Little red dot (galaxy)

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A little red dot galaxy (center) in false color Little red dot galaxy J1148-18404.jpg
A little red dot galaxy (center) in false color
False-color stamps of 20 little red dot galaxies Little red dot galaxy stamps 20 unlabeled.jpg
False-color stamps of 20 little red dot galaxies

Little red dots (LRDs) are a class of small, red-tinted galaxies discovered by the James Webb Space Telescope. [1] [2] [3] Their discovery was published in March 2024, and they are currently poorly understood. [4] 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. [1]

LRDs were first selected by photometric methods because they are blue in ultraviolet and red in the optical spectrum. [4] 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. [5]

However, LRDs also exhibit properties that are difficult to explain within the AGN scenario. For example, they have a flat infrared spectrum [6] and lack x-ray detection. [7] [8] LRDs also show very weak time variability, often seen in AGN observation. [9]

Several models have been proposed to explain the observed properties of LRDs. [10] [11] [12] The shape of the ultraviolet spectrum can be explained by the scattered AGN light [10] [11] or by the gray dust extinction law. [12]

The gas in LRDs spins extremely fast, at around 3,000 km/h, when the typical gas flow is around 300 km/h. [1] 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. [1] Most are also small, usually around 2% of the radius of the Milky Way. [3]

Likely local analogues of LRDs were discovered in a sample of Green Pea Galaxies (GP). These are broad-line AGN hosting Green Peas (BLGP) with V-shaped rest-frame UV-to-optical SEDs. Seven such V-shaped BLGPs were identified. These V-shaped BLGPs host over-massive black holes. [13]

Related Research Articles

An active galactic nucleus (AGN) is a compact region at the center of a galaxy that emits a significant amount of energy across the electromagnetic spectrum, with characteristics indicating that this luminosity is not produced by the stars. Such excess, non-stellar emissions have been observed in the radio, microwave, infrared, optical, ultra-violet, X-ray and gamma ray wavebands. A galaxy hosting an AGN is called an active galaxy. The non-stellar radiation from an AGN is theorized to result from the accretion of matter by a supermassive black hole at the center of its host galaxy.

Rychard J. Bouwens is an associate professor at Leiden University. He is also a former member of the Advanced Camera for Surveys Guaranteed Time Observation team and postdoctoral research astronomer at the University of California, Santa Cruz. He obtained his bachelor's degree in physics, chemistry, and mathematics from Hope College. He then went on to earn his Ph.D. in physics at the University of California, Berkeley under the supervision of Joseph Silk and also worked with Tom Broadhurst.

The Milky Way has several smaller galaxies gravitationally bound to it, as part of the Milky Way subgroup, which is part of the local galaxy cluster, the Local Group.

<span class="mw-page-title-main">MS 0735.6+7421</span> Galaxy cluster in the constellation Camelopardalis

MS 0735.6+7421 is a galaxy cluster located in the constellation Camelopardalis, approximately 2.6 billion light-years away. It is notable as the location of one of the largest central galactic black holes in the known universe, which has also apparently produced one of the most powerful active galactic nucleus eruptions discovered.

<span class="mw-page-title-main">WISE J031624.35+430709.1</span> Star in the constellation Perseus

WISE J031624.35+430709.1 is a brown dwarf of spectral class T8, located in constellation Perseus at approximately 106 light-years from Earth. It was one of the furthest T-class brown dwarfs known. In 2024 a T dwarf about 2 kpc distant, with a low-metallicity was discovered with the JWST. This brown dwarf is called JADES-GS-BD-9. Additional kpc distant T dwarfs were discovered by two teams, with UNCOVER-BD-1 being 4.5 or 4.8 kpc distant.

<span class="mw-page-title-main">CID-42</span> Galaxy quasar in the constellation Sextans

CID-42 is a galaxy quasar about 3.9 billion light years away in the constellation Sextans. It is believed to have a supermassive black hole at its center.

<span class="mw-page-title-main">Tidal disruption event</span> Pulling apart of a star by tidal forces when it gets too close to a supermassive black hole

A tidal disruption event (TDE) is a transient astronomical source produced when a star passes so close to a supermassive black hole (SMBH) that it is pulled apart by the black hole's tidal force. The star undergoes spaghettification, producing a tidal stream of material that loops around the black hole. Some portion of the stellar material is captured into orbit, forming an accretion disk around the black hole, which emits electromagnetic radiation. In a small fraction of TDEs, a relativistic jet is also produced. As the material in the disk is gradually consumed by the black hole, the TDE fades over several months or years.

Misty C. Bentz is an American astrophysicist and Professor of Physics and Astronomy at Georgia State University. She is best known for her work on supermassive black hole mass measurements and black hole scaling relationships.

<span class="mw-page-title-main">NGC 5728</span> Spiral galaxy in the constellation Libra

NGC 5728 is an active barred spiral galaxy located 146 million light years away in the southern constellation of Libra. It was discovered on May 7, 1787 by William Herschel. The designation comes from the New General Catalogue of J. L. E. Dreyer, published in 1888. It has an apparent visual magnitude of 13.40 and spans an angle of 3.4 arcminutes. The galaxy shows a red shift of 0.00935 and has a heliocentric radial velocity of 2,803 km/s. It has an estimated mass of 72 billion times the mass of the Sun and stretches around 30 kpc across.

A blanet is a member of a hypothetical class of exoplanets that directly orbit black holes.

<span class="mw-page-title-main">UHZ1</span> Background galaxy containing a quasar

UHZ1 is a background galaxy containing a quasar. At a redshift of approximately 10.1, UHZ1 is at a distance of 13.2 billion light-years, seen when our universe was about 3 percent of its current age. This redshift made it the most distant, and therefore earliest known quasar in the observable universe as of 2023. To detect this object, astronomers working at the Chandra X-ray Observatory used the Abell 2744's cluster mass as a gravitational lens in order to magnify distant objects directly behind it. At the time of discovery, it exceeded the distance record of QSO J0313−1806.

<span class="mw-page-title-main">Extended emission-line region</span> Interstellar clouds

An extended emission-line region (EELR) is a giant interstellar cloud ionized by the radiation of an active galactic nucleus (AGN) inside a galaxy or photons produced by the shocks associated with the radio jets. An EELR can appear as a resolved cloud in relative nearby galaxies and as narrow emission lines in more distant galaxies.

<span class="mw-page-title-main">IC 1623</span> Galaxy pair in the constellation Cetus

IC 1623 is a galaxy merger in the constellation Cetus. The galaxy lies about 250 million light years away from Earth, which means, given its apparent dimensions, that IC 1623 is approximately 115,000 light years across. It was discovered by Lewis Swift on November 19, 1897.

<span class="mw-page-title-main">IC 3528</span> Galaxy in the constellation Coma Berenices

IC 3528 is spiral galaxy located 660 million light-years away in the constellation of Coma Berenices. It lies near to another spiral galaxy NGC 4540, although the two of them are quite far. The object was discovered by Royal Harwood Frost on May 7, 1904. Although listed as a member in the Virgo Cluster Catalogue as VCC 1593, it is not a member of the Virgo cluster but a background galaxy.

<span class="mw-page-title-main">Markarian 817</span> Barred spiral galaxy in the constellation Draco

Markarian 817 is a barred spiral galaxy located in the constellation Draco. It is located 456 million light-years from Earth, which, given its apparent dimensions, means that Markarian 817 is about 80,000 light-years across. It is a Seyfert galaxy.

<span class="mw-page-title-main">UNCOVER-z12</span> Lyman-break galaxy in the constellation Sculptor

UNCOVER-z12 is a high-redshift Lyman-break galaxy discovered by the James Webb Space Telescope (JWST) during NIRCam imaging for the JWST Ultradeep NIRSpec and NIRCam Observations before the Epoch of Reionization (UNCOVER) project in November 2023. UNCOVER-z12 is within the Abell 2744 supercluster in the constellation Sculptor. It is the 5th-most distant object ever discovered as of 2024, and is estimated to be 32.21 giga-lightyears from Earth.

<span class="mw-page-title-main">SDSS J0849+1114</span> Trio of interacting galaxies in the constellation Cancer

SDSS J0849+1114 is a late-stage galaxy merger forming from a trio of galaxies located in the constellation of Cancer. At the redshift of 0.077, they are located 1.06 billion light-years from Earth. First discovered as a triple active galactic nucleus (AGN) candidate in a Sloan Digital Sky Survey study published in 2011, they received significant attention when astronomers discovered it harbors three supermassive black holes in its center.

<span class="mw-page-title-main">UNCOVER-BD-1</span> UNCOVER-BD-1 is a distant brown dwarf

UNCOVER-BD-1 is a distant brown dwarf. It is the most distant T dwarf discovered to date.

References

  1. 1 2 3 4 Boyle, Rebecca (2024-10-09). "The 'Beautiful Confusion' of the First Billion Years Comes Into View". Quanta Magazine. Retrieved 2024-10-18.
  2. ↑ "Little Red Dots: Stars or Black Holes?". NASA Space News. 2024-09-09. Retrieved 2024-10-18.
  3. 1 2 Pacucci, Fabio; Conversation, The. "Hidden, compact galaxies in the distant universe—searching for the secrets behind the little red dots". phys.org. Retrieved 2024-10-18.
  4. 1 2 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.
  5. ↑ Greene, Jenny E.; Labbe, Ivo; Goulding, Andy D.; Furtak, Lukas J.; Chemerynska, Iryna; Kokorev, Vasily; Dayal, Pratika; Volonteri, Marta; Williams, Christina C.; Wang 王, Bingjie 冰洁; Setton, David J.; Burgasser, Adam J.; Bezanson, Rachel; Atek, Hakim; Brammer, Gabriel (2024-03-01). "UNCOVER Spectroscopy Confirms the Surprising Ubiquity of Active Galactic Nuclei in Red Sources at z > 5". The Astrophysical Journal. 964 (1): 39. arXiv: 2309.05714 . Bibcode:2024ApJ...964...39G. doi: 10.3847/1538-4357/ad1e5f . ISSN   0004-637X.
  6. ↑ Williams, Christina C.; Alberts, Stacey; Ji, Zhiyuan; Hainline, Kevin N.; Lyu, Jianwei; Rieke, George; Endsley, Ryan; Suess, Katherine A.; Sun, Fengwu; Johnson, Benjamin D.; Florian, Michael; Shivaei, Irene; Rujopakarn, Wiphu; Baker, William M.; Bhatawdekar, Rachana (2024-06-01). "The Galaxies Missed by Hubble and ALMA: The Contribution of Extremely Red Galaxies to the Cosmic Census at 3 < z < 8". The Astrophysical Journal. 968 (1): 34. arXiv: 2311.07483 . Bibcode:2024ApJ...968...34W. doi: 10.3847/1538-4357/ad3f17 . ISSN   0004-637X.
  7. ↑ Ananna তনিমা তাসনিম, Tonima Tasnim অনন্যা; Bogdán, Ákos; Kovács, Orsolya E.; Natarajan, Priyamvada; Hickox, Ryan C. (2024-07-01). "X-Ray View of Little Red Dots: Do They Host Supermassive Black Holes?". The Astrophysical Journal Letters. 969 (1): L18. arXiv: 2404.19010 . Bibcode:2024ApJ...969L..18A. doi: 10.3847/2041-8213/ad5669 . ISSN   2041-8205.
  8. ↑ Yue, Minghao; Eilers, Anna-Christina; Ananna, Tonima Tasnim; Panagiotou, Christos; Kara, Erin; Miyaji, Takamitsu (2024-10-01). "Stacking X-Ray Observations of "Little Red Dots": Implications for Their Active Galactic Nucleus Properties". The Astrophysical Journal Letters. 974 (2): L26. arXiv: 2404.13290 . Bibcode:2024ApJ...974L..26Y. doi: 10.3847/2041-8213/ad7eba . ISSN   2041-8205.
  9. ↑ Kokubo, Mitsuru; Harikane, Yuichi (2024). "Challenging the AGN scenario for JWST/NIRSpec broad Hα emitters/Little Red Dots in light of non-detection of NIRCam photometric variability and X-ray". arXiv: 2407.04777 [astro-ph.GA].
  10. 1 2 Kocevski, Dale D.; Onoue, Masafusa; Inayoshi, Kohei; Trump, Jonathan R.; Arrabal Haro, Pablo; Grazian, Andrea; Dickinson, Mark; Finkelstein, Steven L.; Kartaltepe, Jeyhan S.; Hirschmann, Michaela; Aird, James; Holwerda, Benne W.; Fujimoto, Seiji; Juneau, Stéphanie; Amorín, Ricardo O. (2023-09-01). "Hidden Little Monsters: Spectroscopic Identification of Low-mass, Broad-line AGNs at z > 5 with CEERS". The Astrophysical Journal Letters. 954 (1): L4. arXiv: 2302.00012 . Bibcode:2023ApJ...954L...4K. doi: 10.3847/2041-8213/ace5a0 . ISSN   2041-8205.
  11. 1 2 Labbe, Ivo; Greene, Jenny E.; Bezanson, Rachel; Fujimoto, Seiji; Furtak, Lukas J.; Goulding, Andy D.; Matthee, Jorryt; Naidu, Rohan P.; Oesch, Pascal A.; Atek, Hakim; Brammer, Gabriel; Chemerynska, Iryna; Coe, Dan; Cutler, Sam E.; Dayal, Pratika (2023). "UNCOVER: Candidate Red Active Galactic Nuclei at 3 < z < 7 with JWST and ALMA". arXiv: 2306.07320 [astro-ph.GA].
  12. 1 2 Li, Zhengrong; Inayoshi, Kohei; Chen, Kejian; Ichikawa, Kohei; Ho, Luis C. (2024). "Little Red Dots: Rapidly Growing Black Holes Reddened by Extended Dusty Flows". arXiv: 2407.10760 [astro-ph.GA].
  13. ↑ Lin, Ruqiu; Zheng, Zhen-Ya; Jiang, Chunyan; Yuan, Fang-Ting; Ho, Luis C.; Wang, Junxian; Jiang, Linhua; Rhoads, James E.; Malhotra, Sangeeta (2024-12-11). "Discovery of Local Analogs to JWST's Little Red Dots". arXiv: 2412.08396 [astro-ph].

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