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Far-infrared sources and diffuse emission in m31
| Content Provider | NASA Technical Reports Server (NTRS) |
|---|---|
| Author | Helou, George Xu, Cong |
| Copyright Year | 1994 |
| Description | A study on the far-infrared (FIR) emission of M31 has been carried out with the High Resolution (HiRes) maps (approx. 1 min) derived from IRAS data. Sixty-eight FIR sources are detected in M31, which in general coincide with optical HII regions, and contribute 15, 23, 29, and 23 percent to the fluxes in 12, 25, 60, and 100 micron bands, respectively. The remaining diffuse emission, which dominates the FIR emission of M31, is studied using a dust heating model which utilizes the UV and optical photometry maps and the HI maps available in the literature. It is found that the global dust-to-gas ratio in M31 disk is 6.5 10(exp -3), very close to the dust-to-gas ratio in the solar neighborhood. There is a significant galactocentric gradient of the dust-to-HI-gas ratio, with an e-folding scale length of 9 kpc. The diffuse dust correlates tightly with the HI gas. The model indicates that the non-ionizing UV (913-4000A) radiation from massive and intermediate massive stars contributes only about 30 percent of the heating of the diffuse dust, while the optical-NIR (4000-9000A) radiation from the old stellar population is responsible for the most of the heating. |
| File Size | 287767 |
| Page Count | 8 |
| File Format | |
| Alternate Webpage(s) | http://archive.org/details/NASA_NTRS_Archive_19950015344 |
| Archival Resource Key | ark:/13960/t0ps2q899 |
| Language | English |
| Publisher Date | 1994-04-01 |
| Access Restriction | Open |
| Subject Keyword | Documentation And Information Science Near Infrared Radiation Far Infrared Radiation Optical Measurement Cosmic Dust Infrared Sources Astronomy Ultraviolet Photometry Spaceborne Astronomy H Ii Regions Andromeda Galaxy Infrared Astronomy Infrared Astronomy Satellite Massive Stars Ntrs Nasa Technical Reports Server (ntrs) Nasa Technical Reports Server Aerodynamics Aircraft Aerospace Engineering Aerospace Aeronautic Space Science |
| Content Type | Text |
| Resource Type | Article |
