astronomy

List of quasars

List of quasars 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 List of quasars rather than just read about it. In short: This article contains lists of quasars. More than a million quasars have been observed, so any list on Wikipedia is necessarily a selection of them.

Key takeaways

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

Reference excerpt

This article contains lists of quasars. More than a million quasars have been observed, so any list on Wikipedia is necessarily a selection of them. Proper naming of quasars is by Catalogue Entry, Qxxxx±yy using B1950 coordinates, or QSO Jxxxx±yyyy using J2000 coordinates. They may also use the prefix QSR. There are currently no quasars that are visible to the naked eye.

List of quasars This is a list of exceptional quasars for characteristics otherwise not separately listed

List of named quasars This is a list of quasars, with a common name, instead of a designation from a survey, catalogue or list.

List of multiply imaged quasars This is a list of quasars that as a result of gravitational lensing appear as multiple images on Earth.

List of visual quasar associations This is a list of double quasars, triple quasars, and the like, where quasars are close together in line-of-sight, but not physically related.

List of physical quasar groups This is a list of binary quasars, trinary quasars, and the like, where quasars are physically close to each other.

Large Quasar Groups

Large quasar groups (LQGs) are bound to a filament of mass, and not directly bound to each other.

List of quasars with apparent superluminal jet motion This is a list of quasars with jets that appear to be superluminal due to relativistic effects and line-of-sight orientation. Such quasars are sometimes referred to as superluminal quasars.

Quasars that have a recessional velocity greater than the speed of light (c) are very common. Any quasar with z > 1 is receding faster than c, while z exactly equal to 1 indicates recession at the speed of light. Early attempts to explain superluminal quasars resulted in convoluted explanations with a limit of z = 2.326, or in the extreme z < 2.4. The majority of quasars lie between z = 2 and z = 5.

Firsts

Extremes

First quasars found

Most distant quasars

In 1964 a quasar became the most distant object in the universe for the first time. Quasars would remain the most distant objects in the universe until 1997, when a pair of non-quasar galaxies would take the title (galaxies CL 1358+62 G1 & CL 1358+62 G2 lensed by galaxy cluster CL 1358+62). In cosmic scales distance is usually indicated by redshift (denoted by z) which is a measure of recessional velocity and inferred distance due to cosmological expansion.

Most powerful quasars

See also List of microquasars Lists of astronomical objects List of galaxies List of black holes

References

External links Interactive interface into the catalog of Quasars from the Sloane Digital Sky Survey Catalogue of Bright Quasars and BL Lacertae Objects Kitt Peak Quasar List (1975) VII/11 Revised and Updated Catalog of Quasi-stellar Objects (1993) VII/158

Worked examples

Example 1 — a first encounter with List of quasars

Start with the simplest possible case. Write down what List of quasars 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 List of quasars 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 List of quasars 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 List of quasars

In research: List of quasars 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 List of quasars 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: List of quasars is common in secondary-school and first-year university syllabi. It links to neighbouring topics Lists of galaxies, Quasars, so understanding it makes those chapters shorter.
In everyday life: Look for List of quasars 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 List of quasars in 20 minutes

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

Frequently asked questions

What is List of quasars in simple terms?

This article contains lists of quasars. More than a million quasars have been observed, so any list on Wikipedia is necessarily a selection of them.

Why does List of quasars 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 List of quasars?

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 List of quasars.