PhotonsList - EranOfek/AstroPack GitHub Wiki

Description

UNDER CONSTRUCTION

Class Hierarchy: Base -> Component -> PhotonsList

PhotonsList is a class that can be used to store photon time-tagged images (i.e., events list). PhotonsLis objects are arrays and may contain multiple event lists (images). The class includes the basic functionality for working with event lists.

Additional tools that are in the packages: imUtil.poissNoise.

Properties

  • Events - An AstroCatalog object that contains the list of time-tagged photons and their properties (e.g., time, coordinates, energy, flags).

  • BadTimes - A two column matrix of bad times [StartTime, EndTime] to be excluded from the events list.

  • Image - An optional image constructed from events list.

  • X - TBD

  • Y - TBD

  • HeaderData - An AstroHeader object

  • Back - A BackImage object.

  • Mask - A MaskImage object.

  • WCS - A AstroWCS object.

  • ColTime - Name of time column. Default is 'time'.

  • ColEnergy - Name of energy column. Default is 'energy'.

  • ColTDet - Name of Tiled Detector X,Y coordinates. Default is {'tdetx','tdety'}. E.g., a tiled detector, an artificial system to show the whole instrument plane.

  • ColDet - Name of Detector X,Y coordinates. Default is {'detx','dety'}. E.g., detector or mirror coordinates.

  • ColChip - Name of Chip X,Y coordinates. Default is {'chipx','chipy'}. E.g., pixel numbers on ACIS chip or HRC segment.

  • ColSky - Name of sky X,Y coordinates. Default is {'x','y'}. E.g., a pixel plane aligned with ICRS RA and Dec.

Methods

Read FITS files into PhotonsList object:

  • readPhotonsList1 - Read time-tagged photons list from a FITS file into a PhotonsList object. Read also the header and WCS from the header.

Get basic information from PhotonsList:

  • getCol - get the content of a column in the photon list table.
  • nphotons - count photons in an image, including photons in good images.

Find and filter by bad times and energy:

  • populateBadTimes - Identify bad times and populate the bad times property.
  • removeBadTimes - Remove bad times from PhotonsList.
  • selectEnergy - Select photons within some energy ranges.

Create 2-D images from PhotonsList:

  • events2image - Generate an image (by binning) from a list of [X,Y] positions.
  • constructImage - construct image in any coordinate system, and optionally select energy and ccd_id.

Background estimation:

  • background - Estimate Poisson background in PhotonsList image. The background expectancy is estimated by poissfit the counts in the pixels. This is done in 2 iterations. After the first iterations high values are removed.

Photometry and photons from sources:

  • getSrcPhotons - Get photons around sources RA/Dec position. Given a list of RA/Dec or X/Y positions, return all photons around these positions.

Astrometry:

  • xy2sky - Convert X,Y coordinates to RA/Dec. Note that in ds9 these are called detector coordinates, while in the Chandra event file they are called sky.
  • sky2xy - Convert RA/Dec coordinates to X/Y. Note that in ds9 these are called detector coordinates, while in the Chandra event file they are called sky coordinates.
  • addSkyCoo - Add RA/Dec to events list.

Examples: