astronomy

I Zwicky 1

I Zwicky 1 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 I Zwicky 1 rather than just read about it. In short: I Zwicky 1 (shortened to I Zw 1), also known as UGC 545, is a galaxy located in the constellation Pisces. It is located 847 million light-years from Earth and is said to be the nearest quasar (QSO) due to its high optical nuclear luminosity of MV = -23.8 mag.

Key takeaways

I Zwicky 1 belongs to astronomy; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
Connect I Zwicky 1 to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of I Zwicky 1 from memory before moving on to harder problems.

Reference excerpt

I Zwicky 1 (shortened to I Zw 1), also known as UGC 545, is a galaxy located in the constellation Pisces. It is located 847 million light-years from Earth and is said to be the nearest quasar (QSO) due to its high optical nuclear luminosity of MV = -23.8 mag.

Discovery I Zwicky 1 was discovered by Fritz Zwicky in 1964. According to Zwicky, the object is classified as a compact galaxy, whom he commented it as "Variable, blue, spherical, very compact, with a patchy halo." It is listed as the first object in the Zwicky catalogue. At the redshift of 0.0611, I Zwicky 1 shows spectral properties of high-redshift quasars that are blueshifted by 1,350 km-1 according to the study conducted by Buson & Ulrich in 1990. The photometric history of I Zwicky 1, dates back to 1909, where it has been investigated on Harvard photographic plates. The available data indicates the galaxy is variable and probably undergoes outbursts of about 0.7 mag above a brightness level that is itself variable by about 0.7 mag.

Characteristics

The nucleus of I Zwicky 1 is found to be active. It is classified as a prototypical narrow-line Seyfert 1 galaxy and contains high amounts of X-ray luminosity. The galaxy contains a peculiar spectrum, which in addition to the usual broad- and narrow-line regions, there are two emission regions emitting broad and blue shifted [O III] lines making it a peculiarly interesting object. The QSO sits inside its host galaxy which is revealed to be a face-on spiral galaxy. It shows two asymmetric spiral arms and knots of star formation. This makes I Zwicky 1 an ideal candidate for studying properties of QSO hosts. It is also possible that certain tidal interactions triggers activity in I Zwicky 1, both starburst and QSO. I Zwicky 1 is classified a Markarian galaxy (designated both Mrk 1502 and Mrk 9009). Compared to other galaxies, the nucleus emits excessive amounts of ultraviolet rays. This is caused by undergoing a strong starburst located in the central ring-like area of the galaxy.

Further study on I Zwicky 1 I Zwicky 1 shows existence of V-, R-, and H-bands with sturdy carbon monoxide (CO) featured in the J = 1-0 and J = 2-1 lines. When further observed, researchers found that the J = 1-0 line is brighter compared to the J = 2-1 line found with less luminosity. Given location in galactic molecular clouds, the carbon monoxide must be larger on the scale of the 26 kpc J = 1-0 beam size, with optical depth and being thermalized. Researchers who studied interstellar medium and star formation, found out a two-component model is required for I Zwicky 1 in which 2/3 of the far-infrared brightness originates in the disk and one-third originates from the nucleus. The star-forming rate, efficiency of the disk and the nucleus of I Zwicky 1 was estimated by researchers, whom they found that the values are similar to the luminosity of galaxies studied by IRAS. Overall, the disc star formation, is closer to topmost values of ~30 L_sun_/M_sun_ that is found inside galactic star-forming regions of the Milky Way such as M17 or W51. When looking at its nuclear near-infrared colors analysis, researchers suggest I Zwicky 1 has a combined quasar nucleus and defunct stellar component that matches about 10 to 20% of the flux density at 2.2 microns. This suggests the size of I Zwicky 1's molecular bulge is estimated to be 1" to 2" (1.2-2.4 kpc). But only the nucleus is revealed through optical spectrum and large X-ray luminosity. Millimeter Spectroscopy Further studies showed the mapping of 12CO (10) line emission in I Zwicky 1 whom researchers conducted observations with Institut de radioastronomie millimétrique (IRAM) millimeter interferometer on the Plateau de Bure, France, between January and February 1995. There, they placed four 15 m antennas in four different configurations. With 24 baselines provided by the four 15 m antennas, ranging from 24 to 288 m in length, they were supplied by SIS receivers with single-sideband (SSB) system temperatures of 170 K above the atmosphere. Located at redshift 0.0611, the observed frequency of I Zwicky 1 was 108.633 GHz. The CO maps were seen by the observations from IRAM 30m telescope. This resolution of a synthesized beam was uniform weighted of 19, but five resolution CLEAN maps (natural weighting) were made by spectral resolutions of 10 km s−1 and 40 km s−1 to examine the extended disk structure and velocity field. For the core component, researchers used the 19 resolution CLEANed maps with a spectral resolution of 20 km s−1. To investigate the structure dynamics of the nucleus, which they reckoned these velocity maps together with p-v diagrams alongside major and minor kinematic axes of I Zwicky 1. Near-Infrared Spectroscopy and Imaging I Zwicky 1 was observed by K-band (2.20 m) in January, 1995 with a MPE imaging spectrometer making use of 3D images with a 3.6 m telescope in Calar Alto, Spain. The observations in the H-band (1.65 m) on the other hand, were carried out in December 1995, at the William Herschel Telescope located in La Palma, Canary Islands. From two observations, researchers found that the image scale was 05 pixel−1 and total integration time on source was 4200 s and 1530 s for the K-band and H-band, respectively.

Molecular gas properties The properties of the molecular gas are important for acknowledging the total star formation and powering AGNs, given molecular clouds are the major reservoirs for such occurrences. According to researchers, looking inside the spiral arms of the QSO host galaxy, they detected the molecular line emission. Seeing this, they were able to break up the line emission into a separate core and disk components. Through analyzing the velocity field, a circumnuclear ring of molecular gas is found. It has a similar size to starburst rings in nearby galaxies. With a spatial resolution of 19 (2.2 kpc), no signs of gas is suggested streaming straight to the nucleus.

… excerpt ends here. Continue reading the full article.

Illustrations

Worked examples

Example 1 — a first encounter with I Zwicky 1

Start with the simplest possible case. Write down what I Zwicky 1 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 I Zwicky 1 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 I Zwicky 1 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 I Zwicky 1

In research: I Zwicky 1 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 I Zwicky 1 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: I Zwicky 1 is common in secondary-school and first-year university syllabi. It links to neighbouring topics IRAS catalogue objects, Markarian galaxies, Pisces (constellation), so understanding it makes those chapters shorter.
In everyday life: Look for I Zwicky 1 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 I Zwicky 1 in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what I Zwicky 1 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 I Zwicky 1 out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is I Zwicky 1 in simple terms?

Why does I Zwicky 1 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 I Zwicky 1?

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 I Zwicky 1.