Search Publications
Crossing the Eddington Limit: Examining Disk Spectra at High Accretion Rates
Done, Chris; Soria, Roberto; Swartz, Douglas A. +3 more
The faintest ultraluminous X-ray sources (ULXs), those with 0.3-10 keV luminosities 1< {L}{{X}}/{10}39< 3 {erg} {{{s}}}-1, tend to have X-ray spectra that are disk-like but broader than expected for thin accretion disks. These “broadened disk (BD)” spectra are thought to indicate near- or mildly super-Eddingt…
Circumnuclear Structures in Megamaser Host Galaxies
Greene, Jenny E.; Seth, Anil C.; Henkel, Christian +4 more
Using the Hubble Space Telescope, we identify circumnuclear (100-500 pc scale) structures in nine new H2O megamaser host galaxies to understand the flow of matter from kpc-scale galactic structures down to the supermassive black holes (SMBHs) at galactic centers. We double the sample analyzed in a similar way by Greene et al. and consid…
A Large-scale Plume in an X-class Solar Flare
Fleishman, Gregory D.; Nita, Gelu M.; Gary, Dale E.
Ever-increasing multi-frequency imaging of solar observations suggests that solar flares often involve more than one magnetic fluxtube. Some of the fluxtubes are closed, while others can contain open fields. The relative proportion of nonthermal electrons among those distinct loops is highly important for understanding energy release, particle acc…
Effects of Solar Activity on the Local Interstellar Magnetic Field Observed by Voyager 1 and IBEX
McComas, D. J.; Schwadron, N. A.
Interstellar Boundary Explorer (IBEX) observations have shown enhanced energetic neutral atom emission from a narrow, circular ribbon likely centered on the direction of the magnetic field in the local interstellar medium (LISM). IBEX observations are compared to Voyager 1's direct observations of the magnetic field in the LISM, which reveals stru…
Imaging Observations of Magnetic Reconnection in a Solar Eruptive Flare
Sun, X.; Ding, M. D.; Li, Y. +2 more
Solar flares are among the most energetic events in the solar atmosphere. It is widely accepted that flares are powered by magnetic reconnection in the corona. An eruptive flare is usually accompanied by a coronal mass ejection, both of which are probably driven by the eruption of a magnetic flux rope (MFR). Here we report an eruptive flare on 201…
Coronal Jets Simulated with the Global Alfvén Wave Solar Model
Gombosi, T. I.; Toth, G.; Antiochos, S. K. +5 more
This paper describes a numerical modeling study of coronal jets to understand their effects on the global corona and their contribution to the solar wind. We implement jets into a well-established three-dimensional, two-temperature magnetohydrodynamic (MHD) solar corona model employing Alfvén-wave dissipation to produce a realistic solar-wind back…
Simultaneous Multiwavelength Observations of V404 Cygni during its 2015 June Outburst Decay Strengthen the Case for an Extremely Energetic Jet-base
Maccarone, Thomas J.; Grinberg, Victoria; Reynolds, Mark T. +4 more
We present results of multiband optical photometry of the black hole X-ray binary system V404 Cyg obtained using Wheaton College Observatory’s 0.3 m telescope, along with strictly simultaneous INTEGRAL and Swift observations during 2015 June 25.15-26.33 UT, and 2015 June 27.10-27.34 UT. These observations were made during the 2015 June outburst of…
Reverberation Mapping of PG 0934+013 with the Southern African Large Telescope
Barth, Aaron J.; Im, Myungshin; Jeon, Yiseul +10 more
We present the variability and time-lag measurements of PG 0934+013 based on a photometric and spectroscopic monitoring campaign over a two year period. We obtained 46 epochs of data from the spectroscopic campaign, which was carried out using the Southern African Large Telescope with ∼1 week cadence over two sets of four month-long observing peri…
A Spectroscopic Orbit for the Late-type Be Star β CMi
Wang, Luqian; Klement, Robert; Richardson, Noel D. +12 more
The late-type Be star β CMi is remarkably stable compared to other Be stars that have been studied. This has led to a realistic model of the outflowing Be disk by Klement et al. These results showed that the disk is likely truncated at a finite radius from the star, which Klement et al. suggest is evidence for an unseen binary companion in orbit. …
Evolution of Dust-obscured Star Formation and Gas to z = 2.2 from HiZELS
Thomson, A. P.; Smail, Ian; Ibar, E. +6 more
We investigate the far-infrared (far-IR) properties of galaxies selected via deep, narrow-band imaging of the Hα emission line in four redshift slices from z=0.40{--}2.23 over ∼1 deg2 as part of the High-redshift Emission Line Survey (HiZELS). We use a stacking approach in the Herschel PACS/SPIRE far-IR bands, along with 850 µ {{m…