• Source: Little red dot (galaxy)

Little red dots (LRDs) are a class of small, red-tinted galaxies discovered by the James Webb Space Telescope. Their discovery was published in March 2024, and they are currently poorly understood. They appear to have existed between 0.6 and 1.6 billion years after the Big Bang, from 13.2 to 12.2 billion years ago.
LRDs were first selected by photometric methods because they are blue in ultraviolet and red in the optical spectrum. But soon, 80% of them were found to have very broad Balmer emission lines, suggesting that they are active galactic nuclei (AGN) and host supermassive black holes at their center.
However, LRDs also exhibit properties that are difficult to explain within the AGN scenario. For example, they have a flat infrared spectrum and lack x-ray detection. LRDs also show very weak time variability, often seen in AGN observation.
Several models have been proposed to explain the observed properties of LRDs. The shape of the ultraviolet spectrum can be explained by the scattered AGN light or by the gray dust extinction law.
The gas in LRDs spins extremely fast, at around 3,000 km/h, when the typical gas flow is around 300 km/h. Some scientists argue that the gas is accelerated to these extreme speeds by spinning, supermassive black holes; it has also been argued that LRDs are extremely compact to spin at their speeds. Most are also small, usually around 2% of the radius of the Milky Way.




References






Further reading


Matthee, Jorryt; Naidu, Rohan P.; Brammer, Gabriel; Chisholm, John; Eilers, Anna-Christina; Goulding, Andy; Greene, Jenny; Kashino, Daichi; Labbe, Ivo; Lilly, Simon J.; Mackenzie, Ruari; Oesch, Pascal A.; Weibel, Andrea; Wuyts, Stijn; Xiao, Mengyuan (March 2024). "Little Red Dots: An Abundant Population of Faint Active Galactic Nuclei at z ∼ 5 Revealed by the EIGER and FRESCO JWST Surveys". The Astrophysical Journal. 963 (2): 129. arXiv:2306.05448. Bibcode:2024ApJ...963..129M. doi:10.3847/1538-4357/ad2345. ISSN 0004-637X.

Kata Kunci Pencarian:

• Riwayat versi Android
• Daftar penulis bacaan anak
• Daftar penghargaan dan nominasi yang diterima oleh BTS
• Astrobiologi
• Little red dot (galaxy)
• Red Dot (disambiguation)
• Milky Way
• Andromeda Galaxy
• Samsung Galaxy S5
• Samsung Galaxy
• Guardians of the Galaxy Vol. 2
• Kathleen Barr
• League of Legends
• Night sky