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

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

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

10 arcsec

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

ULX X-ray pulsar

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

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

Identification of the X-ray sources: multiwavelength comparisons Chandra/ACISHST/WFPC2

HST/WFPC2 greyscale, Chandra contours

H  greyscale (SSO), Chandra contours ( keV)

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

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

Breaks in the luminosity distribution Luminosity functions in M83Luminosity functions in M81 Breaks/features in the luminosity function may depend on:  Eddington limit for the neutron stars distance indicator  ageing of the X-ray binary population (Wu 2001) galactic history indicator outside disk starburst nucleus

Colour-colour plot for bright M83 sources

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

Candidate X-ray SNR are associated to brighter HII regions HHHH

H  greyscale (SSO), Chandra point sources

6 cm radio greyscale (VLA), Chandra point sources

many SNR in M83, fewer in M81

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

M81’s active nucleus: simple power-law fit (  = 1.9) L (2-10 keV) = erg/s

M81’s active nucleus: power-law (  = 1.9) + Fe lines L (2-10 keV) = erg/s

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

Three narrow components of the Fe K  line 6.4 keV Fluorescent emission due to cosmic-ray electrons hitting cold (molecular) gas Milky Way keV From faint X-ray binaries? Interaction of non-thermal electrons with hot ( keV) gas? 6.4 keV Fluorescent emission due to cosmic-ray electrons hitting cold (molecular) gas M keV Interaction of non-thermal electrons with hot ( keV) gas? X-ray photoionised gas? From faint X-ray binaries?

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

O VII emission resonance forbidden

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

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 (10 7 yrs) Core-collapse SN remnants & high-mass X-ray binaries Diffuse emission in M81 probes older activity (10 9 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 keV Fe line emission in M81

Lancon et al, in prep M82