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
Texp=337ks
 NGC
4278
Texp=470ks

D=
10.6
Mpc
LB
=
1.3
×1010
L
 D=16.1
Mpc
LB
=
1.6×1010
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

• 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

‘Biases’
in
spectral
results

Brassington
et
al
2010 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

Effect
of
fi`ng
a
power‐ law+
disk
spectrum
with no
intrinsic
NH
(only Galac0c)
with
a
single power‐law
model solid
lines,
Γ=1.7 Best
fit
NH
>
NH
Gal. Greater
‘apparent
‘
NH for
increasingly
greater disk
components

‘Biases’
in
spectral
results 
NH
vs.
Disk/total
in
Power‐law
only
fit Brassington
et
al
2010

NH
Gal.

Effect
of
fi`ng
a
power‐ law+
disk
spectrum
with no
intrinsic
NH
(only Galac0c)
with
a
single ‘Disk’
model Best
fit
NH
<
NH
Gal. If
spectrum
includes
a PO
component Similar
dependence
for a
range
of 
kTin
~0.5
–
2.2
keV

‘Biases’
in
spectral
results
–
NH
vs.
PO/total
in
Disk
only
fit Brassington
et
al
2010

NH
Gal.

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































NH>NH
Gal. Single
disk
(kT~
1‐2
KeV)


















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

NGC
3379
‐
examples
of
variable
BHB
Candidates

Brassington
et
al
2010
‐
submiXed

G C F i e l d ?

NGC
3379
–
S86
(Field)

1+3 2+4 NHGal 2σ Power‐law Disk

NGC
3379
–
S42
(GC)

1+3 2+4 NHGal 2σ Power‐law Disk

NGC
3379
–
S102 cool
disk?

NHGal NHGal

Tin
‐NH Tin
‐
Γ

NGC
3379
–
S102

‐

cool
disk?

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
1038
erg/s



Yellow
–
1x1037
‐1x
1038
erg/s

Power‐law
fits Disk
fits NH NH

NHGal

Comparison
of
‘average’
Field
LMXB
spectra

LX
>
1.5×1038
erg
s‐1
spectrum
is
Disk
dominated LX
<
1.5×1038
erg
s‐1
spectrum
is
Power‐Law
dominated

Γ kTin

GC FIELD Power‐law
fits Disk
fits Γ NH NH kTin

GC

NH

Gal

Comparison
of
‘average’
GC
and
Field
BHB
Candidate
spectra

High
Lx
GC

• High
luminosity
field
and
GC
spectra
are
consistent
with
each
other
• Low‐luminosity
(<6
1037
erg/s)
GC
spectra
are
either
more
absorbed

power‐law
or
cooler
disks

Frac0on
of
LMXBs
with LX>5x1038
erg/s

‘young’ ‘old’

Is
Ellip0cal ‘rejuvena0on’ linked
with
BHB produc0on? (Kim
&
Fabbiano 2010,
ApJ submiXed)

‘young’ ‘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
LX
‐

Tin
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
LX
<
6x1037
erg/s

• Galaxy
‘rejuvena0on’
is
correlated
with
an
increased

frac0on
of
luminous
BHBs
(>
5x1058
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
LX
‐

Tin
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
LX
<

6x1037
erg/s