Search Publications
Rapid Changes of Photospheric Magnetic Field after Tether-cutting Reconnection and Magnetic Implosion
Xu, Yan; Liu, Chang; Jing, Ju +6 more
The rapid, irreversible change of the photospheric magnetic field has been recognized as an important element of the solar flare process. This Letter reports such a rapid change of magnetic fields during the 2011 February 13 M6.6 flare in NOAA AR 11158 that we found from the vector magnetograms of the Helioseismic and Magnetic Imager (HMI) with 12…
Late-time Optical Emission from Core-collapse Supernovae
Chevalier, Roger A.; Kirshner, Robert P.; Challis, Peter +3 more
Ground-based optical spectra and Hubble Space Telescope images of 10 core-collapse supernovae (CCSNe) obtained several years to decades after outburst are analyzed with the aim of understanding the general properties of their late-time emissions. New observations of SN 1957D, 1970G, 1980K, and 1993J are included as part of the study. Blueshifted l…
On the Migration of Jupiter and Saturn: Constraints from Linear Models of Secular Resonant Coupling with the Terrestrial Planets
Lin, D. N. C.; Agnor, Craig B.
We examine how the late divergent migration of Jupiter and Saturn may have perturbed the terrestrial planets. Using a modified secular model we have identified six secular resonances between the ν5 frequency of Jupiter and Saturn and the four apsidal eigenfrequencies of the terrestrial planets (g 1-4). We derive analytic uppe…
Galaxy-scale Star Formation on the Red Sequence: The Continued Growth of S0s and the Quiescence of Ellipticals
Faber, S. M.; Salim, Samir; Rich, R. Michael +2 more
This paper examines star formation (SF) in relatively massive, primarily early-type galaxies (ETGs) at z ~ 0.1. A sample is drawn from bulge-dominated Galaxy Evolution Explorer/Sloan Digital Sky Survey (GALEX/SDSS) galaxies on the optical red sequence with strong UV excess and yet quiescent SDSS spectra. High-resolution far-UV imaging of 27 such E…
Photospheric Flux Cancellation and the Build-up of Sigmoidal Flux Ropes on the Sun
van Ballegooijen, A. A.; Green, L. M.; DeLuca, E. E. +1 more
In this study we explore the scenario of photospheric flux cancellation being the primary formation mechanism of sigmoidal flux ropes in decaying active regions. We analyze magnetogram and X-ray observations together with data-driven non-linear force-free field (NLFFF) models of observed sigmoidal regions to test this idea. We measure the total an…
Parsec-scale Radio Emission from the Low-luminosity Active Galactic Nucleus in the Dwarf Starburst Galaxy Henize 2-10
Deller, Adam T.; Reines, Amy E.
A candidate accreting massive black hole (BH) with M BH ~ 106 M ⊙ has recently been identified at the center of the dwarf starburst galaxy Henize 2-10 (He 2-10). This discovery offers the first possibility of studying a growing BH in a nearby galaxy resembling those in the earlier universe, and opens up a new class…
Evidence for Environmental Changes in the Submillimeter Dust Opacity
Devlin, Mark J.; Halpern, Mark; Miville-Deschênes, Marc-Antoine +25 more
The submillimeter opacity of dust in the diffuse interstellar medium (ISM) in the Galactic plane has been quantified using a pixel-by-pixel correlation of images of continuum emission with a proxy for column density. We used multi-wavelength continuum data: three Balloon-borne Large Aperture Submillimeter Telescope bands at 250, 350, and 500 &micr…
The Link between the Hidden Broad Line Region and the Accretion Rate in Seyfert 2 Galaxies
Goulding, Andy D.; Nicastro, Fabrizio; Bianchi, Stefano +2 more
In the past few years, more and more pieces of evidence have been presented for a revision of the widely accepted unified model of active galactic nuclei. A model based solely on orientation cannot explain all the observed phenomenology. In the following, we will present evidence that accretion rate is also a key parameter for the presence of hidd…
Reexamination of the Infrared Excess-Ultraviolet Slope Relation of Local Galaxies
Inoue, Akio K.; Murata, Katsuhiro L.; Takeuchi, Tsutomu T. +2 more
The relation between the ratio of infrared (IR) and ultraviolet (UV) flux densities (the infrared excess: IRX) and the slope of the UV spectrum (β) of galaxies plays a fundamental role in the evaluation of the dust attenuation of star-forming galaxies, especially at high redshifts. Many authors, however, have pointed out that there is a significan…
Sizing up Lyα and Lyman Break Galaxies
Finkelstein, Steven L.; Hathi, Nimish; Pirzkal, Norbert +4 more
We measure the sizes for a sample of 174 Lyα-selected galaxies with broadband imaging with the Hubble Space Telescope. Over the redshift range 2.25 < z < 6, Lyα-selected galaxies have a characteristic, constant, small size in rest-frame ultraviolet (UV) light. Coupled with a characteristic star formation intensity (i.e., UV luminosity per un…