Search Publications
Quiet-Sun Magnetic Fields from Space-borne Observations: Simulating Hinode's Case
Bellot Rubio, L. R.; del Toro Iniesta, J. C.; Orozco Suárez, D.
We examine whether it is possible to derive the field strength distribution of quiet-Sun internetwork regions from very high spatial resolution polarimetric observations in the visible. In particular, we consider the case of the spectropolarimeter attached to the Solar Optical Telescope aboard Hinode. Radiative magnetoconvection simulations are us…
The Fourth Positive System of Carbon Monoxide in the Hubble Space Telescope Spectra of Comets
Weaver, Harold A.; Feldman, Paul D.; Lupu, Roxana E. +1 more
The rich A1Π-X1Σ+ system of carbon monoxide accounts for most spectral features seen in long-slit HST STIS observations of comets 153P/Ikeya-Zhang, C/2001 Q4 (NEAT), and C/2000 WM1 (LINEAR), as well as in the HST GHRS spectrum of comet C/1996 B2 (Hyakutake). A detailed CO fluorescence model is developed …
X-Ray, UV, and Optical Observations of Supernova 2006bp with Swift: Detection of Early X-Ray Emission
Campana, S.; Pian, E.; Greiner, J. +21 more
We present results on the X-ray and optical/UV emission from the Type II-P supernova (SN) 2006bp and the interaction of the SN shock with its environment, obtained with the X-Ray Telescope (XRT) and UV/Optical Telescope (UVOT) on board Swift. SN 2006bp is detected in X-rays at a 4.5 σ level of significance in the merged XRT data from days 1 to 12 …
Spectral Evolution of NGC 1313 X-2: Evidence against the Cool Disk Model
Feng, Hua; Kaaret, Philip
The presence of a cool multicolor disk component with an inner disk temperature kT=~0.1-0.3 keV at a luminosity L>1040 ergs s-1 has been interpreted as evidence that the ultraluminous X-ray source NGC 1313 X-2 harbors an intermediate-mass black hole (IMBH). The temperature of a disk component should vary with luminosity as…
Probing Supergranular Flow in the Solar Interior
Woodard, M. F.
Helioseismic correlation data computed from SOHO MDI high-resolution Doppler images were inverted for solar subsurface supergranular flow, using an improved forward model. The statistical error of the inversion is set by the stochastic nature of solar wave excitation, which limits the detection of supergranular flow with these data to the first 4 …
A Comprehensive Study of the Initiation and Early Evolution of a Coronal Mass Ejection from Ultraviolet and White-Light Data
Romoli, M.; Bemporad, A.; Poletto, G. +1 more
In this work we analyze simultaneous UV and white-light (WL) observations of a slow CME that occurred on 2000 January 31. Unlike most CMEs studied in the UV so far, this event was not associated with a flare or filament eruption. Based on vector magnetograph data and magnetic field models, we find that field disruption in an active region (AR) was…
Confirming the Detection of an Intergalactic X-Ray Absorber toward PKS 2155-304
Canizares, Claude R.; Yao, Yangsen; Fang, Taotao
We present new observations of PKS 2155-304 with the Chandra Low Energy Transmission Grating (LETG), using the Advanced CCD Imaging Spectrometer (ACIS). We confirm the detection of an absorption line plausibly identified as O VIII Lyα from a warm-hot intergalactic medium associated with a small group of galaxies along the line of sight, as origina…
The Color-Magnitude Distribution of Field Galaxies to z~3: The Evolution and Modeling of the Blue Sequence
van Dokkum, Pieter G.; Franx, Marijn; Labbé, Ivo +7 more
Using deep NIR VLT ISAAC and optical HST WFPC2 imaging in the HDF-S and MS 1054-03, we study the rest-frame UV-to-optical colors and magnitudes of galaxies to z~3. Unlike the present day, there is no evidence for a red sequence at z~3, but there does appear to be a well-defined CMR for blue galaxies at all redshifts, with more luminous galaxies ha…
Measuring Flexion
Goldberg, David M.; Leonard, Adrienne
We describe practical approaches to measuring flexion in observed galaxies. In particular, we look at the issues involved in using the shapelets and HOLICs techniques as means of extracting second-order lensing information. We also develop an extension of HOLICs to estimate flexion in the presence of noise and with a nearly isotropic PSF. We test …
Observations of Dark Lanes in Umbral Fine Structure from the Hinode Solar Optical Telescope: Evidence for Magnetoconvection
Bharti, Lokesh; Joshi, Chandan; Jaaffrey, S. N. A.
An analysis of high-resolution G-band images of active region NOAA 10930 is presented. The observations were recorded with the Broadband Filter Imager (BFI) attached to the Solar Optical Telescope (SOT) on board the Hinode mission. We observed dark lanes in umbral dots up to six folds in larger ones. Formation of umbral dots from dark core penumbr…