What wavelength range specifically characterizes the Far-Infrared (FIR) useful for tracing dust re-radiation?
$25 ext{ extmu m}$ to $350 ext{ extmu m}$
The Far-Infrared (FIR) regime is crucial for estimating the total Star Formation Rate because it captures the energy that was originally emitted by young, massive stars in the UV but subsequently absorbed by surrounding interstellar dust. This absorbed energy is then re-radiated by the heated dust grains at longer, cooler wavelengths. The specific spectral window defined as Far-Infrared for this purpose spans wavelengths ranging from approximately $25 ext{ extmu m}$ up to $350 ext{ extmu m}$. Measurements taken within this range, such as luminosity at $60 ext{ extmu m}$ or $100 ext{ extmu m}$, provide a comprehensive view of the total stellar energy output, encompassing both obscured and visible young stars.
