astronomy

ULAS J1342+0928

ULAS J1342+0928 is a astronomy topic covered in the lgStudy science library. This page brings together a partial reference excerpt, illustrations, worked examples, real-world applications and a short study plan, so you can understand ULAS J1342+0928 rather than just read about it. In short: ULAS J1342+0928 is the third-most distant known quasar detected and contains the second-most distant and oldest known supermassive black hole, at a reported redshift of z = 7.54. The ULAS J1342+0928 quasar is located in the Boötes constellation.

Key takeaways

ULAS J1342+0928 belongs to astronomy; place it in that map before memorising details.
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Reference excerpt

ULAS J1342+0928 is the third-most distant known quasar detected and contains the second-most distant and oldest known supermassive black hole, at a reported redshift of z = 7.54. The ULAS J1342+0928 quasar is located in the Boötes constellation. The related supermassive black hole is reported to be "780 million times the mass of the Sun". At its discovery, it was the most distant known quasar. In 2021 it was eclipsed by QSO J0313-1806 as the most distant quasar.

Discovery On 6 December 2017, astronomers published that they had found the quasar using data from the Wide-field Infrared Survey Explorer (WISE) combined with ground-based surveys from the United Kingdom Infrared Telescope and the DECam Legacy Survey. It was spectroscopically confirmed using data from the Magellan Telescopes at Las Campanas Observatory in Chile, as well as the Large Binocular Telescope in Arizona and the Gemini North telescope in Hawaii. The related black hole of the quasar existed when the universe was about 690 million years old (about 5 percent of its currently known age of 13.80 billion years). The quasar comes from a time known as "the epoch of reionization", when the universe emerged from its Dark Ages. Extensive amounts of dust and gas have been detected to be released from the quasar into the interstellar medium of its host galaxy.

Description ULAS J1342+0928 has a measured redshift of 7.54, which corresponds to a comoving distance of 29.36 billion light-years from Earth. When it was reported in 2017, it was the most distant quasar yet observed. The quasar emitted the light observed on Earth today less than 690 million years after the Big Bang, about 13.1 billion years ago. The quasar's luminosity is estimated at 4×1013 solar luminosities. This energy output is generated by a supermassive black hole estimated at 7.8×108 solar masses. According to lead astronomer Bañados, "This particular quasar is so bright that it will become a gold mine for follow-up studies and will be a crucial laboratory to study the early universe."

Significance The light from ULAS J1342+0928 was emitted before the end of the theoretically predicted transition of the intergalactic medium from an electrically neutral to an ionized state (the epoch of reionization). Quasars may have been an important energy source in this process, which marked the end of the cosmic Dark Ages, so observing a quasar from before the transition is of major interest to theoreticians. Because of their high ultraviolet luminosity, quasars also are some of the best sources for studying the reionization process. The discovery is also described as challenging theories of black hole formation, by having a supermassive black hole much larger than expected at such an early stage in the Universe's history, though this is not the first distant quasar to offer such a challenge.

See also List of the most distant astronomical objects List of quasars J0313–1806

References

External links Carnegie Institution for Science NASA APOD − Quasar Pictures Quasar Image Gallery/perseus

Illustrations

Worked examples

Example 1 — a first encounter with ULAS J1342+0928

Start with the simplest possible case. Write down what ULAS J1342+0928 claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In astronomy, the smallest case is usually a single object, a single equation or a single measurement. Check that every symbol or term in your sentence has a meaning in that case.

Example 2 — changing one variable

Take the situation from Example 1 and change exactly one quantity: double it, halve it, or set it to zero. Predict what should happen to ULAS J1342+0928 before you calculate. Comparing your prediction with the result is the fastest way to find out whether you understand the idea or only the words.

Example 3 — an exam-style question

Typical questions about ULAS J1342+0928 ask you to (a) state it precisely, (b) apply it to given data, and (c) explain a limitation. Practise writing all three answers in under five minutes; the third part is what separates a full-mark answer from an average one.

Applications of ULAS J1342+0928

In research: ULAS J1342+0928 appears in astronomy research whenever the underlying quantities have to be modelled precisely. Papers usually cite it as a starting assumption and then explore where it breaks down.
In technology and industry: Engineering practice reuses ULAS J1342+0928 in design rules, simulations and safety margins. Knowing the idea lets you read a specification sheet and understand why the numbers look the way they do.
In the classroom: ULAS J1342+0928 is common in secondary-school and first-year university syllabi. It links to neighbouring topics Astronomical objects discovered in 2017, Boötes, Quasars, so understanding it makes those chapters shorter.
In everyday life: Look for ULAS J1342+0928 outside the textbook — in sport, cooking, traffic, electronics or the sky above you. An example you found yourself is remembered far longer than one you were given.

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How to study ULAS J1342+0928 in 20 minutes

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Frequently asked questions

What is ULAS J1342+0928 in simple terms?

Why does ULAS J1342+0928 matter?

Because it connects several astronomy ideas at once: it gives you a definition you can apply, a quantity you can calculate, and a way to check whether a result is plausible.

How should I study ULAS J1342+0928?

Read the excerpt, restate it from memory, then work through the examples and applications listed on this page. The five-step study plan above takes about twenty minutes.

What does this page cover?

It gives you a compact reference excerpt plus original lgStudy explanations, examples, applications and study material on ULAS J1342+0928.