========== User Guide ========== ----------- Get Started ----------- This is a simple guide on how to use the **fg21sim** package to carry out the foregrounds simulation, which produces the all-sky maps or sky patches of the enabled foreground components. The simulation of the following foreground components requires specific template map(s) and/or observational/simulation catalog(s) as the input: * ``galactic/synchrotron``: requires the Haslam 408 MHz survey as the template map, and the spectral index map. * ``galactic/freefree``: requires the Hα map and the dust map. * ``galactic/snr``: requires the catalog of the Galactic SNRs. See the `template data `_ page for more details on the input data and how to obtain them. Then, a configuration file is required to run the foregrounds simulation, which controls all aspects of the simulation behaviors. There are two types of configuration options: *required* (which require the user to explicitly provide the values) and *optional* (which already have sensible defaults, however, the user can also override them). Please refer to the `configuration specification file `_ for more information on the available options. Also there is a brief `test configuration file `_ which may be useful to test whether this package is correctly installed and runs smoothly. Finally, the foregrounds simulation can be kicked off by executing:: $ fg21sim --logfile fg21sim.log fg21sim.conf The program will read configurations from file ``fg21sim.conf``, and log messages to both the screen and file ``fg21sim.log``. --------- Sky Patch --------- When doing high-resolution simulations, it is more appropriate to specify a sky patch (e.g., 10x10 deg^2) instead of using the whole sky. For simulating Galactic diffuse emission maps, the template sky patches are required as the input. To generate such sky patches, use the ``get-healpix-patch`` tool to extract the needed patch from the all-sky HEALPix template maps. ------------- Point Sources ------------- The sky maps of extragalactic point sources can be simulated using these `pointsource tools`_ that were developed for use in `Wang et al. 2010`_. ---------------------- Observation Simulation ---------------------- In order to incorporate the instrumental effects into the simulated sky maps, the latest `SKA1-Low layout configuration`_ (released on 2016 May 21) is employed to carry out the observation simulation. The `OSKAR`_ simulator is used to perform the interferometric observations. The ``make-ska1low-model`` tool was writen to generate the *sky model* of the SKA1-Low for use by ``OSKAR``. The simulated *visibility data* are then imaged by utilizing the `WSClean`_ to generate the "observed" images. The scripts that help carry out the observation simulations can be found at `atoolbox/astro/oskar`_. .. _`pointsource tools`: https://github.com/liweitianux/radio-fg-simu-tools/tree/master/pointsource .. _`Wang et al. 2010`_: http://adsabs.harvard.edu/abs/2010ApJ...723..620W .. _`SKA1-Low layout configuration`: https://astronomers.skatelescope.org/wp-content/uploads/2016/09/SKA-TEL-SKO-0000422_02_SKA1_LowConfigurationCoordinates-1.pdf .. _`OSKAR`_: https://github.com/OxfordSKA/OSKAR .. _`WSClean`_: https://sourceforge.net/projects/wsclean/ .. _`atoolbox/astro/oskar`: https://github.com/liweitianux/atoolbox/tree/master/astro/oskar