Search Publications
Discovery of Tidal Tails around the Old Open Cluster NGC 2506
Gao, Xinhua
We report the discovery of tidal tails around the old open cluster NGC 2506 based on Gaia-DR2. A principal-component analysis and Gaussian mixture model are used to identify extra-tidal stars. We identify 2301 stars closely related to the cluster, 147 of which are likely extra-tidal stars. We find clear evidence for the existence of two well-defin…
Eclipsing Binaries in the Open Cluster Ruprecht 147. III. The Triple System EPIC 219552514 at the Main-sequence Turnoff
Torres, Guillermo; Vanderburg, Andrew; Rizzuto, Aaron C. +3 more
Spectroscopic observations are reported for the 2.75 day, double-lined, detached eclipsing binary EPIC 219552514 located at the turnoff of the old nearby open cluster Ruprecht 147. A joint analysis of our radial-velocity measurements and the K2 light curve leads to masses of ${M}_{1}={1.509}_{-0.056}^{+0.063}\,{M}_{\odot }$ and ${M}_{2}={0.649}_{-…
OGLE-ing the Magellanic System: Cepheids in the Bridge
Udalski, Andrzej; Mróz, Przemek; Szymański, Michał K. +12 more
We present a detailed analysis of the Magellanic Bridge Cepheid sample constructed using the Optical Gravitational Lensing Experiment Collection of Variable Stars. Our updated Bridge sample contains 10 classical and 13 anomalous Cepheids. We calculate their individual distances using optical period-Wesenheit relations and construct three-dimension…
Measuring the Heating and Cooling of the Interstellar Medium at High Redshift: PAH and [C II] Observations of the Same Star-forming Galaxies at z ∼ 2
Kirkpatrick, Allison; Dickinson, Mark E.; McKinney, Jed +4 more
Star formation depends critically on cooling mechanisms in the interstellar medium (ISM); however, thermal properties of gas in galaxies at the peak epoch of star formation (z ∼ 2) remain poorly understood. A limiting factor in understanding the multiphase ISM is the lack of multiple tracers detected in the same galaxies, such as Polycyclic Aromat…
On the Absence of High-redshift AGNs: Little Growth in the Supermassive Black Hole Population at High Redshifts
Bauer, F. E.; Barger, A. J.; Cowie, L. L. +1 more
We search for high-redshift (z > 4.5) X-ray active galactic nuclei (AGNs) in the deep central (off-axis angle < 5'7) region of the 7 Ms Chandra Deep Field-South X-ray image. We compile an initial candidate sample from direct X-ray detections. We then probe more deeply in the X-ray data by using preselected samples with high spatial resolutio…
A Magnetic White Dwarf Accretion Model for the Anomalous X-Ray Pulsar 4U 0142+61
Rodrigues, Claudia V.; Coelho, Jaziel G.; Castro, Manuel +2 more
The quiescent emission of the anomalous X-ray pulsar (AXP) 4U 0142+61 extends over a broad range of energy, from radio up to hard X-rays. In particular, this object is unique among soft gamma-ray repeaters (SGRs) and AXPs in presenting simultaneously mid-infrared emission and pulsed optical emission. In spite of the many propositions to explain th…
The Demagnetization of the Venusian Ionosphere under Nearly Flow-aligned Interplanetary Magnetic Fields
Xu, Qi; Zhang, Tielong; Xu, Xiaojun +4 more
Previous studies suggested that the interplanetary magnetic field (IMF) has a significant influence on the Venusian-induced magnetosphere. We present observations by Venus Express under a nearly flow-aligned IMF condition to investigate the demagnetization of the Venusian ionosphere. Our results show that the magnetic barrier becomes weak and narr…
Optical Transmission Spectra of Hot Jupiters: Effects of Scattering
Tinetti, Giovanna; Sengupta, Sujan; Chakrabarty, Aritra
We present new grids of transmission spectra for hot Jupiters by solving the multiple-scattering radiative transfer equations with non-zero scattering albedo instead of using the Beer-Bouguer-Lambert law for the change in the transmitted stellar intensity. The diffused reflection and transmission due to scattering increase the transmitted stellar …
A Photoionized Accretion Disk around a Young High-mass Star
Sanhueza, Patricio; Garay, Guido; Guzmán, Andrés E. +2 more
We present high spatial resolution (52 au) observations of the high-mass young stellar object (HMYSO) G345.4938+01.4677 made using the Atacama Large Millimeter/submillimeter Array. This O-type HMYSO is located at 2.38 kpc and is associated with a luminosity of 1.5 × 105 L⊙. We detect circumstellar emission from the H38β hydro…
Using the "Ghost Front" to Predict the Arrival Time and Speed of CMEs at Venus and Earth
Wang, Yuming; Shen, Chenglong; Lockwood, Mike +7 more
Using in situ measurements and remote-sensing observations, we study two coronal mass ejections (CMEs) that left the Sun on 2012 June 13-14 and impacted both Venus and Earth while the planets were in close radial alignment. The two CMEs generate multiple fronts in Solar Terrestrial Relations Observatory (STEREO)/Heliospheric Imager (HI) images, wh…