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An intriguing globular cluster in the Galactic bulge from the VVV survey
Minniti, D.; Saito, R. K.; Alonso-García, J. +7 more
Context. Globular clusters (GCs) are the oldest objects known in the Milky Way, so each discovery of a new GC is astrophysically important. In the inner Galactic bulge regions these objects are difficult to find due to extreme crowding and extinction. However, recent near-IR surveys have discovered a number of new bulge GC candidates that need to …
Formation of Multiple Populations of M5 (NGC 5904)
Lee, Jae-Woo
With our new Ca-CN-CH-NH photometry, we revisit the globular cluster (GC) M5. We find that M5 is a mono-metallic GC with a small metallicity dispersion. Our carbon abundances show that the σ[C/Fe] of the M5 CN-s population, with depleted carbon and enhanced nitrogen abundances, is significantly large for a single stellar population. Our new analys…
Tracing the Origin of Moving Groups. III. Detecting Moving Groups in LAMOST DR7
Zhao, Gang; Yang, Yong; Zhao, Jingkun +2 more
We revisit the moving groups (MGs) in the solar neighborhood with a sample of 91,969 nearby stars constructed from LAMOST DR7. Using the wavelet technique and Monte Carlo simulations, five MGs together with a new candidate located at V≃-130 km s-1 are detected simultaneously in $V-\sqrt{{U}^{2}+2{V}^{2}}$ space. Taking into account the …
Resolving the Circumstellar Environment of the Galactic B[e] Supergiant Star MWC 137.II. Nebular Kinematics and Stellar Variability
Liimets, Tiina; Kraus, Michaela; Jones, David +4 more
The Galactic B[e] supergiant MWC 137 is surrounded by a large-scale optical nebula. To shed light on the physical conditions and kinematics of the nebula, we analyze the optical forbidden emission lines [N II] λλ 6548,6583 and [S II] λλ 6716,6731 in long-slit spectra taken with ALFOSC at the Nordic Optical Telescope. The radial velocities display …
Gaussian Process Reconstruction of Reionization History
Hazra, Dhiraj Kumar; Krishak, Aditi
We reconstruct the history of reionization using Gaussian process regression. Using the UV luminosity data compilation from Hubble Frontiers Fields we reconstruct the redshift evolution of UV luminosity density and thereby the evolution of the source term in the ionization equation. This model-independent reconstruction rules out single power-law …
Broad He I 1.08-µm absorption from the obscurer in the active galaxy NGC 5548
Czerny, Bożena; Landt, Hermine; Kynoch, Daniel +2 more
The nucleus of the active galaxy NGC 5548 was the target of two intensive spectroscopic monitoring campaigns at X-ray, ultraviolet (UV), and optical frequencies in 2013/2014. These campaigns detected the presence of a massive obscuration event. In 2016/2017, Landt et al. conducted a near-IR spectroscopic monitoring campaign on NGC 5548 and discove…
The Venus Express observation of Venus' induced magnetosphere boundary at solar maximum
Zhang, T. L.; Wang, X.; Rong, Z. J. +9 more
The Venusian plasma environment is divided into two distinct regions by the induced magnetosphere boundary (IMB): the domain of solar wind protons and the domain of local planetary ions. Previous studies on the identification of the IMB gave various IMB definitions. Here we study the well-structured Venusian IMB with a sudden magnetic field rotati…
SiO Outflows as Tracers of Massive Star Formation in Infrared Dark Clouds
Caselli, Paola; Kong, Shuo; Tan, Jonathan C. +4 more
To study the early phases of massive star formation, we present ALMA observations of SiO(5-4) emission and VLA observations of 6 cm continuum emission toward 32 Infrared Dark Cloud clumps, spatially resolved down to ≲0.05 pc. Out of the 32 clumps, we detect SiO emission in 20 clumps, and in 11 of them the SiO emission is relatively strong and like…
SOFIA-upGREAT Imaging Spectroscopy of the [C II] 158 µm Fine-structure Line of the Sgr B Region in the Galactic Center
Harris, A. I.; Morris, M. R.; Stutzki, J. +8 more
We report SOFIA-upGREAT spectroscopic imaging of the [C II] 158 µm spectral line, as well as a number of [O I] 63 µm spectra, across a 67 × 45 pc field toward the Sgr B region in our Galactic center. The fully sampled and velocity-resolved [C II] images have 0.55 pc spatial and 1 km s-1 velocity resolutions. We find that Sgr…
The Second Earth Trojan 2020 XL5
Tholen, David J.; Hui, Man-To; Wiegert, Paul A. +1 more
The Earth Trojans are coorbitals librating around the Lagrange points L 4 or L 5 of the Sun-Earth system. Although many numerical studies suggest that they can maintain their dynamical status and be stable on timescales up to a few tens of thousands of years or even longer, they remain an elusive population. Thus far only one…