Dust affects our view of the distant universe!
Stars convert hydrogen into heavier elements and release them into the interstellar medium (via supernova, etc). These particles absorb light at certain wavelengths, which creates a big problem to the study star forming regions.
Dust particles will absorb high energy light that is emitted from star forming regions (the H-alpha regions). The luminosity that we receive is the luminosity from star formation - the absorption by dust. It is important to correct for the dust affects. It helps us correctly calculate the initial mass function and star formation rates. If we knew how much dust is in the interstellar atmosphere, then we could calculate the true luminosities of star forming regions. This data could help theorists better approximate the initial mass function and star forming rates.
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| The red ring around the galaxy is dust |
How and why does dust matter?
Dust particles will absorb high energy light that is emitted from star forming regions (the H-alpha regions). The luminosity that we receive is the luminosity from star formation - the absorption by dust. It is important to correct for the dust affects. It helps us correctly calculate the initial mass function and star formation rates. If we knew how much dust is in the interstellar atmosphere, then we could calculate the true luminosities of star forming regions. This data could help theorists better approximate the initial mass function and star forming rates.
How to measure the amount of dust?
Dust emits light in IR range. Here is a plot of luminosity of distant star forming galaxies.
As you can see, our IR detectors are not sensitive enough to calculate the luminosity from dust. This doesn't mean that we have to give up. There is a very interesting method to estimate the amount of dust know as stacking method.
We use stacking method to cancel out the effects of random disturbances to see any peaks (in IR) in star forming regions. Basic idea is to average luminosities from different IR images to see any peaks.
Procedure:
Look at different regions of sky and find as many star forming regions as you can from H(alpha) break from UV/Visible pictures.
Take IR images of these regions and cut out star forming areas. Now average fluxes from these cutouts and hope that you see some peak. Doing this should make all the disturbances cancel out, and reveal the small peak in the flux.
Special Thanks to Dr. Naveen Reddy
We use stacking method to cancel out the effects of random disturbances to see any peaks (in IR) in star forming regions. Basic idea is to average luminosities from different IR images to see any peaks.
Procedure:
Look at different regions of sky and find as many star forming regions as you can from H(alpha) break from UV/Visible pictures.
Take IR images of these regions and cut out star forming areas. Now average fluxes from these cutouts and hope that you see some peak. Doing this should make all the disturbances cancel out, and reveal the small peak in the flux.
Special Thanks to Dr. Naveen Reddy
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