{"id":12322,"date":"2022-01-02T21:19:04","date_gmt":"2022-01-03T07:19:04","guid":{"rendered":"http:\/\/www.eaobservatory.org\/jcmt\/?page_id=12322"},"modified":"2022-01-10T13:39:53","modified_gmt":"2022-01-10T23:39:53","slug":"majors-massive-active-jcmt-observed-regions-of-star-formation","status":"publish","type":"page","link":"https:\/\/www.eaobservatory.org\/jcmt\/science\/large-programs\/majors-massive-active-jcmt-observed-regions-of-star-formation\/","title":{"rendered":"MAJORS: Massive, Active, JCMT-Observed Regions of Star formation"},"content":{"rendered":"

Determining the role of dense gas in star formation<\/strong><\/p>\n

We are observing a large, mass-selected sample of dust-continuum traced, star-forming molecular clouds in HCN J=3-2 and HCO+<\/sup> J=3-2 with \u2018\u016a\u2019\u016b. This sample includes clouds in the Central Molecular Zone (CMZ), the Inner Galaxy, and the Outer Galaxy. Dense gas is vital to the star-formation process, and high-resolution observations of this dense gas in a large sample of resolved star-forming sources is crucial to understanding its exact role in regulating star-formation efficiency.<\/p>\n

Predictive, empirical relationships of star formation, such as the Kennicutt-Schmidt law, are able to link the scaling of the star-formation rate surface density with the surface density of the gas. However, this relationship only holds for normal and dwarf galaxies, and becomes super-linear in starburst systems and breaks down on the smallest scales of individual giant molecular clouds. However, when dense-gas observations are used, these relationships survive, once again indicating the apparent importance of dense gas in the star-formation process.<\/p>\n

The key science outcomes and goals of this project are:<\/p>\n

    \n
  1. Understand the impact of Galactic environment on the physics of dense gas, allowing for an understanding of how dense gas is produced and intrinsically linked to star formation.<\/li>\n
  2. Distinguish between star-formation theories, and whether the star-formation rate is controlled by the free-fall time within bound structures or the amount of dense gas available for star formation.<\/li>\n
  3. Produce LIR<\/sub> \u2013 Lgas<\/sub> relationships linking resolved Galactic clumps, Galactic molecular clouds, extragalactic systems and ULIRGS to study the universality of the star-formation process.<\/li>\n
  4. Determine the cause of variations of the HCN\/HCO+<\/sup> ratio, and how it is linked to the physical conditions caused by Galactic environment.<\/li>\n
  5. Find a sample of extreme star-forming sources using maps of dense-gas mass fraction and a sample of Galactic mini-starbursts using a LIR<\/sub> \u2013 Lgas<\/sub> relationship produced using CO maps.<\/li>\n
  6. Link the clump-mass fraction to the star-formation efficiency and clump-formation efficiency.<\/li>\n
  7. Identify outflows and active regions of star formation and determine the infall rates of the gas into individual clumps<\/li>\n
  8. Provide a legacy sample matching those of extragalactic studies for future studies.<\/li>\n<\/ol>\n
    \"\"<\/a>

    LIR<\/sub> \u2013 LHCN<\/sub> relationship from Tan et al. (2018) spanning ten orders of magnitude in luminosity from Galactic clumps to high-redshift ULIRGs.<\/p><\/div>\n

    Coordinators:<\/strong>\u00a0David Eden (UK), Xue-Jian Jiang (EAO), James <\/span>Di Francesco (Canada), <\/span>Kee-Tae Kim (South Korea), Yu Gao (China), Masa Imanishi (Japan), and\u00a0<\/span>Raffaele Rani (Taiwan)\u00a0<\/span><\/p>\n

    \u2013 JCMT program code: M22AL002<\/strong><\/p>\n","protected":false},"excerpt":{"rendered":"

    Determining the role of dense gas in star formation We are observing a large, mass-selected sample of dust-continuum traced, star-forming molecular clouds in HCN J=3-2 and HCO+ J=3-2 with \u2018\u016a\u2019\u016b. This sample includes clouds in the Central Molecular Zone (CMZ), the Inner Galaxy, and the Outer Galaxy. Dense gas is\u2026 Continue reading<\/a><\/p>\n","protected":false},"author":5,"featured_media":0,"parent":3659,"menu_order":0,"comment_status":"closed","ping_status":"closed","template":"","meta":[],"_links":{"self":[{"href":"https:\/\/www.eaobservatory.org\/jcmt\/wp-json\/wp\/v2\/pages\/12322"}],"collection":[{"href":"https:\/\/www.eaobservatory.org\/jcmt\/wp-json\/wp\/v2\/pages"}],"about":[{"href":"https:\/\/www.eaobservatory.org\/jcmt\/wp-json\/wp\/v2\/types\/page"}],"author":[{"embeddable":true,"href":"https:\/\/www.eaobservatory.org\/jcmt\/wp-json\/wp\/v2\/users\/5"}],"replies":[{"embeddable":true,"href":"https:\/\/www.eaobservatory.org\/jcmt\/wp-json\/wp\/v2\/comments?post=12322"}],"version-history":[{"count":7,"href":"https:\/\/www.eaobservatory.org\/jcmt\/wp-json\/wp\/v2\/pages\/12322\/revisions"}],"predecessor-version":[{"id":12395,"href":"https:\/\/www.eaobservatory.org\/jcmt\/wp-json\/wp\/v2\/pages\/12322\/revisions\/12395"}],"up":[{"embeddable":true,"href":"https:\/\/www.eaobservatory.org\/jcmt\/wp-json\/wp\/v2\/pages\/3659"}],"wp:attachment":[{"href":"https:\/\/www.eaobservatory.org\/jcmt\/wp-json\/wp\/v2\/media?parent=12322"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}