Simulating M51's interaction history

(Durrell, Mihos, Feldmeier, Jacoby, & Ciardullo 2003)

M51 - The Whirlpool

One of the first objects simulated by Toomre & Toomre (1972), and simulated by several investigators since.

Toomre (1977): Recent single parabolic passage
Hernquist (1990): Time since passage longer to account for M51's extended HI tail.
Salo and Laurikainen (2000): Postulate a second encounter to account for kinematic structure in M51's disk.

Problem: Lack of kinematic information in NGC 5195's tidal debris.

Solution: Planetary Nebulae

(from Durrell etal 2003)

Studying the PN in M51:

KPNO 4m [OIII] imaging (Feldmeier, Ciardullo, and Jacoby 1997)
Followup WIYN spectra of PN candidates (Durrell etal 2003)

Two oddities:

Extended PN tail to the W of NGC 5195	Bimodal PN kinematics in the W tail
(from Feldmeier etal 1998)	(from Durrell etal 2003)

Dynamical Modeling of M51

(Durrell etal 2003)

Can we develop a model of the M51 system that explains the PNe kinematics using a single passage model?

Parabolic Encounter
Mass ratio: 2:1
T ~ 250 Myr past peri
NGC5194: (i,w)=(-70,0)
NGC5195: (i,w)=(110,-30)

Interaction Movie (normal)
Interaction Movie (deep imaging)