Astrophysical sources of rays Isabelle Grenier University Paris - PowerPoint PPT Presentation

Astrophysical sources of γ rays Isabelle Grenier University Paris Diderot & CEA Saclay (with great help from the Fermi collaboration) TAUP Rome 05/07/09

the GeV sky Fermi
LAT
3
months:
205
bright
(<
10
σ)
sources 9
months,
>
200
MeV:
many
more

the TeV sky

γ -ray source physics accreDon
powered
 
 
 shock
powered
 
 
 
 inducDon
powered relaDvisDc
jets
 
 
 
 parDcle
acceleraDon
 
 relaDvisDc
winds 
 
 
 
 
 
 
 (non
exclusive)

credits Fermi
plots:
 • arxiv:
Fermi
collaboraDon,
Abdo
et
al.
 • hOp://www.nasa.gov/mission_pages/GLAST/main/index.html HESS
plots: • arxiv:
Aharonian
et
al. • hOp://www.mpi‐hd.mpg.de/hfm/HESS/

γ -ray bursts Fermi
look
into
fireballs from
keV
to
mulD‐GeV
energies 1000-2000 AU 1-6 AU X-rays prompt γ � 2 � ambient � 1 � medium > 100 MeV? Prompt � � 0.01-5 MeV optical 20 km Internal shocks Reverse shock r a d i Forward shock o fireball
expansion,
aYerglow
evoluDon,
X‐ray
flashes,
plateaux
…
and
GeV
puzzle

γ -ray bursts 7
long
+
2
short
GRB,
from
8
keV
to
tens
of
GeV short
&
long
GRB:
similar
phenomenology
at
high
energy
 short GRB081024B intense, z = 4.35, to 13 GeV long GRB090323 (200s) radio to GeV afterglow z = 3.6 ✴ long GRB080825C afterglow long GRB080916C short GRB090510 intense, z = 4.35, to 13 GeV intense, z = 0.9

high-energy γ -ray afterglows aYer
EGRET
findings GRB080825C,
the
1st
GBM+LAT
burst GeV
γ
rays:
 onset
delay,
hardening,
quick
decay suggesDve
of
aYerglow
emission
from
reverse
shock
(SSC
or
ExC) time → 8-260 keV 0.26-5 MeV > 80 MeV PRELIMINARY

prompt spectra & Γ min short
and
long
GRBs
so
far:
single
band
spectra
from
keV
to
GeV ⇒ 
synchrotron
dominates
to
late
Dmes no
quick
arrival
of
SSC
at
E
>
100
MeV
(blast
wave
not
cooled
so
quickly) no
evidence
for
γ GeV 
+
γ Band 
→
e ± 

absorpDon
or
soYening ⇒ 
Γ
≥
900

 
 
 
 
 
 
 
 
 
 Γ
≥
887
±
21 short long GRB081024B GRB080916C ⇒ 
light
jets

delayed & long-lasting prompt γ rays long
ex:
GRB080916C,
→
1400
s short
ex:
GRB081024B 8 keV – 260 keV 260 keV – 5 MeV LAT raw LAT > 100 MeV LAT > 1 GeV T 0

prompt GeV delay (sub‐MeV,
GeV)
Dme
correlaDon
 ⇒ 
closeby
sources

prompt GeV delay (sub‐MeV,
GeV)
Dme
correlaDon
 ⇒ 
closeby
sources ? r e t f o s r e d r a h

prompt GeV delay (sub‐MeV,
GeV)
Dme
correlaDon
 ⇒ 
closeby
sources γγ absorption?... no softening or cutoff no GeV when hard X still ↑

prompt GeV delay (sub‐MeV,
GeV)
Dme
correlaDon
 ⇒ 
closeby
sources p + acceleration time then p + synchrotron or cascade emission

prompt GeV delay (sub‐MeV,
GeV)
Dme
correlaDon
 ⇒ 
closeby
sources SSC GeV afterglow tail?… no double bump

AGN families FSRQ (low M BH , large L acc )? Seyfert I NLR Seyfert II FR II dust dust torus torus BLR FR I radio-quiet AGN Bl Lac (large M BH , low L acc )?

AGN families FSRQ (low M BH , large L acc )? Seyfert I NLR Seyfert II FR II BLR FR I torus torus dust dust radio-quiet AGN Bl Lac (large M BH , low L acc )?

γ -ray AGN TeV:
27
Bl
Lac
+
1
FSRQ
+
2
radiogalaxies
(M87
+
Cen
A) GeV:
42
Bl
Lac
+
58
FSRQ
+
4
uncertain
+
2
radiogalaxies
(NGC
1275
+
Cen
A)
+
...

radio-loud Seyfert in γ rays! PMN
J0948+0022
(Sey1
lines
+
narrow
lines
+
radio‐loud
variable
core,
z
=
0.58) δ
>
2.5
and
θ
<
22° Effelsberg OVRO Swift Fermi simultaneous low
M BH 
=
10 6‐8 
M ⊙ 
 but
high
L/L Edd 
=
0.4 BLR low‐power
FSRQ
like disc ExC ⇒ 
acDve
jet
 L BLR = 0.1 L disc any
other? torus corona

jet questions fast spine Γ = 1 → 15 10 16 m 10 15 m slow MHD turbulent C beam S S spine-sheath or Ė kin carried by e ± , p + ? γ radiation deccelerating flow? e + pattern? terminal shock γ e - B energy density? population IC vs. syn bump if soft stat. 100 G ? ExC targets known t e k c ? B equip in slow jet? o s r k c n o y o t h t i l p s i b m a o ? i r C r a a v f d w i p o n h a o r i t p ? λ + p - r γ i o t l s u b m a 0 ± π γ TeV cutoff (but EBL), other cutoffs... Doppler factor? γ from time scale & γγ R e ± L γ B which E max (e ± )?

blazar sequence external IC … SSC trend
for
fainter,
harder
blue
 blazars
(Bl
Lacs) spectral
hardening
confirmed FSRQ
→
LBL
→
IBL
→
HBL
 Bl Lac unknown radiogal Fermi: FSRQ Bl Lac unknown radiogal

a lot of variability... all‐sky
monitoring
every
3h:
 1/3
variable
Fermi‐LAT
sources,
mostly
off
the
plane only
33
former
EGRET
sources,
11
at
GeV
+
TeV
energies impressive
mulD‐λ
campaigns

… and a lot of confusion PKS
2155‐304
in
flare
state:
X‐TeV
Dght
correlaDon
(SSC) in
low
state:
SSC
3
zones ⇒ 
no
X‐TeV
correlaDon
expected,
none
seen,
unlike
in
flare
state ⇒ 
no
opt‐TeV
correlaDon
expected,
one
seen
 ⇒ 
not
synch.
seeds
 ⇒ 
“ExC” where
are
the
opDcal
electrons? ATOM Swift-RXTE Fermi HESS F opt - Γ GeV F opt -F TeV E e < 118 GeV F X -F TeV F X - Γ GeV E e < 7.2 GeV not same time sampling

intrinsic breaks? Δα
=
1.2
>
0.5
for
cooling FSRQ internal
jet
γγ
absorpDon
<< 200
eV
+
γ
→
e ± 
? inner
disc
targets,
r
<
10‐100
R grav BLR
re‐scaOered but
no
soY
X‐ray
cascade
signs… Y R A N I M I L impact
on
blazar
contribuDon
to
EBL E R P LBL HBL Y R A Y N R A I M N I L I M E R I L P E R P

NGC 1275 nearby
radiogalaxy
(alias
Perseus
A
or
3C84)
in
the
Perseus
cluster with
blazar‐like
radio
core piercing
jets radio CXO 0.025” 26 lyr NRAO

NGC 1275 variability
COS‐B,
EGRET,
Fermi
(also
radio)
 ⇒ 
AGN
source standard
red
blazar
SED,
L jet 
(1p + /e ‐radiaDng )
 ～ 
L kin (bubbles)

γ -ray radiogalaxies Cen
A
 HESS Fermi radio search
for
 SwiY‐Fermi
 HESS variabiliDes M87
variable
with
HESS

blazar evolution brightest
blazar
sample
(>
10
σ) L -1.5 FSRQ:
strong
evoluDon L -0.5 <V/V max >
=
 0.645
±
0.043 Bl
Lac:
no
evoluDon? <V/V max >
=
 0.430
±
0.055 but
few
objects L -1.1 disentangle
BH
evoluDon from
accreDon
state
 (collision
induced?
envt?)

accretion states AGN: broad-line SDSS quasars & LLAGN Körding et al. ’08

GeV μ QSO candidate μQSO
accreDng
from
massive
star? HESS 3.9
days no
complete
γγ
absorpDon
at
TeV
energies... Fermi

GeV μ QSO candidate μQSO
accreDng
from
massive
star? HESS 3.9
days no
complete
γγ
absorpDon
at
TeV
energies... Fermi

identity crisis same
radiaDon
processes:





e
+
UV*
→
γ






and








p
+
p vent
* 
→
π 0 
→
2γ same
variability:

 
 
 

dM acc /dt
versus
PWN
compression 
 
 
 
 
 
 
 

stellar
flux
variaDon
(IC
emission
and
γ+γ
→
e ± 
) same
apparent
morphology:
jet
vs.
comet
tail Mirabel ’08

γ -ray binaries LSI
+61°303 26.5
day
modulaDon VERITAS MAGIC D h a w a n ’ 0 6 Fermi Fermi Magic Veritas complex
spectrum 6.3
±
1.1
±
0.5
GeV
cut‐off searches
for
many
binaries

pulsar wind nebulae Crab
wind:
Γ
 ～ 
10 6‐7 








10 38‐41 
e ± 
s ‐1 IC
443 e ± + B → radio − X � � � � CMB TeV � � � � e ± + h ν � � � � IR → ≪ � � � � � � � � X γ � � � � e ± + h ν syn → γ + TeV CXO shocked
wind
evoluDon? wind
acceleraDon
(PoynDng
to
e ± )? (expansion,
confinement,
bow
shock) relaDvisDc
shock
acceleraDon?

PWN ageing synchrotron
losses
dominate IC
TeV
emission
to
trace
the
wind
to
long
distances PSR B1823-13 5 pc E -2 to E -2.4 50 pc HESS

pulsar jets synchrotron
aging
 ⇒ 
“injecDon”
parameters MSH
15‐52:
 
 400
<
Eemax
<
730
TeV IC
cooling
to
follow
e±
further
out need
MHD
models
for
B(r,
t) ROSAT Forot et al. ’06 ROSAT CXO

identification crisis SNR+PWN
or
mulD‐PSR/PWNe ex:
 HESS J1813-178, G12.82-0.02 HESS J1809-193