Search Publications
Identification of Absorption Features in an Extrasolar Planet Atmosphere
Barman, T.
Water absorption is identified in the atmosphere of HD 209458b by comparing models for the planet's transmitted spectrum to recent, multiwavelength, eclipse-depth measurements (from 0.3 to 1 µm) published by Knutson et al. A cloud-free model that includes solar abundances, rainout of condensates, and photoionization of sodium and potassium i…
Physical Properties, Baryon Content, and Evolution of the Lyα Forest: New Insights from High-Resolution Observations at z <~ 0.4
Savage, B. D.; Wakker, B. P.; Sembach, K. R. +3 more
We present a study of the Lyα forest at z<~0.4, from which we conclude that at least 20% of the total baryons in the universe are located in the highly ionized gas traced by broad Lyα absorbers. The cool photoionized low-z intergalactic medium (IGM) probed by narrow Lyα absorbers contains about 30% of the baryons. We further find that the ratio…
Further Indications of Jet Rotation in New Ultraviolet and Optical Hubble Space Telescope STIS Spectra
Bacciotti, Francesca; Coffey, Deirdre; Eislöffel, Jochen +2 more
We present survey results that suggest rotation signatures at the base of T Tauri jets. Observations were conducted with the Hubble Space Telescope Imaging Spectrograph at optical and near-ultraviolet (NUV) wavelengths. Results are presented for the approaching jet from DG Tau, CW Tau, HH 30, and the bipolar jet from TH 28. Systematic asymmetries …
Warm Gas in the Inner Disks around Young Intermediate-Mass Stars
Simon, Theodore; Najita, Joan R.; Rettig, Terrence W. +1 more
The characterization of gas in the inner disks around young stars is of particular interest because of its connection to planet formation. In order to study the gas in inner disks, we have obtained high-resolution K- and M-band spectroscopy of 14 intermediate-mass young stars. In sources that have optically thick inner disks, i.e., E(K-L)>1, ou…
The Prelude to and Aftermath of the Giant Flare of 2004 December 27: Persistent and Pulsed X-Ray Properties of SGR 1806-20 from 1993 to 2005
Hurley, Kevin; Kouveliotou, Chryssa; Göǧüş, Ersin +5 more
We report on the evolution of key spectral and temporal parameters of SGR 1806-20 prior to and following the highly energetic giant flare of 2004 December 27. Using RXTE, we track the pulse frequency of the SGR and find that the spin-down rate varied erratically in the months before and after the flare. Contrary to the giant flare in SGR 1900+14, …
Evolution of the Luminosity Function, Star Formation Rate, Morphology, and Size of Star-forming Galaxies Selected at Rest-Frame 1500 and 2800 Å
Dickinson, Mark; Ferguson, Henry C.; Giavalisco, Mauro +4 more
Using the multiwavelength photometric and spectroscopic data covering the Chandra Deep Field South obtained within the Great Observatories Origins Deep Survey, we investigate the rest-frame UV properties of galaxies to z~2.2, including the evolution of the luminosity function, the luminosity density, star formation rate (SFR), and galaxy morpholog…
Solar Magnetic Tracking. I. Software Comparison and Recommended Practices
Lamb, D. A.; DeForest, C. E.; Hagenaar, H. J. +2 more
Feature tracking and recognition are increasingly common tools for data analysis, but are typically implemented on an ad hoc basis by individual research groups, limiting the usefulness of derived results when selection effects and algorithmic differences are not controlled. Specific results that are affected include the solar magnetic turnover ti…
AEGIS: Enhancement of Dust-enshrouded Star Formation in Close Galaxy Pairs and Merging Galaxies up to z ~ 1
Weiner, Benjamin J.; Conselice, Christopher J.; Huang, J. -S. +13 more
Using data from the DEEP2 Galaxy Redshift Survey and HST/ACS imaging in the Extended Groth Strip, we select nearly 100 interacting galaxy systems, including kinematic close pairs and morphologically identified merging galaxies. Spitzer MIPS 24 µm fluxes of these systems reflect the current dusty star formation activity, and at a fixed stella…
A TRACE White Light and RHESSI Hard X-Ray Study of Flare Energetics
Fletcher, L.; Hannah, I. G.; Hudson, H. S. +1 more
In this paper we investigate the formation of the white-light (WL) continuum during solar flares and its relationship to energy deposition by electron beams inferred from hard X-ray emission. We analyze nine flares spanning GOES classifications from C4.8 to M9.1, seven of which show clear cospatial RHESSI hard X-ray and TRACE WL footpoints. We cha…
GRB 060505: A Possible Short-Duration Gamma-Ray Burst in a Star-forming Region at a Redshift of 0.09
Sharon, K.; Cenko, S. B.; Price, P. A. +26 more
On 2006 May 5, a 4 s duration, low-energy, ~1049 erg, gamma-ray burst (GRB) was observed, spatially associated with a z=0.0894 galaxy. Here we report the discovery of the GRB optical afterglow and observations of its environment using Gemini South, the Hubble Space Telescope (HST), Chandra, Swift, and the Very Large Array. The optical a…