English

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

Astrophysics 2007-05-23 v1

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}duringthefirst20Myrafteraburst.Wepresentheretheresultsoftwosetsofrunsoftheprogram.Inthefirstsetweexaminedthefollowingtypesofclosebinaries:transientsourcesneutronstarswithBestars;Xraypulsarsneutronstarsinpairswithsupergiants;CygX1likesourcesblackholeswithsupergiants;SS443likesourcessuperaccretingblackholes.Weusedtwovaluesoftheexponent during the first 20 Myr after a burst. We present here the results of two sets of runs of the program. In the first set we examined the following types of close binaries: transient sources-- neutron stars with Be- stars; ``X-ray pulsars''-- neutron stars in pairs with supergiants; Cyg X-1-like sources-- black holes with supergiants; ``SS443-like sources''-- superaccreting black holes. We used two values of the exponent \alphaintheinitialmassfunction:2.35(Salpetersfunction)and1(flatspectrum).Thecalculationsweremadeforthefolowingvaluesoftheupperlimitofthemassfunction:120and30 in the initial mass function: 2.35 (Salpeter's function) and 1 (``flat spectrum''). The calculations were made for the folowing values of the upper limit of the mass function: 120 and 30 M_{\odot}.Fortheflatspectrum,suggestedin(Continietal,1995),thenumberofsourcesofalltypessignificantlyincreased.Withtheflatspectrumandwiththeuppermasslimit120. For the ``flat spectrum'', suggested in (Contini et al, 1995), the number of sources of all types significantly increased. With the ``flat spectrum'' and with the upper mass limit 120 M_{\odot}weobtainedhundredsofsourcesofallcalculatedtypes.Decreasingoftheuppermasslimitbelowthecriticalmassofablackholeformationincreasethenumberoftransientsourceswithneutronstarsupto we obtained hundreds of sources of all calculated types. Decreasing of the upper mass limit below the critical mass of a black hole formation increase the number of transient sources with neutron stars up to \approx 300.Inthesecondsetweexaminedtheevolutionofof12othertypesofXraysourcesfor. In the second set we examined the evolution of of 12 other types of X-ray sources for \alpha=1,, \alpha=1.35and and \alpha=2.35andforthreeuppermasslimits:120 and for three upper mass limits: 120 M_{\odot},60, 60 M_{\odot},40, 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.

Keywords

Cite

@article{arxiv.astro-ph/9711352,
  title  = {Evolution of close binaries after the burst of starformation for different IMFs},
  author = {S. B. Popov and V. M. Lipunov and M. E. Prokhorov and K. A. Postnov},
  journal= {arXiv preprint arXiv:astro-ph/9711352},
  year   = {2007}
}

Comments

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