Research and publications

I am a sixth year Ph.D. candidate at Rutgers working with Andrew Baker. I use observations to study the interstellar medium and star formation in order to better understand galaxy evolution. A list of my refereed publications appears below:

  1. "The Star-Forming Interstellar Medium of Lyman Break Galaxy Analogs,"
    Wu, J. F., Baker, A. J., Heckman, T.M., Hicks, E. K. S., Lutz, D., Tacconi, L. J., 2019, ApJ, submitted.
  2. "Using convolutional neural networks to predict galaxy metallicity from three-color images,"
    Wu, J. F., Boada, S., 2019, MNRAS, 484, 4683. [ads]
  3. "Herschel and ALMA Observations of Massive SZE-selected Clusters,"
    Wu, J. F., Aguirre, P., Baker, A. J., Devlin, M. J., Hilton, M., Hughes, J. P., Infante, L., Lindner R. R., Sifón, C., 2018, ApJ, 853, 195. [ads]
  4. "Galaxy Candidates at z ~ 10 in Archival Data from the Brightest of Reionizing Galaxies (BORG[z8]) Survey,"
    Bernard, S. R., Carrasco, D., Trenti, M., Oesch, P. A., Wu, J. F., Bradley, L. D., Schmidt, K. B., Bouwens, R. J., Calvi, V., Mason, C. A., Stiavelli, M., Treu, T., 2016, ApJ, 827, 76. [ads]

An SDSS image cutout, along with its observed and convolutional neural network-predicted metallicity.

Machine learning

Deep convolutional neural networks have performed remarkably well in image classification or regression tasks. In a recent paper, we have trained a convolutional neural network to predict the gas-phase oxygen abundance, or metallicity, of a galaxy using only optical gri imaging. Training and testing were done using photometric and spectroscopic observations from the Sloan Digital Sky Survey.

Image: A typical SDSS galaxy along with its metallicity measured from spectral line ratios (Ztrue) and metallicity predicted by our trained neural network (Zpred). See our paper for more details.

Nearby analogs of Lyman break galaxies (LBGs)

I have been using integral field spectroscopy at near-infrared wavelengths to characterize kinematics, dust, ionization properties, and warm molecular hydrogen in a sample of compact, UV-bright, star-forming galaxies that strongly resemble high-redshift LBGs.

Image: H2/Paα emission line ratios (pink) and ionized gas (white contours) shown for J1434, a LBG analog system. The companion galaxy to the northwest is characterized by unusually intense H2 radiation from massive, newly formed stars, while the central galaxy is bright in Paα but not H2 emission. For more, be on the lookout for J. F. Wu et al., (2019, ApJ, submitted).

An image of the massive mergiving cluster, El Gordo.

Galaxies in clusters

I investigate massive galaxy clusters detected via the Sunyaev-Zel'dovich effect by the Atacama Cosmology Telescope (ACT). El Gordo, a massive cluster merger at z = 0.87, is depicted in Hubble Space Telescope imaging with overlaid mass density profiles in blue and X-ray emission in pink. We have studied galaxies in massive clusters by using observations from Herschel and the Atacama Large Millimeter/submillimeter Array (ALMA) to study their dust, cool gas, and star formation properties. See our paper for more details.

Image credit: NASA, ESA, Jee et al.

Life, et cetera.

I like coffee, snowboarding, data visualization, gardening, radio interferometry, and Oxford commas. At Rutgers, I have served on the Graduate Student Organization (GSO), organized the Student Seminars in Physics And Astronomy (SSPAR), and started not just one but two coffee clubs. Check out some of the panels below to read more about a few of my interests.

Click to see some more plots!

Python data visualization

I mostly code in Python, which you can see in my side projects hosted on Github. Shown above is a visualization of the RESOLVE/ECO dataset using matplotlib and Seaborn.

My Github page
The picture is way too fancy for us. But we do have free pizza!


Student Seminars in Physics and Astronomy Research (SSPAR) is a lecture series given by students to other students. SSPAR provides a semi-professional setting for students to present their research and practice public speaking.

Learn more about SSPAR
A view from Castel Gandolfo.

Vatican Observatory Summer School

In 2014, I had the opportunity to work on astronomy research at the Vatican Observatory. I took this photograph in Albano, Italy.

Rutgers press release