astronomy

MAssive Cluster Survey

MAssive Cluster Survey 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 MAssive Cluster Survey rather than just read about it. In short: The MAssive Cluster Survey (MACS) compiled and characterized a sample of very X-ray luminous (and thus, by inference, massive), distant clusters of galaxies. The sample comprises 124 spectroscopically confirmed clusters at 0.3 < z < 0.7.

Key takeaways

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

Reference excerpt

The MAssive Cluster Survey (MACS) compiled and characterized a sample of very X-ray luminous (and thus, by inference, massive), distant clusters of galaxies. The sample comprises 124 spectroscopically confirmed clusters at 0.3 < z < 0.7. Candidates were selected from the ROSAT All-Sky Survey data. Cluster candidates that are south of declination -40° cannot be observed from Mauna Kea and fit into the Southern MACS (SMACS) extension. They are also being investigated when facilities are available.

History One of the galaxy clusters, MACS J0647+7015 was found to have gravitationally lensed the most distant galaxy (MACS0647-JD) then ever imaged, in 2012, by CLASH. The first statistical study of X-ray cavities in distant clusters of galaxies was performed by analyzing the Chandra X-ray observations of MACS. Out of 76 clusters representing a sample of the most luminous X-ray clusters, observers found 13 cut and clear cavities and 7 possible cavities. A new radio halo, as well as a relic applicant, were found in MACS, with the help of the Giant Meterwave Radio Telescope and the Karoo Array Telescope-7. The discovered radio halo has a largest linear scale of about 0.9Mpc. X-ray chosen clusters are almost free of projection effects because they are composed of intrinsically massive, gravitationally collapsed systems.

MACS team The MACS team consists of:

Harald Ebeling, University of Hawaii, USA Alastair Edge, University of Durham, UK J. Patrick Henry, University of Hawaii, USA

Survey notation Objects are labelled as JHHMM.m+DDMM where HHMM+DDMM are the coordinates in the J2000 system. Here H, D, and M refer to hours, degrees, and minutes, respectively, and m refers to tenths of minutes of time.

HH Hours of right ascension MM.m Minutes of right ascension or declination DD.d Degrees in declination

Southern MAssive Cluster Survey

The Southern MAssive Cluster Survey (SMACS) involved the Hubble Space Telescope.

Notable surveyed objects

References

External links

http://mnras.oxfordjournals.org/content/407/1/83.short http://mnras.oxfordjournals.org/content/421/2/1360.short http://mnras.oxfordjournals.org/content/458/2/1803.abstract

Worked examples

Example 1 — a first encounter with MAssive Cluster Survey

Start with the simplest possible case. Write down what MAssive Cluster Survey 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 MAssive Cluster Survey 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 MAssive Cluster Survey 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 MAssive Cluster Survey

In research: MAssive Cluster Survey 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 MAssive Cluster Survey 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: MAssive Cluster Survey is common in secondary-school and first-year university syllabi. It links to neighbouring topics Astronomical surveys, so understanding it makes those chapters shorter.
In everyday life: Look for MAssive Cluster Survey 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 MAssive Cluster Survey in 20 minutes

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

Frequently asked questions

What is MAssive Cluster Survey in simple terms?

Why does MAssive Cluster Survey 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 MAssive Cluster Survey?

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 MAssive Cluster Survey.