---
title: "ULAS J1120+0641"
url: "https://spacecatalog.org/object/ulas-j1120-0641"
release: "DR1"
licence: "CC-BY-4.0"
citation: "SpaceCatalog. ULAS J1120+0641 [catalogue entry]. Data release DR1 (2026-08-21). https://spacecatalog.org/object/ulas-j1120-0641"
---

# ULAS J1120+0641

ULAS J1120+0641 is a quasar in the constellation [Leo](https://spacecatalog.org/constellation/leo), 224.4 Gly from Earth. Its mass is 2×10⁹ M☉. It was discovered in 2011.

The first quasar found beyond a redshift of seven. Its spectrum gave the first direct evidence that a large fraction of the hydrogen in the universe was still neutral 800 million years after the Big Bang.

## At a glance

- **WHAT IT IS:** Quasar
- **HOW FAR:** 224.4 Gly — A luminosity distance, from its redshift — how faint it looks. The light itself left 12.6 billion years ago.
- **WHERE TO LOOK:** [Leo](https://spacecatalog.org/constellation/leo) — The patch of sky it sits in, as seen from Earth.

## Properties

| Quantity | Value |
| --- | --- |
| CLASS | Quasar |
| MASS | 2×10⁹ M☉ |
| DISTANCE FROM EARTH | 224.4 Gly — by luminosity distance from a published redshift, flat ΛCDM with H0 = 70 km/s/Mpc |
| CONSTELLATION | Leo |
| RIGHT ASCENSION (J2000) | 11h 20m 01.5s |
| DECLINATION (J2000) | +06° 41′ 23.8″ |
| DISCOVERED | 2011 |

## 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 |
| Mass | 2×10⁹ M☉ |

### 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) | 7.0851 |

## Also known as

- Common name: ULAS J1120+0641

## 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. ULAS J1120+0641 \[catalogue entry\]. Data release DR1 (2026-08-21). https://spacecatalog.org/object/ulas-j1120-0641

```bibtex
@misc{spacecatalog_ulas-j1120-0641,
  author       = {{SpaceCatalog}},
  title        = {{ULAS J1120+0641}},
  howpublished = {SpaceCatalog, data release DR1 (2026-08-21)},
  year         = {2026},
  url          = {https://spacecatalog.org/object/ulas-j1120-0641},
  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/ulas-j1120-0641