astronomy

Markarian 590

Markarian 590 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 Markarian 590 rather than just read about it. In short: Markarian 590, also known as NGC 863, NGC 866, and NGC 885, is an unbarred spiral galaxy located in the constellation Cetus. It is located at a distance of about 300 million light years from Earth, which, given its apparent dimensions, means that NGC 863 is about 110,000 light years across.

Key takeaways

Markarian 590 belongs to astronomy; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
Connect Markarian 590 to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of Markarian 590 from memory before moving on to harder problems.

Reference excerpt

Markarian 590, also known as NGC 863, NGC 866, and NGC 885, is an unbarred spiral galaxy located in the constellation Cetus. It is located at a distance of about 300 million light years from Earth, which, given its apparent dimensions, means that NGC 863 is about 110,000 light years across. It is a changing look Seyfert galaxy.

Observational history Markarian 590 was discovered by William Herschel on 6 January 1785. The galaxy was also discovered independently by Lewis Swift on 3 October 1886, while he also catalogued it again as a different galaxy on 31 October 1886, and thus the galaxy is listed three times in the New General Catalogue. John Louis Emil Dreyer described it as very faint, round, brighter middle, stellar.

Supernova One supernova has been observed in Markarian 590:

SN 2018djd is a Type Ia supernova discovered by All Sky Automated Survey for SuperNovae (ASAS-SN) on 12 July 2018. The supernova was detected in images obtained on 10 July 2018, when it had a magnitude of 16.5. It reached a maximum apparent magnitude of 15.4.

Characteristics

The nucleus of Markarian 590 has been found to be active. The most accepted theory for the energy source of active galactic nuclei is the presence of an accretion disk around a supermassive black hole. The mass of the black hole in the centre of NGC 4593 is estimated to be (47.5±7.4)×106 M☉ based on reverberation mapping. The active galactic nucleus (AGN) of Markarian 590 has been categorised as change looking. This category of Seyfert galaxies is characterised by a change in the spectrum, with the broad emission lines disappearing or appearing, and thus changing the galaxy from to type I to type II and vice versa. Markarian 590 was originally characterised as a type I Seyfert galaxy, but later observations categorised the galaxy as type 1.5 and type 1.9-2. The broad line emission of Markarian 590 strengthened by a factor of tens from the 1970s to the 1990s and then decreased about 100 times in the 2000s in optical, UV, and X-ray wavelengths, and the broad component of the Hβ emission line disappeared completely. Observations by Suzaku X-ray satellite in 2011 revealed that the soft X-ray excess emission could no longer be detected, while the X-ray continuum flux had minimal change. The X-ray spectrum does not show evidence of obstruction; instead the variation is caused by a change in accretion rate. Observations of the galaxy in the infrared wavelengths revealed a sharp decrease in luminosity between 2000 and 2001. Also, during the low activity period, the radius of the circumnuclear dust torus decreased to 32 light days. In 2014, the soft excess emission had reappeared in observations by Chandra X-ray Observatory, as well as the broad MgII emission line. The radio emission of the galaxy is concentrated to a single core source, and extends to two components at a radius of about 2 arcsec (~1 kpc) and 6 arcsec (~3 kpc) from the core, that probably are related to the ring-like molecular gas structures observed in CO(3-2) imaging. The outer gas ring is probably related to the spiral arms of the galaxy while the inner ring is related to faint dust lanes. The central molecular gas mass is estimated to be less than 1.6×105 M☉, not significantly less than other AGNs. A faint parsec-scale radio jet extending 2.8 mas to the north has been detected using very-long-baseline interferometry. The radio emission exhibits long term variation that follows that of the other wavelengths. X-ray observations of the galaxy has shown the presence of ultra fast outflows, in the form of blueshifted absorption lines of O viii, Ne ix, Si xiv, and Mg xii.

References

External links

Markarian 590 on WikiSky: DSS2, SDSS, GALEX, IRAS, Hydrogen α, X-Ray, Astrophoto, Sky Map, Articles and images NGC 863 on SIMBAD

Illustrations

Worked examples

Example 1 — a first encounter with Markarian 590

Start with the simplest possible case. Write down what Markarian 590 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 Markarian 590 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 Markarian 590 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 Markarian 590

In research: Markarian 590 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 Markarian 590 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: Markarian 590 is common in secondary-school and first-year university syllabi. It links to neighbouring topics Astronomical objects discovered in 1785, Cetus (constellation), Discoveries by William Herschel, so understanding it makes those chapters shorter.
In everyday life: Look for Markarian 590 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 Markarian 590 in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what Markarian 590 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 Markarian 590 out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is Markarian 590 in simple terms?

Why does Markarian 590 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 Markarian 590?

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 Markarian 590.