---
title: "J0439+1634"
url: "https://spacecatalog.org/object/uhs-j0439-1634"
release: "DR1"
licence: "CC-BY-4.0"
citation: "SpaceCatalog. J0439+1634 [catalogue entry]. Data release DR1 (2026-08-21). https://spacecatalog.org/object/uhs-j0439-1634"
---

# J0439+1634

J0439+1634 is a quasar in the constellation [Taurus](https://spacecatalog.org/constellation/taurus), 203.8 Gly from Earth. It was discovered in 2019.

The brightest quasar known in the early universe, and only because a faint [galaxy](https://spacecatalog.org/galaxies) in front of it magnifies its light about fifty times. Corrected for the lens it is an ordinary member of its population — which is the point: every other early quasar bright enough to study easily may be lensed too.

## At a glance

- **WHAT IT IS:** Quasar
- **HOW FAR:** 203.8 Gly — A luminosity distance, from its redshift — how faint it looks. The light itself left 12.5 billion years ago.
- **WHERE TO LOOK:** [Taurus](https://spacecatalog.org/constellation/taurus) — The patch of sky it sits in, as seen from Earth.

## Properties

| Quantity | Value |
| --- | --- |
| CLASS | Quasar |
| DISTANCE FROM EARTH | 203.8 Gly — by luminosity distance from a published redshift, flat ΛCDM with H0 = 70 km/s/Mpc |
| CONSTELLATION | Taurus |
| RIGHT ASCENSION (J2000) | 04h 39m 47.1s |
| DECLINATION (J2000) | +16° 34′ 16.0″ |
| DISCOVERED | 2019 |

## Catalogue data

### WHAT KIND OF THING IT IS

What the object is in itself, rather than how it happens to look from here.

| Field | Value |
| --- | --- |
| Accretion state | quasar — a thin disc near its Eddington limit |

### WHERE IT IS AND HOW IT MOVES

Position, motion across the sky and the size it covers on it. These are measurements of the object as seen from here, so every one of them depends on where here is.

| Field | Value |
| --- | --- |
| Redshift (z) | 6.5188 |

## Also known as

- Common name: J0439+1634

## Source

[SpaceCatalog curated data](https://spacecatalog.org/releases) — CC-BY-4.0

How this was made: https://spacecatalog.org/methods#source-curated

## Cite this page

SpaceCatalog. J0439+1634 \[catalogue entry\]. Data release DR1 (2026-08-21). https://spacecatalog.org/object/uhs-j0439-1634

```bibtex
@misc{spacecatalog_uhs-j0439-1634,
  author       = {{SpaceCatalog}},
  title        = {{J0439+1634}},
  howpublished = {SpaceCatalog, data release DR1 (2026-08-21)},
  year         = {2026},
  url          = {https://spacecatalog.org/object/uhs-j0439-1634},
  note         = {Catalogue entry, data release DR1 (2026-08-21). Values from SpaceCatalog curated data.}
}
```

SpaceCatalog curated data — CC-BY-4.0

The page itself, with its pictures, the sky map and the observing tools: https://spacecatalog.org/object/uhs-j0439-1634