I have H alpha spectra of H II regions in our galaxy. In the paper, the x-axis is in units of km/s and the corresponding line width as well. From this, how can I get equivalent width of the H alpha line?

  • $\begingroup$ $v = c\Delta \lambda/\lambda_0$ $\endgroup$
    – ProfRob
    Commented Nov 15, 2020 at 21:58
  • $\begingroup$ It would be much better if you mentioned and linked to the paper and gave the actual value of the line width in km/s. The comment above works to first order, but if it's really wide the answer could turn out to be more interesting! $\endgroup$
    – uhoh
    Commented Nov 17, 2020 at 3:39
  • $\begingroup$ @uhoh- Thank You for replying. The link for the paper I am looking at is link. I needed to know the H alpha equivalent width of the H2 regions in units of wavelength. Am I missing something here? $\endgroup$
    – user1796
    Commented Nov 17, 2020 at 16:20


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