Search Publications
Discovery of a Very Bright Strongly Lensed Galaxy Candidate at z ≈ 7.6
Ford, H. C.; Frye, B. L.; Infante, L. +11 more
Using Hubble Space Telescope (HST) and Spitzer IRAC imaging, we report the discovery of a very bright strongly lensed Lyman break galaxy (LBG) candidate at z ~ 7.6 in the field of the massive galaxy cluster Abell 1689 (z = 0.18). The galaxy candidate, which we refer to as A1689-zD1, shows a strong z850 - J110 break of at leas…
Transient horizontal magnetic fields in solar plage regions
Lites, B. W.; Ichimoto, K.; Ishikawa, R. +9 more
Aims:We report the discovery of isolated, small-scale emerging magnetic fields in a plage region with the Solar Optical Telescope aboard Hinode.
Methods: Spectro-polarimetric observations were carried out with a cadence of 34 s for the plage region located near disc center. The vector magnetic fields are inferred by Milne-Eddington inversion. …
Statistical validation of a solar wind propagation model from 1 to 10 AU
Hansen, Kenneth C.; Zieger, Bertalan
A one-dimensional (1-D) numerical magnetohydrodynamic (MHD) code is applied to propagate the solar wind from 1 AU through 10 AU, i.e., beyond the heliocentric distance of Saturn's orbit, in a non-rotating frame of reference. The time-varying boundary conditions at 1 AU are obtained from hourly solar wind data observed near the Earth. Although simi…
A Massive Neutron Star in the Globular Cluster M5
Freire, Paulo C. C.; Hessels, Jason W. T.; van den Berg, Maureen +1 more
We report the results of 19 years of Arecibo timing for two pulsars in the globular cluster NGC 5904 (M5), PSR B1516+02A (M5A) and PSR B1516+02B (M5B). This has resulted in the measurement of the proper motions of these pulsars and, by extension, that of the cluster itself. M5B is a 7.95 ms pulsar in a binary system with a >0.13 M⊙ c…
Precise Measurement of the Spin Parameter of the Stellar-Mass Black Hole M33 X-7
McClintock, Jeffrey E.; Liu, Jifeng; Davis, Shane W. +2 more
In prior work, Chandra and Gemini-North observations of the eclipsing X-ray binary M33 X-7 have yielded measurements of the mass of its black hole primary and the system's orbital inclination angle of unprecedented accuracy. Likewise, the distance to the binary is known to a few percent. In an analysis based on these precise results, 15 Chandra an…
Saturn kilometric radiation: Average and statistical properties
Gurnett, D. A.; Kurth, W. S.; Cecconi, B. +3 more
Since Cassini entered Saturn's magnetosphere in July 2004, the auroral Saturnian kilometric radiation (SKR), which dominates the kronian radio spectrum, is observed quasi-continuously. Consecutive orbits of the spacecraft covered distances to Saturn down to 1.3 Saturn radii, all local times and, since December 2006, latitudes as high as 60°. On th…
X-ray spectra from magnetar candidates - I. Monte Carlo simulations in the non-relativistic regime
Zane, S.; Nobili, L.; Turolla, R.
The anomalous X-ray pulsars (AXPs) and soft γ-repeaters (SGRs) are peculiar high-energy sources believed to host a magnetar, an ultramagnetized neutron star with surface magnetic field in the petagauss range. Their persistent, soft X-ray emission exhibits a two component spectrum, usually modelled by the superposition of a blackbody and a power-la…
Hubble Space Telescope Morphologies of Local Lyman Break Galaxy Analogs. I. Evidence for Starbursts Triggered by Merging
Charlot, Stéphane; Aloisi, Alessandra; Heckman, Timothy M. +10 more
Heckman and coworkers used the GALEX UV imaging survey to show that there exists a rare population of nearby compact UV-luminous galaxies (UVLGs) that closely resemble high-redshift Lyman break galaxies (LBGs). We present HST images in the UV, optical, and Hα and resimulate them at the depth and resolution of the GOODS/UDF fields to show that the …
Are Optically Selected Quasars Universally X-Ray Luminous? X-Ray-UV Relations in Sloan Digital Sky Survey Quasars
Brandt, W. N.; Schneider, Donald P.; Gibson, Robert R.
We analyze archived Chandra and XMM-Newton X-ray observations of 536 Sloan Digital Sky Survey (SDSS) Data Release 5 (DR5) quasars (QSOs) at 1.7 <= z<= 2.7 in order to characterize the relative UV and X-ray spectral properties of QSOs that do not have broad UV absorption lines (BALs). We constrain the fraction of X-ray-weak, non-BAL QSOs and …
Variable winds on Venus mapped in three dimensions
Baines, K. H.; Hueso, R.; Sánchez-Lavega, A. +9 more
We present zonal and meridional wind measurements at three altitude levels within the cloud layers of Venus from cloud tracking using images taken with the VIRTIS instrument on board Venus Express. At low latitudes, zonal winds in the Southern hemisphere are nearly constant with latitude with westward velocities of 105 ms-1 at cloud-top…