Search Publications
First Direct Metallicity Measurement Of a Lensed Star-Forming Galaxy at z = 1.7
Yuan, T. -T.; Kewley, L. J.
We present the rest-frame optical spectrum of a strongly lensed galaxy at redshift z = 1.7 behind the cluster Abell 1689. We detect the temperature sensitive auroral line [O III] λ4363, which allows the first direct metallicity measurement for galaxies at z > 1. Our high signal-to-noise spectrum indicates that the target is an extremely low met…
Supersonic Downflows in a Sunspot Light Bridge
Venkatakrishnan, P.; Mathew, Shibu K.; Louis, Rohan E. +1 more
We report the discovery of supersonic downflows in a sunspot light bridge using measurements taken with the spectropolarimeter onboard the Hinode satellite. The downflows occur in small patches close to regions where the vector magnetic field changes orientation rapidly, and are associated with anomalous circular polarization profiles. An inversio…
The variability of Titan's magnetic environment
Dougherty, M. K.; Bertucci, C.; Arridge, C. S. +3 more
With a mean orbital radius of 20.2 Saturnian radii (1 Saturn radius RS=60,330 km), Titan is usually located within the kronian magnetosphere. 3.5 years of Cassini magnetometer observations in the vicinity of Titan's orbit reveal that the moon's magnetic environment is strongly affected by the presence of Saturn's magnetodisk. As a resul…
Rotation of White-light Coronal Mass Ejection Structures as Inferred from LASCO Coronagraph
Yurchyshyn, Vasyl; Abramenko, Valentyna; Tripathi, Durgesh
Understanding the connection between the magnetic configurations of a coronal mass ejection (CME) and their counterpart in the interplanetary medium is very important in terms of space weather predictions. Our previous findings indicate that the orientation of a halo CME elongation may correspond to the orientation of the underlying flux rope. Her…
Evolution of the early-type galaxy fraction in clusters since z = 0.8
Pelló, R.; White, S. D. M.; Milvang-Jensen, B. +13 more
We study the morphological content of a large sample of high-redshift clusters to determine its dependence on cluster mass and redshift. Quantitative morphologies are based on PSF-convolved, 2D bulge+disk decompositions of cluster and field galaxies on deep Very Large Telescope FORS2 images of eighteen, optically-selected galaxy clusters at 0.45 &…
Features around embedded moonlets in Saturn's rings: The role of self-gravity and particle size distributions
Lewis, Mark C.; Stewart, Glen R.
This paper presents the results of N-body simulations of moonlets embedded in broad rings, focusing specifically on the saturnian A ring. This work adds to previous efforts by including particle self-gravity and particle size distributions. The discussion here focuses primarily on the features that form in the background particles as a result of t…
Flows and Motions in Moss in the Core of a Flaring Active Region: Evidence for Steady Heating
Warren, Harry P.; Brooks, David H.
We present new measurements of the time variability of intensity, Doppler, and nonthermal velocities in moss in an active region core observed by the EUV Imaging Spectrometer on Hinode in 2007 June. The measurements are derived from spectral profiles of the Fe XII 195 Å line. Using the 2'' slit, we repeatedly scanned 150'' by 150'' in a few minute…
X-rays from the Explosion Site: 15 Years of Light Curves of SN 1993J
Chandra, Poonam; Pooley, David; Immler, Stefan +2 more
We present a comprehensive analysis of the X-ray light curves of supernova (SN) 1993J in a nearby galaxy M81. This is the only SN other than SN 1987A, which is so extensively followed in the X-ray bands. Here, we report on SN 1993J observations with Chandra in the year 2005 and 2008, and Swift observations in 2005, 2006, and 2008. We combined thes…
Atmospheric origin of cold ion escape from Mars
Barabash, S.; Lundin, R.; Holmström, M. +4 more
Cold ionospheric ions dominate the plasma escape from Mars. The flow pattern versus altitude, latitude and local time suggests a fairly symmetric transport of ionospheric plasma from the dayside into the nightside/tail region of Mars. An interesting aspect of the plasma escape from Mars is the large abundance of molecular ions, implying that the o…
Model atmospheres of chemically peculiar stars. Self-consistent empirical stratified model of HD 24712
Shulyak, D.; Ryabchikova, T.; Kochukhov, O. +1 more
Context: High-resolution spectra of some chemically peculiar stars clearly demonstrate the presence of strong abundance gradients in their atmospheres. However, these inhomogeneities are usually ignored in the standard scheme of model atmosphere calculations, breaking the consistency between model structure and spectroscopically derived abundance …