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Research Topics

The astronomy group at UC Riverside now has five astronomy faculty members, ~5 postdocs, and ~20 graduate students.  The group is focused primarily on extragalactic astronomy and is part of the newly-formed Southern California Center for Galaxy Evolution.  Below is a summary of the various research topics.

Galaxy Evolution

Cosmic Dawn and Reionization

Galaxies began to form rapidly within the first billion years, with profound consequences on the intergalactic medium.  Several groups at UC Riverside are involved in the largest surveys ever conducted with the Hubble and Spitzer Space Telescope and the Keck Observatory.  We are determining how quickly star formation began and how this star formation ionized all of the hydrogen in the intergalactic medium.

A Census of Star Formation

Most of the stars in the universe formed 7-11 billion years ago.  We are quantifying the global rate of star formation at this critical epoch, and understanding where and why the star formation happened.

Dust Extinction and the Infrared Background

Much of the light we observe from distant galaxies has been absorbed by dust within those galaxies.  With ultraviolet and infrared measurements from the ground and in space, we are determining how to correct for the absorption to better determine the intrinsic properties of galaxies.

As the dust absorbs light, it heats up and emits infrared radiation.  Fully one half of all light from galaxies is emitted in the infrared.  With the Spitzer and Herschel Space Telescopes, we are measuring galaxies’ infrared luminosity to better understand their star formation and black hole accretion rates.

Galaxy Clusters and Cosmology

Galaxy Formation in High Density Environments

Rich Clusters as Lenses

The extreme gravitation fields of galaxy clusters can bend light from background galaxies, acting as magnifying glasses for us.  Because of this we're able to see fainter galaxies than would otherwise be possible.  We are using these natural magnifying glasses to study, in exquisite detail, the properties of extremely faint galaxies in the distant universe.

Active Galaxies

Black Hole Growth in the Early Universe

Recent discoveries suggest that very massive (billion solar mass) black holes were able to form in the early universe.  Several groups at UCR are conducting searches for black holes that are actively growing during these early epochs.  The number of these black holes, and their spatial distribution has profound effects on galaxy formation and the temperature and ionization state of the intergalactic medium.

Accretion Triggers and the Starburst/AGN Connection

The mass of a galaxy's central black hole is correlated with the mass of the galaxy, though their sizes are dramatically different in scale.  It begs the question, what triggers star formation and what triggers black hole growth and are they related?  We are studying the properties of galaxies with and without black hole accretion, and with and without star formation, to better understand the mechanisms which trigger these processes, and how tightly they're related.

AGN Feedback

Actively accreting black holes expel enormous amounts of light and mechanical energy.  We are investigating the effects of this energy on the surrounding galaxy and beyond.