Research

I study astrophysics and cosmology. My main interests lie in the Epoch of Reionization
and, more recently, Milky Way dynamics.

 
 

The radial action Jr vs. age, showing the correlation with age but large scatter in that correlation.

Actions are weak stellar age indicators in the Milky Way disk

with Melissa Ness (Columbia University, CCA) and Megan Bedell (CCA)

Over time, stellar orbits are expected to become more non-circular and non-planar, described by their orbit's actions. Using two samples of stars with well-determined ages, we quantify the action-age relations. We demonstrate a correlation, but the spread on this relation is too large for actions to be used to infer stellar ages.

Animated versions of Figs. 5 & 6 available here.

ApJ Accepted
arXiv: 1807.05986

 

The 21 cm bias factor, as extracted using the cross-spectrum and our bispectra.

Extracting bias using the cross-bispectrum: An EoR and 21 cm-[CII]-[CII] case study

with Adam Lidz (University of Pennsylvania)

The main obstacle to 21 cm observation of the Epoch of Reionization are large foregrounds. One proposed cross-check is to cross-correlate 21 cm observations from z~6-9 with intensity mapping surveys of, e.g., the [CII] line at the same redshifts. The downside of this approach is that you have to know about the evolution in the [CII] line in order to extract information about the EoR. We propose a similar cross-check that avoids this problem.

ApJ Accepted
arXiv: 1806.02796

 

 

Dynemicin A undergoing two modes of intercalation, compact (left) and expansive (right).

Internal abstraction of dynemicin A: An MD approach

with Bill Miller, III (Truman State University) and Carol Parish (University of Richmond)

Dynemicin A is an anti-tumor drug which kills cancerous cells by binding to and cutting DNA. It is thought to work by inserting into the minor groove of DNA and then undergoing a cyclization process before abstracting a hydrogen atom from the DNA backbone. Intercalation, or inserting between two base pairs as opposed to in the minor groove, is thought to stop the activity of dynemicin A. We provide evidence that dynemicin A may abstract a hydrogen atom from itself first and then subsequently abstract a hydrogen atom from the DNA backbone.

Beane, A.; Miller, III, B.; Parish, C. J. Mol. Graph. Model. 201774, 251.
Available online.