Search Publications
Wavelet analysis of low frequency plasma oscillations in the magnetosheath of Mars
Fränz, M.; Bolzan, M. J. A.; Echer, E. +1 more
Wavelet analysis was employed to identify the major frequencies present in the plasma oscillations in the Martian magnetosheath. We have selected magnetosheath crossings and applied the Morlet wavelet transform to the electron density and temperature data, obtained from the Analyzer of Space Plasmas and Energetic Atoms experiment (ASPERA-3), onboa…
Long-period High-amplitude Red Variables in the KELT Survey
Pepper, Joshua; Stassun, Keivan G.; Siverd, Robert J. +8 more
We present a sample of 4132 Mira-like variables (red variables with long periods and high amplitudes) in the Kilodegree Extremely Little Telescope (KELT) survey. Of these, 376 are new Mira-like detections. We used Two Micron All Sky Survey (2MASS) colors to identify candidate asymptotic giant branch stars. We searched for photometric variability a…
The unusual behavior of the young X-ray pulsar SXP 1062 during the 2019 outburst
Maitra, Chandreyee; Haberl, Frank; Doroshenko, Victor +6 more
We present the results of the first dedicated observation of the young X-ray pulsar SXP 1062 in the broad X-ray energy band obtained during its 2019 outburst with the NuSTAR and XMM-Newton observatories. The analysis of the pulse-phase averaged and phase-resolved spectra in the energy band from 0.5 to 70 keV did not reveal any evidence for the pre…
Automatic catalog of RR Lyrae from ∼14 million VVV light curves: How far can we go with traditional machine-learning?
Gurovich, S.; Cabral, J. B.; Granitto, P. M. +1 more
Context. The creation of a 3D map of the bulge using RR Lyrae (RRL) is one of the main goals of the VISTA Variables in the Via Lactea Survey (VVV) and VVV(X) surveys. The overwhelming number of sources undergoing analysis undoubtedly requires the use of automatic procedures. In this context, previous studies have introduced the use of machine lear…
Peak Temperatures of Large Solar X-Ray Flares and Associated CME Speeds and Widths
Kahler, S. W.; Ling, A. G.
We recently repeated an earlier analysis by Garcia showing that large (≥M3.0) solar X-ray flares associated with solar energetic particle (SEP) events have significantly lower peak X-ray flux ratios R = (0.04-0.5 nm)/(0.1-0.8 nm), proxies for flare peak temperatures, than those without SEP events. As we expect SEP events to be produced by shocks a…
A Mean Density of 112 M⊙ pc-3 for Central Molecular Zone Clumps—Evidences for Shear-enabled Pressure Equilibrium in the Galactic Center
Zhang, Chuan-Peng; Li, Guang-Xing
We carry out a systematic study of the density structure of gas in the Central Molecular Zone (CMZ) in the Galactic center by extracting clumps from the APEX Telescope Large Area Survey of the Galaxy survey at 870 µm. We find that the clumps follow a scaling of m = ρ0r3, which corresponds to a characteristic density of …
Hot gas heating via magnetic arms in spiral galaxies. The case of M 83
Ehle, M.; Weżgowiec, M.; Soida, M. +3 more
Context. Reconnection heating has been considered as a potential source of the heating of the interstellar medium. In some galaxies, significant polarised radio emission has been found between the spiral arms. This emission has a form of "magnetic arms" that resembles the spiral structure of the galaxy. Reconnection effects could convert some of t…
A Dust Trap in the Young Multiple System HD 34700
Wilner, David J.; Zhang, Qizhou; Rich, Evan A. +6 more
Millimeter observations of disks around young stars reveal substructures indicative of gas pressure traps that may aid grain growth and planet formation. We present Submillimeter Array observations of HD 34700: two Herbig Ae stars in a close binary system (Aa/Ab, ∼0.25 au), surrounded by a disk presenting a large cavity and spiral arms seen in sca…
A search for the modern counterparts of the Far Eastern guest stars 369 CE, 386 CE and 393 CE
Hoffmann, Susanne M.; Vogt, Nikolaus
In this study, we apply our previously developed method to investigate ancient transient sightings in order to derive consequences for modern astrophysical problems. We present case studies of three observations of so-called guest stars in the fourth century CE, which lasted several months each. These three observations had been discussed and sugg…
A Model of the Dust Envelope of the Carbon Mira Star V CrB from Photometry, Infrared Spectroscopy, and Speckle Polarimetry
Safonov, B. S.; Tatarnikov, A. M.; Shenavrin, V. I. +2 more
$UBVJHKLM$ photometry for the carbon Mira star V CrB are presented. The infrared observations were carried out in the time interval 1989-2018, while the $U$, $B$, and $V$ data were obtained in 2001-2014. The light and color curves are analyzed. The pulsation period of V CrB has been found to be $355\overset{\textrm{d}}{.}2$ in the infrared $JHKLM$…