astronomy

NGC 4941

NGC 4941 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 NGC 4941 rather than just read about it. In short: NGC 4941 is a spiral galaxy in the constellation Virgo. The galaxy lies about 45 million light years away from Earth, which means, given its apparent dimensions, that NGC 4941 is approximately 60,000 light years across.

Key takeaways

NGC 4941 belongs to astronomy; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
Connect NGC 4941 to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of NGC 4941 from memory before moving on to harder problems.

Reference excerpt

NGC 4941 is a spiral galaxy in the constellation Virgo. The galaxy lies about 45 million light years away from Earth, which means, given its apparent dimensions, that NGC 4941 is approximately 60,000 light years across. It was discovered by German-British astronomer William Herschel on April 24, 1784.

Characteristics NGC 4941 has an elliptical bulge which appears twisted. Two spiral arms emerge from the major axis of the bulge. The arms are smooth and low contrast and appear symmetric. The arms fade after about half a revolution and merge into the disk. Multiple spiral fragments are visible in the disk, along with dust lanes. The galaxy has two very low surface brightness outer arms. HII regions are visible along the arms. The galaxy has two rings, one between 37 and 73 arcseconds from the nucleus, and one outer between 81 and 120 arcseconds from the nucleus. A weak bar is visible between the two rings.

Nucleus The nucleus of NGC 4941 has been found to be active and it has been categorised as a type II Seyfert galaxy. The most accepted theory for the energy source of active galactic nuclei is the presence of an accretion disk around a supermassive black hole. The mass of the black hole in the centre of NGC 4941 is estimated to be 106.91 (8.1 million) M☉. Imaging of the [S III] emission in the narrow-line region of the nucleus by the Gemini Multi-Object Spectrograph showed there is a blueshifted element running along a small northwest radio emission indicating there is a compact outflow associated with a radio jet. The length of the outflow is estimated to be about 150 parsec. There is a redshift element at the opposite direction, indicating there is one more outflow, but without a counterpart visible in radiowaves. The radio jet is about 15 parsec long. The nucleus of NGC 4941 is a source of X-rays. The spectrum indicates it is highly absorbed. The Fe-Kα line is detectable. The X-ray emission shows variability in the timescale of months to years when comparing observations by ASCA and BeppoSAX. The spectrum shows a partially or fully absorbed component, a reflection from the accretion disk and from the circumnuclear torus, a scattered component and thermal plasma emission, maybe a result of increased star formation activity. The hard X-ray luminosity of the nucleus is estimated to be 4.5×1041 erg/s. Although the nucleus appears deficient in molecular gas, there is some CO(3-2) emission which corresponds to a molecular gas mass of 1.9–3.3 × 104 M☉. The CO nuclear emission shows two peaks in a butterfly shape.

Nearby galaxies NGC 4941 is a member of the NGC 4941 Group, along with NGC 4951. A. M. Garcia considers the galaxy a member of the NGC 4697 Group, also known as LGG 314. Other members of the group include NGC 4697, NGC 4731, NGC 4775, NGC 4951, NGC 4948, and NGC 4958. It is part of a Virgo II Groups, a chain of groups extending from the Virgo Cluster.

Gallery

References

External links

NGC 4941 on WikiSky: DSS2, SDSS, GALEX, IRAS, Hydrogen α, X-Ray, Astrophoto, Sky Map, Articles and images NGC 4941 on SIMBAD

Illustrations

Worked examples

Example 1 — a first encounter with NGC 4941

Start with the simplest possible case. Write down what NGC 4941 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 NGC 4941 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 NGC 4941 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 NGC 4941

In research: NGC 4941 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 NGC 4941 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: NGC 4941 is common in secondary-school and first-year university syllabi. It links to neighbouring topics Astronomical objects discovered in 1784, Discoveries by William Herschel, Intermediate spiral galaxies, so understanding it makes those chapters shorter.
In everyday life: Look for NGC 4941 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 NGC 4941 in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what NGC 4941 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 NGC 4941 out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is NGC 4941 in simple terms?

Why does NGC 4941 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 NGC 4941?

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 NGC 4941.