1 / 13

Observing Solar Wind Charge Exchange from a Coronal Mass Ejection

David Henley & Robin Shelton. Observing Solar Wind Charge Exchange from a Coronal Mass Ejection. Outline. Shadowing using a nearby absorbing filament Comparing XMM and Suzaku results: XMM observations of the filament Suzaku observations from the same directions

xantha-cleveland
Download Presentation

Observing Solar Wind Charge Exchange from a Coronal Mass Ejection

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. David Henley & Robin Shelton Observing Solar Wind Charge Exchange from a Coronal Mass Ejection

  2. Observing SWCX from a Coronal Mass Ejection Outline • 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

  3. Observing SWCX from a Coronal Mass Ejection Shadowing Observations of the Soft X-ray Background • 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

  4. 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

  5. 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

  6. 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

  7. 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

  8. Observing SWCX from a Coronal Mass Ejection SWCX Emission in XMM Spectra O VII 3.8 ± 0.5 L.U. • Extra emission component in XMM spectra (in addition to LB, halo, extragalactic background) • Solar wind charge exchange emission On filament XMM spectrum (MOS1 & MOS2) O VIII 1.4 ± 0.3 L.U. Best-fitting Suzaku model

  9. Observing SWCX from a Coronal Mass Ejection Comparing Observations with Heliospheric SWCX Models • 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: 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

  10. Observing SWCX from a Coronal Mass Ejection SWCX emission from a Coronal Mass Ejection (CME) • 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)

  11. Observing SWCX from a Coronal Mass Ejection SWCX emission from a Coronal Mass Ejection (CME) 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

  12. 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 Suzaku XMM

  13. Observing SWCX from a Coronal Mass Ejection Summary 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

More Related