Synthetic Spectra of H Balmer and He I Absorption Lines. II. Evolutionary Synthesis Models for Starburst and Poststarburst Galaxies

摘要: We present evolutionary stellar population synthesis models to predict the spectrum of a single-metallicity population, with spectral sampling 0.3 A in five regions between 3700 and 5000 A. The models, which are optimized for galaxies active star formation, synthesize profiles hydrogen Balmer series (Hβ, Hγ, Hδ, H8, H9, H10, H11, H12, H13) neutral helium absorption lines (He I λ4922, He λ4471, λ4388, λ4144, λ4121, λ4026, λ4009, λ3819) burst an age ranging from 106 109 yr, different assumptions about initial mass function (IMF). Continuous formation lasting 1 Gyr also presented. input library includes non-LTE stars hotter than 25,000 K LTE lower temperatures. temperature gravity coverage is 4000 ≤ Teff 50,000 0.0 log g 5.0, respectively. metallicity solar. It found that line sensitive age, except during first 4 Myr evolution, when equivalent widths these constant. At early stages IMF. However, strong H predicted even low-mass cutoff IMF as high 10 M☉. range 2 16 those 0.2 1.2 During nebular phase (cluster younger Myr), Hβ ranges 5 λ4471 0.5 strength maximum cluster few hundred (for lines) tens old. In continuous scenario, increases monotonically time until 500 100 Myr, weaker owing dilution by contribution very massive stars. resolution useful reproduce wings observed recent estimate effect underlying on emission lines. compared components indicates Hδ higher order terms dominated component if instantaneous older Myr. Some (e.g., λ3819 λ4922) more favorable others λ4471) detection features presence emission. correction due 5% 25%, has width 2.5 (corresponding 3 Myr). can be used date starburst poststarburst Gyr. They have been tested data clusters LMC, super-star B galaxy NGC 1569, nucleus dwarf elliptical 205 luminous "E+A" galaxy. full set available retrieval at our websites or request authors.