astronomy

IC 1101

IC 1101 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 1101 rather than just read about it. In short: IC 1101 is a class S0 supergiant (cD) lenticular galaxy at the center of the Abell 2029 galaxy cluster. It has an isophotal diameter at about 123.65 to 169.61 kiloparsecs (400,000 to 550,000 light-years).

Key takeaways

IC 1101 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 1101 to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of IC 1101 from memory before moving on to harder problems.

Reference excerpt

IC 1101 is a class S0 supergiant (cD) lenticular galaxy at the center of the Abell 2029 galaxy cluster. It has an isophotal diameter at about 123.65 to 169.61 kiloparsecs (400,000 to 550,000 light-years). It possesses a diffuse core, which is the largest core of any galaxy known to date, and contains a supermassive black hole, one of the largest discovered. IC 1101 is located at 354.0 megaparsecs (1.15 billion light-years) from Earth. It was discovered on 19 June 1790, by the German-British astronomer William Herschel.

Observation history IC 1101 was catalogued in the Index Catalogue of galaxies in the late 1800s to the early 1900s, which is where the galaxy got its most-used designation. In a 1964 study of galaxies accompanied by radio sources, IC 1101 was listed as being among the diffuse elliptical galaxies chosen for the study. The study noted that IC 1101 had not been considered as a radio source, but radio emissions similar to galaxies with such emissions were detected. Almost a decade and a half later, in 1978, astronomer Alan Dressler analyzed 12 very rich clusters of galaxies, among them Abell 2029, where IC 1101 is located. The following year, he released a paper dedicated solely to IC 1101 and its related dynamics and properties, revealing a rising velocity dispersion profile. After this, he would publish a paper overviewing his recent studies on the cluster and the galaxy. During 1985, a team of astronomers obtained the spectra of the gas inside several galaxy clusters known to be luminous at X-ray wavelengths, including Abell 2029. Soon after, an investigation into the dynamics of IC 1101 and the galaxies within a few hundred kiloparsecs of it was conducted. The centers of galaxy clusters are considered to be among the best laboratories for the study of galaxy and cluster evolution, and so during the late 1980s to early 1990s, numerous papers were released, surveying many brightest cluster galaxies. Among them was IC 1101. R-band (red light) luminosity profiles were soon obtained for IC 1101, revealing a very vast halo of light that could be traced out for more than several hundred kiloparsecs from the galaxy's center. In 2002, an analysis of Chandra X-ray surveys of the cluster was performed. In 2011, a survey of over 430 brightest cluster galaxies was conducted, among them IC 1101. In 2017, a redshift survey of the cluster was conducted, allowing a list of velocity dispersions to be created. This constrains the dynamics of the cluster. That same year, an analysis of the galaxy's inner regions using Hubble Space Telescope images found a huge yet diffuse galactic core, accompanied with mass estimates of the central supermassive black hole. During 2019–2020, 170 local galaxy clusters were surveyed for a study of brightest cluster galaxies, their structures and the intracluster light around them.

Characteristics

Morphology

The galaxy is classified as a supergiant elliptical (E) to lenticular (S0) and is the brightest galaxy in A2029 (hence its other designation A2029-BCG; BCG meaning brightest cluster galaxy). The galaxy's morphological type is debated due to it possibly being shaped like a flat disc but only visible from Earth at its broadest dimensions. A morphology of S0- (Hubble stage −2; see Hubble stage for details) has been given by the Third Reference Catalogue of Bright Galaxies (RC3) in 1991.

… excerpt ends here. Continue reading the full article.

Illustrations

IC 1101: IC 1101 imaged by the 9th data release of the Legacy survey. — IC 1101 imaged by the 9th data release of the Legacy survey.

Worked examples

Example 1 — a first encounter with IC 1101

Start with the simplest possible case. Write down what IC 1101 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 1101 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 1101 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 1101

In research: IC 1101 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 1101 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 1101 is common in secondary-school and first-year university syllabi. It links to neighbouring topics Astronomical objects discovered in 1790, Discoveries by William Herschel, Elliptical galaxies, so understanding it makes those chapters shorter.
In everyday life: Look for IC 1101 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 1101 in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what IC 1101 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 1101 out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is IC 1101 in simple terms?

Why does IC 1101 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 1101?

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 1101.