I am a postdoc researcher at the Johns Hopkins Univerisity (JHU) and now visiting the École Normale Supérieure, Paris (ENS). I just got my Ph.D. in astrophysics this summer at JHU. I love physics, math, philosophy, classical music, kendo, and anime.
I am interested in using statistical analysis to understand our Universe. My interests range from observational cosmology to stellar physics and planets. My work led to the discovery of special stars that shine out of gravitational sedimentation and the cosmological applications of a new statistic that borrows ideas from convolutional neural networks.
Textures and patterns are ubiquitous in astronomical data but challenging to quantify. The scattering transform provides a new powerful statistic for these features. It borrows ideas from convolutional neural nets (CNNs), but shares advantages of traditional statistics. In my recent papers (, , ), I discussed in depth how to intuitively understand this new statistic which is unfamiliar to most physicists, and I showed that on weak lensing mass maps it outperforms classic statistics and is on a par with CNNs. The first paper won an award of astrostatistics and was reported by this astrobites blog.
To advocate the use of the scattering transform, I also wrote a publicly available module
ST.py based on pytorch, which can implement 1D and 2D scattering transform in a fast and transparent way.
I also work on white dwarfs, the destiny of most stars in the universe. Using data from the Gaia space mission, I discovered a new population of white dwarfs that cool extremely slowly and some others that are merger products. My work has led to two papers (click the figures below), one of which was highlighted by astrobites and AAS Nova and considered a major discovery in Gaia data.
To make white dwarf research easier, I also built a publically available package
WD_models in python for transformation between white dwarf photometry and physical properties.
In high school, my twin brother (who is studying philosophy now) and I found an efficient way to take spectra of meteors with digital camera. We designed a prism device that can screw in front of a lens. We ordered several from a factory, and sold them to other amateurs of astronomy. Shown below is one spectrum of the Geminid meteor shower, taken in 2010. We have made a new batch of such prism devices with a cost of less than 200 dollars each. If you are interested, please contact us or buy it here!
The Centre for Sciences of Data
2021- now, visiting fellow
Advisor: Prof. Stéphane Mallat
Department of Astronomy
Advisor: Prof. Eric Peng (彭逸西)
Cheng, S., Two delays in white dwarf evolution revealed by Gaia, 2019, Proceedings of IAU, 15(S357), 175
Lu, C. X., Schlaufman, K. C., Cheng, S., An Increase in Small-planet Occurrence with Metallicity for Late-type Dwarf Stars in the Kepler Field and Its Implications for Planet Formation, 2020, AJ, 160, 253
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Baltimore, MD21218, USA