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Applying wavelet analysis to the X-ray light curves of active galactic nuclei and quasi-periodic eruptions
Gallo, L. C.; Gonzalez, A. G.; Ghosh, Akshay
In this work, we examine the application of the wavelet transform to the X-ray timing analyses of active galactic nuclei (AGN) and quasi-periodic eruption sources (QPEs). Several scenarios are simulated to test the effectiveness of the wavelet analysis to stationary and non-stationary data. We find that the power spectral density (PSD) slope and t…
Accelerated Structural Evolution of Galaxies in a Starbursting Cluster at z = 2.51
Daddi, Emanuele; Lu, Shiying; Elbaz, David +11 more
Structural properties of cluster galaxies during their peak formation epoch, z ~ 2-4 provide key information on whether and how the environment affects galaxy formation and evolution. Based on deep Hubble Space Telescope (HST)/Wide Field Camera 3 (WFC3) imaging toward the z = 2.51 cluster, J1001, we explore environmental effects on the structure, …
An advanced thermal roughness model for airless planetary bodies. Implications for global variations of lunar hydration and mineralogical mapping of Mercury with the MERTIS spectrometer
Hiesinger, Harald; Helbert, Jörn; Wöhler, Christian +1 more
We present a combined reflectance and thermal radiance model for airless planetary bodies. The Hapke model provides the reflected component. The developed thermal model is the first to consistently use rough fractal surfaces, self-scattering, self-heating, and disk-resolved bolometric albedo for entire planets. We validated the model with disk-res…
The spatial correlation of high-mass X-ray binaries and young star clusters in nearby star-forming galaxies
Williams, Benjamin F.; Binder, Breanna A.; Lazzarini, Margaret +2 more
We present an analysis of the two-point spatial correlation functions of high-mass X-ray binary (HMXB) and young star cluster (YSC) populations in M31 and M33. We find evidence that HMXBs are spatially correlated with YSCs to a higher degree than would be expected from random chance in both galaxies. When supplemented with similar studies in the M…
Excitation of Saturnian ECH Waves Within Remote Plasma Injections: Cassini Observations
Ni, Binbin; Gu, Xudong; Cao, Xing +7 more
Based on Cassini observations, we report representative electrostatic electron cyclotron harmonic (ECH) wave events observed in Saturn's magnetosphere within remote plasma injections. Unlike local injections, remote injections are "older" injection events that have evolved to form a dispersed signature in particle energy spectrum. We show that Sat…
Global Energetics of Solar Powerful Events on 2017 September 6
Lu, Lei; Dresing, Nina; Wang, Jincheng +9 more
Solar flares and coronal mass ejections (CMEs) are thought to be the most powerful events on the Sun. They can release energy as high as ~1032 erg in tens of minutes, and also can release solar energetic particles (SEPs) into interplanetary space. We explore global energy budgets of solar major eruptions that occurred on 2017 September …
A LOFAR sample of luminous compact sources coincident with nearby dwarf galaxies
Shimwell, T. W.; Vedantham, H. K.; Kaplan, D. L. +5 more
The vast majority of extragalactic compact continuum radio sources are associated with star formation or jets from (super)massive black holes and, as such, are more likely to be found in association with starburst galaxies or early-type galaxies. Two new populations of radio sources were recently identified: (a) compact and persistent sources (PRS…
Strongest Coronal Magnetic Fields in Solar Cycles 23 and 24: Probing, Statistics, and Implications
Fleishman, Gregory D.; Anfinogentov, Sergey A.; Fedenev, Viktor V.
A strong coronal magnetic field, when present, manifests itself as bright microwave sources at high frequencies produced by the gyroresonant (GR) emission mechanism in thermal coronal plasma. The highest frequency at which this emission is observed is proportional to the absolute value of the strongest coronal magnetic field on the line of sight. …
The variable source of the plasma sheet during a geomagnetic storm
Asamura, K.; Kistler, L. M.; Mouikis, C. G. +8 more
Both solar wind and ionospheric sources contribute to the magnetotail plasma sheet, but how their contribution changes during a geomagnetic storm is an open question. The source is critical because the plasma sheet properties control the enhancement and decay rate of the ring current, the main cause of the geomagnetic field perturbations that defi…
Interaction of a coronal mass ejection and a stream interaction region: A case study
Geyer, Paul; Dumbović, Mateja; Temmer, Manuela +3 more
We investigated the interaction of a coronal mass ejection (CME) and a coronal hole (CH) in its vicinity using remote-sensing and 1 AU in situ data. We used extreme-ultraviolet images and magnetograms to identify coronal structures and coronagraph images to analyze the early CME propagation. The Wind spacecraft and the Advanced Composition Explore…