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.
- abstract 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(name)¶
Returns a Catalog object representing the catalog given by name.
- classmethod get_names()¶
Return a list of known catalog names.
- 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.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.
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.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:
_init_ - takes the array coordinate filename as an input argument.
get_direction_cosines - Computes the direction cosines
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).
- class lsl.skymap.SkyMapBase(filename=None, freq_MHz=73.9)¶
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:
_init_ - takes the array coordinate filename as an input argument.
- normalize_power - Converts the skymap powers (in Kelvin radiated into 4 pi
ster) into a power seen at the antenna.
compute_total_power - Sums the power for all sources in the sky
- ScaleSourcePowerstoFrequency - Scales the skymap from the base 73.8 MHz to
the desired frequency.
- 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.SkyMapGSM(filename=None, freq_MHz=73.9)¶
Extension of the SkyMapBase 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 SkyMapBase 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.