SINOPSIS

 
 

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 test phase).


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 (March, 2017) a very well tested tool, as it was used to fit and interpret the spectra of more than 104 galaxies. 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 (see below).

The source code, together with all the needed models and files, can be instead downloaded here. 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.

SIMULATING OPTICAL SPECTRA WITH STELLAR POPULATION MODELS

Version 1.6.3 is about to be released. I have skipped the public release of version 1.6.2 as this was used to optimize the code for MUSE-like data while keeping, in the meantime, stability when used with other kind of data. Lots of minor bugs have also been corrected. Big thanks to Edoardo Iani, master student at Padova Physics & Astronomy department, for his patience. With his help SINOPSIS now successfully compiles on Ubuntu as well.

Among the new features (with respect to version 1.6.1):

  1. 1.    Improved stability, with a focus on the use of photometry in combination with spectra;

  2. 2.    More output information when datacube are used;

  3. 3.    Possibility for the user to define their own set of continuum bands to be reproduced;

  4. 4.    You can now use different redshifts for the stellar and for the gas component;

  5. 5.    Use of SSPs which are consistent with the age of the Universe at any given redshift.

  6. 6.    The “advanced catalog” option is back. Now you can tweak measurements on a (presumably small) set of spectra, to even better customize the constraints.


Unfortunately, the new SSP set (Charlot & Bruzual, 2017) is not available yet. It will be as soon as I got the permission from Gustavo Bruzual.


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 www.sedfitting.org.

NEW!

SINOPSIS User Manual

Download SINOPSIS