# Presentation: 608308

## Observing Solar Wind Charge Exchange from a Coronal Mass Ejection

- David Henley
- &
- Robin Shelton

## Outline

*Observing SWCX from a Coronal Mass Ejection*

- Shadowing using a nearby absorbing filament
- Comparing *XMM* and *Suzaku *results:
*XMM *observations of the filament
*Suzaku* observations from the same directions
- Different results → SWCX emission in the *XMM* spectra
- Comparing observations with heliospheric SWCX models
- SWCX emission from a coronal mass ejection
- Summary

## Shadowing Observations of the Soft X-ray Background

*Observing SWCX from a Coronal Mass Ejection*

- Original goal: measure spectrum of LB and halo
- Constrain *kT*, ionization state, abundances
- Use shadowing filament at b ~ –45°
*d *= 230 pc
*XMM *&* Suzaku* observations on and off filament

- Grayscale: *ROSAT* 1/4 keV
- Contours:  *IRAS* 100 micron

## XMM-Newton Spectra(Henley, Shelton & Kuntz 2007)

*Observing SWCX from a Coronal Mass Ejection*

*XMM-Newton* Spectra(Henley, Shelton & Kuntz 2007)

- No unusual features in SW data
- No flares
- SW data at or below typical values
- Did not expect significant SWCX contamination

## XMM-Newton Spectra(Henley, Shelton & Kuntz 2007)

*Observing SWCX from a Coronal Mass Ejection*

*XMM-Newton* Spectra(Henley, Shelton & Kuntz 2007)

- Spectral model:
- LB + e-τ (Halo + Extragalactic)
- Include RASS data
- Need 2 halo components
-  		log *T* (K)	E.M. (cm-6 pc)
- LB	6.06		0.018
- Halo	5.93		0.17
- 6.43		0.011
- Reasonable agreement with previous studies

## Suzaku Spectra(Henley & Shelton 2008)

*Observing SWCX from a Coronal Mass Ejection*

*Suzaku* Spectra(Henley & Shelton 2008)

-  		log *T* (K)	E.M. (cm-6 pc)
- LB	5.98		0.0064
- Halo	6.11		0.035
- 6.50		0.0065
- Compare with *XMM*:
- LB	6.06		0.018
- Halo	5.93		0.17
- 6.43		0.011
- Different codes used:
*XMM*: APEC for everything
*Suzaku*: RS for *ROSAT* 1/4 keV

## Suzaku Spectra(Henley & Shelton 2008)

*Observing SWCX from a Coronal Mass Ejection*

*Suzaku* Spectra(Henley & Shelton 2008)

-  	log *T* (K)	E.M. (cm-6 pc)
- LB	5.98		0.0064
- Halo	6.11		0.035
- 6.50		0.0065
- Compare with *XMM*:
- LB	6.06 	6.30	0.018	0.013
- Halo	5.93 	5.73	0.17	0.16
- 6.43 	6.56	0.011	0.0038
- Re-doing the *XMM* analysis does not get rid of the discrepancy

## SWCX Emission in XMM Spectra

*Observing SWCX from a Coronal Mass Ejection*

- SWCX Emission in *XMM* Spectra

- Extra emission component in *XMM* spectra               (in addition to LB, halo, extragalactic background)
- Solar wind charge exchange emission

- On filament *XMM* spectrum
- (MOS1 & MOS2)

- Best-fitting
*Suzaku* model

- O VII
- 3.8 ± 0.5 L.U.

- O VIII
- 1.4 ± 0.3 L.U.

## Koutroumpa et al. model takes into account solar cycle variations
More O+7, O+8 ions along sight-line at solar max than at solar min
Model predicts higher O VII & O VIII fluxes for XMM (solar max) than Suzaku (solar min)
“Ground level” model underpredicts XMM intensities:

*Observing SWCX from a Coronal Mass Ejection*

- Koutroumpa et al. model takes into account solar cycle variations
- More O+7, O+8 ions along sight-line at solar max than at solar min
- Model predicts higher O VII & O VIII fluxes for *XMM* (solar max) than *Suzaku* (solar min)
- “Ground level” model underpredicts *XMM* intensities:

- Comparing Observations with Heliospheric SWCX Models

**Solar max (*****XMM*****)**

**Solar min (*****Suzaku*****)**

- 					**O VII **(L.U)**	****O VIII **(L.U.)
- Observed *XMM* excesses:		3.8 ± 0.5	1.4 ± 0.3
- Koutroumpa et al. (2007):		2.32		0.92

## SWCX emission from a Coronal Mass Ejection (CME)

*Observing SWCX from a Coronal Mass Ejection*

- Excesses in *XMM* spectra may be partly due to localized SW enhancement moving across sight-line
- CME emitted ~2.5 days before *XMM* observations (Koutroumpa et al. 2007)

## SWCX emission from a Coronal Mass Ejection (CME)

*Observing SWCX from a Coronal Mass Ejection*

- Excesses in *XMM* spectra may be partly due to localized SW enhancement moving across sight-line
- CME emitted ~2.5 days before *XMM* observations (Koutroumpa et al. 2007)

- Differences between *XMM* and *Suzaku *yield SWCX spectrum of a CME
- Could be used to probe composition of CMEs

## Looking for Indications of SWCX in ACE Data

*Observing SWCX from a Coronal Mass Ejection*

- Looking for Indications of SWCX in *ACE *Data

*ACE* data: no indication that *XMM* spectra were contaminated
- In general, CMEs will not be seen in *ACE* data
- Simply inspecting *ACE* data may be inadequate for determining if SWCX is contaminating a X-ray b/g spectrum

*XMM*

*Suzaku*

## Summary

*Observing SWCX from a Coronal Mass Ejection*

*XMM* and *Suzaku* shadowing observations of absorbing filament yielded different results
*XMM* spectra are contaminated by SWCX emission
- Emission probably due to CME moving across sight-line
- Differences between spectra yield SWCX spectrum of a CME
- Contamination not identified in original *XMM* analysis
- No indication of SWCX contamination from *ACE* data
- Contamination unapparent till we compared with *Suzaku*
- Inspecting *ACE* data may be inadequate for identifying SWCX contamination
- Multiple observations essential
*Reference: Henley & Shelton, 2008, ApJ, 676, 335*