astronomy

NGC 4194

NGC 4194 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 4194 rather than just read about it. In short: NGC 4194, the Medusa merger, is a galaxy merger in the constellation Ursa Major about 128 million light-years (39.1 Mpc) away. It was discovered on April 2, 1791 by German-British astronomer William Herschel.

Key takeaways

NGC 4194 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 4194 to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of NGC 4194 from memory before moving on to harder problems.

Reference excerpt

NGC 4194, the Medusa merger, is a galaxy merger in the constellation Ursa Major about 128 million light-years (39.1 Mpc) away. It was discovered on April 2, 1791 by German-British astronomer William Herschel. Due to its disturbed appearance, it is object 160 in Halton Arp's 1966 Atlas of Peculiar Galaxies.

The morphological classification of NGC 4194 is Imeger, indicating an irregular form. This galaxy consists of a brighter central region spanning an angular size 9″ across, with an accompanying system of loops and arcs. Additional material is thinly spread out to a radius of 75″ from the central region. There is a tidal tail and regions undergoing high levels of star formation, making this a starburst galaxy. It is a source for strong infrared and radio emission. These features indicate NGC 4194 is a late-stage galaxy merger. A region of extreme star formation 500 ly (150 pc) across exists in the center of the Eye of Medusa, the central gas-rich region. Within 1.2 kpc (3.9 kly) of the dynamic center of NGC 4194, star formation is occurring at a rate of 8 M☉·yr−1. The star forming regions in this volume range from 5 to 9 million years in age, with the youngest occurring in areas of the highest star formation rate. As of 2014, no galactic nucleus has been detected based on radio emissions, nor have the respective nuclei of the merger galaxies. However, X-ray emission from a black hole in the tidal tail was detected by Chandra in 2009.

References

Further reading König, S.; et al. (July 2018). "Major impact from a minor merger. The extraordinary hot molecular gas flow in the Eye of the NGC 4194 Medusa galaxy". Astronomy & Astrophysics. 615. id. A122. arXiv:1712.04030. Bibcode:2018A&A...615A.122K. doi:10.1051/0004-6361/201732436.{{cite journal}}: CS1 maint: multiple names: authors list (link) Aalto, S.; et al. (November 2010). "13CO 1-0 imaging of the Medusa merger, NGC 4194. Large scale variations in molecular cloud properties". Astronomy and Astrophysics. 522. id.A59. arXiv:1008.2095. Bibcode:2010A&A...522A..59A. doi:10.1051/0004-6361/200913511. Kaaret, Philip; Alonso-Herrero, Almudena (August 2008). "X-Ray Sources in the Star-Forming Galaxies NGC 4194 and NGC 7541". The Astrophysical Journal. 682 (2): 1020–1028. arXiv:0805.0683. Bibcode:2008ApJ...682.1020K. doi:10.1086/589764.

External links

NGC 4194 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 NGC 4194

Start with the simplest possible case. Write down what NGC 4194 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 4194 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 4194 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 4194

In research: NGC 4194 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 4194 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 4194 is common in secondary-school and first-year university syllabi. It links to neighbouring topics Arp objects, Galaxy mergers, Luminous infrared galaxies, so understanding it makes those chapters shorter.
In everyday life: Look for NGC 4194 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 4194 in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what NGC 4194 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 4194 out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is NGC 4194 in simple terms?

Why does NGC 4194 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 4194?

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 4194.