astronomy

J2341+0018

J2341+0018 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 J2341+0018 rather than just read about it. In short: J2341+0018 also known as PKS 2338+000 and OGC 123, is a BL Lacertae object located in the constellation of Pisces. The redshift of the object is (z) 0.276 and it is the brightest cluster galaxy (BCG) of an X-ray galaxy cluster called RX J2341.1+0018.

Key takeaways

J2341+0018 belongs to astronomy; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
Connect J2341+0018 to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of J2341+0018 from memory before moving on to harder problems.

Reference excerpt

J2341+0018 also known as PKS 2338+000 and OGC 123, is a BL Lacertae object located in the constellation of Pisces. The redshift of the object is (z) 0.276 and it is the brightest cluster galaxy (BCG) of an X-ray galaxy cluster called RX J2341.1+0018.

Description J2341+0018 is an elliptical galaxy with a radio-loud active galactic nucleus (AGN) and has an R-band luminosity of 12.3 magnitude based on the R-band luminosity estimation made with Sloan Digital Sky Survey (SDSS). It is also an early-type galaxy with a total stellar mass that is estimated to be 11.58 M☉ and a total hydrogen-alpha (Hα) star formation of 55.84 M☉ per year. The optical spectrum of the galaxy shows the presence of strong emission lines positioned on top of a stellar continuum, thus ruling out the possibility of a blazar source. The lines are significantly broad, with full width at half maximum speeds of up to 1,400 kilometers per second, suggesting the line kinematics are disturbed. The g – r color offset of J2341+0018 is -0.58 magnitude. The radio source of J2341+0018 has an unresolved appearance. Its spectral energy distribution has a steep radio spectrum at high frequencies, yet also flattening less than a few hundred GHz. The spectral energy distribution of the source has a turnover frequency based on its flux density at 365 MHz. The spectral energy distribution component has parameters of 2.62 ± 0.01, -0.16 ± 0.06 and -0.15 ± 0.04 respectively based on a fit measurement with a low peak gigahertz peaked component. Further radio imaging of J2341+0018 made with Very Long Baseline Interferometry (VLBI) detected a radio core with an inverted spectrum as well as a radio jet. The core has a total flux density of 70 mJy,while the jet has a flux density of 270 mJy. Most of the radio emission is concentrated inside a component within the central radius of 120 parsecs. The jet on parsec-scales is estimated to have a position angle of 52°, while the median distance between the core and jet components is 5.4 milliarcseconds. A study published in 2022, described J2341+0018 as a weak source with detected variability of 4.5% and has a mean flux density of 98 mJy at 15 GHz.

References

External links J2341+0018 on WikiSky: DSS2, SDSS, GALEX, IRAS, Hydrogen α, X-Ray, Astrophoto, Sky Map, Articles and images

Illustrations

Worked examples

Example 1 — a first encounter with J2341+0018

Start with the simplest possible case. Write down what J2341+0018 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 J2341+0018 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 J2341+0018 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 J2341+0018

In research: J2341+0018 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 J2341+0018 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: J2341+0018 is common in secondary-school and first-year university syllabi. It links to neighbouring topics Active galaxies, BL Lacertae objects, Elliptical galaxies, so understanding it makes those chapters shorter.
In everyday life: Look for J2341+0018 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 J2341+0018 in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what J2341+0018 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 J2341+0018 out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is J2341+0018 in simple terms?

Why does J2341+0018 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 J2341+0018?

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 J2341+0018.