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The galaxy atlas.

A self-supervised map of thousands of real JWST galaxies.

A SimCLR encoder was shown thousands of JWST cutouts with no labels and learned to place galaxies that look alike near each other. Here is its 2-D map (UMAP). Drag to fly, scroll to zoom; thumbnails appear as you dive in. Step the colour key left to right: the three sky regions are mixed (location doesn't drive the map), but morphology separates, and at the far right anomaly lights up the weird ones. None of these labels were seen during training. loading atlas…

colour by

loading atlas…

What you're seeing. Each point is a real JWST/NIRCam galaxy (GOODS-S, COSMOS, UDS), pulled from the DAWN JWST Archive. A ResNet-18 trained by self-supervised contrastive learning (SimCLR, NT-Xent) maps each cutout to a vector; UMAP flattens those vectors to this 2-D layout. Morphology labels from Galaxy Zoo only colour the map; the geometry is the encoder's alone. Colour by anomaly (far right) for the payoff: the known Little Red Dots appear automatically and land where the encoder flagged the unusual, with no labels.

Things to notice

Morphology, from no labels

Flip the colour from sky region to morphology: with no labels, the encoder has already sorted galaxies into smooth, featured and merger.

how it knows

It only ever saw pixels

SimCLR pulls two random crops of the same cutout together and pushes different galaxies apart, so look-alikes end up neighbours.

The Galaxy Zoo votes only colour the finished map; they never touched training.

Where barely matters

Under sky region the three deep fields stay thoroughly mixed: a disk in GOODS-S sits beside one in COSMOS.

but not nothing

A faint survey fingerprint

A classifier can still guess the field 63% of the time (±0.5% across folds, vs 41% by chance), but that's mostly survey depth and PSF, not real structure.

And the Red-Dot signal isn't a depth artefact: retrain the encoder with a whole field held out, and the anomaly enrichment on that unseen field survives, so it's about galaxies, not the survey.

The Red Dots find the heat

Colour by anomaly: 216 known Little Red Dots (a separate published catalogue laid over the atlas, not drawn from it) pile into the same corner the encoder flagged as weird, though it was never told they exist.

why they stand out

Compact and red = isolated

LRDs are compact, uncommon and genuinely red, so they sit far from everything in latent space → a high anomaly score (7.4× enriched in the top 10%; 95% CI 6.8–7.9×, p<0.0001 against a random-galaxy null). The 216 are every known Little Red Dot in these fields, a fixed set.

The encoder is point-source aware: each cutout is centred on its source and stretched against the real sky noise, so empty sky stays dark instead of becoming colour static. That sharpened the signal from ~5× to 7.4×, and it holds up even on a deep field the encoder was never trained on.

So can it find new Little Red Dots?

The honest test: rank the atlas by anomaly, take the reddest, most compact outliers that aren't in any known catalogue, and check them. The pipeline rediscovered two published LRDs on its own but turned up no genuinely new one. It's a validated method, not a discovery claim, and we'd rather say so.

the full story

Rediscovery yes, discovery no, and we can show why

The two rediscoveries (Akins+24 COSMOS-Web dots, matched to 0.14″) are the real win: the encoder flagged them with no labels, and they pass the published selection cuts: an end-to-end validation. The rest of the shortlist looked red only in quick-look photometry; measured in the full survey catalogues they come out at F277W−F444W ≈ 0, not the ≈1 of a real Red Dot.

The reason is built in: this atlas is seeded from bright, human-classified Galaxy Zoo galaxies, so it can't reach the faint population where undiscovered Red Dots hide. Catching those needs a fainter, JWST-native starting sample, the next build.

Why does the map have this shape?
The outline is the projection's, not the galaxies'. UMAP squeezes the encoder's 512-dimensional vectors down to 2-D; the overall silhouette depends on UMAP's settings and a random seed. Change them and the blob reshapes, but which galaxies sit together stays put. Read it like a subway map: adjacency is meaningful and the outline isn't; the axes have no units.

It's one connected cloud, not separate islands, because morphology is a continuum (smooth blends into featured blends into disturbed), so colour shifts gradually instead of snapping into clusters.

Dense vs sparse = common vs rare appearance. The crowded interior is the big population of small, smooth sources; the thin spikes reaching the edges are unusual cutouts (very compact, very extended, or artefacts) that the layout flings outward. Those outliers are exactly what the anomaly colour mode scores, and where the known Little Red Dots land.

Two colour caveats. The sizes of the morphology-coloured regions reflect our balanced sampling, not the true sky mix; and under sky region the colours stay intermixed, confirming the geometry follows what galaxies look like, not where they are.

Where are we looking?

These galaxies live in three deep fields chosen to look out of our own Milky Way. Spin the globe: the three fields sit near the poles of the gold galactic plane (far from its dust) and at varied distances from the cyan ecliptic (Earth's orbital plane).

drag to rotate · gold = galactic plane · cyan = ecliptic · the three coloured dots = the deep fields (same colours as the atlas "sky region" mode) · the Sun's spot is for today

Edge-on cutaway: sightlines from the Sun out of the galactic disk to the deep fields The Milky Way drawn edge-on. A sightline along the disk is blocked; sightlines to COSMOS, GOODS-S and UDS leave the disk steeply into the clear galactic caps. Milky Way disk, edge-on: dust, gas, billions of stars blocked along the disk b COSMOS · b +42° GOODS-S · b −54° UDS · b −60° the Sun (us) clear caps → distant galaxies clear caps → distant galaxies

galactic latitude b is the angle each sightline makes with the disk; bigger means a cleaner view out. (schematic, not to scale)