astronomy

PHL 1222

PHL 1222 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 PHL 1222 rather than just read about it. In short: PHL 1222 also known as Q0151+048 or UM 144, is a radio-quiet binary quasar located in the constellation of Pisces. The quasar has a redshift of (z) 1.91 and was first discovered in January 1990 by astronomers Georges Meylan, Peter Shaver and Stanislav Djorgovski.

Key takeaways

PHL 1222 belongs to astronomy; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
Connect PHL 1222 to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of PHL 1222 from memory before moving on to harder problems.

Reference excerpt

PHL 1222 also known as Q0151+048 or UM 144, is a radio-quiet binary quasar located in the constellation of Pisces. The quasar has a redshift of (z) 1.91 and was first discovered in January 1990 by astronomers Georges Meylan, Peter Shaver and Stanislav Djorgovski.

Description PHL 1222 is described having V-band magnitudes of 17.6 and 21.25 respectively. When observed, the quasars are separated into two individual components. One of the components (B) is shown to have a flat continuum while the other (A), has continuum colors described changing from blue to red with its flux level twice as high. It is suggested PHL 1222 might be a gravitationally lensed quasar candidate suggested by Meylan, who noticed a few objects encircling the component of the primary quasar, but however based on the continuum differences and the emission line showing widths described larger in the spectra of component B, he and his team concluded they are a quasar pair. According to observations, Meylan also found PHL 1222 is relatively young, with a separation gap of 3.3 arcseconds, estimating around 100,000-300,000 light-years apart. He suggested they might be formed by tidal interactions. The host galaxy of the primary quasar of the PHL 1222 system is described as extremely luminous according to observations obtained by Nordic Optical Telescope, with A-B magnitudes of -24.0, detected in photometric system bands. It is said to be a massive elliptical galaxy in early evolution stages based on a de Vaucouleurs profile with a star population between 10 and 100 million years old, while the host galaxy of the secondary quasar is found very faint by 3.2 magnitudes. Additionally, the primary quasar host displays extended continuum radio emission described as slight elongated with a position angle of 20° east of north. The supermassive black hole masses for both objects are estimated to be 109.33 and 108.38 M☉ with dark matter halo masses measuring to be 1033.74 and 1013.13 M☉ based on correlation trends. PHL 1222 shows a number of rich absorption line systems in its spectrum. When observed, the absorption line systems are found to be located various redshifts at (z) 1.929, 1.560, 1,618, 1.933 and 1.931, with mini broad absorption cerium lines described as a blend result of four absorption systems lying between 1.65 and 1.66. Further evidence showed there is a striking feature in one of the absorption lines centering at ʎ3567. This absorption line is described as strong, with it splitting into three different components and four sets of closely packed doublets. The first component is described as a Lyman-alpha feature while the other three are magnesium ions. These absorption systems are likely created by either accretion of interstellar medium or ejection of an interstellar cloud from the quasar via radiation pressure.

References

External links PHL 1222 on NASA/IPAC Database PHL on SIMBAD website

Illustrations

Worked examples

Example 1 — a first encounter with PHL 1222

Start with the simplest possible case. Write down what PHL 1222 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 PHL 1222 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 PHL 1222 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 PHL 1222

In research: PHL 1222 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 PHL 1222 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: PHL 1222 is common in secondary-school and first-year university syllabi. It links to neighbouring topics Astronomical objects discovered in 1990, Pisces (constellation), Principal Galaxies Catalogue objects, so understanding it makes those chapters shorter.
In everyday life: Look for PHL 1222 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 PHL 1222 in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what PHL 1222 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 PHL 1222 out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is PHL 1222 in simple terms?

Why does PHL 1222 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 PHL 1222?

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 PHL 1222.