ACCarnall/bagpipes ? reverse-engineered prompt

Build me a Python tool for doing Bayesian fits to galaxy spectra and photometry, where I can generate realistic model galaxy spectra and compare them to observed data.

I want it to be installable with pip and usable from normal Python scripts or notebooks, with clear examples for fitting both spectroscopy and photometry. It should support a default nested sampling workflow, and if a faster third party sampler is available it should use that automatically, but still work without extra setup. Please make the package feel ready for real astronomy use, with sensible defaults, documented inputs and outputs, and example workflows for common galaxy fitting tasks.

If anything about the latest recommended usage or dependencies is unclear, look up the current docs online and match the project’s intended behavior. Also include a simple way to cite the main papers in the README or docs so people know how to reference it properly.