Galaxies & ISM

Galaxies are gravitationally bound assemblies of stars, the interstellar medium (or ISM, which is the gas and dust between the stars), stellar remnants, black holes, and dark matter. 

Research Highlights

AGN feedback
Simulation of an AGN jet in a galaxy cluster

AGN Feedback in Galaxy Clusters

Galaxy cluster cores can be significantly heated and stirred by jets from accreting black holes in active galactic nuclei (AGN). We develop subgrid models to incorporate these effects realistically into cosmological hydrodynamics simulations of galaxy cluster formation.

Links to research groups and facilities:  Paul Ricker


Lensed Galaxy
A gravitationally-lensed galaxy

High-redshift gravitationally-lensed galaxies

The South Pole Telescope conducted a 2500 square degree cosmological survey and systematically identified a large number (>100) of high-redshift strongly gravitationally lensed starburst galaxies. We have completed a unique spectroscopic redshift survey with ALMA, targeting carbon monoxide line emission in these sources. We have obtained spectroscopic redshifts for 82 sources from 1.8 < z < 6.9, with a median of z=3.9. This sample comprises 70% of the total spectroscopically confirmed dusty galaxies at z>4 and extends into the epoch of re-ionization. We are systematically measuring low-J CO, [CII], and [NII] for these sources with ATCA, APEX, and ALMA, making this the largest and most well-studied samples of high-redshift starburst galaxies. We are also using the lensing magnification to study these sources at the highest possible resolution with CO, [CII], and H2O. We are undertaking a comprehensive and systematic followup campaign to use these "cosmic magnifying glasses" to study the physical conditions and chemical evolution of the dust-obscured universe in unprecedented detail. Two of these sources were recently selected to be among the first objects targeted with NASA’s James Webb Space Telescope (JWST) as part of the Early Release Science (ERS) science observations.

Links to research groups and facilities: Joaquin Vieira, ALMA, SPT, JWST


CO image of the A439 cloud in the LMC
CO image of the A439 cloud in the LMC

Molecular Clouds in Nearby Galaxies

Stars are born in giant molecular clouds of dense gas, but how the physical characteristics of these clouds relate to their ability to form stars is still poorly understood.  By observing these clouds in nearby galaxies, we can study them in a wider variety of environments than are found in the vicinity of the Sun.  Prof. Wong's group uses radio telescopes such as ALMA to map the gas in these clouds in nearby galaxies, including the Magellanic Clouds.  We can then compare these maps with images of stars, dust, and ionized gas obtained at optical and infrared wavelengths.

Links to research groups and facilities: Tony Wong, ALMA



Faculty Interested in Galaxies and ISM

Name Research Interests
Cosmology, extragalactic astronomy, machine and deep learning, especially in large scale structure, galaxy formation and evolution, environmental dependence of galaxy properties and photometric redshift estimation.
Cosmology, Nuclear and Particle Astrophysics; Nucleosynthesis; Dark Matter; Cosmic-ray, Gamma-ray, and Neutrino Astrophysics; Supernovae; Astrobiology
Survey Science; Galaxies; ISM; LMC and SMC
Astrochemistry; Laboratory Spectroscopy; ISM; Diffuse Interstellar Bands
Observational Cosmology; Clusters of Galaxies and Sunyaev-Zeldovich Effect; Large Surveys; Data Analysis Pipelines for Surveys; Algorithms for Data Mining; Galaxy Formation and Evolution
Cosmic Magnetic Fields; Formulation of Theory of Star Formation Accounting for Role of Magnetic Fields; Astrophysical Analytical and Numerical Magnetohydrodynamics; Diffuse Matter Astrophysics
Observational Cosmology; Quasars and Active Galactic Nuclei; Galaxy Formation and Evolution; Surveys and Time-Domain Science
Cosmology; Extragalactic Surveys; Galaxy Evolution; Instrumentation; Observation
Molecular Clouds; Star Formation in Nearby Galaxies; Evolution of Disk Galaxies