170 citations · 1.4k across the 31 of their papers we have counts for
32 papers
The North/South Asymmetry of the Galaxy: Possible Connection to the Vertical Phase Space Snail
Rui Guo, Juntai Shen, Zhao-yu Li +2
The Galaxy is found to be in disequilibrium based on recent findings of the North/South (N/S) asymmetry and the phase mixing signatures, such as a phase spiral (snail) structure in…
The Flattening Metallicity Gradient in the Milky Way's Thin Disk
John J. Vickers, Juntai Shen, Zhao-Yu Li
We calculate the ages, orbits and phase-space coordinates for a sample of 4 million LAMOST and Gaia stars. The ages are crossmatched and compared with values from two other p…
A LAMOST BHB Catalog and Kinematics Therein I: Catalog and Halo Properties
John J. Vickers, Zhao-Yu Li, Martin C. Smith +1
We collect a sample of stars observed both in LAMOST and Gaia which have colors implying a temperature hotter than 7000 K. We train a machine learning algorithm on LAMOST spectrosc…
Understanding the velocity distribution of the Galactic Bulge with APOGEE and Gaia
Yingying Zhou, Zhao-Yu Li, Iulia Simion +5
We revisit the stellar velocity distribution in the Galactic bulge/bar region with APOGEE DR16 and {\it Gaia} DR2, focusing in particular on the possible high-velocity (HV) peaks a…
Vertical Phase Mixing across the Galactic Disk
Zhao-Yu Li
By combining the {\it LAMOST} and {\it Gaia} data, we investigate the vertical phase mixing across the Galactic disk. Our results confirm the existence of the phase space snail she…
Optimal Emergency Frequency Control Based on Coordinated Droop in Multi-Infeed Hybrid AC-DC System
Ye Liu, Chen Shen
In multi-infeed hybrid AC-DC (MIDC) systems, the asynchronous interconnection between regional grids, the complicated system dynamics and possible cascading failures have an enormo…
The Carnegie-Irvine Galaxy Survey. IX. Classification of Bulge Types and Statistical Properties of Pseudo Bulges
Hua Gao, Luis C. Ho, Aaron J. Barth +1
We study the statistical properties of 320 bulges of disk galaxies in the Carnegie-Irvine Galaxy Survey, using robust structural parameters of galaxies derived from image fitting.…
Testing the Tremaine-Weinberg Method Applied to Integral-field Spectroscopic Data Using a Simulated Barred Galaxy
Yanfei Zou, Juntai Shen, Martin Bureau +1
Tremaine and Weinberg (TW) proposed a conceptually simple procedure relying on long-slit spectroscopy to measure the pattern speeds of bars () in disk galaxies. Using a…
Dissecting the Phase Space Snail Shell
Zhao-Yu Li, Juntai Shen
The on-going vertical phase mixing, manifesting itself as a snail shell in the phase space, has been discovered with the Gaia DR2 data. To better understand the origin an…
The Carnegie-Irvine Galaxy Survey. VIII. Demographics of Bulges along the Hubble Sequence
Hua Gao, Luis C. Ho, Aaron J. Barth +1
We present multi-component decomposition of high-quality -band images of 312 disk galaxies from the Carnegie-Irvine Galaxy Survey. In addition to bulges and disks, we successful…
The Carnegie-Irvine Galaxy Survey. VI. Quantifying Spiral Structure
Si-Yue Yu, Luis C. Ho, Aaron J. Barth +1
The Carnegie-Irvine Galaxy Survey provides high-quality broad-band optical images of a large sample of nearby galaxies for detailed study of their structure. To probe the physical…
The Carnegie-Irvine Galaxy Survey. VII. Constraints on the Origin of S0 Galaxies from Their Photometric Structure
Hua Gao, Luis C. Ho, Aaron J. Barth +1
Using high-quality optical images from the Carnegie-Irvine Galaxy Survey, we perform multi-component decompositions of S0 galaxies to derive accurate structural parameters to const…
Shape of LOSVD\lowercase{s} in barred disks: Implications for future IFU surveys
Zhao-Yu Li, Juntai Shen, Martin Bureau +3
The shape of LOSVDs (line-of-sight velocity distributions) carries important information about the internal dynamics of galaxies. The skewness of LOSVDs represents their asymmetric…
Chemical abundances and ages of the bulge stars in APOGEE high-velocity peaks
Yingying Zhou, Juntai Shen, Chao Liu +17
A cold high-velocity (HV, 200 km/s) peak was first reported in several Galactic bulge fields based on the APOGEE commissioning observations. Both the existence and the natur…
Orbital decomposition of CALIFA spiral galaxies
Ling Zhu, Remco van den Bosch, Glenn van de Ven +9
Schwarzschild orbit-based dynamical models are widely used to uncover the internal dynamics of early-type galaxies and globular clusters. Here we present for the first time the Sch…
The Local Volume HI Survey: star formation properties
Jing Wang, Baerbel S. Koribalski, Tom H. Jarrett +12
We built a multi-wavelength dataset for galaxies from the Local Volume HI Survey (LVHIS), which comprises 82 galaxies. We also select a sub-sample of ten large galaxies for investi…
A parametric description of the 3D structure of the Galactic Bar/Bulge using the VVV survey
Iulia T. Simion, Vasily Belokurov, Mike Irwin +5
We study the structure of the inner Milky Way using the latest data release of the Vista Variables in Via Lactea (VVV) survey. The VVV is a deep near-infrared, multi-colour photome…
The Carnegie-Irvine Galaxy Survey. V. Statistical study of bars and buckled bars
Zhao-Yu Li, Luis C. Ho, Aaron J. Barth
Simulations have shown that bars are subject to a vertical buckling instability that transforms thin bars into boxy or peanut-shaped structures, but the physical conditions necessa…
The local spiral arm in the LAMOST-Gaia common stars?
Chao Liu, You-Gang Wang, Juntai Shen +7
Using the LAMOST-Gaia common stars, we demonstrate that the in-plane velocity field for the nearby young stars are significantly different from that for the old ones. For the young…
The Carnegie-Irvine Galaxy Survey. IV. A Method to Determine the Average Mass Ratio of Mergers That Built Massive Elliptical Galaxies
Song Huang, Luis C. Ho, Chien Y. Peng +2
Many recent observations and numerical simulations suggest that nearby massive, early-type galaxies were formed through a "two-phase" process. In the proposed second phase, the ext…
Mapping the Three-Dimensional "X-Shaped Structure" in Models of the Galactic Bulge
Zhao-Yu Li, Juntai Shen
Numerical simulations have shown that the X-shaped structure in the Milky Way bulge can naturally arise from the bar instability and buckling instability. To understand the influen…
Theoretical Models of the Galactic Bulge
Juntai Shen, Zhao-Yu Li
Near infrared images from the COBE satellite presented the first clear evidence that our Milky Way galaxy contains a boxy shaped bulge. Recent years have witnessed a gradual paradi…
Kinematics of the X-shaped Milky Way Bulge: Expectations from a Self-consistent N-body Model
Yujing Qin, Juntai Shen, Zhao-Yu Li +5
We explore the kinematics (both the radial velocity and the proper motion) of the vertical X-shaped feature in the Milky Way with an N-body bar/bulge model. From the solar perspect…
The X-Shaped Milky Way Bulge in OGLE-III Photometry and in N-Body Models
David M. Nataf, Andrzej Udalski, Jan Skowron +11
We model the split red clump of the Galactic bulge in OGLE-III photometry, and compare the results to predictions from two N-body models. Our analysis yields precise maps of the br…