Search Publications
Hubble Space Telescope Pre-perihelion ACS/WFC Imaging Polarimetry of Comet Ison (c/2012 s1) at 3.81 AU
Mutchler, Max; Muinonen, Karri; Hines, Dean C. +9 more
We present polarization images of Comet ISON (C/2012 S1) taken with the Hubble Space Telescope (HST) on UTC 2013 May 8 (r h = 3.81 AU, Δ = 4.34 AU), when the phase angle was α ≈ 12.°16. This phase angle is approximately centered in the negative polarization branch for cometary dust. The region beyond 1000 km (~0.32 arcsec ≈ 6 pixels) fr…
Strong Chromatic Microlensing in HE0047-1756 and SDSS1155+6346
Muñoz, J. A.; Mediavilla, E.; Rojas, K. +3 more
We use spectra of the double-lensed quasars HE0047-1756 and SDSS1155+6346 to study their unresolved structure through the impact of microlensing. There is no significant evidence of microlensing in the emission line profiles except for the Lyα line of SDSS1155+6346, which shows strong differences in the shapes for images A and B. However, the cont…
Neutral Interstellar Helium Parameters Based on Ulysses/GAS and IBEX-Lo Observations: What are the Reasons for the Differences?
Wood, B. E.; Katushkina, O. A.; Izmodenov, V. V. +1 more
Recent analysis of the interstellar helium fluxes measured in 2009-2010 at Earth's orbit by the Interstellar Boundary Explorer (IBEX) has suggested that the interstellar velocity (both direction and magnitude) is inconsistent with that derived previously from Ulysses/GAS observations made in the period from 1990 to 2002 at 1.5-5.5 AU from the Sun.…
Extreme Blazars Studied with Fermi-LAT and Suzaku: 1ES 0347-121 and Blazar Candidate HESS J1943+213
Cheung, C. C.; Fukazawa, Y.; Kataoka, J. +9 more
We report on our study of high-energy properties of two peculiar TeV emitters: the "extreme blazar" 1ES 0347-121 and the "extreme blazar candidate" HESS J1943+213 located near the Galactic plane. Both objects are characterized by quiescent synchrotron emission with flat spectra extending up to the hard X-ray range, and both were reported to be mis…
Interaction and Merging of two Sinistral Filaments
Liu, Yu; Wang, Haimin; Yang, Jiayan +4 more
In this paper, we report the interaction and subsequent merging of two sinistral filaments (F1 and F2) occurring at the boundary of AR 9720 on 2001 December 6. The two filaments were close and nearly perpendicular to each other. The interaction occurred after F1 was erupted and the eruption was impeded by a more extended filament channel (FC) stan…
The Inside-out Growth of the Most Massive Galaxies at 0.3 < z < 0.9
Gladders, M. D.; Yee, H. K. C.; Yan, Renbin +7 more
We study the surface brightness profiles of a sample of brightest cluster galaxies (BCGs) with 0.3 < z < 0.9. The BCGs are selected from the first Red-sequence Cluster Survey and an X-ray cluster survey. The surface brightness profiles of the BCGs are measured using HST ACS images, and the majority of them can be well modeled by a single Sér…
A Delayed Transition to the Hard State for 4U 1630-47 at the End of its 2010 Outburst
Kaaret, Philip; Yamaoka, Kazutaka; Kalemci, Emrah +3 more
Here we report on Swift and Suzaku observations near the end of an outburst from the black hole transient 4U 1630-47 and Chandra observations when the source was in quiescence. 4U 1630-47 made a transition from a soft state to the hard state ~50 days after the main outburst ended. During this unusual delay, the flux continued to drop, and one Swif…
Resolved Star Formation on Sub-galactic Scales in a Merger at z = 1.7
Rigby, Jane R.; Whitaker, Katherine E.; Brammer, Gabriel B. +4 more
We present a detailed analysis of Hubble Space Telescope (HST) Wide Field Camera 3 (WFC3) G141 grism spectroscopy for seven star-forming regions of the highly magnified lensed starburst galaxy RCSGA 032727-132609 at z = 1.704. We measure the spatial variations of the extinction in RCS0327 through the observed Hγ/Hβ emission line ratios, finding a …
Half-megasecond Chandra Spectral Imaging of the Hot Circumgalactic Nebula around Quasar Mrk 231
Maiolino, R.; Sturm, E.; Veilleux, S. +2 more
A deep 400 ks ACIS-S observation of the nearest quasar known, Mrk 231, is combined with archival 120 ks data to carry out the first ever spatially resolved spectral analysis of a hot X-ray-emitting circumgalactic nebula around a quasar. The 65 × 50 kpc X-ray nebula shares no resemblance with the tidal debris seen at optical wavelengths. One notabl…
An Estimate of the Coronal Magnetic Field near a Solar Coronal Mass Ejection from Low-frequency Radio Observations
Ramesh, R.; Kathiravan, C.; Hariharan, K. +2 more
We report ground-based, low-frequency (<100 MHz) radio imaging, spectral, and polarimeter observations of the type II radio burst associated with the solar coronal mass ejection (CME) that occurred on 2013 May 2. The spectral observations indicate that the burst has fundamental (F) and harmonic (H) emission components with split-band and herrin…