Merge pull request #9 from radionets-project/beam2jansky

Beam2jansky

docs/changes/9.feature.rst

@@ -0,0 +1 @@
+- Add utility function `radiotools.utils.img2jansky` that converts an image in Jy/beam to Jy/px

radiotools/utils/__init__.py

@@ -1,3 +1,3 @@
-from .utils import get_array_names
+from .utils import get_array_names, img2jansky
 
-__all__ = ["get_array_names"]
+__all__ = ["get_array_names", "img2jansky"]

radiotools/utils/utils.py

@@ -1,5 +1,8 @@
+import numpy as np
 import requests
+from astropy.io import fits
 from bs4 import BeautifulSoup
+from numpy.typing import ArrayLike
 
 
 def get_array_names(url: str) -> list[str]:
@@ -30,3 +33,27 @@ def get_array_names(url: str) -> list[str]:
     layouts = list(set(layouts))
 
     return layouts
+
+
+def img2jansky(image: ArrayLike, header: fits.Header):
+    """Converts an image from Jy/beam to Jy/px.
+
+    Parameters
+    ----------
+    image : array_like
+        Input image that is to be converted.
+    header : :class:`astropy.io.fits.header.Header`
+        FITS file header belonging to the respective image.
+
+    Returns
+    -------
+    array_like
+        Converted image in units of Jy/px.
+    """
+    return (
+        4
+        * image
+        * np.log(2)
+        * np.power(header["CDELT1"], 2)
+        / (np.pi * header["BMIN"] * header["BMAJ"])
+    )