Search Publications
Metal Deficiency in Cluster Star-Forming Galaxies At Z = 2
Daddi, E.; Bournaud, F.; Juneau, S. +8 more
We investigate the environmental effect on the metal enrichment of star-forming galaxies (SFGs) in the farthest spectroscopically confirmed and X-ray-detected cluster, CL J1449+0856 at z = 1.99. We combined Hubble Space Telescope/WFC3 G141 slitless spectroscopic data, our thirteen-band photometry, and a recent Subaru/Multi-object InfraRed Camera a…
Structure and Formation of cD Galaxies: NGC 6166 in ABELL 2199
Kormendy, John; Bender, Ralf; Fisher, David B. +1 more
Hobby-Eberly Telescope (HET) spectroscopy is used to measure the velocity dispersion profile of the nearest prototypical cD galaxy, NGC 6166 in the cluster Abell 2199. We also present composite surface photometry from many telescopes. We confirm the defining feature of a cD galaxy; i.e., (we suggest), a halo of stars that fills the cluster center …
Quasi-periodic Pulsations in Solar and Stellar Flares: Re-evaluating their Nature in the Context of Power-law Flare Fourier Spectra
Dominique, M.; Ireland, J.; Inglis, A. R.
The nature of quasi-periodic pulsations (QPPs) in solar and stellar flares remains debated. Recent work has shown that power-law-like Fourier power spectra are an intrinsic property of solar and stellar flare signals, a property that many previous studies of this phenomenon have not accounted for. Hence a re-evaluation of the existing interpretati…
The formation of NGC 3603 young starburst cluster: `prompt' hierarchical assembly or monolithic starburst?
Kroupa, Pavel; Banerjee, Sambaran
The formation of very young massive clusters or `starburst' clusters is currently one of the most widely debated topic in astronomy. The classical notion dictates that a star cluster is formed in situ in a dense molecular gas clump. The stellar radiative and mechanical feedback to the residual gas energizes the latter until it escapes the system. …
On the 2012 October 23 Circular Ribbon Flare: Emission Features and Magnetic Topology
Ding, M. D.; Yang, Kai; Guo, Yang
Circular ribbon flares are usually related to spine-fan type magnetic topology containing null points. In this paper, we investigate an X-class circular ribbon flare on 2012 October 23, using the multiwavelength data from the Solar Dynamics Observatory, Hinode, and RHESSI. In Ca ii H emission, the flare showed three ribbons with two highly elongat…
A NuSTAR Survey of Nearby Ultraluminous Infrared Galaxies
Hailey, Charles J.; Alexander, D. M.; Koss, Michael +17 more
We present a Nuclear Spectroscopic Telescope Array (NuSTAR), Chandra, and XMM-Newton survey of nine of the nearest ultraluminous infrared galaxies (ULIRGs). The unprecedented sensitivity of NuSTAR at energies above 10 keV enables spectral modeling with far better precision than was previously possible. Six of the nine sources observed were detecte…
Quenching and morphological transformation in semi-analytic models and CANDELS
Papovich, Casey; Barro, Guillermo; Bell, Eric F. +9 more
We examine the spheroid growth and star formation quenching experienced by galaxies since z ∼ 3 by studying the evolution with redshift of the quiescent and spheroid-dominated fractions of galaxies from the CANDELS (Cosmic Assembly Near-infrared Deep Extragalactic Legacy Survey) and GAMA (Galaxy and Mass Assembly) surveys. We compare the observed …
The Interaction of Venus-like, M-dwarf Planets with the Stellar Wind of Their Host Star
Gombosi, T. I.; Drake, J. J.; Glocer, A. +4 more
We study the interaction between the atmospheres of Venus-like, non-magnetized exoplanets orbiting an M-dwarf star, and the stellar wind using a multi-species MHD model. We focus our investigation on the effect of enhanced stellar wind and enhanced EUV flux as the planetary distance from the star decreases. Our simulations reveal different topolog…
On the importance of using appropriate spectral models to derive physical properties of galaxies at 0.7 < z < 2.8
Charlot, Stéphane; Maseda, Michael V.; van Dokkum, Pieter G. +14 more
Interpreting observations of distant galaxies in terms of constraints on physical parameters - such as stellar mass (M★), star formation rate (SFR) and dust optical depth ({hat{τ}V}) - requires spectral synthesis modelling. We analyse the reliability of these physical parameters as determined under commonly adopted `classical…
The changing rotation period of comet 67P/Churyumov-Gerasimenko controlled by its activity
Jorda, L.; Keller, H. U.; Mottola, S. +1 more
Context. The ESA Rosetta spacecraft has been orbiting the nucleus of comet 67P/Churyumov-Gerasimenko since August 2014. The rotation axis of the irregularly shaped nucleus has a large obliquity (52°) and is oriented such that the southern hemisphere is insolated during perihelion.
Aims: We calculate the change in the rotation period as a func…