Search Publications
In Situ Observations of a Secondary Magnetic Island in an Ion Diffusion Region and Associated Energetic Electrons
Wang, Shui; Lu, Quanming; Wang, Rongsheng +1 more
Numerical simulations have predicted that an extended current sheet may be unstable to secondary magnetic islands in the vicinity of the X line, and these islands can dramatically influence the reconnection rate. In this Letter, we present the first evidence of such a secondary island near the center of an ion diffusion region, which is consistent…
Evidence for Hesperian impact-induced hydrothermalism on Mars
Tornabene, Livio L.; Roush, Ted L.; Bishop, Janice L. +7 more
Several hydrated silicate deposits on Mars are observed within craters and are interpreted as excavated Noachian material. Toro crater (71.8°E, 17.0°N), located on the northern edge of the Syrtis Major Volcanic Plains, shows spectral and morphologic evidence of impact-induced hydrothermal activity. Spectroscopic observations were used to identify …
A recent disruption of the main-belt asteroid P/2010A2
Mutchler, Max; Jewitt, David; Agarwal, Jessica +2 more
Most inner main-belt asteroids are primitive rock and metal bodies in orbit about the Sun between Mars and Jupiter. Disruption, through high-velocity collisions or rotational spin-up, is believed to be the primary mechanism for the production and destruction of small asteroids and a contributor to dust in the Sun's zodiacal cloud, while analogous …
The Collimation and Energetics of the Brightest Swift Gamma-ray Bursts
Butler, N. R.; Cenko, S. B.; Price, P. A. +23 more
Long-duration gamma-ray bursts (GRBs) are widely believed to be highly collimated explosions (bipolar conical outflows with half-opening angle θ≈ 1°-10°). As a result of this beaming factor, the true energy release from a GRB is usually several orders of magnitude smaller than the observed isotropic value. Measuring this opening angle, typically i…
The Extended Chandra Deep Field-South Survey: Optical Spectroscopy of Faint X-ray Sources with the VLT and Keck
Finoguenov, A.; Lehmer, B. D.; Alexander, D. M. +26 more
We present the results of a program to acquire high-quality optical spectra of X-ray sources detected in the Extended-Chandra Deep Field-South (E-CDF-S) and its central 2 Ms area. New spectroscopic redshifts, up to z = 4, are measured for 283 counterparts to Chandra sources with deep exposures (t ~ 2-9 hr per pointing) using multi-slit facilities …
The WFC3 Infrared Spectroscopic Parallel (WISP) Survey
Scarlata, C.; Shim, H.; Malkan, M. +12 more
We present the WFC3 Infrared Spectroscopic Parallel (WISP) Survey. WISP is obtaining slitless, near-infrared grism spectroscopy of ~90 independent, high-latitude fields by observing in the pure-parallel mode with the Wide Field Camera Three on the Hubble Space Telescope for a total of ~250 orbits. Spectra are obtained with the G 102 (λ …
Gas, dust and stars in the SCUBA galaxy, SMMJ02399-0136: the EVLA reveals a colossal galactic nursery
Kneib, J. -P.; Ivison, R. J.; Smail, Ian +5 more
We present new multiwavelength observations of the first submillimetre-selected galaxy (SMG) SMMJ02399-0136 at z = 2.8. These observations include mapping of the CO J=1->0 emission using elements of the Expanded Very Large Array, as well as high-resolution 1.4-GHz imaging and optical/infrared (IR) data from the Very Large Array, Hubble Space Te…
A cold and wet Mars
Fairén, Alberto G.
Water on Mars has been explained by invoking controversial and mutually exclusive solutions based on warming the atmosphere with greenhouse gases (the "warm and wet" Mars) or on local thermal energy sources acting in a global freezing climate (the "cold and dry" Mars). Both have critical limitations and none has been definitively accepted as a com…
On the 3-D reconstruction of Coronal Mass Ejections using coronagraph data
St. Cyr, O. C.; Mierla, M.; Zhukov, A. N. +26 more
Coronal Mass ejections (CMEs) are enormous eruptions of magnetized plasma expelled from the Sun into the interplanetary space, over the course of hours to days. They can create major disturbances in the interplanetary medium and trigger severe magnetic storms when they collide with the Earth's magnetosphere. It is important to know their real spee…
A Hubble Space Telescope NICMOS and ACS morphological study of z ~ 2 submillimetre galaxies
Ivison, R. J.; Smail, Ian; Alexander, D. M. +6 more
We present a quantitative morphological analysis using Hubble Space Telescope Near Infrared Camera and Multi-Object Spectrometer H160-band imaging and Advanced Camera for Surveys I775-band imaging of 25 spectroscopically confirmed submillimetre galaxies (SMGs) which have redshifts between (). Our analysis also employs a compa…