Publications (28)
The JWST Early Release Science Program for Direct Observations of Exoplanetary Systems III: Aperture Masking Interferometric Observations of the star HIP 65426 at 3.8 um
Shrishmoy Ray, Steph Sallum, Sasha Hinkley +121
We present aperture masking interferometry (AMI) observations of the star HIP 65426 at as a part of the JWST Direct Imaging Early Release Science (ERS) program obta…
Real-Time Likelihood-Free Inference of Roman Binary Microlensing Events with Amortized Neural Posterior Estimation
Keming Zhang, Joshua S. Bloom, B. Scott Gaudi +3
Fast and automated inference of binary-lens, single-source (2L1S) microlensing events with sampling-based Bayesian algorithms (e.g., Markov Chain Monte Carlo; MCMC) is challenged o…
Predictions of the Nancy Grace Roman Space Telescope Galactic Exoplanet Survey. IV. Lens Mass and Distance Measurements
Sean K. Terry, Etienne Bachelet, Farzaneh Zohrabi +54
As part of the Galactic Bulge Time Domain Survey (GBTDS), the Nancy Grace Roman Galactic Exoplanet Survey (RGES) will use microlensing to discover cold outer planets and free-float…
On the Perturbative Picture and the Chang-Refsdal Lens Approximation for Planetary Microlensing
Keming Zhang
Under the perturbative picture of planetary microlensing, the planet is considered to act as a uniform-shear Chang-Refsdal lens on one of the two images produced by the host star t…
Classification of Periodic Variable Stars with Novel Cyclic-Permutation Invariant Neural Networks
Keming Zhang, Joshua S. Bloom
Neural networks (NNs) have been shown to be competitive against state-of-the-art feature engineering and random forest (RF) classification of periodic variable stars. Although prev…
An Analysis of the Recovery Path of the Consumer Sector in the Post-Pandemic Era
Wenbo Lyu, Jiayi Zhu, Yunan Ding +1
This paper proposes a referencable pattern of the recovery of the consumption sector, a new dimension to observe and evaluate the intrinsic value of the consumption sector, and pro…
GROWTH on S190510g: DECam Observation Planning and Follow-Up of a Distant Binary Neutron Star Merger Candidate
Igor Andreoni, Daniel A. Goldstein, Shreya Anand +23
The first two months of the third Advanced LIGO and Virgo observing run (2019 April-May) showed that distant gravitational wave (GW) events can now be readily detected. Three candi…
Multi-Scale Gaussian-Language Map for Zero-shot Embodied Navigation and Reasoning
Sixian Zhang, Yiyao Wang, Xinhang Song +3
Understanding the geometric and semantic structure of environments is essential for embodied navigation and reasoning. Existing semantic mapping methods trade off between explicit…
GROWTH on S190426c. II. Real-Time Search for a Counterpart to the Probable Neutron Star-Black Hole Merger using an Automated Difference Imaging Pipeline for DECam
Daniel A. Goldstein, Igor Andreoni, Peter E. Nugent +17
The discovery of a transient kilonova following the gravitational-wave event GW170817 highlighted the critical need for coordinated rapid and wide-field observations, inference, an…
GROWTH on S190814bv: Deep Synoptic Limits on the Optical/Near-Infrared Counterpart to a Neutron Star-Black Hole Merger
Igor Andreoni, Daniel A. Goldstein, Mansi M. Kasliwal +49
On 2019 August 14, the Advanced LIGO and Virgo interferometers detected the high-significance gravitational wave (GW) signal S190814bv. The GW data indicated that the event resulte…
The JWST Early Release Science Program for Direct Observations of Exoplanetary Systems I: High Contrast Imaging of the Exoplanet HIP 65426 b from 2-16 m
Aarynn L. Carter, Sasha Hinkley, Jens Kammerer +108
We present JWST Early Release Science (ERS) coronagraphic observations of the super-Jupiter exoplanet, HIP 65426 b, with the Near-Infrared Camera (NIRCam) from 2-5 m, and with…
The Progenitor Star of SN 2023ixf: A Massive Red Supergiant with Enhanced, Episodic Pre-Supernova Mass Loss
Yu-Jing Qin, Keming Zhang, Joshua Bloom +10
We identify the progenitor star of SN 2023ixf in the nearby galaxy Messier 101 using Keck/NIRC2 adaptive optics imaging and pre-explosion HST/ACS images. The supernova position, lo…
The Brown-dwarf Desert Persists as a Mass-ratio Desert around Low-mass Stars
Keming Zhang
Sun-like stars are known to host a paucity of brown dwarf companions at close separations. Direct imaging surveys of intermediate-mass stars have suggested that the brown dwarf des…
The JWST Early Release Science Program for Direct Observations of Exoplanetary Systems V: Do Self-Consistent Atmospheric Models Represent JWST Spectra? A Showcase With VHS 1256 b
Simon Petrus, Niall Whiteford, Polychronis Patapis +119
The unprecedented medium-resolution (R~1500-3500) near- and mid-infrared (1-18um) spectrum provided by JWST for the young (140+/-20Myr) low-mass (12-20MJup) L-T transition (L7) com…
AgentSociety 2: An Integrated Research Environment for Executable Social Science
Jinghua Piao, Jun Zhang, Haoyu Huang +16
AI scientist systems are beginning to automate parts of scientific research, but social science poses a distinct challenge: its objects of inquiry are not merely datasets or labora…
Stellar Spectra Fitting with Amortized Neural Posterior Estimation and nbi
Keming Zhang, Tharindu Jayasinghe, Joshua S. Bloom
Modern surveys often deliver hundreds of thousands of stellar spectra at once, which are fit to spectral models to derive stellar parameters/labels. Therefore, the technique of Amo…
The JWST Early Release Science Program for Direct Observations of Exoplanetary Systems IV: NIRISS Aperture Masking Interferometry Performance and Lessons Learned
Steph Sallum, Shrishmoy Ray, Jens Kammerer +120
We present a performance analysis for the aperture masking interferometry (AMI) mode on board the James Webb Space Telescope Near Infrared Imager and Slitless Spectrograph (JWST/NI…
deepCR: Cosmic Ray Rejection with Deep Learning
Keming Zhang, Joshua S. Bloom
Cosmic ray (CR) identification and replacement are critical components of imaging and spectroscopic reduction pipelines involving solid-state detectors. We present deepCR, a deep l…
KMT-2018-BLG-0029Lb and OGLE-2019-BLG-0960Lb: Mass Measurements for Two Super-Earth Microlensing Planets
Keming Zhang, Sean K. Terry, Joshua S. Bloom +2
KMT-2018-BLG-0029Lb and OGLE-2019-BLG-0960Lb were the lowest mass-ratio microlensing planets at the time of discovery. For both events, microlensing parallax measurements from the…
An Earth-Mass Planet and a Brown Dwarf in Orbit Around a White Dwarf
Keming Zhang, Weicheng Zang, Kareem El-Badry +8
Terrestrial planets born beyond 1-3 AU have been theorized to avoid being engulfed during the red-giant phases of their host stars. Nevertheless, only a few gas-giant planets have…
Portfolio selection models based on interval-valued conditional value at risk (ICVaR) and empirical analysis
Jinping Zhang, Keming Zhang
Risk management is very important for individual investors or companies. There are many ways to measure the risk of investment. Prices of risky assets vary rapidly and randomly due…
nbi: the Astronomer's Package for Neural Posterior Estimation
Keming Zhang, Joshua S. Bloom, Stéfan van der Walt +1
Despite the promise of Neural Posterior Estimation (NPE) methods in astronomy, the adaptation of NPE into the routine inference workflow has been slow. We identify three critical i…
A Ubiquitous Unifying Degeneracy in Two-Body Microlensing Systems
Keming Zhang, B. Scott Gaudi, Joshua S. Bloom
While gravitational microlensing by planetary systems provides unique vistas on the properties of exoplanets, observations of a given 2-body microlensing event can often be interpr…
A Mathematical Treatment of the Offset Microlensing Degeneracy
Keming Zhang, B. Scott Gaudi
The offset microlensing degeneracy, recently proposed by Zhang et al. (2022), has been shown to generalize the close-wide and inner-outer caustic degeneracies into a unified regime…
Automating Inference of Binary Microlensing Events with Neural Density Estimation
Keming Zhang, Joshua S. Bloom, B. Scott Gaudi +3
Automated inference of binary microlensing events with traditional sampling-based algorithms such as MCMC has been hampered by the slowness of the physical forward model and the pa…
TrajRAG: Retrieving Geometric-Semantic Experience for Zero-Shot Object Navigation
Yiyao Wang, Sixian Zhang, Keming Zhang +3
Existing zero-shot Object Goal Navigation (ObjectNav) methods often exploit commonsense knowledge from large language or vision-language models to guide navigation. However, such k…
The JWST Early Release Science Program for Direct Observations of Exoplanetary Systems II: A 1 to 20 Micron Spectrum of the Planetary-Mass Companion VHS 1256-1257 b
Brittany E. Miles, Beth A. Biller, Polychronis Patapis +101
We present the highest fidelity spectrum to date of a planetary-mass object. VHS 1256 b is a 20 M widely separated (8\arcsec, a = 150 au), young, planetary-…
A Shock Flash Breaking Out of a Dusty Red Supergiant
Gaici Li, Maokai Hu, Wenxiong Li +41
Shock breakout emission is light that arises when a shockwave, generated by core-collapse explosion of a massive star, passes through its outer envelope. Hitherto, the earliest det…