SINOPSIS is a spectrophotometric fitting code which aims at reproducing the combined spectral and broad-band photometric data of galaxies. It combines the theoretical spectra of Simple Stellar Population models (SSP) with templates of the near, mid, and far infrared (NIR, MIR, FIR) emission (DISCLAMER: the FIR option is still under developing).

The roots of the code can be found the paper by Poggianti, Bressan & Franceschini, 2001. The code has evolved since then, becoming more powerful, versatile and fast, but the idea is pretty much the same.

SINOPSIS is currently one of the few spectral fitting codes available in the literature which does not assume any pre-determined star formation history and that uses no pre-computed libraries. Furthermore, it adopts a treatment of extinction that can be, in principle, fully dependent on the stellar age (i.e. the “selective extinction” hypothesis: younger stars tend to be more affected by dust extinction with respect to the more evolved ones).

Another advantage of SINOPSIS is that it uses a very robust method to calculate the equivalent width of spectral lines, even in low S/N spectra, that are used as constraints to derive the star formation history of a galaxy. This method is described in detail in Fritz et al. 2011 and Fritz et al. 2014, and we are currently working on it to make it even more robust and reliable.

The basis of this model rely on the spectral fitting code that was used to reproduce and analyze WINGS optical spectra. Here you can find a couple of examples of fits and Star Formation History reconstructions.

SINOPSIS is currently (July, 2018) a very well tested tool, as it was used to fit and interpret the spectra of more than 104 galaxies, including integral field data. Nevertheless, some of the options are still on a test phase (e.g. the far-infrared emission part). As long as you want to use it to reproduce a set of optical spectra (or even only 1), you should be able to do it right away, after downloading and compiling it.

To have a quick look on SINOPSIS’ installation, usage, options, and possibilities, you can download its  (incomplete, for the moment) USER MANUAL.

The source code, together with all the needed models and files, can be instead downloaded from GitHub upon request (drop me an email!). A python script will very soon be available to visualize the results of the fit. An example of the set up file (config.sin) is also given, together with examples of input catalogs in various format.

Version 1.6.8 is available. Big thanks to Dani Díaz for implementing an installation script that should make things much easier and automatic.

Among the new features (with respect to version 1.6.4, the latest here described):

  1. 1.    Most of the default input file are now more consistently “customizable”, and in case they will have to be located in the directory where sinopsis is run (cosmology, continuum band definition, stellar population parameters definition);

  2. 2.    The spectral normalization wavelength is now customizable;

  3. 3.    It is now possible to choose the age of the oldest SSP in a consistent way with the adopted cosmology;

  4. 4.    Equivalent widths are now measurable at fixed, custom-defined passbands,as well;

  5. 5.   Added the possibility, when fitting a whole data cube, to use a mask indicating where the fit has to be performed. The mask needs to be in fits file.

  6. 6.  It is now possible to give and use as constraints the equivalent widths of lines outside the observed spectral range (useful if you get the information from somewhere else).

  7. 7.   Extinction values for all the SSPs, when using the non-parametric SFH prescription, are now written in the output file.

  8. 8.   The definition of the final age bins is now made according the the SSP set used.

  9. 9.   These and many more!!

Unfortunately, the new SSP set (Charlot & Bruzual, 2021, in prep.) is not available yet. It will be as soon as I got the permission from Gustavo Bruzual. These will be hopefully incorporated from version 1.7.0, together with several other improvements (gas emission treatment, equivalent width measurements, output options, and many more).

Feel free to send me an email if you want to know more about the code.

SINOPSIS can now read spectra in .fits format. This includes single spectra (one file-one spectrum), 2D fits tables (on spectrum per row, as in the case of the AAOMEGA instrument on the Australian Astronomical Observatory telescope), and spectra collected by IFU, such as MUSE on the VLT. This latter option, in particular, has been deeply tested on the spectra of the GASP project, a VLT large program to study Jellyfish galaxies.

The code has also been optimized: it takes less than 1 second to fit a MUSE spectrum on a 3.5 GHz Intel CPU machine. This makes it feasible to fit an entire MUSE cube (more than 1.3e5 spectra) in realistic timescales.

One of my students, Adan Artola, has started to work on the improvement of the equivalent width measurement method used by SINOPSIS, as part of his Master Thesis.

Big news are about to come!

SINOPSIS is also available through