Search Publications
Calcium Bright Knots and the Formation of Chromospheric Anemone Jets on the Sun
Shibata, Kazunari; Singh, Kunwar Alkendra Pratap; Nishida, Keisuke
Space-based observations show that the solar atmosphere from the solar chromosphere to the solar corona is filled with small-scale jets and is linked with small-scale explosions. These jets may be produced by mechanisms similar to those of large-scale flares and such jets may be related to the heating of the corona and chromosphere as well as the …
The HST Large Programme on ω Centauri: VII. The white dwarf cooling sequence
Salaris, M.; Apai, D.; Anderson, J. +9 more
We present a study of the white dwarf (WD) cooling sequence (CS) in the globular cluster (GC) Omega Centauri (or NGC 5139; hereafter, ω Cen), the primary goal of a dedicated Hubble Space Telescope (HST) programme. We find that the peak at the termination of the WD CS is located at mF606W = 30.1 ± 0.2 (equivalent to V ∼ 31). The brighter…
Evidence of the γ-ray counterpart of nova FM Cir from Fermi-LAT
Takata, J.; Wang, H. H.; Lin, L. C. -C. +2 more
We report the results of an analysis of X-ray and γ-ray data from the nova FM Cir taken by Swift and Fermi-LAT. The γ-ray emission from FM Cir can be identified with a significance level of ~3σ within ~40 d after the nova eruption (2018 January 19) when we bin the light curve per day. The significance can exceed the 4σ confidence level if we accum…
Physical Parameters and Magnetic Activity of M-type Stars Based on the LAMOST DR9, SDSS, and TESS Surveys
Han, Xianming L.; Misra, Prabhakar; Zhang, Li-yun +3 more
We analyze a catalog comprising 781,232 spectra from 641,095 M dwarf stars from the Large Sky Area Multi-Object Fiber Spectroscopic Telescope (LAMOST) low-resolution spectroscopic data release 9. Based on the equivalent width of the Hα line, we ascertain the activity properties of the stars, identifying a total of 107,134 active stars, with 31,175…
Geomagnetic Pulsations in the 1-4 mHz Frequency Range (Pc5/Pi3) in the Magnetotail. Internal and Extramagnetospheric Sources
Yagova, N. V.; Evsina, N. S.
Spectral and spatial parameters of nonstorm Pc5/Pi3 geomagnetic pulsations in the geomagnetic tail are studied based on magnetic measurements on Cluster satellites under different conditions in the interplanetary medium. Both the average values of the magnetic field components in front of the bow shock and fluctuations in the pulsations' frequency…
Possible anticorrelations between pulsation amplitudes and the disc growth of Be stars in giant-outbursting Be X-ray binaries
Soria, Roberto; Ricker, George R.; Vanderspek, Roland +15 more
The mechanism of X-ray outbursts in Be X-ray binaries remains a mystery, and understanding their circumstellar discs is crucial for a solution of the mass-transfer problem. In particular, it is important to identify the Be star activities (e.g. pulsations) that cause mass ejection and, hence, disc formation. Therefore, we investigated the relation…
Distinguishing exoplanet companions from field stars in direct imaging using Gaia astrometry
Bailer-Jones, Coryn A. L.; Samland, Matthias; Herz, Philipp
Direct imaging searches for exoplanets around stars detect many spurious candidates that are in fact background field stars. To help distinguish these from genuine companions, multi-epoch astrometry can be used to identify a common proper motion with the host star. Although this is frequently done, many approaches lack an appropriate model for the…
Probing ultralight isospin-violating mediators at GW170817
Liu, Zuowei; Tang, Zi-Wei
Gravitational wave (GW) signals arising from binary neutron star mergers offer new, sensitive probes to ultralight mediators. Here we analyze the GW signals in the GW170817 event detected by the LIGO/Virgo collaboration to impose constraints on the ultralight isospin-violating mediator that has different couplings to protons and neutrons. Neutron …
Bidirectional propagating brightenings in arch filament systems observed by Solar Orbiter/EUI
Chen, Yajie; Peter, Hardi; Chitta, Lakshmi Pradeep +1 more
Arch filament systems (AFSs) are chromospheric and coronal manifestations of emerging magnetic flux. Using high spatial resolution observations taken at a high cadence by the Extreme Ultraviolet Imager (EUI) on board Solar Orbiter, we identified small-scale elongated brightenings within the AFSs. These brightenings appear as bidirectional flows al…
Has the Palomar 14 Globular Cluster Been Captured by the Milky Way?
Kroupa, Pavel; Haghi, Hosein; Zonoozi, Akram Hasani +1 more
We examine a new scenario to model the outer halo globular cluster (GC) Palomar 14 (Pal 14) over its lifetime by performing a comprehensive set of direct N-body calculations. We assume Pal 14 was born in a now detached/disrupted dwarf galaxy with a strong tidal field. Pal 14 evolved there until the slope of the stellar mass function (MF) became cl…