astronomy

MRC 0316−257

MRC 0316−257 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 MRC 0316−257 rather than just read about it. In short: MRC 0316−257 is a radio galaxy located in the constellation Fornax. Its redshift is 3.13, making the object located roughly 11 billion light-years from Earth.

Key takeaways

MRC 0316−257 belongs to astronomy; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
Connect MRC 0316−257 to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of MRC 0316−257 from memory before moving on to harder problems.

Reference excerpt

MRC 0316−257 is a radio galaxy located in the constellation Fornax. Its redshift is 3.13, making the object located roughly 11 billion light-years from Earth.

Characteristics MRC 0316−257 is classified as a high redshift radio galaxy. It is found to be hosted inside a massive star-forming galaxy containing large reservoirs of gas and interstellar dust. Such host galaxies like MRC 0316−257 are believed to be progenitors of massive elliptical galaxies that are present in the local universe, given most powerful radio galaxies are hosted in ellipticals that are considered large. Its 1.5-Jy radio source was listed in the 408-MHz Molonglo Reference Catalogue which was optically identified with a galaxy at z= 3.13 with a typical radio luminosity and radio loudness of L5 = 1043 - 1044 ergs −1 and log R = 3–4.

MRC 0316−257 protocluster MRC 0316−257 is situated in the center of a massive protoclusters. The cluster has a larger size compared than 3.3x3.3 Mpc^2, which its mass structure is estimated to be > 3-6x10^14 M_sun. This makes it a progenitor of the cluster of galaxies similar to the Virgo cluster. Two Lyα emitting companions located at z = 3.1378 +/- 0.0028 and z = 3.1351 +/- 0.0028, are found in the MRC 0316−257 protocluster according to research conducted by Le Fevre et al. (1996). The first galaxy is 0.3 h ^{-1}50 Mpc from MRC 0316−257, which is then resolved with an intrinsic size of 11.6 +/- 1.1 h ^{-1}50 kpc, and a Ly alpha in emission with rest WLy alpha = 55 +/- 14 A. The galaxy has an extremely blue V - I color indicating it as a protogalaxy in the midst of forming the first stars in a low-dust medium. The second is at least 1.3 h ^{-1}50 Mpc. The galaxy is marginally resolved, which in addition to Ly alpha in emission, there is C IV in emission with its broad component indicating the contribution from the active galactic nucleus. The protocluster has a comoving density. These galaxies have V < 23.8 and Ly alpha flux greater than 10-16 ergs cm-2 s-1 within the vicinity of MRC 0316−257. They have ~2.5 x 10-3 h 350 Mpc-3, making them significantly higher than the expected background density of field galaxies, suggesting as a rich cluster. Through spectroscopy of 40 candidate emitters, 33 emission-line galaxies are discovered. 31 are Ly-alpha emitters with similar redshifts of MRC 0316−257, while the remaining two turned out to be [OII] emitters, with widths between the range of 120–800 km/s, with a median of 260 km/s. They are asymmetric, with apparent absorption troughs blueward of the profile peaks, indicative of absorption along the line of sight of an HI mass of at least 2x10^2 - 5x10^4 M_sun and are found to be faint, blue and small and consistent with young star forming galaxies considered as dust free. The volume density of Ly-alpha emitting galaxies in the field around MRC 0316−257 have a factor of 3.3+0.5-0.4. This are larger compared with the density of field Ly-alpha emitters at that redshift with a velocity distribution of 1510 km/s, smaller than the width of the narrow-band filter (FWHM ~ 3500 km/s). The velocity distribution is at the peak of 200 km/s, which is within the redshift, thus confirming Ly-alpha emitter galaxies as members of a protocluster at z~3.13.

References

Illustrations

Worked examples

Example 1 — a first encounter with MRC 0316−257

Start with the simplest possible case. Write down what MRC 0316−257 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 MRC 0316−257 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 MRC 0316−257 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 MRC 0316−257

In research: MRC 0316−257 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 MRC 0316−257 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: MRC 0316−257 is common in secondary-school and first-year university syllabi. It links to neighbouring topics Active galaxies, Fornax, Principal Galaxies Catalogue objects, so understanding it makes those chapters shorter.
In everyday life: Look for MRC 0316−257 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 MRC 0316−257 in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what MRC 0316−257 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 MRC 0316−257 out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is MRC 0316−257 in simple terms?

MRC 0316−257 is a radio galaxy located in the constellation Fornax. Its redshift is 3.13, making the object located roughly 11 billion light-years from Earth.

Why does MRC 0316−257 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 MRC 0316−257?

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 MRC 0316−257.