
*************************************************************
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**  THEORETICAL ISOCHRONES WITH AN IMPROVED TP-AGB PHASE   **
**  June 22, 2006                                          **
**  Containing the isochrones used by Cioni et al. 2006ab  **
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The present tarfile (isoc_cgmh06.tar.gz) contains the isochrone files
used in the papers

 Cioni, M.-R. L., Girardi, L., Marigo, P., & Habing, H. J. 2006,
 Astronomy and Astrophysics 448, 77, AGB stars in the Magellanic
 Clouds. II. The rate of star formation across the LMC

 Cioni, M.-R. L., Girardi, L., Marigo, P., & Habing, H. J. 2006,
 Astronomy and Astrophysics 452, 195, AGB stars in the Magellanic
 Clouds. III. The rate of star formation across the Small Magellanic
 Cloud

These isochrones are for 6 different values of initial metallicity,
and are in a format very similar to the one used by:

 "Theoretical isochrones in several photometric systems
 I. Johnson-Cousins-Glass, HST/WFPC2, HST/NICMOS, Washington, and ESO
 Imaging Survey filter sets" by L. Girardi, G. Bertelli, A. Bressan,
 C. Chiosi, M.A.T. Groenewegen, P. Marigo, B. Salasnich, and A. Weiss,
 2002, Astronomy & Astrophysics, 391, 195.

(see also http://pleiadi.pd.astro.it/isoc_photsys.02.html) with two
important additions:

- The column "C/O" gives the surface carbon-to-oxygen number ratio,
which is useful to identify C-type stars (those with C/O>1). For the
pre-TP-AGB evolution, the C/O ratio is set to the solar value in
Girardi et al. 2000 tracks, i.e. 0.479.

- The column "McTPAGB" givs the core mass during the TP-AGB phase, in
solar masses. It is set to 0.0 for all pre-TPAGB stages. This quantity
may be used to identify and to simulate, a posteriori, the pulse cycle
luminosity and Teff variations that occur during the TP-AGB. The
procedure will be detailed in future papers, and is briefly outlined
in

 Marigo, P., Girardi, L., & Chiosi, C. 2003, Astronomy and
 Astrophysics 403, 225, The red tail of carbon stars in the LMC:
 Models meet 2MASS and DENIS observations.

The photometric system is the Johnson-Cousin-Glass UBVRIJHK as
standardized by Bessell and Bessell & Brett, at least for all O-rich
stars (i.e. excluding the brief C-type phase). All details about the
transformation to this system are provided in Girardi et al. (2002).

For C-rich stars, instead, the J and K magnitudes are given by
semi-empirical BC and Teff-colour transformations suitable for
C-stars, as described in the above-mentioned papers (Marigo et
al. 2003, and Cioni et al. 2006ab).

Future releases of "TP-AGB improved" isochrones will include other
photometric systems as well.

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TABLES OF ISOCHRONES
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The following isochrone files are available:

------------------------------------------------------------------
FILENAME			COMPOSITION		REFERENCE*
------------------------------------------------------------------
isoc_cgmh06/isoc_z0004.dat	[Z=0.0004, Y=0.230]	Gi00+Be94
isoc_cgmh06/isoc_z001.dat	[Z=0.001, Y=0.230]	Gi00+Gi01
isoc_cgmh06/isoc_z004.dat	[Z=0.004, Y=0.240]	Gi00+Be94
isoc_cgmh06/isoc_z008.dat	[Z=0.008, Y=0.250]	Gi00+Be94
isoc_cgmh06/isoc_z019.dat	[Z=0.019, Y=0.273]	Gi00+Be94
isoc_cgmh06/isoc_z030.dat	[Z=0.030, Y=0.300]	Gi00
------------------------------------------------------------------
*Note: the REFERENCE column refers only to the pre-TP-AGB tracks. 
The TP-AGB tracks are described in Marigo et al. (2003), and in
Cioni et al. (2006ab).

Users are _strongly_ encouraged to refer to the original papers,
listed in the last column above, for information about the pre-TP-AGB
phases, and about massive stars.

Each file contains a complete series of isochrones with log(age/yr)
values at equally spaced intervals of Delta(log age)=0.05 (i.e., two
consecutive isochrones differ by just 12 percent in their ages.)

Each one of these files contains
HEADER LINE: with the exact age and metallicity value of 
	the isochrone;
followed by 117 columns with:
Column (1)  log(age/yr) --> logarithm of the age (in yr);
Column (2)  M_ini --> initial mass of the star (in solar units);
Column (3)  M_act --> actual mass of the star, i.e., the mass 
	obtained considering the previous history of mass-loss;
Column (4)  logL/Lo --> logarithm of surface luminosity (in solar 
	units), log(L/Lsun);
Column (5)  logTef --> logarithm of effective temperature (in K), 
	log(Teff/K);
Column (6)  logG --> logarithm of surface gravity (in cgs units);
Column (7)  Mbol --> absolute bolometric magnitude;
Columns (8) to (15)  --> absolute magnitude in UBVRIJHGK pass-bands;
Column (16) C/O --> surface carbon-to-oxygen number ratio;
Column (17) McTPAGB --> core mass during the TP-AGB phase, in Msun.

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REFERENCES
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(A more complete list can be found in the A&A papers mentioned above.)

Bertelli G., Bressan A., Chiosi C., Fagotto F., Nasi E., 1994, 
	 A&AS 106, 275 (Be94)
Girardi L., Bressan A., Bertelli G., Chiosi C., 2000, A&AS 141, 371 
	(Gi00)
Girardi L., 2001, unpublished tracks (Gi01)
Kroupa P., 2001, MNRAS 322, 231
Marigo P., Girardi L., 2001, A&A 377, 132 (MG01)

