The Interactions between the SNRs and Their Environments

The Interactions between the SNRs
and Their Environments
Dissertation committee:
Zigao Dai (NJU)
Yongfeng Huang (NJU)
WenwuTian(CAS-NAO)
Fangjun Lu (CAS-IHEP)
Li Ji (CAS-PMO)
Xin
Zhou
2011 May 18
Supervisors:
Yang Chen (NJU) &
Fabrizio Bocchino (INAF-OAPa)

Forward Shock (FS)
Contact Discontinuity (CD)
Reverse Shock (RS)
SNR Basics
Shocked CSM/ISM
Shocked ejecta
Unshocked ejecta
Pulsar
/PWN
Mixed-Morphology/
Thermal Composite

Inhomogeneities
ISM
Asymmetric stellar-wind
(g cm -
ρ
CSM
3 )ρ
of CSM/ISM
Kwok (2007)
Dwarkadas (2007)
p (dyn cm- 2 )ρ

SNR-cloud Interaction
γ-ray source
Wardle & Yusef-Zadeh (2002)
Hydrodynamic evolution
(Thermal Conduction)
--the Cygnus Loop;
Ionization history
(Over-Ionization)
--W49B;
Molecular chemistry
--Kes 69&W49B;
Hadronic CRs.

Thermal Conduction (TC)
Without TC With TC
Orlando et al. (2005)
Stronger transmitted shock;
Weaker reflected shock;
Depress the HY instabilities;
Reducing the mixing of the
cloud;
Evaporating the cloud
material.
Efficiency of TC in
real case?

Ionization Temp.
Over-Ionization (OI)
Kawasaki et al. (2005)
Ionization Equilibrium
Ozawa et al. (2009)
Origin of OI?
W49B by Suzaku

My Works
• MCs distribution around Kes 69
• SNR-cloudlet interaction in the Cygnus Loop
• MCs distribution around W49B; Origin of OI
in W49B
• Conclusions and Prospects

Kes
69
4.5 μm & 24 μm
Red:Radio 1.4 GHz
Green:12CO (1-0) 79-82 km/s
White contour:X-ray
•Fast shock ~10 3 km/s, slow shock ~10 km/s;
•Swept up by the progenitor’s stellar wind;
•Association with 85 km/s MC
5.2 & 9.6 kpc.

Kes
Galactic latitude
-0:30:00
69 --
HI 21 cm
6.78 km/s
22:00.00 21:40.00
Galactic longitude
•Absorption feature:4, 6, 15, 40, 48, 67, 70, 82, and 88 km/s
•No absorption found around tangent point(7.4 kpc and 113.7 km/s)
D < 7.4 kpc
T B (K)
D ~ 5.2 kpc, then R ~ 13 pc age ~ 4.4 kyr
e -τ
Velocity (km/s)

The Cygnus Loop
XA
region,
observed
by XMM
ROSAT HRI
•Curved shock
front;
•“Dense finger”;
•Clumpy
features with
hot corona;
•Long strip;
•Distribution of
ejecta.

The Cygnus Loop --
•Abundance of shocked
ISM is low;
•Hot component in
regions 4 and 9 mainly
originate from ejecta;
•T ejecta >T ISM .
Spectral Analysis:
Region 1
Region 9

The Cygnus Loop --
•Flatter slopes (> -0.45);
•Region 7&8: Less efficient TC;
•Region 3&4: ejecta
ascending trend
Role of TC
TC is predominant in
all of the shock-cloud
interaction regions.

W49B --
Multiband
X-ray jet-like feature + sharp shell
Near-IR + Mid-IR + Radio loops
Molecular shell
Observations
Credit: X-ray: NASA/CXC/SSC/J. Keohane et al.;
Infrared: Caltech/SSC/J.Rho and T. Jarrett
Red: 2.12 micron molecular hydrogen
Green: 1.64 micron [FeII]
Blue: Chandra X-ray
Radio continuum
Lacey et al. (2001)
by Zhou
mid-IR

W49B --
CO (1-0)
CO (2-1)
CO Observations
v LSR (km/s)
SMT SRAO
Point L2
Point R1
Probably associated with 40 km/s MC
D ~ 2.3 & 9.3 kpc
CO (1-0)
CO (2-1)

T B (K)
W49B --
e -τ
HI 21 cm
Velocity (km/s)
•Absorption feature:7,16, 20, 35, 40, 52, 60, and 70 km/s
•There is absorption feature around tangent point(at ~71.7 km/s)
D > 5.8 kpc
•No absorption feature at 12 km/s
D < 11.1 kpc
D ~ 9.3kpc

W49B --
Model
Red: 2.12 micron molecular hydrogen
Green: 1.64 micron [FeII]
Blue: Chandra X-ray
east
west
Credit: X-ray: NASA/CXC/SSC/J. Keohane et al.;
Infrared: Caltech/SSC/J.Rho and T. Jarrett

W49B --
Model
Fluid equations of mass, momentum,
and energy conservation:
Thermal conduction (both classical
and saturated considered):
Continuity equations for each ion
species:
represents the collisional and dielectronic
recombination coeffecients, and represents
the collisional ionization coefficients.

W49B --
Simulation Results
Density Temperature
Ionization
equilibrium
underionization overionization near
ionization
equilibrium

W49B --
Simulation Results
Miceli et al. (2010)
Zhou et al. (2010)

Conclusions:
Thermal conduction is important to understand the hydrodynamic evolution
of shock-cloud interaction;
The jet-like feature in SNR could be a hydrodynamical effect;
The overionization effect could be understood in the shock-cloud
interaction process;
The distribution of MCs around SNRs could be greatly affected by the
progenitor’s stellar-wind.

Brief Summary:
Associated 85 km/s MC shell in Kes 69 as the remnant of the progenitor's
stellar wind, two types of shock, d~5.2kpc, t age~4.4 kyr;
In the XA region of the Cygnus Loop, the shock is interacting with dense
and clumpy ISM, and there is a long bent “finger” protruding into the
remnant, TC is important in the shock-cloud interactions,the abundance of
the surrounding ISM is lower than solar value;
Probable associated semi-circular 40 km/s MC in W49B as the remnant of
the progenitor's stellar wind, d~9.3 kpc, the numerical model provides us
explanations of the origins of X-ray morphology and overionized plasma,
t age~2.3kyr.

Prospects:
The emissions of NEI plasma need to be examined;
To understand the SNR-MC interactions, detailed model of molecular
reactions is needed.
• The structure of the ISM
• Origin of SNRs with peculiar morphology
• CRs in SNR

Refereed papers
Publications:
1.Zhou, X., Miceli, M., Bocchino, F., Orlando, S., and Chen, Y. 2011, MNRAS, in
Press (arXiv: 1103.2290)
2.Su, Y., Chen, Y., Yang, J., Koo, B. C., Zhou, X., Lu, D. R., Jeong, I. G., and
DeLaney, T. 2010, ApJ, 727, 43
3.Zhou, X., Bocchino, F., Miceli, M., Orlando, S., and Chen, Y. 2010, MNRAS,
406, 223
4.Jiang, B., Chen, Y., Wang, J. Z., Su, Y., Zhou, X., Safi-Harb, S., and DeLaney, T.
2010, ApJ, 712, 1147
5.Orlando, S., Bocchino, F., Miceli, M., Zhou, X., Reale, F., and Peres, G. 2010,
A&A, 514,290
6.Su, Y., Chen, Y., Yang, J., Koo, B. C., Zhou, X., Jeong, I. G., and Zhang, C. G.
2009, ApJ, 694, 376
7.Zhou, X. , Chen, Y., Su, Y., and Yang, J. 2009, ApJ, 691, 516