Search Publications
Venus Cloud Morphology and Motions from Ground-based Images at the Time of the Akatsuki Orbit Insertion
Hueso, R.; Sánchez-Lavega, A.; Rojas, J. F. +7 more
We report Venus image observations around the two maximum elongations of the planet at 2015 June and October. From these images we describe the global atmospheric dynamics and cloud morphology in the planet before the arrival of JAXA’s Akatsuki mission on 2015 December 7. The majority of the images were acquired at ultraviolet wavelengths (380-410…
The Gini Coefficient as a Tool for Image Family Idenitification in Strong Lensing Systems with Multiple Images
Sharon, Keren; Florian, Michael K.; Gladders, Michael D. +1 more
The sample of cosmological strong lensing systems has been steadily growing in recent years and with the advent of the next generation of space-based survey telescopes, the sample will reach into the thousands. The accuracy of strong lens models relies on robust identification of multiple image families of lensed galaxies. For the most massive len…
Dynamics of a Prominence-horn Structure during Its Evaporation in the Solar Corona
Liu, Wei; Li, Xing; Chen, Yao +3 more
The physical connections among and formation mechanisms of various components of the prominence-horn cavity system remain elusive. Here we present observations of such a system, focusing on a section of the prominence that rises and separates gradually from the main body. This forms a configuration sufficiently simple to yield clues regarding the …
Star Formation in Intermediate Redshift 0.2 < z < 0.7 Brightest Cluster Galaxies
Baum, Stefi A.; O'Dea, Christopher P.; Cooke, Kevin C. +3 more
We present a multi-wavelength photometric and spectroscopic study of 42 Brightest Cluster Galaxies (BCGs) in two samples of galaxy clusters chosen for a gravitational lensing study. The study’s initial sample combines 25 BCGs from the Cluster Lensing and Supernova Survey with Hubble sample and 37 BCGs from the Sloan Giant Arcs Survey with a total …
The Environment of z > 1 3CR Radio Galaxies and QSOs: From Proto-clusters to Clusters of Galaxies?
Macchetto, F. D.; Capetti, A.; Sparks, W. B. +8 more
We study the cluster environment for a sample of 21 radio loud active galactic nuclei from the 3CR catalog at z\gt 1, 12 radio galaxies (RGs) and nine quasars, with Hubble Space Telescope (HST) images in the optical and IR. We use two different approaches to determine cluster candidates. We identify the early-type galaxies (ETGs) in every field by…
The Secret Lives of Cepheids: Evolution, Mass-Loss, and Ultraviolet Emission of the Long-period Classical Cepheid
Guinan, Edward F.; Engle, Scott G.; Neilson, Hilding R. +2 more
The classical Cepheid l Carinae is an essential calibrator of the Cepheid Leavitt Law as a rare long-period Galactic Cepheid. Understanding the properties of this star will also constrain the physics and evolution of massive (M ≥ 8 M ⊙) Cepheids. The challenge, however, is precisely measuring the star's pulsation period and its rate of …
A Chandra Study of Temperature Distributions of the Intracluster Medium in 50 Galaxy Clusters
Hu, Dan; Xu, Haiguang; Zhu, Zhenghao +10 more
To investigate the spatial distribution of the intracluster medium temperature in galaxy clusters in a quantitative way and probe the physics behind it, we analyze the X-ray spectra from a sample of 50 clusters that were observed with the Chandra ACIS instrument over the past 15 years and measure the radial temperature profiles out to 0.45r50…
The Binary Black Hole Model for Mrk 231 Bites the Dust
Gallagher, Sarah C.; Terndrup, Donald M.; Leighly, Karen M. +1 more
Mrk 231 is a nearby quasar with an unusually red near-UV-to-optical continuum, generally explained as heavy reddening by dust. Yan et al. proposed that Mrk 231 is a milliparsec black hole binary with little intrinsic reddening. We show that if the observed FUV continuum is intrinsic, as assumed by Yan et al., it fails by a factor of about 100 in p…
Eta Carinae's Thermal X-Ray Tail Measured with XMM-Newton and NuSTAR
Hamaguchi, Kenji; Corcoran, Michael F.; Russell, Christopher M. P. +12 more
The evolved, massive highly eccentric binary system, η Car, underwent a periastron passage in the summer of 2014. We obtained two coordinated X-ray observations with XMM-Newton and NuSTAR during the elevated X-ray flux state and just before the X-ray minimum flux state around this passage. These NuSTAR observations clearly detected X-ray emission …
The Tale of the Two Tails of the Oldish PSR J2055+2539
De Luca, Andrea; Caraveo, Patrizia; Marelli, Martino +3 more
We analyzed a deep XMM-Newton observation of the radio-quiet γ-ray PSR J2055+2539. The spectrum of the X-ray counterpart is nonthermal, with a photon index of Γ = 2.36 ± 0.14 (1σ confidence). We detected X-ray pulsations with a pulsed fraction of 25% ± 3% and a sinusoidal shape. Taking into account considerations on the γ-ray efficiency of the pul…