Search Publications
Evidence for ponding and catastrophic floods in central Valles Marineris, Mars
Harrison, Keith P.; Chapman, Mary G.
The Valles Marineris canyon system of Mars is closely related to large flood channels, some of which emerge full born from chaotic terrain in canyon floors. Coprates Chasma, one of the largest Valles Marineris canyons, is connected at its west end to Melas Chasma and on its east end to chaotic terrain-filled Capri and Eos Chasmata. The area from c…
The Birth Place of the Type Ic Supernova 2007gr
Stephens, Andrew W.; Smartt, Stephen J.; Mattila, Seppo +8 more
We report our attempts to locate the progenitor of the peculiar Type Ic SN 2007gr in Hubble Space Telescope (HST) preexplosion images of the host galaxy, NGC 1058. Aligning adaptive optics Altair/NIRI imaging of SN 2007gr from the Gemini (North) Telescope with the preexplosion HST WFPC2 images, we identify the supernova (SN) position on the HST fr…
Supernovae in Low-Redshift Galaxy Clusters: Observations by the Wise Observatory Optical Transient Search (WOOTS)
Filippenko, Alexei V.; Maoz, Dan; Gal-Yam, Avishay +1 more
We describe the Wise Observatory Optical Transient Search (WOOTS), a survey for supernovae (SNe) and other variable and transient objects in the fields of redshift 0.06-0.2 Abell galaxy clusters. We present the survey design and data analysis procedures, and our object detection and follow-up strategies. We have obtained follow-up spectroscopy for…
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 (…