Search Publications
Transient Spiral Arms from Far Out-of-equilibrium Gravitational Evolution
Sylos Labini, Francesco; Benhaiem, David; Joyce, Michael
We describe how a simple class of out-of-equilibrium, rotating, and asymmetrical mass distributions evolve under their self-gravity to produce a quasi-planar spiral structure surrounding a virialized core, qualitatively resembling a spiral galaxy. The spiral structure is transient, but can survive tens of dynamical times, and further reproduces qu…
Evidence for Binarity and Possible Disk Obscuration in Kepler Observations of the Pulsating RV Tau Variable DF Cygni
Stassun, Keivan G.; Somers, Garrett; Vega, Laura D. +2 more
The Kepler light curve of DF Cyg is unparalleled in precision and cadence for any RV Tau star to date, spanning a baseline of ∼4 years and clearly displaying the signature pulsating behavior of alternating deep and shallow minima as well as the long-term trend indicative of an RVb-type variable. We measure DF Cyg’s formal period (the time interval…
An XMM-Newton and NuSTAR Study of IGR J18214-1318: A Non-pulsating High-mass X-Ray Binary with a Neutron Star
Fürst, Felix; Pottschmidt, Katja; Wilms, Jörn +5 more
IGR J18214-1318, a Galactic source discovered by the International Gamma-Ray Astrophysics Laboratory, is a high-mass X-ray binary (HMXB) with a supergiant O-type stellar donor. We report on the XMM-Newton and NuSTAR observations that were undertaken to determine the nature of the compact object in this system. This source exhibits high levels of a…
The Relativistic Jet-accretion Flow-Wind Connection in Mrk 231
O'Dea, Christopher P.; Miniutti, Giovanni; Punsly, Brian +2 more
Long-term radio monitoring of the broad absorption line (BAL) quasar Mrk 231 at 17.6 GHz detected a strong flare in 2015. This triggered four epochs of Very Long Baseline Array (VLBA) observations from 8.4 to 43 GHz as well as three epochs of X-ray observations with NuSTAR and two with XMM over a 15 week period. Two ejected components were detecte…
Herschel and Hubble Study of a Lensed Massive Dusty Starbursting Galaxy at z ∼ 3
Ivison, R. J.; Frayer, D. T.; Cooray, A. +19 more
We present the results of combined deep Keck/NIRC2, HST/WFC3 near-infrared, and Herschel far-infrared observations of an extremely star-forming dusty lensed galaxy identified from the Herschel Astrophysical Terahertz Large Area Survey (H-ATLAS J133542.9+300401). The galaxy is gravitationally lensed by a massive WISE-identified galaxy cluster at z …
Magnetic Separatrix as the Source Region of the Plasma Supply for an Active-region Filament
Cao, Wenda; Yang, K.; Chen, P. F. +2 more
Solar filaments can be formed via chromospheric evaporation followed by condensation in the corona or by the direct injection of cool plasma from the chromosphere to the corona. We here confirm with high-resolution Hα data observed by the 1.6 m New Solar Telescope of the Big Bear Solar Observatory on 2015 August 21 that an active-region filament i…
Sunspot Light Walls Suppressed by Nearby Brightenings
Hou, Yijun; Yang, Shuhong; Zhang, Jun +3 more
Light walls, as ensembles of oscillating bright structures rooted in sunspot light bridges, have not been well studied, although they are important for understanding sunspot properties. Using the Interface Region Imaging Spectrograph and Solar Dynamics Observatory observations, here we study the evolution of two oscillating light walls each within…
Probing the Metal Enrichment of the Intergalactic Medium at z = 5-6 Using the Hubble Space Telescope
Fan, Xiaohui; Cai, Zheng; Finlator, Kristian +2 more
We test the galactic outflow model by probing associated galaxies of four strong intergalactic C IV absorbers at z = 5-6 using the Hubble Space Telescope (HST) Advanced Camera for Surveys (ACS) ramp narrowband filters. The four strong C IV absorbers reside at z = 5.74, 5.52, 4.95, and 4.87, with column densities ranging from N C IV = 1…
Star-forming Environments throughout the M101 Group
Mihos, J. Christopher; Harding, Paul; Watkins, Aaron E.
We present a multiwavelength study of star formation within the nearby M101 Group, including new deep Hα imaging of M101 and its two companions. We perform a statistical analysis of the Hα-to-FUV flux ratios in H II regions located in three different environments: M101's inner disk, M101's outer disk, and M101's lower-mass companion galaxy NGC 547…
Nearby Young, Active, Late-type Dwarfs in Gaia's First Data Release
Zuckerman, B.; Kastner, Joel H.; Rodriguez, David +3 more
The Galex Nearby Young Star Survey (GALNYSS) has yielded a sample of ∼2000 UV-selected objects that are candidate nearby (D≲ 150 {pc}), young (age ∼ 10-100 Myr), late-type stars. Here, we evaluate the distances and ages of the subsample of (19) GALNYSS stars with Gaia Data Release 1 (DR1) parallax distances D≤slant 120 {pc}. The overall youth of t…