Search Publications
A New Photometric Technique for the Joint Selection of Star-forming and Passive Galaxies at 1.4 <~ z <~ 2.5
Cimatti, A.; Daddi, E.; Tozzi, P. +5 more
A simple two-color selection based on B-, z-, and K-band photometry is proposed for culling galaxies at 1.4<~z<~2.5 in K-selected samples and classifying them as star-forming or passive systems. The method is calibrated on the highly complete spectroscopic redshift database of the K20 survey, verified with simulations and tested on other dat…
The Second US Naval Observatory CCD Astrograph Catalog (UCAC2)
Zacharias, N.; Urban, S. E.; Wycoff, G. L. +4 more
The second US Naval Observatory (USNO) CCD Astrograph Catalog, UCAC2 was released in 2003 July. Positions and proper motions for 48,330,571 sources (mostly stars) are available on 3 CDs, supplemented with Two Micron All Sky Survey photometry for 99.5% of the sources. The catalog covers the sky area from -90° to +40° declination, going up to +52° i…
Transport of solar wind into Earth's magnetosphere through rolled-up Kelvin-Helmholtz vortices
Balogh, A.; Hasegawa, H.; Fujimoto, M. +5 more
Establishing the mechanisms by which the solar wind enters Earth's magnetosphere is one of the biggest goals of magnetospheric physics, as it forms the basis of space weather phenomena such as magnetic storms and aurorae. It is generally believed that magnetic reconnection is the dominant process, especially during southward solar-wind magnetic fi…
Detection of Oxygen and Carbon in the Hydrodynamically Escaping Atmosphere of the Extrasolar Planet HD 209458b
Ehrenreich, D.; Lecavelier des Etangs, A.; Ferlet, R. +7 more
Four transits of the planet orbiting the star HD 209458 were observed with the Space Telescope Imaging Spectrograph on board the Hubble Space Telescope. The wavelength domain (1180-1710 Å) includes H I as well as C I, C II, C IV, N V, O I, S I, Si II, Si III, and Si IV lines. During the transits, absorptions are detected in H I, O I, and C II (5%+…
ω Centauri: The Population Puzzle Goes Deeper
Anderson, Jay; Bedin, Luigi R.; Piotto, Giampaolo +4 more
We present Hubble Space Telescope observations that show a bifurcation of colors in the middle main sequence of the globular cluster ω Centauri. We see this in three different fields, observed with different cameras and filters. We also present high-precision photometry of a central Advanced Camera for Surveys field, which shows a number of main-s…
Detection of Methane in the Atmosphere of Mars
Encrenaz, Thérèse; Formisano, Vittorio; Giuranna, Marco +2 more
We report a detection of methane in the martian atmosphere by the Planetary Fourier Spectrometer onboard the Mars Express spacecraft. The global average methane mixing ratio is found to be 10 +/- 5 parts per billion by volume (ppbv). However, the mixing ratio varies between 0 and 30 ppbv over the planet. The source of methane could be either bioge…
Twenty-Three High-Redshift Supernovae from the Institute for Astronomy Deep Survey: Doubling the Supernova Sample at z > 0.7
Filippenko, Alexei V.; Wainscoat, Richard J.; Garnavich, Peter +29 more
We present photometric and spectroscopic observations of 23 high-redshift supernovae (SNe) spanning a range of z=0.34-1.03, nine of which are unambiguously classified as Type Ia. These SNe were discovered during the IfA Deep Survey, which began in 2001 September and observed a total of 2.5 deg2 to a depth of approximately m~25-26 in RIZ…
The Cassini Radio and Plasma Wave Investigation
Gurnett, D. A.; Hospodarsky, G. B.; Kurth, W. S. +27 more
The Cassini radio and plasma wave investigation is designed to study radio emissions, plasma waves, thermal plasma, and dust in the vicinity of Saturn. Three nearly orthogonal electric field antennas are used to detect electric fields over a frequency range from 1 Hz to 16 MHz, and three orthogonal search coil magnetic antennas are used to detect …
MeV Dark Matter: Has It Been Detected?
Silk, Joseph; Hooper, Dan; Paul, Jacques +2 more
We discuss the possibility that the recent detection of 511keV γ rays from the galactic bulge, as observed by INTEGRAL, is a consequence of low mass (1 100 MeV) particle dark matter annihilations. We discuss the type of halo profile favored by the observations as well as the size of the annihilation cross section needed to account for the signal. …
The Absence of Crystalline Silicates in the Diffuse Interstellar Medium
Tielens, A. G. G. M.; Kemper, F.; Vriend, W. J.
Infrared spectroscopy provides a direct handle on the composition and structure of interstellar dust. We have studied the dust along the line of sight toward the Galactic center using Short Wavelength Spectrometer data obtained with the Infrared Space Observatory (ISO). We focused on the wavelength region from 8 to 13 µm, which is dominated …