summary talk: agn and gamma rays martin pohl iowa state university
DESCRIPTION
Summary Talk: AGN and Gamma Rays Martin Pohl Iowa State University. The Main Questions. How are particles accelerated? What particles are accelerated, e - or p + ? How are jets produced? Are jets. matter-dominated outflows? Poynting-dominated beams - PowerPoint PPT PresentationTRANSCRIPT
March 19, 2005XXXXth Rencontres de Moriond
Summary Talk:
AGN and Gamma Rays
Martin Pohl Iowa State University
D e c e m b e r 1 6 - 1 7 , 2 0 0 2V E R I T A S R e v i e w , W a s h i n g t o n D . C .
O v e r v i e w o f V E R I T A S S c i e n c e
A c t i v e G a l a c t i c N u c l e i *E x t r a g a l a c t i c B a c k g r o u n d L i g h t *
S h e l l - t y p e S u p e r n o v a R e m n a n t s
G a m m a - r a y P u l s a r s
P l e r i o n s
G a m m a R a y B u r s t s *
D a r k M a t t e r ( N e u t r a l i n o A n n i h i l a t i o n ) *
G a l a c t i c D i f f u s e E m i s s i o n
U n i d e n t i f i e d G a l a c t i c E G R E T S o u r c e s
L o r e n t z s y m m e t r y v i o l a t i o n
C o s m i c R a y O r i g i n
The Main Questions
• How are particles accelerated?
• What particles are accelerated, e- or p+ ?
• How are jets produced?
• Are jets
matter-dominated outflows?
Poynting-dominated beams
transitioning between the two?
D e c e m b e r 1 6 - 1 7 , 2 0 0 2V E R I T A S R e v i e w , W a s h i n g t o n D . C .
O v e r v i e w o f V E R I T A S S c i e n c e
A c t i v e G a l a c t i c N u c l e i *E x t r a g a l a c t i c B a c k g r o u n d L i g h t *
S h e l l - t y p e S u p e r n o v a R e m n a n t s
G a m m a - r a y P u l s a r s
P l e r i o n s
G a m m a R a y B u r s t s *
D a r k M a t t e r ( N e u t r a l i n o A n n i h i l a t i o n ) *
G a l a c t i c D i f f u s e E m i s s i o n
U n i d e n t i f i e d G a l a c t i c E G R E T S o u r c e s
L o r e n t z s y m m e t r y v i o l a t i o n
C o s m i c R a y O r i g i n
A Wealth Of Data
A number of excellent observatories is available or forthcoming!
• HST
• Newton, Chandra, INTEGRAL
• GLAST, AGILE?
• HESS, MAGIC, CANGAROO, VERITAS
• Milagro
• AMANDA, ICECUBE
D e c e m b e r 1 6 - 1 7 , 2 0 0 2V E R I T A S R e v i e w , W a s h i n g t o n D . C .
O v e r v i e w o f V E R I T A S S c i e n c e
A c t i v e G a l a c t i c N u c l e i *E x t r a g a l a c t i c B a c k g r o u n d L i g h t *
S h e l l - t y p e S u p e r n o v a R e m n a n t s
G a m m a - r a y P u l s a r s
P l e r i o n s
G a m m a R a y B u r s t s *
D a r k M a t t e r ( N e u t r a l i n o A n n i h i l a t i o n ) *
G a l a c t i c D i f f u s e E m i s s i o n
U n i d e n t i f i e d G a l a c t i c E G R E T S o u r c e s
L o r e n t z s y m m e t r y v i o l a t i o n
C o s m i c R a y O r i g i n
True TeV Astronomy
D e c e m b e r 1 6 - 1 7 , 2 0 0 2V E R I T A S R e v i e w , W a s h i n g t o n D . C .
O v e r v i e w o f V E R I T A S S c i e n c e
A c t i v e G a l a c t i c N u c l e i *E x t r a g a l a c t i c B a c k g r o u n d L i g h t *
S h e l l - t y p e S u p e r n o v a R e m n a n t s
G a m m a - r a y P u l s a r s
P l e r i o n s
G a m m a R a y B u r s t s *
D a r k M a t t e r ( N e u t r a l i n o A n n i h i l a t i o n ) *
G a l a c t i c D i f f u s e E m i s s i o n
U n i d e n t i f i e d G a l a c t i c E G R E T S o u r c e s
L o r e n t z s y m m e t r y v i o l a t i o n
C o s m i c R a y O r i g i n
Jets Everywhere?
SNR have smallanisotropy!
Cas A (Hwang et al. 2004)
Red, blue: ejecta
Green: non-thermal
D e c e m b e r 1 6 - 1 7 , 2 0 0 2V E R I T A S R e v i e w , W a s h i n g t o n D . C .
O v e r v i e w o f V E R I T A S S c i e n c e
A c t i v e G a l a c t i c N u c l e i *E x t r a g a l a c t i c B a c k g r o u n d L i g h t *
S h e l l - t y p e S u p e r n o v a R e m n a n t s
G a m m a - r a y P u l s a r s
P l e r i o n s
G a m m a R a y B u r s t s *
D a r k M a t t e r ( N e u t r a l i n o A n n i h i l a t i o n ) *
G a l a c t i c D i f f u s e E m i s s i o n
U n i d e n t i f i e d G a l a c t i c E G R E T S o u r c e s
L o r e n t z s y m m e t r y v i o l a t i o n
C o s m i c R a y O r i g i n
RX J1713-3946
HESS spectrum
D e c e m b e r 1 6 - 1 7 , 2 0 0 2V E R I T A S R e v i e w , W a s h i n g t o n D . C .
O v e r v i e w o f V E R I T A S S c i e n c e
A c t i v e G a l a c t i c N u c l e i *E x t r a g a l a c t i c B a c k g r o u n d L i g h t *
S h e l l - t y p e S u p e r n o v a R e m n a n t s
G a m m a - r a y P u l s a r s
P l e r i o n s
G a m m a R a y B u r s t s *
D a r k M a t t e r ( N e u t r a l i n o A n n i h i l a t i o n ) *
G a l a c t i c D i f f u s e E m i s s i o n
U n i d e n t i f i e d G a l a c t i c E G R E T S o u r c e s
L o r e n t z s y m m e t r y v i o l a t i o n
C o s m i c R a y O r i g i n
TeV / keV relation => Emission inside of the forward shock!
Little thermal X-ray emission => nH ~ ne < 0.1 /cc
=> Ecr > (1050 erg) Dkpc2
TeV electrons are not loss-limited!
=> power-law spectrum N(E) ~ E-3 unlikely
D e c e m b e r 1 6 - 1 7 , 2 0 0 2V E R I T A S R e v i e w , W a s h i n g t o n D . C .
O v e r v i e w o f V E R I T A S S c i e n c e
A c t i v e G a l a c t i c N u c l e i *E x t r a g a l a c t i c B a c k g r o u n d L i g h t *
S h e l l - t y p e S u p e r n o v a R e m n a n t s
G a m m a - r a y P u l s a r s
P l e r i o n s
G a m m a R a y B u r s t s *
D a r k M a t t e r ( N e u t r a l i n o A n n i h i l a t i o n ) *
G a l a c t i c D i f f u s e E m i s s i o n
U n i d e n t i f i e d G a l a c t i c E G R E T S o u r c e s
L o r e n t z s y m m e t r y v i o l a t i o n
C o s m i c R a y O r i g i n
Hadronic emission?
Leptonic emission?
• Consistent with extrapolation from EGRET Any rapidly rising component to explain >1 GeV excess cannot continue to 1 TeV
Milagro detects diffuse galactic emission at ~ 1 TeV
D e c e m b e r 1 6 - 1 7 , 2 0 0 2V E R I T A S R e v i e w , W a s h i n g t o n D . C .
O v e r v i e w o f V E R I T A S S c i e n c e
A c t i v e G a l a c t i c N u c l e i *E x t r a g a l a c t i c B a c k g r o u n d L i g h t *
S h e l l - t y p e S u p e r n o v a R e m n a n t s
G a m m a - r a y P u l s a r s
P l e r i o n s
G a m m a R a y B u r s t s *
D a r k M a t t e r ( N e u t r a l i n o A n n i h i l a t i o n ) *
G a l a c t i c D i f f u s e E m i s s i o n
U n i d e n t i f i e d G a l a c t i c E G R E T S o u r c e s
L o r e n t z s y m m e t r y v i o l a t i o n
C o s m i c R a y O r i g i n
Soft Gamma-ray Repeaters
SGR 1806-20
Period: 7.56 s
Giant flare
Initial spike:
Liso ~ 1046 erg/s
D e c e m b e r 1 6 - 1 7 , 2 0 0 2V E R I T A S R e v i e w , W a s h i n g t o n D . C .
O v e r v i e w o f V E R I T A S S c i e n c e
A c t i v e G a l a c t i c N u c l e i *E x t r a g a l a c t i c B a c k g r o u n d L i g h t *
S h e l l - t y p e S u p e r n o v a R e m n a n t s
G a m m a - r a y P u l s a r s
P l e r i o n s
G a m m a R a y B u r s t s *
D a r k M a t t e r ( N e u t r a l i n o A n n i h i l a t i o n ) *
G a l a c t i c D i f f u s e E m i s s i o n
U n i d e n t i f i e d G a l a c t i c E G R E T S o u r c e s
L o r e n t z s y m m e t r y v i o l a t i o n
C o s m i c R a y O r i g i n
Magnetar
Isolated neutron star B ~ (1014 – 1015) G
D e c e m b e r 1 6 - 1 7 , 2 0 0 2V E R I T A S R e v i e w , W a s h i n g t o n D . C .
O v e r v i e w o f V E R I T A S S c i e n c e
A c t i v e G a l a c t i c N u c l e i *E x t r a g a l a c t i c B a c k g r o u n d L i g h t *
S h e l l - t y p e S u p e r n o v a R e m n a n t s
G a m m a - r a y P u l s a r s
P l e r i o n s
G a m m a R a y B u r s t s *
D a r k M a t t e r ( N e u t r a l i n o A n n i h i l a t i o n ) *
G a l a c t i c D i f f u s e E m i s s i o n
U n i d e n t i f i e d G a l a c t i c E G R E T S o u r c e s
L o r e n t z s y m m e t r y v i o l a t i o n
C o s m i c R a y O r i g i n
BUT
Rotational energy ~ 10 M R2 / P2 ~ 1045 erg
Magnetic energy ~ B2 R3 / 6 ~ B152 1047 erg
Observed: L ~ 1046 erg, no period change observed (yet)
Probably a jet, not an isotropic fireball!
D e c e m b e r 1 6 - 1 7 , 2 0 0 2V E R I T A S R e v i e w , W a s h i n g t o n D . C .
O v e r v i e w o f V E R I T A S S c i e n c e
A c t i v e G a l a c t i c N u c l e i *E x t r a g a l a c t i c B a c k g r o u n d L i g h t *
S h e l l - t y p e S u p e r n o v a R e m n a n t s
G a m m a - r a y P u l s a r s
P l e r i o n s
G a m m a R a y B u r s t s *
D a r k M a t t e r ( N e u t r a l i n o A n n i h i l a t i o n ) *
G a l a c t i c D i f f u s e E m i s s i o n
U n i d e n t i f i e d G a l a c t i c E G R E T S o u r c e s
L o r e n t z s y m m e t r y v i o l a t i o n
C o s m i c R a y O r i g i n
The Galactic Center
A supermassive black hole M ~ 3 106 Msolar
Confirmed by stellar orbits
Inefficient accretion low luminosity
Quasi-thermal relativistic plasma
Nonthermal power-law tail during flares
D e c e m b e r 1 6 - 1 7 , 2 0 0 2V E R I T A S R e v i e w , W a s h i n g t o n D . C .
O v e r v i e w o f V E R I T A S S c i e n c e
A c t i v e G a l a c t i c N u c l e i *E x t r a g a l a c t i c B a c k g r o u n d L i g h t *
S h e l l - t y p e S u p e r n o v a R e m n a n t s
G a m m a - r a y P u l s a r s
P l e r i o n s
G a m m a R a y B u r s t s *
D a r k M a t t e r ( N e u t r a l i n o A n n i h i l a t i o n ) *
G a l a c t i c D i f f u s e E m i s s i o n
U n i d e n t i f i e d G a l a c t i c E G R E T S o u r c e s
L o r e n t z s y m m e t r y v i o l a t i o n
C o s m i c R a y O r i g i n
D e c e m b e r 1 6 - 1 7 , 2 0 0 2V E R I T A S R e v i e w , W a s h i n g t o n D . C .
O v e r v i e w o f V E R I T A S S c i e n c e
A c t i v e G a l a c t i c N u c l e i *E x t r a g a l a c t i c B a c k g r o u n d L i g h t *
S h e l l - t y p e S u p e r n o v a R e m n a n t s
G a m m a - r a y P u l s a r s
P l e r i o n s
G a m m a R a y B u r s t s *
D a r k M a t t e r ( N e u t r a l i n o A n n i h i l a t i o n ) *
G a l a c t i c D i f f u s e E m i s s i o n
U n i d e n t i f i e d G a l a c t i c E G R E T S o u r c e s
L o r e n t z s y m m e t r y v i o l a t i o n
C o s m i c R a y O r i g i n
D e c e m b e r 1 6 - 1 7 , 2 0 0 2V E R I T A S R e v i e w , W a s h i n g t o n D . C .
O v e r v i e w o f V E R I T A S S c i e n c e
A c t i v e G a l a c t i c N u c l e i *E x t r a g a l a c t i c B a c k g r o u n d L i g h t *
S h e l l - t y p e S u p e r n o v a R e m n a n t s
G a m m a - r a y P u l s a r s
P l e r i o n s
G a m m a R a y B u r s t s *
D a r k M a t t e r ( N e u t r a l i n o A n n i h i l a t i o n ) *
G a l a c t i c D i f f u s e E m i s s i o n
U n i d e n t i f i e d G a l a c t i c E G R E T S o u r c e s
L o r e n t z s y m m e t r y v i o l a t i o n
C o s m i c R a y O r i g i nDDo we understand AGN?
Radio loud vs. Radio quiet
Does not depend on type of host galaxy!
Core dominance vs Lobe dominance
Appears to depend on accretion rate
Marchesini, C
elotti & F
errarese 04
FRII/HEG absorbed
= 1
m
2 - MBH and Accretion rate
MBH
FRI
•
10-3
Indication for bimodal
accretion rate distribution
m
QSO
FRII/LEG FRII/BLRG
- PKS 1127-145 at z=1.187
- offsets as possible indicators of acceleration in the wake of the shock (Hardcastle et al. 2003)
Siemiginowska et al. 2002
Poynting vs. matter
• Blob deceleration observed in microquasars
• Circular polarization => strong, ordered magnetic field
• no observational evidence for thermal matter in AGN jets
• low RM in large-scale structures => low ne
• in situ acceleration required in jets
Plasma clouds in large-scale guiding magnetic field?
D e c e m b e r 1 6 - 1 7 , 2 0 0 2V E R I T A S R e v i e w , W a s h i n g t o n D . C .
O v e r v i e w o f V E R I T A S S c i e n c e
A c t i v e G a l a c t i c N u c l e i *E x t r a g a l a c t i c B a c k g r o u n d L i g h t *
S h e l l - t y p e S u p e r n o v a R e m n a n t s
G a m m a - r a y P u l s a r s
P l e r i o n s
G a m m a R a y B u r s t s *
D a r k M a t t e r ( N e u t r a l i n o A n n i h i l a t i o n ) *
G a l a c t i c D i f f u s e E m i s s i o n
U n i d e n t i f i e d G a l a c t i c E G R E T S o u r c e s
L o r e n t z s y m m e t r y v i o l a t i o n
C o s m i c R a y O r i g i n
D e c e m b e r 1 6 - 1 7 , 2 0 0 2V E R I T A S R e v i e w , W a s h i n g t o n D . C .
O v e r v i e w o f V E R I T A S S c i e n c e
A c t i v e G a l a c t i c N u c l e i *E x t r a g a l a c t i c B a c k g r o u n d L i g h t *
S h e l l - t y p e S u p e r n o v a R e m n a n t s
G a m m a - r a y P u l s a r s
P l e r i o n s
G a m m a R a y B u r s t s *
D a r k M a t t e r ( N e u t r a l i n o A n n i h i l a t i o n ) *
G a l a c t i c D i f f u s e E m i s s i o n
U n i d e n t i f i e d G a l a c t i c E G R E T S o u r c e s
L o r e n t z s y m m e t r y v i o l a t i o n
C o s m i c R a y O r i g i n
=> EBL studies possible Quiet state detectable
D e c e m b e r 1 6 - 1 7 , 2 0 0 2V E R I T A S R e v i e w , W a s h i n g t o n D . C .
O v e r v i e w o f V E R I T A S S c i e n c e
A c t i v e G a l a c t i c N u c l e i *E x t r a g a l a c t i c B a c k g r o u n d L i g h t *
S h e l l - t y p e S u p e r n o v a R e m n a n t s
G a m m a - r a y P u l s a r s
P l e r i o n s
G a m m a R a y B u r s t s *
D a r k M a t t e r ( N e u t r a l i n o A n n i h i l a t i o n ) *
G a l a c t i c D i f f u s e E m i s s i o n
U n i d e n t i f i e d G a l a c t i c E G R E T S o u r c e s
L o r e n t z s y m m e t r y v i o l a t i o n
C o s m i c R a y O r i g i n
1. Counterparts and redshifts have been found for many
long bursts
2. No counterpart or redshift has been found for any short burst
3. There are two morphological classes of GRBs, long bursts (~20 s duration) and short bursts (~0.2 s duration)
4. Most of the long bursts display long-wavelength (radio and optical) “afterglows”; but some of them have no detectable optical or radio counterparts (“dark” bursts)
5. There is good evidence which links some long bursts to the deaths of massive stars
6. The energy spectra of the long bursts form a continuum, from X-ray flashes (with few or no γ-rays), X-ray rich bursts, and GRBs
7. There is no experimental evidence to suggest that any class of burst (long/short, X-ray rich, dark) has a different origin, or a different spatial distribution, from any other class – but there are many theories which do suggest different origins
Attempts to unify GRB with SGR/XRF need more evidence!
Association of GRB with star-forming regions: X-ray lines Distribution of OT location in their host galaxies
(Bloom et al) SN-GRB connection X-ray absorption column densities consistent with
NH=1021-22 cm-2 in GMC
Since the typical density in a GMC is n=102-104 cm-3 why the density derived from the standard fireball (e.g. Panaitescu, Kumar et al..) model is 3-4 orders of magnitude lower ? Wind ejection by progenitor.
Wind environment is expected from progenitor (collapsar, in particular) but most afterglows are consistent with constant density profile ..
December 16-17, 2002 VERITAS Review, Washington D.C.
Overview of VERITAS Science
Active Galactic Nuclei *Extragalactic Background Light *
Shell-type Supernova Remnants
Gamma-ray PulsarsPlerions
Gamma Ray Bursts *
Dark Matter (NeutralinoAnnihilation) *
Galactic Diffuse Emission
Unidentified Galactic EGRET Sources
Lorentzsymmetry violationCosmic Ray Origin
35% of the GRBs detected by BeppoSAX and the IPN had no detectable optical counterparts – why?
1. Absorbed by dust within the host galaxy? 2. Intrinsically faint and/or rapidly fading?3. High redshift?
Only ~10% of the bursts detected by HETE are optically dark HETE gets positions out to the astronomers faster
than BeppoSAX and the IPN did Swift is now doing the same, and carrying out optical
observations within minutes Some Swift bursts do appear to be optically dark
Confirmed byobservation? Not so far
D e c e m b e r 1 6 - 1 7 , 2 0 0 2V E R I T A S R e v i e w , W a s h i n g t o n D . C .
O v e r v i e w o f V E R I T A S S c i e n c e
A c t i v e G a l a c t i c N u c l e i *E x t r a g a l a c t i c B a c k g r o u n d L i g h t *
S h e l l - t y p e S u p e r n o v a R e m n a n t s
G a m m a - r a y P u l s a r s
P l e r i o n s
G a m m a R a y B u r s t s *
D a r k M a t t e r ( N e u t r a l i n o A n n i h i l a t i o n ) *
G a l a c t i c D i f f u s e E m i s s i o n
U n i d e n t i f i e d G a l a c t i c E G R E T S o u r c e s
L o r e n t z s y m m e t r y v i o l a t i o n
C o s m i c R a y O r i g i n
Beaming angles range from ~1º to ~25º; average ~ 4º
Distribution of energy assumed uniform within the beam
Energy ~ 1051 erg
Isotropic energies,no beaming
Correctedfor beaming
Frail et al. 2001
D e c e m b e r 1 6 - 1 7 , 2 0 0 2V E R I T A S R e v i e w , W a s h i n g t o n D . C .
O v e r v i e w o f V E R I T A S S c i e n c e
A c t i v e G a l a c t i c N u c l e i *E x t r a g a l a c t i c B a c k g r o u n d L i g h t *
S h e l l - t y p e S u p e r n o v a R e m n a n t s
G a m m a - r a y P u l s a r s
P l e r i o n s
G a m m a R a y B u r s t s *
D a r k M a t t e r ( N e u t r a l i n o A n n i h i l a t i o n ) *
G a l a c t i c D i f f u s e E m i s s i o n
U n i d e n t i f i e d G a l a c t i c E G R E T S o u r c e s
L o r e n t z s y m m e t r y v i o l a t i o n
C o s m i c R a y O r i g i n
Theory of GRBs
Old competitors:
Semi-collimated fireballs confined plasma balls
How to explain the scalings and spectra?
• Photopair production on reflected emission of pairs
• Neutron decay in the upstream region
• Pair production in the upstream or shear region
• High compactness in the dense downstream plasma