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Revisiting the Evidence for an Intermediate-mass Black Hole in the Center of NGC 6624 with Simulations
Wang, Li-Chun; Xie, Yi
The acceleration of LMXB 4U 1820-30 derived from its orbital-period derivative ${\dot{P}}_{{\rm{b}}}$ was supposed to be the evidence for an Intermediate-mass black hole (IMBH) in the Galactic globular cluster (GC) NGC 6624. However, we find that the anomalous ${\dot{P}}_{{\rm{b}}}$ is mainly due to the gravitational wave emission, rather than the…
Gas Dynamics in the Star-forming Region G18.148-0.283: Is It a Manifestation of Two Colliding Molecular Clouds?
Dey, Jyotirmoy; Pandian, Jagadheep D.; Lal, Dharam Vir
We report the results obtained from a multiwavelength study of the H II region G18.148-0.283 using the upgraded Giant Metrewave Radio Telescope at 1350 MHz, along with other archival data. In addition to the radio continuum emission, we have detected the H169α and H170α radio recombination lines toward G18.148-0.283 using a correlator bandwidth of…
The nature of the X-ray sources constituting the 6.7 keV Galactic ridge emission
Schmitt, J. H. M. M.; Czesla, S.; Robrade, J. +2 more
We reanalyze the deep Chandra X-ray observations near the Galactic center and show that reliable identifications of X-ray sources can be obtained with the Gaia EDR3 data to investigate which types of stellar sources are responsible for the X-ray emission observed from the Galactic ridge (GRXE). In the central 3 arcmin region 318 X-ray sources are …
Kinematic Structure of the Milky Way Galaxy, Near the Spiral Arm Tangents
Vallée, Jacques P.
We compare the observed radial velocity of different arm tracers, taken near the tangent to a spiral arm. A slight difference is predicted by the density wave theory, given the shock predicted at the entrance to the inner spiral arm. In many of these spiral arms, the observed velocity offset confirms the prediction of the density wave theory (with…
The Expansion of the X-Ray Nebula Around η Car
Corcoran, Michael F.; Russell, C. M. P.; Hamaguchi, K. +8 more
The massive colliding wind binary system η Car is embedded in an X-ray emitting region having a characteristic temperature of a few million degrees, associated with ejecta produced during the 1840s, and in earlier outbursts. We use CHANDRA X-ray imaging observations obtained over the past two decades to directly measure the expansion of the X-ray …
The Warm Gas in the Milky Way: The Kinematical Model of C IV and Its Connection to Si IV
Bregman, Joel N.; Qu, Zhijie; Lindley, Ryan
We compose a 265-sight-line Milky Way C IV line-shape sample using the Hubble Space Telescope/Cosmic Origins Spectrograph archive, which is complementary to the existing Si IV samples. C IV has a higher ionization potential (47-64 eV) than Si IV (33-45 eV), so it also traces warm gas, which is roughly cospatial with Si IV. The spatial density dist…
First photometric and orbital period investigations of the total-eclipse contact binary V0339 Com
Yu, Yun-Xia; Hu, Ke; Xiang, Fu-Yuan +2 more
We presented the first photometric and orbital period investigation for the W UMa-type binary V0339 Com. The multi-bands light curves were obtained and analyzed with the Wilson-Devinney Code. The photometric solutions suggested that V0339 Com is an A-subtype shallow contact binary with a degree of contact f = 12 . 0% . The total eclipse of V0339 C…
Cyanopolyyne line survey towards high-mass star-forming regions with TMRT
Wang, Y. X.; Zhang, J. S.; Yan, Y. T. +8 more
Context. Cyanopolyynes (HC2n+1 N, n = 1,2,3), which are the linear carbon chain molecules, are precursors for the prebiotic synthesis of simple amino acids. They are important for understanding prebiotic chemistry and may be good tracers of the star formation sequence.
Aims: We aim to search for cyanopolyynes in high-mass star-form…
Uranus's and Neptune's Stratospheric Water Abundance and Vertical Profile from Herschel-HIFI
Irwin, P. G. J.; Teanby, N. A.; Nixon, C. A. +2 more
Here we present new constraints on Uranus's and Neptune's externally sourced stratospheric water abundance using disk-averaged observations of the 557 GHz emission line from Herschel's Heterodyne Instrument for the Far-Infrared. Derived stratospheric column water abundances are × 1014 cm‑2 for Uranus and ×1014 cm
Precise Positions of Triton in 2010-2014 based on Gaia-DR2
Yu, Yong; Tang, Kai; Zhang, Huiyan +2 more
With unique orbital and physical characteristics, Triton is a very important target because it may contain information of the origin and evolution of the solar system. Besides space explorations, ground-based observations over long time also play a key role on research of Triton. High-precision positions of Triton obtained from ground telescopes a…