# How to convert flux from counts to erg.

1. Nov 8, 2012

### RHK

Hello everyone.
I am trying to translate the flux of a source observed by a telescope, in different units.
In my case, I have the flux equal to counts/cm^2/sec in a given energy band (15-50 keV) and I want to translate this information in erg/cm^2/sec, in the same energy band
Here you can find an example: http://heasarc.gsfc.nasa.gov/docs/swift/results/transients/weak/GX304-1.png

Does anyone know how can I do that?

Every suggestion is really appreciated.
Ciao

2. Nov 8, 2012

### SHISHKABOB

each count is just a photon with that specific energy level, so you just have to multiply the number of photons by the energy of the photons. Then of course convert from keV to erg, which just means multiplying by some conversion constants.

er wait, I think I misread the graph, sorry >.> what's on the bottom axis?

3. Nov 8, 2012

### RHK

The time, in MJD (modified julian date, it is like "days").

4. Nov 8, 2012

### SHISHKABOB

oh, I see, I'm sorry but I thought I could help but I don't know either