Evolution of close binaries after the burst of starformation for different IMFs

S. B. Popov; V. M. Lipunov; M. E. Prokhorov; K. A. Postnov

paper

Evolution of close binaries after the burst of starformation for different IMFs

arXiv:astro-ph/9711352

Abstract

We use "Scenario Machine" -- the population synthesis simulator -- to calculate the evolution of populations of selected types of X-ray sources after a starformation burst with the total mass in binaries (1--1.5) \cdot 10^6 M_{\odot} $d u r in g t h e f i r s t 20 M y r a f t er ab u r s t . W e p r ese n t h er e t h er es u l t so f tw ose t so f r u n so f t h e p r o g r am . I n t h e f i r s t se tw ee x amin e d t h e f o l l o w in g t y p eso f c l ose bina r i es : t r an s i e n t so u r ces - - n e u t r o n s t a r s w i t h B e - s t a r s; ‘‘ X - r a y p u l s a r s^{''} - - n e u t r o n s t a r s in p ai r s w i t h s u p er g ian t s; C y g X - 1 - l ik eso u r ces - - b l a c k h o l es w i t h s u p er g ian t s; ‘‘ S S 443 - l ik eso u r ce s^{''} - - s u p er a ccr e t in g b l a c k h o l es . W e u se d tw o v a l u eso f t h ee x p o n e n t$ α $in t h e ini t ia l ma ss f u n c t i o n : 2.35 (S a l p e t e r^{'} s f u n c t i o n) an d 1 (‘‘ f l a t s p ec t r u m^{''}) . T h ec a l c u l a t i o n s w er e ma d e f or t h e f o l o w in g v a l u eso f t h e u pp er l imi t o f t h e ma ss f u n c t i o n : 120 an d 30$ M_{\odot} $. F or t h e ‘‘ f l a t s p ec t r u m^{''}, s ug g es t e d in (C o n t ini e t a l, 1995), t h e n u mb er o f so u r ceso f a l l t y p ess i g ni f i c an tl y in cr e a se d . W i t h t h e ‘‘ f l a t s p ec t r u m^{''} an d w i t h t h e u pp er ma ss l imi t 120$ M_{\odot} $w eo b t ain e d h u n d r e d so f so u r ceso f a l l c a l c u l a t e d t y p es . D ecr e a s in g o f t h e u pp er ma ss l imi t b e l o w t h ecr i t i c a l ma sso f ab l a c k h o l e f or ma t i o nin cr e a se t h e n u mb er o f t r an s i e n t so u r ces w i t hn e u t r o n s t a r s u pt o$ \approx 300 $. I n t h eseco n d se tw ee x amin e d t h ee v o l u t i o n o f o f 12 o t h er t y p eso f X - r a y so u r ces f or$ α=1 $,$ α=1.35 $an d$ α=2.35 $an df or t h r ee u pp er ma ss l imi t s : 120$ M_{\odot} $, 60$ M_{\odot} $, 40$ M_{\odot}$ (see Perez-Olia & Colina 1995 for the reasons for such upper limits) on the same time scale 20 Myr after a star formation burst.

12 pages, 4 PostScript figures, to be presented as a poster at the conference "Cosmology: from COBE to galaxy formation", 1-7 December 1997, Copenhagen