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Hot G as in Nearby G ala xies

Hot G as in Nearby G ala xies. Li Jiangtao Astronomy Department of Nanjing University Department of Astronomy, UMASS. Co-workers. Q. Daniel Wang (UMASS) Yang Chen (NJU) Zhiyuan Li (UMASS) Shikui Tang (UMASS) Bing Jiang (NJU) Li Ji (MIT) Yangsen Yao (U Colorado)

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Hot G as in Nearby G ala xies

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  1. Hot Gas in Nearby Galaxies Li Jiangtao Astronomy Department of Nanjing University Department of Astronomy, UMASS

  2. Co-workers • Q. Daniel Wang (UMASS) • Yang Chen (NJU) • Zhiyuan Li (UMASS) • Shikui Tang (UMASS) • Bing Jiang (NJU) • Li Ji (MIT) • Yangsen Yao (U Colorado) • Judith A. Irwin (Queen’s University) • Joern Rossa (U Florida)

  3. Outline • X-ray emitting mechanism • Galactic feedback • Basic problems in early-type galaxies • Hot gas in normal galaxies (Milky Way, M 31, NGC 5866, NGC 5775) • Summary

  4. X-ray emitting mechanism • Magnetic energy • Gravitational energy • Shock: In galaxies, since the specific energy of shock heating is highest, it is the dominate process.

  5. Centaurus A Galactic feedback Star formation AGN SNe Ia M82 Sombrero

  6. In early type galaxies • Over cooling problem: Structure formation simulation predicted cooled gas is 2 or 3 times larger than observed in galaxies. • Missing energy problem: The expected mechanical energy feedback is much larger than observed in X-ray emission. • Missing gas problem: In S0 galaxies, observed gas mass only account for ~10% of the stellar evolution mass return. Tang et al.

  7. Hot gas in normal galaxies: our Galaxy X-ray binary AGN Wang et al. 05, Yao & Wang 05/06, Yao et al. 06/07 ROSAT all-sky survey in the ¾-keV band X-ray binary

  8. Soft X-ray and UV absorption line: evidence for interaction between hot/cold gas Yao & Wang 2006, Yao et al. 2006

  9. M 31 IRAC 8 micro K-band 0.5-2 keV Missing energy problem. Mass loss, evaporation plays an important role. Ionizing source for 10^4 K gas, evolved stars are the most important source. Li & Wang 2007 0.5-1 keV 1-2 keV 2-8 keV Lx~2x1038 erg/s Zh=0.6 kpc, but with flat tails at large z

  10. Further evidence for interaction between cold/hot gas in S0 galaxies: (NGC 5866) Li, Wang & Li2008

  11. Feedback in disk-wide star forming galaxies:NGC 5775 • Hot gas heating efficiency by SF is not much different from starburst galaxies. • At least two components of diffuse hot gas: • (1) Near disk with more mass-loading, heated by disk star forming regions, lower temperature. • (2) In the bulge with little mass-loading, heated mainly by SNe Ia, higher temperature. Li et al. 2008

  12. Summary • Diffuse hot gas in non-starburst, non-AGN galaxy halos: • Temperature: ~0.3 keV, larger than gravitational energy, smaller than SNe specific energy. Sometimes there is a second component with higher temperature. • Luminosity: 10^38-10^40 erg/s, much smaller compared with AGN. • Mass: 10^7-10^9 M_solar • Over cooling problem: Structure formation simulation predicted cooled gas is 2 or 3 times larger than observed in galaxies. • Missing energy problem: The expected mechanical energy feedback is much larger than observed in X-ray emission. • Missing gas problem: In S0 galaxies, observed gas mass only account for ~10% of the stellar evolution mass return. • Solution of these problems: SNe heating and mass loss (in large galaxies, AGN feedback may be more important).

  13. Thank you!

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