Search Publications
First high-resolution detection of a warm absorber in the Broad Line Radio Galaxy 3C 382
Guainazzi, M.; Grandi, P.; Tombesi, F. +4 more
Recent high-resolution measurements suggest that the soft X-ray spectrum of obscured radio galaxies exhibits signatures of photoionized gas (e.g. 3C 445 and 3C 33) similar to those observed in radio-quiet obscured active galactic nuclei. While signatures of warm absorbing gas covering a wide range of temperature and ionization states have been det…
Asymmetry of solar polar fields and the southward shift of HCS observed by Ulysses
Mursula, K.; Virtanen, I. I.
We study the hemispheric asymmetry of high-latitude unipolar fields and the latitudinal shift of the heliospheric current sheet (HCS) using Ulysses magnetic field observations during the perihelion passes in 1994-1995, 2001-2002, and 2007. Using the cumulative flux density and the best fit lines to its high-latitude observations in the two hemisph…
LoCuSS: A Herschel view of obscured star formation in Abell 1835
Finoguenov, A.; Smith, G. P.; Okabe, N. +7 more
We present Herschel/PACS, MMT/Hectospec and XMM-Newton observations of Abell 1835, one of the brightest X-ray clusters on the sky, and the host of a strong cool core. Even though Abell 1835 has a prototypically “relaxed” X-ray morphology and no signs of ongoing merger activity in strong- and weak-lensing mass maps, it has a complex velocity distri…
Detection of Free Unstable Modes and Massive Bodies in Saturn's Outer B Ring
Porco, C. C.; Spitale, J. N.
Voyager images and Cassini occultation data have previously shown that the behavior of the outer edge of Saturn's massive B ring is determined only in part by a static response to the 2:1 inner Lindblad resonance with Mimas. In Cassini images of this region, we find, in addition to the expected wavenumber-2 forced distortion, evidence for unforced…
Absolute Timing of the Crab Pulsar with the INTEGRAL/SPI Telescope
Molkov, S.; Jourdain, E.; Roques, J. P.
We have investigated the pulse shape evolution of the Crab pulsar emission in the hard X-ray domain of the electromagnetic spectrum. In particular, we have studied the alignment of the Crab pulsar phase profiles measured in the hard X-rays and in other wavebands. To obtain the hard X-ray pulse profiles, we have used six years (2003-2009, with a to…
A census of nuclear stellar discs in early-type galaxies
Morelli, L.; Sarzi, M.; Dotti, M. +2 more
Nuclear stellar discs (NSDs), of a few tens to hundreds of parsec across, are a common and yet poorly studied feature of early-type galaxies. Still, such small discs represent a powerful tool to constrain the assembling history of galaxies, since they can be used to trace to the epoch when galaxies experienced their last major merger event. By stu…
The Star Cluster Population of the Collisional Ring Galaxy NGC 922
Knezek, Patricia M.; Meurer, Gerhardt R.; Elmegreen, Debra M. +3 more
We present a detailed study of the star cluster population detected in the galaxy NGC 922, one of the closest collisional ring galaxies known to date, using Hubble Space Telescope/Wide Field Planetary Camera 2 UBVI photometry, population synthesis models, and N-body/smoothed particle hydrodynamics simulations. We find that 69% of the clusters are …
Herschel/HIFI deepens the circumstellar NH3 enigma
Waters, L. B. F. M.; Menten, K. M.; Olofsson, H. +23 more
Context. Circumstellar envelopes (CSEs) of a variety of evolved stars have been found to contain ammonia (NH3) in amounts that exceed predictions from conventional chemical models by many orders of magnitude.
Aims: The observations reported here were performed in order to better constrain the NH3 abundance in the CSEs of…
Enstatite-rich Warm Debris Dust Around HD165014
Nakagawa, Takao; Onaka, Takashi; Ootsubo, Takafumi +6 more
We present the Spitzer/Infrared Spectrograph spectrum of the main-sequence star HD165014, which is a warm (gsim200 K) debris disk candidate discovered by the AKARI All-Sky Survey. The star possesses extremely large excess emission at wavelengths longer than 5 µm. The detected flux densities at 10 and 20 µm are ~10 and ~30 times larger …
Sunspot Rotation, Flare Energetics, and Flux Rope Helicity: The Halloween Flare on 2003 October 28
Qiu, Jiong; Longcope, Dana W.; Kazachenko, Maria D. +1 more
We study the X17 eruptive flare on 2003 October 28 using Michelson Doppler Imager observations of photospheric magnetic and velocity fields and TRACE 1600 Å images of the flare in a three-dimensional model of energy buildup and release in NOAA 10486. The most dramatic feature of this active region is the 123° rotation of a large positive sunspot o…