BackgroundPrior#

class jinwu.background.BackgroundPrior(n_off_prior: float, t_off: float, area_ratio: float)[source]#

Bases: object

Background prior based on OFF-region total counts over a known exposure.

n_off_prior#

Total counts observed in the OFF region during t_off seconds.

Type:

float

t_off#

Exposure time in the OFF region corresponding to n_off_prior (seconds).

Type:

float

area_ratio#

A_on / A_off. The Li&Ma alpha uses alpha = area_ratio * (t_on / t_off).

Type:

float

Methods Summary

alpha(t_on)

from_epwxt_background(fits_path, *[, ...])

Construct BackgroundPrior from a single EP/WXT background FITS file that contains counts per cm^2 accumulated over a reference exposure (typically 1e6 s).

from_epwxt_background_default(*[, chan_lo, ...])

Return the ready-made BackgroundPrior values as requested by user.

Methods Documentation

alpha(t_on: float) → float[source]#
classmethod from_epwxt_background(fits_path: str, *, chan_lo: int = 53, chan_hi: int = 506, arf_path: str | None = None, arf_bin_lo: int = 81, arf_bin_hi: int = 780, pixel_size_mm: float = 0.015, pixel_fov_deg: float = 0.00229, src_radius_arcmin: float = 9.0, bkg_rin_arcmin: float = 18.0, bkg_rout_arcmin: float = 36.0, t_off: float = 1000000.0, verbose: bool = True) → BackgroundPrior[source]#

Construct BackgroundPrior from a single EP/WXT background FITS file that contains counts per cm^2 accumulated over a reference exposure (typically 1e6 s).

This enforces the energy band via detector channels [chan_lo, chan_hi] (default 53–506, about 0.5–4.0 keV), computes the OFF-region prior counts in a desired t_off, and derives area_ratio from instrument geometry.

Parameters:

  • fits_path (str) – Path to the background FITS (counts per cm^2). In practice only one combined background file is available.

  • chan_lo (int) – Inclusive channel bounds to approximate 0.5–4.0 keV.

  • chan_hi (int) – Inclusive channel bounds to approximate 0.5–4.0 keV.

  • pixel_size_mm (float) – Pixel size on detector (mm). Default 0.015 mm.

  • pixel_fov_deg (float) – Sky angular size per pixel (degree). Default 0.00229 deg.

  • src_radius_arcmin (float) – Source region radius (arcmin). Default 9’.

  • bkg_rin_arcmin (float) – Background annulus inner/outer radii (arcmin). Default 18’–36’.

  • bkg_rout_arcmin (float) – Background annulus inner/outer radii (arcmin). Default 18’–36’.

  • t_off (float) – OFF prior exposure (s) for Li&Ma. Default 1e6 s (matches FITS by default).

  • verbose (bool) – Print brief diagnostics.

Return type:

BackgroundPrior

classmethod from_epwxt_background_default(*, chan_lo: int = 53, chan_hi: int = 506, t_off: float = 1000000.0, verbose: bool = True) → BackgroundPrior[source]#

Return the ready-made BackgroundPrior values as requested by user. Ignores file IO and outputs fixed values for reproducibility of quick tests.