NGC3379 T exp =337ks NGC4278 T exp =470ks D=10.6MpcL B =1.3 - PowerPoint PPT Presentation

Black
Hole
Binaries
in
Ellip0cal
Galaxies Results
of
the
 Chandra 
deep
monitoring
observa0ons
of
NGC
3379
and NGC
4278 G.
Fabbiano Harvard‐Smithsonian
CfA NGC
3379 
 T exp =337ks 
 NGC
4278
 T exp =470ks D=
10.6
Mpc
L B 
=
1.3
 × 10 10 
L  
 D=16.1
Mpc
L B 
=
1.6 × 10 10 
L  GC poor 
 GC rich

Galac0c
BHBs
and
their
spectral
states Remillard
&
McClintock
2006

Do
we
see
similar
spectral
states
in extragalac0c
LMXBs
as
in
Galac0c
BHBs? NGC
3379
–
Brassington
et
al
2010
(submiXed) NGC
4278
–
Fabbiano
et
al
2010
(submiXed) Nicky Brassington

‘Biases’
in
spectral
results Brassington
et
al
2010 Galac0c
BHB
spectra
are
typically
well
represented
with
2 • components,
with
varying
flux
ra0o:
power‐law

and
accre0on
disk The
sta0s0cs
of
LMXB
detec0ons
do
not
give
us
enough
counts
to • aXempt
a
two
component
spectral
fit What
can
we
learn
from
the
results
of
fi`ng
these
data
with
single • component?
Either
power‐law
or
DBB? We
ran
extensive
simula0ons
that
show
we
can
learn
from
these • simple
fit
results 1. MCD
+PO
simulated
spectra 2. kT
range:
0.5
–
2.25
keV
in
steps
of
0.25
keV 3. Γ
range:
1.5
‐2.3
in
steps
of
0.2 4. Flux
ra0os
of
two
components
range:
0%
‐
100% 5. Spectra
simulated
with
1000
(and
500)
counts 6. 100
spectra
generated
for
each
combina0on
of
parameters

‘Biases’
in
spectral
results 
N H 
vs.
Disk/total
in
Power‐law
only
fit Brassington
et
al
2010 Effect
of
fi`ng
a
power‐ law+
disk
spectrum
with no
intrinsic
N H 
(only Galac0c)
with
a
single power‐law
model solid
lines,
Γ=1.7 Best
fit
N H 
>
N H 
Gal. Greater
‘apparent
‘
N H for
increasingly
greater disk
components N H 
Gal.

‘Biases’
in
spectral
results
–
N H 
vs.
PO/total
in
Disk
only
fit Brassington
et
al
2010 Effect
of
fi`ng
a
power‐ law+
disk
spectrum
with N H 
Gal. no
intrinsic
N H 
(only Galac0c)
with
a
single ‘Disk’
model Best
fit
N H 
<
N H 
Gal. If
spectrum
includes
a PO
component Similar
dependence
for a
range
of 
kT in
 ~0.5
–
2.2
keV

The
simula0ons
show
that
fi`ng
a
disk
+
power‐law
spectrum
with: 
 Single
power‐law































N H >N H 
Gal. Single
disk
(kT~
1‐2
KeV)


















N H <N H 
Gal. The
effect
is
stronger
for
larger
frac0on
of
second
component

NGC
3379
‐
examples
of
variable
BHB
Candidates Brassington
et
al
2010
‐
submiXed d l e i F ? G C

NGC
3379
–
S86
(Field) N H Gal Disk 2 σ 2+4 1+3 Power‐law

NGC
3379
–
S42
(GC) N H Gal 1+3 Disk 2 σ 2+4 Power‐law

NGC
3379
–
S102 cool
disk? N H Gal N H Gal

NGC
3379
–
S102

‐

cool
disk? T in 
‐N H T in 
‐
 Γ

BHB
Candidates
in
NGC
3379
&
NGC
4278 NGC
3379 Source
74 A
20
Msol
BH?

Spectra
of
LMXBs
in
NGC
4278 Lenta0
et
al.,
AAS;
Fabbiano
et
al
2010 • Squares
–
GC‐LMXBs
 Circles
–
Field‐LMXBs
(see
Brassington
et
al
2009) • Red
‐
>
1
x
10 38 
erg/s



Yellow
–
1x10 37 
‐1x
10 38 
erg/s

Comparison
of
‘average’
Field
LMXB
spectra L X 
>
1.5×10 38 
erg
s ‐1 
spectrum
is
Disk
dominated L X 
<
1.5×10 38 
erg
s ‐1 
spectrum
is
Power‐Law
dominated Power‐law
fits Disk
fits Γ kT in N H Gal N H N H

Comparison
of
‘average’
GC
and
Field
BHB
Candidate
spectra GC Power‐law
fits Disk
fits kT in Γ FIELD GC High
Lx
GC N H Gal N H N H • High
luminosity
field
and
GC
spectra
are
consistent
with
each
other • Low‐luminosity
(<6
10 37
 erg/s)
GC
spectra
are
either
more
absorbed power‐law
or
cooler
disks

Is
Ellip0cal ‘rejuvena0on’ linked
with
BHB produc0on? ‘young’ (Kim
&
Fabbiano ‘young’ ‘old’ 2010,
ApJ submiXed) Frac0on
of
LMXBs
with L X >5x10 38 
erg/s ‘old’

Summary • Luminous
LMXBs
in
Ellip0cal
Galaxies
behave
like
BHBs • In
the
cases
where
the
spectrum
appears
disk‐dominated • 
most
sources
are
consistent
with
the
L X 
‐

T in 
rela0on
of 5‐10
M  
BHs • 
there
is
one
case
sugges0ng
a
20
M  
BH • 
there
is
one
case
of
cool
disk
–
ouxlow? Comptoniza0on?
Big
BH? • We
find
differences
in
the
spectra
of
Field
and
GC
LMXBs with
L X 
<
6x10 37 
erg/s • Galaxy
‘rejuvena0on’
is
correlated
with
an
increased frac0on
of
luminous
BHBs
(>
5x10 58 
erg/s)

What
is
this?
….
Not
the
eye
of
Sauron A
free
drink
for
the
first
right
answer See
Junfeng
Wang

Luminous
LMXBs
in
NGC
3379 How
do
they
compare
with
Galac0c
BHB? Source
74 A
20
Msol
BH?

Summary • Luminous
LMXBs
in
Ellip0cal
Galaxies
behave
like
BHBs • In
the
cases
where
the
spectrum
appears
disk‐dominated • 
most
sources
are
consistent
with
the
L X 
‐

T in 
rela0on
of
5‐10
M  BHs • 
there
is
one
case
sugges0ng
a
20
M  
BH • 
there
is
one
case
of
cool
disk
–
ouxlow?
Comptoniza0on?
Big
BH? • We
find
differences
in
the
spectra
of
Field
and
GC
LMXBs
with
L X 
< 6x10 37 
erg/s