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Magnetic Reconnection in the Solar Wind
Gosling, J. T.
It is only within the last 5 years that we have learned how to recognize the unambiguous signature of magnetic reconnection in the solar wind in the form of roughly Alfvénic accelerated plasma flows embedded within bifurcated magnetic field reversal regions (current sheets). This paper provides a brief overview of what has since been learned about…
Galactic cold cores. III. General cloud properties
Bernard, J. -P.; Falgarone, E.; Juvela, M. +15 more
Context. In the project galactic cold cores we are carrying out Herschel photometric observations of cold regions of the interstellar clouds as previously identified with the Planck satellite. The aim of the project is to derive the physical properties of the population of cold clumps and to study its connection to ongoing and future star formatio…
Diffuse Lyα haloes around Lyα emitters at z=3: do dark matter distributions determine the Lyα spatial extents?
Ouchi, M.; Yamada, T.; Matsuda, Y. +7 more
Using stacks of Lyα images of 2128 Lyα emitters (LAEs) and 24 proto-cluster UV-selected galaxies (LBGs) at z = 3.1, we examine the surface brightness profiles of Lyα haloes around high-z galaxies as a function of environment and UV luminosity. We find that the slopes of the Lyα radial profiles become flatter as the Mpc-scale LAE surface density in…
Mapping the cold dust temperatures and masses of nearby KINGFISH galaxies with Herschel
Roussel, H.; Armus, L.; Weiss, A. +18 more
Taking advantage of the unprecedented combination of sensitivity and angular resolution afforded by the Herschel Space Observatory at far-infrared and submillimetre wavelengths, we aim to characterize the physical properties of cold dust within nearby galaxies, as well as the associated uncertainties, namely the robustness of the parameters we der…
Sulfur chemistry in the middle atmosphere of Venus
Belyaev, Denis A.; Zhang, Xi; Yung, Yuk L. +2 more
Venus Express measurements of the vertical profiles of SO and SO 2 in the middle atmosphere of Venus provide an opportunity to revisit the sulfur chemistry above the middle cloud tops (∼58 km). A one dimensional photochemistry-diffusion model is used to simulate the behavior of the whole chemical system including oxygen-, hydrogen-, chl…
Keck Spectroscopy of Faint 3 < z < 7 Lyman Break Galaxies. III. The Mean Ultraviolet Spectrum at z ~= 4
Stark, Daniel P.; Ellis, Richard S.; Jones, Tucker
We present and discuss the mean rest-frame ultraviolet spectrum for a sample of 81 Lyman break galaxies (LBGs) selected to be B-band dropouts at z ~= 4. The sample is mostly drawn from our ongoing Keck/DEIMOS survey in the GOODS fields and augmented with archival Very Large Telescope data. In general, we find similar spectroscopic trends to those …
Blind Detections of CO J = 1-0 in 11 H-ATLAS Galaxies at z = 2.1-3.5 with the GBT/Zpectrometer
Ivison, R. J.; Frayer, D. T.; Clements, D. L. +29 more
We report measurements of the carbon monoxide ground state rotational transition (12C16O J = 1-0) with the Zpectrometer ultrawideband spectrometer on the 100 m diameter Green Bank Telescope. The sample comprises 11 galaxies with redshifts between z = 2.1 and 3.5 from a total sample of 24 targets identified by Herschel-ATLAS p…
The Primeval Populations of the Ultra-faint Dwarf Galaxies
Ferguson, Henry C.; Brown, Thomas M.; Geha, Marla +9 more
We present new constraints on the star formation histories of the ultra-faint dwarf (UFD) galaxies, using deep photometry obtained with the Hubble Space Telescope (HST). A galaxy class recently discovered in the Sloan Digital Sky Survey, the UFDs appear to be an extension of the classical dwarf spheroidals to low luminosities, offering a new front…
On the determination of the spin of the black hole in Cyg X-1 from X-ray reflection spectra
Fabian, A. C.; Miller, J. M.; Reynolds, C. S. +9 more
The spin of Cygnus X-1 is measured by fitting reflection models to Suzaku data covering the energy band 0.9-400 keV. The inner radius of the accretion disc is found to lie within 2 gravitational radii (rg=GM/c2), and a value of ? is obtained for the dimensionless black hole spin. This agrees with recent measurements using the…
New Hubble Space Telescope Observations of Heavy Elements in Four Metal-Poor Stars
Beers, Timothy C.; Roederer, Ian U.; Frebel, Anna +7 more
Elements heavier than the iron group are found in nearly all halo stars. A substantial number of these elements, key to understanding neutron-capture nucleosynthesis mechanisms, can only be detected in the near-ultraviolet. We report the results of an observing campaign using the Space Telescope Imaging Spectrograph on board the Hubble Space Teles…