Search Publications
Astrobiology and Venus exploration
Bullock, Mark A.; Grinspoon, David H.
For hundreds of years prior to the space age, Venus was considered among the most likely homes for extraterrestrial life. Since planetary exploration began, Venus has not been considered a promising target for Astrobiological exploration. However, Venus should be central to such an exploration program for several reasons. At present Venus is the o…
The Spectrum of the Black Hole X-Ray Nova V404 Cygni in Quiescence as Measured by XMM-Newton
Kong, Albert K. H.; Casares, J.; Haswell, C. A. +3 more
We present XMM-Newton observations of the black hole X-ray nova V404 Cyg in quiescence. Its quiescent spectrum can be best fitted by a simple power law with slope Γ~2. The spectra are consistent with that expected for the advection-dominated accretion flow (ADAF). V404 Cyg was roughly equal in luminosity compared to the previous observation of Cha…
Latest results on Jovian disk X-rays from XMM-Newton
Branduardi-Raymont, G.; Soria, R.; Waite, J. H. +6 more
We present the results of a spectral study of the soft X-ray emission (0.2-2.5 keV) from low-latitude ('disk') regions of Jupiter. The data were obtained during two observing campaigns with XMM-Newton in April and November 2003. While the level of the emission remained approximately the same between April and the first half of the November observa…
Reconstructing the history of dark energy using maximum entropy
Trotta, Roberto; Zunckel, Caroline
We present a Bayesian technique based on a maximum-entropy method to reconstruct the dark energy equation of state (EOS) w(z) in a non-parametric way. This Maximum Entropy (MaxEnt) technique allows to incorporate relevant prior information while adjusting the degree of smoothing of the reconstruction in response to the structure present in the dat…
The Young Cluster Population of M82 Region B
O'Connell, R. W.; Bastian, N.; Larsen, S. S. +6 more
We present observations obtained with the Advanced Camera for Surveys on board the Hubble Space Telescope of the ``fossil'' starburst region B in the nearby starburst galaxy M82. By comparing UBVI photometry with models, we derive ages and extinctions for 35 U-band-selected star clusters. We find that the peak epoch of cluster formation occurred ~…
X-ray emission from the young brown dwarfs of the Taurus molecular cloud
Ménard, F.; Audard, M.; Güdel, M. +9 more
Aims:We report the X-ray properties of young (~3 Myr) bona fide brown dwarfs of the Taurus Molecular Cloud (TMC).
Methods: The XMM-Newton Extended Survey of the TMC (XEST) is a large program designed to systematically investigate the X-ray properties of young stellar/substellar objects in the TMC. In particular, the area surveyed by 15 XMM-New…
The complex X-ray spectrum of the isolated neutron star RBS1223
Haberl, Frank; Schwope, Axel D.; Motch, Christian +1 more
We present a first analysis of a deep X-ray spectrum of the isolated neutron star RBS1223 obtained with XMM-Newton. Spectral data from four new monitoring observations in 2005/2006 were combined with archival observations obtained in 2003 and 2004 to form a spin-phase averaged spectrum containing 290 000 EPIC-pn photons. This spectrum shows higher…
A Radio through X-Ray Study of the Hot Spots, Active Nucleus, and Environment of the Nearby FR II Radio Galaxy 3C 33
Hardcastle, M. J.; Croston, J. H.; Birkinshaw, M. +4 more
We present results from Chandra ACIS-S, Spitzer, XMM-Newton, HST, and VLA observations of the radio hot spots, extended environment, and nucleus of the nearby (z=0.0597) FR II radio galaxy 3C 33. This is a relatively low power FR II radio galaxy, so we expect, a priori, to detect a significant X-ray synchrotron component to the emission from the h…
Three-dimensional Tomographic Analysis of a High-Cadence LASCO-C2 Polarized Brightness Sequence
Frazin, Richard A.; Kamalabadi, Farzad; Vásquez, Alberto M. +1 more
We present the first 3D tomographic reconstructions of the coronal electron density from an extended, high-cadence sequence of images of the corona's polarized brightness (pB). While the standard LASCO synoptic sequence is only 1 pB image per day, during the 14 day period covering 2006 June 9-22, the C2 coronagraph took about 6.5 pB images per day…
Imaging of the Stellar Population of IC 10 with Laser Guide Star Adaptive Optics and the Hubble Space Telescope
Graham, James R.; Vacca, William D.; Sheehy, Christopher D.
We present adaptive optics (AO) images of the central starburst region of the dwarf irregular galaxy IC 10. The Keck II telescope laser guide star was used to achieve near diffraction-limited performance at H and K' (Strehl ratios of 18% and 32%, respectively). The images are centered on the putative Wolf-Rayet (W-R) object [MAC92]24. W…