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Optical Identification of Four Hard X-ray Sources from the INTEGRAL Sky Surveys
Medvedev, P. S.; Sazonov, S. Yu.; Eselevich, M. V. +8 more
We continue the study begun in Karasev et al. (2018) and present the results of our optical identifications of four hard X-ray sources from the INTEGRAL sky surveys. Having first improved the positions of these objects in the sky with the X-ray telescope (XRT) of the Swift observatory, we have identified their counterparts using optical and infrar…
Follow-up Ground-based Observations of the Dwarf Nova KZ Gem
Thorstensen, John R.; Szkody, Paula; Dai, Zhibin +1 more
We present spectroscopy of stars in the immediate vicinity of the dwarf nova (DN) KZ Gem to confirm its identification, which is ambiguous in the literature. Analysis of 73 radial velocities spanning from 2014 to 2019 provides a high-precision orbital period of 0.2224628(2) days (∼5.34 hr) and shows KZ Gem to be a double-lined DN. Time series phot…
SMA observations of Haro 2: molecular gas around a hot superbubble
Beck, Sara C.; Hsieh, Pei-Ying; Turner, Jean
Haro 2, a nearby dwarf starburst dwarf galaxy with strong Ly α emission, hosts a starburst that has created outflows and filaments. The clear evidence for galactic outflow makes it an ideal candidate for studying the role of molecular gas in feedback processes in a dwarf galaxy. We observed CO(2-1) in Haro 2 at the Submillimeter Array in the compa…
Dayside-to-nightside dust coma brightness asymmetry and its implications for nightside activity at Comet 67P/Churyumov-Gerasimenko
Thomas, N.; Marschall, R.; Wu, J. -S. +2 more
We have determined the dust coma brightness ratio between the dayside and the nightside (DS:NS) in OSIRIS images of comet 67P/Churyumov-Gerasimenko and compared them to results from numerical dust coma simulations to learn more about the dynamic processes that are involved in coma formation. The primary focus of this paper lies in the analysis of …
Insights from multi-wavelength observations during high and low states of non-magnetic CVs
Szkody, Paula
Close binaries containing a white dwarf accreting from a disk that receives material from a late stellar companion show an interesting variety of behaviors that depend on their accretion rates and the changes in this rate. The highest accretion rates are evident during the bright states of novalikes, as well as the superoutbursts of the shortest p…
NLTE spectral analysis of the intermediate helium-rich subdwarf B star CPD-20°1123
Löbling, L.
Subdwarf B (sdB) stars are core helium-burning stars with stratified atmospheres. Their atmospheres are dominated by hydrogen (H) while the helium (He) and metal abundances are shaped by an interplay of gravitational settling and radiative levitation. However, a small fraction of these show spectra dominated by He I absorption lines. In between th…
Cross-correlating Planck with VST ATLAS LRGs: a new test for the ISW effect in the Southern hemisphere
Metcalfe, Nigel; Shanks, Tom; Ansarinejad, Behzad +1 more
The integrated Sachs-Wolfe (ISW) effect probes the late-time expansion history of the Universe, offering direct constraints on dark energy. Here, we present our measurements of the ISW signal at redshifts of $\bar{z}=0.35$ , 0.55, and 0.68, using the cross-correlation of the Planck cosmic microwave background temperature map with ∼0.5 million lumi…
Observation of Disturbed Plasma Structures in the Environment of the Sun and Near-Earth Space with Radio Sounding and Local Measurements
Bird, M. K.; Efimov, A. I.; Lukanina, L. A. +3 more
An experiment on radio sounding of the circumsolar plasma by signals from the Mars Express spacecraft in 2013 was carried out in the period from March 4 through May 31. The investigated characteristics were the frequency of signals in the centimeter and decimeter ranges and the differential frequency. A number of events were recorded in which the …
New CCD photometry and light curve analysis of two WUMaBinaries: 1SWASP J133417.80+394314.4 and V2790 Orion
El-Depsey, M. H.; Hassan, I. A.; Shokry, A. +5 more
We present a new multicolor CCD photometry and light curve analysis of two eclipsing binary systems, 1SWASP J133417.80 + 394314.4 and V2790 Orion. The photometric solutions for both binaries were carried out using the updated version of the Wilson- Devinney code. The results showed that first systems is A- type W UMa with mass ratios q = 0.158 whi…
Accuracy of magnitudes in pre‑telescopic star catalogs
Hoffmann, Susanne M.; Protte, Philipp
Historical star magnitudes from catalogs by Ptolemy (137 AD), al‑Sūfī (964), and Tycho Brahe (1602/27) are converted to the Johnson V‑mag scale and compared to modern‑day values from the HIPPARCOS catalog. The deviations (or "errors") are tested for dependencies on three different observational influences. The relation between historical and moder…