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Insights into Galactic Magnetic Field Evolution from International Survey

This study presents observations of the Galactic magnetic field from the International Galactic Plane Survey, showcasing field concentration in the disk, spiral arm alignment, and more. It explores field reversals and implications for field evolution.

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Insights into Galactic Magnetic Field Evolution from International Survey

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  1. Observations of the Galactic Magnetic Field from the International Galactic Plane Survey Jo-Anne Brown

  2. People SGPS CGPS • Russ Taylor • Tom Landecker • Andrew Gray • Rob Reid • Roland Kothes • Dave Delrizzo • Bulent Uyaniker • Marta Peracaula • Marijke Haverkorn • Bryan Gaensler • Natalya Bizunok • Naomi McClure-Griffiths • John Dickey • Anne Green

  3. People SGPS CGPS • Russ Taylor • Tom Landecker • Andrew Gray • Rob Reid • Roland Kothes • Dave Delrizzo • Bulent Uyaniker • Marta Peracaula • Marijke Haverkorn • Bryan Gaensler • Natalya Bizunok • Naomi McClure-Griffiths • John Dickey • Anne Green

  4. Outline • Introduction • Observations: CGPS • Observations: SGPS • Summary

  5. The Galactic Magnetic Field • field is concentrated in disk • follows the spiral arms • local field is cw • Sagittarius field is ccw • additional reversals unclear • Determining the location of reversals may help understand the evolution of the field.

  6. Faraday Rotation

  7. Probes of the Field EGS Pulsars

  8. Compact Polarised Sources Pulsars: 529

  9. Compact Polarised Sources Pulsars: 529 EGS: 887 First Large Catalog of EGS (555 sources): Simard-Normandin, M, P. P. Kronberg, Button, S (1981) ApJS, 45, 91

  10. Low-latitude Polarised Sources Pulsars: 375 EGS: 121

  11. Low-latitude Polarised Sources Pulsars: 375 EGS: 121 CGPS SGPS

  12. Observations

  13. Canadian Galactic Plane Survey Pilot Project (PhD): Magdalen Normandeau

  14. CGPS Region: Pulsars and EGS

  15. CGPS Region: Pulsars and EGS

  16. Science with the CGPS • Field Alignment with the spiral arms • Reversals in the outer Galaxy • Small-scale field correlation with the large-scale field. • Latitude Dependence

  17. Science with the CGPS • Field Alignment with the spiral arms • Reversals in the outer Galaxy • Small-scale field correlation with the large-scale field. • Latitude Dependence

  18. Appropriate Longitude Range 135o 105o

  19. Previous Studies Data ranges: Lyne & Smith (1989):105o < l < 135o, |b| < 30o Han et al. (1999): 104o < l < 119o, |b| < 30o

  20. Path Length Comparison

  21. CGPS for 105o < l < 135o

  22. Combining Pulsars with CGPS EGS: No detectable magnetic field reversal in the outer Galaxy. Published: ApJ, 592:L29-L32, July 2003

  23. Science with the CGPS • Field Alignment with the spiral arms • Reversals in the outer Galaxy • Small-scale field correlation with the large-scale field. • Latitude Dependence

  24. CGPS Region: Pulsars and EGS

  25. RM vs Latitude

  26. RM vs Latitude

  27. Calculating the Scale Height

  28. Calculating the Scale Height

  29. Southern Galactic Plane Survey PhD Thesis: Naomi Mclure-Griffiths

  30. SGPS Region: Pulsars and EGS

  31. SGPS Region: Pulsars and EGS

  32. Comparing CGPS and SGPS

  33. RM vs Longitude: SGPS

  34. RM Modulation by Spiral Arms

  35. Binned CGPS RMs over Stokes I Binsize: 3oStepsize: 0.5o

  36. Summary • IGPS has yielded much needed EG RMs - 1078 (so far) in CGPS I,II,III - 149 in SGPS (depolarization) • No B-Field reversals in the Outer Galaxy • Rough calculations show magneto-ionic scale height of ~1.2 kpc at l=110o • RM “oscillations” may correlate with HII or arms

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