astronomy

PKS 0420−014

PKS 0420−014 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 0420−014 rather than just read about it. In short: PKS 0420−014 is a blazar located in the constellation of Eridanus. This is a high polarized quasar with a redshift of (z) 0.915, first discovered as an astronomical radio source by astronomers in 1975.

Key takeaways

PKS 0420−014 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 0420−014 to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of PKS 0420−014 from memory before moving on to harder problems.

Reference excerpt

PKS 0420−014 is a blazar located in the constellation of Eridanus. This is a high polarized quasar with a redshift of (z) 0.915, first discovered as an astronomical radio source by astronomers in 1975. The radio spectrum of this source appears to be flat, making it a flat-spectrum radio quasar (FRSQ).

Description PKS 0420−014 is found to be violently variable on the electromagnetic spectrum from long-centimeter to short-millimeter wavelengths. It is a source of gamma ray activity, showing a flux of (E>100 MeV) of (0.8±0.2)×10−6 photons cm s−2 at the time of its high state, when observed by the Large Area Telescope in January 2010. Additionally, optical flares not associated with gamma ray activity were observed in PKS 0420−014. In 1979 a flare displayed a magnitude increase of 1.3 in 5 days, which was followed by a decreasing magnitude of 1.7 in 23 days. Its flare recorded between February and March 1992, was the highest observed optical state observed during the period EGRET recorded the highest gamma ray flux density. Subsequent flares were detected in July 2012 and in October 2020, when it reached a magnitude of 15.25 on both days, after a state of quiescence. The source of PKS 0420−014 at milliarcsecond (mas) resolutions shows a symmetrical and unresolved core. This is interpreted as the case of either the jet being aligned near the line of sight or a "naked" core. At lambda observations at 7 millimeters, the source is resolved into a core and a bent jet while at kiloparsec scales, it shows a structure extending directly south out by 25" with a weak secondary component located northeast of the core. The jet of PKS 0420−014 is strongly dominated by a radio core in parsec-scales, indicating the presence of a multicomponent substructure in its core. There are two moving components in the jet's innermost part, with one of them located near the core exhibiting a slower motion and accelerating beyond 0.2 mas as soon its trajectory switches from -100° to -175°. A bright outer component located from the core, is also shown to move ballistically along -72° at a similar speed to the inner component. There are also five other jet components displaying superluminal motion at βapp ~ 2-14c, with all of them following a common curved path within the jet. It is suggested that the source for the flux density variations in PKS 0420−014 is the presence of a binary supermassive black hole system with masses of about 7 × 107 M☉ and 2.1 × 108 M☉ which have a rotation period of 150 years. The gravitational influence of this binary system likely causes the precession of its accretion disk as well as the ejection of plasma from the black hole. As the accretion disk is precessed, the magnetic field lines and relativistic beaming are both perturbed.

References

External links PKS 0420−014 on SIMBAD PKS 0420−014 on NASA/IPAC Database

Illustrations

Worked examples

Example 1 — a first encounter with PKS 0420−014

Start with the simplest possible case. Write down what PKS 0420−014 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 0420−014 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 0420−014 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 0420−014

In research: PKS 0420−014 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 0420−014 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 0420−014 is common in secondary-school and first-year university syllabi. It links to neighbouring topics Active galaxies, Astronomical objects discovered in 1975, BL Lacertae objects, so understanding it makes those chapters shorter.
In everyday life: Look for PKS 0420−014 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 0420−014 in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what PKS 0420−014 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 0420−014 out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is PKS 0420−014 in simple terms?

Why does PKS 0420−014 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 0420−014?

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 0420−014.