Dongwon 'DW' Han

Department of Applied Mathematics and Theoretical Physics (DAMTP)

University of Cambridge

CMS, Wilberforce Rd, Cambridge, CB3 0WA

dh689[at]cam.ac.uk

I am a postdoctoral researcher at University of Cambridge with interest in both cosmology and extragalactic astrophysics. One of my current research focus is analyzing the current and upcoming the cosmic microwave background (CMB) data. I worked on many aspects of CMB data analysis, from generating simulations to investigating systematics bias. Recently, I have also been interested in applying Machine Learning in Cosmology and Astrophysics.

news

Dec 1, 2021	a beginning of new blog

selected publications

PRD

Deep learning simulations of the microwave sky

Han, Dongwon, Sehgal, Neelima, and Villaescusa-Navarro, Francisco

Physical Review D Dec 2021

Bib

@article{Han2021b,
  bibtex_show = {true},
  selected = {true},
  author = {Han, Dongwon and Sehgal, Neelima and Villaescusa-Navarro, Francisco},
  doi = {10.1103/PhysRevD.104.123521},
  issue = {12},
  journal = {Physical Review D},
  abbr = {PRD},
  month = dec,
  pages = {123521},
  publisher = {American Physical Society},
  title = {Deep learning simulations of the microwave sky},
  volume = {104},
  url = {https://journals.aps.org/prd/abstract/10.1103/PhysRevD.104.123521},
  year = {2021}
}

arxiv
Mitigating Foreground Bias to the CMB Lensing Power Spectrum for a CMB-HD Survey

Han, Dongwon, and Sehgal, Neelima

arXiv e-prints Dec 2021

Abs Bib

A promising way to measure the distribution of matter on small scales (k 10 hMpc^-1) is to use gravitational lensing of the Cosmic Microwave Background (CMB). CMB-HD, a proposed high-resolution, low-noise millimeter survey over half the sky, can measure the CMB lensing auto spectrum on such small scales enabling measurements that can distinguish between a cold dark matter (CDM) model and alternative models designed to solve problems with CDM on small scales. However, extragalactic foregrounds can bias the CMB lensing auto spectrum if left untreated. We present a foreground mitigation strategy that provides a path to reduce the bias from two of the most dominant foregrounds, the thermal Sunyaev-Zel’dovich effect (tSZ) and the Cosmic Infrared Background (CIB). Given the level of realism included in our analysis, we find that the tSZ alone and the CIB alone bias the lensing auto spectrum by 0.6 sigma and 1.1 sigma respectively, in the lensing multipole range of L in [5000,20000] for a CMB-HD survey; combined these foregrounds yield a bias of only 1.3 sigma. Including these foregrounds, we also find that a CMB-HD survey can distinguish between a CDM model and a 10^-22 eV FDM model at the 5 sigma level. These results provide an important step in demonstrating that foreground contamination can be sufficiently reduced to enable a robust measurement of the small-scale matter power spectrum with CMB-HD.
@article{Han2021c, bibtex_show = {true}, selected = {true}, author = {Han, Dongwon and Sehgal, Neelima}, month = dec, journal = {arXiv e-prints}, abbr = {arxiv}, title = {Mitigating Foreground Bias to the CMB Lensing Power Spectrum for a CMB-HD Survey}, url = {https://arxiv.org/abs/2112.02109v1}, year = {2021} }
JCAP
The Atacama Cosmology Telescope: delensed power spectra and parameters

Han, Dongwon, Sehgal, Neelima, MacInnis, Amanda, Engelen, Alexander, Sherwin, Blake D., Madhavacheril, Mathew S., Aiola, Simone, Battaglia, Nicholas, Beall, James A., Becker, Daniel T., Calabrese, Erminia, Choi, Steve K., Darwish, Omar, Denison, Edward V., Devlin, Mark J., Dunkley, Jo, Ferraro, Simone, Fox, Anna E., Hasselfield, Matthew, Hill, J. Colin, Hilton, Gene C., Hilton, Matt, Hložek, Renée, Hubmayr, Johannes, Hughes, John P., Kosowsky, Arthur, Lanen, Jeff Van, Louis, Thibaut, Moodley, Kavilan, Naess, Sigurd, Namikawa, Toshiya, Nati, Federico, Nibarger, John P., Niemack, Michael D., Page, Lyman A., Partridge, Bruce, Qu, Frank J., Schillaci, Alessandro, Spergel, David N., Staggs, Suzanne, Storer, Emilie, and Wollack, Edward J.

Journal of Cosmology and Astroparticle Physics Jan 2021

Bib
@article{Han2021a, bibtex_show = {true}, selected = {true}, author = {Han, Dongwon and Sehgal, Neelima and MacInnis, Amanda and van Engelen, Alexander and Sherwin, Blake D. and Madhavacheril, Mathew S. and Aiola, Simone and Battaglia, Nicholas and Beall, James A. and Becker, Daniel T. and Calabrese, Erminia and Choi, Steve K. and Darwish, Omar and Denison, Edward V. and Devlin, Mark J. and Dunkley, Jo and Ferraro, Simone and Fox, Anna E. and Hasselfield, Matthew and Hill, J. Colin and Hilton, Gene C. and Hilton, Matt and Hložek, Renée and Hubmayr, Johannes and Hughes, John P. and Kosowsky, Arthur and Lanen, Jeff Van and Louis, Thibaut and Moodley, Kavilan and Naess, Sigurd and Namikawa, Toshiya and Nati, Federico and Nibarger, John P. and Niemack, Michael D. and Page, Lyman A. and Partridge, Bruce and Qu, Frank J. and Schillaci, Alessandro and Spergel, David N. and Staggs, Suzanne and Storer, Emilie and Wollack, Edward J.}, doi = {10.1088/1475-7516/2021/01/031}, issn = {1475-7516}, issue = {01}, journal = {Journal of Cosmology and Astroparticle Physics}, abbr = {JCAP}, keywords = {Astrophysics - Cosmology and Nongalactic Astrophysics,High Energy Physics - Phenomenology}, month = jan, pages = {031-031}, title = {The Atacama Cosmology Telescope: delensed power spectra and parameters}, volume = {2021}, url = {https://iopscience.iop.org/article/10.1088/1475-7516/2021/01/031}, year = {2021} }