Search Publications
Characteristics of Solar Energetic Ions as a Function of Longitude
Cohen, C. M. S.; Mewaldt, R. A.; Mason, G. M.
Since the 2006 launch of STEREO, multi-spacecraft studies have yielded several surprising results regarding the spread of solar energetic particles (SEPs) within the inner heliosphere. We have investigated the role of energy and ridigity, using ACE and STEREO 10 MeV n-1 oxygen data to identify 41 large SEP events observed by two or thre…
CO-driven Activity in Comet C/2017 K2 (PANSTARRS)
Chambers, Kenneth C.; Magnier, Eugene; Bauer, James +12 more
Comet C/2017 K2 (PANSTARRS) was discovered by the Pan-STARRS1 (PS1) Survey on 2017 May 21 at a distance of 16.09 au from the Sun, the second most distant discovery of an active comet. Pre-discovery images in the PS1 archive back to 2014 and additional deep CFHT images between 2013 May 10-13 showed the comet to be active at 23.75 au. We derive an u…
Discovery of Extended Main-sequence Turnoffs in Four Young Massive Clusters in the Magellanic Clouds
Milone, Antonino P.; Deng, Licai; de Grijs, Richard +1 more
An increasing number of young massive clusters (YMCs) in the Magellanic Clouds have been found to exhibit bimodal or extended main sequences (MSs) in their color-magnitude diagrams (CMDs). These features are usually interpreted in terms of a coeval stellar population with different stellar rotational rates, where the blue and red MS stars are popu…
What Causes the High Apparent Speeds in Chromospheric and Transition Region Spicules on the Sun?
Martínez-Sykora, Juan; De Pontieu, Bart; Chintzoglou, Georgios
Spicules are the most ubuiquitous type of jets in the solar atmosphere. The advent of high-resolution imaging and spectroscopy from the Interface Region Imaging Spectrograph (IRIS) and ground-based observatories has revealed the presence of very high apparent motions of order 100-300 km s-1 in spicules, as measured in the plane of the s…
Identification of Young Stellar Variables with KELT for K2. I. Taurus Dippers and Rotators
Cargile, Phillip A.; Pepper, Joshua; Stassun, Keivan G. +13 more
One of the most well-studied young stellar associations, Taurus-Auriga, was observed by the extended Kepler mission, K2, in the spring of 2017. K2 Campaign 13 (C13) is a unique opportunity to study many stars in this young association at high photometric precision and cadence. Using observations from the Kilodegree Extremely Little Telescope (KELT…
Evolutionary Phases of Gas-rich Galaxies in a Galaxy Cluster at z = 1.46
Tamura, Yoichi; Kohno, Kotaro; Suzuki, Tomoko L. +7 more
We report a survey of molecular gas in galaxies in the XMMXCS J2215.9-1738 cluster at z = 1.46. We have detected emission lines from 17 galaxies within a radius of R 200 from the cluster center, in Band 3 data of the Atacama Large Millimeter/submillimeter Array, with a coverage of 93-95 GHz in frequency and 2.33 arcmin2 in sp…
Statistical Detection of the He II Transverse Proximity Effect: Evidence for Sustained Quasar Activity for >25 Million Years
Hennawi, Joseph F.; Prochaska, J. Xavier; Crighton, Neil H. M. +2 more
The He II transverse proximity effect—enhanced He II {Ly}α transmission in a background sightline caused by the ionizing radiation of a foreground quasar—offers a unique opportunity to probe the morphology of quasar-driven He II reionization. We conduct a comprehensive spectroscopic survey to find z∼ 3 quasars in the foreground of 22 background qu…
Quiescent Prominence Dynamics Observed with the Hinode Solar Optical Telescope. II. Prominence Bubble Boundary Layer Characteristics and the Onset of a Coupled Kelvin-Helmholtz Rayleigh-Taylor Instability
Liu, Wei; Hillier, Andrew; Berger, Thomas
We analyze solar quiescent prominence bubble characteristics and instability dynamics using Hinode/Solar Optical Telescope data. We measure the bubble expansion rate, prominence downflows, and the profile of the boundary layer brightness and thickness as a function of time. The largest bubble analyzed rises into the prominence with a speed of abou…
Mrk 71/NGC 2366: The Nearest Green Pea Analog
Jaskot, Anne E.; James, Bethan L.; Oey, M. S. +1 more
We present the remarkable discovery that the dwarf irregular galaxy NGC 2366 is an excellent analog of the Green Pea (GP) galaxies, which are characterized by extremely high ionization parameters. The similarities are driven predominantly by the giant H II region Markarian 71 (Mrk 71). We compare the system with GPs in terms of morphology, excitat…
The MOSDEF Survey: The Prevalence and Properties of Galaxy-wide AGN-driven Outflows at z ∼ 2
Siana, Brian; Azadi, Mojegan; Aird, James +10 more
Using observations from the first 2 yr of the MOSFIRE Deep Evolution Field (MOSDEF) survey, we study 13 active galactic nucleus (AGN) driven outflows detected from a sample of 67 X-ray, IR, and/or optically selected AGNs at z∼ 2. The AGNs have bolometric luminosities of ∼ {10}44{--}{10}46 {erg} {{{s}}}-1, including…