Search Publications
Kinematic properties of early-type galaxy haloes using planetary nebulae*
Freeman, K. C.; Capaccioli, M.; Napolitano, N. R. +11 more
We present new planetary nebulae (PNe) positions, radial velocities and magnitudes for six early-type galaxies obtained with the Planetary Nebulae Spectrograph (PNS), along with derived two-dimensional velocity and velocity dispersion fields, and the α parameters (i.e. the number of PNe per unit luminosity). We also present new deep absorption-lin…
Estimating Black Hole Masses in Active Galactic Nuclei Using the Mg II λ2800 Emission Line
Ho, Luis C.; Yuan, Weimin; Zhou, Hongyan +6 more
We investigate the relationship between the linewidths of broad Mg II λ2800 and Hβ in active galactic nuclei (AGNs) to refine them as tools to estimate black hole (BH) masses. We perform a detailed spectral analysis of a large sample of AGNs at intermediate redshifts selected from the Sloan Digital Sky Survey, along with a smaller sample of archiv…
A review of observed variability in the dayside ionosphere of Mars
Withers, Paul
Recent measurements by Mars Global Surveyor and Mars Express have greatly increased the number of observations of the martian dayside ionosphere available for study. Together with earlier measurements from the Viking era, these datasets have been used to investigate variations in well-known properties of the martian dayside ionosphere and to disco…
Negative ion chemistry in Titan's upper atmosphere
Lewis, G. R.; Coates, A. J.; Wahlund, J. -E. +5 more
The Electron Spectrometer (ELS), one of the sensors making up the Cassini Plasma Spectrometer (CAPS) revealed the existence of numerous negative ions in Titan's upper atmosphere. The observations at closest approach (∼1000 km) show evidence for negatively charged ions up to ∼10,000 amu/q, as well as two distinct peaks at 22±4 and 44±8 amu/q, and m…
Global Scale-Invariant Dissipation in Collisionless Plasma Turbulence
Sahraoui, F.; Dunlop, M. W.; Khotyaintsev, Yu. V. +2 more
A higher-order multiscale analysis of the dissipation range of collisionless plasma turbulence is presented using in situ high-frequency magnetic field measurements from the Cluster spacecraft in a stationary interval of fast ambient solar wind. The observations, spanning five decades in temporal scales, show a crossover from multifractal intermit…
Fomalhaut's Debris Disk and Planet: Constraining the Mass of Fomalhaut b from disk Morphology
Clampin, M.; Kite, E.; Kalas, P. +2 more
Following the optical imaging of exoplanet candidate Fomalhaut b (Fom b), we present a numerical model of how Fomalhaut's debris disk is gravitationally shaped by a single interior planet. The model is simple, adaptable to other debris disks, and can be extended to accommodate multiple planets. If Fom b is the dominant perturber of the belt, then …
Active Galactic Nucleus Host Galaxy Morphologies in COSMOS
Smolčić, V.; Jahnke, K.; Salvato, M. +14 more
We use Hubble Space Telescope/Advanced Camera for Surveys images and a photometric catalog of the Cosmic Evolution Survey (COSMOS) field to analyze morphologies of the host galaxies of ~400 active galactic nucleus (AGN) candidates at redshifts 0.3 < z < 1.0. We compare the AGN hosts with a sample of nonactive galaxies drawn from the COSMOS f…
GRB 080503: Implications of a Naked Short Gamma-Ray Burst Dominated by Extended Emission
Butler, N. R.; Sakamoto, T.; Bloom, J. S. +22 more
We report on observations of GRB 080503, a short gamma-ray burst (GRB) with very bright extended emission (about 30 times the gamma-ray fluence of the initial spike) in conjunction with a thorough comparison to other short Swift events. In spite of the prompt-emission brightness, however, the optical counterpart is extraordinarily faint, never exc…
The STAGES view of red spirals and dusty red galaxies: mass-dependent quenching of star formation in cluster infall
Papovich, Casey; Bell, Eric F.; Gallazzi, Anna +22 more
We investigate the properties of optically passive spirals and dusty red galaxies in the A901/2 cluster complex at redshift ~0.17 using rest-frame near-ultraviolet-optical spectral energy distributions, 24-µm infrared data and Hubble Space Telescope morphologies from the STAGES data set. The cluster sample is based on COMBO-17 redshifts with…
Detections of Lyman Continuum from Star-Forming Galaxies at z ~ 3 through Subaru/Suprime-Cam Narrow-Band Imaging
Burgarella, D.; Furusawa, H.; Yamada, T. +7 more
Knowing the amount of ionizing photons from young star-forming galaxies is of particular importance to understanding the reionization process. Here we report initial results of a Subaru/Suprime-Cam deep imaging observation of the SSA22 proto-cluster region at z = 3.09, using a special narrow-band filter to optimally trace ionizing radiation from g…