Search Publications
Prolonged, Weak C1.2 Flares: A Source of Protons and Electrons
Struminskii, A. B.; Grigor'eva, I. Yu.; Shakhovskaya, A. N.
Two proton events (>100 MeV; GOES, ACS SPI) associated with weak flares (C1.2, GOES class) in the soft X-ray range that occurred on November 26, 2011, and September 29, 2013, are analyzed. These events were accompanied by significant fluxes of relativistic electrons (>1 MeV; SOHO EPHIN) in the interplanetary space. The time profiles of these…
Emission-line Data Cubes of the HH 32 Stellar Jet
Hartigan, Patrick; Neill, James D.; Hillenbrand, Lynne A. +5 more
We analyze data cubes of over 60 emission lines in the HH 32 stellar jet acquired with the Keck Cosmic Web Imager (KCWI). The data cover the less explored blue portion of the spectrum between 3586 and 6351 Å and have both high spectral (R ∼ 10,000) and spatial (≲1″) resolution. The study includes all three major ionization states of oxygen, three …
Ionized gas in the NGC 5253 supernebula: high spatial and spectral resolution observations with the JVLA and TEXES
Beck, Sara C.; Liu, Hauyu Baobab; Ho, Paul T. P. +4 more
The youngest, closest, and most compact embedded massive star cluster known excites the supernebula in the nearby dwarf galaxy NGC 5253. It is a crucial target and test case for studying the birth and evolution of the most massive star clusters. We present observations of the ionized gas in this source with high spatial and spectral resolution. Th…
Swift/XRT, Chandra, and XMM-Newton observations of IGR J17091-3624 as it returns into quiescence
Court, J. M. C.; Altamirano, D.; Degenaar, N. +4 more
IGR J17091-3624 is a low-mass X-ray binary (LMXB), which received wide attention from the community thanks to its similarities with the bright black hole system GRS 1915+105. Both systems exhibit a wide range of highly structured X-ray variability during outburst, with time-scales from few seconds to tens of minutes, which make them unique in the …
A Survey of Venus Shock Crossings Dominated by Kinematic Relaxation
Pope, S. A.
Collisionless shocks are one of the most effective particle accelerators in the known universe. Even low Mach number shocks could have a significant role in particle heating and acceleration. Theory suggests that kinematic collisionless relaxation, the process whereby a downstream nongyroptopic ion population becomes thermalized through collisionl…
A spectroscopic, photometric, polarimetric, and radio study of the eclipsing polar UZ Fornacis: the first simultaneous SALT and MeerKAT observations
Hewitt, D. M.; Pretorius, M. L.; Woudt, P. A. +17 more
We present phase-resolved spectroscopy, photometry, and circular spectropolarimetry of the eclipsing polar UZ Fornacis. Doppler tomography of the strongest emission lines using the inside-out projection revealed the presence of three emission regions: from the irradiated face of the secondary star, the ballistic stream and the threading region, an…
The inner gas mass-temperature profile in the core of nearby galaxy clusters
Fabian, Andrew C.; Pinto, Ciro; Liu, Haonan
We present a mass-temperature profile of gas within the central 10 kpc of a small sample of cool core clusters. The mass of the hottest gas phases, at 1.5 and 0.7 keV, is determined from X-ray spectra from the XMM Reflection Grating Spectrometers. The masses of the partially ionized atomic and the molecular phases are obtained from published H α a…
The hydrogen Balmer lines and jump in absorption in accretion disc modelling - an ultraviolet-optical spectral analysis of the dwarf novae UZ Serpentis and CY Lyrae
Blair, William P.; Szkody, Paula; Sion, Edward M. +1 more
The spectra of disc-dominated cataclysmic variables (CVs) often deviate from the spectra of accretion disc models; in particular, the Balmer jump and absorption lines are found to be shallower in the observations than in the models. We carried out a combined ultraviolet-optical spectral analysis of two dwarf novae (DNe): UZ Ser in outburst, declin…
Variations in Ion-Component Pressure during Dipolarization in the Near-Earth Magnetotail Plasma Sheet
Malykhin, A. Yu.; Grigorenko, E. E.; Kronberg, E. A. +1 more
The dynamics of fluxes of thermal and suprathermal H+ and O+ ions and the pressure variations of these components during 11 events of magnetic field dipolarization in the plasma sheet of the geomagnetic tail are analyzed based on Cluster satellite observations. It was found that the energy of H+ and O+ i…
White-light solar corona structure observed by naked eye and processed images
Rušin, Vojtech; Prikryl, Paul; Prikryl, Emil A.
Light and dark adaptation and luminance contrast enhancement are well-known characteristics of human vision that allow us to observe a wide range of light intensity not fully captured in standard camera images. The naked-eye observations of total eclipses, some recorded with spectacular detail in artists' paintings, reveal structure that is consis…