Search Publications
An excitation mechanism for discrete chorus elements in the magnetosphere
Bespalov, Peter; Savina, Olga
A beam pulsed amplifier mechanism responsible for effective amplification of short very low frequency (VLF) electromagnetic pulses is proposed. Effective amplification near the magnetic equator outside the plasmasphere is considered. A conditional growth rate of short electromagnetic pulses is calculated. Obtained results can explain some importan…
They Might Be Giants: An Efficient Color-based Selection of Red Giant Stars
Conroy, Charlie; Dotter, Aaron; Johnson, Benjamin D. +4 more
We present a color-based method for identifying red giants based on the Pan-STARRS grz and WISE W1 and W2 photometry. We utilize a subsample of bright stars with precise parallaxes from Gaia’s second data release (DR2) to verify that the color-based selection reliably separates dwarfs from giants. The selection is conservative in the sense that co…
Constraining the nature of DG Tau A's thermal and non-thermal radio emission
Purser, S. J. D.; Ray, T. P.; Taylor, A. M. +3 more
DG Tau A, a class-II young stellar object (YSO), displays both thermal and non-thermal radio emission associated with its bipolar jet. To investigate the nature of this emission, we present sensitive (σ ∼ 2 {µ Jy} beam^{-1}), Karl G. Jansky Very Large Array (VLA) 6 and 10 GHz observations. Over 3.81 yr, no proper motion is observed towards t…
Cluster Observations of a Dispersive Flapping Event of Magnetotail Current Sheet
Petrukovich, A. A.; Wei, Y.; Lui, A. T. Y. +5 more
A kink-like flapping event of Earth magnetotail current sheet, which consists of two frequency bands successively, is studied by the multipoint observations of Cluster. The multipoint analysis of Cluster observations demonstrates that the higher frequency band (period is about 10 min) has faster propagation velocity (about 30 km/s), shorter wavele…
Particle simulation of electromagnetic emissions from electrostatic instability driven by an electron ring beam on the density gradient
Omura, Yoshiharu; Santolík, Ondřej; Horký, Miroslav
This paper presents the wave mode conversion between electrostatic and electromagnetic waves on the plasma density gradient. We use 2-D electromagnetic code KEMPO2 implemented with the generation of density gradient to simulate such a conversion process. In the dense region, we use ring beam instability to generate electron Bernstein waves and we …
IGR J19294+1816: a new Be-X-ray binary revealed through infrared spectroscopy
Solano, E.; Torrejón, J. M.; Rodes-Roca, J. J. +2 more
The aim of this work is to characterize the counterpart to the INTErnational Gamma-Ray Astrophysics Laboratory high-mass X-ray binary candidate IGR J19294+1816 so as to establish its true nature. We obtained H-band spectra of the selected counterpart acquired with the Near Infrared Camera and Spectrograph instrument mounted on the Telescopio Nazio…
Angular Sizes and Effective Temperatures of O-type Stars from Optical Interferometry with the CHARA Array
Gies, Douglas R.; Schaefer, Gail H.; Hillier, D. John +3 more
We present interferometric observations of six O-type stars that were made with the Precision Astronomical Visible Observations beam combiner at the Center for High Angular Resolution Astronomy (CHARA) Array. The observations include multiple brackets for three targets, λ Ori A, ζ Oph, and 10 Lac, but there are only preliminary, single observation…
Jeans that fit: weighing the mass of the Milky Way analogues in the ΛCDM universe
Sharma, Sanjib; Driver, Simon P.; Robotham, Aaron S. G. +2 more
The spherical Jeans equation is a widely used tool for dynamical study of gravitating systems in astronomy. Here, we test its efficacy in robustly weighing the mass of Milky Way analogues, given they need not be in equilibrium or even spherical. Utilizing Milky Way stellar haloes simulated in accordance with Λ cold dark matter (ΛCDM) cosmology by …
Synthesis of Molecular Oxygen via Irradiation of Ice Grains in the Protosolar Nebula
Wurz, P.; Lunine, J. I.; Danger, G. +4 more
Molecular oxygen has been detected in the coma of comet 67P/Churyumov-Gerasimenko with a mean abundance of 3.80 ± 0.85% by the ROSINA mass spectrometer on board the Rosetta spacecraft. To account for the presence of this species in comet 67P/Churyumov-Gerasimenko, it has been shown that the radiolysis of ice grain precursors of comets is a viable …
Hα Emitting Galaxies at z ∼ 0.6 in the Deep And Wide Narrow-band Survey
Mobasher, Bahram; Zheng, Zhen-Ya; Veilleux, Sylvain +14 more
We present new measurements of the Hα luminosity function (LF) and star formation rate (SFR) volume density for galaxies at z ∼ 0.62 in the COSMOS field. Our results are part of the Deep And Wide Narrow-band Survey (DAWN), a unique infrared imaging program with large areal coverage (∼1.1 deg2 over five fields) and sensitivity (9.9× {10}…