Search Publications
A Dwarf Nova in the Globular Cluster M13
Knigge, C.; van den Berg, M.; Servillat, M. +4 more
Dwarf novae (DNe) in globular clusters (GCs) seem to be rare with only 13 detections in the 157 known Galactic GCs. We report the identification of a new DN in M13, the 14th DN identified in a GC to date. Using the 2 m Faulkes Telescope North, we conducted a search for stars in M13 that show variability over a year (2005-2006) on timescales of day…
The M81 Group Dwarf Irregular Galaxy DDO 165. II. Connecting Recent Star Formation with Interstellar Medium Structures and Kinematics
Cannon, John M.; Dolphin, Andrew E.; Skillman, Evan D. +8 more
We compare the stellar populations and complex neutral gas dynamics of the M81 group dIrr galaxy DDO 165 using data from the Hubble Space Telescope and the Very Large Array. Cannon et al. in Paper I of this series identified two kinematically distinct H I components, multiple localized high velocity gas features, and eight H I holes and shells (th…
The X-Ray Counterpart of the High-B Pulsar PSR J0726-2612
van Kerkwijk, M. H.; Speagle, J. S.; Kaplan, D. L.
Middle-aged, cooling neutron stars are observed both as relatively rapidly spinning radio pulsars and as more slowly spinning, strongly magnetized isolated neutron stars (INSs), which stand out by their thermal X-ray spectra. The difference between the two classes may be that the INSs initially had much stronger magnetic fields, which decayed. To …
Herschel Observations of the T Cha Transition Disk: Constraining the Outer Disk Properties
Henning, Thomas; Pinte, Christophe; Cieza, Lucas A. +7 more
T Cha is a nearby (d ~ 100 pc) transition disk known to have an optically thin gap separating optically thick inner and outer disk components. Huélamo et al. recently reported the presence of a low-mass object candidate within the gap of the T Cha disk, giving credence to the suspected planetary origin of this gap. Here we present the Herschel pho…
Detection of Brown Dwarf Like Objects in the Core of NGC 3603
McCarthy, Patrick J.; Calzetti, Daniela; Whitmore, Bradley C. +23 more
We used near-infrared data obtained with the Wide Field Camera 3 on the Hubble Space Telescope to identify objects having the colors of brown dwarfs (BDs) in the field of the massive galactic cluster NGC 3603. These are identified through a combination of narrow- and medium-band filters which span the J and H bands and are particularly sensitive t…
Uncovering the Wave Nature of the EIT Wave for the 2010 January 17 Event through Its Correlation to the Background Magnetosonic Speed
Wu, S. T.; Feng, X. S.; Jiang, C. W. +3 more
An EIT wave, which typically appears as a diffuse brightening that propagates across the solar disk, is one of the major discoveries of the Extreme ultraviolet Imaging Telescope on board the Solar and Heliospheric Observatory. However, the physical nature of the so-called EIT wave continues to be debated. In order to understand the relationship be…
Far-ultraviolet Number Counts of Field Galaxies
Gardner, Jonathan P.; Teplitz, Harry I.; de Mello, Duilia F. +2 more
The far-ultraviolet (FUV) number counts of galaxies constrain the evolution of the star formation rate density of the universe. We report the FUV number counts computed from FUV imaging of several fields including the Hubble Ultra Deep Field, the Hubble Deep Field North, and small areas within the GOODS-North and South fields. These data were obta…
Evolution of Spinning and Braiding Helicity Fluxes in Solar Active Region NOAA 10930
Ravindra, B.; Yoshimura, Keiji; Dasso, Sergio
The line-of-sight magnetograms from Solar Optical Telescope Narrowband Filter Imager observations of NOAA Active Region 10930 have been used to study the evolution of spinning and braiding helicities over a period of five days starting from 2006 December 9. The north (N) polarity sunspot was the follower and the south (S) polarity sunspot was the …
Ultra-compact Dwarfs in the Fossil Group NGC 1132
Madrid, Juan P.
Eleven ultra-compact dwarf (UCD) and 39 extended star cluster candidates are found to be associated with the galaxy NGC 1132. This giant elliptical galaxy is the remnant of a fossil group. UCD and extended star cluster candidates are identified through the analysis of their structural parameters, colors, spatial distribution, and luminosity using …
Unveiling the Nature of IGR J17177-3656 with X-Ray, Near-infrared, and Radio Observations
Nowak, M. A.; Chaty, S.; Rodriguez, J. +6 more
We report on the first broadband (1-200 keV) simultaneous Chandra-INTEGRAL observations of the recently discovered hard X-ray transient IGR J17177-3656 that took place on 2011 March 22, about two weeks after the source discovery. The source had an average absorbed 1-200 keV flux of about 8 × 10-10 erg cm-2 s-1. We …