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NGC 1605a and NGC 1605b: An Old Binary Open Cluster in the Galaxy
Camargo, Denilso
This work communicates the discovery of a binary open cluster within the Galaxy. NGC 1605 presents an unusual morphology with a sparse stellar distribution and a double core in close angular proximity. The 2MASS and Gaia-EDR3 field-star decontaminated color-magnitude diagrams (CMDs) show two distinct stellar populations located at the same helioce…
Revised Surface Abundances of R Coronae Borealis Stars
Reddy, Arumalla B. S.; Pandey, Gajendra; Hema, B. P.
Surface abundances of 14 (11 majority class and three minority class) R Coronae Borealis stars (RCBs) along with the final-flash object, V4334 Sgr (Sakurai's object) are revised based on their carbon abundances measured from the observed C2 bands; note that the earlier reported abundances were derived using an assumed carbon abundance d…
Relativistic Reflection in NGC 4151
Zdziarski, Andrzej A.; Szanecki, Michał; Niedźwiecki, Andrzej
We investigate the X-ray spectrum of the Seyfert galaxy NGC 4151 using the simultaneous Suzaku/NuSTAR observation and flux-resolved INTEGRAL spectra supplemented by Suzaku and XMM observations. Our best spectral solution indicates that the narrow Fe Kα line is produced in Compton-thin matter at a distance of several hundred gravitational radii. In…
A Possible Kilonova Powered by Magnetic Wind from a Newborn Black Hole
Liu, Yu; Zhang, Bin-Bin; Lü, Hou-Jun +4 more
The merger of binary neutron stars (NS-NS) as the progenitor of short gamma-ray bursts (GRBs) has been confirmed by the discovery of the association of the gravitational-wave (GW) event GW170817 with GRB 170817A. However, the merger product of binary NS remains an open question. An X-ray plateau followed by a steep decay ("internal plateau") has b…
The Heating and Pulsations of V386 Serpentis after Its 2019 Dwarf Nova Outburst
Bell, Keaton J.; Szkody, Paula; Sion, Edward M. +10 more
Following the pulsation spectrum of a white dwarf through the heating and cooling involved in a dwarf nova outburst cycle provides a unique view of the changes to convective driving that take place on timescales of months versus millennia for nonaccreting white dwarfs. In 2019 January the dwarf nova V386 Ser (one of a small number containing an ac…
Complexity of Magnetic-field Turbulence at Reconnection Exhausts in the Solar Wind at 1 au
Miranda, Rodrigo A.; Valdivia, Juan A.; Chian, Abraham C. -L. +1 more
Magnetic reconnection is a complex mechanism that converts magnetic energy into particle kinetic energy and plasma thermal energy in space and astrophysical plasmas. In addition, magnetic reconnection and turbulence appear to be intimately related in plasmas. We analyze the magnetic-field turbulence at the exhaust of four reconnection events detec…
Discovery of a Low-redshift Damped Lyα System in a Foreground Extended Disk Using a Starburst Galaxy Background Illuminator
Heckman, Timothy M.; Alexandroff, Rachael M.; Jansen, Rolf A. +3 more
We present the discovery of a low-redshift damped Lyα (DLA) system in the spectrum of background starburst galaxy SDSS J111323.88+293039.3 (z = 0.17514). The DLA is at an impact parameter of ρ = 36 kpc from the star-forming galaxy, SDSS J111324.08+293051.2 (z = 0.17077). We measure an H column density of N(H ) = 3.47 × 1020 cm-2
Investigation of the Physical Origin of Overionized Recombining Plasma in the Supernova Remnant IC 443 with XMM-Newton
Seta, Masumichi; Uchida, Hiroyuki; Tsuru, Takeshi Go +4 more
The physical origin of the overionized recombining plasmas (RPs) in supernova remnants (SNRs) has been attracting attention because its understanding provides new insight into SNR evolution. However, the process of the overionization, although it has been discussed in some RP-SNRs, is not yet fully understood. Here, we report on spatially resolved…
Magnetic Connections across the Chromosphere-Corona Transition Region
Judge, Philip
The plasma contributing to emission from the Sun between the cool chromosphere (≤104 K) and hot corona (≥106 K) has been subjected to many different interpretations. Here we look at the magnetic structure of this transition region (TR) plasma, based upon the implications of CLASP2 data of an active region recently published b…
The Nature of the Eccentric Double-lined Eclipsing Binary System KIC 2306740 with Kepler Space Photometry
Southworth, J.; Koçak, D.; Yakut, K. +4 more
We present a detailed study of KIC 2306740, an eccentric double-lined eclipsing binary system. Kepler satellite data were combined with spectroscopic data obtained with the 4.2 m William Herschel Telescope (WHT). This allowed us to determine precise orbital and physical parameters of this relatively long period (P = 10.3°) and slightly eccentric (…