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GeV-TeV prospects & results. Issues : Origin & diffusion properties of Galactic CRs: Main accelerators: SNRs? Diffusion: measure it? Galaxies : massive SFR AGNs : variability, SED, EBL GRBs : SED, emission pulsars : emission region Clusters of galaxies : NT

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Massimo persic inaf infn trieste magic collaboration

GeV-TeV prospects & results

  • Issues:

  • Origin & diffusion properties

  • of Galactic CRs:

  • Main accelerators: SNRs?

  • Diffusion: measure it?

  • Galaxies: massive SFR

  • AGNs: variability, SED, EBL

  • GRBs: SED, emission

  • pulsars: emission region

  • Clusters of galaxies: NT

  • side of structure formation

  • Galaxy halos: DM

Massimo Persic

INAF-INFN Trieste

MAGIC Collaboration

Massimo PersicINAF/INFN-Trieste MAGIC Collaboration


SNR RX J1713.7-3946

H.E.S.S.

SNR shell  particle acceleration

Resolved shell in VHE-g-rays

g-rays from leptonic or hadronic channels?

leptonic channel fav’d

Aharonian+ 2006

3EG J1714-3857

hadronic

channel

favored

B=100mG

Berezhko & Völk 2006


Leptonic:

Ee ~ 20 (Eg )1/2 TeV

~ 110 TeV … but KN sets on ..  ~100 TeV

Hadronic:

Ep ~ Eg / 0.15 ~ 30 / 0.15 TeV ~

~ 200 TeV

... but: is SN statistics enough to fit CR energy density?


Hess j1813 178

Albert+ 2006

HESS J1813-178

???

ABBA

MAGIC

AGILE

Fermi LAT

IACT

Hadronic: 2MÄ of target gas, exp-cutoff proton distrib: a=2.1, Ec=100 TeV,

np=6cm-3, L(0.4-6 TeV)=2.5E+34erg/s

Leptonic: B=10mG, exp-cutoff electron distrib: a=2.0, Ec=20TeV

VHE g-rays:

hadronic or leptonic ?

D = 4 kpc

GeV data  solve TeV spectral degeneracy  CRp normalization


Aharonian + 2006

·index G~2-2.2 (strong shock)

· little variation across SNR

  • GeV+TeV spatially resolved spectroscopy

  • young SNRs (t<tcool (p,e)):

    CRp spectrumg = 1+2a+ b

     measure k(p) as a function of p

  • = pb…b~0.6 ?

    from B/CNO ratio

from VHE

from radio


Galaxies
Galaxies

Integrated view of VHE em. from massive SF: acceleration, diffusion, energy loss

Arp 220


M82: most promising candidate

MP, Rephaeli & Arieli 2008

diffusion-loss eq. solved

F(>0.1 TeV) ~

~ 2 x10-12 cm-2s-1

MAGIC or VERITAS:

hundreds of hours

F(>100 MeV) ~

~ 10-8 cm-2s-1

Fermi LAT:

first-year scan


Crab pulsar detection

First detection of pulsed emission at >25 GeV.

Searches going on for ~35 years!!

Crab pulsar: detection

EGRET + MAGIC: pl * exp [–E/16.3 GeV)]

pl *exp [–(E/20.7 GeV)2]

  • at least for Crab pulsar,

  • polar cap scenario challenged

More psr obs’s:

ms pulsars?


Active galactic nuclei
Active Galactic Nuclei

IACT

Fermi

AGILE



Jul/Aug & Nov/Dec 2007

(S+E)SC model

Ghisellini+ 2007

3C454.3

z=0.859

AGILE trigger

MAGIC

MAGIC


March/April 2008

AGILE

MAGIC

Fermi

First ever simultaneous

HE+VHE g-ray obs of a

blazar!

p r e l i m i n a r y

PG 1553+113

(?)


  • Target-of-Opportunity (ToO) obs’s:  high states

    • trigger in other l (g: AGILE, Fermi; x: Swift, Suzaku; optical: KVA)

    • simultaneous mwl observations:

    • evolution of emitting particle population

      • emergy-dependent evolution in time

  • Monitoring obs’s:  low states

    • in several l

    • check quiet emission of blazar

    • properties of steady-state particle spectrum

      • emergy-dependent evolution in time



Cross section differ

EBL

Hauser & Dwek 2001

Cross section (differ.):

Stecker+ 2006

Optical depth:

TeV g: E

soft g: e

E ~ 1TeV

 sggmax

for e~0.5 eV

(~2mm, K-band)

Heitler 1960

x=1+cosq

Slkkkàkàk-lkn

Stecker 1999

IBL absorption


Franceschini

et al. 2008


Measuring EBL(z).

Tools: sources with sound modeling & minimum number of parameters  BLLacs!?

(l.o.s. orientation, jet-only emission, single-zone SSC).

1) Based on GeV data, set up a list of BLLacs whose predicted VHE flux is detectable with IACTs.

Populate redshift space (out to z ~ 1) as closely as possible.

2) For each BLLac source, obtain simultaneous well-sampled mwl SEDs (at optical, X-ray, HE, and VHE frequencies) corresponding to different source states (low, high).

This amounts to having several SEDs at each given z.

Since in such SEDs the Compton peak typically occurs in the EBL-unaffected region <100GeV, using HE data the SSC model can be closed with substantially no EBL-induced bias. Hence, the SSC model in the VHE region (>100 GeV) is known and can be assumed to represent the intrinsic VHE source spectrum.

Contrasting it with data (measured between photon energies E1 and E2), we obtain nEBL(z) at redshift z and in the energy interval between, locally at redshift z, 0.5/[E2(1+z)] eV and 0.5/[E1(1+z)] eV.

3) Repeating procedure (2) with different SEDs (i.e.: different sources, or same source in different emission states) at the same z, in principle we should obtain consistent determinations of the EBL. In practice, we will reduce the statistic error affecting each determination of nEBL(z).

4) Selecting BLLac objects progressively farther away, we will measure EBL at different z. By repeating steps (2),(3) we will in principle obtain measures of nEBL(z) -- out to z ~1.


G amma r ay b ursts grb s
Gamma-Ray Bursts (GRBs)

  • · Most energetic explosions since Big Bang (1054 erg if isotropic)

  • · Astrophysical setting unknown (hypernova?)

  • · Emission mechanism unknown (hadronic vs leptonic, beaming,

  • size of emitting region, role of environment, … … )

  • Cosmological distances (z >> 1)

    but ... missed naked-eye GRB 080319B (z=0.937)

Gggg

HESS

MAGIC

----------------------------

MAGIC

ST

HE+VHE data crucial to

constrain/unveil emission

mechanism(s)


GRBs

Intrinsically:

Nearby: z=0.937

Brightest ever observed in optical

Exceedingly high isotropic-equivalent in soft g-rays

080319B  missed obs of “naked-eye” GRB

Swift/BAT could have observed it out to z=4.9

1m-class telescope could observe out to z=17

Missed by both AGILE (Earth screening) and MAGIC (almost dawn)

next BIG ONE awaited !!



Targets: Draco, Willman-I, Segue gals.


2 draco dsph

DRACO dSph

high M/L>200

d~80 kpc

2. DRACO dSph

Milky Way surrounded by small, faint companion galaxies

Northern source 

MAGIC ok !!

  • dSph’s very DM-dominated objects.

  • Distances,M/L ratios16<D/kpc<250 kpc, 30<M/L<300


Draco dsph modeling

d~80 kpc

Bergström &

Hooper 2006

Draco dSph: modeling

total DM

annihil. rate

<sAv>, mc: WIMP annihil. cross section, mass

g-ray flux

Ng: g-rays / annihil.

cusped

profile

upper limit

cored

profile

g-ray flux

rs = 7 – 0.2 kpc

r0 = 107 – 109 Mž kpc-3

r02 rs3 = 0.03 – 6 Mž2 kpc-3


_

bb

t t

t+t-

_

min. cored

W+W-

Fermi

1-yr exp.

max. cusped

MAGIC

40-h exp.

ZZ

Bergström & Hooper 2006

IACT neutralino detection:

<sAv> ³ 10-25 cm3s-1

unid’d GeV sky brightness fluct’s

to be followed up a TeV energies

Stoehr + 2003


Draco dsph obs d magic arxiv 0711 2574
Draco dSph obs’d MAGIC arXiv:0711.2574

7.8 hr

May 2007

m0 > 2 TeV … Wc < (WDM+2dWDM)WMAP=0.113

m0 > 2 TeV … Wc < (WDM-2dWDM)WMAP=0.09751

m0£ 2 TeV … Wc < (WDM+2dWDM)WMAP=0.113

m0£ 2 TeV … Wc< (WDM-2dWDM)WMAP=0.09751




Outlook

GeV+TeV: wide spectral coverage to observe Galactic-environment

phenomena useful to solve long-standing issues about CRs.

SNRs, molecular clouds  HE+VHE emission mechanism,

energy-dependent diffusion.

GRBs, star-forming galaxies  SFR(z)

Galaxy clusters  NT side of structure formation

Pulsars  measure magnetosph. emission cutoff

AGNs  solve (S+E)SC model of AGNs

measure EBL(z)

probe short-time variability as function of E

simultaneous mwl monitoring of low-state

ToO obs’s of high states

DM halos  depending on mc, decay channels, central density, distance



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