The 'cetus_stream_model.txt' contains the most favorable N-body model of the 
Cetus Stream system (D20, O2, P8) from Chang & Yuan etal, 2020.

This model contains 2e5 Star Particles with mass of 1000 Msun.
The 'cetus_stream_model.txt' contains the following columns:
1-2:	Ra, Dec 	- ICRS celestial coordinates [degree]
3-4:	l, b		- Galactic coordinate [degree]
5:		dis			- Heliocentric distance [kpc]
6:		vlos		- line-of-sight velocity [km/s]
7-8:	pmra, pmdec	- proper motions [mas/yr]
9-10:	pmll, pmbb	- proper motions [mas/yr]
11-13:	x, y, z		- position in the Galactocentric cartesian coordinate system[kpc]
14-16:	vx, vy, vz	- velocity [km/s]
17:		psi			- orbital azimuthal angle [degree], the center of the progenitor remnant (if exist) is 0, >0 is the leading arm, <0 is the trailing arm, details please refer to Chang & Yuan etal, 2020.

1. Solar distance to the Galactic center and the LSR velocity are set to 8 kpc and 232 km/s, 
solar peculiar motion (U, V, W) = (11.1, 12.24, 7.25) km/s with respect to the LSR (Schonrich+2010).

2. The center of the disrupted progenitor (if still exist) is located at (x, y, z) = (-8.83, 1.44, 14.31) kpc, 
with motion (vx, vy, vz) = (-164.98, -209.83, 28.16) km/s, in the Galactocentric cartesian coordinate.

3. Selection of the wraps (L1, T1, T2) in Yuan et al 2021:   
	ind_l1 = (s['psi'] > 0) * (s['psi'] < 260)   
	ind_t1 = (s['psi'] > -300) * (s['psi'] < 0)
	ind_t2 = (s['psi'] > -600) * (s['psi'] < -300)   
