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Hot Subdwarf All Southern Sky Fast Transit Survey with the Evryscope
Law, Nicholas M.; Németh, Péter; Glazier, Amy +6 more
We have conducted a survey of candidate hot subdwarf (HSD) stars in the southern sky searching for fast transits, eclipses, and sinusoidal-like variability in the Evryscope light curves. The survey aims to detect transit signals from Neptune-size planets to gas giants, and eclipses from M-dwarfs and brown dwarfs. The other variability signals are …
The discovery of lambda Bootis stars - the Southern Survey II
Bedding, Timothy R.; Murphy, Simon J.; Gray, Richard O. +3 more
The λ Boo stars are chemically peculiar A-type stars whose abundance anomalies are associated with the accretion of metal-poor material. We searched for λ Boo stars in the Southern hemisphere in a targeted spectroscopic survey of metal-weak and emission-line stars. Obtaining spectra for 308 stars and classifying them on the MK system, we found or …
Comparison of simulated backgrounds with in-orbit observations for HE, ME, and LE onboard Insight-HXMT
Li, Gang; Li, Xiaobo; Tuo, Youli +10 more
Insight-HXMT, the first X-ray astronomical satellite in China, aims to reveal new sources in the Galaxy and to study fundamental physics of X-ray binaries from 1 to 250 keV. It has three collimated telescopes, the High Energy X-ray telescope (HE), the Medium Energy X-ray telescope (ME), and the Low Energy X-ray telescope (LE). Before the launch, i…
Searching for the near-infrared counterpart of Proxima c using multi-epoch high-contrast SPHERE data at VLT
Ménard, F.; Henning, T.; Brandner, W. +43 more
Context. Proxima Centauri is the closest star to the Sun and it is known to host an Earth-like planet in its habitable zone; very recently a second candidate planet was proposed based on radial velocities. At quadrature, the expected projected separation of this new candidate is larger than 1 arcsec, making it a potentially interesting target for …
Jupiter's X-ray Emission During the 2007 Solar Minimum
Jackman, C. M.; Paranicas, C.; Ness, J. -U. +22 more
The 2007-2009 solar minimum was the longest of the space age. We present the first of two companion papers on Chandra and XMM-Newton X-ray campaigns of Jupiter through February-March 2007. We find that low solar X-ray flux during solar minimum causes Jupiter's equatorial regions to be exceptionally X-ray dim (0.21 GW at minimum; 0.76 GW at maximum…
Chandra and XMM-Newton observations of A2256: cold fronts, merger shocks, and constraint on the IC emission
Rudnick, Lawrence; Finoguenov, Alexis; Clarke, Tracy E. +13 more
We present the results of deep Chandra and XMM-Newton observations of a complex merging galaxy cluster Abell 2256 (A2256) that hosts a spectacular radio relic (RR). The temperature and metallicity maps show clear evidence of a merger between the western subcluster (SC) and the primary cluster (PC). We detect five X-ray surface brightness edges. Th…
A new radio catalogue for M83: supernova remnants and H II regions
Soria, Roberto; White, Richard L.; Blair, William P. +3 more
We present a new catalogue of radio sources in the face-on spiral galaxy M83. Radio observations taken in 2011, 2015, and 2017 with the Australia Telescope Compact Array at 5.5 and 9 GHz have detected 270 radio sources. Although a small number of these sources are background extragalactic sources, most are either H II regions or supernova remnants…
A giant galaxy in the young Universe with a massive ring
Kacprzak, Glenn G.; Glazebrook, Karl; Labbé, Ivo +12 more
In the local (redshift z ≈ 0) Universe, collisional ring galaxies make up only ~0.01% of galaxies1 and are formed by head-on galactic collisions that trigger radially propagating density waves2-4. These striking systems provide key snapshots for dissecting galactic disks and are studied extensively in the local Universe5…
A novel approach for optimal trajectory design with multiple operation modes of propulsion system, part 2
Taheri, Ehsan; Junkins, John L.; Kolmanovsky, Ilya +1 more
Equipping a spacecraft with multiple solar-powered electric engines (of the same or different types) compounds the task of optimal trajectory design due to presence of both real-valued inputs (power input to each engine in addition to the direction of thrust vector) and discrete variables (number of active engines). Each engine can be switched on/…
On the Production of He+ of Solar Origin in the Solar Wind
Landi, Enrico; Rivera, Yeimy J.; Lepri, Susan T. +1 more
Solar wind measurements in the heliosphere predominantly comprise protons, alphas, and minor elements in a highly ionized state. The majority of low-charge states, such as He+, measured in situ are often attributed to pick-up ions of nonsolar origin. However, through inspection of the velocity distribution functions of near-Earth measur…