astronomy

PKS 2356−61

PKS 2356−61 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 PKS 2356−61 rather than just read about it. In short: PKS 2356−61 is an active Seyfert type 2 galaxy located in the Southern constellation of Tucana. The redshift of the galaxy is (z) 0.096 and it was first discovered in the Parkes Catalogue of Radio Sources survey by astronomers in 1964.

Key takeaways

PKS 2356−61 belongs to astronomy; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
Connect PKS 2356−61 to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of PKS 2356−61 from memory before moving on to harder problems.

Reference excerpt

PKS 2356−61 is an active Seyfert type 2 galaxy located in the Southern constellation of Tucana. The redshift of the galaxy is (z) 0.096 and it was first discovered in the Parkes Catalogue of Radio Sources survey by astronomers in 1964. The galaxy is also located close to the radio source axis.

Description PKS 2356−61 is classified as a giant narrow-line radio galaxy (GRG) with a Fanaroff-Riley Class Type II morphology. The host galaxy is an E3 elliptical based on a standard de Vaucouleurs law with total radius of 5.6 arcseconds. There is a possible dust lane feature present in the galaxy. Evidence also pointed it as the result of multiple galaxy mergers, given it shows an irregular arc-like feature on its northern side and shell structures both located south and towards northeast. Two more faint arc-like features are discovered northwest and southeast by 82 and 118 kiloparsecs from the center. The radio structure of PKS 2356−61 is compact. Earlier imaging at 1410 MHz, depicted it as elongated, made up of a series of multiple components closely aligning with the radio axis. Two of these components are the strongest while the polarization is spread out unevenly, mainly near the faintest known component and two southernmost components. Radio imaging made by the Australia Telescope Compact Array has discovered traces of undetected hotspots with short and bright tail features being directed to the center from the hotspots. An extension is seen connecting from the northwest radio lobe. A radio core has been found with a flux density of 0.53×1040 erg s–1. Traces of X-ray emission is found mostly around the source and the bases of the radio lobes. PKS 2356−61 shows a presence of an extended emission-line region. Based on studies, the region is divided into two separate distinctive regions, mainly a central component and a tail component. The central component is described to have a velocity width of 300–400 km s–1. while the tail component is found elongating away from the region center and has a lower velocity width between 120 and 150 km s–1. A close faint Hydrogen-alpha emitting galaxy is located 60 kiloparsecs towards north from the host galaxy.

References

External links PKS 2356-61 on SIMBAD

Illustrations

Worked examples

Example 1 — a first encounter with PKS 2356−61

Start with the simplest possible case. Write down what PKS 2356−61 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 PKS 2356−61 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 PKS 2356−61 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 PKS 2356−61

In research: PKS 2356−61 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 PKS 2356−61 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: PKS 2356−61 is common in secondary-school and first-year university syllabi. It links to neighbouring topics Active galaxies, Astronomical objects discovered in 1964, Elliptical galaxies, so understanding it makes those chapters shorter.
In everyday life: Look for PKS 2356−61 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 PKS 2356−61 in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what PKS 2356−61 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 PKS 2356−61 out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is PKS 2356−61 in simple terms?

Why does PKS 2356−61 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 PKS 2356−61?

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 PKS 2356−61.