21 August 2015 (Current release)

Source code and Mac-OS binaries

This release reflects the changes made for Bell, Mamajek & Naylor.

1) The grid now needs membership probabilities for all the stars. These can be given by having a colour labelled "Prior" in the input file, which allows you to have different probabilities for each star. If such a column is not present then grid will prompt for a value to apply to all stars. For details of how to use this feature see Section 4.1 and Appendix C of Bell, Mamajek & Naylor.
2) The output catalogues grid writes now have the prior probability used written in, but also the calculated probability of membership from the stars CMD position, called "Post" (short for posterior probability).
3) The programme to calculate Pr(tau^2), called tau^2 has been completely re-written with a new algorithm, though the prompts remain the same. The old version is still available as old_tau2.
4) Some of the file names have changed, which I hope makes them more logical (see manual).
5) There is a program to create the cluster format input file from a simple ascii file, called ascii2cluster.
6) The mass function used by monte is now that of Dabringhausen J., Hilker M., Kroupa P., 2008, MNRAS, 386, 864 (it was a Salpeter function).

16 October 2014

Source code and Mac-OS binaries

This release is primarily to update the available isochrones to include those from Bell et al (2014), and update Example 2 to use them rather than the older Jeffries Pleiades tuning.

1) Many of the sub-routines have been re-grouped.
2) A bug which made it impossible to use user isochrones in monte cured.
3) A bug whereby all the singe stars were written out twice in the ascii file which gives the first 10,000 stars from monte cured.
4) The Bolometric luminosity of the Sun now picked up from the BC file headers (if its there) and set to Eric Mamajek's value.

28 January 2014

Source code and Mac-OS binaries

For this release large parts of the code which create the isochrones have been re-written, which has resulted in a simpler structure, within which it is easy to add new models. As a result there is a far richer range of options available, yet the code is lightly shorter than the previous release. Old hands, used to previous versions should note the following points.

1) The absolute values of tau^2 have changed. Of course this does not make any practical difference as only relative values used, but there was a conceptual "bug" in which when normalising the isochrone image I did not divide by the pixel size.
2) Monte is structured so that the binary fraction can be a function of primary mass. Now the binary fraction for stars greater than 14.4Mo is 1.5 times the normal binary fraction, and the mass ratio for such stars is distributed as described in Naylor (2009; IAU paper).
3) The extinction vector for the Tycho colours has been improved. The difference between the new values and those in Mayne & Naylor (2008) is small (delta Av = 0.05*E(B-V)) so does not affect the results in Mayne & Naylor or Naylor (2009), but would change things if you had large extinctions.
4) Some more FITS keywords have been added to the output of monte so that both DS9 and the latest version of GAIA give you the co-ordinates in colour-magnitude space.
5) The scripts have been updated and uncer changed slightly to make the code compile on 64-bit machines.

21 August 2009



Bug found by Phill Cargile fixed, which caused a crash on certain Bessell atmospheres.

27 June 2009



(1) This release is of the version of the software used in Naylor (2009).
(2) The major change is that the age axis is now given in log10(yrs) rather than Myr. This makes things much easier when dealing with data which have a large uncertainty in age, as this is a far more natural axis to use. It also means the prior probability is flat in logarithmic not linear space, which makes a difference if the uncertainties are more than half a dex.
(3) There are now "user" isochrones, which allow you to supply a file of either (i) luminosity, effective temperature and gravity or (ii) colour and magnitude for a given age. Now interpolation in age is carried out on this files, allowing you to make the choice as to how this interpolation is done is therefore yours. The formats are dealt with in the section of the manual on isochrones.

29 October 2008


Documentation fix for example 2.

15 October 2008


To be on the safe side, I switched off the extrapolation of the colour-Teff relationships.

24 September 2008

This was a major update in techniques, which were presented in Naylor (2009).

(1) I use a new normalisation, which retains the mass function in the grids, but then normalises the grid to sum to one between the brightest and faintest datapoints. This avoids the problem of the normalisation going infinite if the isochrone is vertical.
(2) To generate the uncertainties I now use the uncer method (replacing bootstrap), for which there is a brief description. Its faster and more accurate.
(3) The calculation of the expected value of tau^2 has been improved, and is now done in a program called tau2, which replaces tau. The old estimate became increasingly poor as the number of free parameters increased.

19 February 2008

(1) A correction to Example 2. The extra uncertainty to be added to the colour was given as 0.03, it should be 0.042. Both the web-page and the sample files have been updated to reflect this change.

21 August 2007

(1) V vs V-I for the Geneva isochrones.
(2) V vs B-V for the Siess and Baraffe isochrones.
(3) The option to use Bessell et al (1998) colour and bolometric corrections.
(4) Grid now imposes the upper limit on tau-squared to be the tau-squared of the best fitting data point (i.e. that with the lowest tau-squared) plus some value. We do this so that if a different normalisation for tau-squared is used, which effectively adds a constant to all the tau-squared values, the answer remains the same. With the chi-squared-like normalisation the lowest tau-squared value was so close to zero this has little effect on the fits.

05 June 2007

(1) The Padova option was using the z=0.004 tracks from the Cioni et al (2006) papers, not as stated on the web pages Girardi et al (2002). The code has been changed so the web page is correct, and the web page now explicitly states its the z=0.019 models.

03 October 2006

(1) Corrected a problem whereby if the mass-range you requested outran that available in the isochrones for model numbers greater than 20 (i.e. those which come ready calibrated in colour and magnitude), you got some strange low-level effects in the 2D isochrones.
(2) Updated Example 1 so the numbers are correct for the new code (the differences are within the uncertainties).
(3) Added .in files to Example 1, which contain the precise inputs needed to run the programs.

30 September 2006

(1) Corrected bundle so it includes files which are soft links on my machine.
(2) Compiled all software statically, to improve portability.