I am a graduate student of astrophysics at the Johns Hopkins Univerisity (JHU). I love physics, math, philosophy, classical music, kendo, and anime. Recently, I am reading an astonishing book: A Logical Journey: From Gödel to Philosophy.

Research

I like to view astrophysical problems from both perspectives of physics and statistics in survey data. I am interested in observational cosmology and astrophysics.

New statistics for cosmology and astrophysics

Non-Gaussianities are ubiquitous in astronomical data, but challenging to quantify. The scattering transform provides a brand new vocabulary for describing patterns and textures in non-Gaussian fields (and 1D signals). It borrows ideas from convolutional neural nets (CNNs) but yields robust and interpretable statistics in a deterministic way.
On weak lensing mass maps, I show the scattering transform extracts as much cosmological information as state-of-the-art CNNs and outperforms classic statistics. Read this astrobites blog, or click the figure below to read our paper.

Discoveries about white dwarfs from Gaia satellite

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 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.

While working on white dwarfs, I built a publically available package WD_models in python for transformation between white dwarf photometry and physical properties.

Spectra of meteors

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 connected to a camera lens, 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.

Education

Johns Hopkins University

Department of Physics and Astronomy
2019-present, Ph.D. candidate
2017-2019, M.A.
Advisor: Prof. Brice Ménard

Peking University (北京大学)

Department of Astronomy
2012-2016, B.S.
Advisor: Prof. Eric Peng (彭逸西)

Publications

First author:

Cheng, S., Ting, Y.-S., Ménard, B., & Bruna, J., A new approach to observational cosmology using the scattering transform, 2020, MNRAS, 499, 5902

Cheng, S., Cummings, J. D., Ménard, B., & Toonen, S., Double White Dwarf Merger Products among High-mass White Dwarfs, 2020, ApJ, 891, 160

Cheng, S., Two delays in white dwarf evolution revealed by Gaia, 2019, Proceedings of IAU, 15(S357), 175

Cheng, S., Cummings, J. D., Ménard, B., A Cooling Anomaly of High-mass White Dwarfs, 2019, ApJ, 886, 100

Cheng, S., Cheng, S., Meteor spectral observation with DSLR, normal lens and prism, 2011, JIMO, 39, 39

Others:

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

Bauer, E. B., Schwab, J., Bildsten, L., and Cheng, S., Multi-Gigayear White Dwarf Cooling Delays from Clustering-Enhanced Gravitational Sedimentation, 2020, ApJ, 902, 93

Camisassa, M. E., Althaus, L. G., Torres, S., Córsico, A. H., Cheng, S., Rebassa-Mansergas, A., Forever young white dwarfs: when stellar ageing stops, 2020, arXiv:2008.03028

Chandra, V., Hwang, H.-C., Zakamska, N. L., Cheng, S., A Gravitational Redshift Measurement of the White Dwarf Mass–Radius Relation, 2020, ApJ, 899, 146

Marigo, P., Cummings, J. D., et al., Carbon star formation as seen through the non-monotonic initial–final mass relation, 2020, Nature Astronomy, full text here

Contacts

s.cheng@jhu.edu
+1 443 207 1532
Bloomberg 506
3400 N. Charles St., Johns Hopkins University
Baltimore, MD21218, USA