Search Publications
Resonant Cyclotron Scattering in Magnetars' Emission
Götz, D.; Rea, N.; Lyutikov, M. +2 more
We present a systematic fit of a model of resonant cyclotron scattering (RCS) to the X-ray data of 10 magnetars, including canonical and transient anomalous X-ray pulsars (AXPs) and soft gamma repeaters (SGRs). In this scenario, nonthermal magnetar spectra in the soft X-rays (i.e., below ~10 keV) result from resonant cyclotron scattering of the th…
Figure of merit for dark energy constraints from current observational data
Wang, Yun
In order to make useful comparisons of different dark energy experiments, it is important to choose the appropriate figure of merit (FoM) for dark energy constraints. Here we show that for a set of dark energy parameters {fi}, it is most intuitive to define FoM=1/detCov(f1,f2,f3,…), where Cov(f1
Modeling Fe II Emission and Revised Fe II (UV) Empirical Templates for the Seyfert 1 Galaxy I Zw 1
Bruhweiler, F.; Verner, E.
We use the narrow-lined broad-line region (BLR) of the Seyfert 1 galaxy, I Zw 1, as a laboratory for modeling the ultraviolet (UV) Fe II 2100-3050 Å emission complex. We calculate a grid of Fe II emission spectra representative of BLR clouds and compare them with the observed I Zw 1 spectrum. Our predicted spectrum for log [nH/(cm …
Coronal mass ejections, type II radio bursts, and solar energetic particle events in the SOHO era
Kaiser, M. L.; Howard, R. A.; Gopalswamy, N. +5 more
Using the extensive and uniform data on coronal mass ejections (CMEs), solar energetic particle (SEP) events, and type II radio bursts during the SOHO era, we discuss how the CME properties such as speed, width and solar-source longitude decide whether CMEs are associated with type II radio bursts and SEP events. We discuss why some radio-quiet CM…
The Detailed Evolution of E+A Galaxies into Early Types
Zabludoff, Ann I.; Zaritsky, Dennis; Yang, Yujin +1 more
Poststarburst, or E+A, galaxies are the best candidates for galaxies in transition from being gas-rich and star-forming to gas-poor and passively evolving as a result of galaxy-galaxy interactions. To focus on what E+A galaxies become after their young stellar populations fade away, we present the detailed morphologies of 21 E+A galaxies using hig…
Spectroscopy, morphometry, and photoclinometry of Titan's dunefields from Cassini/VIMS
Sotin, Christophe; Barnes, Jason W.; Rodriguez, Sebastien +10 more
Fine-resolution (500 m/pixel) Cassini Visual and Infrared Mapping Spectrometer (VIMS) T20 observations of Titan resolve that moon's sand dunes. The spectral variability in some dune regions shows that there are sand-free interdune areas, wherein VIMS spectra reveal the exposed dune substrate. The interdunes from T20 are, variously, materials that …
On the distance to the Ophiuchus star-forming region
Mamajek, E. E.
The Ophiuchus molecular cloud complex has produced in Lynds 1688 the richest known embedded cluster within ∼300 pc of the Sun. Unfortunately, distance estimates to the Oph complex vary by nearly ∼40% (∼120-165 pc). Here I calculate a new independent distance estimate of 135 ± 8 pc to this benchmark star-forming region based on Hipparcos trigonomet…
Spectroscopic Confirmation of an Extreme Starburst at Redshift 4.547
Aussel, H.; Sanders, D. B.; Ilbert, O. +22 more
We report the spectroscopic confirmation of a submillimeter galaxy (SMG) at z = 4.547 with an estimated LIR = (0.5-2.0) × 1013 L⊙. The spectra, mid-IR, and X-ray properties indicate the bolometric luminosity is dominated by star formation at a rate of >1000 M⊙ yr-1. Multiple, spatially sepa…
Observations and modeling of a clumpy galaxy at z = 1.6. Spectroscopic clues to the origin and evolution of chain galaxies
Daddi, E.; Elbaz, D.; Bournaud, F. +7 more
We investigate the properties of a clump-cluster galaxy at redshift 1.57. In optical observations, the morphology of this galaxy is dominated by eight star-forming clumps, and its photometric properties are typical of most clump-cluster and chain galaxies. Its complex asymmetrical morphology has led to the suggestion that this system is a group me…
Lyman Break Galaxies, Lyα Emitters, and a Radio Galaxy in a Protocluster at z = 4.1
Ford, H. C.; Demarco, R.; Zheng, W. +17 more
We present deep HST ACS observations in g475r625i775z850 toward the z = 4.1 radio galaxy TN J1338-1942 and its overdensity of >30 spectroscopically confirmed Lyα emitters (LAEs). We select 66 g475 band dropouts to z850,5 σ = 27, 6 of which are also LAEs. Although our color-color …