Madrid2007

1
Milky Way
X-ray observations of Galaxies
NGC 4038/9
M 83
G. Fabbiano CfA
NGC 4365
2

• Red- Fe
• Green Mg
• Blue - Si
• Antennae
• Baldi et al 2006

Ne
Physics
Fe
Si
Mg
M 83 Soria Wu 2002
?

• Plasmas
• Accretion processes
• Extreme matter
• BH

M82 ULX

• Metal enrichment
• Outflows
• XRB models
• ULXs
• AGN models

• XRB SNR populations
• Active nuclei
• Hot ISM

M82
Astrophysics
Astronomy
NGC 4038/9 Fabbiano et al 2004

• Galaxy evolution
• AGN evolution
• AGN-galaxy feedback
• SN-ISM feedback
• Chemical evolution

NGC4636 Jones et al 2002
M81 Tennant et al 2001
NGC6240 Komossa et al 2003
Cosmology
3

• Example 1
• Poor spatial resolution resulting
• in low metallicity hot ISM
• Antennae ASCA vs Chandra
• Fornax A, ASCA vs Chandra

Example 4 Sub-arcsecond resolution and long
exposures needed to study the entire spectrum
of SMBH emission galaxy-AGN interaction
Galaxies are complex and relatively faint in
X-rays High resolution Long exposures
needed to Understand nearby galaxies and then
unravel the deep sky

• Example 2
• Poor spatial resolution resulting
• in spurious extended hot ISM,
• and wrong mass measurements
• E and S0 galaxies, pre-Chandra

Example 5 Sub-arcsecond resolution and long
exposures needed to study XRB populations
Example 3 Poor spatial resolution resulting in
the debate on the contribution of LMXBs to the
emission of E and S0 galaxies
4
NGC 821 high resolution long exposures

• Isolated E galaxy with old stellar population
• D24 Mpc
• Nuclear SMBH - inactive
• MSMBH 8.7 ? 107 M?
• LEdd 1 ?1046 erg/s

• First observed with Chandra in 2002 (39ks,
  Fabbiano et al 2004)
• 11 sources (LX gt 1.2?1038 erg/s)
• Fuzzy, S-shaped central emission
• Nuclear emission?
• Hot ISM to fuel the SMBH?

5

• 230 ks - Pellegrini et al 2007a, b
• 41 sources within D25
• LX gt 3?1037 erg/s

See poster!

• X-ray colors consistent with LMXB spectra

• LMXBs, stellar light, diffuse X-ray emission
  follow each other closely
• Cleaned diffuse emission spectrum consistent with
  LMXBs
• Diffuse X-ray emission dominated by (or totally
  due to) LMXBs

LMXB XLF
Bkg AGN
6
How do LMXBs form? - Debated since 1975
High-resolution imaging, sensitive,
time-monitoring

• Formation in GCs (efficient two-body encounters
  Clark 1975, Fabian et al 1975)?
• Ultra-compact NS-WD binaries (Bildsten Deloye
  2004)
• White dwarf orbiting NS
• 5-10 min orbit
• Short lifetime 107
• Transient at the LX ? 1037 erg s-1
• LX lt 2 ?1038 erg s-1
• High luminosity BH binaries(Kalogera, King
  Rasio 2004)
• Should be rare
• Possibly persistent (if from capture)

• Evolution of native field binaries (see Verbunt
  van den Heuvel 1995)?(Piro Bildsten 2002, King
  2002, Ivanova Kalogera 2006)
• E.g. semi-detached binaries with large unstable
  disks and giant donors
• Recurrent transients (recurrence time gt100yr,
  outburst 1-100 yr)
• Transients 1 4 candidates detected in
  NGC5128 ( Kraft et al 2001)

Question Do all form in GC then disperse in the
Field (J. Grindlay)?
Light-curves, XLFs
7
Marat Gilfanov has told us that LX(LMXBs)Mbut

• It also depends on the GC content of a
  galaxy(Kim Fabbiano 2004)

8
NGC 3379 - Deep Chandra ACIS Monitoring
Texp337 ks D 10.6 Mpc LB 1.3 ?1010 L?

• N. Brassington, D.-W. Kim, A. Zezas - CfA
• L. Angelini - GSFC
• R. Davies - Oxford
• J. Gallagher - Wisconsin
• V. Kalogera, T. Fragos - Northwestern
• King - Leicester
• S. Pellegrini - Bologna
• G. Trinchieri - Milano, Brera
• S. Zepf, A. Kundu - Michigan

• Little hot gaseous emission, to optimize faint
  LMXB detection

9
NGC 3379 - Field LMXB variability

• Comparing the 5 observations, 65 of (132
  detected) sources are variable
• Different types of long-term variability
  observed, both in flux and spectrum

Variable
10
NGC 3379 - Transients

• Luminous field LMXB are expected to be transients
  
• 15/98 sources (D25) are field candidate
  transients ( 3 in GCs)
• 4 on 6 months flares (detected in 1 or two
  consecutive times)
• 2 on for gt 5 years
• 7 on for gt 2 days
• 2 on for gt 4 months
• Persistent sources could be transients with
  on-time gt5yr

2001
2005
2006
2002
2003
2004
gt 15 of LMXBs are transient
11
Low luminosity Field and GC LMXB XLFs

• The high luminosity XLFs of GC and Field LMXBs
  are the same (Kim E. et al 2006)
• Consistent with (but not proving) similar origin
• Does this similarity extends to lower
  luminosities?

---GC-LMXBs ---field-LMXBs
1038
12
Low luminosity Field and GC LMXB XLFs
LMXB-Field
LMXB-Field
M31
NGC 3379 KS test P 0.2
LMXB in WFPC2 field
LMXB-GC
KMZ 2007

• XLFs of GC-LMXB and field-LMXB appear to differ
  below 1037 erg s-1
• There is a relative lack of GC-LMXBs
• Similar to M31 (Voss Gilfanov 2007)

expected
GC-LMXB
detected
30 ks, LX 2?1037
337 ks, LX 2?1036
LMXB-GC
13
Why do Field and GC XLFs differ at low LX?

• Do we detect multiple LMXBs in a given GC at the
  high LX end?
• This may artificially deplete the low luminosity
  XLF
• NO - variability demonstrates these are single
  luminous sources
• Are GC BH LMXBs persistent capture
  binaries?(Kalogera, King Rasio 2004)
• Sources with LXgt1038 erg s-1 vary, but are
  persistent

Different evolution for GC and Field LMXBs and
possibly for high and low luminosity GC LMXBs

• Are low luminosity (lt1037 erg s-1) LMXB-GC
  transient ultracompact binaries ?(Bildsten and
  Deloye 2004)
• Two transients just above 1037 erg s-1

14
LMXB formation by capture in the inner bulge?

• Voss and Gilfanov (2007) find an excess of LMXBs
  in the central arcminute of M31 over the number
  expected given the stellar light distribution
• Radial distribution follows ?2 consistent with
  2-body capture
• We find central LMXB excess also in NGC3379

NGC3379
M31
D25
A third formation path for LMXBs
15
ROSAT 5
16
From Chandra to Generation-XHigh angular
resolution Complementary to the Con-X / XEUS
view
Chandra 0.5 arcsec
Gen-X 0.1 arcsec
Active X-ray Optics
17
230 ks - Pellegrini et al 2007a, bAstrometry,
Chandra Hubble, using GC sources

• S1, S2, S4 are not point-like
• S2 is at the nucleus
• LX6?1038 erg/s
• Point-like AGN
• LXlt2.8?1038 erg/s (0.3-8 keV)
• LX/LEddlt2.5?10-8
• Hard emission?1.5, NHNHGal.

18
Is there hot ISM to feed the SMBH?

• LMXBs, stellar light, diffuse X-ray emission
  follow each other closely
• Cleaned diffuse emission spectrum consistent with
  LMXBs
• Diffuse X-ray emission dominated by (or totally
  due to) LMXBs

Stellar light
Nucleus fed by cold ISM Stellar outgassing