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

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, that 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, not even light. Observational evidence indicates that almost every large galaxy has a supermassive black hole at its center. For example, the Milky Way has a supermassive black hole in its Galactic 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 more than stellar black holes but less than the 105–109 solar mass supermassive black holes. Several IMBH candidate objects have been discovered in our 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">Hanny's Voorwerp</span> Astronomical object appearing as a bright blob, discovered by Hanny van Arkel

Hanny's Voorwerp, is a rare 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">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.

The KBC Void is an immense, comparatively empty region of space, named after astronomers Ryan Keenan, Amy Barger, and Lennox Cowie, who studied it in 2013. The existence of a local underdensity has been the subject of many pieces of literature and research articles.

<span class="mw-page-title-main">NGC 4596</span> Barred lenticular 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> Elliptical 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 3860</span> Spiral galaxy in the constellation Leo

NGC 3860 is a spiral galaxy located about 340 million light-years away in the constellation Leo. NGC 3860 was discovered by astronomer William Herschel on April 27, 1785. The galaxy is a member of the Leo Cluster and is a low-luminosity AGN (LLAGN). Gavazzi et al. however classified NGC 3860 as a strong AGN which may have been triggered by a supermassive black hole in the center of the galaxy.

<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> Elliptical 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.

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">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 a process in which a galaxy loses cold gas, thus strongly suppressing star formation, because stars are formed from Nebulae and Nebulae are formed from accumulated Interstellar gas in the Interstellar medium (ISM). Evidence suggests that active supermassive black holes drive the process.

References

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