Search Publications
Analysis of Quiet-Sun Internetwork Magnetic Fields Based on Linear Polarization Signals
Bellot Rubio, L. R.; Orozco Suárez, D.
We present results from the analysis of Fe I 630 nm measurements of the quiet Sun taken with the spectropolarimeter of the Hinode satellite. Two data sets with noise levels of 1.2 × 10-3 and 3 × 10-4 are employed. We determine the distribution of field strengths and inclinations by inverting the two observations with a Milne-…
Investigating the Reliability of Coronal Emission Measure Distribution Diagnostics using Three-dimensional Radiative Magnetohydrodynamic Simulations
Testa, Paola; Martínez-Sykora, Juan; De Pontieu, Bart +2 more
Determining the temperature distribution of coronal plasmas can provide stringent constraints on coronal heating. Current observations with the Extreme ultraviolet Imaging Spectrograph (EIS) on board Hinode and the Atmospheric Imaging Assembly (AIA) on board the Solar Dynamics Observatory provide diagnostics of the emission measure distribution (E…
The First Maximum-light Ultraviolet through Near-infrared Spectrum of a Type Ia Supernova
Filippenko, Alexei V.; Foley, Ryan J.; Kirshner, Robert P. +21 more
We present the first maximum-light ultraviolet (UV) through near-infrared (NIR) Type Ia supernova (SN Ia) spectrum. This spectrum of SN 2011iv was obtained nearly simultaneously by the Hubble Space Telescope at UV/optical wavelengths and the Magellan Baade telescope at NIR wavelengths. These data provide the opportunity to examine the entire maxim…
Precursor of Sunspot Penumbral Formation Discovered with Hinode Solar Optical Telescope Observations
Shimizu, Toshifumi; Ichimoto, Kiyoshi; Suematsu, Yoshinori
We present observations of a precursory signature that would be helpful for understanding the formation process of sunspot penumbrae. The Hinode Solar Optical Telescope successfully captured the entire evolution of a sunspot from the pore to a large well-developed sunspot with penumbra in an emerging flux region appearing in NOAA Active Region 110…
Measuring the Solar Radius from Space during the 2003 and 2006 Mercury Transits
Kuhn, J. R.; Bush, R. I.; Emilio, M. +1 more
The Michelson Doppler Imager (MDI) aboard the Solar and Heliospheric Observatory observed the transits of Mercury on 2003 May 7 and 2006 November 8. Contact times between Mercury and the solar limb have been used since the seventeenth century to derive the Sun's size but this is the first time that high-quality imagery from space, above the Earth'…
The Location of Solar Metric Type II Radio Bursts with Respect to the Associated Coronal Mass Ejections
Ramesh, R.; Kathiravan, C.; Gopalswamy, N. +2 more
Forty-one solar type II radio bursts located close to the solar limb (projected radial distance r >~ 0.8 R ⊙) were observed at 109 MHz by the radioheliograph at the Gauribidanur observatory near Bangalore during the period 1997-2007. The positions of the bursts were compared with the estimated location of the leading edge (LE) of the…
A Type Ia Supernova at Redshift 1.55 in Hubble Space Telescope Infrared Observations from CANDELS
Ferguson, Henry C.; Grogin, Norman A.; Weiner, Benjamin J. +23 more
We report the discovery of a Type Ia supernova (SN Ia) at redshift z = 1.55 with the infrared detector of the Wide Field Camera 3 (WFC3-IR) on the Hubble Space Telescope (HST). This object was discovered in CANDELS imaging data of the Hubble Ultra Deep Field and followed as part of the CANDELS+CLASH Supernova project, comprising the SN search comp…
The Three-dimensional Distribution of Dust in NGC 891
Bershady, Matthew A.; Schechtman-Rook, Andrew; Wood, Kenneth
We produce three-dimensional Monte Carlo radiative transfer models of the edge-on spiral galaxy NGC 891, a fast-rotating galaxy thought to be an analog to the Milky Way. The models contain realistic spiral arms and a fractal distribution of clumpy dust. We fit our models to Hubble Space Telescope images corresponding to the B and I bands, using sh…
Discovery and Early Multi-wavelength Measurements of the Energetic Type Ic Supernova PTF12gzk: A Massive-star Explosion in a Dwarf Host Galaxy
Vanderburg, Andrew; Filippenko, Alexei V.; Cenko, S. Bradley +46 more
We present the discovery and extensive early-time observations of the Type Ic supernova (SN) PTF12gzk. Our light curves show a rise of 0.8 mag within 2.5 hr. Power-law fits (f(t)vprop(t - t 0) n ) to these data constrain the explosion date to within one day. We cannot rule out a quadratic fireball model, but higher values of …
Observations of the near- to Mid-infrared Unidentified Emission Bands in the Interstellar Medium of the Large Magellanic Cloud
Onaka, Takashi; Sakon, Itsuki; Kaneda, Hidehiro +3 more
We present the results of near- to mid-infrared slit spectroscopic observations (2.55-13.4 µm) of the diffuse emission toward nine positions in the Large Magellanic Cloud with the infrared camera on board AKARI. The target positions are selected to cover a wide range of the intensity of the incident radiation field. The unidentified infrared…