Searching for classical Be stars in LAMOST DR1

Lin, Chien-Cheng; Hou, Jinliang; Chen, Li; Shao, Zhengyi; Zhong, Jianxin; Yu, Po-Chieh

doi:10.1088/1674-4527/15/8/015

Cited by 18 publications

(20 citation statements)

References 23 publications

(25 reference statements)

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“…Chojnowski et al (2015) presented 128 new Be stars with high-resolution near-infrared spectra (λ/Δλ=22,500) from the Apache Point Observatory Galactic Evolution Experiment (APOGEE; Majewski et al 2015). Also, Lin et al (2015) discovered 180 Be stars identified by the Large Sky Area Multi-Object fiber Spectroscopic Telescope (LAMOST; Cui et al 2012).…”

Section: Introductionmentioning

confidence: 99%

Searching for Be Stars in the Open Clusters with PTF/iPTF. I. Cluster Sample and Be Star Candidates

Lee

et al. 2018

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We conducted a search for Be star candidates in open clusters using Hα imaging photometry of the Palomar Transient Factory Survey to investigate some connections among Be star phenomena, cluster environments, and ages. Stellar members of clusters were identified by spatial distributions, near-infrared magnitudes and colors, and by proper motions. Among 104 open clusters, we identified 96 Be star candidates in 32 clusters; 11 of our candidates have been reported in previous studies. We found that the clusters with age 7.5 < log(t(year))  8.5 tend to have more Be star candidates; there is about a 40% occurrence rate within this age bin. The clusters in this age bin also tend to have a higher Be fraction N(Be)/N(Be+B-type). These results suggest that the environments of young and intermediate clusters are favorable to the formation of Be phenomena. Spatial distribution of Be star candidates with different ages implies that they do not form preferentially in the central regions. Furthermore, we showed that the mid-infrared (MIR) colors of the Be star candidates are similar to known Be stars, which could be caused by free-free emission or bound-free emission. Some Be star candidates might have no circumstellar dust according to their MIR colors. Finally, among 96 Be candidates, we discovered that one Be star candidate FSR 0904-1 exhibits long-term variability on the timescale of ∼2000 days with an amplitude of 0.2-0.3 mag, indicating a long timescale of disk evolution.

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Section: Introductionmentioning

confidence: 99%

Searching for Be Stars in the Open Clusters with PTF/iPTF. I. Cluster Sample and Be Star Candidates

Lee

et al. 2018

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“…In order to figure out the number of newly discovered objects, it is necessary to make sure how many known stars are recorded by the previous literatures in our sample. Objects with definite categories recorded by SIMBAD and other catalogues are discussed in this section (Kohoutek & Wehmeyer 1999;Zhang et al 2005;Witham et al 2008;Neiner et al 2011;Chojnowski et al 2015;Lin et al 2015).…”

Section: Objects Archived By Available Cataloguesmentioning

confidence: 99%

“…Besides, several catalogues related to CBe, HAeBe stars or Hα emission stars have been published in 8 W., Hou, A-li Luo et al Chojnowski et al 2015;Raddi et al 2015;Lin et al 2015). We also cross-match our sample with these catalogues to pick out the known CBe and HAeBe stars.…”

Section: Objects Archived By Available Cataloguesmentioning

confidence: 99%

A catalog of early-type emission-line stars and Hα line profiles from LAMOST DR2

Hou

Luo

et al. 2016

Res. Astron. Astrophys.

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We present a catalogue including 11,204 spectra for 10,436 early-type emissionline stars from LAMOST DR2, among which 9,752 early-type emission-line spectra are newly discovered. For these early-type emission-line stars, we discuss the morphological and physical properties from their low-resolution spectra. In this spectral sample, the Hα emission profiles display a wide variety of shapes. Based on the Hα line profiles, these spectra are categorized into five distinct classes: single-peak emission, single-peak emission in absorption, double-peak emission, double-peak emission in absorption, and P-Cygni profiles. To better understand what causes the Hα line profiles, we divide these objects into four types from the view of physical classification, which include classical Be stars, Herbig Ae/Be stars, close binaries and spectra contaminated by H II regions. The majority of Herbig Ae/Be stars and classical Be stars are identified and separated using the (H-K, K-W1) color-color diagram. We also discuss thirty one binary systems as listed in SIMBAD on-line catalogue and identify 3,600 spectra contaminated by H II regions after crossmatching with positions in the Dubout-Crillon catalogue. A statistical analysis of line profiles versus classifications is then conducted in order to understand the distribution of Hα profiles for each type in our sample. Finally, we also provide a table of 172 spectra with Fe II emission lines and roughly calculate stellar wind velocities for seven spectra with P-Cygni profiles.

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“…[18] and references therein), and therefore, when the peaks are defined in Eulerian density field, they are not described by the peak theory assuming Gaussian statistics of density fields. The statistics of peaks in the weak lensing fields are also useful in cosmology [19][20][21][22][23][24][25][26][27][28][29][30][31][32][33][34][35][36][37][38]. The weak lensing fields on interested scales are not Gaussian * Electronic address: tmats@post.kek.jp because of the nonlinear evolution of the density field which is the source of the weak lensing.…”

Section: Introductionmentioning

confidence: 99%

Statistics of peaks of weakly non-Gaussian random fields: Effects of bispectrum in two- and three-dimensions

Matsubara

2020

Phys. Rev. D

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Analytic expressions for the statistics of peaks of random fields with weak non-Gaussianity are provided. Specifically, the abundance and spatial correlation of peaks are represented by formulas which can be evaluated only by virtually one-dimensional integrals. We assume the non-Gaussianity is weak enough such that it is represented by linear terms of the bispectrum. The formulas are formally given in N-dimensional space, and explicitly given in the case of N = 1, 2, 3. Some examples of peak statistics in cosmological fields are calculated for the cosmic density field and weak lensing field, assuming the weak non-Gaussianity is induced by gravity. The formulas of this paper would find a fit in many applications to statistical analyses of cosmological fields.

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Searching for classical Be stars in LAMOST DR1

Cited by 18 publications

References 23 publications

Searching for Be Stars in the Open Clusters with PTF/iPTF. I. Cluster Sample and Be Star Candidates

Searching for Be Stars in the Open Clusters with PTF/iPTF. I. Cluster Sample and Be Star Candidates

A catalog of early-type emission-line stars and Hα line profiles from LAMOST DR2

Statistics of peaks of weakly non-Gaussian random fields: Effects of bispectrum in two- and three-dimensions

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