Search Publications
Chandra Discovery of a Binary Active Galactic Nucleus in Mrk 739
Sanders, D. B.; Schawinski, Kevin; Koss, Michael +6 more
We have discovered a binary active galactic nucleus (AGN) in the galaxy Mrk 739 using Chandra and Swift BAT. We find two luminous (L 2-10 keV = 1.1 × 1043 and 1.0 × 1042 erg s-1), unresolved nuclei with a projected separation of 3.4 kpc (5farcs8 ± 0farcs1) coincident with two bulge components in the opti…
Magnetic Helicity Spectrum of Solar Wind Fluctuations as a Function of the Angle with Respect to the Local Mean Magnetic Field
Podesta, J. J.; Gary, S. P.
Magnetic field data acquired by the Ulysses spacecraft in high-speed streams over the poles of the Sun are used to investigate the normalized magnetic helicity spectrum σ m as a function of the angle θ between the local mean magnetic field and the flow direction of the solar wind. This spectrum provides important information about the …
Weeds: a CLASS extension for the analysis of millimeter and sub-millimeter spectral surveys
Maret, S.; Pety, J.; Hily-Blant, P. +2 more
The advent of large instantaneous bandwidth receivers and high spectral resolution spectrometers on (sub-)millimeter telescopes has opened up the possibilities for unbiased spectral surveys. Because of the large amount of data they contain, any analysis of these surveys requires dedicated software tools. Here we present an extension of the widely …
Ice and Dust in the Quiescent Medium of Isolated Dense Cores
van Dishoeck, E. F.; Blake, G. A.; Decin, L. +6 more
The relation between ices in the envelopes and disks surrounding young stellar objects (YSOs) and those in the quiescent interstellar medium (ISM) is investigated. For a sample of 31 stars behind isolated dense cores, ground-based and Spitzer spectra and photometry in the 1-25 µm wavelength range are combined. The baseline for the broad and …
Formation timescales of large Martian valley networks
Hynek, Brian M.; Hoke, Monica R. T.; Tucker, Gregory E.
Assessing timescales for formation of the ancient Martian valley networks is key to interpreting the early climate on Mars. We determined the likely formation times for seven of the largest ancient valley networks on Mars using the Darcy-Weisbach equation for average flow velocity, three different sediment transport models, and a range of input pa…
A Massive Progenitor of the Luminous Type IIn Supernova 2010jl
Van Dyk, Schuyler D.; Filippenko, Alexei V.; Smith, Nathan +6 more
The bright, nearby, recently discovered supernova (SN) 2010jl is a luminous Type IIn SN. Here, we report archival Hubble Space Telescope (HST) observations of its host galaxy UGC 5189A taken roughly 10 yr prior to explosion, as well as early-time optical spectra of the SN. The HST images reveal a luminous, blue point source at the position of the …
Cluster Mass Profiles from a Bayesian Analysis of Weak-lensing Distortion and Magnification Measurements: Applications to Subaru Data
Broadhurst, Tom; Zitrin, Adi; Umetsu, Keiichi +2 more
We directly construct model-independent mass profiles of galaxy clusters from combined weak-lensing distortion and magnification measurements within a Bayesian statistical framework, which allows for a full parameter-space extraction of the underlying signal. This method applies to the full range of radius outside the Einstein radius, and recovers…
The Progenitor of Supernova 2011dh/PTF11eon in Messier 51
Van Dyk, Schuyler D.; Filippenko, Alexei V.; Cenko, S. Bradley +12 more
We have identified a luminous star at the position of supernova (SN) 2011dh/PTF11eon, in pre-SN archival, multi-band images of the nearby, nearly face-on galaxy Messier 51 (M51) obtained by the Hubble Space Telescope with the Advanced Camera for Surveys. This identification has been confirmed, to the highest available astrometric precision, using …
Global MHD Modeling of the Solar Corona and Inner Heliosphere for the Whole Heliosphere Interval
Riley, P.; Luhmann, J.; Linker, J. A. +3 more
In an effort to understand the three-dimensional structure of the solar corona and inner heliosphere during the Whole Heliosphere Interval (WHI), we have developed a global magnetohydrodynamics (MHD) solution for Carrington rotation (CR) 2068. Our model, which includes energy-transport processes, such as coronal heating, conduction of heat paralle…
Planck early results. XXI. Properties of the interstellar medium in the Galactic plane
Kneissl, R.; Miville-Deschênes, M. -A.; Boulanger, F. +199 more
Planck has observed the entire sky from 30 GHz to 857GHz. The observed foreground emission contains contributions from different phases of the interstellar medium (ISM). We have separated the observed Galactic emission into the different gaseous components (atomic, molecular and ionised) in each of a number of Galactocentric rings. This technique …