Dust in the Local Interstellar Medium
Abstract
Using the IRAS Sky Survey Atlas, we have investigated the spatial and temperature structure of the the local interstellar medium in the northern half of the first and second quadrants of the Galaxy (10(deg) <= b <= 50(deg) & 42(deg) <= l <= 146(deg) ). The ratio of I_{60 mu{m}} vs I_{100 mu{m}} is found to be 0.1735 (+/- 0.0004) indicating an average dust temperature of 24K impling that the 60 mu{m} and 100 mu{m} intensities are primarily produced by the thermal emission of large dust grains in thermal equilibrium with the interstellar radiation field. In addition, we have found a significant longitudinal dependence for the temperature associated with the interstellar dust. Using 1^{\circ}$ wide longitude bins, we find the average dust temperature varies by more than 20% with a general gradient of decreasing temperature with increasing longitude. Further we find that the total surface brightness, in the same longitude bins, is anti-correlated with the temperature indicating that the hotter dust is associated with regions of lower dust quantity.
- Publication:
-
American Astronomical Society Meeting Abstracts #186
- Pub Date:
- May 1995
- Bibcode:
- 1995AAS...186.3512C