Search Publications
Tidal streams around galaxies in the SDSS DR7 archive. I. First results
Bomans, D. J.; Dettmar, R. -J.; Miskolczi, A.
Context. Models of hierarchical structure formation predict the accretion of smaller satellite galaxies onto more massive systems and this process should be accompanied by a disintegration of the smaller companions visible, e.g., in tidal streams.
Aims: In order to verify and quantify this scenario we have developed a search strategy for low …
The ACS Fornax Cluster Survey. X. Color Gradients of Globular Cluster Systems in Early-type Galaxies
Jordán, Andrés; Liu, Chengze; Côté, Patrick +4 more
We use the largest homogeneous sample of globular clusters (GCs), drawn from the ACS Virgo Cluster Survey (ACSVCS) and ACS Fornax Cluster Survey (ACSFCS), to investigate the color gradients of GC systems in 76 early-type galaxies. We find that most GC systems possess an obvious negative gradient in (g-z) color with radius (bluer outward), which is…
Discovery of Cold, Pristine Gas Possibly Accreting onto an Overdensity of Star-forming Galaxies at Redshift z ~ 1.6
Dickinson, Mark; Ferguson, Henry C.; Giavalisco, Mauro +11 more
We report the discovery of large amounts of cold (T ~ 104 K), chemically young gas in an overdensity of galaxies at redshift z ≈ 1.6 located in the Great Observatories Origins Deep Survey southern field. The gas is identified thanks to the ultra-strong Mg II λ2800 absorption features it imprints onto the rest-frame UV spectra of galaxie…
First simultaneous multi-wavelength observations of the black hole candidate IGR J17091-3624. ATCA, INTEGRAL, Swift, and RXTE views of the 2011 outburst
Tomsick, J. A.; Rodriguez, J.; Cadolle Bel, M. +5 more
We present the results of the first four (quasi-)simultaneous radio (ATCA), X-ray (Swift, RXTE), and γ-ray (INTEGRAL) observations of the black hole candidate IGR J17091-3624, performed in February and March 2011. The X-ray analysis shows that the source was in the hard state, and then it transited to a soft intermediate state. We study the correl…
The spectroscopic evolution of the symbiotic-like recurrent nova V407 Cygni during its 2010 outburst. I. The shock and its evolution
Shore, S. N.; Wahlgren, G. M.; Osborne, J. P. +7 more
Context. V407 Cyg was, before 2010 Mar., known only as a D-type symbiotic binary system in which the Mira variable has a pulsation period of approximately 750 days, one of the longest known. On 2010 Mar. 10, it was discovered in outburst, eventually reaching V < 8. This is the first recorded nova event for this system, but it closely resembles …
KK 246: A Dwarf Galaxy with an Extended H I Disk in the Local Void
Kreckel, K.; van der Hulst, J. M.; van Gorkom, J. H. +2 more
We have found that KK 246, the only confirmed galaxy located within the nearby Tully Void, is a dwarf galaxy with an extremely extended H I disk and signs of an H I cloud with anomalous velocity. It also exhibits clear misalignment between the kinematical major and minor axes, indicative of an oval distortion, and a general misalignment between th…
Atmospheric erosion of Venus during stormy space weather
Fedorov, A.; Barabash, S.; Futaana, Y. +9 more
We study atmospheric escape from Venus during solar minimum conditions when 147 corotating interaction regions (CIRs) and interplanetary coronal mass ejections (ICMEs) combined impact on the planet. This is the largest study to date of the effects of stormy space weather on Venus and we show for the first time statistically that the atmosphere of …
Dust formation in the ejecta of the type II-P supernova 2004dj
Balog, Z.; Kiss, L. L.; Vinkó, J. +3 more
Aims: Core-collapse supernovae (CC SNe), especially type II-Plateau ones, are thought to be important contributors to cosmic dust production. SN 2004dj, one of the closest and brightest SN since 1987A, offered a good opportunity to examine dust-formation processes. To find signs of newly formed dust, we analyze all available mid-infrared (MIR…
The Megaparsec-scale X-ray Jet of The BL Lac Object OJ287
Jorstad, Svetlana G.; Marscher, Alan P.
We present an X-ray image of the BL Lacertae (BL Lac) object OJ287 revealing a long jet, curved by 55° and extending 20'' or 90 kpc from the nucleus. This de-projects to >1 Mpc based on the viewing angle on parsec scales. Radio emission follows the general X-ray morphology but extends even farther from the nucleus. The upper limit to the isotro…
A layer of ozone detected in the nightside upper atmosphere of Venus
Vandaele, A. C.; Montmessin, F.; Fedorova, A. +7 more
To date, ozone has only been identified in the atmospheres of Earth and Mars. This study reports the first detection of ozone in the atmosphere of Venus by the SPICAV ultraviolet instrument onboard the Venus Express spacecraft. Venusian ozone is characterized by a vertically confined and horizontally variable layer residing in the thermosphere at …