astronomy

UGC 6541

UGC 6541 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 UGC 6541 rather than just read about it. In short: UGC 6541 (also known as Mrk 178) is a blue compact dwarf galaxy in the constellation of Ursa Major. Its velocity with respect to the cosmic microwave background is 455±14 km/s, which is too small to use to obtain a distance using Hubble's law.

Key takeaways

UGC 6541 belongs to astronomy; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
Connect UGC 6541 to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of UGC 6541 from memory before moving on to harder problems.

Reference excerpt

UGC 6541 (also known as Mrk 178) is a blue compact dwarf galaxy in the constellation of Ursa Major. Its velocity with respect to the cosmic microwave background is 455±14 km/s, which is too small to use to obtain a distance using Hubble's law. However, 10 non-redshift measurements give a mean distance of 15.15 ± 2.10 Mly (4.644 ± 0.644 Mpc). The first known reference to this galaxy comes from Erik Holmberg's A Study of Double and Multiple Galaxies Together with Inquiries into some General Metagalactic Problems, published in 1937, where UGC 6541 and UGC 6538 are listed together as Holm 263. However, since UGC 6538 is about 10 times further away, at a distance of 158.3 ± 11.1 Mly (48.55 ± 3.41 Mpc), the alignment is purely optical.

UGC 6541 has a possible active galactic nucleus, i.e. it has a compact region at the center of a galaxy that emits a significant amount of energy across the electromagnetic spectrum, with characteristics indicating that this luminosity is not produced by the stars. UGC 6541 is a galaxy whose nucleus shines brightly in the ultraviolet and is listed in the Markarian catalogue as Mrk 178. The stellar and gas components of UGC 6541 have been extensively studied. An integrated H I intensity map shows a broken ring-like structure. Other integrated H I intensity maps show that this galaxy has a highly irregular shape to its gaseous disk. A detailed study of the Wolf-Rayet population revealed a large number of Wolf-Rayet stars in its brightest stellar component. The stellar population has been studied in detail, indicating that this galaxy had a higher star formation rate 500 million years ago compared to its current rate, and that this galaxy has an old underlying stellar population.

References

External links Media related to UGC 6541 at Wikimedia Commons UGC 6541 on WikiSky: DSS2, SDSS, GALEX, IRAS, Hydrogen α, X-Ray, Astrophoto, Sky Map, Articles and images

Illustrations

Worked examples

Example 1 — a first encounter with UGC 6541

Start with the simplest possible case. Write down what UGC 6541 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 UGC 6541 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 UGC 6541 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 UGC 6541

In research: UGC 6541 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 UGC 6541 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: UGC 6541 is common in secondary-school and first-year university syllabi. It links to neighbouring topics Astronomical objects discovered in 1937, Dwarf galaxies, MCG objects, so understanding it makes those chapters shorter.
In everyday life: Look for UGC 6541 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 UGC 6541 in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what UGC 6541 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 UGC 6541 out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is UGC 6541 in simple terms?

Why does UGC 6541 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 UGC 6541?

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 UGC 6541.