200 citations · 394 across the 21 of their papers we have counts for
21 papers
Strange Quasar Candidates with Abnormal Astrometric Characteristics from Gaia EDR3 and SDSS (SQUAB-II): Optical Identifications
Xiang Ji, Zhen-Ya Zheng, Qiqi Wu +7
There are some strange quasars with multiple Gaia detections or observed with abnormal astrometric characteristics, such as with large proper motions or significant astrometric noi…
Astrometric Calibration of the BeijingArizona Sky Survey
Xiyan Peng, Zhaoxiang Qi, Tianmeng Zhang +13
We present the astrometric calibration of the Beijing-Arizona Sky Survey (BASS). The BASS astrometry was tied to the International Celestial Reference Frame via the \emph{Gaia} Dat…
Simulation of CSSTs astrometric capability
Zhensen Fu, Zhaoxiang Qi, Shilong Liao +5
The China Space Station Telescope (CSST) will enter a low Earth orbit around 2024 and operate for 10 years, with seven of those years devoted to surveying the area of the median-to…
Relative astrometry in an annular field
Mario Gai, Alberto Vecchiato, Alberto Riva +4
Background. Relative astrometry at or below the micro-arcsec level with a 1m class space telescope has been repeatedly proposed as a tool for exo-planet detection and characterizat…
Astrometric precision tests on TESS data
Mario Gai, Alberto Vecchiato, Alberto Riva +5
Background. Astrometry at or below the micro-arcsec level with an imaging telescope assumes that the uncertainty on the location of an unresolved source can be an arbitrarily small…
ET White Paper: To Find the First Earth 2.0
Jian Ge, Hui Zhang, Weicheng Zang +163
We propose to develop a wide-field and ultra-high-precision photometric survey mission, temporarily named "Earth 2.0 (ET)". This mission is designed to measure, for the first time,…
CHES: a space-borne astrometric mission for the detection of habitable planets of the nearby solar-type stars
Jianghui Ji, Haitao Li, Junbo Zhang +19
The Closeby Habitable Exoplanet Survey (CHES) mission is proposed to discover habitable-zone Earth-like planets of the nearby solar-type stars ( away from our…
SQUAB I: The first release of Strange QUasar candidates with ABnormal astrometric characteristics from Gaia EDR3 and SDSS
Qi-Qi Wu, Shi-Long Liao, Xiang Ji +4
Given their extremely large distances and small apparent sizes, quasars are generally considered as objects with near-zero parallax and proper motion. However, some special quasars…
A catalog of quasar candidates identified by astrometric and mid-infrared methods in Gaia EDR3
Qiqi Wu, Shilong Liao, Zhaoxiang Qi +3
Quasars are very important in materializing the reference frame. The excess emission of AGNs (active galactic nuclei) in the mid infrared band can be used to identify quasar candid…
LAMOST Medium-Resolution Spectral Survey of Galactic Nebulae (LAMOST-MRS-N): Subtraction of Geocoronal Halpha Emission
Wei Zhang, Hong Wu, Chaojian Wu +10
We introduce a method of subtracting geocoronal Halpha emissions from the spectra of LAMOST medium-resolution spectral survey of Galactic nebulae (LAMOST-MRS-N). The flux ratios of…
Progress on the Astrometric Gravitation Probe design
Mario Gai, Alberto Vecchiato, Alberto Riva +13
The Astrometric Gravitation Probe mission is a modern version of the 1919 Dyson-Eddington-Davidson experiment, based on a space-borne telescope with a permanent built-in eclipse, p…
The ASTRA project: a doorway to future astrometry
Mario Gai, Zhaoxiang Qi, Mario G. Lattanzi +15
Astrometric Science and Technology Roadmap for Astrophysics (ASTRA) is a bilateral cooperation between China and Italy with the goal of consolidating astrometric measurement concep…
RAFTER: Ring Astrometric Field Telescope for Exo-planets and Relativity
Alberto Riva, Mario Gai, Alberto Vecchiato +5
High precision astrometry aims at source position determination to a very small fraction of the diffraction image size, in high SNR regime. One of the key limitations to such goal…
A wide star-black-hole binary system from radial-velocity measurements
Jifeng Liu, Haotong Zhang, Andrew W. Howard +52
All stellar mass black holes have hitherto been identified by X-rays emitted by gas that is accreting onto the black hole from a companion star. These systems are all binaries with…
Identifying quasars with astrometric and mid-infrared methods from APOP and ALLWISE
Sufen Guo, Zhaoxiang Qi, Shilong Liao +5
Context. Quasars are spatially stationary, and they are essential objects in astrometry when defining reference frames. However, the census of quasars is far from complete. Mid-inf…
A compilation of known QSOs for the Gaia mission
Shi-long Liao, Zhao-xiang Qi, Su-fen Guo +1
Quasars are essential for astrometric in the sense that they are spatial stationary because of their large distance from the Sun. The European Space Agency (ESA) space astrometric…
The properties of the quasars astrometric solution in Gaia DR2
Shilong Liao, Beatric Bucciarelli, Zhaoxiang Qi +3
Gaia data release 2 (DR2) provides the best non-rotating optical frame aligned with the radio frame (ICRF) thanks to the inclusion of about half-million quasars in the 5-parameter…
Low-resolution near-infrared spectroscopic signatures of unresolved ultracool companions to M dwarfs
N. J. Cook, D. J. Pinfield, F. Marocco +14
We develop a method to identify the spectroscopic signature of unresolved L-dwarf ultracool companions, which compares the spectra of candidates and their associated control stars…
An Investigation of the Absolute Proper Motions of the SCUSS Catalog
Xiyan Peng, Zhaoxiang Qi, Zhenyu Wu +21
Absolute proper motions for 7.7 million objects were derived based on data from the South Galactic Cap u-band Sky Survey (SCUSS) and astrometric data derived from uncompress…
A geometric delay model for Space VLBI
Shi-Long Liao, Zheng-Hong Tang, Zhao-Xiang Qi
A relativistic delay model for space very long baseline interferometry (hereafter SVLBI) observation of sources at infinite distance is derived. In SVLBI, where one station is on a…
The LAMOST Survey of Background Quasars in the Vicinity of the Andromeda and Triangulum Galaxies -- II. Results from the Commissioning Observations and the Pilot Surveys
Zhi-Ying Huo, Xiao-Wei Liu, Mao-Sheng Xiang +68
We present new quasars discovered in the vicinity of the Andromeda and Triangulum galaxies with the LAMOST during the 2010 and 2011 observational seasons. Quasar candidates are sel…