To determine a quasar's overall emitted photon flux across all wavelengths, you would need to measure its spectral energy distribution (SED). The SED represents the amount of energy emitted by the quasar at different wavelengths.
Here's a general approach to assess the overall energy output:
Collect Data: Obtain observational data of the quasar's flux measurements at various wavelengths. This data can come from different telescopes or instruments sensitive to different wavelength ranges (e.g., optical, infrared, X-ray).
Flux Calibration: Ensure that the collected flux measurements are properly calibrated and standardized. Calibration procedures involve comparing the measured flux to known standard stars or flux calibrators to establish an accurate flux scale.
Spectral Integration: Integrate the flux measurements over the entire wavelength range of interest to obtain the total energy emitted by the quasar. This integration involves summing up the flux values at each wavelength, taking into account the wavelength spacing and any instrumental response functions.
Correct for Redshift: Quasars are often located at significant distances, and their light is subject to redshift due to the expansion of the universe. Correct the observed wavelengths for the quasar's redshift to obtain the rest-frame wavelengths, which represent the true emitted wavelengths.
Account for Absorption: Some quasars may exhibit absorption features due to intervening material along the line of sight. Correct for any significant absorption features in the observed flux measurements, as they can affect the total energy output estimation.
Bolometric Correction: The observed flux measurements may cover only a limited range of wavelengths. To estimate the quasar's overall energy output, apply a bolometric correction. A bolometric correction factor takes into account the missing flux outside the observed range and provides an estimate of the total emitted energy.
Convert to Photon Flux: Finally, convert the energy flux into photon flux if you specifically want to assess the number of emitted photons. This conversion requires knowledge of the quasar's energy distribution at each wavelength and the energy associated with individual photons at those wavelengths.
It's important to note that accurately determining the overall emitted photon flux and energy output of a quasar can be a complex task due to various factors such as observational limitations, redshift effects, and corrections for absorption. Therefore, it often involves detailed modeling and analysis techniques tailored to the specific dataset and quasar properties.