A5052013057- Stellar, planetary, and galactic studies
- Astronomy and Astrophysical Research
- Astrophysics and Star Formation Studies
- Galaxies: Formation, Evolution, Phenomena
- Gamma-ray bursts and supernovae
- Astrophysical Phenomena and Observations
- Astronomical Observations and Instrumentation
- Astro and Planetary Science
- Solar and Space Plasma Dynamics
- Spectroscopy and Laser Applications
- Anomaly Detection Techniques and Applications
- Time Series Analysis and Forecasting
- CCD and CMOS Imaging Sensors
- Molecular spectroscopy and chirality
- Adaptive optics and wavefront sensing
- Spectroscopy and Chemometric Analyses
- Advanced Vision and Imaging
- Blind Source Separation Techniques
National Astronomical Observatories
2012-2022
Chinese Academy of Sciences
2012-2021
University of Chinese Academy of Sciences
2014-2016
Academia Sinica
2012
The Large sky Area Multi-Object Spectroscopic Telescope (LAMOST) General Survey is a spectroscopic survey that will eventually cover approximately half of the celestial sphere and collect 10 million spectra stars, galaxies QSOs. Objects both in pilot first year general are included LAMOST First Data Release (DR1). started October 2011 ended June 2012, data have been released to public as Pilot August 2012. September completed its operation 2013. DR1 includes total 1202 plates containing...
This paper describes the data release of LAMOST pilot survey, which includes reduction, calibration, spectral analysis, products and access. The accuracy released information about FITS headers spectra are also introduced. set 319 000 a catalog these objects.
We present Data Releases 4 and 5 of the quasar catalog from survey by Large Sky Area Multi-object Fiber Spectroscopic Telescope (LAMOST), which includes quasars observed between 2015 September 2017 June. There are a total 19,253 identified visual inspections spectra. Among them, 11,458 were independently discovered LAMOST, in 3296 reported SDSS DR12 DR14 after our began, while remaining 8162 new discoveries LAMOST. provide emission line measurements for Hα, Hβ, Mg ii, and/or C iv 18,100...
We present a spectroscopic catalog of 58,360 M dwarfs from the Large Sky Area Multi-Object Fiber Spectroscopic Telescope pilot survey. For each spectrum in catalog, spectral subtype, radial velocity, Hα equivalent width, number prominent molecular band indices, and metal-sensitive parameter ζ are provided. use Sloan Digital Survey Data Release 7 dwarf to verify precision our methods classifying types measuring velocities. The magnetic activity properties also traced by emission lines....
This is the second installment for Large Sky Area Multi-Object Fibre Spectroscopic Telescope (LAMOST) Quasar Survey, which includes quasars observed from September 2013 to June 2015. There are 9024 confirmed in DR2 and 10911 DR3. After cross-match with SDSS quasar catalogs NED, 12126 discovered independently. Among them 2225 were released by DR12 QSO catalogue 2014 after we finalised survey candidates. 1801 sources identified DR14 as QSOs. The remaining 8100 considered newly founded, among...
Abstract The radial velocity (RV) is a basic physical quantity that can be determined through the Doppler shift of spectrum star. precision RV measurement depends on resolution we used and accuracy wavelength calibration. In this work, velocities Large Sky Area Multi-Object Fibre Spectroscopic Telescope-II (LAMOST-II) medium-resolution ( R ∼ 7500) spectra are measured for 1,594,956 (each has two wavebands) matching with templates. A set standard stars to recalibrate zero point measurement,...
We study the classification and composite spectra of galaxy in fourth data release (DR4) Large Sky Area Multi-Object Fiber Spectroscopic Telescope (LAMOST). select 40,182 galaxies from LAMOST DR4, which have photometric in- formation but no spectroscopic observations Sloan Digital Survey(SDSS). These newly observed are re-calibrated classified into six classes, i.e. pas- sive, H{\alpha}-weak, star-forming, composite, LINER Seyfert using line intensity (H\b{eta}, [OIII]{\lambda}5007,...
A sample of Cataclysmic Variables (CVs) is presented including spectroscopically identified 380 spectra 245 objects, which 58 CV candidates are new discoveries. The BaggingTopPush and the Random Forest algorithms applied to Fifth Data Release (DR5) LAMOST retrieve CVs with strong emission lines broad absorption respectively. Based on spectroscopic classification, 134 dwarf novae, 41 nova-like variables 19 magnetic from sample. In addition, 89 high--inclination systems 33 showing companion...
Abstract We derive a catalog of early-type emission-line stars including 30,023 spectra 25,867 from LAMOST Data Release 7, in which 4189 have Simbad records. The are classified into three morphological types (10 subtypes) based on H α profiles. Some contaminated by nebula emission lines such as ii regions flagged the catalog. also provide specific 20 with stellar winds or accretion flows calculating terminal and peak velocities P-Cygni inverse More important, two color–color diagrams, (H-K s...
The LAMOST spectral analysis pipeline, called the 1D aims to classify and measure spectra observed in survey. Through this stellar are classified into different subclasses by matching with template spectra. Consequently, performance of classification greatly depends on quality In paper, we construct a new library, which is supposed improve precision credibility present classification. About one million selected from Data Release One templates, they gathered 233 groups two criteria: (1)...
ABSTRACT The task of flux calibration for Large sky Area Multi-Object Spectroscopic Telescope (LAMOST) spectra is difficult due to many factors, such as the lack standard stars, flat-fielding large field view, and variation reddening between different especially at low Galactic latitudes. Poor selection, bad spectral quality, or extinction uncertainty stars not only might induce errors calculated response curve (SRC) but also lead failures in producing final 1D spectra. In this paper, we...
We present a sample of metallic-line star (Am) candidates from the Large Sky Area Multi-Object Fibre Spectroscopic Telescope (LAMOST) Data Release One (DR1). According to characteristic underabundance calcium and overabundance iron element Am stars, we propose an empirical separation curve derived line indices Ca ii K lines choose for low-resolution spectra. Ultimately, 3537 are selected more than 30 000 which classified as A-type or early F-type stars by both LAMOST pipeline visual...
Abstract The Large Sky Area Multi-Object Fibre Spectroscopic Telescope data release 5 (DR5) released more than 200,000 low-resolution spectra of early-type stars with a signal-to-noise ratio > 50. search for metallic-line (Am) in such large database and study their statistical properties are presented this paper. Six machine-learning algorithms were experimented using known Am spectra, both the empirical criteria method MKCLASS package also investigated. Comparing performance, random...
We outline a full-scale search for galaxies exhibiting double-peaked profiles of promi- nent narrow emission lines, motivated by the prospect finding objects related to merging galaxies, and even dual active galactic nuclei candidates as by-product, from Large Sky Area Multi-object Fiber Spectroscopic Telescope (LAMOST) Data Re- lease 4. assemble large sample 325 with or strong asymmetric 33 therein appearing optically resolved dual-cored structures, close companions signs recent interaction...
Abstract In this work, we present a catalog of 2651 carbon stars from the fourth Data Release (DR4) Large Sky Area Multi-Object Fiber Spectroscopy Telescope (LAMOST). Using an efficient machine-learning algorithm, find these more than 7 million spectra. As by-product, 17 carbon-enhanced metal-poor turnoff star candidates are also reported in paper, and they preliminarily identified by their atmospheric parameters. Except for 176 that could not be given spectral types, classify other 2475...
Abstract We examine a sample of 340 cataclysmic variables (CVs) from the latest data release Large Sky Area Multi-Object Fiber Spectroscopic Telescope (LAMOST) survey, along with 18 objects that are newly classified as CVs. In this paper, we focus on investigating photometric behaviors these CVs using time-domain surveys. The orbital periods three new and five previously known determined long-term light curves displaying eclipses or ellipsoidal variations, and/or time-resolved spectra...
The fundamental stellar atmospheric parameters T_eff and log g 13 chemical abundances are derived for medium-resolution spectroscopy from LAMOST Medium-Resolution Survey (MRS) data sets with a deep-learning method. neural networks we designed, named as SPCANet, precisely map MRS spectra to abundances. labels by SPCANet precisions of 119 K 0.17 dex g. abundance precision 11 elements including [C/H], [N/H], [O/H], [Mg/H], [Al/H], [Si/H], [S/H], [Ca/H], [Ti/H], [Cr/H], [Fe/H], [Ni/H] 0.06~0.12...
One of the most important aims astronomical data mining is to systematically search for specific rare objects in a massive spectral set, given small fraction identified samples with same type. Most existing methods are mainly based on binary classification, which usually suffers from incompleteness when there too few known samples. Rank-based could provide good solutions such cases. After investigating several algorithms, method combining bipartite ranking model bootstrap aggregating...
We present a catalog including 11 204 spectra of 10 436 early-type emission-line stars from LAMOST DR2, among which 9752 are newly discovered. For these stars, we discuss the morphological and physical properties their low-resolution spectra. In this spectral sample, Hα emission profiles display wide variety shapes. Based on line profiles, categorized into five distinct classes: single-peak emission, in absorption, double-peak P-Cygni profiles. To better understand what causes divide objects...
Applying the revised M subdwarf classification criteria discussed in Paper I to LAMOST DR7, combining sample from Savcheva et al, a new was constructed for further study. The atmospheric parameters each object were derived fitting with PHOENIX grid, Gaia DR2, relationship between gravity and metallicity explored according locus both color-absolute magnitude diagram reduced proper motion diagram. Objects that have largest lowest are located away main-sequence cloud may be considered as...
We spectroscopically identify 101 Galactic HII regions using spectra from the Large Sky Area Multi- Object Fiber Spectroscopic Telescope (LAMOST) survey, cross-matched with an region catalog derived all-sky Wide-Field Infrared Survey Explorer(WISE) data. Among all in our sample, 47 sources are newly confirmed. Spatially, most of identified located anti-center area Galaxy. For each regions, we accurately extract and measure nebular emission lines spectra, estimate oxygen abundances...
We identify 108 M subdwarfs (sdMs) out of more than two hundred thousand type spectra from the second data release (DR2) LAMOST regular survey. This sample, among which 58 members are identified for first time, includes 33 extreme (esdMs) and 11 ultra (usdMs). The selection is based on usual ratio absorption depth CaH2, CaH3 TiO5 band systems. also emphasize use CaH1 band. provide estimates spectral subtype (SPT), Lépine metallicity index ζ, effective temperature [Fe/H]. Both ζ—[Fe/H]...
A sample of 70 E+A galaxies is selected from 37 206 in the second data release Large Sky Area Multi-Object Fiber Spectroscopic Telescope (LAMOST). This according to criteria for defined by Goto, and each these objects further visually identified. In this sample, most are low redshift with z < 0.25, located an area sky high Galactic latitude magnitude 14 18 mag g, r i bands. stellar population analysis whole indicates that characterized both young old populations (SPs), metalrich SPs have...
In this study, the fundamental stellar atmospheric parameters (Teff, log g, [Fe/H], and [α/Fe]) were derived for low-resolution spectroscopy from LAMOST DR5 with generative spectrum networks (GSN). This follows same scheme as a normal artificial neural network input spectra output. The GSN model was effective in producing synthetic after training on PHOENIX theoretical spectra. combination Bayes framework, application analysis of observed exhibited improved efficiency distributed-computing...
We present an empirical stellar spectra library created using from the Large Sky Area Multi-Object Fiber Spectroscopic Telescope (LAMOST) DR5. This represents a uniform data set ranging 3750 through 8500K in effective temperature (T_eff), -2.5 +1.0 dex metallicity ([Fe/H]), and 0 to 5.0 gravity (log g). The have resolution R~1800, with well-calibrated fluxes rest-framed wavelengths. Using large number of red stars observed by LAMOST, we generated denser K type templates fill missing current...