Search Publications
Molecular Signatures in the Near-Infrared Dayside Spectrum of HD 189733b
Deming, D.; Tinetti, G.; Bouwman, J. +5 more
We have measured the dayside spectrum of HD 189733b between 1.5 and 2.5 µm using the NICMOS instrument on the Hubble Space Telescope. The emergent spectrum contains significant modulation, which we attribute to the presence of molecular bands seen in absorption. We find that water (H2O), carbon monoxide (CO), and carbon dioxide (C…
History of Galaxy Interactions and Their Impact on Star Formation Over the Last 7 Gyr from GEMS
Papovich, Casey; Bell, Eric F.; Somerville, Rachel S. +22 more
We perform a comprehensive estimate of the frequency of galaxy mergers and their impact on star formation over z~ 0.24-0.80 (lookback time T b~ 3-7 Gyr) using ~3600 (M>= 1 × 109 M sun) galaxies with GEMS Hubble Space Telescope, COMBO-17, and Spitzer data. Our results are as follows. (1) Among ~790 high-mass (M&g…
A New Approach to Analyzing Solar Coronal Spectra and Updated Collisional Ionization Equilibrium Calculations. II. Updated Ionization Rate Coefficients
Savin, D. W.; Landi, E.; Bryans, P.
We have re-analyzed Solar Ultraviolet Measurement of Emitted Radiation (SUMER) observations of a parcel of coronal gas using new collisional ionization equilibrium (CIE) calculations. These improved CIE fractional abundances were calculated using state-of-the-art electron-ion recombination data for K-shell, L-shell, Na-like, and Mg-like ions of al…
Automated LASCO CME Catalog for Solar Cycle 23: Are CMEs Scale Invariant?
Berghmans, D.; Robbrecht, E.; Van der Linden, R. A. M.
In this paper, we present the first automatically constructed LASCO coronal mass ejection (CME) catalog, a result of the application of the Computer Aided CME Tracking software (CACTus) on the LASCO archive during the interval 1997 September-2007 January. We have studied the CME characteristics and have compared them with similar results obtained …
Bulge and Clump Evolution in Hubble Ultra Deep Field Clump Clusters, Chains and Spiral Galaxies
Elmegreen, Bruce G.; Elmegreen, Debra Meloy; Fernandez, Maria Ximena +1 more
Clump clusters and chain galaxies in the Hubble Ultra Deep Field (UDF) are examined for bulges in Near-Infrared Camera Multi-Object Spectrometer images. Approximately 50% of the clump clusters and 30% of the chains have relatively red and massive clumps that could be young bulges. Magnitudes and colors are determined for these bulgelike objects an…
Water, Methane, and Carbon Dioxide Present in the Dayside Spectrum of the Exoplanet HD 209458b
Burrows, A.; Tinetti, G.; Bouwman, J. +11 more
Using the NICMOS instrument on the Hubble Space Telescope, we have measured the dayside spectrum of HD 209458b between 1.5 and 2.5 µm. The emergent spectrum is dominated by features due to the presence of methane (CH4) and water vapor (H2O), with smaller contributions from carbon dioxide (CO2). Combining this…
Stellar-Mass Black Hole Spin Constraints from Disk Reflection and Continuum Modeling
Fabian, A. C.; Miller, J. M.; Reynolds, C. S. +2 more
Accretion disk reflection spectra, including broad iron emission lines, bear the imprints of the strong Doppler shifts and gravitational redshifts close to black holes. The extremity of these shifts depends on the proximity of the innermost stable circular orbit to the black hole, and that orbit is determined by the black hole spin parameter. Mode…
GRB 080913 at Redshift 6.7
Greiner, J.; McBreen, S.; Hartmann, D. H. +44 more
We report on the detection by Swift of GRB 080913, and subsequent optical/near-infrared follow-up observations by GROND, which led to the discovery of its optical/NIR afterglow and the recognition of its high-z nature via the detection of a spectral break between the i' and z' bands. Spectroscopy obtained at the ESO-VLT revealed a continuum extend…
Dependence of Solar-Wind Power Spectra on the Direction of the Local Mean Magnetic Field
Podesta, J. J.
Wavelet analysis can be used to measure the power spectrum of solar-wind fluctuations along a line in any direction (θ, phi) with respect to the local mean magnetic field B 0. This technique is applied to study solar-wind turbulence in high-speed streams in the ecliptic plane near solar minimum using magnetic field measurements with a c…
Estimating Black Hole Masses in Active Galactic Nuclei Using the Mg II λ2800 Emission Line
Ho, Luis C.; Yuan, Weimin; Zhou, Hongyan +6 more
We investigate the relationship between the linewidths of broad Mg II λ2800 and Hβ in active galactic nuclei (AGNs) to refine them as tools to estimate black hole (BH) masses. We perform a detailed spectral analysis of a large sample of AGNs at intermediate redshifts selected from the Sloan Digital Sky Survey, along with a smaller sample of archiv…