Introduction to GALSYNTH

 a WEB interface for GRASIL

by Lorenzo Paoletti, Amedeo Petrella and Danilo Selvestrel


GALSYNTH is a WEB based interface for the model GRASIL and the ancillary code CHE_EVO. The purposes are:

  1. Guide to a correct and easy use; 

  2. Allow to use the codes without downloading and installing on your computer;

  3. Provide computing power;

The use of the interface is relatively self-explanatory, once you have astrophysical knowledge of the model. It allows the user to access a substantial portion of the flexibility of GRASIL, though not all. Examples of possibilities that are since long implemented in GRASIL but still not accessible through GALSYNTH includes the freedom to specify the dust mixture and the inclusion of a population of molecular clouds with different mass and size. If you believe that these features are vital for your work, by now you can only use GRASIL directly. 

For convenience we list here the steps required to obtain GRASIL models with GALSYNTH.

The first time you need to register, inserting your name and a valid email address, where you will immediately receive a password.

Then you can login to the system. You will see on the left column two clickable words: SETs and Jobs. The former are sets of input parameters for the codes (CHE sets for CHE_EVO or PAR sets for GRASIL), including definitions of possible iterations on parameters (still unsupported for CHE_EVO paramaters). SETs can be edited, saved, modified, reused. Jobs are batch executions of CHE_EVO+GRASIL sequence according to selected SETs. They will be executed on a pool of computers, and the user will be notified once the Jobs are completed, if requested.

Then you first define and edit your own CHE and PAR SETs (click on SETs-insert), assigning them convenient names. You can choose among three different level of use: basic, extended and advanced. The higher the level, the more parameter can be edited and with greater allowed range. In the SETs edit window, you will see, for each parameter, appropriate fields for its value and, if the parameter is iterable, for optional step and number of loops. On the left, a short explanation text for the meaning of that parameter and the allowed range, which sometimes may change with the level. On the right, a "?". Clicking on that, a popup window will show more explanatory text on the parameter.

When you have defined at least one CHE and PAR SETs, you can start your first Job (click on Jobs-insert). Before clicking the "create" button, select from the menu one of your SETs for each code. After the Job is created, the first computer in the pool which is free will execute it.

You can follow the status of your Jobs clicking "Jobs-search", and once is finished, you can download the output.

For more explanations, have a look to the PDF of a presentation containing some screenshots produced by GALSYNTH.

If you use GALSYNTH to produce scientific work, we kindly ask you to reference (at least) the original GRASIL paper Silva, L., Granato, G.L., Bressan, A., Danese, L., 1998, ApJ, 509, 103 and give appropriate aknowledgement to INAF-OAPD.