NSO/T Scientific Staff
Areas of Interest
Global and Local Helioseismology, Image Restoration, Data Analysis Techniques
Recent Research Results
Toner, S. Jefferies, and T. Toutain (Observatoire de Nice) have confirmed the
prediction (T. Toutain, G. Berthomieu, and J. Provost, 1999, Astronomy &
Astrophysics, 344, 188)
that the p-mode amplitude in the continuum peaks very near the solar limb.
They also found
that the low-frequency solar background decreases at the limb. The
combination of low
background and high oscillation signal makes the solar limb an ideal place to
look for low-frequency oscillations such as g-modes. The detection of solar g-modes would substantially
increase our knowledge of the deep solar interior.
Toner, S. Jefferies, R. Garcia (Service d'Astrophysique, France), and P.
Palle (Instituto da
Astrofisica de Canarias, Spain) have developed a data analysis technique
substantially increase the signal-to-noise ratio in solar oscillation spectra
by reducing the
contamination due to incoherent noise. This allows more precise measurements
oscillation parameters (e.g. frequency, line width, etc.) and has allowed the
detection of modes
that previously were lost in the background noise.
Toner has been developing an algorithm for merging GONG data at the image
level . This is in
preparation for the upgrade of the GONG instruments to higher resolution
so that the Project can begin using GONG data for local helioseismology.
Future Research Plan
With the confirmation that the p-mode amplitude peaks at the solar limb,
combined with the
discovery that the low-frequency solar background decreases at the limb,
Toner has obtained
sixty days of full-disk solar intensity images (recorded by the MDI
instrumention board the
SOHO spacecraft) which he will analyse to look for g-modes. Toner will
continue to work on
the image merge algorithm for GONG and adapt donated routines for the "local"
GONG+ data. He also plans to investigate the phase relation between intensity
oscillations locally on the Sun, rather than globally.
Toner performs observatory service as Assistant Data Scientist for the GONG
project. He is also
involved in the NOAO Educational Outreach Program, having given talks and
at schools and at Boy/Cub Scout functions.