Search Publications
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…
A bright z = 5.2 lensed submillimeter galaxy in the field of Abell 773. HLSJ091828.6+514223
Smail, I.; Kneib, J. -P.; Smith, G. P. +20 more
During our Herschel Lensing Survey (HLS) of massive galaxy clusters, we have discovered an exceptionally bright source behind the z = 0.22 cluster Abell 773, which appears to be a strongly lensed submillimeter galaxy (SMG) at z = 5.2429. This source is unusual compared to most other lensed sources discovered by Herschel so far, because of its high…
Homogeneous studies of transiting extrasolar planets - V. New results for 38 planets
Southworth, John
I measure the physical properties of 38 transiting extrasolar planetary systems, bringing the total number studied within the Homogeneous Studies project to 82. Transit light curves are modelled using the jktebop code, with careful attention paid to limb darkening, orbital eccentricity and contaminating light. The physical properties of each syste…
A photochemical model for the Venus atmosphere at 47-112 km
Krasnopolsky, Vladimir A.
The model is intended to respond to the recent findings in the Venus atmosphere from the Venus Express and ground-based submillimeter and infrared observations. It extends down to 47 km for comparison with the kinetic model for the lower atmosphere (Krasnopolsky, V.A. [2007]. Icarus 191, 25-37) and to use its results as the boundary conditions. Th…
1H 0707-495 in 2011: an X-ray source within a gravitational radius of the event horizon
Schartel, N.; Santos-Lleó, M.; Fabian, A. C. +8 more
The narrow-line Seyfert 1 Galaxy 1H 0707-495 went into a low state from 2010 December to 2011 February, discovered by a monitoring campaign using the X-Ray Telescope on the Swift satellite. We triggered a 100 ks XMM-Newton observation of the source in 2011 January, revealing the source to have dropped by a factor of 10 in the soft band, below 1 ke…
Magnetic Reconnection in the Near Venusian Magnetotail
Coates, A. J.; Fedorov, A.; Barabash, S. +14 more
Observations with the Venus Express magnetometer and low-energy particle detector revealed magnetic field and plasma behavior in the near-Venus wake that is symptomatic of magnetic reconnection, a process that occurs in Earth’s magnetotail but is not expected in the magnetotail of a nonmagnetized planet such as Venus. On 15 May 2006, the plasma fl…