astronomy

M60-UCD1

M60-UCD1 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 M60-UCD1 rather than just read about it. In short: M60-UCD1 is an ultracompact dwarf galaxy. It is 49 million light years from Earth, close to Messier 60 (M60, NGC 4649) in the Virgo Cluster.

Key takeaways

M60-UCD1 belongs to astronomy; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
Connect M60-UCD1 to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of M60-UCD1 from memory before moving on to harder problems.

Reference excerpt

M60-UCD1 is an ultracompact dwarf galaxy. It is 49 million light years from Earth, close to Messier 60 (M60, NGC 4649) in the Virgo Cluster. Half of its stellar mass is in the central sphere 160 light years in diameter.

Characteristics

M60-UCD1's dynamical mass is 200±30 million solar masses (M☉). Colours and lack of colour gradients indicate a uniform stellar population about 14.5±0.5 billion years old (indistinguishable from the age of the Universe). Their metallicity is similar to that of the Sun. The orbital velocity dispersion of the innermost stars exceeds 100 km/s, due to the gravity of a dense mass concentration. The galactic nucleus contains a bright and variable X-ray source, presumably a supermassive black hole with a mass of 20 million M☉ (10% of the dynamical mass of the entire galaxy). With this proportion of the mass of the black hole to that of the whole galaxy, it is one of the most black hole dominated galaxies known. M60-UCD1 is believed to be the stripped core of a much more massive galaxy, whose mass was stripped in an encounter with M60 some 10 billion years ago. It may yet be absorbed completely by M60, its central black hole merging with M60's as well. The galaxy may have once had some 10 billion stars. As of 2013, it is possibly the densest known galaxy with over one hundred stars per cubic light-year. As of 2014, it is the smallest and least massive galaxy known to host a central black hole. It was previously known as the most massive ultracompact dwarf galaxy known.

See also M85-HCC1 – densest galaxy known, as of 2015.

References

Further reading Seth, Anil; van den Bosch, Remco; Mieske, Steffen; Baumgardt, Holger; den Brok, Mark; Strader, Jay; Neumayer, Nadine; Chilingarian, Igor; Hilker, Michael; McDermid, Richard; Brodie, Jean; Frank, Matthias; Walsh, Jonelle L.; "A Supermassive Black Hole in an Ultracompact Dwarf Galaxy", Nature, 513, pages 398–400, 18 September 2014; doi:10.1038/nature13762; arXiv:1409.4769; Bibcode:2014arXiv1409.4769S

External links Chandra X-Ray Observatory, "NASA's Hubble and Chandra Find Evidence for Densest Nearby Galaxy", NASA, 24 September 2013 ScienceDaily, "Evidence for Densest Nearby Galaxy", 24 September 2013 ScienceDaily, "Astronomers Discover Densest Galaxy Ever", 24 September 2013 NASA Astronomy Picture of the Day: The Densest Galaxy (October 4, 2013)

Illustrations

Worked examples

Example 1 — a first encounter with M60-UCD1

Start with the simplest possible case. Write down what M60-UCD1 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 M60-UCD1 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 M60-UCD1 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 M60-UCD1

In research: M60-UCD1 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 M60-UCD1 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: M60-UCD1 is common in secondary-school and first-year university syllabi. It links to neighbouring topics Astronomical objects discovered in 2013, Dwarf galaxies, Virgo (constellation), so understanding it makes those chapters shorter.
In everyday life: Look for M60-UCD1 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 M60-UCD1 in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what M60-UCD1 means in your own words.
Compare your version with the excerpt and mark what you missed.
Work through the three examples above with pen and paper.
Explain M60-UCD1 out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is M60-UCD1 in simple terms?

M60-UCD1 is an ultracompact dwarf galaxy. It is 49 million light years from Earth, close to Messier 60 (M60, NGC 4649) in the Virgo Cluster.

Why does M60-UCD1 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 M60-UCD1?

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 M60-UCD1.