Red nugget

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Red nuggets is the nickname given to rare, unusually small galaxies packed with large amounts of red stars that were originally observed by Hubble Space Telescope in 2005 in the young universe. [1] They are ancient remnants of the first massive galaxies. [2] The environments of red nuggets are usually consistent with the general elliptical galaxy population. [3] Most red nuggets have merged with other galaxies, but some managed to stay unscathed. [4]

Contents

Naming

Red nuggets are not only nicknamed for their size and color, but also for how precious the discovery is to curious astronomers since it challenged current theories at the time the term was coined on galaxy formation. [1]

Formation of red nuggets

Red nuggets are formed from blue nuggets. Blue nuggets are early, stream-fed, star-forming systems that are quenched inside-out within the inner kiloparsec (kpc) and dissipatively compacted into red nuggets at their peak of gas compaction. The compaction of the blue nugget happens at an approximately constant specific star formation rate (or SFR). The quenching of the blue nugget happens at a completely constant stellar surface density. Galaxies with more mass quench earlier than galaxies with low amounts of mass because galaxies with low amounts of mass try to quench several times. The compaction happens due to a fierce period of inflow involving (mostly small) mergers and counter-rotating streams or recycled gas. It is also frequently associated with extreme disc instability. The quenching happens because of the extremely high SFR, stellar and supernova feedback, and possibly also active galactic nuclei feedback due to the high gas density in the center of the red nugget. [5] [6]

Star formation

Data from NASA's Chandra X-Ray Observatory observing the red nuggets Mrk 1216 and PGC 032673 has shown that the central black holes suppress star formation in red nuggets with their heat and feed on the gas surrounding them. [7] [8] [9] This brings up the intriguing question on how they could possibly be packed so densely with stars. Results show that red nuggets may have untapped stellar "fuel" to produce their unusually large number of stars. [10] Another theory says that red nuggets are young elliptical galaxies, therefore forming the same way those do. [11]

Sloan Digital Sky Survey

A team led by Ivana Damjanov found over 600 red nugget candidates in the Sloan Digital Sky Survey (SDSS) database, of which 9 were confirmed as red nuggets. [12] These red nuggets have been missed so long because, due to their extremely small size, they look like stars in pictures. But their spectra shows what they really are. [13] Damjanov expressed how truly amazing the discovery was when she said, "Looking for 'red nuggets' in the Sloan Digital Sky Survey was like panning a riverbed, washing away silt and mud to uncover bits of gold". [14]

Before Damjanov and her team had thought to look through the immense database of the SDSS, no one could find the elusive galaxies after their original discovery in 2005. [15] [16]

See also

Related Research Articles

<span class="mw-page-title-main">Galaxy formation and evolution</span>

The study of galaxy formation and evolution is concerned with the processes that formed a heterogeneous universe from a homogeneous beginning, the formation of the first galaxies, the way galaxies change over time, and the processes that have generated the variety of structures observed in nearby galaxies. Galaxy formation is hypothesized to occur from structure formation theories, as a result of tiny quantum fluctuations in the aftermath of the Big Bang. The simplest model in general agreement with observed phenomena is the Lambda-CDM model—that is, clustering and merging allows galaxies to accumulate mass, determining both their shape and structure. Hydrodynamics simulation, which simulates both baryons and dark matter, is widely used to study galaxy formation and evolution.

<span class="mw-page-title-main">Supermassive black hole</span> Largest type of black hole

A supermassive black hole is the largest type of black hole, with its mass being on the order of hundreds of thousands, or millions to billions, of times the mass of the Sun (M☉). Black holes are a class of astronomical objects that have undergone gravitational collapse, leaving behind spheroidal regions of space from which nothing can escape, including light. Observational evidence indicates that almost every large galaxy has a supermassive black hole at its center. For example, the Milky Way galaxy has a supermassive black hole at its center, corresponding to the radio source Sagittarius A*. Accretion of interstellar gas onto supermassive black holes is the process responsible for powering active galactic nuclei (AGNs) and quasars.

<span class="mw-page-title-main">Intermediate-mass black hole</span> Class of black holes with a mass range of 100 to 100000 solar masses

An intermediate-mass black hole (IMBH) is a class of black hole with mass in the range 102–105 solar masses: significantly higher than stellar black holes but lower than the 105–109 solar mass supermassive black holes. Several IMBH candidate objects have been discovered in the Milky Way galaxy and others nearby, based on indirect gas cloud velocity and accretion disk spectra observations of various evidentiary strength.

<span class="mw-page-title-main">NGC 1427</span> Galaxy in the constellation Fornax

NGC 1427 is a low-luminosity elliptical galaxy located approximately 71 million light-years away from Earth. It was discovered by John Frederick William Herschel on November 28, 1837. It is a member of the Fornax Cluster. The galaxy has a stellar mass of 7.9 × 1010M☉, and a total mass of 9.4 × 1010M☉. However, the mass of the dark matter halo surrounding the galaxy is around 4.3 × 1012M☉.

<span class="mw-page-title-main">Hanny's Voorwerp</span> Astronomical object appearing as a bright blob, discovered by Hanny van Arkel

Hanny's Voorwerp is a type of astronomical object called a quasar ionization echo. It was discovered in 2007 by Dutch schoolteacher Hanny van Arkel while she was participating as a volunteer in the Galaxy Zoo project, part of the Zooniverse group of citizen science websites. Photographically, it appears as a bright blob close to spiral galaxy IC 2497 in the constellation Leo Minor.

<span class="mw-page-title-main">Sérsic profile</span>

The Sérsic profile is a mathematical function that describes how the intensity of a galaxy varies with distance from its center. It is a generalization of de Vaucouleurs' law. José Luis Sérsic first published his law in 1963.

<span class="mw-page-title-main">Arp 187</span> Radio galaxy and merger remnant

Arp 187 is a radio galaxy and merger remnant located in the constellation Eridanus. It is an interacting galaxy pair (MCG-02-13-040). It is included in the Atlas of Peculiar Galaxies in the category galaxies with narrow filaments.

<span class="mw-page-title-main">NGC 4596</span> Galaxy in the constellation Virgo

NGC 4596 is a barred lenticular galaxy located about 55 million light-years away in the constellation Virgo. NGC 4596 was discovered by astronomer William Herschel on March 15, 1784. NGC 4596 is a member of the Virgo Cluster and has an inclination of about 38°.

<span class="mw-page-title-main">NGC 1270</span> Galaxy in the constellation Perseus

NGC 1270 is an elliptical galaxy located about 250 million light-years away in the constellation Perseus. It was discovered by astronomer Heinrich d'Arrest on February 14, 1863. NGC 1270 is a member of the Perseus Cluster and has an estimated age of about 11 billion years. However, Greene et al. puts the age of NGC 1270 at about 15.0 ± 0.50 Gy.

<span class="mw-page-title-main">NGC 1278</span> Galaxy in the constellation Perseus

NGC 1278 is an elliptical galaxy located about 230 million light-years away in the constellation Perseus. NGC 1278 was discovered by astronomer Heinrich d'Arrest on February 14, 1863. It was then rediscovered by astronomer Guillaume Bigourdan on October 22, 1884 and was later listed as IC 1907. NGC 1278 is a member of the Perseus Cluster and is a low-luminosity AGN (LLAGN).

<span class="mw-page-title-main">NGC 1281</span> Galaxy in the constellation Perseus

NGC 1281 is a compact elliptical galaxy located about 200 million light-years away in the constellation Perseus. NGC 1281 was discovered by astronomer John Dreyer on December 12, 1876. It is a member of the Perseus Cluster.

<span class="mw-page-title-main">NGC 708</span> Galaxy in the constellation Andromeda

NGC 708 is an elliptical galaxy located 240 million light-years away in the constellation Andromeda and was discovered by astronomer William Herschel on September 21, 1786. It is classified as a cD galaxy and is the brightest member of Abell 262. NGC 708 is a weak FR I radio galaxy and is also classified as a type 2 Seyfert galaxy.

<span class="mw-page-title-main">NGC 5322</span> Galaxy in the constellation Ursa Major

NGC 5322 is an elliptical galaxy located in the constellation Ursa Major. It is located at a distance of circa 80 million light years from Earth, which, given its apparent dimensions, means that NGC 5322 is about 140,000 light years across. It was discovered by William Herschel on March 19, 1790.

<span class="mw-page-title-main">NGC 4074</span> Galaxy in the constellation Coma Berenices

NGC 4074 is a peculiar lenticular galaxy located 310 million light-years away in the constellation Coma Berenices. It was discovered by astronomer William Herschel on April 27, 1785 and is a member of the NGC 4065 Group.

<span class="mw-page-title-main">NGC 4800</span> Galaxy in constellation Canes Venatici

NGC 4800 is an isolated spiral galaxy in the constellation Canes Venatici, located at a distance of 95 megalight-years from the Milky Way. It was discovered by William Herschel on April 1, 1788. The morphological classification of this galaxy is SA(rs)b, indicating a spiral galaxy with no visual bar at the nucleus (SA), an incomplete ring structure (rs), and moderately-tightly wound spiral arms (b). The galactic plane is inclined to the line of sight by an angle of 43°, and the long axis is oriented along a position angle of 25°. There is a weak bar structure at the nucleus that is visible in the infrared.

<span class="mw-page-title-main">Teacup galaxy</span> Low redshift quasar in the constellation Boötes

The Teacup galaxy, also known as the Teacup AGN or SDSS J1430+1339 is a low redshift type 2 quasar, showing an extended loop of ionized gas resembling a handle of a teacup, which was discovered by volunteers of the Galaxy Zoo project and labeled as a Voorwerpje.

In astronomy, quenching is the process in which star formation shuts down in a galaxy. A galaxy that has been quenched is called a quiescent galaxy. Several possible astrophysical mechanisms have been proposed that could lead to quenching, which either result in a lack of cold molecular gas, or a decrease in how efficiently stars can form from molecular gas.

SDSS J1430+2303 is a galaxy with an active galactic nucleus that has been claimed to be undergoing a periodic brightness variability that is speeding up. One explanation for the purported behavior is that it could be a supermassive black hole binary. Initial trajectory models suggested the pair could be merging either before the end of 2022 or, alternatively, no later than 2025.

References

  1. 1 2 ""Red Nugget" galaxies were hiding in plain sight". Astronomy.com. Retrieved 2018-06-24.
  2. ↑ "Ancient "Red Nuggets" Detected --Relics of the 1st Massive Galaxies in the Universe with Gigantic Supermassive Black Holes". The Daily Galaxy --Great Discoveries Channel. Retrieved 2018-06-24.
  3. ↑ Oldham, Lindsay; Auger, Matthew W.; Fassnacht, Christopher D.; Treu, Tommaso; Brewer, Brendon J.; Koopmans, L. V. E.; Lagattuta, David; Marshall, Philip; McKean, John (2016-11-03). "Red nuggets grow inside-out: evidence from gravitational lensing". Monthly Notices of the Royal Astronomical Society. 465 (3): 3185–3202. arXiv: 1611.00008 . doi: 10.1093/mnras/stw2832 . ISSN   0035-8711. S2CID   118619501.
  4. ↑ "'Red nuggets' are galactic gold for astronomers" . Retrieved 2018-06-24.
  5. ↑ Zolotov, Adi; Dekel, Avishai; Mandelker, Nir; Tweed, Dylan; Inoue, Shigeki; DeGraf, Colin; Ceverino, Daniel; Primack, Joel R.; Barro, Guillermo (2015-05-06). "Compaction and quenching of high-z galaxies in cosmological simulations: blue and red nuggets". Monthly Notices of the Royal Astronomical Society. 450 (3): 2327–2353. arXiv: 1412.4783 . Bibcode:2015MNRAS.450.2327Z. doi: 10.1093/mnras/stv740 . hdl:10486/684489. ISSN   0035-8711. S2CID   118837407.
  6. ↑ Dekel, A.; Burkert, A. (2013-12-21). "Wet disc contraction to galactic blue nuggets and quenching to red nuggets". Monthly Notices of the Royal Astronomical Society. 438 (2): 1870–1879. arXiv: 1310.1074 . doi: 10.1093/mnras/stt2331 . ISSN   0035-8711. S2CID   41534885.
  7. ↑ Werner, N.; Lakhchaura, K.; Canning, R. E. A.; Gaspari, M.; Simionescu, A. (2018-07-01). "Digging for red nuggets: discovery of hot halos surrounding massive, compact, relic galaxies". Monthly Notices of the Royal Astronomical Society. 477 (3): 3886–3891. arXiv: 1711.09983 . Bibcode:2018MNRAS.477.3886W. doi: 10.1093/mnras/sty862 . ISSN   0035-8711. S2CID   73650059.
  8. ↑ "Supermassive Black Holes In Unusual 'Red Nugget' Galaxies Kill Star Formation". International Business Times. 2018-06-22. Retrieved 2018-06-24.
  9. ↑ Arce, Nicole (2018-06-22). "Red Nuggets Show Glimpse Into How Supermassive Black Holes Grow So Big". Tech Times. Retrieved 2018-06-26.
  10. ↑ "Chandra :: Photo Album :: Mrk 1216 :: June 21, 2018". chandra.harvard.edu. Retrieved 2018-06-24.
  11. ↑ "Digging up "red nuggets" in local elliptical galaxies". Astrobites. 2013-04-14. Retrieved 2018-06-24.
  12. ↑ Damjanov, Ivana; Chilingarian, Igor; Hwang, Ho Seong; Geller, Margaret J. (2013). "Discovery of Nine Intermediate-Redshift Compact Quiescent Galaxies in the Sloan Digital Sky Survey". The Astrophysical Journal. 775 (2): L48. arXiv: 1309.2948 . Bibcode:2013ApJ...775L..48D. doi:10.1088/2041-8205/775/2/L48. S2CID   119112132.
  13. ↑ "Researchers Discover Over 600 "Red Nugget" Galaxy Candidates". SciTechDaily. 2013-09-13. Retrieved 2018-07-02.
  14. ↑ ""Red Nugget" Galaxies Were Hiding in Plain Sight". www.cfa.harvard.edu/. 2013-09-30. Retrieved 2018-07-02.
  15. ↑ "The Eighth SDSS Data Release (DR8) - SDSS-III". www.sdss3.org. Retrieved 2018-07-02.
  16. ↑ "Archival research reveals a missing link". cfht.hawaii.edu. Retrieved 2018-07-02.
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