Welcome!
I'm a PhD candidate in Astronomy & Astrophysics
at the University of Chicago.

The background here is a photo I took in an observing trip to Chile, showing the Magellan 6.5-m telescopes at the Las Campanas Observatory.

Research

My research focuses on observations of the diffuse circumgalactic medium (CGM) -- the outermost envelopes of galaxies. I seek to better understand the dynamical state of the CGM, and its connection to the star-formation/AGN activities of galaxies and the cosmic baryon cycle in general. My work heavily relies on data obtained by wide-field, integral-field spectrographs (e.g., VLT/MUSE), together with photometric and spectroscopic data from several different telescope such as the Hubble Space Telescope and the Magellan Telescopes. I also have extensive experience in lens modeling of strong gravitational lensing clusters, with both parametric and free-form methods. My PhD advisor is Prof. Hsiao-Wen Chen.

Here is the ADS link to my publications. Below you can find a list of my recent papers.

Empirical constraints on the turbulence in QSO host nebulae from velocity structure function measurements
Chen et al. 2022, MNRAS submitted.
QSO host nebulae turbulence

Chen et al. 2022, MNRAS submitted: In this paper we use velocity structure functions to constrain the turbulence in extended QSO host nebulae revealed by [OII] and [OIII] emission lines. One source shows spectacular agreement with the expectation from Kolmogorov turbulence!
You can also watch me giving a summary about the key results from this paper in this short video, posted on the Galactic Atmospheres online forum.

Resolved galactic superwinds reconstructed around their host galaxies at z > 3
Chen et al. 2021, MNRAS.
supergalactic winds at z>3 seen in Lyman-alpha

Chen et al. 2021, MNRAS: In this paper we presented a detailed analysis of two giant Lyman-alpha arcs at z > 3 strongly lensed by a massive cluster. Using spatially-resolved line profiles revealed in deep MUSE observations, we identified these arcs as supergalactic winds driven by nearby star-forming galaxies.
You can also watch me giving a summary about the key results from this paper in this short video, posted as part of the KITP workshop "Fundamentals of Gaseous Halos".

Geometric Support for Dark Matter by an Unaligned Einstein Ring in A3827
Chen et al. 2020, ApJ.
Resolved Einstein ring

Chen et al. 2020, ApJ: Using a super cool cluster lensing system in the nearby Universe, we demonstrated that the geometric configuration of the lensing effect here requires the presence of dark matter, hence presenting a two-dimensional challenge to alternative gravity theories.
There is also an Astrobites article giving a very nice summary of this paper.

A Likely Supermassive Black Hole Revealed by Its Einstein Radius in Hubble Frontier Fields Images
Chen et al. 2018, ApJ.
Multiply-lensed images of a background spiral galaxy

Chen et al. 2018, ApJ: Here we directly estimate the mass of a supermassive black hole (SMBH) using a lensed image near the center of a brightest cluster galaxy at z=0.5, when the Universe was only half of its current age. The mass of the SMBH turns out to be ~1000 times more massive than the SMBH at the center of the Milky Way!

I'm also a member of the Cosmic Ultraviolet Baryon Survey (CUBS) collaboration (PI: Hsiao-Wen Chen). I reduced the VLT/MUSE IFU data for all 15 CUBS QSO fields, and have been actively involved in projects analyzing CGM emission detected in the 3D IFU datacubes. So far CUBS have published five papers, with me as a primary contributing author in all of them.

Currently I'm wrapping up a paper focusing on the velocity structure function measurements of extended optical nebulae illuminated by QSOs, aiming to find evidence (or lack thereof) for established turbulence in the line-emitting CGM. I've also tremendously enjoyed working with IFU data, and am always happy to chat about data reduction/analyses, line feature fittings, machine learning (especially deep neural networks), strong lensing, and any combination/synergy of these topics.

About Me

Outside of my research life, I enjoy traveling, hiking, meeting new people, discovering new food and drinks, and just being around friends in general. I've had many hobbies involving music (piano and drum), painting (watercolor and fabric painting) and crafting (knitting and crochet). Though none of them stuck with me in the long term, they had sparked so much joy in my life (oh did I forget to mention the brief Marie Kondo phase I had :P), and I'm wondering what I should do next just while typing this. During the pandemic I adopted my little cat Jenny, who alternates between being feisty and cuddly, and I love her deeply.

I grew up in Guizhou province in southwest China, a place relatively underdeveloped in terms of economics and education, but with gorgeous mountainous landscapes and rich cultural heritage from multiple ethnic minorities. I studied at the University of Hong Kong (HKU) and graduated with a B.Sc. in physics and an M.Phil. in astronomy. Growing up with little access to quality education, I feel extremely grateful for the chains of lucky events and good mentors that allowed me to reach beyond my limitations. My experiences of living in mainland China, Hong Kong and the US made me appreciate the value of diversity and inclusion, which can only be built upon a foundation of empathy and everyone's willingness to always approach the unknowns with an open mind.

I once wanted to be a clinical psychologist and was working towards a master's degree in psychology, but decided to drop out halfway to go back to pursuing graduate studies in astrophysics. Although becoming a frontier mental health professional is not my career priority right now, I strongly believe in the importance of mental health awareness and the destigmatization of mental illnesses.

Contact

mandychen@astro.uchicago.edu

GitHub: github.com/mandychen-astro
LinkedIn: linkedin.com/in/cuncheng-mandy-chen

Department of Astronomy and Astrophysics
The University of Chicago
William Eckhardt Research Center, room 526
5640 South Ellis Avenue
Chicago, Illinois 60637