Search Publications
Formation of Pores Associated with the Inflow of Moving Magnetic Features
Zhang, Hongqi; Yang, Zhiliang; Li, Xiaobo
We investigate the formation of pores in NOAA AR 10930 associated with the inflow of moving magnetic features (MMFs) using simultaneous Hinode/Solar Optical Telescope filtergrams and magnetograms. The main results are outlined as follows: (1) the existence of MMFs around pores is a fairly common phenomenon. Around the four innate and one residue p…
G305.136+0.068: A Massive and Dense Cold Core in an Early Stage of Evolution
Pineda, Jaime E.; Garay, Guido; Mardones, Diego +3 more
We report molecular line observations, made with ASTE and SEST, and dust continuum observations at 0.87 mm, made with APEX, toward the cold dust core G305.136+0.068. The molecular observations show that the core is isolated and roughly circularly symmetric and imply that it has a mass of 1.1 × 103 M ⊙. A simultaneous model fi…
Was Comet C/1945 X1 (DU Toit) a Dwarf, SOHO-like Kreutz Sungrazer?
Sekanina, Zdenek; Kracht, Rainer
The goal of this investigation is to reinterpret and upgrade the astrometric and other data on comet C/1945 X1, the least prominent among the Kreutz system sungrazers discovered from the ground in the twentieth century. The central issue is to appraise the pros and cons of a possibility that this object is—despite its brightness reported at discov…
Better Alternatives to "Astronomical Silicate": Laboratory-based Optical Functions of Chondritic/Solar Abundance Glass with Application to HD 161796
Speck, A. K.; Pitman, K. M.; Hofmeister, A. M.
“Astronomical” or “circumstellar” silicate optical functions (real and imaginary indices of refraction n(λ ) and k(λ )) have previously been derived from compositionally and structurally disparate samples; past values were compiled from different sources in the literature, and are essentially kluges of observational, laboratory, and extrapolated o…
Statistical and Scaling Features of Fluctuations in the Dissipation Range During a Reconnection Event
Consolini, G.; Marcucci, M. F.; Pallocchia, G. +2 more
Reconnection events in space plasmas are accompanied by the occurrence of large-amplitude turbulent fluctuations of the magnetic and electric field, covering a wide range of temporal and spatial scales. Here, we study the scaling and statistical features of magnetic and electric field fluctuations below the ion-gyroperiod (i.e., in the dissipation…
On the Size and Mass of Photoionized Clouds in Extended Spiral Galaxy Halos
Danforth, Charles W.; Stocke, John T.; Keeney, Brian A. +1 more
The size and mass of two circumgalactic medium (CGM) clouds in the halo (impact parameter = 65 kpc) of a nearby late-type galaxy, MGC-01-04-005 ({cz}=1865 {km} {{{s}}}-1), are investigated using a close triplet of QSO sight lines (the “LBQS Triplet”). Far ultraviolet spectra obtained with the Cosmic Origins Spectrograph on board the Hub…
Mapping the Surface of the Magnetar 1E 1048.1-5937 in Outburst and Quiescence through Phase-resolved X-Ray Spectroscopy
Göğüş, Ersin; Güver, Tolga; Özel, Feryal
We model the pulse profiles and the phase-resolved spectra of the anomalous X-ray pulsar 1E 1048.1-5937 obtained with XMM-Newton to map its surface temperature distribution during an active and a quiescent epoch. We develop and apply a model that takes into account the relevant physical and geometrical effects on the neutron star surface, magnetos…
Internal Proper Motions in the Eskimo Nebula
López, J. A.; Steffen, W.; García-Díaz, Ma. T. +2 more
We present measurements of internal proper motions at more than 500 positions of NGC 2392, the Eskimo Nebula, based on images acquired with WFPC2 on board the Hubble Space Telescope at two epochs separated by 7.695 yr. Comparisons of the two observations clearly show the expansion of the nebula. We measured the amplitude and direction of the motio…
Physical Properties of a Pilot Sample of Spectroscopic Close Pair Galaxies at z ~ 2
Shapley, Alice E.; Steidel, Charles C.; Law, David R. +1 more
We use Hubble Space Telescope Wide-field Camera 3 rest-frame optical imaging to select a pilot sample of star-forming galaxies in the redshift range z = 2.00-2.65 whose multi-component morphologies are consistent with expectations for major mergers. We follow up this sample of major merger candidates with Keck/NIRSPEC long-slit spectroscopy obtain…
A Deep Herschel/PACS Observation of CO(40-39) in NGC 1068: A Search for the Molecular Torus
Lutz, D.; Genzel, R.; Poglitsch, A. +14 more
Emission from high-J CO lines in galaxies has long been proposed as a tracer of X-ray dominated regions (XDRs) produced by active galactic nuclei (AGNs). Of particular interest is the question of whether the obscuring torus, which is required by AGN unification models, can be observed via high-J CO cooling lines. Here we report on the analysis of …