Search Publications

Understanding large SEP events with the PATH code: Modeling of the 13 December 2006 SEP event

Verkhoglyadova, O. P.; Cohen, C. M. S.; Mewaldt, R. A. +7 more

The Particle Acceleration and Transport in the Heliosphere (PATH) numerical code was developed to understand solar energetic particle (SEP) events in the near-Earth environment. We discuss simulation results for the 13 December 2006 SEP event. The PATH code includes modeling a background solar wind through which a CME-driven oblique shock propagat…

Magnetic field oscillations near the planetary period in Saturn's equatorial magnetosphere: Variation of amplitude and phase with radial distance and local time

Dougherty, M. K.; Andrews, D. J.; Cowley, S. W. H. +1 more

We present an analysis of the ∼11 h oscillations in Saturn's near-equatorial magnetic field, using Cassini data acquired during 2004-2007. We assume the oscillation period is given by the magnetic phase model derived by Provan et al. (2009) over the same interval, and use this to combine the data to determine the variation of the oscillation ampli…

Micro-sigmoids as Progenitors of Coronal Jets: Is Eruptive Activity Self-similarly Multi-scaled?

Raouafi, N. -E.; Georgoulis, M. K.; Rust, D. M. +1 more

Observations from the X-ray telescope (XRT) on Hinode are used to study the nature of X-ray-bright points, sources of coronal jets. Several jet events in the coronal holes are found to erupt from small-scale, S-shaped bright regions. This finding suggests that coronal micro-sigmoids may well be progenitors of coronal jets. Moreover, the presence o…

Abundances and Density Structure of the Inner Circumstellar Ring Around SN 1987A

Fransson, Claes; Lundqvist, Peter; Mattila, Seppo +4 more

We present optical spectroscopic data of the inner circumstellar ring around supernova (SN) 1987A from the Anglo-Australian Telescope and the Very Large Telescope (VLT) between ~1400 and ~5000 days post-explosion. We also assembled the available optical and near-infrared line fluxes from the literature between ~300 and ~2000 days. These line light…

Streamer Waves Driven by Coronal Mass Ejections

Chen, Y.; Li, B.; Song, H. Q. +4 more

Between 2004 July 5 and July 7, two intriguing fast coronal mass ejection (CME)-streamer interaction events were recorded by the Large Angle and Spectrometric Coronagraph. At the beginning of the events, the streamer was pushed aside from its equilibrium position upon the impact of the rapidly outgoing and expanding ejecta; then, the streamer stru…

Formation of NH3 and CH2NH in Titan's upper atmosphere

Smith, M. A.; Lavvas, P.; Vuitton, V. +4 more

Improved Constraints on the Gravitational Lens Q0957+561. II. Strong Lensing

Keeton, C. R.; Bernstein, G. M.; Nakajima, R. +1 more

We present a detailed strong lensing analysis of a Hubble Space Telescope/Advanced Camera for Surveys legacy data set for the first gravitational lens, Q0957+561. With deep imaging we identify 24 new strongly lensed features, which we use to constrain mass models. We model the stellar component of the lens galaxy using the observed luminosity dist…

``TNOs are cool'': A survey of the trans-Neptunian region. II. The thermal lightcurve of (136108) Haumea

Jorda, L.; Fornasier, S.; Groussin, O. +33 more

Thermal emission from Kuiper belt object (136108) Haumea was measured with Herschel-PACS at 100 µm and 160 µm for almost a full rotation period. Observations clearly indicate a 100 µm thermal lightcurve with an amplitude of a factor of ~2, which is positively correlated with the optical lightcurve. This confirms that both are pri…

Detection of Intra-day Variability Timescales of Four High-energy Peaked Blazars with XMM-Newton

Gupta, Alok C.; Wiita, Paul J.; Gaur, Haritma +1 more

We selected a sample of 24 XMM-Newton light curves (LCs) of four high energy peaked blazars, PKS 0548 - 322, ON 231, 1ES 1426+428, and PKS 2155 - 304. These data comprise continuous LCs of 7.67-18.97 hr in length. We searched for possible quasi-periodic oscillations (QPOs) and intra-day variability (IDV) timescales in the LCs of these blazars. We …

Weak Line Quasars at High Redshift: Extremely High Accretion Rates or Anemic Broad-line Regions?

Brandt, W. N.; Strauss, Michael A.; Anderson, Scott F. +9 more

We present Gemini-North K-band spectra of two representative members of the class of high-redshift quasars with exceptionally weak rest-frame ultraviolet emission lines (WLQs), SDSS J114153.34+021924.3 at z = 3.55 and SDSS J123743.08+630144.9 at z = 3.49. In both sources, we detect an unusually weak broad Hβ line and place tight upper limits on th…