astronomy

NGC 7609

NGC 7609 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 NGC 7609 rather than just read about it. In short: NGC 7609 or known as Arp 150 and HCG 95A, is a large elliptical galaxy located in Pegasus. Its speed relative to the cosmic microwave background is 11,879 km/s, which corresponds the galaxy to be located 554 million light-years away from Earth (169.7 Mpc).

Key takeaways

NGC 7609 belongs to astronomy; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
Connect NGC 7609 to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of NGC 7609 from memory before moving on to harder problems.

Reference excerpt

NGC 7609 or known as Arp 150 and HCG 95A, is a large elliptical galaxy located in Pegasus. Its speed relative to the cosmic microwave background is 11,879 km/s, which corresponds the galaxy to be located 554 million light-years away from Earth (169.7 Mpc). NGC 7609 was discovered on October 5, 1864, by Albert Marth and included in Halton Arp's, Atlas of Peculiar Galaxies in galaxies that produces jets. With a surface brightness of apparent magnitude 14.59, NGC 7609 is classified as a low surface brightness galaxy (LSB). LSB galaxies are diffuse galaxies with surface brightness that is one less magnitude, of the night sky.

A pair of interacting galaxies A SDSS survey image and from the Hubble Space Telescope, showed that NGC 7609 is interacting with nearby galaxy, PGC 71077 (HCG 95C) whose spiral arms is currently being absorbed by the larger entity. A double-nuclei is present in HCG 95C, which is considered a merger remanent of two disk galaxies. Two tidal tails are also found in NGC 7609 and HCG 95C region, which seems to connect together, and there is a linear bridge between two galaxies indicating nuclear activity is taking place in HCG 95C. From the study written from Vilchez & Iglesias-Paramo in 1998, Hα emission is detected in the nuclei of both galaxies and also the larger tidal tails (the eastern tail). A long slit spectra of NGC 7609 shows, it exhibits red-shifted H-alpha +[N II] and [S II] emission lines that is indicative to a LINER-type AGN (Active Galactic Nucleus).

From the spatial profiles, this indicates non-nuclear starburst activity triggered by tidal forces while nuclear spectrum indicates non thermal activity. From the further IUE observations of HCG 95C, it presents a featureless continuum with transient outburst captured in one observation, showing galactic emission of red-shifted N v (1240 A) and C IV (1550 A). This result depicts HCG 95C is in the early stages of merging with NGC 7609. According to another study, it is suggested that a dwarf galaxy might have been created at the tip of the northern tidal tails.

Hickson 95 group NGC 7609 is a member of Hickson Compact Group 95. There are total of four galaxies in the group, in which the members are PGC 71074, PGC 71077 and PGC 71080. Of all the four galaxies, PGC 71080 (HCG 95B) is a foreground galaxy, as its line-of-sight velocity of 8000 km/s significantly differs from the velocity of the other members per published by Hickson et al.

Presence of ultra-diffuse galaxies around HCG 95 A study mentions there is a detection of 89 candidate ultra-diffuse galaxies (UDGs), around NGC 7609 and HCG 95, in which one is linked with. It is a gas-rich galaxy with H i mass 1.1 x 10 M⊙, detected by Very Large Array, and has a stellar mass of M 1.8 x 10 M⊙. This indicates that UDGs partially overlap with population of nearly dark galaxies found in deep H I surveys. The results show high abundance of blue UDGs in the HCG 95 field is favored by the poor galaxy cluster environment residing in H I-rich large-scale structures.

Supernova One supernova has been observed in NGC 7609. SN 1973M (type unknown, mag. 19) was discovered by Charles Kowal on 8 June 1973.

References

Illustrations

Worked examples

Example 1 — a first encounter with NGC 7609

Start with the simplest possible case. Write down what NGC 7609 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 NGC 7609 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 NGC 7609 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 NGC 7609

In research: NGC 7609 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 NGC 7609 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: NGC 7609 is common in secondary-school and first-year university syllabi. It links to neighbouring topics Arp objects, Astronomical objects discovered in 1864, Discoveries by Albert Marth, so understanding it makes those chapters shorter.
In everyday life: Look for NGC 7609 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 NGC 7609 in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what NGC 7609 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 NGC 7609 out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is NGC 7609 in simple terms?

Why does NGC 7609 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 NGC 7609?

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 NGC 7609.