astronomy

NGC 1365

NGC 1365 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 1365 rather than just read about it. In short: NGC 1365, also known as the Fornax Propeller Galaxy or the Great Barred Spiral Galaxy, is a double-barred spiral galaxy about 56 million light-years away in the constellation Fornax. It was discovered by Scottish astronomer James Dunlop on 2 September 1826.

Key takeaways

NGC 1365 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 1365 to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of NGC 1365 from memory before moving on to harder problems.

Reference excerpt

NGC 1365, also known as the Fornax Propeller Galaxy or the Great Barred Spiral Galaxy, is a double-barred spiral galaxy about 56 million light-years away in the constellation Fornax. It was discovered by Scottish astronomer James Dunlop on 2 September 1826.

Characteristics NGC 1365 is a large barred spiral galaxy in the Fornax Cluster. Within the larger long bar stretching across the center of the galaxy appears to be a smaller bar that comprises the core, with an apparent size of about 50″ × 40″. This second bar is more prominent in infrared images of the central region of the galaxy, and likely arises from a combination of dynamical instabilities of stellar orbits in the region, along with gravity, density waves, and the overall rotation of the disc. The inner bar structure likely rotates as a whole more rapidly than the larger long bar, creating the diagonal shape seen in images. The spiral arms extend in a wide curve north and south from the ends of the east–west bar and form an almost ring like Z-shaped halo. Astronomers think NGC 1365's prominent bar plays a crucial role in the galaxy's evolution, drawing gas and dust into a star-forming maelstrom and ultimately feeding material into the central black hole. NGC 1365, including its two outer spiral arms, spreads over around 300,000 light-years. Different parts of the galaxy take different times to make a full rotation around the core of the galaxy, with the outer parts of the bar completing one circuit in about 350 million years. NGC 1365 and other galaxies of its type have come to more prominence in recent years with new observations indicating that the Milky Way could also be a barred spiral galaxy. Such galaxies are quite common — two thirds of spiral galaxies are barred according to recent estimates, and studying others can help astronomers understand our own galactic home.

Supernovae Four supernovae have been observed in NGC 1365:

SN 1957C (type unknown, mag. 16.5) was discovered by Howard S. Gates on 19 October 1957. SN 1983V (Type Ic, mag. 13.5) was discovered by Robert Evans on November 25 1983, and independently discovered by P. O. Lindblad and P. Grosbol on 27 November 1983. SN 2001du (Type II, mag. 14) was discovered by Robert Evans on 24 August 2001. SN 2012fr (Type Ia, mag. 14.7) was discovered by Alain Klotz on 27 October 2012.

Supermassive black hole The central supermassive black hole in the active nucleus, which has a mass of about 2 million solar masses or half the mass of the Milky Way's central black hole Sagittarius A*, rotates at close to the speed of light. These observations, announced in February 2013, were made using the X-ray telescope satellite NuSTAR.

The location of NGC 1365 in the sky As seen from earth, the location of NGC 1365 is one and a half degrees eastward of STAR 2 (Philip S. Harrington's STAR 2) which is a telescopic asterism in the shape of a triangle, composed of the stars Chi 1-2-3 Fornacis (χ 1-2-3 Fornacis).

See also NGC 1300 NGC 1097 List of NGC objects (1001–2000)

References

External links

An Elegant Galaxy in an Unusual Light — ESO press release 22 September 2010 The Great Barred Spiral Galaxy Fine Details in a Barred Galaxy — ESO press release 27 February 1999 Starry Bulges Yield Secrets to Galaxy Growth — Hubble Space Telescope press release October 6, 1999 01:00 PM (EDT) Starry bulges yield secrets to galaxy growth Lars Lindberg Christensen, ESA/Hubble news release 6 October 1999 Supermassive Black Hole Spins Super-Fast (Release No.: 2013-07 : February 27, 2013) NASA's NuSTAR Helps Solve Riddle of Black Hole Spin NuSTAR Feb 27, 2013 EXTREME X-RAY VARIABILITY AND ABSORPTION IN NGC 1365 Archived 2014-12-18 at the Wayback Machine XMM-Newton "NGC 1365". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2013-03-06. NGC 1365 at Constellation Guide

Illustrations

Worked examples

Example 1 — a first encounter with NGC 1365

Start with the simplest possible case. Write down what NGC 1365 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 1365 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 1365 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 1365

In research: NGC 1365 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 1365 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 1365 is common in secondary-school and first-year university syllabi. It links to neighbouring topics Astronomical objects discovered in 1826, Barred spiral galaxies, Discoveries by James Dunlop, so understanding it makes those chapters shorter.
In everyday life: Look for NGC 1365 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 1365 in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what NGC 1365 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 1365 out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is NGC 1365 in simple terms?

Why does NGC 1365 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 1365?

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 1365.