Search Publications
The Unimodal Distribution of Blue Straggler Stars in M75 (NGC 6864)
Dalessandro, E.; Contreras Ramos, R.; Ferraro, F. R. +2 more
We have used a combination of multiband high-resolution and wide-field ground-based observations to image the Galactic globular cluster M75 (NGC 6864). The extensive photometric sample covers the entire cluster extension, from the very central regions out to the tidal radius, allowing us to determine the center of gravity and to construct the most…
Herschel Search for O2 toward the Orion Bar
Li, Di; van Dishoeck, Ewine F.; Encrenaz, Pierre +15 more
We report the results of a search for molecular oxygen (O2) toward the Orion Bar, a prominent photodissociation region at the southern edge of the H II region created by the luminous Trapezium stars. We observed the spectral region around the frequency of the O2 NJ = 33-12 transition at 487 GH…
XMM-Newton View of Swift J1834.9-0846 and Its Magnetar Wind Nebula
Kouveliotou, C.; Pavlov, G. G.; Göǧüş, E. +3 more
We report on the analysis of two XMM-Newton observations of the recently discovered soft gamma repeater Swift J1834.9-0846, taken in 2005 September and one month after the source went into outburst on 2011 August 7. We performed timing and spectral analyses on the point source as well as on the extended emission. We find that the source period is …
Exploring the Diversity of Groups at 0.1 < z < 0.8 with X-Ray and Optically Selected Samples
Mulchaey, John S.; Connelly, J. L.; Balogh, Michael L. +8 more
We present the global group properties of two samples of galaxy groups containing 39 high-quality X-ray-selected systems and 38 optically (spectroscopically) selected systems in coincident spatial regions at 0.12 < z < 0.79. The total mass range of the combined sample is ~(1012-5) × 1014 M ⊙. Only nine optica…
Identification of Ambient Molecular Clouds Associated with Galactic Supernova Remnant IC 443
Yun, Min S.; Koo, Bon-Chul; Lee, Jae-Joon +3 more
The Galactic supernova remnant (SNR) IC 443 is one of the most studied core-collapse SNRs for its interaction with molecular clouds. However, the ambient molecular clouds with which IC 443 is interacting have not been thoroughly studied and remain poorly understood. Using the Five College Radio Astronomy Observatory 14 m telescope, we obtained ful…
The Occurrence and Speed of CMEs Related to Two Characteristic Evolution Patterns of Helicity Injection in Their Solar Source Regions
Wang, Haimin; Chae, Jongchul; Liu, Rui +4 more
Long-term (a few days) variation of magnetic helicity injection was calculated for 28 solar active regions that produced 47 coronal mass ejections (CMEs) to find its relationship to the CME occurrence and speed using SOHO/MDI line-of-sight magnetograms. As a result, we found that the 47 CMEs can be categorized into two different groups by two char…
A Herschel Search for Cold Dust in Brown Dwarf Disks: First Results
Pascucci, Ilaria; Henning, Thomas; Ménard, François +7 more
We report initial results from a Herschel program to search for far-infrared emission from cold dust around a statistically significant sample of young brown dwarfs. The first three objects in our survey are all detected at 70 µm, and we report the first detection of a brown dwarf at 160 µm. The flux densities are consistent with the p…
Detecting the Warm-Hot Intergalactic Medium through X-Ray Absorption Lines
Shull, J. Michael; Wang, Q. Daniel; Yao, Yangsen +1 more
The warm-hot intergalactic medium (WHIM) at temperatures 105-107 K is believed to contain 30%-50% of the baryons in the local universe. However, all current X-ray detections of the WHIM at redshifts z > 0 are of low statistical significance (lsim 3σ) and/or controversial. In this work, we aim to establish the detection lim…
Far-ultraviolet Continuum Emission: Applying This Diagnostic to the Chromospheres of Solar-mass Stars
France, Kevin; Linsky, Jeffrey L.; Ayres, Tom +2 more
The far-ultraviolet (FUV) continuum flux is recognized as a very sensitive diagnostic of the temperature structure of the Sun's lower chromosphere. Until now analysis of the available stellar FUV data has shown that solar-type stars must also have chromospheres, but quantitative analyses of stellar FUV continua require far higher quality spectra a…
Investigation of Intermittency in Magnetohydrodynamics and Solar Wind Turbulence: Scale-dependent Kurtosis
Oughton, Sean; Matthaeus, William H.; Wan, Minping +1 more
The behavior of scale-dependent (or filtered) kurtosis is studied in the solar wind using magnetic field measurements from the ACE and Cluster spacecraft at 1 AU. It is also analyzed numerically with high-resolution magnetohydrodynamic spectral simulations. In each case the filtered kurtosis increases with wavenumber, implying the presence of cohe…