Search Publications
Pre-discovery Observations of Disrupting Asteroid P/2010 A2
Jewitt, David; Li, Jing; Stuart, Joseph S.
Solar system object P/2010 A2 is the first-noticed example of the aftermath of a recently disrupted asteroid, probably resulting from a collision. Nearly a year elapsed between its inferred initiation in early 2009 and its eventual detection in early 2010. Here, we use new observations to assess the factors underlying the visibility, especially to…
Recovering Swift-XRT energy resolution through CCD charge trap mapping
Campana, S.; Cusumano, G.; Moretti, A. +13 more
The X-ray telescope on board the Swift satellite for gamma-ray burst astronomy has been exposed to the radiation of the space environment since launch in November 2004. Radiation causes damage to the detector, with the generation of dark current and charge trapping sites that result in the degradation of the spectral resolution and an increase of …
"Hare and Hounds" Tests of Helioseismic Holography
Kosovichev, A. G.; Birch, A. C.; Braun, D. C. +1 more
We use the output of numerical wave-propagation simulations as synthetic data for "hare and hounds" tests of helioseismic holography. In the simple non-magnetic models examined here, we show that when the inversion method includes a consistent treatment of the filtering applied during the data analysis the inversions for the subsurface sound speed…
Multipoint observations of coronal mass ejection and solar energetic particle events on Mars and Earth during November 2001
Vennerstrom, S.; Falkenberg, T. V.; Brain, D. A. +2 more
Multipoint spacecraft observations provide unique opportunities to constrain the propagation and evolution of interplanetary coronal mass ejections (ICMEs) throughout the heliosphere. Using Mars Global Surveyor (MGS) data to study both ICME and solar energetic particle (SEP) events at Mars and OMNI and Geostationary Operational Environmental Satel…
Search for the Optical Counterpart to SGR 0418+5729
Pavlov, George G.; Kargaltsev, Oleg; Durant, Martin
We report broadband Hubble Space Telescope imaging of the field of soft γ-ray repeater SGR 0418+5729 with Advanced Camera for Surveys/Wide Field Channel and Wide Field Camera 3/IR. Observing in two wide filters, F606W and F110W, we find no counterpart within the positional error circle derived from Chandra observations, to limiting magnitudes m
Extreme warm absorber variability in the Seyfert galaxy Mrk 704
Bianchi, S.; Ponti, G.; Guainazzi, M. +8 more
Context. In about half of the Seyfert galaxies, the X-ray emission is absorbed by an optically thin, ionized medium, the so-called "warm absorber", whose origin and location is still a matter of debate.
Aims: The aim of this paper is to constrain the warm absorber further by studying its variability.
Methods: We analyzed the X-ray spectr…
Physical Properties of Large and Small Granules in Solar Quiet Regions
Yang, Shuhong; Zhang, Jun; Wang, Jingxiu +3 more
The normal mode observations of seven quiet regions obtained by the Hinode spacecraft are analyzed to study the physical properties of granules. An artificial intelligence technique is introduced to automatically find the spatial distribution of granules in feature spaces. In this work, we investigate the dependence of granular continuum intensity…
The 2008 outburst of IGR J17473-2721: evidence for a disk corona?
Torres, D. F.; Zhang, S.; Kretschmar, P. +4 more
Context. The 2008 outburst of the atoll source IGR J17473-2721 was observed by INTEGRAL, RXTE and Swift. Tens of type-I X-ray bursts were found in this outburst.
Aims: Joint observations by INTEGRAL, RXTE, and Swift provide sufficient data to look into the behavior of IGR J17473-2721 at the rising part of the 2008 outburst. The relation betwe…
The Quasar/Galaxy Pair PKS 1327-206/ESO 1327-2041: Absorption Associated with a Recent Galaxy Merger
Danforth, Charles W.; Stocke, John T.; Keeney, Brian A. +1 more
We present HST/WFPC2 broadband and ground-based Hα images, H I 21 cm emission maps, and low-resolution optical spectra of the nearby galaxy ESO 1327-2041, which is located 38'' (14 h -1 70 kpc in projection) west of the quasar PKS 1327-206. Our Hubble Space Telescope (HST) images reveal that ESO 1327-2041 has a complex optica…
The new carbon symbiotic star IPHAS J205836.43+503307.2
Munari, U.; Corradi, R. L. M.; Angeloni, R. +5 more
Aims: We are performing a search for symbiotic stars using IPHAS, the INT Hα survey of the northern Galactic plane, and follow-up observations.
Methods: Candidate symbiotic stars are selected on the basis of their IPHAS and near-IR colours, and spectroscopy and photometry are obtained to determine their nature. We present here observatio…