Search Publications
Association of solar wind proton flux extremes with pseudostreamers
Zhao, L.; Fisk, L. A.; Gibson, S. E.
We investigate the characteristics and solar origins of a subpopulation of the solar wind that possesses extreme values of proton flux. Ulysses observations including solar wind magnetic flux, proton flux, number density and velocity, and ionic composition are examined in this study. We find that the departures of solar wind proton flux from its c…
Finding η Car Analogs in Nearby Galaxies Using Spitzer. I. Candidate Selection
Kochanek, C. S.; Stanek, K. Z.; Khan, Rubab
The late-stage evolution of the most massive stars such as η Carinae is controlled by the effects of mass loss, which may be dominated by poorly understood eruptive mass ejections. Understanding this population is challenging because no true analogs of η Car have been clearly identified in the Milky Way or other galaxies. We utilize Spitzer IRAC i…
Comparison of solar horizontal velocity fields from SDO/HMI and Hinode data
Roudier, Th.; Malherbe, J. M.; Gizon, L. +7 more
Context. The measurement of the Sun's surface motions with a high spatial and temporal resolution is still a challenge.
Aims: We wish to validate horizontal velocity measurements all over the visible disk of the Sun from Solar Dynamics Observatory/ Helioseismic and Magnetic Imager (SDO/HMI) data.
Methods: Horizontal velocity fields are m…
Inverted-V and low-energy broadband electron acceleration features of multiple auroras within a large-scale surge
Karlsson, Tomas; Fazakerley, Andrew; Nilsson, Hans +9 more
Results are presented from a Cluster C2 satellite crossing through the acceleration region of multiple auroral structures within a large-scale surge, simultaneously monitored by DMSP F17 imager data. The magnetic and electric field data are consistent with the auroral distribution at large and medium scales. We identify the quasi-static accelerati…
The thermo-chemical evolution of Asteroid 21 Lutetia
Neumann, Wladimir; Breuer, Doris; Spohn, Tilman
In the present study, we model the thermo-chemical evolution of Asteroid 21 Lutetia using new data obtained by the Rosetta flyby in July 2010. We investigate the dependence of the evolution on the accretion onset time and duration for both instantaneous accretion and continuous accretion scenarios, assuming late runaway material accumulation. The …
The preferentially magnified active nucleus in IRAS F10214+4724 - II. Spatially resolved cold molecular gas
Heywood, I.; Deane, R. P.; Rawlings, S. +1 more
We present Jansky Very Large Array observations of the cold (CO (1→0)) molecular gas in IRAS F10214+4724, a lensed ultraluminous infraRed galaxy (ULIRG) at z = 2.3 with an obscured active nucleus. The galaxy is spatially and spectrally well resolved in the CO (1→0) emission line. The total intensity and velocity maps reveal a reasonably ordered sy…
PyGFit: A Tool for Extracting PSF Matched Photometry
Gonzalez, Anthony H.; Moustakas, Leonidas A.; Mancone, Conor L. +1 more
We present PyGFit, a program designed to measure PSF-matched photometry from images with disparate pixel scales and PSF sizes. While PyGFit has a number of uses, its primary purpose is to extract robust spectral energy distributions (SEDs) from crowded images. It does this by fitting blended sources in crowded, low resolution images with models ge…
Confronting brane inflation with Planck and pre-Planck data
Zhang, Xin; Huang, Qing-Guo; Ma, Yin-Zhe
In this paper, we compare brane inflation models with the Planck data and the pre-Planck data (which combines WAMP, ACT, SPT, BAO and H0 data). The Planck data prefer a spectral index less than unity at more than 5σ confidence level, and a running of the spectral index at around 2σ confidence level. We find that the KKLMMT model can sur…
Ultraviolet diagnostic of porosity-free mass-loss estimates in B stars
Prinja, R. K.; Massa, D. L.
Aims: We seek to establish evidence in UV P Cygni line profiles that the signs of wind clumping and porosity vary with velocity. We aim to demonstrate empirically that while at most wind velocities optically thick clumps cover only a fraction of the stellar surface, close to the terminal velocity (v∞) where narrow absorption compon…
Distribution of HNCO 505-404 in massive star-forming regions
Wang, J. Z.; Li, J.; Gu, Q. S. +1 more
Aims: The goal of this paper is to study the spatial distribution of HNCO in massive star-forming region and to investigate both its spatial association with infrared sources and physical conditions in region of HNCO emission.
Methods: We mapped nine massive star-forming regions in HNCO 505-404 with the Purple Mount…