Hot Gas and Outflows of Nearby Normal Galaxies

Q. Daniel Wang (UMass)

• Most of present galaxies are not nuclear starbursters

• Phenomena that would be otherwise overwhelmed– Disk/halo interaction– Bulge wind driven by Type Ia SNe– Accretion from the IGM

Subtle, but enduring strongly affect the evolution of galaxies

ROSAT all-sky survey (3/4-keV band)

Absorption Sight Lines

No detection X-ray binaryAGN

Yao & Wang 2005

Wang et al. 2005

Ionization fraction

Assuming CIE and solar abundances

OVI

OVIIIOVII

Ne IX

Ne VIII

Ne IX

Also detection of OVII K,

K,and OVIII K linesMean T ~ 106.3+/-0.2 KnH~3.4x10-3 cm-3

(assuming filling factor =1)

Ne IX K absorption lines in LMXB

spectra

Hot gas disk model

nH = 5.0(-1.8,+2.6)x10-3 cm-3exp[-|z|/1.2(-0.5,+0.7) kpc]

Total NH~1.6 x1019 cm-2

X-ray absorption is primarily around the Galactic disk within a few kpc!

MRK 421

Mkn 421 3C 273

LETG/ACIS

LETG/HRC

Differential X-ray absorption line spectroscopy

Depth:

NH =n d

=(3-11) x1019 cm-2

n2 d ~ 2x10-2 cm-6 pc

d ~ 5 kpc

Doppler broadening:

b=31-46 km/s

for Mrk 421

b=120 (80-204) km/s

for 3C 273

Wang & Yao 2005

Summary: Galactic hot gas disk

•Vertical scale ~ 1-3 kpc•Mean temperature ~ 106.2 K•density ~ 3 x 10-3 cm-3

•Metal abundance ~ solar

NGC 3556: optical vs. X-ray

Red – optical

Green – 0.3-1.5 keV band

Blue – 1.5-7 keV band

NGC 3556: radio vs. X-ray

Wang et al. 2003

Sb galaxy NGC 4565

William McLaughlin (ARGO Cooperative Observatory)

Red – optical

Green – 0.3-1.5 keV band

Blue – 1.5-7 keV band

Wang (2004)

Very low specific SFR

No sign for any outflows from the disk in radio and optical

No correlation with radio!

•Lx ~ 3 x 1039 erg/s

NGC 4594: X-ray vs. optical

ACIS-S 0.3-1.5 keV intensity contours

Diffuse 0.3-1.5 keV intensity contours

H ring

NGC 4594:X-ray

spectraPoint source

Inner bulge

Outer bulge

disk

•Average T ~ 6 x 106 K

•Slight softening in the disk and in the outer bulge

•Strong Fe –L complex

•Lx ~ 4 x 1039 erg/s NGC 4631

Missing stellar feedback in early-type disk galaxies

• For NGC 4594, hot gas radiative cooling rate ~ 2% of LSN ~ 2.4 x 1041 ergs/s from Type Ia SNe alone

• Not much cool gas to hide or convert the SN energy

• Mass and metals are also missing!– Mass input rate of evolved stars

~ 1.3 Msun/yr– Each Type Ia SN 0.7 Msun Fe

Gone with the wind!

Bulge wind model

• Spherical, steady, and adiabatic • NFW Dark matter halo + stellar bulge• Energy and mass input follows the

stellar light distribution• CIE plasma emission• Implemented in XSPEC for both

projected spectral and radial surface brightness analyses

Li & Wang 2004

Data vs model

Consistent with the expected total mass loss and SN rates as well as the Fe abundance of ~ 4 x solar!

The best-fit model density and temperature profiles of the bulge

wind

Outflow-inflow interaction

NGC 3379: ram-pressure confined galactic wind?

Conclusion

• At least two components of diffuse hot gas:– Disk – driven by massive star formation– Bulge – heated primarily by Type-Ia SNe

• There is so far little evidence for X-ray emission or absorption from IGM accretion halos. But there are indications from the interaction with other gaseous components.