Paper I Reference paper: "Synthetic spectra of H Balmer and HeI absorption lines. I: Stellar Library" by Rosa M. Gonzalez Delgado & Claus Leitherer. 1999, ApJS, accepted Abstract: We present a grid of synthetic profiles of stellar H Balmer and HeI lines at optical wavelengths with a sampling of 0.3 \AA. The grid spans a range of effective temperature (Teff) between 50000 K and 4000 K, and gravity (log g) between 0.0 and 5.0 at solar metallicity. For Teff>25000 K, NLTE stellar atmosphere models are computed using the code TLUSTY (Hubeny 1988). For cooler stars, Kurucz (1993) LTE models are used to compute the synthetic spectra. The grid includes the profiles of the high-order hydrogen Balmer series and HeI lines for effective temperatures and gravities that have not been previously synthesized. The behavior of H8 to H13 and HeI 3819 with effective temperature and gravity is very similar to that of the lower terms of the series (e.g. Hbeta) and the other HeI lines at longer wavelengths; therefore, they are suited for the determination of the atmospheric parameters of stars. These lines are potentially important to make predictions for these stellar absorption features in galaxies with active star formation. Evolutionary synthesis models of these lines for starburst and post-starburst galaxies are presented in a companion paper. The full set of the synthetic stellar spectra is available for retrieval at our websites http://www.iaa.es/ae/e2.html and http://www.stsci.edu/science/starburst/ or on request from the authors at rosa@iaa.es. The spectral ranges synthesized (Table 1 of the paper) are: RANGE MAIN LINES IN RANGE --------- --------------------------- 3720-3920 H13, H12, H11, H10, HeI 3819, H9, H8 3990-4150 HeI 4009, HeI 4026, Hd, HeI 4121, HeI 4144 4300-4400 Hg, HeI 4388 4420-4550 HeI 4471 4820-4900 Hb 4900-4950 HeI 4922 The grid of models is in Table 2 of the paper. Files on this website: 1. The stellar library is in the gziped tar file: library.tar.gz This tar file contains the synthetic spectra with effective temperature between 50000 K and 4000 K, and gravity (log g) between 0.0 and 5.0 at solar metallicity in the files (one for each of the above wavelength ranges): L1.dat, L2.dat, L3.dat, L4.dat, L5.dat and L6.dat Column 1: Effective temperature ( from 4000 K to 50000 K) Column 2: wavelength (in Angstroms) Column 3-13: normalized spectrum for log g= 5.0, 4.5, 4.0, 3.5, 3.0, 2.5, 2.0, 1.5, 1.0, 0.5 and 0.0, respectively. 2. The equivalent width measurements are in: Ew-stars.tar.gz The equivalent widths of the lines were measured in the spectral windows defined as follows:: Line Line window Continuum window H10 3783-3813 1 H9 3823-3853 1 H8 3874-3904 1 Hd 4070-4130 2 Hg 4311-4371 3 Hb 4830-4890 4 HeI 3819 3816-3823 1 HeI 4026 4020-4031 2 HeI 4388 4381-4395 3 HeI 4471 4464-4478 5 HeI 4922 4915-4929 6 The pseudo-continuum was determined by fitting a first order polynomial (except for the spectral range 3700-3900 A, for which we used a third order) to the windows defined as: (1): 3726-3729, 3740-3743, 3760-3762, 3782-3785, 3811-3812, 3869-3870, 3909-3911. (2): 4019-4020, 4037-4038, 4060-4061, 4138-4140, 4148-4150. (3): 4301-4305, 4310-4312, 4316-4318, 4377-4381, 4392-4394, 4397-4398. (4): 4820-4830, 4890-4900. (5): 4439-4440, 4445-4446, 4478-4479, 4503-4506. (6): 4900-4902, 4905-4906, 4915-4916, 4928-4929, 4948-4950. The tar gziped files contain the equivalent width of the Balmer lines (Hb, Hd and H8) and HeI lines (3819, 4026, 4388, 4471 and 4922): Ew-Hb.tab, Ew-Hd.tab, Ew-H8.tab Ew-He3819.tab, Ew-He4026.tab, Ew-He4388.tab, Ew-4471.tab, Ew-4922.tab Column 1: effective temperature Column 2-9: Equivalent width of stars with gravity, log g = 5.0, 4.5, 4.0, 3.5, 3.0, 2.5, 2.0, 1.5. ******************************************************************************* Paper II Reference paper: "Synthetic spectra of H Balmer and HeI absorption lines. II: Evolutionary synthesis models for starburst and post-starburst galaxies." by Rosa M. Gonzalez Delgado, Claus Leitherer, & Timothy Heckman. 1999, ApJS, accepted Abstract: We present evolutionary stellar population synthesis models to predict the spectrum of a single-metallicity stellar population, with a spectral sampling of 0.3 Angstroms in five spectral regions between 3700 A and 5000 A. The models, which are optimized for galaxies with active star formation, synthesize the profiles of the hydrogen Balmer series (Hbeta, Hgamma, Hdelta, H8, H9, H10, H11, H12 and H13) and the neutral helium absorption lines (HeI 4922, HeI 4471, HeI 4388, HeI 4144, HeI 4121, HeI 4026, HeI 4009 and HeI 3819) for a burst with an age ranging from 1 Myr to 1 Gyr, and different assumptions about the stellar initial mass function (IMF). Continuous star formation models lasting for 1 Gyr are also presented. The input stellar library includes NLTE absorption profiles for stars hotter than 25000 K and LTE profiles for lower temperatures. The temperature and gravity coverage is 4000 K