Shock cloud interaction in the vela snr the xmm newton view
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Shock-cloud interaction in the Vela SNR: the XMM-Newton view. M. Miceli 1 , F. Bocchino 2 , A. Maggio 2 , F. Reale 1 1.Dipartimento di Scienze Fisiche ed Astronomiche, Universit à di Palermo 2. INAF-Osservatorio Astronomico G. S. Vaiana di Palermo. Low spatial resolution (> 5’).

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Shock-cloud interaction in the Vela SNR: the XMM-Newton view

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Shock cloud interaction in the vela snr the xmm newton view

Shock-cloud interaction in the Vela SNR: the XMM-Newton view

M. Miceli1, F. Bocchino2, A. Maggio2, F. Reale1

1.Dipartimento di Scienze Fisiche ed Astronomiche, Università di Palermo

2. INAF-Osservatorio Astronomico G. S. Vaiana di Palermo


Interaction between the blast wave shock of a middle aged snr and the inhomogeneities of the ism

Low spatial resolution

(> 5’).

Low Aeff.

Low spectral resolution (E/DE < 2)

Low Aeff.

Geometry of the system?

No detailed comparison between X-ray and optical emission.

Difficulty in estimating the physical parameters of the plasma.

Detecting NEI effects.

Interaction between the blast-wave shock of a middle-aged SNR and the inhomogeneities of the ISM.

The analysis of past X-ray observations left many open issues:

Impossibility of unambiguously describing the physics of the shock-cloud interaction.


The data

Thedata

  • Guaranteed Time Observation.

  • Coordinates: a (2000)=8h35m44s; d (2000) = -42º35’29’’.

  • Exposure time: 26.8 ksec (PN); 31.1 ksec (MOS).

  • Mode: Extended Full Frame (PN); Large Window (MOS).

  • Filter: Medium.


Shock cloud interaction in the vela snr the xmm newton view

  • Our aims:

  • Describing the morphology of the ISM clouds (shape, dimension, spatial distribution…).

  • Obtaining information about the physical properties and the internal structure of the clouds.

  • Studying the dynamics and the evolution of the shock-cloud interaction.

ROSAT All Sky Survey (0.2-2.4 keV)


Shock cloud interaction in the vela snr the xmm newton view

EPIC count rate images

RegNE

~ 2.4 pc

0

cnt/s

7.210-5

0

cnt/s

10-4

FilD


Shock cloud interaction in the vela snr the xmm newton view

Comparison between X-ray and optical emission in the FilD region

  • Color coding:

  • Green: Ha emission

  • Violet: OIII emission

  • Red: X-ray contour levels (0.3-0.5 keV)

Maximum X-ray contour levels are just outside the optical filament: the optical emission follows a path that grazes, without crossing, the brightest X-ray FilD regions.


Shock cloud interaction in the vela snr the xmm newton view

Regions selected for spectral analysis

0.3-2 keV

  • Color coding:

  • Black: FilD

  • Red: South-Western region

  • Blue: RegNE

In each region the mean photon energy E has low fluctuations:

DE/Eavg  0.04


Shock cloud interaction in the vela snr the xmm newton view

Spectral analysis

Representative folded spectrum

O/O= 1.0 ± 0.1

Ne/Ne = 1.7 ± 0.2

Fe/Fe = 0.39 ± 0.05

All spectra are well described by two MEKAL components


Shock cloud interaction in the vela snr the xmm newton view

TII (106 K)

TI (106 K)

cnt/s

The values of the temperature of both components don’t show significant variations in the field of view.


Shock cloud interaction in the vela snr the xmm newton view

nII2LII (1017 cm-5)

nI2LI (1017 cm-5)

cnt/s

For both components the product n2L (where n is the particle density and

L is the extension along the line of sight) presents huge inhomogeneities

in the field of view.


Shock cloud interaction in the vela snr the xmm newton view

Evolution of the shocked clouds

n = 0.5  1.9 cm-3

T  3.0  106 K

Corona:

trad> tcond

Evaporation

Collapse

n = 3.2  8.2 cm-3

T = 3  10  104 K

Optical filament:

n = 1.4  5 cm-3

T  1.14  106 K

Core:

trad< tcond

n < 0.07 cm-3

Intercloud medium:

T = 4  8  106 K

trad> tcond


Conclusions

cores: radiative cooling collapse

coronae: thermal conduction evaporation

Conclusions:

  • We resolved different phases in ISM clouds.

  • 3-D map of the observed clouds

    (FilD mass  1031g for a core particle density of 2 cm-3).

  • Discriminate model (no reflected shocks).

  • Evolution of the

    shocked clouds


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