A5039010780- Stellar, planetary, and galactic studies
- Astrophysics and Star Formation Studies
- Galaxies: Formation, Evolution, Phenomena
- Astronomy and Astrophysical Research
- Astrophysics and Cosmic Phenomena
- Gamma-ray bursts and supernovae
- Astro and Planetary Science
- Astronomical Observations and Instrumentation
- Radio Astronomy Observations and Technology
- GNSS positioning and interference
- Astrophysical Phenomena and Observations
- Geophysics and Gravity Measurements
- Laser-Plasma Interactions and Diagnostics
- Molecular Spectroscopy and Structure
- Pulsars and Gravitational Waves Research
- Nuclear physics research studies
- Ionosphere and magnetosphere dynamics
- Particle physics theoretical and experimental studies
- Quantum Chromodynamics and Particle Interactions
- Laser-Matter Interactions and Applications
- Cosmology and Gravitation Theories
- Black Holes and Theoretical Physics
- Adaptive optics and wavefront sensing
- High-pressure geophysics and materials
- Atmospheric Ozone and Climate
Shanghai Astronomical Observatory
2016-2025
Sichuan University
2024
Aerospace Information Research Institute
2023
Shijiazhuang University
2023
Laser Fusion Research Center
2014-2021
Wuhan Donghu University
2020
Joint Institute for VLBI ERIC
2019
Shanghai Jiao Tong University
2017-2019
Purple Mountain Observatory
2016-2019
Leiden University
2019
We are using the Very Long Baseline Array and Japanese VLBI Exploration of Radio Astronomy project to measure trigonometric parallaxes proper motions masers found in high-mass star-forming regions across Milky Way. Early results from 18 sources locate several spiral arms. The Perseus arm has a pitch angle 16° ± 3°, which favors four rather than two arms for Galaxy. Combining positions, distances, motions, radial velocities yields complete three-dimensional kinematic information. find that on...
Over 100 trigonometric parallaxes and proper motions for masers associated with young, high-mass stars have been measured the Bar Spiral Structure Legacy Survey, a Very Long Baseline Array key science project, European VLBI Network, Japanese Exploration of Radio Astrometry project. These measurements provide strong evidence existence spiral arms in Milky Way, accurately locating many arm segments yielding pitch angles ranging from about 7° to 20°. The widths increase distance Galactic...
We compile and analyze ~200 trigonometric parallaxes proper motions of molecular masers associated with very young high-mass stars. These measurements strongly suggest that the Milky Way is a four-arm spiral. Fitting log-periodic spirals to locations masers, allows us significantly expand our view structure Way. present an updated model for its spiral incorporate it into previously published parallax-based distance-estimation program sources arms. Modeling three-dimensional space yields...
Trigonometric parallax measurements of nine water masers associated with the Local arm Milky Way were carried out as part BeSSeL Survey using VLBA. When combined 21 other from literature, data allow us to study distribution and 3-dimensional motions star forming regions in spiral over entire northern sky. Our results suggest that does not have large pitch angle characteristic a short spur. Instead its active formation, overall length (>5 kpc), shallow (~10 degrees) it is more like adjacent...
We report trigonometric parallaxes for three massive star-forming regions, corresponding to distances of 2.34+0.13−0.11 kpc G12.89+0.49 (also known as IRAS 18089−1732), 1.98+0.14−0.12 G15.03−0.68 (in the M17 region), and 8.0+4.0−2.0 G27.36−0.16. Both are located in Carina–Sagittarius spiral arm.
Abstract Astrometric Very Long Baseline Interferometry (VLBI) observations of maser sources in the Milky Way are used to map spiral structure our galaxy and determine fundamental parameters such as rotation velocity (Θ 0 ) curve distance Galactic center ( R ). Here, we present an update on first results, implementing a recent change knowledge about Solar motion. It seems unavoidable that IAU recommended values for Θ need substantial revision. In particular combination 8.5 kpc 220 km s –1 can...
We report four trigonometric parallaxes for high-mass star-forming regions within 4 kpc of the Galactic center. These measurements were made with VLBA as part BeSSeL Survey. By associating these sources kinematically large-scale features in CO and HI longitude-velocity diagrams, we begin to outline some major inner Milky Way: Connecting arm, near far 3 arms, Norma arm. The arm first quadrant lies closer center than is offset by long-bar's axis its leading edge, supporting presence an...
We report measurements of parallaxes and proper motions ten high-mass star-forming regions in the Sagittarius spiral arm Milky Way as part BeSSeL Survey with VLBA. Combining these results eight others from literature, we investigated structure kinematics between Galactocentric azimuth around -2 65 deg. found that pitch angle is 7.3 +- 1.5 deg; arm's half-width, defined rms deviation fitted spiral, 0.2 kpc; nearest portion 1.4 kpc Sun. Unlike for adjacent arms, no evidence significant...
<i>Aims. <i/>We study the chemical evolution of disks Milky Way (MW) and Andromeda (M 31), to identify common properties differences between two major galaxies Local Group.<i>Methods. use a large set observational data for M 31, including observations star formation rate (SFR) gas profiles, as well stellar metallicity distributions along its disk. When expressed in terms corresponding disk scale lengths, we show that observed radial profiles MW 31 exhibit interesting similarities, suggesting...
We report trigonometric parallax measurements of 22 GHz H$_2$O masers in two massive star-forming regions from VLBA observations as part the BeSSeL Survey. The distances $11.11^{+0.79}_{-0.69}$ kpc to W49N (G043.16+0.01) and $10.75^{+0.61}_{-0.55}$ G048.60+0.02 locate them a distant section Perseus arm near solar circle first Galactic quadrant. This allows us accurately inner portion for time. Combining present results with sources measured outer second third quadrants yields global pitch...
We report trigonometric parallax measurements of masers in the massive star-forming complex W43 from Very Long Baseline Array observations as part Bar and Spiral Structure Legacy Survey. Based on three 12 GHz methanol maser sources (G029.86−00.04, G029.95−00.01, G031.28+00.06) one 22 water source (G031.58+00.07) toward W43, we derived a distance kpc to W43. By associating with CO molecular clouds, clouds kinematically longitude–velocity spiral features, assign Scutum arm, close near end...
We report measurements of trigonometric parallaxes for six high-mass star-forming regions in the Scutum spiral arm Milky Way as part BeSSeL Survey. Combining our with 10 previous from Survey yields a total sample 16 sources Galactic longitude range 5° to 32°. Assuming logarithmic model, we estimate pitch angle 198 ± 31 arm, which is larger than angles reported other arms. The high may be due arm's proximity bar. show an average peculiar motion 4 km s−1 slower rotation and 8 toward center....
The nature of the spiral structure Milky Way has long been debated. Only in last decade have astronomers able to accurately measure distances a substantial number high-mass star-forming regions, classic tracers galaxies. We report distance measurements at radio wavelengths using Very Long Baseline Array for eight regions massive star formation near Local arm Way. Combined with previous measurements, these observations reveal that Arm is larger than previously thought, and both its pitch...
Aims.Our aims are to estimate the validity of empirical methods, such as R23, , log([N ii]/Hα) (N2), log[ ([O iii]/Hβ)/ ([N ii]/Hα)] (O3N2), and log([S (S2), re-derive (or add) calibrations N2, O3N2, S2 indices for oxygen abundances on basis a large sample galaxies with Te-based abundances.
We report trigonometric parallaxes for the high-mass star-forming regions G35.20−0.74 and G35.20−1.74, corresponding to distances of 2.19+0.24−0.20 kpc 3.27+0.56−0.42 kpc, respectively. The both sources are close their near kinematic place them in Carina–Sagittarius spiral arm. Combining proper motions with observed radial velocities gives locations full space regions. Assuming a standard model Galaxy, G35.20−1.74 have peculiar ≈13 km s−1 ≈16 counter Galactic rotation ≈9 toward North Pole.
We report astrometric results of phase-referencing very long baseline interferometry observations 43 GHz SiO maser emission toward the red hypergiant VY Canis Majoris (VY CMa) using Very Long Baseline Array (VLBA). measured a trigonometric parallax 0.83 ± 0.08 mas, corresponding to distance 1.20+0.13−0.10 kpc. Compared previous studies, spatial distribution masers has changed dramatically, while its total extent remains similar. The internal motions spots are up 1.4 mas yr−1, 8 km s−1, and...
We compare the parallaxes of stars from VLBI astrometry in literature to those Gaia DR2 catalog. Our full sample contains young stellar objects, evolved AGB stars, pulsars and other radio stars. Excluding which show significant discrepancies between parallaxes, binary systems, we obtain an average, systematic, parallax offset $-75 \pm 29~\mu$as for DR2, consistent with their estimate a zero-point $-100$ 0 $\mu$as.
Abstract Only a handful of massive starless core candidates have been discovered so far, but none them fully confirmed. Within the MM1 clump in filamentary infrared dark cloud G34.43+0.24 that was covered by Atacama Large Millimeter/submillimeter Array (ALMA) ATOMS survey at Band 3 (∼2″, 6000 au) and ALMA-QUARKS 6 (∼0.″3, 900 au), two prestellar MM1-C E1 with masses 71 20 M ⊙ radii 2100–4400 au were discovered. The cores show no obvious sign star formation activities. In particular, is very...
In this Letter we suggest that the obvious discrepancy between theoretical prediction on non-DD¯ decays of ψ(3770) and data is to be alleviated by taking final state interaction (FSI) into account. By assuming overwhelmingly dissociates DD¯, then induces a secondary process, calculate branching ratios ψ(3770)→DD¯→J/ψη, ρπ, ωη, K∗K. Our results show ratio ψ(3770)→non-DD¯ can reach up Bnon-DD¯FSI=(0.2–1.1)% while typical parameters I=0.4GeV−2 α=0.8–1.3 are adopted. This indicates FSI obviously...
In increasingly popular participatory sensing systems, new challenges are arising to select the most appropriate participants when considering their hand-held smart device's different energy conditions, uncontrollable mobility pattern, and associated capabilities best satisfy quality-of-information (QoI) requirements of tasks. This paper proposes a QoI-aware energy-efficient participant selection strategy, where four key design elements proposed. First is QoI satisfaction metric task that...
Context . The Gaia mission has released the second data set ( DR2), which contains parallaxes and proper motions for a large number of massive, young stars. Aims We investigate spiral structure in solar neighborhood revealed by DR2 compare it with that depicted VLBI maser parallaxes. Methods examined three samples different constraints on parallax uncertainty distance errors stellar spectral types: (1) all OB stars less than 10%; (2) only O-type 0.1 mas imposed 0.2 kpc; (3) 0.05 0.3 kpc....
As part of the BeSSeL Survey, we report trigonometric parallaxes and proper motions molecular maser sources associated with 13 distant high mass star forming regions in Sagittarius spiral arm Milky Way. In particular, obtain improved parallax distance estimates for three well studied regions: 1.9 +0.1/-0.1 kpc M17, 5.3 +1.3/-0.9 W51, 7.9 +0.9/-0.7 GAL 045.5+00.0. Peculiar all but one source are less than 20 km/s. We fit a log-periodic to locations estimate an average pitch angle 7.2+-1.9...