Source Finding¶

Current in flint the aegeantools package is the only source finder supported. Even so, it is only used through a container as a CLI callable and not directly accessed via its private API.

There are two reasons where aegeantools is currently used:

1 - background and noise maps 2 - slim source finding

Background and noise estimation¶

There are weak links to the BANE program packaged in aegeantools. The computation of the bkg and rms maps through a rolling sigma-clipping boxcar function produces reliable and easily accessible direction-dependent diagnostics. In early versions of flint these were used as the basis of our clean mask creation routines. The rms map is also used when creating a summary field figure.

We note that in the latest version of aegeantools that there is an ongoing bug that can lead to a deadlock issue. For these reason we only expose the cores argument and have logic to ensure that the stripes BANE parameters it always one less than this.

class BANEOptions(BaseOptions):
    """Container for basic BANE related options. Only a subclass of BANE options are supported."""

    grid_size: tuple[int, int] | None = (16, 16)
    """The step interval of each box, in pixels"""
    box_size: tuple[int, int] | None = (196, 196)
    """The size of the box in pixels"""
    cores: int = 12
    """Number of cores to use. The number of stripes will be less than this number."""

Source finding¶

Flint offers the aegean source finding tool to be executed after BANE has been invoked. These two tools will always run sequentially. A limited set of aegean options have been exposed.

Importantly the intention here is to obtain a set of diagnostic results with minimal computation. The AegeanOptions exposed correspond to equivalent aegean CLI arguments. Do not that the default value of noconv is True – this mode does not handle the correlation of adjacent pixels.

class AegeanOptions(BaseOptions):
    """Container for basic aegean options. Only a subclass of aegean options are supported.

    Of note is the lack of a tables option (corresponding to --tables). This is dependent on knowing the base output name
    and relying on aegean to also append a suffix of sorts to the outputs. For that reason
    the aegean command generated will always create the table option.
    """

    nocov: bool = True
    """Whether aegean should attempt to model the co-variance of pixels. If true aegean does not. """
    maxsummits: int = 4
    """The maximum number of components an island is allowed to have before it is ignored. """
    autoload: bool = True
    """Attempt to load precomputed background and rms maps. """

Caution

The flint_aegean CLI will append options from both BANEOptions and AegeanOptions, and craft instances of these objects automatically. The default type of nocon and autoload will be translated to store_false options in argparse.ArgumentParser. If you want to use the quick version of aegean do not pass --noconv to the flint_aegean find CLI call.

Accessing via the CLI¶

The primary entry point for the source finding with aegean in flint is via flint_aegean:

A basic interface into aegean source finding routines.

usage: flint_aegean [-h] {find} ...

Positional Arguments¶

mode: Possible choices: find

Sub-commands¶

find¶

Run BANE with default options.

flint_aegean find [-h] [--grid-size GRID_SIZE GRID_SIZE]
                  [--box-size BOX_SIZE BOX_SIZE] [--cores CORES] [--nocov]
                  [--maxsummits MAXSUMMITS] [--autoload]
                  image container

Positional Arguments¶

image: The image that BANE will process
container: Path to container with AegeanTools

Inputs for BANEOptions¶

--grid-size

The step interval of each box, in pixels

Default: (16, 16)

--box-size

The size of the box in pixels

Default: (196, 196)

--cores

Number of cores to use. The number of stripes will be less than this number.

Default: 12

Inputs for AegeanOptions¶

--nocov

Whether aegean should attempt to model the co-variance of pixels. If true aegean does not.

Default: True

--maxsummits

The maximum number of components an island is allowed to have before it is ignored.

Default: 4

--autoload

Attempt to load precomputed background and rms maps.

Default: True