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SINOPSIS

SINOPSIS stands for SImulatiNg OPtical Spectra wIth Stellar population models. It is a spectrophotometric fitting code written in Fortran 90 (yes, yes, I know...) 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 in 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.

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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 implementation that allows the automatic analysis of IFU data is described in Fritz et al. 2017.

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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 (August, 2024) a very well tested tool, as it was used to fit and interpret the spectra of a variety of galaxies and different type of data, including integral field one. 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.

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An example of a spectral model obtained with SINOPSIS. The green line and red points represent the integrated MUSE spectrum and the JWST photometry, respectively. The red line is the spectral model. Blue points are the model photometric points calculated from the model spectrum. The figure is taken from Vulcani et al. 2023.

What's NEW in SINOPSIS

Version 1.8.0 is now available. It includes:

  1. Minor bugs/exceptions fixes

  2. Redefinition of continuum bands for the observed constraints

  3. Inclusion of the FSPS models by Conroy & Gunn 2010 (gas emission already calculated for this models)

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