Catalogs and Sky Map

Catalogs

New in version 0.2.

LWA astronomical source catalogs.

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.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.

abstract parse_file()

Read catalog information from file into internal data structures.

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.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.

class lsl.catalog.PKS_Catalog

Specific definition for PKS source catalog.

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.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.F2FGL_Catalog

Specific definition for Fermi LAT 2-year point source catalog.

parse_file()

Read a source catalogue data file.

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(name)

Returns a Catalog object representing the catalog given by name.

classmethod get_names()

Return a list of known catalog names.

Sky Map

New in version 0.2.

Classes and methods to model sky brightness and visibility.

Changed in version 1.2.0: Removed the orignal SkyMap class that uses LFmap at 73.9 MHz Updated SkyMapGSM to use the actual GSM rather than a fit to the GSM Added a new SkyMapLFSM that uses the 5.1 degree resolution LFSM

class lsl.skymap.SkyMapGSM(filename=None, freq_MHz=73.9)

Extension of the SkyMap class to use the Global Sky Model.

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

Note

This class uses a slightly different interpolation method than the original GSM and introduces a few percent difference at 74 MHz.

Changed in version 1.2.0: Reworked the GSM model to use the actual GSM that has been downsampled to 64 sides rather than the fit.

compute_total_power()

Compute and return the the total power from the sky.

normalize_power()

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

class lsl.skymap.SkyMapLFSM(filename=None, freq_MHz=73.9)

Extension of the SkyMap class to use the Low Frequency Sky Model with 5.1 degree resolution.

For more information on the Low Frequency Sky Model, see: https://lda10g.alliance.unm.edu/LWA1LowFrequencySkySurvey/

New in version 1.2.0.

compute_total_power()

Compute and return the the total power from the sky.

normalize_power()

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

class lsl.skymap.ProjectedSkyMap(skymap_object, 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. get_direction_cosines - Computes the direction cosines 3. compute_visibile_power - Sums the power for all visible sources in the sky.

compute_visible_power()

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

get_direction_cosines()

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