Search Publications
Multiwavelength Monitoring of the Dwarf Seyfert 1 Galaxy NGC 4395. IV. The Variable UV Absorption Lines
Laor, Ari; Baskin, Alexei
We report the detection of variable UV absorption lines in NGC 4395, based on UV observations with the HST STIS carried out in 2004 April and July as part of a reverberation-mapping campaign. Low-ionization lines of O I, N I, Si II, C II, and Fe II are present in the low-state spectra (2004 April) at a velocity vshift = - 250 km s-…
Rapid Cadence EUNIS-06 Observations of a He II Transient Brightening in the Quiet Sun
Brosius, Jeffrey W.; Thomas, Roger J.; Rabin, Douglas M.
We observed a transient brightening in the quiet Sun at rapid cadence (2.10 s) with the Extreme Ultraviolet Normal Incidence Spectrograph (EUNIS-06) sounding rocket instrument on 2006 April 12. The transient was visible only in He II at 303.78 Å (T ≈ 5 × 104 K), and its maximum temperature T was <4 × 105 K. Taking its line…
X-Ray Observations of Optically Selected Giant Elliptical-Dominated Galaxy Groups
Miller, Christopher J.; Nichol, Robert C.; Heitmann, Katrin +4 more
We present a combined optical and X-ray analysis of three optically selected X-ray-bright groups with giant elliptical galaxies in the center. These massive ellipticals were targeted for XMM-Newton X-ray observations on the basis of their large-velocity dispersions and their proximity to a nearby ROSAT X-ray source. In addition, these targets are …
Spatially Resolved Far-Ultraviolet Spectroscopy of the Nuclear Region of NGC 1068
Kriss, Gerard A.; Zheng, Wei; Wang, Jun-Xian +5 more
We carry out high-resolution FUSE spectroscopy of the nuclear region of NGC 1068. The first set of spectra was obtained with a 30'' square aperture that collected all emission from the narrow-line region. The data reveal a strong broad O VI component of FWHM ~3500 km s-1 and two narrow O VI λλ1031, 1037 components of ~350 km s-1
Ultrarelativistic Electrons in Jupiter's Inner Magnetosphere: First Observation of Angular Distributions in the 2.5 to 6 RJ Region
Armstrong, Thomas P.; Taherion, Saeed; Garrett, Henry B.
Jupiter has been recognized as a probable location of magnetically trapped ultrarelativistic electrons since its discovery as a source of polarized decimeter radio waves. A series of spacecraft (Pioneers 10 and 11, Voyagers 1 and 2, Ulysses, Cassini, and New Horizons) have flown by and orbited Jupiter with the goal of observing the trapped radiati…
Elemental Abundances of Energetic Particles within Magnetic Clouds Detected by Ulysses
Fränz, Markus; Krupp, Norbert; Woch, Joachim +1 more
The study of particles from the solar wind thermal population up to higher near-relativistic energies provides a tool to analyze and characterize the internal structure of magnetic clouds (MCs). In this work, we analyze the elemental composition of energetic particles at ~1 MeV nucleon-1. Statistically, using a data set of 40 MCs, we fi…
How Do f-Mode Frequencies Change with Solar Radius?
Antia, H. M.; Chatterjee, Piyali
We test the relation between relative f-mode frequency variation (δ ν/ν) and Lagrangian perturbation in the solar radius (δ r/r) obtained by Dziembowski and Goode using several pairs of solar models and show that it does not hold true for any of the model pairs we have used. We attempt to derive a better approximation for the kernel linking the re…
The FR II Broad-Line Seyfert 1 Galaxy: PKS J1037-2705
Clarke, Tracy E.; Punsly, Brian; Tingay, Steven +3 more
In this article we demonstrate that PKS J1037-2705 has a weak accretion flow luminosity, well below the Seyfert 1/QSO dividing line, weak broad emission lines (BELs), and moderately powerful FR II extended radio emission. It is one of the few documented examples of a broad-line object in which the time-averaged jet kinetic luminosity, \overline{Q}…
Constraints on the Velocity and Spatial Distribution of Helium-like Ions in the Wind of SMC X-1 from Observations with the XMM-Newton Reflection Grating Spectrometer
Kallman, Timothy R.; Liedahl, Duane A.; Wojdowski, Patrick S.
We present here X-ray spectra of the HMXB SMC X-1 obtained in an observation with the XMM-Newton observatory beginning before eclipse and ending near the end of eclipse. With RGS on board XMM-Newton, we observe emission lines from hydrogen-like and helium-like ions of nitrogen, oxygen, neon, magnesium, and silicon. Although the resolution of the R…
Is the Optically Unidentified Radio Source FIRST J121839.7+295325 a Dark Lens?
Keeton, C. R.; Ryan, R. E., Jr.; Windhorst, R. A. +2 more
We present evidence that the optically unidentified radio source FIRST J121839.7+295325 may be strongly lensing a background galaxy. We estimate the redshift of the assumed gravitational arc, discovered in parallel imaging with HST, from MMT-Blue Channel spectroscopy to be zarc = 2.48-0.05+0.14. We present lens mod…