astronomy

PKS 1413+135

PKS 1413+135 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 1413+135 rather than just read about it. In short: PKS 1413+135 is a BL Lacertae object located in the constellation of Boötes. The redshift of the object is (z) 0.246 and it was first discovered by a group of astronomers in April 1991 who found it was hosted by a disc galaxy, with later studies confirming it to be a spiral galaxy, making this exceptionally rare for any BL Lac host galaxies.

Key takeaways

PKS 1413+135 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 1413+135 to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of PKS 1413+135 from memory before moving on to harder problems.

Reference excerpt

PKS 1413+135 is a BL Lacertae object located in the constellation of Boötes. The redshift of the object is (z) 0.246 and it was first discovered by a group of astronomers in April 1991 who found it was hosted by a disc galaxy, with later studies confirming it to be a spiral galaxy, making this exceptionally rare for any BL Lac host galaxies. It also contains a radio spectrum that appears as mainly flat, similar to most blazars.

Description PKS 1413+135 is categorized as an edge-on spiral galaxy of Sa morphology based on Hubble Space Telescope (HST) imaging, with a long dust lane penetrating through the middle section with a central bulge feature. Further imaging also found the nuclear regions of the galaxy are mainly peanut-shaped with the central bar feature that extends by 0.5 arcseconds in perpendicular direction as the dust lane. The central nucleus of the galaxy has a reddened appearance. The source of PKS 1413+135 is relatively compact, with a highly inverted radio core and traces of radio emission at the same position of it and also towards the northwest. There is a lack of any kiloparsec-scale extended structures based on radio imaging made by the Very Large Array (VLA). Radio imaging made with the Very Long Baseline Array (VLBA) at 15 GHz frequencies has found there is a radio jet present, going westwards by three milliarcseconds before bending. There is also a counterjet feature located at the position angle that is similar to the minilobe feature that is located east and also by 180° where the jet first emerged from. A slight extension is found at 43 GHz frequencies. VLBA imaging also suggested that PKS 1413+135 is also a young source, with a complex morphology that is similar to those sources that have compact symmetrical object (CSO) morphology. Molecular absorption clouds have been discovered towards the galaxy. Studies have also classified PKS 1413+135 as a blazar. It is noted to be highly variable, displaying extreme gamma-ray activity on 29 August 2019, with its average daily flux reaching around 4.8 ± 1.5 × 10−7 photons cm−2 s−1. On 13 January 2022, a gamma ray flare was shown to be emitted from the galaxy with the daily average flux of 2.2 ± 0.7 × 10−7 photons cm−2 s−1. More gamma-ray activity has been reported in 2023 and 2025 respectively.

References

External links PKS 1413+135 on SIMBAD

Illustrations

Worked examples

Example 1 — a first encounter with PKS 1413+135

Start with the simplest possible case. Write down what PKS 1413+135 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 1413+135 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 1413+135 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 1413+135

In research: PKS 1413+135 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 1413+135 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 1413+135 is common in secondary-school and first-year university syllabi. It links to neighbouring topics Active galaxies, BL Lacertae objects, Blazars, so understanding it makes those chapters shorter.
In everyday life: Look for PKS 1413+135 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 1413+135 in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what PKS 1413+135 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 1413+135 out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is PKS 1413+135 in simple terms?

Why does PKS 1413+135 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 1413+135?

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 1413+135.