Search Publications
Principal Component Analysis of the Time- and Position-dependent Point-Spread Function of the Advanced Camera for Surveys
Ford, H. C.; Jee, M. J.; Blakeslee, J. P. +3 more
We describe the time- and position-dependent point-spread function (PSF) variation of the wide-field channel (WFC) of the Advanced Camera for Surveys (ACS) with the principal component analysis (PCA) technique. The time-dependent change is caused by the temporal variation of the HST focus, whereas the position-dependent PSF variation in ACS WFC at…
Hubble Space Telescope Advanced Camera for Surveys Mosaic of the Prototypical Starburst Galaxy M82
Gallagher, J. S.; Bond, H. E.; Noll, K. S. +9 more
In 2006 March, the Hubble Heritage Team obtained a large, four-filter (B, V, I, and Hα), 6 point mosaic data set of the prototypical starburst galaxy NGC 3034 (M82) with the Advanced Camera for Surveys on board the Hubble Space Telescope (HST). The resulting color composite Heritage image was released in 2006 April to celebrate HST's 16th annivers…
Near-Ultraviolet Spectra of Flares on YZ CMi
Hawley, Suzanne L.; Valenti, Jeff A.; Walkowicz, Lucianne M. +1 more
Near-ultraviolet spectroscopic data obtained with the Hubble Space Telescope STIS (Space Telescope Imaging Spectrograph) instrument on the dMe flare star YZ Canis Minoris (YZ CMi) were analyzed. Flare and quiet intervals were identified from the broadband near-UV light curve, and the spectrum of each flare was separately extracted. Mg II and Fe II…
A Hubble Space Telescope Survey of the Disk Cluster Population of M31. I. WFPC2 Pointings
Hodge, P. W.; Krienke, O. K.
As a follow-up to the automated cluster search carried out by Williams & Hodge, we have examined 39 Hubble Space Telescope Wide Field Planetary Camera 2 (WFPC2) pointings to locate and study a comprehensive collection of disk clusters. The Williams technique was effective in finding young clusters, but not intermediate-age or old clusters. Our…
Saturn's Rings at True Opposition
French, Richard G.; Dones, Luke; Salo, Heikki +2 more
On 2005 January 14, the Saturn system was observed at true opposition with the planetary camera of the Wide Field Planetary Camera 2 (WFPC2) on the Hubble Space Telescope. This was the culmination of nearly a decade of similar UBVRI observations, yielding a uniform set of over 400 high spatial resolution and photometrically accurate radial profile…
The Distribution of Activity on the RS CVn-Type Star SZ Piscium
Henry, Gregory W.; Eaton, Joel A.
We use contemporaneous spectra and BV light curves to derive a model of the distribution of spots and active regions on the cooler component of SZ Psc for the 1993-1994 season. For that epoch, both spots and active regions were visible at all rotational phases of this chromospherically active star. The lack of large distortions of Doppler profiles…
Interstellar Absorption-Line Evidence for High-Velocity Expanding Structures in the Carina Nebula Foreground
Walborn, Nolan R.; Smith, Nathan; Gull, Theodore R. +3 more
The extreme, high-velocity interstellar absorption-line profiles toward η Carinae and 16 neighboring stars in Trumpler 16 are examined, including several new sight lines observed in the ultraviolet with the Hubble Space Telescope or in the optical from the Magellan and European Southern Observatories. No two sight lines are identical, but many vel…
Measuring the Balmer Jump and the Effective Gravity in FGK Stars
Bessell, Michael S.
It is difficult to accurately measure the effective gravity (logg) in late-type stars using broadband (e.g., UBV or SDSS) or intermediate-band (uvby) photometric systems, especially when the stars can cover a range of metallicities and reddenings. However, simple spectroscopic observational and data reduction techniques can yield accurate values f…
SIM PlanetQuest Key Project Precursor Observations to Detect Gas Giant Planets around Young Stars
Metchev, Stanimir; Prato, L.; Herbst, William +10 more
We present a review of precursor observing programs for the SIM PlanetQuest Key Project devoted to detecting Jupiter-mass planets around young stars. In order to ensure that the stars in the sample are free of various sources of astrometric noise that might impede the detection of planets, we have initiated programs to collect photometry, high-con…
Jitter Correction Algorithms for the COROT Satellite Mission: Validation with Test Bench Data and MOST On-Orbit Photometry
Auvergne, M.; Drummond, R.; Aerts, C. +5 more
We demonstrate the effectiveness and robustness of photometric correction algorithms for satellite pointing jitter in the upcoming space mission COROT, which will study asteroseismology and search for exoplanets. Two algorithms based on model-based estimation and decorrelation are tested in two ways: (1) with artificial light sources in the COROT …