Search Publications
Titan's Magnetic Field Signature During the First Cassini Encounter
Dougherty, Michele K.; Neubauer, Fritz M.; Russell, Christopher T. +8 more
The magnetic field signature obtained by Cassini during its first close encounter with Titan on 26 October 2004 is presented and explained in terms of an advanced model. Titan was inside the saturnian magnetosphere. A magnetic field minimum before closest approach marked Cassini's entry into the magnetic ionopause layer. Cassini then left the nort…
Evidence for Spectropolarimetric Diversity in Type Ia Supernovae
Filippenko, Alexei V.; Foley, Ryan J.; Leonard, Douglas C. +2 more
We present single-epoch, postmaximum spectropolarimetry of four Type Ia supernovae (SNe Ia) that span a range of spectral and photometric properties: SN 2002bf and SN 2004dt exhibit unusually high-velocity (HV) absorption lines. SN 1997dt is probably somewhat subluminous, and SN 2003du is slightly overluminous. We detect polarization modulations a…
The evolution of early-type galaxies at z ∼ 1 from the K20 survey
Cimatti, A.; Daddi, E.; di Serego Alighieri, S. +10 more
We have performed VLT spectroscopy of an almost complete sample of 18 early-type galaxies with 0.88≤ z≤ 1.3 plus two at z=0.67, selected from the K20 survey, and derived the velocity dispersion for 15+2 of them. By combining these data with HST and VLT images, we study the Fundamental Plane (FP), the Faber-Jackson and the Kormendy relations at z ∼…
High-resolution studies of radio sources in the Hubble Deep and Flanking Fields
Muxlow, T. W. B.; Richards, A. M. S.; Wilkinson, P. N. +8 more
18 days of MERLIN data and 42 h of A-array VLA data at 1.4 GHz have been combined to image a 10-arcmin field centred on the Hubble Deep Field (HDF). This area also includes the Hubble Flanking Fields (HFF). A complete sample of 92 radio sources with S1.4 > 40 µJy was detected using the VLA data alone and then imaged with the ME…
The T Tauri Star Population of the Young Cluster NGC 2264
Simon, Theodore; Dahm, S. E.
An Hα emission survey of the young cluster NGC 2264 in the Mon OB1 association resulted in the detection of 490 Hα emission stars in a 25'×40' field approximately centered between the O7 V multiple star S Mon and the Cone Nebula. The survey was carried out with the wide-field grism spectrograph (WFGS) on the University of Haw…
Magnetic field variations in the Jovian magnetotail induced by solar wind dynamic pressure enhancements
Yokoyama, Takaaki; Tao, Chihiro; Kataoka, Ryuho +2 more
In order to understand the response of the Jovian magnetosphere to solar wind dynamic pressure enhancements, we investigate magnetic field variations observed by the Galileo spacecraft. The lack of solar wind monitoring just upstream of the Jovian magnetosphere is overcome by simulating a one-dimensional magnetohydrodynamic (MHD) propagation of th…
The abundance discrepancy - recombination line versus forbidden line abundances for a northern sample of galactic planetary nebulae
Barlow, M. J.; Liu, X. -W.; Wesson, R.
We present deep optical spectra of 23 galactic planetary nebulae, which are analysed in conjunction with archival infrared and ultraviolet spectra. We derive nebular electron temperatures based on standard collisionally excited line (CEL) diagnostics as well as the hydrogen Balmer jump and find that, as expected, the Balmer jump almost always yiel…
Spatially resolved microwave pulsations of a flare loop
Melnikov, V. F.; Nakariakov, V. M.; Shibasaki, K. +1 more
A microwave burst with quasi-periodic pulsations was studied with high spatial resolution using observations with the Nobeyama Radioheliograph (NoRH). We found that the time profiles of the microwave emission at 17 and 34 GHz exhibit quasi-periodic (with two well defined periods P_1= 14-17 s and P_2= 8-11 s) variations of the intensity at differen…
Deep ACS Imaging of the Halo of NGC 5128: Reaching the Horizontal Branch
Greggio, Laura; Peng, Eric W.; Rejkuba, Marina +2 more
Using the Hubble Space Telescope (HST) Wide Field Camera (WFC) of the Advanced Camera for Surveys (ACS), we have obtained deep (V, I) photometry of an outer halo field in NGC 5128, to a limiting magnitude of I~=29. Our photometry directly reveals the core helium burning stellar population (the ``red clump'' or horizontal branch) in a giant E/S0 ga…
Discovery of the Accretion-powered Millisecond X-Ray Pulsar IGR J00291+5934
Chakrabarty, Deepto; Galloway, Duncan K.; Markwardt, Craig B. +2 more
We report on observations of the sixth accretion-powered millisecond pulsar, IGR J00291+5934, with the Rossi X-Ray Timing Explorer. The source is a faint recurrent X-ray transient initially identified by the International Gamma-Ray Astrophysics Laboratory. The 599 Hz (1.67 ms) pulsation had a fractional rms amplitude of 8% in the 2-20 keV range, a…