THIS README DESCRIBES THE FILES CONTAINING THE STELLAR POPULATION MODELS OF MARASTON & STROMBACK (2011, MNRAS). MODELS ARE AVAILABLE AT WWW.MARASTON.EU/M11/. These models have the same stellar energetics and atmospheric parameters as the standard Maraston (2005, M05) models. The difference is in the individual stellar spectra that are assigned to the various synthetic stars according to their effective temperatures and gravities (Teff and log). These spectra can be either empirical or theoretical, and in some cases a mixture of them. In particular, the empirically-based models have been extended in wavelength coverage into the UV, using the high-resolution models published in Maraston et al. (2009, 493, 425), which are based on the theoretical spectral library UVBLUE (Rodrigues-Merino et al. 2005). This extension was made at various metallicities in case of the MILES-based models, and at solar metallicity for STELIB and ELODIE. The UV-extended models will be indicated using the addition 'UVextended' to the file name (see below). We also provide a version of the Pickles-based models, which extend to the UV, using the models with the theoretical UV. In this case since is not an extension we call then 'UVtheoretical'. In general, models should be chosen according to the spectral resolution that is needed by observations, though differences induced by the use of different spectral libraries exist. See the paper for a description or contact the authors. The webpage contains: -- Simple Stellar Population models (SSPs) as a function of age, metallicity, IMF and stellar library. FILES: SSP_M11_ELODIE.tar.gz, SSP_M11_Pickles.tar.gz, SSP_M11_STELIB.tar.gz, SSP_M11_MILES.tar.gz, SSP_M11_MARCS.tar.gz These models are extensively described in 1., see below. -- Selected SSPs (MILES and STELIB-based) in ASCII format as in the Bruzual & Charlot models FILE: M11_BCformat.tar.gz. A README is included -- Composite models, i.e. models with extended star formation using the SSP highres as model unit. ** LRG best fit model. This model was published in Maraston et al. 2009, MNRAS, 394, 107. It is a composite population made of 97% by mass solar-metallicity stars and 3% by mass metal-poor stars with the same age. It was found to give a good fit to the median colours of Luminous Red Galaxies at redshift between 0.4 and 0.7. Here we provide the same type of model using the high-resolution SSPs. FILE: CSP_LRG_highres.tar.gz ** More composite models will be made available at a later stage. ******************************* 1. NOTATIONS OF SSPs ********************************************* GENERAL NAMING: ------------------------------------------------------------------------------ ssp_M11'_'library'_'any eventual extension'.'imf''zxxx'.'HB morphology': ------------------------------------------------------------------------------ * 'ssp_M11': Simple Stellar Populations by Maraston & Stromback 2011 * 'library': reference to the adopted stellar library, e.g. Pickles, MILES, STELIB, ELODIE, MARCS, see below for a detailed description. * 'any eventual extension': it refers to whether the models have been extended in wavelength coverage by merging with other models or have been revised with respect to the original library. Cases are: 'UVextended': models extended into the UV by merging with theoretically-based SSPs 'UVtheoretical': only for Pickles-based models. The Pickles-based UV as been substituted with the theoretical UV 'nearIRextended': 'revisednearIRslope': only for MILES-based models of solar metallicity. The slope of the models longward 6000 AA has been slightly revised as described in the Appendix of the paper. * 'imf': Initial Mass Funcion,IMF, namely: '.ss' ==> Salpeter IMF '.kr' ==> Kroupa IMF '.cha' ==> Chabrier IMF (Other IMFs could be obtained contacting the authors) * 'zxxx': chemical composition, as it follows (notation identical to M05) z10m4=0.0001 z0001=0.001 z001=0.01 z002=0.02 (solar metallicity) z004=0.04 * 'Horizontal Branch morphology': following the notation of M05 this can be rhb=intermediate-red and bhb=intermediate-blue. Relevant to sub-solar metallicities. COLUMNS: ------------------------------------------------------------------------------ Age (Gyr) | [Fe/H] | Wavelength (AA) | Flux (ergs /s /AA /Msun) | ------------------------------------------------------------------------------ Fluxes are normalised to 1 Msun. -------------------------------------------------- DESCRIPTION OF MODELS BASED ON EMPIRICAL LIBRARIES -------------------------------------------------- PICKLES-BASED MODELS: These models are based on the stellar library by Pickles (1998). * Models can be calculated only for solar metallicity. * Available in a purely empirical version and in an near-IR-extended version where the M-giants are semi-empirical at wavelengths shorter than 10000 AA, and purely synthetic red-wards of this. Notation: 'Pickles-ext'. * TP-AGB spectra are used at original resolution, which is higher than the Pickles resolution. * O-type spectra are affected by dust attenuation in the UV, which affects the youngest ages (see paper for details). * A version of the model was calculated in which the UV spectrum is based on theoretical models. Notation: 'UVtheoretical' Resolution: R~500 5.0 AA sampling -------------------------------------------------------------------------------------------------- ssp_M11_Pickles.'imf'z002: 58 ages, 2.5 Myr to 15 Gyr 1150.0 - 10620 AA 1895 flux points ssp_M11_Pickles_nearIRextended.'imf'z002: 58 ages, 2.5 Myr to 15 Gyr 1150.0 - 25000 AA 4771 flux points ssp_M11_Pickles_UVtheoretical.ssz002: 55 ages, 2.5 Myr to 12 Gyr 1005.0 - 10620 AA 1924 flux points UV based on theoretical models, merging around 3750 AA. ssp_M11_Pickles_UVtheoretical_nearIRextended.'imf'z002: 55 ages, 2.5 Myr to 12 Gyr 1005.0 - 25000 AA 4800 flux points UV based on theoretical models merging around 3750 AA. -------------------------------------------------------------------------------------------------- STELIB-BASED MODELS: These models are based on the stellar library STELIB by Le Borgne et al. (2003). * Cool high-resolution theoretical stars (Gustafsson et al. 2008) have been added to counter inadequacies in the STELIB library. * Many spectra in the library are not complete over the quoted wavelength range, which limits the actual wavelength range of the youngest ages at solar, and all ages at non-solar metallicities. * Somewhat coarse sampling of stellar parameter space at non-solar metallicities may affect the reliability of these models. Resolution: 3.1-3.4 AA (fwhm) 0.5 AA sampling ssp_M11_STELIB.'imf'z001: 24 ages, 200 Myr to 15 Gyr 3201.0 - 9296.5 AA 12192 flux points !Usable wavelength range for all ages is 3201.0 - 7900.0 AA! ssp_M11_STELIB_UVextended.ssz001: 21 ages, 200 Myr to 12 Gyr 1001.0 - 9296.5 AA 16952 flux points !Usable wavelength range for all ages is 1001.0 - 7900.0 AA! ssp_M11_STELIB.'imf'z002: 39 ages, 30 Myr to 15 Gyr 3201.0 - 9296.5 AA 12192 flux points ssp_M11_STELIB_UVextended.ssz002: 36 ages, 30 Myr to 12 Gyr 1001.0 - 9296.5 AA 16592 flux points UV-extended version, models merged around 3750 AA. ssp_M11_STELIB.'imf'z004: 22 ages, 400 Myr to 15 Gyr 3201.0 - 9296.5 AA 12192 flux points !Usable wavelength range for all ages is 3201.0 - 7900.0 AA! ssp_M11_STELIB_UVextended.ssz004: 18 ages, 400 Myr to 12 Gyr 1001.0 - 9296.5 AA 16952 flux points !Usable wavelength range for all ages is 1001.0 - 7900.0 AA! -------------------------------------------------------------------------------------------------- MILES-BASED MODELS: These models are based on the stellar library MILES by Sanchez-Blazquez et al. (2006). * A few cool, high-resolution theoretical stars (Gustafsson et al. 2008) have been added for completeness. * Fairly poor sampling of stellar parameter space at the lowest metallicity may affect the reliability of these models. * We make two versions of solar metallicity models, one based on the MILES library as it is, and another one in which we revised the slope longward 6000 based on the finding that the slope of the MILES stellar spectra at the reddest lambdas is steeper (i.e. less flux) than the one of other libraries, which we figured out to be related to the assumed temperature calibration for RGB stars in MILES (Maraston & Stromback 2011). This manipulated model version is indicated as 'revised'. Its merit with respect to the standard model needs to be assessed through comparison with data (future work). * The actual spectral resolution of MILES has been determined in Beifiori et al. 2011, arXiv:1012.3428 Resolution: 2.54 AA (fwhm) 0.9 AA sampling ssp_M11_MILES.'imf'z10m4.bhb: 11 ages, 5-15 Gyr 3500.0 - 7429.4 AA 4367 flux points Blue Horizontal Branch ssp_M11_MILES.'imf'z10m4.rhb: 11 ages, 5-15 Gyr 3500.0 - 7429.4 AA 4367 flux points Red Horizontal Branch ssp_M11_MILES.'imf'z0001.bhb: 14 ages, 2-15 Gyr 3500.0 - 7429.4 AA 4367 flux points Blue Horizontal Branch ssp_M11_MILES.'imf'z0001.rhb: 14 ages, 2-15 Gyr 3500.0 - 7429.4 AA 4367 flux points Red Horizontal Branch ssp_M11_MILES.'imf'z001: 34 ages, 55 Myr to 15 Gyr 3500.0 - 7429.4 AA 4367 flux points ssp_M11_MILES_UVextended.'imf'z001: 31 ages, 55 Myr to 15 Gyr 1000.7 - 7429.4 AA 7144 flux points ssp_M11_MILES.'imf'z002: 50 ages, 6.5 Myr to 15 Gyr 3500.0 - 7429.4 AA 4367 flux points ssp_M11_MILES_UVextended.'imf'z002: 47 ages, 6 Myr to 15 Gyr 1000.7 - 7429.4 AA 7144 flux points UV extended (models merged around 3750 AA) ssp_M11_MILES_revisednearIRslope.'imf'z002: 50 ages, 6.5 Myr to 15 Gyr 3500.0 - 7429.4 AA 4367 flux points Revised near-IR slope ssp_M11_MILES_UVextended_revisednearIRslope.'imf'z002: 47 ages, 6.5 Myr to 15 Gyr 1000.7 - 7429.4 AA 7144 flux points UV extended (models merged around 3750 AA) Revised near-IR slope ssp_M11_MILES_UVextended_revisednearIRslope_nearIRextended.ssz002: 10 ages, 3 Gyr to 15 Gyr 1000.7 -199948.9032 AA 73626 flux points UV extended (models merged around 3750 AA) Revised near-IR slope Extended into the near-IR by merging with MARCS-based models ssp_M11_MILES.'imf'z004: 25 ages, 100 Myr to 15 Gyr 3500.0 - 7429.4 AA 4367 flux points ssp_M11_MILES_UVextended.'imf'z004: 22 ages, 100 Myr to 12 Gyr 1000.7 - 7429.4 AA 7144 flux points UV extended (models merged around 3750 AA) -------------------------------------------------------------------------------------------------- ELODIE-BASED MODELS: These models are based on the stellar library ELODIE by Prugniel et al. (2007). * Caveat regarding the flux calibration/de-reddening of the hottest stars, which will affect the youngest ages, < 100 Myr at solar metallicity. * A few cool, high-resolution theoretical stars (Gustafsson et al. 2008) have been added for completeness. * Fairly poor sampling of stellar parameter space at the lowest metallicity affects the reliability of these models. Resolution: 0.55 A (fwhm) 0.2 AA sampling ssp_M11_ELODIE.'imf'z10m4.rhb: 10 ages, 6-15 Gyr 3900.0 - 6800.0 AA 14501 flux points ssp_M11_ELODIE.'imf'z10m4.bhb: 6 ages, 6-11 Gyr 3900.0 - 6800.0 AA 14501 flux points ssp_M11_ELODIE.'imf'z001: 34 ages, 55 Myr to 15 Gyr 3900.0 - 6800.0 AA 14501 flux points ssp_M11_ELODIE.'imf'z002: 57 ages, 3 Myr to 15 Gyr 3900.0 - 6800.0 AA 14501 flux points ssp_M11_ELODIE_UVextended.'imf'z002: 54 ages, 3 Myr to 15 Gyr 1000.2 - 6800.0 AA 29000 flux points UV extended version, models merged around 3950 AA. ssp_M11_ELODIE.'imf'z004: 25 ages, 100 Myr to 15 Gyr 3900.0 - 6800.0 AA 14501 flux points ---------------------------------------------------- DESCRIPTION OF MODELS BASED ON THEORETICAL LIBRARIES ---------------------------------------------------- MARCS-BASED MODELS: These models are based on the theoretical stellar library by Gustafsson et al. 2008. * Temperatures of theoretical stars allow the calculation of only old models, namely 3 Gyr and above * The lower metallicity Z=10^-4 ('z10m4') has [alpha/enhanced]=0.4 atmospheres. * There will be a dedicated follow-up publication focus on these models and more under computation. Resolution: R=20,000 0.065 AA sampling ssp_M11_MARCS.'imf'z002: 13 ages, 3 Gyr to 15 Gyr 1299.5756 - 199948.9032 AA 100724 flux points ssp_M11_MARCS.'imf'z004: 13 ages, 3 Gyr to 15 Gyr 1299.5756 - 199948.9032 AA 100724 flux points ssp_M11_MARCS.'imf'z10m4: 9 ages, 7 Gyr to 15 Gyr 1299.5756 - 199948.9032 AA 100724 flux points