Search Publications
Spectroscopic Confirmation of Faint Lyman Break Galaxies Near Redshift Five in the Hubble Ultra Deep Field
Dickinson, Mark; Hathi, Nimish; Cohen, Seth +17 more
We present the faintest spectroscopically confirmed sample of z ~ 5 Lyman break galaxies (LBGs) to date. The sample is based on slitless grism spectra of the Hubble Ultra Deep Field region from the Grism ACS Program for Extragalactic Science (GRAPES) and Probing Evolution and Reionization Spectroscopically (PEARS) projects, using the G800L grism o…
An Ultracompact X-Ray Binary in the Globular Cluster NGC 1851
Maccarone, T. J.; Knigge, C.; Long, K. S. +2 more
We present far-ultraviolet photometry obtained with the Hubble Space Telescope of the low-mass X-ray binary 4U 0513-40 in the globular cluster NGC 1851. Our observations reveal a clear, roughly sinusoidal periodic signal with P sime 17 minutes and amplitude 3%-10%. The signal appears fully coherent and can be modeled as a simple reprocessing effec…
Solar Coronal Structure and Stray Light in TRACE
DeForest, C. E.; Wills-Davey, M. J.; Martens, P. C. H.
Using the 2004 Venus transit of the Sun to constrain a semiempirical point-spread function (PSF) for the TRACE EUV solar telescope, we have measured the effect of stray light in that telescope. We find that 43% of 171 Å EUV light that enters TRACE is scattered, either through diffraction off the entrance filter grid or through other nonspecular ef…
Large-Scale Flows in Prominence Cavities
Brooks, D. H.; Reeves, K. K.; Gibson, S. E. +5 more
Regions of rarefied density often form cavities above quiescent prominences. We observed two different cavities with the Coronal Multichannel Polarimeter on 2005 April 21 and with Hinode/EIS on 2008 November 8. Inside both of these cavities, we find coherent velocity structures based on spectral Doppler shifts. These flows have speeds of 5-10 km s…
Chandra Observations of the cl1604 Supercluster at z = 0.9: Evidence for an Overdensity of Active Galactic Nuclei
Kocevski, Dale D.; Fassnacht, Christopher D.; Lubin, Lori M. +3 more
We present the results of Chandra observations of the Cl1604 supercluster at z ~ 0.9. The system is the largest structure mapped at redshifts approaching unity, containing at least eight spectroscopically confirmed galaxy clusters and groups. Using two 50 ks ACIS-I pointings we examine both the X-ray point-source population and the diffuse emissio…
Extended X-Ray Emission in Radio Galaxies: The Peculiar Case of 3C 305
Macchetto, F. D.; Capetti, A.; Gilli, R. +8 more
Extended X-ray structures are common in active galactic nuclei. Here, we present the first case of a compact steep spectrum radio galaxy, 3C 305, in which the X-ray radiation appears to be associated with the optical emission line region, dominated by the [O III]5007. On the basis of a morphological study performed using a comparison between the X…
The Clustering Behavior of Pre-Main-Sequence Stars in NGC 346 in the Small Magellanic Cloud
Gouliermis, Dimitrios A.; Klessen, Ralf S.; Schmeja, Stefan
We present evidence that the star-forming region NGC 346/N66 in the Small Magellanic Cloud is the product of hierarchical star formation, probably from more than one star formation event. We investigate the spatial distribution and clustering behavior of the pre-main-sequence (PMS) stellar population in the region, using data obtained with Hubble …
Robust Determination of the Major Merger Fraction at z = 0.6 in the Groth Strip
Eliche-Moral, M. Carmen; Balcells, Marc; Guzmán, Rafael +6 more
We measure the fraction of galaxies undergoing disk-disk major mergers (f mph m ) at intermediate redshifts (0.35 <= z < 0.85) by studying the asymmetry index A of galaxy images. Results are provided for B- and K s-band absolute magnitude selected samples from the Groth strip in the galaxy origins and young …
2MASS 22344161+4041387AB: A Wide, Young, Accreting, Low-Mass Binary in the LkHα233 Group
Shkolnik, Evgenya; Cushing, Michael C.; Dupuy, Trent J. +6 more
We report the discovery of a young, 0farcs16 binary, 2M2234+4041AB, found as the result of a Keck laser guide star adaptive optics imaging survey of young field ultracool dwarfs. Spatially resolved near-infrared photometry and spectroscopy indicate that the luminosity and temperature ratios of the system are near unity. From optical and near-infra…
Local Twist and Current Helicity Distributions of Active Region NOAA 10930
Liu, Yu; Su, J. T.; Suematsu, Y. +2 more
Hinode high-quality vector magnetograms and G-band data are utilized to study the distributions of local twist α z and current helicity hc on the active region of NOAA 10930. The new findings are as follows. (1) The patches of positive and negative helicities were intermixed showing a mesh pattern in the umbra and a thread p…