X-ray Diagnostics of Astrophysical Plasmas A (highly) biased summary XDAP/ Cambridge, MA, November 2004
Rather than a summary, identify trends and directions: Rapid progress in 5 years since launch of Chandra and XMM-Newton Progress now ‘problem-driven’, with priorities suggested by specific astrophysical problems High-resolution X-ray spectroscopy now applied to wide variety of sources and problems (‘up the ladder’) Next up: the Fe K shell!
XDAP/ Cambridge, MA, November 2004 1. Rapid Progress Capella Chandra HETGS/ Canizares et al. 2000 character of the field changed dramatically 1999/2000 much ‘handwringing’ unjustified in retrospect early benchmarks in stellar astrophysics invaluable some of the most spectacular recent Chandra/XMM results are spectroscopic-fact deserves far wider audience Starts to look like terrestrial lab data!
XDAP/ Cambridge, MA, November 2004 2. Progress now ‘problem-driven’, with priorities suggested by specific astrophysical problems helps simplify the choices one faces in modeling (John R., Francis R.): volume or quality? should start suggesting specific features to observe in specific sources, for specific effects! examples: Time-dependent ionization balance in SNR; connection with physics of explosion and NS birth event (Martin L., Cas A) Fe XVII 15.01/15.26 A ratio; radiative transfer? O innershell absorption spectrum: AGN warm absorbers; ISM/IGM?
3. High-resolution X-ray spectroscopy now applied to wide variety of sources and problems (‘up the ladder’) discrete emission from GRB afterglows GRB 011211 Reeves et al., 2002 Swift goes today! (but careful with CCD spectroscopy! Only unblended unique signature of CX-XPN is S XVI RRC!! Cf. Liedahl 1993)
XDAP/ Cambridge, MA, November 2004 X-ray absorption signature of astrophysical dust/ X-ray spectroscopy of neutrals, molecules Cf. Julia L’s presentation on XAFS spectroscopy; Jon Woo et al., 1998
XDAP/ Cambridge, MA, November 2004 Also, physics of electron impact X-ray fluorescence sources used for calibration…the Chemical Shift, etc…. Mg K with LETGS(m=5), HETGS/MEG(m=3), HETGS/HEG(m=2) (cf. Dan Dewey’s HETGS page at MIT)
XDAP/ Cambridge, MA, November 2004 Absorption line spectroscopy: ISM, IGM Cf. Yangsen Y’s, Daniel W.’s poster and talk: Absorption by highly ionized species in the Galaxy and its halo (?). Prospects for detection of emission? McCammon et al. 2002
XDAP/ Cambridge, MA, November 2004 Absorption line spectroscopy: ISM, IGM Radiative transfer effects! Scattering of the unresolved XRB off He-like O resonance may contribute major fraction to IGM emission! (Also (different context): Duane L’s talk on efficiency of Resonant Auger Destruction- touches on several aspects of the meeting topic)
XDAP/ Cambridge, MA, November 2004 Amazingly, this subject now has connections with Heliospheric physics!! CE emission from highly ionized O in comets, geocorona: very local diffuse foreground! Cf. Talk by Dennis B., paper by Brad W. et al. 2004 It pays to read each other’s papers! The innovative aspect of our work deserves FAR wider familiarity among astronomers; strategically important to spread these stories (Constellation X, XEUS, …) (*) (*) also: Lab Astrophysics
XDAP/ Cambridge, MA, November 2004 4. Next Up: Fe K Band!! Seven talks on this topic alone at the meeting; Representative/suggestive spectra already taken at Astro-E2 XRS resolution (EBIT/LLNL): Next year at this time we will be looking at similar spectra from cosmic sources! If the spectroscopy with the diffraction grating Spectrometers on Chandra and XMM-Newton is any guide: we will probably figure out ‘how to diagonalize the (spectroscopic) matrix’ (Claude Canizares, summarizing the first ASCA conference in Tokyo), making X-ray spectroscopy of cosmic sources even more indispensable to astrophysics
XDAP/ Cambridge, MA, November 2004 Excellent meeting- apologies to everyone whose work I did not mention; many thanks to the organizers the sponsors, and Randall in particular!