Search Publications
Clustering of i775 Dropout Galaxies at z ~ 6 in GOODS and the UDF
Franx, Marijn; Illingworth, Garth D.; Bouwens, Rychard J. +1 more
We measured the angular clustering at z~6 from a large sample of i775 dropout galaxies (293 with z850<=27.5 from GOODS and 95 with z850<=29.0 from the UDF). Our largest and most complete subsample (having L>~0.5L*z=6) shows the presence of clustering at 94% significance. For this samp…
Dependence of flux transfer events on solar wind conditions from 3 years of Cluster observations
Russell, C. T.; Lavraud, B.; Raeder, J. +6 more
We investigate the dependence of Cluster high-latitude magnetopause and low-latitude flank flux transfer events (FTEs) on solar wind conditions using measurements from Cluster FGM and CIS and ACE MFI and SWEPAM between February 2001 and June 2003. We find that there are strong dependences of Cluster FTE occurrence on the IMF Bxgsm, B
The Connection between Bar Strength and Circumnuclear Dust Structure
Martini, Paul; Peeples, Molly S.
We present a comparison of bar strength Qb and circumnuclear dust morphology for 75 galaxies in order to investigate how bars affect the centers of galaxies. We trace the circumnuclear dust morphology and amount of dust structure with structure maps generated from visible-wavelength HST data, finding that tightly wound nuclear dust spir…
Venus O + pickup ions: Collected PVO results and expectations for Venus Express
Luhmann, J. G.; Russell, C. T.; Lyon, J. G. +1 more
Observations of oxygen pickup ions by the plasma analyzer on the Pioneer Venus Orbiter (PVO) Mission arguably launched broad interest in solar wind erosion of unmagnetized planet atmospheres, and its potential evolutionary effects. Oxygen pickup ions may play key roles in the removal of the oxygen excess left behind from the photodissociation of w…
The Structure and Star Formation History of Early-Type Galaxies in the Ultra Deep Field/GRAPES Survey
Daddi, E.; Panagia, N.; Koekemoer, A. M. +9 more
We present a two-pronged approach to the formation of early-type galaxies, using a sample of 18 galaxies at 0.5<~z<~1 from the HST ACS Ultra Deep Field and GRAPES surveys: (1) We combine slitless low-resolution spectroscopy from the GRAPES data set with simple models of galaxy formation to explore their star formation histories. (2) We also …
The Pulsar Wind Nebula of the Geminga Pulsar
Pavlov, G. G.; Zavlin, V. E.; Sanwal, D.
The superb spatial resolution of Chandra has allowed us to detect a 20" long tail behind the Geminga pulsar, with a hard spectrum (photon index Γ=1.0+/-0.2) and a luminosity of (1.3+/-0.2)×1029 ergs s-1 in the 0.5-8 keV band, for an assumed distance of 200 pc. The tail could be either a pulsar jet, confined by a toroidal magn…
Spectroscopic Redshifts for Seven Lens Galaxies
Maoz, Dan; Rix, Hans-Walter; Kochanek, Christopher S. +2 more
The use of gravitationally lensed quasars for cosmological applications and as probes of galaxy structure and evolution requires knowledge about the lens redshift, which is unknown for a large fraction of lenses. We report Very Large Telescope observations of 11 lensed quasars, designed to measure the redshifts of their lens galaxies. We successfu…
Kinematics of Interstellar Gas in Nearby UV-selected Galaxies Measured with HST STIS Spectroscopy
Leitherer, C.; Oey, M. S.; Heckman, T. M. +3 more
We measure Doppler shifts of interstellar absorption lines in HST STIS spectra of individual star clusters in nearby UV-selected galaxies. Values for systemic velocities, which are needed to quantify outflow speeds, are taken from the literature and verified with stellar lines. We detect outflowing gas in 8 of 17 galaxies via low-ionization lines …
Precision Kinematics and Related Parameters of the α Persei Open Cluster
Makarov, Valeri V.
A kinematical study of the nearby open cluster α Persei is presented based on the astrometric proper motions and positions in the Tycho-2 catalog and Second USNO CCD Astrographic Catalog (UCAC2). Using the astrometric data and photometry from the Tycho-2 and ground-based catalogs, 139 probable members of the cluster are selected, 18 of them new. B…
Warm Water Vapor around Sagittarius B2
Cernicharo, José; Goicoechea, Javier R.; Pardo, Juan R. +1 more
Several condensations heated externally by nearby hot stars are present in the Sgr B2 region for which H2O far-IR lines are expected to probe only an external low-density and high temperature section. Millimeter-wave lines can penetrate deeper into them (higher densities and lower Tk). We have conducted a study combining H