Search Publications
The Frequency of Binary Kuiper Belt Objects
Elliot, J. L.; Kern, S. D.
We estimate the frequency of widely spaced (separations greater than 0.5") Kuiper Belt binaries (KBBs) from surveys for new Kuiper Belt objects (KBOs) with the Deep Ecliptic Survey and through recovery observations for newly discovered KBOs at the Magellan telescopes. We find the frequency of KBBs versus discovery separation to be related by an in…
Small-Scale Anisotropy and Intermittence in High- and Low-Latitude Solar Wind
Velli, M.; Biferale, L.; Bigazzi, A. +1 more
We study low- and high-latitude fast solar wind data from the Ulysses spacecraft from 1992 to 1994 using for the first time a systematic method to analyze the anisotropic content of the magnetic field fluctuations beyond second-order correlation functions. We investigate all available frequencies, 1-10-6 Hz, for both high- and low-latit…
The Dust Envelope of the Preplanetary Nebula IRAS 19475+3119
Sahai, Raghvendra; Sarkar, Geetanjali
We present the spectral energy distribution (SED) of the preplanetary nebula, IRAS 19475+3119 (hereafter I 19475), from the optical to the far-infrared. We identify emission features due to crystalline silicates in the ISO SWS spectra of the star. We have fitted the SED of I 19475 using a one-dimensional radiative transfer code and find that a she…
Infalling Faint [O II] Emitters in Abell 851. II. Environment, Kinematics, and Star Formation History
Martin, Crystal L.; Sato, Taro
We report on the local environment, kinematics, and star formation history of [O II]-selected objects in the z~0.4 galaxy cluster Abell 851, using Keck optical spectra. A large fraction (~55%) of cluster [O II] emitters show strong Balmer absorptions (>~4 Å in Hδ equivalent width). These e(a)-type spectra have been attributed to dusty starburst…
The Outskirts of Spiral Galaxies: Evidence for Multiple Stellar Populations
Mouhcine, M.
We present an analysis of the metallicity distribution functions of fields projected along the minor axis for a sample of inclined spiral galaxies in order to search for evidence of the presence of multiple stellar populations. In all cases, with very high confidence levels, the stellar populations appear to have asymmetric metallicity distributio…
Very Cold and Massive Cores near ISOSS J18364-0221: Implications for the Initial Conditions of High-Mass Star Formation
Krause, O.; Birkmann, S. M.; Lemke, D.
We report the discovery of two very cold and massive molecular cloud cores in the region ISOSS J18364-0221. The object has been identified by a systematic search for very early evolutionary stages of high-mass stars using the 170 µm ISOPHOT Serendipity Survey (ISOSS). Submillimeter continuum and molecular line measurements reveal two compact…
Discovery of Hard X-Ray Delays in the X-Ray Emission of the Seyfert 1 Galaxy Markarian 110: Possible Evidence of Comptonization
Rao, A. R.; Dasgupta, Surajit
We report the discovery of hard X-ray delays in the X-ray emission of the Seyfert 1 galaxy Mrk 110, based on a long XMM-Newton observation. Cross-correlation between the X-ray light curves of different energy bands reveals an energy-dependent delay ranging from a few minutes to an hour. We find that the energy spectrum can be modeled by Comptoniza…
X-Rays from Radio Millisecond Pulsars: Comptonized Thermal Radiation
Bogdanov, Slavko; Grindlay, Jonathan E.; Rybicki, George B.
X-ray emission from many rotation-powered millisecond pulsars (MSPs) is observed to be of predominantly thermal nature. In PSR J0437-4715, the nearest MSP known, an additional faint power-law tail is observed above 2.5 keV, commonly attributed to nonthermal magnetospheric radiation. We propose that the hard emission in this and other similar MSPs …
Proper Motion of the Crab Pulsar Revisited
Ng, C. -Y.; Romani, Roger W.
It has been suggested that the Crab pulsar's proper motion is aligned with the symmetry axis of the pulsar wind nebula. We have revisited this question, examining >6 years of F547M WFPC2 chip 3 images to obtain a best-fit value of µ*=14.9+/-0.8 mas yr-1 at P.A. 278deg+/-3deg. At 26deg…
Integral Field Spectroscopy of the Extended Emission-Line Region of 3C 249.1
Fu, Hai; Stockton, Alan
We present Gemini Multiobject Spectrograph integral field spectroscopy of the extended emission-line region associated with quasar 3C 249.1. The kinematics of the ionized gas measured from the [O III] λ5007 line is rather complex and cannot be explained globally by a simple dynamical model, but some clouds can be modeled individually as having loc…