AAS 204th Meeting, June 2004
Session 42 Cosmology and Lensing
Poster, Tuesday, June 1, 2004, 10:00am-7:00pm, Ballroom

## [42.06] Lensing Effects on the Brightness of SN Ia, When Using the Sinusoidal Potential.

M.J. Dadras, D.F. Bartlett (Physics, U. Colorado), P. Motl (CASA, U. Colorado)

In this paper the effects of gravitational lensing of SN Ia are studied, for the case when the Newtonian potential is replaced by the sinusoidal potential (GM/r \to (GM cos[kr])/r). First we treat the point-mass case, then move on to the instance of a diffuse mass.

As one might guess, with this new potential, the plot of the bending angle (\alpha) with respect to impact parameter (b) goes from dropping off as b-1, to having oscillations that die off as the b-1/2. This in turn will cause dramatic effects on magnification and brightness.

In principle the value of the cosmological deceleration parameter (q0), can be determined by a measurement of the ratio of \alpha to b. Wambsganss et al (1997) and Holz (1998) discussed the effects of weak gravitational lensing from large-scale structure on determining q0 within standard cosmology. Following their reasoning, we extend that work to the case of the sinusoidal potential.

Bulletin of the American Astronomical Society, 36 #2
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