The models available in this section are not included in the distribution of ULySS. They can be downloaded here, and stored as local files (the directory models/ would be an appropriate location).
The following stellar population models grids are intended to be used with ULY_SSP. All the models have the same intensity unit: 10^-7L_☉/M_☉/Å (where L_☉=3.826×10³³ erg/s and M_☉=1.989×10³³ g). If the units of the spectrum to analyse is 10^-17 erg/s/cm²/Å (like the SDSS), the weight determined during the fitting process will be in : 0.261×10^-43 M_☉ / cm², and the mass = 0.3127×10⁷ weight D² M_☉, where D is the distance in Mpc, assuming there is no extinction.

Model file	Code	Library	IMF(1)	SFH(2)	λλ / Resolution	Notes
PHR_SB_e31_Salp.fits	PegaseHR	Elodie.3.1	Salpeter Mass: 0.1 to 120 M☉ Slope: -1.35	SSP	3900-6800Å R = 10000	Isochrones: Padova 1994 Age range: 1 to 20000 Myr Metallicity range: -2.3 to +0.69 dex.
PHR_SB_e31_Krou.fits	PegaseHR	Elodie.3.1	Kroupa Mass: 0.1 to 0.5 M☉ Slope: -0.3 Mass: 0.5 to 1 M☉ Slope: -1.2 Mass: 1 to 120 M☉ Slope: -1.7	SSP	3900-6800Å R = 10000	Isochrones: Padova 1994 Age range: 1 to 20000 Myr Metallicity range: -2.3 to +0.69 dex.
PHR_SB_e31_Toph.fits	PegaseHR	Elodie.3.1	Topheavy Mass: 0.1 to 120 M☉ Slope: -0.8	SSP	3900-6800Å R = 10000	Isochrones: Padova 1994 Age range: 1 to 20000 Myr Metallicity range: -2.3 to +0.69 dex.
PHR_Const_e31_Salp.fits	PegaseHR	Elodie.3.1	Salpeter Mass: 0.1 to 120 M☉ Slope: -1.35	cst	3900-6800Å R = 10000	Isochrones: Padova 1994 Age range: 1 to 20000 Myr Metallicity range: -2.3 to +0.69 dex.
PHR_SB_lcb_Salp.fits	PegaseHR	LCB	Salpeter Mass: 0.1 to 120 M☉ Slope: -1.35	SSP	100-20000Å (low resolution)	Isochrones: Padova 1994 Age range: 1 to 20000 Myr Metallicity range: -2.3 to +0.69 dex.
PHR_SB_lcb_Krou.fits	PegaseHR	LCB	Kroupa Mass: 0.1 to 0.5 M☉ Slope: -0.3 Mass: 0.5 to 1 M☉ Slope: -1.2 Mass: 1 to 120 M☉ Slope: -1.7	SSP	100-20000Å (low resolution)	Isochrones: Padova 1994 Age range: 1 to 20000 Myr Metallicity range: -2.3 to +0.69 dex.
PHR_SB_lcb_Toph.fits	PegaseHR	LCB	Top heavy Mass: 0.1 to 120 M☉ Slope: -0.8	SSP	100-20000Å (low resolution)	Isochrones: Padova 1994 Age range: 1 to 20000 Myr Metallicity range: -2.3 to +0.69 dex.
PHR_Const_lcb_Salp.fits	PegaseHR	LCB	Salpeter Mass: 0.1 to 120 M☉ Slope: -1.35	cst	100-20000Å (low resolution)	Isochrones: Padova 1994 Age range: 1 to 20000 Myr Metallicity range: -2.3 to +0.69 dex.
Vaz_SB_mil_un13.fits.gz	Vazdekis v9.0	Miles	Salpeter Mass: 0.1 to 100 M☉ Slope: -1.35	SSP	3540.5-7409.6Å R = 2000	Isochrones: Padova 2000 (Gerardi et al 2000) Age range: 63 to 17780 Myr Metallicity range: -2.3 to +0.2 dex.
Vaz_SB_mil_kb13.fits.gz	Vazdekis v9.0	Miles	Kroupa 2001 binaries corrected Mass: 0.1 to 0.5 M☉ Slope: -0.3 Mass: 0.5 to 100 M☉ Slope: -1.3	SSP	3540.5-7409.6Å R = 2000	Isochrones: Padova 2000 (Gerardi et al 2000) Age range: 63 to 17780 Myr Metallicity range: -2.3 to +0.2 dex.
GAL_SB_ste_Chab.fits	GalexEv	SteLib	Chabrier Mass: 0.1 to 1 M☉ Slope: exp[-(log m - log 0.08 M☉ )2 / 0.9522 ] Mass: 1 to 100 M☉ Slope: -1.35	SSP	3200-9500Å R = 2000	Isochrones: Padova 1994 (Bertelli et al. 1994). The metallicity range is [-2.3, 0.4] dex.
SB99_Padova_Salpeter.fits	Starburst99	Martins	Salpeter Mass: 0.1 to 120 M☉ Slope: -1.35	SSP	3000-6997Å R = 10000	The isochrones are Padova. Metallicity range: -1.0 to 0.3 dex
SB99_Geneva_Salpeter.fits	Starburst99	Martins	Salpeter Mass: 0.1 to 120 M☉ Slope: -1.35	SSP	3000-6997Å R = 10000	The isochrones are Geneva.
GD05_Geneva.fits	sed@	Martins	Salpeter Mass: 0.1 to 120 M☉ Slope: -1.35	SSP	3000-7000Å R = 10000	The isochrones are Geneva.

Notes:
(1) The initial mass function, IMF, is described by a set of power-law segments in some mass ranges. In the simplest case, like the Salpeter's IMF, it is a single power-law between two limiting mases. The Kroupa's IMF has three slopes.
In the table above, we indicate the mass ranges and the slope in each range.
The IMF is the distribution function of the formed stars as the function of their mass, it is parameterized as: dn/dlog(m) ∝ m^α, or equivalently dn/dm ∝ m^α-1. For Salpter IMF α=-1.35

(2) SFH (star formation history), describe the time dependency of the star formation rate. SSP (single stellar population), is an instantaneous burst of star formation. cst is a constant star formation rate. The 'age' is the time since the star formation started and that the mass of stars which has been formed is proportional to the time, to reach one M_☉ after 20 Gyr.

References for the above table
PegaseHR	Le Borgne et al., 2004
Vazdekis	Vazdekis et al., 2010
GalexEv	BC03, Bruzual and Charlot 2003
Starburst99	Leitherer et al., 1999
sed@	Gonzalez Delgado et al., 2005
Elodie.3.1	Prugniel et al., 2007, Prugniel and Soubiran 2001
LCB	Lejeune et al., 1997, 1998
Miles	Sanchez-Blazquez et al., 2006
CaII	Cenarro et al., 2001
SteLib	Le Borgne et al., 2003
Martins	Martins et al., (2005)

The ULySS distribution contains a TGM model based on the ELODIE library. Other models were prepared by fitting an interpolator over other libraries:

Model file	Library	λλ / Resolution	Source	Notes
miles_tgm.fits alternatively from Vizier	MILES	3536-7410Å R = 2000	Prugniel, Ph., Vauglin, I., Koleva, M., 2011, A&A, 531, A165	First version
miles_tgm2.fits	MILES	3536-7410Å R = 2000	Sharma, K., Prugniel, Ph., Singh, H.P.	Improved version, requires ULySS v1.3 or higher

In addition to the above public models, we are providing here preliminary versions of some more models.

The first SSP models with alpha enhancements build with PEGASE.HR and the ELODIE, CFLIB and MILES libraries, are presented in Prugniel and Koleva, 2011, IAUS 284.

These models are not yet described in details, and they need additional testing... We encourage you to contact us (we may also give fresher versions, or other models). The corresponding SSP components are below (all are not yet posted and will be added in the coming weeks. We will update them).

• PEGASE.HR models with MILES and the polynomial interpolator; Salpeter IMF; natural abundance pattern (Solar neighborhood) PHR_SB_miles_Salp.fits (released 2011/11/18)
• PEGASE.HR models with ELODIE 3.2; Salpeter IMF; resolved in [alpha/Fe] PHR_SB_e32_Salp_alpha.fits (released 2011/12/04)