Worthey Model Interpolation Engine - Padova94-based

This form allows one to create arbitrary mixtures of single-burst populations based upon an alternate stellar evolutionary isochrone library (Bertelli et al. 1994, A&AS, 97, 851). The models are still those of Worthey 1994, ApJS, 95, 107. Keep ages between 0.0039 and 19.9 Gyr, and [Fe/H] between -1.7 and +0.4. Lick/IDS spectral indices will be output only if no age is younger than 0.4 Gyr = 400 Myr. The relative (mass) weights you give will be normalized so that the total initial population mass comes out to a million solar masses. In the box, enter (Age in Gyr, [Fe/H], relative weight) trios separated by white space. E.g., typing 12.0 0.0 97 (return) 0.5 0.1 3 (return) will show you what an old, solar metallicity population looks like when "polluted" by 3% (by mass) of a younger population 500 Myr old but 0.1 dex more metal-rich.

Disclaimer: Some aspects of these models are clearly wrong, like RGB/AGB tip temperatures and horizontal branch behavior, so the user is advised that the results obtained from this page are "substandard" compared to models actually published in the literature. This page is meant to be helpful but not authoritative.

Output options:
Show colors, magnitudes, spectral indices, SBF magnitudes
Send a file with all of that plus an SED.

Model flavor:
Default models: Salpeter (2.35) IMF.

Note: although there are choices for IMF exponent, the Padova isochrones do not include stars below 0.6 solar masses, so for old populations the very stars that cause spectral changes as the IMF changes are missing. For young populations the 0.6 Mo cutoff becomes less important.

IMF exponent up 0.5 (2.85)
IMF exponent up 1.0 (3.35)
IMF exponent down 0.5 (1.85)
IMF exponent down 1.0 (1.35)

You might find the fine print helpful.

If you want this on your own computer, dowload: pad-lib-fits.tar.gz (FITS files containing the various vanilla models), and fortran.tar.gz (interpolation programs, not including the FITSIO routines). And here are the alternate power-law IMF slope FITS directories. The gzipped files are 14 MB, and they expand into about 35 MB each. Po_Salp-1.0.tar.gz - Po_Salp-0.5.tar.gz - Po_Salp+0.5.tar.gz - Po_Salp+1.0.tar.gz . I don't want these to propagate uncontrollably, so please send me an email if you download the files. Thanks.

Go to:
Claus Leitherer's collection of population synthesis links.
Guy Worthey page.
© 1996-2016. Guy Worthey.

Last modified: Thu Apr 20 11:43:11 CDT 2000