Search Publications
The Cas A-like SNR 1E 0102.2-7219 in the Small Magellanic Cloud: An Asymmetric Bipolar Explosion
Dopita, Michael A.; Vogt, Frédéric
We have used the Wide Field Spectrograph on the 2.3 m telescope at Siding Spring Observatory to map the [O III] λ5007 dynamics of the young oxygen-rich supernova remnant 1E 0102.2-7219 in the Small Magellanic Cloud. From the resultant data cube, we have been able to reconstruct the full three-dimensional structure of the system of [O III] filament…
A Rising Cool Column as a Signature of Helical Flux Emergence and Formation of Prominence and Coronal Cavity
Tsuneta, Saku; Okamoto, Takenori J.; Berger, Thomas E.
Continuous observations were performed of a quiescent prominence with the Solar Optical Telescope on board the Hinode satellite on 2006 December 23 and 24. A peculiar slowly rising column of ~104 K plasma develops from the lower atmosphere during the observations. The apparent ascent speed of the column is 2 km s-1, while the…
Luminous X-ray Active Galactic Nuclei in Clusters of Galaxies
Plionis, M.; Koulouridis, E.
We present a study of X-ray active galactic nucleus (AGN) overdensities in 16 Abell clusters, within the redshift range 0.073 < z < 0.279, in order to investigate the effect of the hot inter-cluster environment on the triggering of the AGN phenomenon. The X-ray AGN overdensities, with respect to the field expectations, were estimated for sou…
Magnetic Energy Spectra in Solar Active Regions
Yurchyshyn, Vasyl; Abramenko, Valentyna
Line-of-sight magnetograms for 217 active regions (ARs) with different flare rates observed at the solar disk center from 1997 January until 2006 December are utilized to study the turbulence regime and its relationship to flare productivity. Data from the SOHO/MDI instrument recorded in the high-resolution mode and data from the BBSO magnetograph…
A Mature Dusty Star-forming Galaxy Hosting GRB 080607 at z = 3.036
Pettini, Max; Cenko, S. Bradley; Wilson, Christine D. +7 more
We report the discovery of the host galaxy of Swift dark burst GRB 080607 at z GRB = 3.036. GRB 080607 is a unique case of a highly extinguished (AV ≈ 3 mag) afterglow that was yet sufficiently bright for high-quality absorption-line spectroscopy. The host galaxy is clearly resolved in deep Hubble Space Telescope (HST) WF3/IR…
Parsec-scale Bipolar X-ray Shocks Produced by Powerful Jets from the Neutron Star Circinus X-1
Brandt, W. N.; Wijnands, R.; Nowak, M. A. +10 more
We report the discovery of multi-scale X-ray jets from the accreting neutron star X-ray binary, Circinus X-1. The bipolar outflows show wide opening angles and are spatially coincident with the radio jets seen in new high-resolution radio images of the region. The morphology of the emission regions suggests that the jets from Circinus X-1 are runn…
Magnetic Field Topology and the Thermal Structure of the Corona over Solar Active Regions
DeRosa, Marc L.; Title, Alan M.; Schrijver, Carolus J.
Solar extreme ultraviolet (EUV) images of quiescent active-region coronae are characterized by ensembles of bright 1-2 MK loops that fan out from select locations. We investigate the conditions associated with the formation of these persistent, relatively cool, loop fans within and surrounding the otherwise 3-5 MK coronal environment by combining …
Breaking the σ8-Ω m Degeneracy Using the Clustering of High-z X-ray Active Galactic Nuclei
Basilakos, Spyros; Plionis, Manolis
The clustering of X-ray selected active galactic nuclei (AGNs) appears to be a valuable tool for extracting cosmological information. Using the recent high-precision angular clustering results of ~30,000 XMM-Newton soft (0.5-2 keV) X-ray sources, which have a median redshift of z ~ 1, and assuming a flat geometry, a constant in comoving coordinate…
Physical Origin of Differences Among Various Measures of Solar Meridional Circulation
Ulrich, Roger K.; Dikpati, Mausumi; Gilman, Peter A.
We show that systematic differences between surface Doppler and magnetic element tracking measures of solar meridional flow can be explained by the effects of surface turbulent magnetic diffusion. Feature-tracking speeds are lower than plasma speeds in low and mid latitudes, because magnetic diffusion opposes poleward plasma flow in low latitudes …
Dust is Forming Along the Red Giant Branch of 47 Tuc
Dalessandro, Emanuele; Ferraro, Francesco R.; Origlia, Livia +4 more
We present additional evidence that dust is really forming along the red giant branch (RGB) of 47 Tuc at luminosities ranging from above the horizontal branch to the RGB tip. The presence of dust had been inferred from an infrared excess in the (K - 8) color, with K measured from high spatial resolution ground-based near-IR photometry and "8" refe…