README.md

---
license: cc-by-4.0
task_categories:
- image-to-image
tags:
- astronomy
- supernovae
- panstarrs
- delight
size_categories:
- 1K<n<10K
---

## Description

This is the dataset from DELIGHT [1], a model that locates the host galaxy of a
transient from multi-resolution images. The difference with the original is that
the images are **not** the cutouts used in the paper: they were regenerated from
[hips2fits](https://alasky.cds.unistra.fr/hips-image-services/hips2fits)
(PanSTARRS DR1 HiPS, served by CDS).

It contains **9,246 examples**, built by **autolabeling**: transient positions are
**simulated**, not observed. For each of the 7,093 host galaxies in
[h2f_delight_train](https://huggingface.co/datasets/PRISM-Astro/h2f_delight_train),
positions are drawn **uniformly** inside the elliptical footprint of its r-band
Sérsic fit, truncated at 3·Re.

This is exactly how
[h2f_delight_autolabeling_1pct](https://huggingface.co/datasets/PRISM-Astro/h2f_delight_autolabeling_1pct)
was built. **The only difference is how many positions each galaxy gets**, and
that is what the `radius_norm` name refers to.


## The rule

Bigger galaxies generate more examples:

```
n = max(1, round((Re / Re0) ** p))        Re0 = 12 arcsec,  p = 6
```

`Re0` is the size at which a galaxy starts generating more than one example.
Below it, a galaxy contributes exactly one. **No galaxy is ever dropped**: all
7,093 are present, and 96.9 % of them contribute a single example. Only 223
galaxies (3.1 %) contribute more, up to 82 for the largest one.

## Why those numbers

The count of galaxies large enough to reach a given distance drops very fast:
2,912 reach 10 arcsec, 499 reach 30, and only 27 reach 60. Raising the count to
a power compensates that drop, and `p = 6` with `Re0 = 12` is the pair that
flattened the histogram best in a grid search over both.

They are **not universal constants**: they were fitted to the size distribution
of this catalog and must be recomputed for a different survey.

## Image format

`image` has shape `(9246, 5, 1, 30, 30)`, which maps to
`(examples, resolution levels, photometric bands, height, width)`. Only the
**r band** was downloaded, hence the size-1 band dimension.

## Columns

<div style="font-family:-apple-system,BlinkMacSystemFont,'Segoe UI',Roboto,sans-serif;max-width:1000px;margin:0 auto;padding:16px 0">
<table style="width:100%;border-collapse:collapse;font-size:13px">
<thead><tr>
<th style="padding:10px 7px;text-align:left;font-weight:600;border-bottom:2px solid #4a6fb5;color:#4a6fb5;font-size:14px;width:18%">Column</th>
<th style="padding:10px 7px;text-align:left;font-weight:500;border-bottom:2px solid #4a6fb5;color:#4a6fb5;font-size:14px;width:20%">Type</th>
<th style="padding:10px 7px;text-align:left;font-weight:500;border-bottom:2px solid #4a6fb5;color:#4a6fb5;font-size:14px">Description</th>
</tr></thead>
<tbody>

<tr><td colspan="3" style="padding:8px 12px;font-weight:600;color:#4a6fb5;border-bottom:1px solid rgba(74,111,181,0.25);background:rgba(74,111,181,0.12)">Image and label</td></tr>
<tr>
<td style="padding:7px 7px;padding-left:20px;border-bottom:1px solid rgba(128,128,128,0.15)"><code>image</code></td>
<td style="padding:7px 7px;border-bottom:1px solid rgba(128,128,128,0.15)"><code>(5,1,30,30)</code> float32</td>
<td style="padding:7px 7px;border-bottom:1px solid rgba(128,128,128,0.15)">Multi-resolution PanSTARRS r-band cutout, centered on the simulated transient position.</td>
</tr>
<tr>
<td style="padding:7px 7px;padding-left:20px;border-bottom:1px solid rgba(128,128,128,0.15)"><code>host_pos</code></td>
<td style="padding:7px 7px;border-bottom:1px solid rgba(128,128,128,0.15)">float32 &times; 2</td>
<td style="padding:7px 7px;border-bottom:1px solid rgba(128,128,128,0.15)">Offset <code>[x, y]</code> from the simulated transient to the host galaxy, in level-0 pixels.</td>
</tr>
<tr><td colspan="3" style="padding:8px 12px;font-weight:600;color:#4a6fb5;border-bottom:1px solid rgba(74,111,181,0.25);background:rgba(74,111,181,0.12)">Identification</td></tr>
<tr>
<td style="padding:7px 7px;padding-left:20px;border-bottom:1px solid rgba(128,128,128,0.15)"><code>oid</code></td>
<td style="padding:7px 7px;border-bottom:1px solid rgba(128,128,128,0.15)">string</td>
<td style="padding:7px 7px;border-bottom:1px solid rgba(128,128,128,0.15)">Identifier of the real transient this galaxy came from. Repeats across the draws of the same galaxy.</td>
</tr>
<tr>
<td style="padding:7px 7px;padding-left:20px;border-bottom:1px solid rgba(128,128,128,0.15)"><code>host_name</code></td>
<td style="padding:7px 7px;border-bottom:1px solid rgba(128,128,128,0.15)">string</td>
<td style="padding:7px 7px;border-bottom:1px solid rgba(128,128,128,0.15)">Catalog name of the host galaxy.</td>
</tr>

<tr><td colspan="3" style="padding:8px 12px;font-weight:600;color:#4a6fb5;border-bottom:1px solid rgba(74,111,181,0.25);background:rgba(74,111,181,0.12)">Host galaxy</td></tr>
<tr>
<td style="padding:7px 7px;padding-left:20px;border-bottom:1px solid rgba(128,128,128,0.15)"><code>host_redshift</code></td>
<td style="padding:7px 7px;border-bottom:1px solid rgba(128,128,128,0.15)">float64</td>
<td style="padding:7px 7px;border-bottom:1px solid rgba(128,128,128,0.15)">Redshift of the host; <code>NaN</code> when unknown.</td>
</tr>
<tr>
<td style="padding:7px 7px;padding-left:20px;border-bottom:1px solid rgba(128,128,128,0.15)"><code>hostsize</code></td>
<td style="padding:7px 7px;border-bottom:1px solid rgba(128,128,128,0.15)">float64</td>
<td style="padding:7px 7px;border-bottom:1px solid rgba(128,128,128,0.15)">Angular size of the host galaxy from the catalog.</td>
</tr>
<tr>
<td style="padding:7px 7px;padding-left:20px;border-bottom:1px solid rgba(128,128,128,0.15)"><code>host_ra</code></td>
<td style="padding:7px 7px;border-bottom:1px solid rgba(128,128,128,0.15)">float64</td>
<td style="padding:7px 7px;border-bottom:1px solid rgba(128,128,128,0.15)">Right ascension of the host, in degrees.</td>
</tr>
<tr>
<td style="padding:7px 7px;padding-left:20px;border-bottom:1px solid rgba(128,128,128,0.15)"><code>host_dec</code></td>
<td style="padding:7px 7px;border-bottom:1px solid rgba(128,128,128,0.15)">float64</td>
<td style="padding:7px 7px;border-bottom:1px solid rgba(128,128,128,0.15)">Declination of the host, in degrees.</td>
</tr>
<tr><td colspan="3" style="padding:8px 12px;font-weight:600;color:#4a6fb5;border-bottom:1px solid rgba(74,111,181,0.25);background:rgba(74,111,181,0.12)">Real transient position</td></tr>
<tr>
<td style="padding:7px 7px;padding-left:20px;border-bottom:1px solid rgba(128,128,128,0.15)"><code>meanra</code></td>
<td style="padding:7px 7px;border-bottom:1px solid rgba(128,128,128,0.15)">float64</td>
<td style="padding:7px 7px;border-bottom:1px solid rgba(128,128,128,0.15)">Mean right ascension of the real transient, in degrees. Not the center of this cutout.</td>
</tr>
<tr>
<td style="padding:7px 7px;padding-left:20px;border-bottom:1px solid rgba(128,128,128,0.15)"><code>meandec</code></td>
<td style="padding:7px 7px;border-bottom:1px solid rgba(128,128,128,0.15)">float64</td>
<td style="padding:7px 7px;border-bottom:1px solid rgba(128,128,128,0.15)">Mean declination of the real transient, in degrees. Not the center of this cutout.</td>
</tr>
<tr>
<td style="padding:7px 7px;padding-left:20px;border-bottom:1px solid rgba(128,128,128,0.15)"><code>sn_ra</code></td>
<td style="padding:7px 7px;border-bottom:1px solid rgba(128,128,128,0.15)">float64</td>
<td style="padding:7px 7px;border-bottom:1px solid rgba(128,128,128,0.15)">Right ascension of the real supernova, in degrees.</td>
</tr>
<tr>
<td style="padding:7px 7px;padding-left:20px;border-bottom:1px solid rgba(128,128,128,0.15)"><code>sn_dec</code></td>
<td style="padding:7px 7px;border-bottom:1px solid rgba(128,128,128,0.15)">float64</td>
<td style="padding:7px 7px;border-bottom:1px solid rgba(128,128,128,0.15)">Declination of the real supernova, in degrees.</td>
</tr>
<tr><td colspan="3" style="padding:8px 12px;font-weight:600;color:#4a6fb5;border-bottom:1px solid rgba(74,111,181,0.25);background:rgba(74,111,181,0.12)">S&eacute;rsic fit &mdash; r band, from CasJobs</td></tr>
<tr>
<td style="padding:7px 7px;padding-left:20px;border-bottom:1px solid rgba(128,128,128,0.15)"><code>rSerRadius</code></td>
<td style="padding:7px 7px;border-bottom:1px solid rgba(128,128,128,0.15)">float64</td>
<td style="padding:7px 7px;border-bottom:1px solid rgba(128,128,128,0.15)">Effective radius Re of the r-band S&eacute;rsic fit, in arcsec. Defines the sampling region.</td>
</tr>
<tr>
<td style="padding:7px 7px;padding-left:20px;border-bottom:1px solid rgba(128,128,128,0.15)"><code>rSerMag</code></td>
<td style="padding:7px 7px;border-bottom:1px solid rgba(128,128,128,0.15)">float64</td>
<td style="padding:7px 7px;border-bottom:1px solid rgba(128,128,128,0.15)">Magnitude of the r-band S&eacute;rsic fit.</td>
</tr>
<tr>
<td style="padding:7px 7px;padding-left:20px;border-bottom:1px solid rgba(128,128,128,0.15)"><code>rSerAb</code></td>
<td style="padding:7px 7px;border-bottom:1px solid rgba(128,128,128,0.15)">float64</td>
<td style="padding:7px 7px;border-bottom:1px solid rgba(128,128,128,0.15)">Axis ratio b/a of the fitted ellipse, between 0 and 1. Defines the sampling region.</td>
</tr>
<tr>
<td style="padding:7px 7px;padding-left:20px;border-bottom:1px solid rgba(128,128,128,0.15)"><code>rSerPhi</code></td>
<td style="padding:7px 7px;border-bottom:1px solid rgba(128,128,128,0.15)">float64</td>
<td style="padding:7px 7px;border-bottom:1px solid rgba(128,128,128,0.15)">Position angle of the fitted ellipse, in degrees. Defines the sampling region.</td>
</tr>
<tr>
<td style="padding:7px 7px;padding-left:20px;border-bottom:1px solid rgba(128,128,128,0.15)"><code>rSerRa</code></td>
<td style="padding:7px 7px;border-bottom:1px solid rgba(128,128,128,0.15)">float64</td>
<td style="padding:7px 7px;border-bottom:1px solid rgba(128,128,128,0.15)">Right ascension of the S&eacute;rsic fit center, in degrees.</td>
</tr>
<tr>
<td style="padding:7px 7px;padding-left:20px;border-bottom:1px solid rgba(128,128,128,0.15)"><code>rSerDec</code></td>
<td style="padding:7px 7px;border-bottom:1px solid rgba(128,128,128,0.15)">float64</td>
<td style="padding:7px 7px;border-bottom:1px solid rgba(128,128,128,0.15)">Declination of the S&eacute;rsic fit center, in degrees.</td>
</tr>
<tr><td colspan="3" style="padding:8px 12px;font-weight:600;color:#4a6fb5;border-bottom:1px solid rgba(74,111,181,0.25);background:rgba(74,111,181,0.12)">Cross-validation</td></tr>
<tr>
<td style="padding:7px 7px;padding-left:20px;border-bottom:1px solid rgba(128,128,128,0.15)"><code>fold</code></td>
<td style="padding:7px 7px;border-bottom:1px solid rgba(128,128,128,0.15)">int64</td>
<td style="padding:7px 7px;border-bottom:1px solid rgba(128,128,128,0.15)">Cross-validation fold, from 1 to 5, inherited from the source galaxy.</td>
</tr>
</tbody>
</table>
</div>

## References
[1] F&ouml;rster, F., Mu&ntilde;oz Arancibia, A. M., Reyes-Jainaga, I., et al. 2022,
*DELIGHT: Deep Learning Identification of Galaxy Hosts of Transients using
Multiresolution Images*, The Astronomical Journal, 164, 195.
[doi:10.3847/1538-3881/ac912a](https://doi.org/10.3847/1538-3881/ac912a)
```bibtex
@article{Forster_2022,
  doi = {10.3847/1538-3881/ac912a},
  url = {https://doi.org/10.3847/1538-3881/ac912a},
  year = {2022},
  month = {oct},
  publisher = {The American Astronomical Society},
  volume = {164},
  number = {5},
  pages = {195},
  author = {F\"orster, Francisco and Mu\~noz Arancibia, Alejandra M. and Reyes-Jainaga, Ignacio and Gagliano, Alexander and Britt, Dylan and Cuellar-Carrillo, Sara and Figueroa-Tapia, Felipe and Polzin, Ava and Yousef, Yara and Arredondo, Javier and Rodr\'iguez-Mancini, Diego and Correa-Orellana, Javier and Bayo, Amelia and Bauer, Franz E. and Catelan, M\'arcio and Cabrera-Vives, Guillermo and Dastidar, Raya and Est\'evez, Pablo A. and Pignata, Giuliano and Hern\'andez-Garc\'ia, Lorena and Huijse, Pablo and Reyes, Esteban and S\'anchez-S\'aez, Paula and Ram\'irez, Mauricio and Grand\'on, Daniela and Pineda-Garc\'ia, Jonathan and Chabour-Barra, Francisca and Silva-Farf\'an, Javier},
  title = {DELIGHT: Deep Learning Identification of Galaxy Hosts of Transients using Multiresolution Images},
  journal = {The Astronomical Journal},
}
```