Search Publications
Luminosity Function and Event Rate Density of XMM-Newton-selected Supernova Shock Breakout Candidates
Liu, Zhu; Yuan, Weimin; Sun, Hui +6 more
A dozen X-ray supernova shock breakout (SN SBO) candidates were reported recently based on XMM-Newton archival data, which increased the X-ray-selected SN SBO sample by an order of magnitude. Assuming that they are genuine SN SBOs, we study the luminosity function (LF) by improving on the method used in our previous work. The light curves and the …
Light from the Darkness: Detecting Ultra-diffuse Galaxies in the Perseus Cluster through Over-densities of Globular Clusters with a Log-Gaussian Cox Process
van Dokkum, Pieter; Romanowsky, Aaron J.; Abraham, Roberto +6 more
We introduce a new method for detecting ultra-diffuse galaxies by searching for over-densities in intergalactic globular cluster populations. Our approach is based on an application of the log-Gaussian Cox process, which is a commonly used model in the spatial statistics literature but rarely used in astronomy. This method is applied to the globul…
The impact of stellar clustering on the observed multiplicity of super-earth systems: outside-in cascade of orbital misalignments initiated by stellar flybys
Rodet, Laetitia; Lai, Dong
A recent study suggests that the observed multiplicity of super-Earth (SE) systems is correlated with stellar overdensities: field stars in high phase-space density environments have an excess of single-planet systems compared to stars in low-density fields. This correlation is puzzling as stellar clustering is expected to influence mostly the out…
A detailed comparison of techniques used to model drift in numerical cosmic ray modulation models
Ferreira, S. E. S.; Engelbrecht, N. Eugene; Mohlolo, S. T.
Drifts have long been known to play a significant role in the transport and modulation of galactic cosmic rays (GCRs), occurring due to gradients in, as well as the curvature of, the heliospheric magnetic field (HMF). GCRs also drift along the wavy current sheet, a structure separating regions of opposite HMF polarity. Furthermore, the influence o…
Improved hydrodynamic pulsation models for the pulsating extreme helium star V652 Herculis
Saio, Hideyuki; Jeffery, C. Simon; Montañés-Rodríguez, Pilar
New non-linear hydrodynamic models have been constructed to simulate the radial pulsations observed in the extreme helium star V652 Her. These use a finer zoning to allow higher radial resolution than in previous simulations. Models incorporate updated OPAL and OP opacity tables and adopt a composition based on the best atmospheric analyses to dat…
Doubling of minute-long quasi-periodic pulsations from super-flares on a low-mass star
Ramsay, Gavin; Irawati, Puji; Dhillon, Vik S. +5 more
Using the ULTRASPEC instrument mounted on the 2.4-m Thai National Telescope, we observed two large flares, each with a total energy close to 1034 erg with sub-second cadence. A combination of a wavelet analysis, a Fourier transform plus an empirical mode decomposition, reveals quasi-periodic pulsations (QPPs) that exhibit an apparent do…
On the nature of the X-ray pulsar XTE J1859+083 and its broad-band properties
Gromadzki, Mariusz; Buckley, David A. H.; Tsygankov, Sergey S. +5 more
This work is devoted to the study of the broad-band 0.8-79 keV spectral and timing properties of the poorly studied X-ray pulsar XTE J1859+083 during its 2015 outburst based on the data from the NuSTAR and Swift observatories. We show that the source pulse profile has complex shape that depends on the energy band. Pulse fraction of XTE J1859+083 h…
The Solar Wind Parker Spiral Angle Distributions and Variations at 1 au
Xu, Qi; Xu, Xiaojun; Wang, Jing +8 more
Using the data from the Advanced Composition Explorer (ACE) and Wind spacecraft, we statistically studied the Parker spiral angle (PSA) of the solar wind magnetic field from 1998 to 2019 at 1 au. The PSA occurrences over both a Carrington rotation (CR) and a year can be well fitted by a Gaussian distribution. However, large-scale magnetic structur…
Massive Multi-Mission Statistical Study and Analytical Modeling of the Earth's Magnetopause: 4. On the Near-Cusp Magnetopause Indentation
Lavraud, B.; Jeandet, A.; Aunai, N. +3 more
The shape and location of the magnetopause current sheet in the near-cusp region is still a debated question. Over time, several observations led to contradictory conclusions regarding the presence of an indentation of the magnetopause in that region. As a result several empirical models consider the surface is indented in that region, while some …
Searching Extra-tidal Features around the Globular Cluster Whiting 1
Tian, Haijun; Tian, Hao; Carballo-Bello, Julio A. +14 more
Whiting 1 is a faint and young globular cluster in the halo of the Milky Way, and was suggested to have originated in the Sagittarius spherical dwarf galaxy (Sgr dSph). In this paper, we use the deep DESI Legacy Imaging Surveys to explore tentative spatial connection between Whiting 1 and the Sgr dSph. We redetermine the fundamental parameters of …