Quenching (astronomy)

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In astronomy, quenching is the process in which star formation shuts down in a galaxy. A galaxy that has been quenched (with little active star formation) is called a quiescent galaxy. [1] 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.

Contents

Quenching mechanisms

Active supermassive black holes

Evidence suggests that active supermassive black holes may drive quenching. The strong jets of some active supermassive black holes may heat up cold gas, thus suppressing star formation. [2] [3] [4] [5]

Environmental quenching

Several proposed galaxy quenching mechanisms rely on the environment a galaxy is situated in. One example of this is when a galaxy passes through a dense intracluster or intergalactic medium. The motion of the galaxy through this medium creates a ram pressure force which can strip gas away from the galaxy. Through this mechanism, known as ram pressure stripping, galaxies can be depleted of gas. [6] [7]

Galaxy Mergers

Inflows of gas from galaxy mergers can activate supermassive black holes within galaxies, thereby resulting in quenching via feedback from active galactic nuclei jets. [8] [9] Merger events can also trigger rapid bursts of star formation. This rapid star formation can lead to high rates of events like supernovae, which disrupt cold gas. This quenched state is sometimes called a post-starburst galaxy. [10] [11]

Morphological quenching

In morphological quenching, a galaxy’s evolution from a disk to a spheroid can reduce the efficiency of star formation over time, leading to lowered rates of star formation. [12]

Reionization

In the Epoch of Reionization, the first generation of stars heated gas throughout the universe. This process is thought to have quenched some smaller dwarf galaxies with small cold gas reservoirs.

Quenching and galaxy evolution

The process of quenching is connected to the observed dichotomy between massive galaxies of red elliptical galaxies, which have little active star formation, and blue spiral galaxies, with active star formation. One common evolutionary path on the galaxy color–magnitude diagram may start with a blue spiral galaxy with much star formation. The black hole at its center may start growing rapidly, and somehow start quenching the galaxy, which relatively quickly transitions through the "green valley", ending up more red. [2] [3]

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">Galaxy</span> Large gravitationally bound system of stars and interstellar matter

A galaxy is a system of stars, stellar remnants, interstellar gas, dust, and dark matter bound together by gravity. The word is derived from the Greek galaxias (γαλαξίας), literally 'milky', a reference to the Milky Way galaxy that contains the Solar System. Galaxies, averaging an estimated 100 million stars, range in size from dwarfs with less than a thousand stars, to the largest galaxies known – supergiants with one hundred trillion stars, each orbiting its galaxy's center of mass. Most of the mass in a typical galaxy is in the form of dark matter, with only a few percent of that mass visible in the form of stars and nebulae. Supermassive black holes are a common feature at the centres of galaxies.

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.

<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">Galactic Center</span> Rotational center of the Milky Way galaxy

The Galactic Center is the barycenter of the Milky Way and a corresponding point on the rotational axis of the galaxy. Its central massive object is a supermassive black hole of about 4 million solar masses, which is called Sagittarius A*, a compact radio source which is almost exactly at the galactic rotational center. The Galactic Center is approximately 8 kiloparsecs (26,000 ly) away from Earth in the direction of the constellations Sagittarius, Ophiuchus, and Scorpius, where the Milky Way appears brightest, visually close to the Butterfly Cluster (M6) or the star Shaula, south to the Pipe Nebula.

<span class="mw-page-title-main">Galactic bulge</span> Tightly packed group of stars within a larger formation

In astronomy, a galactic bulge is a tightly packed group of stars within a larger star formation. The term almost exclusively refers to the central group of stars found in most spiral galaxies. Bulges were historically thought to be elliptical galaxies that happened to have a disk of stars around them, but high-resolution images using the Hubble Space Telescope have revealed that many bulges lie at the heart of a spiral galaxy. It is now thought that there are at least two types of bulges: bulges that are like ellipticals and bulges that are like spiral galaxies.

<span class="mw-page-title-main">Starburst galaxy</span> Galaxy undergoing an exceptionally high rate of star formation

A starburst galaxy is one undergoing an exceptionally high rate of star formation, as compared to the long-term average rate of star formation in the galaxy, or the star formation rate observed in most other galaxies.

<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">Sagittarius A*</span> Supermassive black hole at the center of the Milky Way

Sagittarius A*, abbreviated Sgr A*, is the supermassive black hole at the Galactic Center of the Milky Way. Viewed from Earth, it is located near the border of the constellations Sagittarius and Scorpius, about 5.6° south of the ecliptic, visually close to the Butterfly Cluster (M6) and Lambda Scorpii.

Luminous infrared galaxies or LIRGs are galaxies with luminosities, the measurement of brightness, above 1011 L☉. They are also referred to as submillimeter galaxies (SMGs) through their normal method of detection. LIRGs are more abundant than starburst galaxies, Seyfert galaxies and quasi-stellar objects at comparable luminosity. Infrared galaxies emit more energy in the infrared than at all other wavelengths combined. A LIRG's luminosity is 100 billion times that of the Sun.

<span class="mw-page-title-main">NGC 4194</span> Interacting galaxy pair in the constellation of Ursa Major

NGC 4194, the Medusa merger, is a galaxy merger in the constellation Ursa Major about 128 million light-years (39.1 Mpc) away. It was discovered on April 2, 1791 by German-British astronomer William Herschel. Due to its disturbed appearance, it is object 160 in Halton Arp's 1966 Atlas of Peculiar Galaxies.

<span class="mw-page-title-main">NGC 4102</span> Galaxy in the constellation Ursa Major

NGC 4102 is an intermediate barred spiral galaxy located in the northern constellation of Ursa Major. It is visible in a small telescope and has an apparent visual magnitude of 11.2. The galaxy was discovered April 12, 1789 by William Herschel. J. L. E. Dreyer described it as "bright, pretty small, round, brighter middle and bright nucleus". This galaxy is located at a distance of 60 million light years and is receding with a heliocentric radial velocity of 837 km/s. It is a member of the Ursa Major group of galaxies.

<span class="mw-page-title-main">Nuclear star cluster</span> Star cluster in the center of a galaxy

A nuclear star cluster (NSC) or compact stellar nucleus is a star cluster with high density and high luminosity near the center of mass of most galaxies.

<span class="mw-page-title-main">Galactic superwind</span> Strong stellar winds of a galactic scale in size

A galactic superwind, or just galactic wind, is a high velocity stellar wind emanating from either newly formed massive stars, spiral density waves, or as the result of the effects of supermassive black holes. They are normally observed in starburst galaxies.

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. They are ancient remnants of the first massive galaxies. The environments of red nuggets are usually consistent with the general elliptical galaxy population. Most red nuggets have merged with other galaxies, but some managed to stay unscathed.

<span class="mw-page-title-main">NGC 7469</span> Galaxy located in the constellation Pegasus

NGC 7469 is an intermediate spiral galaxy in the constellation of Pegasus. NGC 7469 is located about 200 million light-years away from Earth, which means, given its apparent dimensions, that NGC 7469 is approximately 90,000 light-years across. It was discovered by William Herschel on November 12, 1784.

<span class="mw-page-title-main">NGC 7130</span> Galaxy in the constellation Piscis Austrinus

NGC 7130 is a spiral galaxy located in the constellation Piscis Austrinus. It is located at a distance of about 220 million light years from Earth, which, given its apparent dimensions, means that NGC 7130 is about 100,000 light years across. It was discovered by John Herschel on September 25, 1834, and discovered independently by Lewis Swift on September 17, 1897. The location of the galaxy given in the New General Catalogue was off by 30 arcminutes in declination from the location of the galaxy.

<span class="mw-page-title-main">NGC 7679</span> Galaxy in the constellation Pisces

NGC 7679 is a lenticular galaxy with a peculiar morphology in the constellation Pisces. It is located at a distance of about 200 million light years from Earth, which, given its apparent dimensions, means that NGC 7679 is about 60,000 light years across. It was discovered by Heinrich d'Arrest on September 23, 1864. The total infrared luminosity is 1011.05 L☉, and thus it is categorised as a luminous infrared galaxy. NGC 7679 is both a starburst galaxy and a Seyfert galaxy.

<span class="mw-page-title-main">QSO J0100-2708</span>

QSO J0100-2708 is a quasar located in the constellation Sculptor. With a redshift of 3.520000, the object is located 11.5 billion light-years away from Earth and contains a flat-spectrum radio source found brighter compared to S4.8 GHz=65 mJy.

References

Schawinski, Kevin; Urry, C. Megan; Simmons, Brooke D.; Fortson, Lucy; Kaviraj, Sugata; Keel, William C.; Lintott, Chris J.; Masters, Karen L.; Nichol, Robert C.; Sarzi, Marc; Skibba, Ramin (2014-05-01). "The green valley is a red herring: Galaxy Zoo reveals two evolutionary pathways towards quenching of star formation in early- and late-type galaxies". Monthly Notices of the Royal Astronomical Society. 440 (1): 889–907. arXiv: 1402.4814 . Bibcode:2014MNRAS.440..889S. doi: 10.1093/mnras/stu327 . ISSN   0035-8711.

  1. ↑ Cook, Ben (Nov 24, 2014). "Over My Dead Body: Keeping Dead Galaxies from Forming New Stars". Astrobites. Retrieved July 5, 2024.
  2. 1 2 "Galactic star formation and supermassive black hole masses". phys.org. Retrieved 2020-07-17.
  3. 1 2 Chen, Zhu; Faber, S. M.; Koo, David C.; Somerville, Rachel S.; Primack, Joel R.; Dekel, Avishai; Rodríguez-Puebla, Aldo; Guo, Yicheng; Barro, Guillermo; Kocevski, Dale D.; Wel, A. van der (2020-07-07). "Quenching as a Contest between Galaxy Halos and Their Central Black Holes". The Astrophysical Journal. 897 (1): 102. arXiv: 1909.10817 . Bibcode:2020ApJ...897..102C. doi: 10.3847/1538-4357/ab9633 . ISSN   1538-4357. S2CID   202734402.
  4. ↑ Dubois, Yohan; Gavazzi, Raphaël; Peirani, Sébastien; Silk, Joseph (2013-08-21). "AGN-driven quenching of star formation: morphological and dynamical implications for early-type galaxies". Monthly Notices of the Royal Astronomical Society. 433 (4): 3297–3313. doi:10.1093/mnras/stt997. ISSN   1365-2966.
  5. ↑ Williams, Matt; Today, Universe. "Supermassive black holes shut down star formation during cosmic noon, says astronomer". phys.org. Retrieved 2024-07-06.
  6. ↑ Proctor, Katy (Mar 26, 2022). "The end of star formation in satellites: where and when?". Astrobites. Retrieved July 5, 2024.
  7. ↑ Roberts, I. D.; van Weeren, R. J.; McGee, S. L.; Botteon, A.; Ignesti, A.; Rottgering, H. J. A. (August 2021). "LoTSS jellyfish galaxies: II. Ram pressure stripping in groups versus clusters". Astronomy & Astrophysics. 652: A153. arXiv: 2106.06315 . Bibcode:2021A&A...652A.153R. doi:10.1051/0004-6361/202141118. ISSN   0004-6361.
  8. ↑ Samantha Mathewson (2023-01-10). "Hungry black holes trapped in an intimate dance feast on leftovers from a galactic merger". Space.com. Retrieved 2024-07-06.
  9. ↑ Rodríguez Montero, Francisco; Davé, Romeel; Wild, Vivienne; Anglés-Alcázar, Daniel; Narayanan, Desika (2019-12-01). "Mergers, starbursts, and quenching in the simba simulation". Monthly Notices of the Royal Astronomical Society. 490 (2): 2139–2154. doi:10.1093/mnras/stz2580. ISSN   0035-8711.
  10. ↑ Booth, C. M.; Schaye, Joop (2013-05-15). "The interaction between feedback from active galactic nuclei and supernovae". Scientific Reports. 3 (1): 1738. arXiv: 1203.3802 . Bibcode:2013NatSR....E1738B. doi:10.1038/srep01738. ISSN   2045-2322.
  11. ↑ Ramasawmy, Joanna (Feb 1, 2018). "Post-starburst galaxies: the missing link in galaxy evolution?" . Retrieved July 5, 2024.
  12. ↑ Martig, Marie; Bournaud, Frédéric; Teyssier, Romain; Dekel, Avishai (2009-12-10). "Morphological Quenching of Star Formation: Making Early-Type Galaxies Red". The Astrophysical Journal. 707 (1): 250–267. arXiv: 0905.4669 . Bibcode:2009ApJ...707..250M. doi:10.1088/0004-637X/707/1/250. ISSN   0004-637X.
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