Search Publications
High-resolution Spectroscopic Abundances of Red Giant Branch Stars in NGC 6681
McWilliam, Andrew; Chaboyer, Brian; O'Malley, Erin M. +1 more
We obtain high-resolution spectra of nine red giant branch stars in NGC 6681 and perform the first detailed abundance analysis of stars in this cluster. We confirm cluster membership for these stars based on consistent radial velocities of 214.5 ± 3.7 km s-1 and find a mean [Fe/H] = -1.63 ± 0.07 dex and [α/Fe] = 0.42 ± 0.11 dex. Additio…
Further Constraints on Variations in the Initial Mass Function from Low-mass X-ray Binary Populations
Kundu, Arunav; Coulter, David A.; Zepf, Stephen E. +6 more
We present constraints on variations in the initial mass function (IMF) of nine local early-type galaxies based on their low-mass X-ray binary (LMXB) populations. Comprised of accreting black holes and neutron stars, these LMXBs can be used to constrain the important high-mass end of the IMF. We consider LMXB populations beyond the cores of the ga…
A Submillimeter Perspective on the Goods Fields. II. The High Radio Power Population in the Goods-N
Wang, W. -H.; Owen, F. N.; Barger, A. J. +2 more
We use ultradeep 20 cm data from the Karl G. Jansky Very Large Array and 850 µm data from SCUBA-2 and the Submillimeter Array of an 124 arcmin2 region of the Chandra Deep Field-north to analyze the high radio power ({P}20{cm}> {10}31 erg s-1 Hz-1) population. We find that 20 (42 ± 9%)…
Is There a CME Rate Floor? CME and Magnetic Flux Values for the Last Four Solar Cycle Minima
St. Cyr, O. C.; Webb, D. F.; Howard, R. A. +1 more
The recent prolonged activity minimum has led to the question of whether there is a base level of the solar magnetic field evolution that yields a “floor” in activity levels and also in the solar wind magnetic field strength. Recently, a flux transport model coupled with magneto-frictional simulations has been used to simulate the continuous magne…
Action-based Dynamical Modeling for the Milky Way Disk: The Influence of Spiral Arms
Bovy, Jo; Rix, Hans-Walter; Trick, Wilma H. +1 more
RoadMapping is a dynamical modeling machinery developed to constrain the Milky Way’s (MW) gravitational potential by simultaneously fitting an axisymmetric parametrized potential and an action-based orbit distribution function (DF) to discrete 6D phase-space measurements of stars in the Galactic disk. In this work, we demonstrate RoadMapping's rob…
ALMA CO Clouds and Young Star Complexes in the Interacting Galaxies IC 2163 and NGC 2207
Brinks, Elias; Struck, Curtis; Elmegreen, Bruce G. +5 more
Atacama Large Millimeter Array (ALMA) observations of CO(1-0) emission in the interacting galaxies IC 2163 and NGC 2207 are used to determine the properties of molecular clouds and their association with star-forming regions observed with the Hubble Space Telescope. Half of the CO mass is in 249 clouds, each more massive than 4.0× {10}5…
XMM-Newton and NuSTAR Simultaneous X-Ray Observations of IGR J11215-5952
Tiengo, A.; Sidoli, L.; Natalucci, L. +3 more
We report the results of an XMM-Newton and NuSTAR coordinated observation of the Supergiant Fast X-ray Transient (SFXT) IGR J11215-5952, performed on 2016 February 14, during the expected peak of its brief outburst, which repeats every ∼165 days. Timing and spectral analysis were performed simultaneously in the energy band 0.4-78 keV. A spin perio…
Molecular Gas Kinematics and Star Formation Properties of the Strongly-lensed Quasar Host Galaxy RXS J1131-1231
Riechers, Dominik A.; Pavesi, Riccardo; Leung, T. K. Daisy
We report observations of CO(J = 2 → 1) and {CO}(J=3\to 2) line emission toward the quadruply-lensed quasar RXS J1131-1231 at z = 0.654 obtained using the Plateau de Bure Interferometer (PdBI) and the Combined Array for Research in Millimeter-wave Astronomy (CARMA). Our lens modeling shows that the asymmetry in the double-horned CO(J = 2 → 1) line…
The 1.1 mm Continuum Survey of the Small Magellanic Cloud: Physical Properties and Evolution of the Dust-selected Clouds
Kohno, Kotaro; Yun, Min S.; Kawabe, Ryohei +18 more
The first 1.1 mm continuum survey toward the Small Magellanic Cloud (SMC) was performed using the AzTEC instrument installed on the ASTE 10 m telescope. This survey covered 4.5 deg2 of the SMC with 1σ noise levels of 5-12 mJy beam-1, and 44 extended objects were identified. The 1.1 mm extended emission has good spatial correl…
Are Complex Magnetic Field Structures Responsible for the Confined X-class Flares in Super Active Region 12192?
Li, Ting; Zhang, Jun; Chen, Huadong
From 2014 October 19 to 27, six X-class flares occurred in super active region (AR) 12192. They were all confined flares and were not followed by coronal mass ejections. To examine the structures of the four flares close to the solar disk center from October 22 to 26, we firstly employ composite triple-time images in each flare process to display …