astronomy

MACS0647-JD

MACS0647-JD 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 MACS0647-JD rather than just read about it. In short: MACS0647-JD is a galaxy with a spectroscopic redshift of z = 10.17, equivalent to a light travel distance of 13.34 billion light-years (4 billion parsecs). It formed about 460 million years after the Big Bang.

Key takeaways

MACS0647-JD belongs to astronomy; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
Connect MACS0647-JD to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of MACS0647-JD from memory before moving on to harder problems.

Reference excerpt

MACS0647-JD is a galaxy with a spectroscopic redshift of z = 10.17, equivalent to a light travel distance of 13.34 billion light-years (4 billion parsecs). It formed about 460 million years after the Big Bang.

Details JD refers to J-band Dropout – the galaxy was not detected in the so-called J-band (F125W), nor in 14 bluer Hubble filters. It only appeared in the two reddest filters (F140W and F160W). It is less than 600 light-years wide, and contains roughly a billion stars. The galaxy was discovered with the help of Cluster Lensing And Supernova survey with Hubble (CLASH), which uses massive galaxy clusters as cosmic telescopes to magnify distant galaxies behind them, an effect called gravitational lensing. Observations were recorded by the Wide Field Camera 3 on the Hubble Space Telescope, with support from the Spitzer Space Telescope. The location of the galaxy is in the constellation Camelopardalis, which is also the location of the gravitational lensing cluster that helped discover this galaxy: MACSJ0647+7015 at z = 0.591. MACS0647-JD was announced in November 2012, but by the next month UDFj-39546284, which was previously thought to be z = 10.3, was said to be at z = 11.9, although more recent analyses have suggested the latter is likely to be at a lower redshift. Infrared NIRCam imaging of MACS0647-JD by the James Webb Space Telescope (JWST) in September 2022 determined a photometric redshift of 10.6±0.3, in agreement with the previous Hubble estimate. Additional spectroscopic observations by JWST will be needed to accurately confirm the redshift of MACS0647-JD.

Spectroscopy by JWST NIRCam and NIRSpec observations of MACS0647-JD were performed in 2023 by the James Webb space telescope. The massive gravity of the MACS0647 galaxy cluster acts as a cosmic lens to bend and magnify the light from the more distant MACS0647-JD galactic system. Because of this gravitational lensing of the massive galaxy cluster MACS0647, the image of MACS0647-JD appears in three separate locations: JD1, JD2, and JD3. The three lensed images are magnified by factors of eight, five and two, respectively. The NIRCam imaging observations were able to spatially resolve the galaxy MACS0647-JD into two components A and B. Spectroscopy of component A yields a spectroscopic redshift of z = 10.17 based on 7 resolve emission lines in the rest-frame ultraviolet (UV) and blue optical: CIII] λλ 1907,1909, [O II] λ3727, [Ne III] λ3869, [Ne III] λ3968, Hδ λ4101, Hγ λ4340, et [O III] λ4363. The MACS0647-JD galaxy, given its spectral shift, is therefore observed just 460 million years after the Big Bang. MACS0647-JD has a stellar mass log(M⋆/ M☉) = 8.1 ± 0.3, which is equivalent to 126 million solar masses.

See also List of the most distant astronomical objects Farthest galaxies

References

External links Media related to MACS0647-JD at Wikimedia Commons NASA Great Observatories Find Candidate for Most Distant Object in the Universe to Date European Space Agency – Galaxy cluster MACS J0647.7+7015 [CZC2013] MACS0647-JD1 at SIMBAD Astronomical Database

Illustrations

Worked examples

Example 1 — a first encounter with MACS0647-JD

Start with the simplest possible case. Write down what MACS0647-JD 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 MACS0647-JD 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 MACS0647-JD 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 MACS0647-JD

In research: MACS0647-JD 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 MACS0647-JD 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: MACS0647-JD is common in secondary-school and first-year university syllabi. It links to neighbouring topics Camelopardalis, Dwarf galaxies, so understanding it makes those chapters shorter.
In everyday life: Look for MACS0647-JD 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 MACS0647-JD in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what MACS0647-JD 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 MACS0647-JD out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is MACS0647-JD in simple terms?

Why does MACS0647-JD 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 MACS0647-JD?

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 MACS0647-JD.