Search Publications
Variable Intrinsic Absorption in Mrk 279
Scott, Jennifer E.; Kriss, Gerard A.; Quijano, Jessica Kim +5 more
We examine the variability in the intrinsic absorption in the Seyfert 1 galaxy Mrk 279 using three epochs of observations from the Far Ultraviolet Spectroscopic Explorer and two epochs of observations with the Space Telescope Imaging Spectrograph on the Hubble Space Telescope. Rather than finding simple photoionization responses of the absorbing g…
A Statistical Study of the Relationship Between the Transport Rate of Magnetic Helicity and Solar Flares
Tan, Baolin; Zhang, Yin; Yan, Yihua
We present a statistical study which is aimed at understanding the fact that some flares (type I flare) are associated with sharp variations of the transport rate of magnetic helicity (dH/dt) while others are not (type II flare). The sample consists of 49 M-class and X-class flares which were produced by nine isolated active regions. Using high te…
Evolutionary Status of 85 Pegasi
Lee, J.; Demarque, P.; Kim, Y. -C. +1 more
We have investigated the evolutionary status of the visual binary 85 Peg (HD 224930) using a high-resolution spectroscopic analysis and the astrometric calibration of the stellar parameters. In spite of well-determined stellar parameters from HIPPARCOS astrometry and from spectroscopy, 85 Peg has for a long time revealed peculiar properties when a…
Deconstructing Active Region AR10961 Using STEREO, Hinode, TRACE, and SOHO
Walsh, Robert W.; Marsh, M. S.; Noglik, Jane B. +1 more
Active region 10961 was observed over a five-day period (2007 July 2-6) by instrumentation on-board STEREO, Hinode, TRACE, and SOHO. As it progressed from Sun's center to the solar limb, a comprehensive analysis of the extreme ultraviolet, X-ray, and magnetic field data reveals clearly observable changes in the global nature of the region. Tempera…
Dynamics of Lyman Break Galaxies and Their Host Halos
Koo, David C.; Lowenthal, James D.; Simard, Luc +1 more
We present deep two-dimensional spectra of 22 candidate and confirmed Lyman break galaxies (LBGs) at redshifts 2 < z < 4 in the Hubble Deep Field (HDF) obtained at the Keck II telescope. The targets were preferentially selected with spatial extent and/or multiple knot morphologies, and we used slitmasks and individual slits tilted to optimiz…
Coronal Radiation Belts
Hudson, H. S.; MacKinnon, A. L.; De Rosa, M. L. +1 more
The magnetic field of the solar corona has a large-scale dipole character, which maps into the bipolar field in the solar wind. Using standard representations of the coronal field, we show that high-energy ions can be trapped stably in these large-scale closed fields. The drift shells that describe the conservation of the third adiabatic invariant…
A Chandra X-ray Observation of L1251B
Simon, Theodore
I report the results of a 60 ks X-ray observation of the L1251 dark cloud in Cepheus, which was acquired with the ACIS-I camera on board the Chandra X-Ray Observatory. Forty-three compact X-ray sources were detected. The field of view was centered on the position of IRAS 22376+7455, an embedded Class 0/I protostar that is closely associated with t…
UV Transient Brightenings Associated with a Coronal Mass Ejection
Romoli, M.; Poletto, G.; Schettino, G.
In this paper, we analyze transient UV brightenings in spectra acquired by SOHO/UltraViolet Coronagraph Spectrometer (UVCS) on 2003 June 2 in association with a coronal mass ejection (CME) that occurred at the West limb of the Sun at 08:54 UT. Brightenings have been observed in lines from cool (C III, O VI), intermediate (Si VIII, Si XII), and hig…
Footpoint Motions as Evidence for Patchy Reconnections in an M9.1 Solar Flare
Wang, Lin
We present an investigation on the UV footpoint motions of an M9.1 two-ribbon solar flare that occurred on 2004 July 22, employing the TRACE 1700 Å images and a magnetogram observed by SOHO/MDI. In the beginning, we found that the UV footpoints spread a two-dimensional distribution in, especially, the negative magnetic region, rather than a quasi-…
Signatures of Magnetic Stress Prior to Three Solar Flares Observed by RHESSI
Longcope, Dana; McLinden, Emily; des Jardins, Angela +2 more
We examine the hard X-ray (HXR) footpoint sources of three flares, as observed by RHESSI, in combination with the topology given by the extrapolation of line-of-sight magnetograms into the corona. Assuming the HXR footpoint sources are chromospheric consequences of magnetic reconnection that takes place on separators, we further assume a relations…