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
SNR shell particle acceleration
Resolved shell in VHE-g-rays
g-rays from leptonic or hadronic channels?
leptonic channel fav’d
Berezhko & Völk 2006
Ee ~ 20 (Eg )1/2 TeV
~ 110 TeV … but KN sets on .. ~100 TeV
Ep ~ Eg / 0.15 ~ 30 / 0.15 TeV ~
~ 200 TeV
... but: is SN statistics enough to fit CR energy density?
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
hadronic or leptonic ?
D = 4 kpc
GeV data solve TeV spectral degeneracy CRp normalization
·index G~2-2.2 (strong shock)
· little variation across SNR
CRp spectrumg = 1+2a+ b
measure k(p) as a function of p
from B/CNO ratio
Integrated view of VHE em. from massive SF: acceleration, diffusion, energy loss
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
Searches going on for ~35 years!!Crab pulsar: detection
EGRET + MAGIC: pl * exp [–E/16.3 GeV)]
pl *exp [–(E/20.7 GeV)2]
More psr obs’s:
First ever simultaneous
HE+VHE g-ray obs of a
p r e l i m i n a r y
Hauser & Dwek 2001Cross section (differ.):
TeV g: E
soft g: e
E ~ 1TeV
for e~0.5 eV
et al. 2008
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.
but ... missed naked-eye GRB 080319B (z=0.937)
HE+VHE data crucial to
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.
d~80 kpc2. DRACO dSph
Milky Way surrounded by small, faint companion galaxies
MAGIC ok !!
Hooper 2006Draco dSph: modeling
<sAv>, mc: WIMP annihil. cross section, mass
Ng: g-rays / annihil.
rs = 7 – 0.2 kpc
r0 = 107 – 109 Mž kpc-3
r02 rs3 = 0.03 – 6 Mž2 kpc-3
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
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
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,
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
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