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Morphologies of Two Massive Old Galaxies at z ~ 2.5
Stockton, Alan; Canalizo, Gabriela; Iye, Masanori +2 more
We present the results of NICMOS imaging of two massive galaxies photometrically selected to have old stellar populations at z ~ 2.5. Both galaxies are dominated by apparent disks of old stars, although one of them also has a small bulge comprising about one-third of the light at rest-frame 4800 Å. The presence of massive disks of old stars at hig…
Observations of Hα surges and ultraviolet jets above satellite sunspots
Jiang, Y. C.; Chen, H. D.; Ma, S. L.
Aims:To know more about the physical origin of surges and jets, we investigated seven successive surge events, which occurred above the satellite sunspots of active region NOAA 10720 on 2005 January 15.
Methods: Using data from the Transition Region and Coronal Explorer (TRACE), Big Bear Solar Observatory (BBSO) and Solar and Heliospheric Obse…
Cool and Hot Components of a Coronal Bright Point
He, Jiansen; Tian, Hui; Marsch, Eckart +1 more
We performed a systematic study of the Doppler shifts and electron densities measured in an EUV bright point (hereafter BP) observed in more than 10 EUV lines with formation temperatures from log (T/K) = 4.5 to 6.3. Those parts of a BP seen in transition region and coronal lines are defined as its cool and hot components, respectively. We find tha…
(42355) Typhon Echidna: Scheduling observations for binary orbit determination
Muinonen, K.; Spencer, J. R.; Grundy, W. M. +6 more
We describe a strategy for scheduling astrometric observations to minimize the number required to determine the mutual orbits of binary transneptunian systems. The method is illustrated by application to Hubble Space Telescope observations of (42355) Typhon-Echidna, revealing that Typhon and Echidna orbit one another with a period of 18.971±0.006 …
Analysis of plasma waves observed within local plasma injections seen in Saturn's magnetosphere
Gurnett, D. A.; Persoon, A. M.; Coates, A. J. +5 more
Plasma injections or density depletion regions have been reported to be a prolific feature of Saturn's inner magnetosphere. They are characterized by flux tubes of warm, tenuous plasma in a cooler, locally produced plasma background. The injected plasma undergoes dispersion in energy due to gradient and curvature drifts as the flux tube transports…
Prospects for the Detection of the Deep Solar Meridional Circulation
Birch, A. C.; Braun, D. C.
We perform helioseismic holography to assess the noise in p-mode travel-time shifts which would form the basis of inferences of large-scale flows throughout the solar convection zone. We also derive the expected travel times from a parameterized return (equatorward) flow component of the meridional circulation at the base of the convection zone fr…
Low/Hard State Spectra of GRO J1655-40 Observed with Suzaku
Dotani, Tadayasu; Yaqoob, Tahir; Yamaoka, Kazutaka +23 more
The Galactic black-hole binary GROJ1655-40, a source harboring superluminal jets, was observed with Suzaku on 2005 September 22-23. The source was detected over a broad and continuous energy range of 0.7-300keV, with an intensity of ∼50mCrab at 20keV. At a distance of 3.2kpc, the 0.7-300keV luminosity was ∼5.2 × 1036 ergs-1 (…
HST NICMOS Imaging of z ~ 2, 24 µm-selected Ultraluminous Infrared Galaxies
Helou, George; Colbert, James; Surace, Jason +3 more
We present Hubble Space Telescope NICMOS H-band imaging of 33 ultraluminous infrared galaxies (ULIRGs) at z ~ 2 that were selected from the 24 µm catalog of the Spitzer Extragalactic First Look Survey. The images reveal that at least 17 of the 33 objects are associated with interactions. Up to one-fifth of the sources in our sample could be …
The Globular Cluster Systems around NGC 3311 and NGC 3309
Whitmore, Bradley C.; Rothberg, Barry; Harris, William E. +2 more
We present extensive new photometry in (g', i') of the large globular cluster (GC) system around NGC 3311, the central cD galaxy in the Hydra cluster. Our GMOS data cover a 5.5' field of view and reach a limiting magnitude i' simeq 26.0, about 0.5 mag fainter than the turnover point of the GC luminosity function. We find that NGC 3311 has a huge p…
The nature of the hard state of Cygnus X-3
Larsson, S.; Zdziarski, A. A.; Vilhu, O. +4 more
The X-ray binary Cygnus X-3 (Cyg X-3) is a highly variable X-ray source that displays a wide range of observed spectral states. One of the main states is significantly harder than the others, peaking at ~20 keV, with only a weak low-energy component. Due to the enigmatic nature of this object, hidden inside the strong stellar wind of its Wolf-Raye…