DavidT3 · jessicapilling · Jun 26, 2026 · Apr 21, 2026 · Apr 21, 2026 · Apr 21, 2026
diff --git a/.gitignore b/.gitignore
@@ -1,9 +1,22 @@
+CLAUDE.md
 /docs/source/notebooks/tutorials/whole_sample.csv
 /docs/source/notebooks/advanced_tutorials/random_brightness_profile.xga
 .coverage
 .pytest_cache
 xga_output
+daxa_output
+*census*
+*blacklist*
+.idea
 .ipynb_checkpoints
+.vscode
+/xga.egg-info/
+*__pycache__*
 /docs/build
-*__pycache__
-xga.egg-info/
+*noupload*
+.DS_Store
+/xga/__pycache__
+*.pyc
+xga/__pycache__/__init__.cpython-39.pyc
+claude_context/
+htmlcov
diff --git a/LICENSE b/LICENSE
@@ -1,6 +1,6 @@
 BSD 3-Clause License
 
-Copyright (c) 2024, David J Turner and the Contributors
+Copyright (c) 2026, David J Turner and the Contributors
 All rights reserved.
 
 Redistribution and use in source and binary forms, with or without

diff --git a/README.md b/README.md
@@ -61,6 +61,9 @@ conda activate <YOUR ENVIRONMENT NAME GOES HERE>
 pip install pyabel==0.9
 ```
 
+> [!IMPORTANT]
+> For Python 3.10 and earlier, the optional dependency [contextlib-chdir](https://pypi.org/project/contextlib-chdir/) must be installed.
+
 ## Required Dependencies
 XGA depends on two non-Python pieces of software:
 * XMM's Science Analysis System (SAS) - Version 17.0.0, but other versions should be largely compatible with the
@@ -90,8 +93,9 @@ Before XGA can be used you must fill out a configuration file (a completed examp
 
 Follow these steps to fill out the configuration file:
 1. Import XGA to generate the initial, incomplete, configuration file.
-2. Navigate to ~/.config/xga and open xga.cfg in a text editor. The .config directory is usually hidden, so it is 
+2. Navigate to ~/.config/xga and open xga.cfg in a text editor. The .config directory is usually hidden, so it is
 probably easier to navigate via the terminal.
+   * Note: The location of the configuration directory can be overridden by setting the ``XGA_CONFIG_DIR`` environment variable. If set, XGA will look for its configuration and store its census files in exactly that directory.
 3. Take note of the entries that currently have /this/is/required at the beginning, without these entries the 
 module will not function.
 4. Set the directory where you wish XGA to save the products and files it generates. I just set it to xga_output,
@@ -136,7 +140,7 @@ If you encounter a bug, or would like to make a feature request, please use the
 [issues](https://github.com/DavidT3/XGA/issues) page, it really helps to keep track of everything.
 
 However, if you have further questions, or just want to make doubly sure I notice the issue, feel free to send
-me an email at turne540@msu.edu
+me an email at djturner@umbc.edu
 
 
 

diff --git a/docs/example_config/xga.cfg b/docs/example_config/xga.cfg
@@ -18,3 +18,11 @@ mos1_expmap = {obs_id}/images/{obs_id}-{lo_en}-{hi_en}keV-mos1_merged_expmap.fit
 mos2_expmap = {obs_id}/images/{obs_id}-{lo_en}-{hi_en}keV-mos2_merged_expmap.fits
 region_file = /home/dt237/apollo_mnt/xmm_obs/code/xapa/id_results/{obs_id}/final_class_regions_REDO.reg
 
+[EROSITA_FILES]
+root_erosita_dir = /home/dt237/apollo_mnt/erosita_obs/data/
+clean_erosita_evts = {obs_id}/clean_evts.fits
+lo_en = ['0.5']
+hi_en = ['2.0']
+erosita_image = {obs_id}/images/{obs_id}_combined_{lo_en}-{hi_en}keVimg.fits
+erosita_expmap = {obs_id}/images/{obs_id}_combined_{lo_en}-{hi_en}keVexpmap.fits
+region_file = /home/dt237/apollo_mnt/erosita_obs/regions/{obs_id}.reg
diff --git a/docs/requirements.txt b/docs/requirements.txt
@@ -21,7 +21,6 @@ corner>=2.2.2
 emcee>=3.1.6
 tabulate>=0.9.0
 getdist>=1.4.7
-pytest>=6.2.5
 cycler>=0.11.0
 exceptiongroup>=1.0.4
 importlib_resources~=6.5.2
diff --git a/docs/source/conf.py b/docs/source/conf.py
@@ -1,5 +1,5 @@
-#  This code is a part of X-ray: Generate and Analyse (XGA), a module designed for the XMM Cluster Survey (XCS).
-#  Last modified by David J Turner (turne540@msu.edu) 20/02/2023, 14:04. Copyright (c) The Contributors
+#  This code is part of X-ray: Generate and Analyse (XGA), a module designed for the XMM Cluster Survey (XCS).
+#  Last modified by David J Turner (djturner@umbc.edu) 4/27/26, 11:03 AM. Copyright (c) The Contributors.
 
 # Configuration file for the Sphinx documentation builder.
 #
@@ -16,8 +16,6 @@
 import os
 import sys
 sys.path.insert(0, os.path.abspath('../..'))
-import shutil
-
 
 # -- Extra Setup for XGA -----------------------------------------------------
 
@@ -38,32 +36,11 @@
     # As this file lives in the docs/source folder, we go two levels up for the absolute path the XGA repo folder
     xga_path = '/'.join(current_path.split('/')[:-2])
 
-    # The test data includes a mostly complete config file, and census
-    test_cfg_path = os.path.join(xga_path, 'tests', 'test_data', 'xga.cfg')
-    test_census_path = os.path.join(xga_path, 'tests', 'test_data', 'census.csv')
-    test_data_path = os.path.join(xga_path, 'tests', 'test_data')
-
-    # Copy the config and census over to the place they should be on whatever system is building this
-    shutil.copy(test_cfg_path, config_file_path)
-    shutil.copy(test_census_path, census_file_path)
-
-    with open(config_file_path, 'r') as cfg:
-        lines = cfg.readlines()
-
-    lines = [line.replace('root_xmm_dir = ./', 'root_xmm_dir = {}'.format(test_data_path)) for line in lines]
-
-    with open(config_file_path, 'w') as cfg:
-        cfg.write(''.join(lines))
-
-# I don't like to import in the code itself, but it has to be here so we can be sure a valid config file exists
-# from xga import utils
-# utils.XGA_MODE = "DOCS"
-
 # -- Project information -----------------------------------------------------
 
 project = 'X-ray: Generate and Analyse (XGA)'
-copyright = '2022, David J Turner'
-author = 'David J Turner'
+copyright = '2026, The Contributors'
+author = 'David J Turner, XGA Team'
 
 # The full version, including alpha/beta/rc tags
 # release = '0.1'

diff --git a/docs/source/future.rst b/docs/source/future.rst
@@ -1,20 +1,15 @@
 Planned XGA Features
 ========================
 
-* **Upper Limit X-ray Luminosities** - These luminosities are measured from photometric products when there are not sufficient X-ray counts to generate a spectrum. This will involve integrating a tool that I have already written for XCS into the structure of XGA, though rather than measuring upper limit luminosities from a single image, I intend to measure them from the combined data.
+* **Support for other X-ray telescopes** - XGA's purpose is to facilitate the exploitation of the complete public X-ray archive, hence the aim is to support all X-ray telescopes eventually. Currently XMM and eROSITA are supported, and the software is setup so that integrating new telescope-specific softwares should not be an arduous task. If you are interested in integrating a telescope into XGA please reach out to the development team (:doc:`support`). 
 
-* **Source Finder** - It is likely that I will extend my Hierarchical Clustering Peak Finder into a full source finder, as well as completing the implementation of a convolutional peak finder/source finder, which was inspired by my friend and colleague Lucas Porth.
+* **Creating a Docker image for users to download** - Creating a Docker environment with all relevant software already installed.
 
-* **More XSPEC Models** - Including a two temperature APEC model, and support for custom user defined models.
+* **More XSPEC Models** - Support for custom user defined models.
 
-* **Implement emcee scaling relation fitter** - What it says on the tin really. Implement an emcee fitter for the scaling relations so that there is an MCMC option that doesn't require the installation of a bunch of optional dependencies.
+* **Upper Limit X-ray Luminosities** - These luminosities are measured from photometric products when there are not sufficient X-ray counts to generate a spectrum. This will support measurements from combined data, as well as single images. 
 
-* **Ability to save ScalingRelation objects** - The ability to save ScalingRelation objects to disk in some way, so that code to generate them doesn't need to be run multiple times.
-
-* **Support for other X-ray telescopes** - Support for generation and analysis of data products from other telescopes.
-
-* **Creating a Docker image for users to download** - Creating a Docker environment with SAS and HEASoft already installed, for ease of use.
+* **Implement emcee scaling relation fitter** - Implement an emcee fitter for the scaling relations so that there is an MCMC option that doesn't require the installation of optional dependencies.
 
 * **Method for finding poorly removed point sources** - An attempt to mitigate occasional mistakes by source finders that produce regions that don't necessarily remove the entire point source.
 
-* **Overdensity radius measurement** - Using HydrostaticMass profiles to measure the overdensity radius of a cluster.
diff --git a/docs/source/images/flowchart.png b/docs/source/images/flowchart.png
diff --git a/docs/source/images/mulitmission.png b/docs/source/images/mulitmission.png
diff --git a/docs/source/install.rst b/docs/source/install.rst
@@ -2,13 +2,13 @@ Installing and Configuring XGA
 ==============
 
 This is a slightly more complex installation than many Python modules, but shouldn't be too difficult. If you're
-having issues feel free to contact me.
+having issues feel free to get in contact (see :doc:`Getting Help` section).
 
 Data Required For Using This Module
 -----------------------------------
 
-**This is very important** - Currently, to make use of this module, you **must** have access to cleaned XMM-Newton
-event lists, as XGA is not yet capable of producing them itself.
+**This is very important** - Currently, to make use of this module, you **must** have access to **either** cleaned XMM-Newton or eROSITA
+event lists. For aquiring and cleaning X-ray data, the Python module `DAXA <https://github.com/DavidT3/DAXA>`_ is recommended.
 
 Region Files
 ------------
@@ -50,19 +50,29 @@ We also provide a Conda lock file in the conda_envs directory (see `conda-lock G
     conda activate <YOUR ENVIRONMENT NAME GOES HERE>
     pip install pyabel==0.9
 
+.. important::
+    For Python 3.10 and earlier, the optional dependency `contextlib-chdir <https://pypi.org/project/contextlib-chdir/>`_ must be installed.
+
 Required Dependencies
 ---------------------
 
-XGA depends on two non-Python pieces of software:
+XGA depends on some non-Python pieces of software, dependent on the telescope from which your data originates:
+
+For all telescopes:
+    * HEASoft's XSPEC - Version 12.10.1 - It isn't guaranteed later versions will work.
 
+For XMM data:
     * XMM's Science Analysis System (SAS) - Version 17.0.0, but other versions should be largely compatible with the software. SAS version 14.0.0 however, does not support features that PSF correction of images depends on.
-    * HEASoft's XSPEC - Version 12.10.1 - I can't guarantee later versions will work.
+
+For eROSITA data:
+    * eROSITA Science Analysis Software System (eSASS) - EDR version. It must be installed on the system, we do not support interaction through a Docker container.
 
 All required Python modules can be found in requirements.txt, and should be added to your system during the installation of XGA.
 
-Excellent installation guides for `SAS <https://www.cosmos.esa.int/web/xmm-newton/sas-installation>`_ and
-`HEASoft <https://heasarc.gsfc.nasa.gov/lheasoft/install.html>`_ already exist, so I won't go into that here.
-XGA will not generate XMM products without detecting SAS, and will not fit spectra without detecting XSPEC.
+Excellent installation guides for `SAS <https://www.cosmos.esa.int/web/xmm-newton/sas-installation>`_,
+`HEASoft <https://heasarc.gsfc.nasa.gov/lheasoft/install.html>`_, and `eSASS <https://erosita.mpe.mpg.de/edr/DataAnalysis/esassinstall.html>`_ already exist, please see them for detailed installation instructions.
+XGA will not generate XMM products without detecting SAS, or generate eROSITA products without detecting eSASS, or fit
+spectra without detecting XSPEC.
 
 Optional Dependencies
 ---------------------
@@ -85,35 +95,62 @@ Before XGA can be used you must fill out a configuration file (a completed examp
 Follow these steps to fill out the configuration file:
 
 1. Import XGA to generate the initial, incomplete, configuration file.
+   * Note: XGA uses a **lazy loading** architecture. Importing the module does not perform any filesystem checks or software discovery immediately. These only occur when a configuration variable or data-dependent function is first accessed.
 2. Navigate to ~/.config/xga and open xga.cfg in a text editor. The .config directory is usually hidden, so it is probably easier to navigate via the terminal.
+   * Note: The location of the configuration directory can be overridden by setting the ``XGA_CONFIG_DIR`` environment variable. If set, XGA will look for its configuration and store its census files in exactly that directory. Because of XGA's lazy loading, you can even set this environment variable **after** importing XGA in a session.
+   * Note: If you need to switch configuration directories mid-session, you can use the ``reinitialise_xga()`` function:
+
+   .. code-block:: python
+
+       import xga
+       # Change to a new config directory
+       xga.reinitialise_xga('/path/to/new/config/')
 3. Take note of the entries that currently have /this/is/required at the beginning, without these entries the module will not function.
-4. Set the directory in which XGA will save the products and files it generates. I just set it to xga_output, so wherever I run a script that imports XGA it will create a folder called xga_output there. You could choose to use an absolute path and have a global XGA folder however, it would make a lot of sense.
+4. Set the directory in which XGA will save the products and files it generates. It is advised to just set it to xga_output, so wherever you run a script that imports XGA it will create a folder called xga_output there. You could choose to use an absolute path and have a global XGA folder however, it wouldn't make a lot of sense.
 5. You may also set an optional parameter in the [XGA_SETUP] section, 'num_cores'. If you wish to manually limit the number of cores that XGA is allowed to use, then set this to an integer value, e.g. num_cores = 10. You can also set this at runtime, by importing NUM_CORES from xga and setting that to a value.
-6. The root_xmm_dir entry is the path of the parent folder containing all of your observation data.
+6. The root_<telescope>_dir entry is the path of the parent folder containing all of your observation data for <telescope>. It is not necessary to have data for all telescopes that XGA supports.
 7. Most of the other entries tell XGA how different files are named. clean_pn_evts, for instance, gives the naming convention for the cleaned PN events files that XGA generates products from.
 8. Bear in mind when filling in the file fields that XGA uses the Python string formatting convention, so **anywhere you see {obs_id} will be filled formatted with the ObsID of interest when XGA is actually running**.
 9. The lo_en and hi_en entries can be used to tell XGA what images and exposure maps you may already have. For instance, if you already had 0.50-2.00keV and 2.00-10.00keV images and exposure maps, you could set lo_en = ['0.50', '2.00'] and hi_en = ['2.00', '10.00'].
 10. Finally, the region_file entry tells XGA where region files for each observation are stored (if they exist).
 
-**Disclaimer: If region files are supplied, XGA also expects at least one image per instrument per observation, for WCS information.**
+**Disclaimer: If region files are supplied for XMM data, XGA also expects at least one image per instrument per observation, for WCS information.**
 
-I have tried to make this section as general as possible, but I am biased by how my research group generates and
+This section aims to be as general as possible, but is biased by how our research group generates and
 stores our data products. If you are an X-ray astronomer who wishes to use this module, but it seems to be incompatible
 with your setup, please get in touch or raise an issue.
 
-**Remote Data Access:** If your data lives on a remote server, and you want to use XGA on a local machine, I recommend
-setting up an SFTP connection and mounting the server as an external volume. Then you can fill out the configuration
-file with paths going through the mount folder - its how I use it a lot of the time.
+**Remote Data Access:** If your data lives on a remote server, and you want to use XGA on a local machine, it is recommended
+to set up an SFTP connection and mounting the server as an external volume. Then you can fill out the configuration
+file with paths going through the mount folder.
+To mount a server, one can follow the steps detailed in this `guide <https://sftptogo.com/blog/how-to-mount-sftp-as-a-drive-on-mac/>`_.
 
 XGA's First Run After Configuration
 -----------------------------------
 
-The first time you import any part of XGA, it will create an 'observation census', where it will search through
+The first time you access any configuration-dependent part of XGA, it will create an 'observation census', where it will search through
 all the observations it can find (based on your entries in the configuration file), check that there are events
 lists present, and record the pointing RA and DEC. *This can take a while*, but will only take that long on the first
-run. The module will check the census against your observation directory and see if it needs to be updated on
+run. This process is fully parallelized and will utilize your available CPU cores to speed up the filesystem I/O.
+
+The module will check the census against your observation directory and see if it needs to be updated on
 every run.
 
+Census Management
+-----------------
+
+XGA provides the ``rebuild_census()`` function for manual management of the observation census. This is useful if you have deleted data from your disk or want to force a fresh scan of your archives.
+
+*   **Standard Update**: Calling ``rebuild_census()`` without arguments is equivalent to the update check performed at startup.
+*   **Full Rebuild**: ``rebuild_census(full_rebuild=True)`` deletes the existing census and parses every FITS header from scratch.
+*   **Cleanup**: ``rebuild_census(clean_dead=True)`` checks the current census against the filesystem and removes entries for ObsIDs that no longer exist.
+
+.. code-block:: python
+
+    import xga
+    # Prune census entries for data that has been deleted from disk
+    xga.rebuild_census(clean_dead=True)
+
 Blacklisting ObsIDs
 -------------------