Search Publications
Constraining AGN Feedback in Massive Ellipticals with South Pole Telescope Measurements of the Thermal Sunyaev-Zel'dovich Effect
Cohen, Seth; Joshi, Bhavin; Scannapieco, Evan +2 more
Energetic feedback due to active galactic nuclei (AGNs) is likely to play an important role in the observed anti-hierarchical trend in the evolution of galaxies, and yet the energy injected into the circumgalactic medium by this process is largely unknown. One promising approach to constrain this feedback is through measurements of spectral distor…
Material transport map of Titan: The fate of dunes
Lorenz, Ralph D.; Turtle, Elizabeth P.; Malaska, Michael J. +3 more
Using SAR data from Cassini's RADAR instrument, we examined the orientations of three terrain units on Titan, bright lineated plains, streak-like plains, and linear dunes. From the overall integrated pattern of their orientation, we were able to determine Titan's global material transport vectors. The analysis indicates that, in both the northern …
Seasonal variability of Saturn's tropospheric temperatures, winds and para-H2 from Cassini far-IR spectroscopy
Fletcher, Leigh N.; Irwin, P. G. J.; Orton, G. S. +2 more
Far-IR 16-1000 µ m spectra of Saturn's hydrogen-helium continuum measured by Cassini's Composite Infrared Spectrometer (CIRS) are inverted to construct a near-continuous record of upper tropospheric (70-700 mbar) temperatures and para-H2 fraction as a function of latitude, pressure and time for a third of a saturnian year (2004-20…
When Shock Waves Collide
Hartigan, P.; Frank, A.; Hansen, E. +10 more
Supersonic outflows from objects as varied as stellar jets, massive stars, and novae often exhibit multiple shock waves that overlap one another. When the intersection angle between two shock waves exceeds a critical value, the system reconfigures its geometry to create a normal shock known as a Mach stem where the shocks meet. Mach stems are impo…
Generation of magnetosonic waves over a continuous spectrum
Lu, Quanming; Gao, Xinliang; Zhima, Zeren +3 more
Magnetosonic waves, also known as equatorial noise emission, were found to have discrete frequency structures, which is consistent with instability caused by proton ring distribution. Nonetheless, nondiscrete structure, i.e., a broadband spectrum over a continuous frequency range, has been reported. We investigate the question whether proton ring …
The UV-Optical Color Gradients in Star-forming Galaxies at 0.5 < z < 1.5: Origins and Link to Galaxy Assembly
Barro, Guillermo; Faber, S. M.; Koo, David C. +10 more
The rest-frame UV-optical (I.e., NUV - B) color index is sensitive to the low-level recent star formation and dust extinction, but it is insensitive to the metallicity. In this Letter, we have measured the rest-frame NUV - B color gradients in ∼1400 large (r e > 0.″18), nearly face-on (b/a > 0.5) main sequence star-forming galaxie…
The multiplicity of 250-µm Herschel sources in the COSMOS field
Griffin, Matt; Oliver, Seb; Wang, Lingyu +5 more
We investigate the multiplicity of extragalactic sources detected by the Herschel Space Observatory in the COSMOS field. Using 3.6- and 24-µm catalogues, in conjunction with 250-µm data from Herschel, we seek to determine if a significant fraction of Herschel sources are composed of multiple components emitting at 250 µm. We use …
Discovery of a Makemakean Moon
Buie, Marc W.; Noll, Keith S.; Parker, Alex H. +1 more
We describe the discovery of a satellite in orbit about the dwarf planet (136472) Makemake. This satellite, provisionally designated S/2015 (136472) 1, was detected in imaging data collected with the Hubble Space Telescope’s Wide Field Camera 3 on UTC 2015 April 27 at 7.80 ± 0.04 mag fainter than Makemake and at a separation of 0.″57. It likely ev…
A New Perspective of the Radio Bright Zone at The Galactic Center: Feedback from Nuclear Activities
Morris, Mark R.; Goss, W. M.; Zhao, Jun-Hui
New observations of Sgr A have been carried out with the Jansky VLA in the B and C arrays using the broadband (2 GHz) continuum mode at 5.5 GHz. The field of view covers the central 13‧ (30 pc) region of the radio-bright zone at the Galactic center. Using the multi-scale and multi-frequency-synthesis (MS-MFS) algorithms in CASA, we have imaged Sgr…
Upholding the unified model for active galactic nuclei: VLT/FORS2 spectropolarimetry of Seyfert 2 galaxies
Hönig, S. F.; Tadhunter, C. N.; Acosta-Pulido, J. A. +5 more
The origin of the unification model for active galactic nuclei (AGN) was the detection of broad hydrogen recombination lines in the optical polarized spectrum of the Seyfert 2 galaxy (Sy2) NGC 1068. Since then, a search for the hidden broad-line region (HBLR) of nearby Sy2s started, but polarized broad lines have only been detected in ∼30-40 per c…