IRAC 8 microK-band0.5-2 keV

X-ray Emission Line Spectroscopy of Diffuse Hot

Plasma

XMM-Newton RGSLiu, Wang, Li, & Peterson 2010

Li & Wan 2007

T ~ 3 x 106 K

Lx~2x1038 erg/s

Chandra ACIS-I

X-ray spectroscopy: He-like ions• R (or W): Resonance

line (allowed) 1s2p 1P11s2 1S0 electronic dipole

transition • I (or x+y):

Intercombination line 1s2p 3P1 1s2 1S0 (y) 1s2p 3P2 1s2 1S0 (x) Triple or quadruplet • F (or z): Forbidden

line 1s2s 3S1 1s2 1S0

relativistic magnetic dipole transition (Aji

very low)

Simplified Grotrian diagram

Porquet & Dubau (2000)

RI

F

Photo-ionized plasma as seen in an AGN can have stronger forbidden lines.

Solar Wind Charge Exchange

From Dennerl 2010

Solar Wind Charge Exchange

• Charge exchange (CX) nature of comet X-ray emission is confirmed, spectroscopically and temporally.

• CX has a cross-section of ~10-15 cm-2

• PCX/Pth propto 1/ne2 on scales of

mean free path

Peter Beiersdorfer

CX is also expected at the heliosphere

Much of the diffuse soft X-ray background may arise from the CX!

ROSAT all-sky survey in the ¾-keV

bandX-ray binaryAGN Futamoto et al. 2004, Wang et al. 05,

Yao & Wang 05/06, Yao et al. 06/07/08

4U1957+11

X-ray absorption line spectroscopy of diffuse hot plasma

Fe XVII K

• Tracing all K transitions of metals all three phases of the ISM.

• Not affected by photo-electric absorption unbiased measurements of the global ISM.

Yao & Wang 2006, Yao et al. 2006, Futamoto et al 2004

LETG+HETG spectrum of LMXB 1820-303

Chandra ACIS observations of nearby galaxies

Soria & Wu (2002) (Credit: NASA/CXC/SAO/R.DiStefano et al.)

XMM-Newton RGS spectrum of the nuclear starburst region of M51

Charge exchange may be responsible for much of diffuse soft X-ray emission in both normal and starburst galaxies.

Similar CX signatures are also observed in starburst galaxies

Soft X-ray arises primarily from the interplay between a superwind and entrained cool gas clouds.

Composite of optical (HST), infrared (Spitzer), and X-ray (Chandra) images

Li, Mao, Wang 2011

XMM-Newton Reflection Grating Spectrometers

Spatially-resolved X-ray spectroscopy

OVIII contours on HST image

OVIII contours on OVII image

NGC 4438 in the Virgo Cluster

Ha+[NII] image (Kenney et al. 1995). Chandra 0.3-2 keV image, Machacek et al. 2004

Operating X-ray Telescopes

SWIFT

Chandra

Suzaku

XMM-Newton

Future X-ray telescopes

Astro-H, planned for launch in 2013

eROSITA 2012

Athena???

Summary• X-ray spectroscopy is the future of the X-

ray astronomy X-ray astrophysics, providing key diagnostics of plasma in the Universe.

• Much of the diffuse X-ray emission from galaxies may arise from the charge exchange.

• A lot can already be done to understand the process, which traces the galactic feedback and the presence of cool gas, especially in low density environments.