Latest results on SNRs and PWNe in the Milky Way …moriond.in2p3.fr/J09/transparents/renaud.pdfM....

M. Renaud « SNRs & PWNe in the VHE domain » 44th Rencontres de Moriond, feb 2009

Latest results on SNRs and PWNe in the Milky Way as seen in VHE gamma-rays

Matthieu Renaud

AstroParticule et CosmologieUMR 7164, Université Paris 7

Chaves et al. HESS (2008)


Outline: TeV astronomy

Individual sources & multi-wavelength observations

● Shell-type SNRs

● Plerionic SNRs (« PWNe »)– Known PWNe

– PWN candidates

Other sources & surveys

● Some cases in between...

● …diffuse VHE emission?

Concluding remarks and perspectives


Shell-type SNRs: RX J1713.7-3946

Aharonian et al. (2007a)

H.E.S.S. image1-3 keV ASCA contours

Γ = 2.04 ± 0.04E

c = 17.9 ± 3.3 TeV

Index constant across SNR

~1°

Nature of the TeV emission:Inverse-Compton or π0 decay?

Particles of >100 TeV inside the SNR...

d = 1.3 ± 0.4 kpc... AD 393 ? No thermal X-ray emission: n < 0.02 cm-3

(Cassam-Chenaï et al. 2004)


Shell-type SNRs: RX J0852-4622 (aka Vela Jr)

Aharonian et al. (2007b)

H.E.S.S. image

Power-law Γ = 2.24 ± 0.04with indication of a cutoff?


Particles of ~100 TeV inside the SNR...

~2°

d = 0.25 -1 kpc... age ? No thermal X-ray emission: n < 0.03 cm-3

(Slane et al. 2001)


Shell-type SNRs: RCW 86

Aharonian et al. (2009)

H.E.S.S. Image & 4,5,6 σ contours

Γ = 2.54 ± 0.12 (no cutoff)

Both shell and uniform sphere fit the data...

~0.6°



vs ~ 2700 km/s... SN 185? d = 1 kpc?

Faint thermal X-ray emission (Vink et al. 2006)


Shell-type SNRs: SN 1006

Naumann-Godo et al. (HESS Collaboration, 2008)

H.E.S.S. Image & Chandra (smoothed) contours

~0.5°

See the talk by M. Naumann-Godoon thursday for more details...




Shell-type SNRs

RX J1713.7-3946 (Berezhko & Völk 2008)

Pro-hadrons:Amplified B-field from the thinness of X-ray filaments (& variability) Pro-leptons:Lack of thermal X-ray emissionNature of X-ray filamentsLimitations:Size of filaments << VHE PSFsNon-imaging instruments > 10 keV


VHE Pulsar Wind Nebulae & candidates

Half of the H.E.S.S. sources is likely associated with a PSR

Young PWNe: Crab nebula, MSH 15-52... and G21.5-0.9, Kes 75

Djannati-Ataï et al. HESS (2008)Terrier et al. HESS (2008)

PSR J1848-0258 (Gotthelf 2000) τ

c = 723 yr, Ė

36 = 8.3

d ~ 6 kpc (Leahy & Tian 2008)

PSR J1833-1034 τ

c = 4.7 kyr, Ė

36 = 33, d ~ 5 kpc

age < 1kyr (Biethenholtz et al. 2008)

Particle-dominated PWNe (B < B

eq)




PSR B0833-45


HESS J1825-137 / PSR J1826-1334 HESS J0835-455 / PSR B0833-45τ

c = 21.4 kyr, Ė

36 = 2.8, O~13 d

4kpc pc τ

c = 11.3 kyr, Ė

36 = 6.9, O~1.5 d

300pc pc

Half of the H.E.S.S. sources is likely associated with a PSR

Evolved (offset) PWNe: J1825 and Vela X (De Jager & Djannati-Ataï 2008)



Association based on:

Presence of a nearby (and energetic) PSR

Theoretical background– Particle acceleration in PSR/PWN (Arons 2007, Bucciantini 2008)

– Evolution of a PWN in the ISM (Blondin et al. 2001, van der Swaluw et al. 2004)

Characteristics:

Inhomogeneous ISM and/or high vPSR

Evolved systems (τc ≥ several kyrs)

Low B (a few μG) in the VHE emissive region (de Jager & Djannati-Ataï 2008)



HESS J1809-193 / PSR J1809-1917 (Aharonian et al. 2007, Renaud et al. HESS 2008)

PSR J1809-1917: τc = 51 kyr, Ė

36 = 1.8,

O~7 d3.5kpc

pc, L1-10TeV

/Ė ~ 0.015 d23.5kpc VLA 1.4 GHz (Brogan et al., Helfand et al. 2006)

PSR J1809

Kargaltsev & Pavlov (2007)



HESS J1356-645 / PSR J1357-6429 ( Renaud et al. HESS 2008, Aharonian et al. in prep)

PSR J1357-6429: τc = 7.3 kyr, Ė

36 = 3.1,

O~5 d2.5kpc

pc, L1-10TeV

/Ė ~ 0.002 d22.5kpc

Zavlin (2007)

3 SNR candidates (Duncan et al. 1997) …But extended radio emission seenat 0.84, 2.4, 4.85 GHz... «relic» PWN?

Parkes 2.4 GHz image& H.E.S.S. contours


Some cases in between: HESS J1731-347

HESS image & 4-7σ contours

MGPS 843 MHz image ROSAT (green) contours


1.4 GHz SGPS image(Tian et al. 2008)

A new shell-type SNR G353.6-0.7 (Tian et al. 2008)

Non-thermal shell-type radio emission with R ~ 0.25°HI absorption towards adjacent HII region : d = 3.2 ± 0.8 kpc → R ~ 14 d

3.2kpc pc

ROSAT emission coincident with lower half of the SNR... thermal emission? age?


Some cases in between: CTB complex

Updated VHE resuts on CTB 37B & Chandra (Aharonian et al. A&A, 2008b, 486, 829)Discovery of CTB 37A & XMM / Chandra (Aharonian et al. A&A, 2008a, 490, 685)

MGPS 843 MHz contours

d = 5-9 kpc (Brand & Blitz 1993)age > 1500 yrs... AD 393? (Clark et al. 1975) No maser emission

rms = 2.6' ± 0.6' compatible with Rshell

~ 5'Γ = 2.65 ± 0.19F

= 1.8 [1.3-2.4] % Crab (0.5 -10 TeV)

Two SNRs, d ~ 11 kpc (Caswell et al. 1975)age > 1500 yrs... AD 393? (Clark et al. 1975)Masers & CO clouds (Reynoso et al. 2000)

rms = 4' ± 1' compatible with Rshell

~ 5'Γ = 2.30 ± 0.13F

= 2.8 [2.2-3.6] % Crab (0.5 -10 TeV)


Lots of « sources » in between...!


Aharonian et al. (2006)

Aharonian et al. (2008c)

Accelerator (i.e. SNR) – target (i.e. MC)

Delayed VHE γs from MC as a probe of Galactic PeVatrons (Gabici et al. 2007a,b)


Galactic diffuse VHE emission

Milagro survey of the Northern sky (Abdo et al. 2007a,b & 2008)

π0

ICtotal


H.E.S.S. versus Milagro: sources or diffuse emission?

5 HESS sources30° < l < 65°-2° < b < 2°

HESS J1848-010HESS J1912+101HESS J1857+026HESS J1858+020IGR J18490-0000


Chaves et al. HESS (2008)

H.E.S.S. versus Milagro: sources or diffuse emission?

> 20% of the Milagro diffuse emission is due to unresolvedsources... detected by HESS

Compatible with the expectationsof Casanova & Dingus (2008)

But need of uniform survey...


Concluding remarks

More than 60 VHE Galactic sources

● 5-9 shell-type SNRs

● 22-26 PWNe (& candidates)

● 20-30 unidentified

● VHE-ISM associations

● Diffuse emission (GC, Cygnus)

● 1-2 WR and 4-6 binaries

Madrid & Macchetto (2009)(2006)

Uniform disk(α = -1)

Spiral arms(α = -0.6)

?

Let's keep on doing (HE-)VHE astronomy with Fermi, H.E.S.S.-II, Magic-II, VERITAS...


Shell-type SNRs

Loss-limited filaments?(Vink & Laming 2003, Berezhko & Völk 2004,

Völk et al. 2005, Parizot et al. 2006)

B

Ne(E)

rs

Magnetically-limited filaments?(Pohl, Yan & Lazarian 2005)

B

Ne(E)

rs


Some cases in between: CTB complex

1-5 keV Chandra (σ=50'') image

Point-like source

HESS J1713-381

Diffuse thermal (~0.7 keV) X-ray emission{v

s > 800 km/s ; age < 5 kyr} & n ~ 0.5 cm-3

No X-ray PWN nor NT X-rays from the shellHadronic scenario → η ~ 0.4 E-1

51 d2

7kpc n-1

0.5

1.2-2.5 keV Chandra image843 MHz & COcontours

3-7 keV

Diffuse thermal (~0.8 keV) X-ray emissionExtended NT X-ray emission but no PSR

No NT X-rays from the shell« Relic » VHE PWN?

HESS J1714-385

Latest results on SNRs and PWNe in the Milky Way …moriond.in2p3.fr/J09/transparents/renaud.pdfM....

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