Search Publications
Approximate Bayesian Computation for astronomical model analysis: a case study in galaxy demographics and morphological transformation at high redshift
Cameron, E.; Pettitt, A. N.
'Approximate Bayesian Computation' (ABC) represents a powerful methodology for the analysis of complex stochastic systems for which the likelihood of the observed data under an arbitrary set of input parameters may be entirely intractable - the latter condition rendering useless the standard machinery of tractable likelihood-based, Bayesian statis…
Global network of slow solar wind
Crooker, N. U.; Neugebauer, M.; Antiochos, S. K. +1 more
The streamer belt region surrounding the heliospheric current sheet (HCS) is generally treated as the primary or sole source of the slow solar wind. Synoptic maps of solar wind speed predicted by the Wang-Sheeley-Arge model during selected periods of solar cycle 23, however, show many areas of slow wind displaced from the streamer belt. These area…
The Near-infrared Background Intensity and Anisotropies during the Epoch of Reionization
Gong, Yan; Cooray, Asantha; Smidt, Joseph +1 more
A fraction of the extragalactic near-infrared (near-IR) background light involves redshifted photons from the ultraviolet (UV) emission from galaxies present during reionization at redshifts above 6. The absolute intensity and the anisotropies of the near-IR background provide an observational probe of the first-light galaxies and their spatial di…
Observation of interstellar lithium in the low-metallicity Small Magellanic Cloud
Mathews, Grant J.; Lehner, Nicolas; Howk, J. Christopher +1 more
The primordial abundances of light elements produced in the standard theory of Big Bang nucleosynthesis (BBN) depend only on the cosmic ratio of baryons to photons, a quantity inferred from observations of the microwave background. The predicted primordial 7Li abundance is four times that measured in the atmospheres of Galactic halo sta…
Titan's fluvial valleys: Morphology, distribution, and spectral properties
Sotin, C.; Barnes, J. W.; Brown, R. H. +11 more
Titan's fluvial channels have been investigated based on data obtained by the Synthetic Aperture Radar (SAR) instrument and the Visible and Infrared Mapping Spectrometer (VIMS) onboard the Cassini spacecraft. In this paper, a database of fluvial features is created based on radar-SAR data aiming to unveil the distribution and the morphologic and s…
Nonlinear Force-Free Extrapolation of Emerging Flux with a Global Twist and Serpentine Fine Structures
van Driel-Gesztelyi, L.; Démoulin, P.; Baker, D. +5 more
We study the flux emergence process in NOAA active region 11024, between 29 June and 7 July 2009, by means of multi-wavelength observations and nonlinear force-free extrapolation. The main aim is to extend previous investigations by combining, as much as possible, high spatial resolution observations to test our present understanding of small-scal…
A 10 kpc Scale Seyfert Galaxy Outflow: HST/COS Observations of IRAS F22456-5125
Kriss, Gerard A.; Arav, Nahum; Edmonds, Doug +2 more
We present analysis of the UV spectrum of the low-z AGN IRAS F22456-5125 obtained with the Cosmic Origins Spectrograph on board the Hubble Space Telescope. The spectrum reveals six main kinematic components, spanning a range of velocities of up to 800 km s-1, which for the first time are observed in troughs associated with C II, C IV, N…
The complete far-infrared and submillimeter spectrum of the Class 0 protostar Serpens SMM1 obtained with Herschel. Characterizing UV-irradiated shocks heating and chemistry
van Dishoeck, E. F.; Cernicharo, J.; Goicoechea, J. R. +8 more
We present the first complete ~55-671 µm spectral scan of a low-mass Class 0 protostar (Serpens SMM1) taken with the PACS and SPIRE spectrometers onboard Herschel. More than 145 lines have been detected, most of them rotationally excited lines of 12CO (full ladder from Ju = 4-3 to 42-41 and Eu/k = 4971 K), H<…
A Non-radial Eruption in a Quadrupolar Magnetic Configuration with a Coronal Null
Liu, Yang; Hayashi, Keiji; Sun, Xudong +2 more
We report one of the several homologous non-radial eruptions from NOAA active region (AR) 11158 that are strongly modulated by the local magnetic field as observed with the Solar Dynamic Observatory. A small bipole emerged in the sunspot complex and subsequently created a quadrupolar flux system. Nonlinear force-free field extrapolation from vecto…
Luminosity and mass functions of the three main sequences of the globular cluster NGC 2808
Anderson, J.; Milone, A. P.; Marino, A. F. +5 more
High-precision HST photometry has revealed that the globular cluster (GC) NGC 2808 hosts a triple main sequence (MS) corresponding to three stellar populations with different helium abundances. We carried out photometry on ACS/WFC HST images of NGC 2808 with the main purpose of measuring the luminosity function (LF) of stars in the three different…