Search Publications
Magnetic activity and age estimation of red giants using neural networks
Lu, Hong-peng; Zhang, Li-yun; Karoff, Christoffer
In this work, we analysed the magnetic activity of 5349 Large Sky Area Multi-Object Fiber Spectroscopic Telescope (LAMOST) low-dispersion spectra of 3539 red giants by calculating equivalent width (EW) of magnetic activity lines (H α, H β, H γ, H δ, $\rm{Ca~{ii} H\&K}$, $\rm{Ca~{ii} IRT}$). Combining LAMOST spectral parameters, asteroseismic p…
Effects of flares on solar high-degree helioseismic acoustic mode amplitudes
Rabello Soares, M. Cristina; Baudin, Frédéric; Teixeira, Vanessa G.
Several attempts have been made to observe whether solar flares excite acoustic modes since Charles Wolff suggested this possibility almost 50 yr ago. We look for the impact of flares on the amplitude of solar acoustic modes and other effects that are also affecting the mode amplitude. Solar acoustic mode amplitudes are known to be sensitive to ma…
Observing the influence of the youngest super star clusters in NGC 1569: Keck Brackett α spectroscopy
Turner, Jean L.; Beck, Sara C.; Consiglio, S. Michelle +1 more
We report Keck-NIRSPEC observations of the Brackett α 4.05 µm recombination line across the two candidate embedded super star clusters (SSCs) in NGC 1569. These SSCs power a bright H II region and have been previously detected as radio and mid-infrared sources. Supplemented with high-resolution VLA mapping of the radio continuum along with I…
gzK-colour-selected star-forming galaxies in the AKARI NEP-Deep Field
Goto, Tomotsugu; Pearson, Chris; Jeong, Woong-Seob +7 more
We study the clustering property and physical parameters of gzK-colour-selected star-forming galaxies (sgzKs) based on the Canada-France-Hawaii Telescope surveys over 0.55 deg2 in the AKARI North Ecliptic Pole-Deep Field. Two-point correlation functions for two magnitude-limited cases, Ks < 21.1 (N = 234) and Ks…
Relationship between magnetic field properties and statistical flow using numerical simulation and magnetic feature tracking on solar photosphere
Oba, T.; Iida, Y.; Hotta, H. +1 more
We perform radiative magnetohydrodynamic calculations for the solar-quiet region to investigate the dependence of statistical flow on magnetic properties and the three-dimensional structure of magnetic patches in the presence of large-scale flow that mimics differential rotation. It has been confirmed that strong magnetic field patches move faster…
M dwarf spectral indices at moderate resolution: accurate Teff and [Fe/H] for 178 southern stars
Lorenzo-Oliveira, Diego; Costa-Almeida, Ellen; Porto de Mello, Gustavo F. +2 more
We present a spectroscopic and photometric calibration to derive effective temperatures Teff and metallicities [Fe/H] for M dwarfs, based on a principal component analysis (PCA) of 147 spectral indices measured off moderate resolution (R~11 000), high S/N (>100) spectra in the λλ 8390-8834 region, plus the J-H colour. Internal uncert…
New insight into the formation mechanism of the energetic particle reservoirs in the heliosphere
He, H. -Q.
The concept of energetic particle reservoirs, essentially based on the assumption of the presence of outer reflecting boundaries/magnetic mirrors or diffusion barriers (deterministic) rather than on the effect of particle diffusive propagation (stochastic) in magnetic turbulence, has been used for decades to describe the space-extended decay phase…
The Herschel SPIRE Fourier Transform Spectrometer Spectral Feature Finder - V. Rotational measurements of NGC 891
Valtchanov, I.; Spencer, L. D.; Hładczuk, N. +2 more
The ESA Herschel Spectral and Photometric Imaging Receiver (SPIRE) Fourier Transform Spectrometer (FTS) Spectral Feature Finder (FF) project is an automated spectral feature fitting routine developed within the SPIRE instrument team to extract all prominent spectral features from all publicly available SPIRE FTS observations. In this work, we demo…
A geometrical description for interplanetary propagation of Earth-directed CMEs based on radiative proxies
Salas-Matamoros, C.; Sanchez-Guevara, J.
We present a 3D geometrical model to describe the propagation and expansion of coronal mass ejections (CMEs) in the interplanetary space based on radiative proxies to be implemented in previous procedures that use SXR and microwave emissions to estimate the Earth-directed CME propagation speed. We carefully selected a sample of 45 well-defined CME…