University of Minnesota
School of Physics & Astronomy

Physics and Astronomy Calendar

Monday, December 2nd 2019
12:15 pm:
Speaker: Vihang Mehta, UMN
Subject: Clump Scout: understanding the role of massive star-forming clumps in galaxies

There is growing evidence suggestive of a substantial evolution in the dominant mode of star-formation on a galactic scale from the high-redshift to the local galaxies, as observations reveal decreasing cosmic star-formation rate, evolving galactic morphologies, and decreasing galactic gas fractions. From Hubble observations, massive star-forming "clumps" embedded within chaotic, irregular morphologies seem to be common in the typical star-forming galaxies at the cosmic high-noon (the peak of cosmic star-formation at z~2). This is in stark contrast to the local star-forming galaxies which instead have thin, uniform morphologies and the massive clumps are considerably rarer. Determining the mechanisms that drive this evolution in the star-formation activity in galaxies still remains to be fully understood.

In order to shed insight on this mystery, we are conducting a citizen-scientist project, Clump Scout (, to identify the rare massive star-forming clumps in local star-forming galaxies in the Sloan Digital Sky Survey (SDSS). The main goal of this project is to assemble a statistically significant sample of clumps in the local universe and compare their properties to those identified in the high-redshift galaxies from various Hubble surveys, in order to ultimately understand the role of these clumps play in the growth and evolution of galaxies. In this talk, I will briefly provide background on massive star-forming clumps and outline the on-going efforts to identify and study these in galaxies. I will also highlight the motivation for the Clump Scout project as well as share preliminary insights from the initial set of volunteer classifications along with its future prospects.

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