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X-ray study of a nearby nuclear starburst and a nearby AGN

X-ray study of a nearby nuclear starburst and a nearby AGN. Roberto Soria ( UCL) Mat Page, Kinwah Wu, Alice Breeveld, Silvia Zane. Contents. M83 (grand-design spiral with nuclear starburst) diffuse emission discrete source populations

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X-ray study of a nearby nuclear starburst and a nearby AGN

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  1. X-ray study of a nearby nuclear starburst and a nearby AGN Roberto Soria (UCL) Mat Page, Kinwah Wu, Alice Breeveld, Silvia Zane

  2. Contents • M83 (grand-design spiral with nuclear starburst) diffuse emission discrete source populations multi-wavelength comparisons • M81 (grand-design spiral with active nucleus) discrete source populations origin of the X-ray emission lines comparison between Milky Way, M83, M81 For more details, see recent papers by our UCL group (Soria et al 2003, Page et al 2003, 2004)

  3. External triggers Internal triggers? Cold gas STAR FORMATION Stellar evolution PNe, SNe II, Ib/c Hot gas (shocks) Diffuse soft X-rays Compact remnants HMXB, LMXB X-rays from accretion

  4. A look in detail: M83 (d ~ 4 Mpc)

  5. 10 arcsec

  6. galactic nucleus X-ray binary Super-soft source SNR? Wind / XRB?

  7. ULX X-ray pulsar

  8. T ~ 0.6 keV Starburst nucleus High abund of Ne, Mg, Si,S Low Fe/O, Fe/C T ~ 0.4 keV ISM is enriched by winds from WR stars, core-collapse SNe Spiral arms 80% of X-ray luminosity is from diffuse hot gas

  9. Diffuse emission from the starburst nuclear region of M83 (multi-temperature thermal plasma fit, T~ 0.3--0.8 keV)

  10. Identification of the X-ray sources: multiwavelength comparisons Chandra/ACIS HST/WFPC2

  11. HST/WFPC2 greyscale, Chandra contours

  12. Ha greyscale (SSO), Chandra contours (0.3--8 keV)

  13. V-band greyscale (VLT), 6 cm radio contours (VLA)

  14. Cumulative luminosity distribution of the discrete X-ray sources in a galaxy 1036 1038 1040 N(>L) erg/s Starburst/star-forming regions “normal” spiral population Ellipticals L

  15. Breaks in the luminosity distribution Luminosity functions in M83 Luminosity functions in M81 outside disk outside disk starburst nucleus Breaks/features in the luminosity function may depend on: • Eddington limit for the neutron starsdistance indicator • ageing of the X-ray binary population(Wu 2001) galactic history indicator

  16. Colour-colour plot for bright M83 sources

  17. X-ray binaries (BH, NS) Soft sources (SNR +) Supersoft sources

  18. Candidate X-ray SNR are associated to brighter HII regions Ha

  19. Ha greyscale (SSO), Chandra point sources

  20. 6 cm radio greyscale (VLA), Chandra point sources

  21. many SNR in M83, fewer in M81

  22. M81 composite image UV (XMM Optical Monitor) + X-rays (XMM EPIC)

  23. M81’s active nucleus: simple power-law fit (G = 1.9) L (2-10 keV) = 1.5 1040 erg/s

  24. M81’s active nucleus: power-law (G = 1.9) + Fe lines L (2-10 keV) = 1.5 1040 erg/s

  25. Hot Fe (XXVI) 6.96 keV Cold Fe (I-XVI) 6.4 keV Warm Fe (XVII-XXV) 6.7 keV

  26. Three narrow components of the Fe Ka line Milky Way M81 6.4 keV Fluorescent emission due to cosmic-ray electrons hitting cold (molecular) gas 6.4 keV Fluorescent emission due to cosmic-ray electrons hitting cold (molecular) gas 6.7 + 6.9 keV From faint X-ray binaries? Interaction of non-thermal electrons with hot (0.2-0.5 keV) gas? 6.7 + 6.9 keV Interaction of non-thermal electrons with hot (0.2-0.5 keV) gas? X-ray photoionised gas? From faint X-ray binaries?

  27. L (0.3-2 keV) = 1.5 1040 erg/s M81’s soft X-ray spectrum (XMM RGS)

  28. O VII emission forbidden resonance

  29. Luminosity from hot gas component = 5 1038 erg/s (only 5% of total) Hot gas temperature = 0.2—0.7 keV Hot gas is collisionally ionised, NOT photoionised Ionising source: Type Ia SNe in low-density medium forbidden resonance

  30. Summary & work in progress X-ray study of a nearby starburst (M83) and AGN (M81) Relation between star-formation rate and hot gas temperature & density Diffuse emission probes recent starburst in M83 (107 yrs) Core-collapse SN remnants & high-mass X-ray binaries Diffuse emission in M81 probes older activity (109 yrs) Type Ia SN remnants & low-mass X-ray binaries Luminosity and colour distributions of discrete X-ray sources probe galactic star formation history Three components in 6.4-6.9 keV Fe line emission in M81

  31. M82 Lancon et al, in prep

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