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Even Simpler Modeling of Quadruply Lensed Quasars (and Random Quartets) Using Witt's Hyperbola
Schechter, Paul L.; Wynne, Raymond A.
Witt (1996) has shown that, for an elliptical potential, the four images of a quadruply lensed quasar lie on a rectangular hyperbola that passes through the unlensed quasar position and the center of the potential as well. Wynne & Schechter (2018) have shown that, for the singular isothermal elliptical potential (SIEP), the four images also li…
Observations of the Ultraviolet-bright Star Barnard 29 in the Globular Cluster M13 (NGC 6205)
Chayer, Pierre; Reid, I. N.; Dixon, William V. +1 more
We have analyzed spectra from FUSE, COS, GHRS, and Keck HIRES of the UV-bright star Barnard 29 in M13 (NGC 6205). By comparing the photospheric abundances derived from multiple ionization states of C, N, O, Si, and S, we infer an effective temperature {T}eff} = 21,400 ± 400 K. Balmer-line fits yield a surface gravity {log}g = 3.10 ± 0.0…
FIFI-LS Observations of the Circumnuclear Ring— Probing the High-density Phase of the PDR
Poglitsch, A.; Looney, L. W.; Krabbe, A. +13 more
We investigate the nature of dense gas in the 3-10 pc circumnuclear ring (CNR) in the galactic center of the Milky Way, which is a structure that may be dynamically connecting the supermassive black hole Sgr A* with the central molecular zone at the 100 pc scale, and is the closest reservoir of molecular gas to the massive stars located within the…
Measuring the Absolute Total Intrinsic Redshifts (Surface Gravity Plus the Convective Blueshift) of the Main-sequence Stars and Red Giants using Gaia Data
Dai, De-Chang; Stojkovic, Dejan; Li, ZhiGang
We analyze the GAIA release II data to demonstrate how one can measure the absolute total intrinsic redshifts of the main-sequence stars and red giants. We remove the relative velocity components of the stars’ motion with respect to the Sun by doing the analysis in the local standard of the rest frame defined by the average stars’ motion. We provi…
High Confidence Optical Confirmations among the High Signal-to-noise Planck Cluster Candidates
Infante, L.; Hughes, John P.; Doze, Peter +3 more
We report on newly identified galaxy clusters from the high signal-to-noise (>5σ) end of the second all-sky Planck Sunyaev-Zel’dovich (SZ) catalog (PSZ2). The clusters are identified in deep, optical imaging from the Kitt Peak National Observatory 4 m Mayall telescope taken between 2014 and 2017. Here we focus on the highest richness systems, a…
Ionization Mechanisms in Quasar Outflows
Veilleux, Sylvain; Rupke, David S. N.; Hinkle, Jason T.
The various ionization mechanisms at play in active galactic nuclei (AGN) and quasars have been well studied, but relatively little has been done to separately investigate the contributions of these ionization mechanisms within the host galaxy and outflowing components. Using Gemini integral field spectroscopy data, we study the ionization propert…
Dynamical masses and mass-to-light ratios of resolved massive star clusters - I. NGC 419 and NGC 1846
Mateo, Mario; Mackey, A. D.; Roederer, Ian U. +4 more
As an introduction of a kinematic survey of Magellanic Cloud (MC) star clusters, we report on the dynamical masses and mass-to-light ratios (M/L) of NGC 419 (Small Magellanic Cloud) and NGC 1846 (Large Magellanic Cloud). We have obtained more than one hundred high-resolution stellar spectra in and around each cluster using the multi-object spectro…
Resonant assisted annihilation
Nath Maity, Tarak; Sankar Ray, Tirtha
Assisted annihilation is a novel mechanism to generate viable sub-GeV thermal dark matter, where a pair of stable dark matter annihilates with an assister to Standard Model states. Typically such 3 → 2 annihilation topologies are flux suppressed compared to 2 → 2 processes. In this paper, we explore the possibility of a resonant 3 → 2 assisted ann…
Exposure Experiments of Amorphous Silicates and Organics to Cometary Ice and Vapor Analogs
Takigawa, Aki; Kimura, Yuki; Davidsson, Björn +2 more
Hydration is a major mineral alteration process in primitive asteroids and it might occur in comet nuclei; however, it is poorly understood at low temperatures, especially below the freezing point of water. Long-duration experiments were performed with exposures of amorphous silicate nanoparticles and organic compounds (glycine and ribose) to D
Liquid Water Detection under the South Polar Layered Deposits of Mars—a Probabilistic Inversion Approach
Lauro; Soldovieri; Orosei +7 more