Dataset for "A NICER View of PSR J0030+0451: Updated Constraints from Six Years of NICER Observations"

README
======

Data for: A NICER View of PSR J0030+0451: Updated Constraints from Six Years of NICER Observations
Kini et al. (2026) -- Submitted to The Astrophysical Journal

SOFTWARE
--------

All inference runs were performed using X-PSI version 3.1.0.
All post-processing was performed using X-PSI version 3.1.6.

To exactly reproduce Figure 3, replace the file xpsi/PostProcessing/_corner.py
in your X-PSI installation with the _corner.py file provided in Files/ before
running the corresponding notebook.

The notebooks should run without any modifications.

HOTSPOT NAMING CONVENTION
--------------------------

Throughout the paper (Tables 1 and 2, Figure 3), we adopt a consistent
transformed hotspot representation in which the hot region with the smaller
colatitude is labeled as the secondary component, with corresponding
transformations applied to the superseding/ceding labels and phases.

Note that the inference itself was performed in the native X-PSI
parameterization, in which the hot region with the smaller colatitude is labeled
as the primary component. The MultiNest output files in the Outputs/ folder are
therefore in the native parameterization. Users who require the maximum a
posteriori (MAP) or maximum-likelihood (ML) parameter vectors in the native
X-PSI parameterization should retrieve them directly from those MultiNest
output files.

REPOSITORY STRUCTURE
---------------------

1. mass_radius_contours/

   Mass-radius posterior samples and credible contours for the PDT-U model.

   weighted_samples_PDTU.txt
      Column 0 -- Sample weight
      Column 1 -- Mass [M_sun]
      Column 2 -- Radius [km]

   equal_weight_samples_PDTU.txt
      Column 0 -- Mass [M_sun]
      Column 1 -- Radius [km]

   contours_PDTU_MR_68.txt
      Column 0 -- Radius [km]
      Column 1 -- Mass [M_sun]  (68% credible contour)

   contours_PDTU_MR_95.txt
      Column 0 -- Radius [km]
      Column 1 -- Mass [M_sun]  (95% credible contour)

  contours_PDTU_MR_99.txt
         Column 0 -- Radius [km]
         Column 1 -- Mass [M_sun]  (99% credible contour)

2. Files/

   Files/Figures/
      Jupyter notebooks used to produce all figures in the paper. Notebook names
      are self-explanatory and correspond to the figures they generate. All
      notebooks should run without modification.

   Files/J0030_products/
      Reduced observational data products.

      NICER:
         Event file:   NICER/merged_cut.evt
         ARF:          NICER/merged_cutmpu7.arf
         RMF:          NICER/merged_cutmpu7.rmf
         V24 dataset (required to reproduce Figure 1):
                       NICER_J0030_evt_30to299_exposure1936864_preprocessed_v006.txt

      XMM-Newton (MOS1 and MOS2):
         Spectra:          XMM/MOS{1,2}/j0030_merged_spec_mos{1,2}.txt
         Response matrices: XMM/MOS{1,2}/j0030_merged_resp_uncomp_mos{1,2}.txt
         Background files: XMM/MOS{1,2}/j0030_merged_bkg_mos{1,2}.txt
         Channel-to-energy mapping (shared):
                           XMM/j0030_merged_channel-energy_mapping_mos12.txt

3. STPDT_modules/ and PDTU_modules/

   Python modules used for both inference and post-processing, for the ST+PDT
   and PDT-U models respectively. These include the CustomPrior classes and the
   transformed prior definitions used to swap hot region labels during plotting
   (see hotspot naming convention above).

4. Outputs/

   MultiNest output files for all runs presented in the paper, organized by
   model (PDT-U and ST+PDT). Also includes the MultiNest outputs from V24
   (see also :https://doi.org/10.5281/zenodo.8239000) to make the repository fully self-contained.

5. Model_data/

   Atmosphere and interstellar absorption tables required to run X-PSI.

   model_data/nsx_H_v200804.out
      NSX fully-ionized, non-magnetic hydrogen atmosphere emergent intensity
      table (Ho & Lai 2001; Ho & Heinke 2009). This file was previously
     distributed in the earlier Zenodo release (https://doi.org/10.5281/zenodo.4697625),
     which included W. C. G. Ho as co-author.

   model_data/interstellar_phot_frac.txt
      Interstellar attenuation fraction table at a fiducial column density.

6. mass_radius_contours_old/

   Mass-radius credible contours for the comparison sources used in Figure 4.

      PSR J0740+6620   -- Salmi et al. (2024)
      PSR J0030+0451   -- Vinciguerra et al. (2024) (V24)
      PSR J0437-4715   -- Choudhury et al. (2024)
      PSR J0614-3329   -- Mauviard et al. (2025)

REFERENCES
----------

Ho, W. C. G., & Lai, D. 2001, MNRAS, 327, 1081
Ho, W. C. G., & Heinke, C. O. 2009, Nature, 462, 71
Vinciguerra, S., Salmi, T., Watts, A. L., et al. 2024, ApJ, 961, 62
Choudhury, D., Salmi, T., Vinciguerra, S., et al. 2024, ApJL, 971, L20
Salmi, T., Choudhury, D., Kini, Y., et al. 2024, ApJ, 974, 294
Mauviard, L., Guillot, S., Salmi, T., et al. 2025, ApJ, 995, 60
Riley, T. E., Choudhury, D., Salmi, T., et al. 2023, JOSS, 8, 4977