Stacking Swift/XRT Data (PC Mode) (swift-stack-pc)#

Pipeline module to run Swift/XRT processing in PC Mode across multiple epochs and stack time-binned products.

Automates the stacking workflow:

  1. Executes xrtpipeline for each epoch listed in a text file, producing calibrated event and image files.

  2. Bins the resulting event (.evt) and image (.img) files into time intervals (days since explosion) defined by user.

  3. Stacks events and images in each bin into dedicated subdirectories under ./stacks/, named by their first–last epochs/observation id.

  4. Updates the stacked event files MJD-BEG and MJD-END headers.

Caution

The user must make sure to run this script on the parent of "sources" directory and the "sources" directory has the downloaded data with ObsId as its child directory. E.g.

parent
├── sources
│   ├── ObsId1 # downloaded from Swift/XRT raw data
│   ├── ObsId2
|   ├── ObsId3
|   └── ObsId4

When swift-stack-pc is run inside parent directory, it will result in

parent
├── sources
│   ├── ObsId1
│   ├── ObsId2
|   ├── ObsId3
|   └── ObsId4
├── output
│   ├── ObsId1
│   ├── ObsId2
|   ├── ObsId3
|   └── ObsId4
├── stack
│   ├── ObsId1_to_ObsId2
│   └── ObsId3_to_ObsId4
Arguments:
--epochs

File listing one epoch/obsid identifier per line.

--bin-size

Time-bin width in days (default: 1.0).

--explosion-mjd

Supernova time of explosion in MJD.

--src-ra

Source ICRS RA (decimal degrees).

--src-dec

Source ICRS Dec (decimal degrees).

--pn-tra

(Optional) PN attitude RA override (default: POINT).

--pn-dec

(Optional) PN attitude Dec override (default: POINT).

--help

Show help message

Output:

  • The same output of xrtpipeline in ./output/ directory.

  • ./stacks/ directory with their first–last epochs/observation id to be the subdirectories.

  • Inside the subdirectories of ./stacks/, there will be a cleaned evt file (format: evt_{obsid1}to{obsid2}.evt) and exposure image file (format: img_{obsid1}to{obsid2}.img).

Usage formula:
>>> swift-stack-pc [--epochs] [--bin-size] [--explosion-mjd] \
        [--src-ra] [--src-dec] [--pn-tra] [--pn-dec]
Usage examples:
>>> swift-stack-pc --epochs source_epochs.txt \
...    --bin-size 2.0 \
...    --explosion-mjd 59000.5 \
...    --src-ra <RA> \
...    --src-dec <Dec> \
>>> swift-stack-pc --epochs ./path/to/epochs.txt \
...    --explosion-mjd 59000.5 \
...    --src-ra <RA> \
...    --src-dec <Dec> \
Requirements: