Star formation

From: Fabrice DURIER <Fabrice.DURIER_at_obs-nice.fr>
Date: Sat, 12 Nov 2005 12:50:58 +0100

Dear all,

  Presently, I'm trying to introduce a mechanism to form stars on
Gadget1 (unfortunately Gadget2 does not work yet on our Alpha machine:
it compiles with mpich1.2.6 but crashes after a few steps without any
particular error message, just p0_882848: p4_error: interrupt SIGFPE: 8...)

  Anyway, I have already put a cooling function (Katz, Weinberg &
Hernquist, 96) in the energy equation for gas particles. I select
particles which satisfy specific conditions (in the usual way: Jeans
instability, density threshold...). I then switch these particles from
type 0 to type 4.

  As I have seen previous messages here on this subject, I wanted to
follow Volker's advice: to insert a "rearrange_particle" routine just
before the domain decomposition, but the code crashes immediately after.
Without this routine, the code continue with the following warning
sometimes appearing after the "birth" of a star:

    Warning. No convergence in `findSplitPoint' achieved.
    Balance: 0.469157 Iterations: 128 Task: 0
    flagmemoryimbalance=0
    xmaxleftofguess=14535.1 xminrightofguess=14856.6 xleft=14856.6
xright=14856.6

  I found the function findSplitPoint() in the file domain.c, but does
anyone know what it means?

  My main problem however concern the feedback model. During the star
formation process, I need to "temporarily" remove some of the particles
(they must reappear later) of the simulation. I know Eugene Kurbatov
tried to introduce a negative type, but this seems too complicated to me
(I don't know how to modify the tree structure...). As a result, I put
Mass=0 for these gas particles (in the hope of later regaining mass),
but I'm not sure if the simulation treats them as "invisible". For the
moment I can't work out how to make them reappear!

Does anyone know how to do this? Any advice or idea would be appreciated!
Cheers,

Fabrice_
-- 
-------------------------------
 Fabrice Durier
 Observatoire de la Côte d'Azur
 Département CASSIOPEE
 B.P. 4229
 06304 NICE Cedex 04
 T: (+33) 04.92.00.31.91
 M:       06.22.12.28.88
 E-mail: durier_at_obs-nice.fr <mailto:durier_at_obs-nice.fr>
-------------------------------
Received on 2005-11-12 13:00:35

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