Dust-free Insight into the Obscured Cosmic Accretion History and Modes of Galaxy Assembly

2017 Fiscal Year Final Research Report

• Project/Area Number: 15K17604
• Research Category: Grant-in-Aid for Young Scientists (B)
• Allocation Type: Multi-year Fund
• Research Field: Astronomy
• Research Institution: The University of Tokyo
• Principal Investigator: RUJOPAKARN WIPHU 東京大学, カブリ数物連携宇宙研究機構, 客員科学研究員 (60731776)
• Project Period (FY): 2015-04-01 – 2018-03-31
• Keywords: galaxy evolution / galaxy assembly / star formation / active galactic nuclei / SF - AGN coevolution

Outline of Final Research Achievements

The support from this program has enabled successful analysis and dissemination of results from the most sensitive astronomical survey at radio frequencies ever conducted. We used the Very Large Array radio observatory to conduct 2 - 8 GHz imaging of the Hubble Ultra-Deep Field at the sensitivities required to capture star-forming galaxies at z ~ 1-3, the peak epoch of galaxy assembly. We found that (1) the typical morphology of star formation (SF) in rapidly assembling galaxies at redshift z ~ 2 to be disk-wide, consistent with the scenario that galaxies assemble most of their stellar mass via accretion of cold gas, which leads to gas-rich, unstable disks and in-situ disk-wide star formation; and that (2) the active galactic nuclei (AGN) and SF are co-spatial at z ~ 3, consistent with a picture of in-situ galactic bulge and MBH growth. The program has spurred multiple new observing campaigns to definitively characterize the SF morphologies and the co-spatial nature of SF and AGN.

Free Research Field

天文学