Search Publications
Refinements in the data analysis of VIRTIS-M-IR Venus nightside spectra
Drossart, Pierre; Piccioni, Giuseppe; Haus, Rainer +2 more
The successful long-duration radiation measurements performed by the VIRTIS instrument aboard ESA's Venus Express spacecraft have provided an excellent collection of atmospheric and surface data that stand out due to their high temporal and spatial coverage of the planet and due to a high diversity of measurement and environmental conditions. A de…
Sublimation-driven erosion on Hyperion: Topographic analysis and landform simulation model tests
Schenk, Paul M.; White, Oliver L.; Moore, Jeffrey M. +2 more
The unique appearance of Hyperion can be explained in part by the loss to space of ballistic ejecta during impact events, as was proposed by Thomas et al. (Thomas, P.C. et al. [2007a]. Icarus 190, 573-584). We conclude that such loss is a partial explanation, accounting for the lack of appreciable intercrater plains on a saturation-cratered surfac…
GALEX-selected Lyman Break Galaxies at z ~ 2: Comparison with Other Populations
Nesvadba, N.; Haberzettl, L.; Lehnert, M. D. +2 more
We present results of a search for bright Lyman break galaxies (LBGs) at 1.5 <= z <= 2.5 in the GOODS-S field using an NUV-dropout technique in combination with color selection. We derived a sample of 73 LBG candidates. We compare our selection efficiencies to BM/BX and BzK methods (techniques solely based on ground-based data sets), and fin…
Possible optical counterpart of PSR J1357-6429
Mennickent, R. E.; Zharikov, S.; Kirichenko, A. +4 more
Context. PSR J1357-6429 is a Vela-like radio pulsar that has been recently detected in X-rays and γ-rays. It powers a compact tail-like X-ray pulsar wind nebula and X-ray-radio plerion associated with an extended TeV source HESS J1356-645.
Aims: We present our deep optical observations with the Very Large Telescope to search for an optical co…
CO and H2 Absorption in the AA Tauri Circumstellar Disk
Herczeg, Gregory J.; Brown, Alexander; France, Kevin +7 more
The direct study of molecular gas in inner protoplanetary disks is complicated by uncertainties in the spatial distribution of the gas, the time variability of the source, and the comparison of observations across a wide range of wavelengths. Some of these challenges can be mitigated with far-ultraviolet spectroscopy. Using new observations obtain…
X-Ray Binaries and Star Clusters in the Antennae: Optical Cluster Counterparts
Whitmore, Bradley C.; Chandar, Rupali; Rangelov, Blagoy +1 more
We compare the locations of 82 X-ray binaries (XRBs) detected in the merging Antennae galaxies by Zezas et al., based on observations taken with the Chandra X-Ray Observatory, with a catalog of optically selected star clusters presented by Whitmore et al., based on observations taken with the Hubble Space Telescope. Within the 2σ positional uncert…
The Panchromatic Hubble Andromeda Treasury. III. Measuring Ages and Masses of Partially Resolved Stellar Clusters
Bell, Eric F.; Gouliermis, Dimitrios A.; Dolphin, Andrew E. +14 more
The apparent age and mass of a stellar cluster can be strongly affected by stochastic sampling of the stellar initial mass function (IMF), when inferred from the integrated color of low-mass clusters (lsim104 M ⊙). We use simulated star clusters to show that these effects are minimized when the brightest, rapidly evolving sta…
A New Look at Solar Irradiance Variation
Foukal, Peter
We compare total solar irradiance (TSI) and ultraviolet (Fuv) irradiance variation reconstructed using Ca K facular areas since 1915, with previous values based on less direct proxies. Our annual means for 1925 - 1945 reach values 30 - 50 % higher than those presently used in IPCC climate studies. A high facula/sunspot area ratio in spo…
The Chandra Local Volume Survey: The X-Ray Point-source Catalog of NGC 300
Dalcanton, J. J.; Skillman, E. D.; Kong, A. K. H. +7 more
We present the source catalog of a new Chandra ACIS-I observation of NGC 300 obtained as part of the Chandra Local Volume Survey. Our 63 ks exposure covers ~88% of the D 25 isophote (R ≈ 6.3 kpc) and yields a catalog of 95 X-ray point sources detected at high significance to a limiting unabsorbed 0.35-8 keV luminosity of ~1036
[Fe III] Emission Lines in the Planetary Nebula NGC 2392
Zhang, Y.; Liu, X. -W.; Koning, N. +4 more
NGC 2392 is a young double-shell planetary nebula (PN). Its intrinsic structure and shaping mechanism are still not fully understood. In this paper we present new spectroscopic observations of NGC 2392. The slits were placed at two different locations to obtain the spectra of the inner and outer regions. Several [Fe III] lines are clearly detected…