Search Publications
The structure and 3D kinematics of vela OB2
Wright, Nicholas J.; Cantat-Gaudin, Tristan; Jeffries, R. D. +2 more
The kinematics of stars in OB associations can provide insights into their formation, dynamical evolution, and eventual fate. The low-mass stellar content of OB associations are sufficiently numerous as to provide a detailed sampling of their kinematic properties, however spectroscopy is required to confirm the youth of individual stars and to get…
Bending waves excited by irregular gas inflow along warps
Debattista, Victor P.; Beraldo e Silva, Leandro; Khachaturyants, Tigran +1 more
Gaia has revealed clear evidence of bending waves in the vertical kinematics of stars in the solar neighbourhood. We study bending waves in two simulations, one warped, with the warp due to misaligned gas inflow, and the other unwarped. We find slow, retrograde bending waves in both models, with the ones in the warped model having larger amplitude…
Nebular-phase spectra of Type Ia supernovae from the Las Cumbres Observatory Global Supernova Project
Wheeler, J. C.; Galbany, L.; Howell, D. A. +17 more
The observed diversity in Type Ia supernovae (SNe Ia) - the thermonuclear explosions of carbon-oxygen white dwarf stars used as cosmological standard candles - is currently met with a variety of explosion models and progenitor scenarios. To help improve our understanding of whether and how often different models contribute to the occurrence of SNe…
Characterization of hot populations of Melotte 66 open cluster using Swift/UVOT
Subramaniam, Annapurni; Panthi, Anju; Vaidya, Kaushar +3 more
Ultraviolet (UV) wavelength observations have made a significant contribution to our understanding of hot stellar populations of star clusters. Multiwavelength spectral energy distributions (SEDs) of stars, including ultraviolet observations, have proven to be an excellent tool for discovering unresolved hot companions in exotic stars such as blue…
Phase spirals in cosmological simulations of Milky Way-sized galaxies
Antoja, T.; Ramos, P.; García-Conde, B. +2 more
We study the vertical perturbations in the galactic disc of the Milky Way-size high-resolution hydrodynamical cosmological simulation named GARROTXA. We detect phase spirals in the vertical projection Z - VZ of disc's stellar particles for the first time in this type of simulations. Qualitatively similar structures were detected in the …
Ensemble-based unsupervised machine learning method for membership determination of open clusters using Mahalanobis distance
Deb, Sukanta; Baruah, Amiya; Kumar, Subhash
We present an improved method for the determination of membership of an open cluster using ensemble-based unsupervised machine learning techniques. The working principle of this method relies on two stages: (i) choosing a suitable range of three astrometric parameters (π, µαcos δ, µδ) using k-nearest neighbour (kN…
TYC 2990-127-1: An Algol-type SB2 binary system of subgiant and red giant with a probable ongoing mass-transfer
Han, Zhanwen; Kovalev, Mikhail; Chen, Xuefei +3 more
We present a study of the spectroscopic binary TYC 2990-127-1 from the LAMOST survey. We use full-spectrum fitting to derive radial velocities and spectral parameters. The high mass ratio indicates that the system underwent mass transfer in the past. We compute the orbital solution and find that it is a very close sub-giant/red giant pair on circu…
Measuring weak lensing masses on individual clusters
Melin, Jean-Baptiste; Bartlett, James G.; Murray, Calum +1 more
We present weak lensing mass estimates for a sample of 458 galaxy clusters from the redMaPPer Sloan Digital Sky Survey DR8 catalogue using Hyper Suprime-Cam weak lensing data. We develop a method to quickly estimate cluster masses from weak lensing shear and use this method to estimate weak lensing masses for each of the galaxy clusters in our sam…
Identification, mass, and age of primary red clump stars from spectral features derived with the LAMOST DR7
Luo, A. -Li; Chen, Yu-Qin; He, Xu-Jiang
Although red clump (RC) stars are easy to identify due to their stability of luminosity and colour, about 20-50 per cent are actually red giant branch (RGB) stars in the same location on the HR diagram. In this paper, a sample of 210 504 spectra for 184 318 primary RC (PRC) stars from the LAMOST DR7 is identified, which has a purity of higher than…
MUSE sneaks a peek at extreme ram-pressure stripping events - V. Towards a complete view of the galaxy cluster A1367
Fumagalli, Michele; Yoshida, Michitoshi; Fossati, Matteo +6 more
We present an analysis of the kinematics and ionization conditions in a sample composed of seven star-forming galaxies undergoing ram-pressure stripping in the A1367 cluster, and the galaxy ESO137-001 in the Norma cluster. MUSE observations of two new galaxies in this sample, CGCG097-073 and CGCG097-079, are also presented. This sample is characte…