astronomy

IC 1459

IC 1459 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 IC 1459 rather than just read about it. In short: IC 1459 (also catalogued as IC 5265) is an elliptical galaxy located in the constellation Grus. It is located at a distance of circa 85 million light-years from Earth, which, given its apparent dimensions, means that IC 1459 is about 130,000 light-years across.

Key takeaways

IC 1459 belongs to astronomy; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
Connect IC 1459 to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of IC 1459 from memory before moving on to harder problems.

Reference excerpt

IC 1459 (also catalogued as IC 5265) is an elliptical galaxy located in the constellation Grus. It is located at a distance of circa 85 million light-years from Earth, which, given its apparent dimensions, means that IC 1459 is about 130,000 light-years across. It was discovered by Edward Emerson Barnard in 1892.

Characteristics IC 1459 is a giant elliptical galaxy. In its core has been observed a fast counter-rotating stellar component, with an estimated total mass of 3×109 M☉. The stars of this component have circular orbits on a flat disk with a radius of less than two arcseconds. It has been suggested that the stars of the counterrotating disk are of external origin, either by the accretion of a stellar satellite or of a dense molecular cloud from which the stars were created. The galaxy also features multiple shells and disturbed isophotes, which indicate that it has accreted material, probably by the merger of smaller galaxies with the elliptical galaxy. Enhanced photography revealed the presence of a diffuse spiral pattern at the outer regions of IC 1459. It has been suggested that a merger started a starburst event in IC 1459. The total duration of this event has not been well constrained, but it is estimated it lasted less than 80 million years. Young stars make up approximately 3% of the total stellar population of the galaxy. They have an average age of 400 million years. Metallicity has been found to decrease as the radial distance from the center increases. The nucleus of IC 1459 is active and has been characterised as a LINER based on its optical spectrum. The most accepted theory for the power source of active galactic nuclei is the presence of an accretion disk around a supermassive black hole. In the centre of IC 1459 lies a supermassive black hole with an estimated mass (2.6±1.0)×109 M☉ based on stellar velocities. Estimates of the mass of the black hole based on gas kinematics are lower, from (1-4) × 108 to 109 M☉, although the presence of non-gravitational forces acting on the circumnuclear gas renders them less accurate. The disturbed kinematics of the circumnuclear gas may be caused by an outflow. In the circumnuclear region there is also dust with irregular distribution, indicating nonequilibrium motions. The galaxy is characterised as low-power radio loud, with gigahertz-peaked spectrum, and has two symmetrical radio jets. In a 3.5 year observation period, the galaxy showed little variability. The galaxy also has weak X-ray emission. The nucleus appears unabsorbed in lower energy X-ray, with X-ray luminosity 7.9×1040 ergs s-1, while the Fe-Kα fluorescence line, is not strong. The infrared emission of the nucleus is also less than the one expected by an AGN hidden by a dust torus. This indicates that the AGN is seen unobstructed. The galaxy possess an X-ray halo, whose modelling indicated the presence of dark matter at a distance larger than 3 effective radii. In images by the Hubble Space Telescope, 199 globular clusters were recognised, with an indication of a decrease of their number near the core and statistically non-significant evidence of dimodial color distribution.

Nearby galaxies

IC 1459 is the brightest galaxy in a galaxy group known as the IC 1459 group. It is a loose group centred at IC 1459 with a large number of spiral galaxies. Other members include NGC 7418, NGC 7418A, NGC 7421, IC 5264, IC 5269, IC 5269B, IC 5270, and IC 5273. IC 5264 lies 6.5 arcminutes south of IC 1459. This group, along with the NGC 7582 group form the Grus cloud, a region of elevated galaxy density. The Grus cloud, along with the nearby Pavo-Indus cloud, lies between the Local Supercluster and Pavo–Indus Supercluster. The group features both diffuse X-ray emission from the intergalactic medium and HI emission. Based on the presence of both it has been suggested that the group is in its early stages of assembling from different subgroups. Three HI clouds have been found to be associated with the group, two located near IC 5270 and one near NGC 7418. These HI clouds are believed to have formed from gas stripped from the galaxies as a result of interactions.

Gallery

See also NGC 1052 - a similar elliptical galaxy

References

External links IC 1459 on WikiSky: DSS2, SDSS, GALEX, IRAS, Hydrogen α, X-Ray, Astrophoto, Sky Map, Articles and images IC 1459 on SIMBAD

Illustrations

Worked examples

Example 1 — a first encounter with IC 1459

Start with the simplest possible case. Write down what IC 1459 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 IC 1459 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 IC 1459 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 IC 1459

In research: IC 1459 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 IC 1459 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: IC 1459 is common in secondary-school and first-year university syllabi. It links to neighbouring topics Astronomical objects discovered in 1892, Discoveries by Edward Emerson Barnard, Elliptical galaxies, so understanding it makes those chapters shorter.
In everyday life: Look for IC 1459 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 IC 1459 in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what IC 1459 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 IC 1459 out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is IC 1459 in simple terms?

Why does IC 1459 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 IC 1459?

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 IC 1459.