Catalogs and Sky Map

Catalogs

New in version 0.2.

LWA astronomical source catalogs.

class lsl.catalog.C3C_Catalog

Specific definition for Cambridge 3C source catalogue data file.

parse_file()

Read a source catalog data file.

class lsl.catalog.C4C_Catalog

Specific definition for Cambridge 4C source catalogue data file.

parse_file()

Read a source catalog data file.

class lsl.catalog.Catalog(name)

Class representing astronomical source catalog information. This is an abstract class; derived classes must provide a parse_file() method which populates the catalog object with information from file or other source.

Catalog instances support the read-only collections.Mapping interface. That is, they support the read-only methods of the dict built-in type.

static get_directory()

Returns the path to the catalog data file directory.

lookup(name)

Lookup a source in the catalog.

Param: name - The primary name or alias of the source.

Returns: An object of type CatalogEntry giving the source information,

or None if the name is not found in the catalog.

parse_file()

Read catalog information from file into internal data structures.

class lsl.catalog.CatalogEntry(name, position)

Represents one source entry in a catalogue.

Contains members:

• name - The source name.
• position - The source equatorial J2000 position as object of type transform.CelestialPosition.
• alias_list - A list of strings providing alternate names for the source.

class lsl.catalog.CatalogFactory

Get catalog objects by name. Caches the catalog data so that the data file is parsed only once per session.

classmethod get_catalog(klass, name)

Returns a Catalog object representing the catalog given by name.

classmethod get_names(klass)

Return a list of known catalog names.

class lsl.catalog.F1FGL_Catalog

Specific definition for Fermi LAT first point source catalog.

parse_file()

Read a source catalogue data file.

class lsl.catalog.LWA_Catalog

Specific definition for LWA observation source catalogue data file.

parse_file()

Read a source catalog data file.

class lsl.catalog.PKS90_Catalog

Specific definition for PKS90 source catalogue data file.

parse_file()

Read a source catalog data file.

class lsl.catalog.PKS_Catalog

Specific definition for PKS source catalog.

parse_file()

Read a source catalog data file.

class lsl.catalog.PSR_Catalog

Specific definition for ATNF Pulsar (PSRCAT) catalog. Data file is psrcat.db which can be retreived from: <http://www.atnf.csiro.au/research/pulsar/psrcat/download.html>

parse_file()

Read a source catalog data file.

Sky Map

New in version 0.2.

Classes and methods to model sky brightness and visibility.

class lsl.skymap.ProjectedSkyMap(skyMapObject, lat, lon, utc_jd)

The class for handling the model sky brightness maps over a particular site. This code is the base class for the sky map visible at a specific location. It takes as input a skymap file name and frequency to which the skymap corresponds. It inherits from class SkyMap. It has the following methods:

1. _init_ - takes the array coordinate filename as an input argument.
2. ComputeDirectionCosines - Computes the direction cosines

3. ComputeTotalPowerFromVisibleSky - Sums the power for all visible sources in the sky.

ComputeDirectionCosines()

Compute the direction cosines and return the tuple of arrays (l,m,n).

ComputeTotalPowerFromVisibleSky()

Compute and return the the total power from visible portion of the sky.

class lsl.skymap.SkyMap(skyMapFileName=None, freqMHz=73.9)

The class for handling the model sky brightness maps. This code is the base class for the sky map. It takes as input a skymap file name and frequency to which the skymap corresponds. It has the following methods:

1. _init_ - takes the array coordinate filename as an input argument.

2. NormalizePower - Converts the skymap powers (in Kelvin radiated into 4 pi ster) into a power seen at the antenna. 3. ComputeTotalPowerFromSky - Sums the power for all sources in the sky 4. ScaleSourcePowerstoFrequency - Scales the skymap from the base 73.8 MHz to the desired frequency.

ComputeTotalPowerFromSky()

Compute and return the the total power from the sky.

NormalizePower()

Compute the skymap power (total power radiated into 4 pi steradians) into a power at antenna, based on pixel count.

exception lsl.skymap.SkyMapError

Base class for SkyMap exceptions.

class lsl.skymap.SkyMapGSM(skyMapFileName=None, freqMHz=73.9)

Extension of the SkyMap class to use a Global Sky Model-based set of maps of T0 @ f0, alpha, and beta, where:

For more information on the Global Sky Model, see: http://space.mit.edu/~angelica/gsm/index.html

ComputeTotalPowerFromSky()

Compute and return the the total power from the sky.

NormalizePower()

Compute the skymap power (total power radiated into 4 pi steradians) into a power at antenna, based on pixel count.

exception lsl.skymap.SkyMapLoadError

Exception raised when a SkyMap fails to load.

exception lsl.skymap.SkyMapPowerError

Exception raised when an operation on a normalized SkyMap fails to compute (such as summing or multiplying over an empty data set).