27-10-2012, 03:05 PM
Astrophysical Plasmadynmaic Explorer (APEX): A High Resolution Spectroscopic Observatory
ABSTRACT
EUVE and the ROSAT WFC have left a tremendous legacy in astrophysics at EUV wavelengths. More recently, Chandra
and XMM-Newton have demonstrated at X-ray wavelengths the power of high-resolution astronomical spectroscopy, which
allows the identification of weak emission lines, the measurement of Doppler shifts and line profiles, and the detection of
narrow absorption features. This leads to a complete understanding of the density, temperature, abundance, magnetic, and
dynamic structure of astrophysical plasmas. However, the termination of the EUVE mission has left a gaping hole in spectral
coverage at crucial EUV wavelengths (approx)100-300(angstrom)), where hot (10(sup 5)-10(sup 8) K) plasmas radiate most
strongly and produce critical spectral diagnostics. CHIPS will fill this hole only partially as it is optimized for diffuse emission
and has only moderate resolution (R(approx) 150). For discrete sources, we have successfully flown a follow-on instrument
to the EUVE spectrometer (A(sub eff)(approx) 1 cm(sup 2), R(approx) 400), the high-resolution spectrometer J-PEX(A(sub
eff)(approx) 3 cm(sup 2), R(approx) 3000). Here we build on the J-PEX prototype and present a strawman design for an
orbiting spectroscopic observatory, APEX, a SMEX-class instrument containing a suite of 8 spectrometers that together
achieve both high effective area (A(sub eff)> 20 cm(sup 2)) and high spectral resolution (R(approx) 10,000) over the range
100-300(angstrom). We also discuss alternate configurations for shorter and longer wavelengths.