ZAATRI , A.

We have estimated the radial gradient of angular velocity in the near subsurface layers of the sun for the period 07/2001-07/2007 which covers 80 Carrington rotations, starts at the maximum of cycle 23 and ends at its minimum. This analysis confirms that, on average, the radial gradient of angular velocity remains negative and roughly constant...

Astrophysics and Space Science, p. 200 (2009)

Astronomy and Astrophysics, 504, pp. 589-594 (2009)

Astronomy and Astrophysics, 469, pp. 1145-1149, http://dx.doi.org./10.1051/0004-6361:7212

Solar Physics, 236, pp. 227-244, http://dx.doi.org./10.1007/s11207-006-0106-5

Mapping the solar surface is a crucial step in any local helioseismology technique. Because the acoustic waves propagate along great circles at the solar surface, it has been shown that these circles need to be used in the geometrical construction of the plane grid. We study different types of projections based on great circles for the...