Xray study of a nearby nuclear

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
(No Transcript)
6
(No Transcript)
7
10 arcsec
8
galactic nucleus
X-ray binary
Super-soft source
SNR?
Wind / XRB?
9
ULX
X-ray pulsar
10
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
11
Diffuse emission from the starburst nuclear
region of M83 (multi-temperature thermal plasma
fit, T 0.3--0.8 keV)
12
Identification of the X-ray sources
multiwavelength comparisons
Chandra/ACIS
HST/WFPC2
13
HST/WFPC2 greyscale, Chandra contours
14
Ha greyscale (SSO), Chandra contours (0.3--8 keV)
15
V-band greyscale (VLT), 6 cm radio contours (VLA)
16
Cumulative luminosity distribution of the
discrete X-ray sources in a galaxy
1040
1038
1036
N(gtL)
erg/s
Starburst/star-forming regions
normal spiral population
Ellipticals
L
17
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 stars
  distance indicator
• ageing of the X-ray binary population (Wu 2001)

galactic history indicator
18
Colour-colour plot for bright M83 sources
19
X-ray binaries (BH, NS)
Soft sources (SNR )
Supersoft sources
20
Candidate X-ray SNR are associated to
brighter HII regions
Ha
21
Ha greyscale (SSO), Chandra point sources
22
6 cm radio greyscale (VLA), Chandra point sources
23
many SNR in M83, fewer in M81
24
M81 composite image UV (XMM
Optical Monitor) X-rays (XMM EPIC)
25
M81s active nucleus simple power-law fit (G
1.9)
L (2-10 keV) 1.5 1040 erg/s
26
M81s active nucleus power-law (G 1.9) Fe
lines
L (2-10 keV) 1.5 1040 erg/s
27
Hot Fe (XXVI) 6.96 keV
Cold Fe (I-XVI) 6.4 keV
Warm Fe (XVII-XXV) 6.7 keV
28
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? Interact
ion 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?
29
L (0.3-2 keV) 1.5 1040 erg/s
M81s soft X-ray spectrum (XMM RGS)
30
O VII emission
forbidden
resonance
31
Luminosity from hot gas component 5 1038 erg/s
(only 5 of total)
Hot gas temperature 0.20.7 keV
Hot gas is collisionally ionised, NOT photoionised
Ionising source Type Ia SNe in low-density medium
forbidden
resonance
32
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
33
M82
Lancon et al, in prep