University of Connecticut

Events Calendar

Astronomy Seminar

Wednesday, October 18, 2017
12:00pm – 1:00pm

Storrs Campus

This week the astronomy seminar series features the undergraduate research projects of two students, Sam Cutler and Amelia Henkel. Sam, a junior undergraduate physics majors, will discuss results from his research internship at the University of Copenhagen this past summer. Amelia, a senior undergraduate physics and human rights major, will present results from her REU, University of Texas, Rio Grande Valley.

Sam Cutler

“Examining High Redshift Rotation Curves and Dark Matter Profiles Outside the Local Universe”

Examination of galactic rotation curves in the local universe has yielded evidence of both cusp and core type dark matter profiles. We present one of the first studies of a galactic rotation curve for a distant gravitationally-lensed massive, dusty star-forming galaxy, CL2244-1, with a spectroscopic redshift 1.77. Using VLT/XSHOOTER spectroscopy, we perform a 2D spectral analysis of the H-alpha emission. With this rotation curve, we fit a dark matter density profile and determine the functional form of the profile (cusp or core). Predictions from comparing the shape of the rotation curve of CL2244-1 to that of M33 and other galaxies in the local universe suggest that the dark matter profile of CL2244-1 is best represented by a cuspy profile. Though this cuspy profile supports the cold dark matter cosmological model, we cannot rule out self-interacting dark matter, whose interactions may not have had time to shift the density profile to a core at such early times.

Amelia Henkel

“Simulating Pulsar Signals to Search for Low-Frequency Gravitational Waves”

Gravitational waves, a product of Einstein’s theory of general relativity, have become an important tool for understanding how gravity behaves at some of the largest scales. The merging of supermassive black holes in the centers of galaxies provides information about the most extreme gravity fields in the Universe but such events are unobservable by Earth-based observatories due to their immensely low frequencies (f∼10^−7 − 10^-9 Hz). Pulsar timing arrays (PTAs) exploit the regularity of millisecond pulsars (MSPs) by searching for minute changes in their signals’ times of arrival (TOAs) and are sensitive to supermassive black hole binaries (SMBHB). Due to a series of effects on the pulsar signals as they traverse the galaxy, it often becomes difficult to precisely measure their TOAs. To combat this we are developing a pulsar signal simulator to individually characterize each effect on the signal and verify how the effect manifests in the observed signals. In this talk, I will discuss the simulation of signal dispersion due to the interstellar medium (ISM) as well as simulations of gravitational waves.


Prof. Whitaker

Physics Department (primary)

Control Panel