AEGIS: The Astrophysics Experiment for Grating and Imaging Spectroscopy
About AEGIS:
White Paper response to NASA RFI
January 2012 AAS Poster
Effective area:
The plots below show the AEGIS effective area (vs wavelength (top) or energy (bottom)). The lower colored curves are the area per order and grating period (2000A or 2300A; orders 1-13 with lowest order rightmost on the wavelength axis). The upper gray curve is the sum of the lower curves. These areas were derived from end-to-end ray-trace simulations. They include the effects of (dithered) chip gaps, which show as the sharp downward spikes. The curves also contain a bit of noise (<3%), since they are derived from a Monte-Carlo ray-trace.
Resolving Power
The resolving power ( defined as wavelength / fwhm) has a requirement of being >= 3000. The ray-trace simulations show about 4000 (red dots in the figure below) but do not contain all expected aberrations (such as mirror element mis-alignments). Hence, we assume R=3000 at the center of the array. Since the trend along the displersion in the simulations is fairly flat, we assume R=constant with dispersion angle. The black line below is what is expected from an ideal grating spectrometer.
Response Matrices
The above effective areas and resolving power are packaged in standard response formats ("ARF" and "RMF"), assuming either a Gaussian or Lorentzian instrumental line profile. The responses are available for the combination of all orders and gratings, or for the individual orders. You can find a detailed description and the files at http://web.mit.edu/~dph/www/aegis_responses/.
Science:
Payload:
Mission:
