Search Publications
The Extended Environment of M17: A Star Formation History
Bieging, John H.; Kang, Miju; Indebetouw, Rémy +9 more
M17 is one of the youngest and most massive nearby star-formation regions in the Galaxy. It features a bright H II region erupting as a blister from the side of a giant molecular cloud (GMC). Combining photometry from the Spitzer Galactic Legacy Infrared Mid-Plane Survey Extraordinaire (GLIMPSE) with complementary infrared (IR) surveys, we identif…
Modeling ionospheric outflows and their impact on the magnetosphere, initial results
Tóth, G.; Gombosi, T.; Glocer, A. +1 more
Ionospheric outflow has been shown to be a significant contributor to the plasma population of the magnetosphere during active geomagnetic conditions. We present the results of new efforts to model the source and effects of out-flowing plasma in the Space Weather Modeling Framework (SWMF). In particular, we develop and use the Polar Wind Outflow M…
1.75 h -1 kpc Separation Dual Active Galactic Nuclei at z = 0.36 in the Cosmos Field
Davis, Marc; Griffith, Roger L.; Stern, Daniel +4 more
We present strong evidence for dual active galactic nuclei (AGNs) in the z = 0.36 galaxy COSMOS J100043.15+020637.2. COSMOS Hubble Space Telescope (HST) imaging of the galaxy shows a tidal tail, indicating that the galaxy recently underwent a merger, as well as two bright point sources near the galaxy's center. The luminosities of these sources (d…
The Masses of Population II White Dwarfs
Bergeron, P.; Rich, R. Michael; Hansen, Brad M. S. +4 more
Globular star clusters are among the first stellar populations to have formed in the Milky Way, and thus only a small sliver of their initial spectrum of stellar types are still burning hydrogen on the main sequence today. Almost all of the stars born with more mass than 0.8 M sun have evolved to form the white dwarf cooling sequence of…
An optical spectroscopic survey of the 3CR sample of radio galaxies with z < 0.3. I. Presentation of the data
Macchetto, F. D.; Capetti, A.; Sparks, W. B. +4 more
We present a homogeneous and 92% complete dataset of optical nuclear spectra for the 113 3CR radio sources with redshifts <0.3, obtained with the Telescopio Nazionale Galileo. For these sources we could obtain uniform and uninterrupted coverage of the key spectroscopic optical diagnostics. The observed sample, including powerful classical FR II…
3D modelling of the colliding winds in η Carinae - evidence for radiative inhibition
Corcoran, M. F.; Hamaguchi, K.; Pittard, J. M. +2 more
The X-ray emission from the supermassive star ηCar is simulated using a 3D model of the wind-wind collision. In the model the intrinsic X-ray emission is spatially extended and energy dependent. Absorption due to the unshocked stellar winds and the cooled post-shock material from the primary LBV star is calculated as the intrinsic emission is ray …
Study on X-Ray Spectra of Obscured Active Galactic Nuclei Based on Monte Carlo Simulation—An Interpretation of Observed Wide-Band Spectra
Terashima, Yuichi; Ikeda, Shinya; Awaki, Hisamitu
Monte Carlo simulation is one of the best tools to study the complex spectra of Compton-thick active galactic nuclei (AGNs) and to figure out the relation between their nuclear structures and X-ray spectra. We have simulated X-ray spectra of Compton-thick AGNs obscured by an accretion torus whose structure is characterized by a half-opening angle,…
Discovery of an Unusual Optical Transient with the Hubble Space Telescope
Huang, X.; Lidman, C.; Amanullah, R. +27 more
We present observations of SCP 06F6, an unusual optical transient discovered during the Hubble Space Telescope Cluster Supernova Survey. The transient brightened over a period of ~100 days, reached a peak magnitude of ~ 21.0 in both i 775 and z 850, and then declined over a similar timescale. There is no host galaxy or progen…
Disk-Jet Connection in the Radio Galaxy 3C 120
Peterson, Bradley W.; McHardy, Ian M.; Gaskell, C. Martin +33 more
We present the results of extensive multi-frequency monitoring of the radio galaxy 3C 120 between 2002 and 2007 at X-ray (2-10 keV), optical (R and V bands), and radio (14.5 and 37 GHz) wave bands, as well as imaging with the Very Long Baseline Array (VLBA) at 43 GHz. Over the 5 yr of observation, significant dips in the X-ray light curve are foll…
How Complex is the Obscuration in Active Galactic Nuclei? New Clues from the Suzaku Monitoring of the X-Ray Absorbers in NGC 7582
Fiore, Fabrizio; Bianchi, Stefano; Piconcelli, Enrico +3 more
We present the results of a Suzaku monitoring campaign of the Seyfert 2 galaxy, NGC 7582. The source is characterized by very rapid (on timescales even lower than a day) changes of the column density of an inner absorber, together with the presence of constant components arising as reprocessing from a Compton-thick material. The best-fitting scena…