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Questions about the observed frequency range of the electromagnetic radiation of a celestial object.
2
votes
2
answers
1k
views
about H$_\alpha$ and H$_\beta$ lines in astronomical objects' spectra
Generally there may be some line ratio between the two lines.
If H$\alpha$ is strong, it is quite possible we can see H$_\beta$ too.
Is it possible we can see H$_\beta$, but can not see H$_\alpha$? …
6
votes
1
answer
191
views
Clarification of radio spectrum terminology
For a radio spectrum, when is it called thermal emission, synchrotron emission, self-absorbed synchrotron emission and inverted spectrum? They are all power-law and their difference is power-law index …
14
votes
3
answers
2k
views
How to detect emission lines in optical spectra?
Is there any handy module to detect emission lines in a spectrum like one we get from the Sloan Digital Sky Survey (SDSS)?
You can see there are many emission lines like Ha,OI in the spectrum below. …
2
votes
2
answers
581
views
How to tell whether an optical spectrum is featureless or just with a low S/N?
A featureless spectrum and a spectrum low S/N are very similar.
Is there a way to tell the difference between them?
2
votes
2
answers
890
views
How do I understand a brown dwarf with a M-type spectrum?
The reason we do not need to create a new stellar type is the spectra of brown dwarfs are more like red dwarf's spectra? …