astronomy

SDSS J1011+5442

SDSS J1011+5442 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 SDSS J1011+5442 rather than just read about it. In short: SDSS J1011+5442 (full name SDSS J101152.98+544206.4) is a quasar located in the constellation of Ursa Major. The redshift of the object is (z) 0.246 and it was first discovered in the Sloan Digital Sky Survey (SDSS) by astronomers in 2003.

Key takeaways

SDSS J1011+5442 belongs to astronomy; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
Connect SDSS J1011+5442 to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of SDSS J1011+5442 from memory before moving on to harder problems.

Reference excerpt

SDSS J1011+5442 (full name SDSS J101152.98+544206.4) is a quasar located in the constellation of Ursa Major. The redshift of the object is (z) 0.246 and it was first discovered in the Sloan Digital Sky Survey (SDSS) by astronomers in 2003. This quasar has also been referred to as changing-look.

Description The active galactic nucleus (AGN) of the quasar has been described as changing-look. It was in a bright state when it was first observed in January 2003 as a Type 1 AGN, with its main optical spectrum displaying typical characteristics of a broad-line quasar, mainly broad emission lines and a blue continuum. When observed again in 2015, it was in a dim state, changing it to a Type 1.9 AGN from Type 1 AGN with the spectrum only displaying hydrogen alpha (Hα) emission lines at weaker state, while the hydrogen beta emission lines (Hβ) vanished completely. During its dim state, it exhibited the presence of Hα emission best described by a narrow single component, two narrow Gaussian components and a singe broad Gaussian component that is found offset by around 100 kilometers per seconds. By 2024, it had reverted to its original Type 1 state, with its Hβ lines appearing again. The mass of the central black hole of the quasar is estimated to be 7.28 ± 0.15 M☉ based on the M-sigma relation. Other studies estimated the black hole as 3.6 ± 0.2 × 107 M☉. A theory also suggested that its bright appearance is likely caused by a tidal disruption event (TDE) when its black hole rips apart a star that has passed too close to it. The host galaxy of SDSS J1011+5442 has been described as having an irregular appearance, suggesting it underwent a recent galaxy merger with another galaxy, which was confirmed based on the presence of tidal stream features. Other signs of the merger included a diffused tidal tail in the north, and a ring-like tidal feature orientated east to west. There is also the presence of doubly ionized oxygen radio emission. The total stellar mass of the quasar is estimated to be 1.011.090.93 × 1010 M☉. A study published in 2017 found SDSS J1011+5442 has low polarization levels ,which is usual for any of the Type 1 unobscured quasars. This indicates it is not caused by any obscuration in its torus or either its own broad line region. But it could also be that it was also seen at a low inclination angle so much that its scattering regions look as asymmetric away from the position of any lines of sight that crosses the torus region.

References

External links SDSS J1011+5442 on SIMBAD SDSS J1011+5442 on HyperLeda

Illustrations

Worked examples

Example 1 — a first encounter with SDSS J1011+5442

Start with the simplest possible case. Write down what SDSS J1011+5442 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 SDSS J1011+5442 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 SDSS J1011+5442 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 SDSS J1011+5442

In research: SDSS J1011+5442 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 SDSS J1011+5442 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: SDSS J1011+5442 is common in secondary-school and first-year university syllabi. It links to neighbouring topics Active galaxies, Astronomical objects discovered in 2003, Galaxy mergers, so understanding it makes those chapters shorter.
In everyday life: Look for SDSS J1011+5442 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 SDSS J1011+5442 in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what SDSS J1011+5442 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 SDSS J1011+5442 out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is SDSS J1011+5442 in simple terms?

Why does SDSS J1011+5442 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 SDSS J1011+5442?

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 SDSS J1011+5442.