We have developed a method to measure the counts in cosmic ray tails (CRTs) which result frim imperfect charge transfer efficiency (CTE). Like previous measures of CTE, the counts in the CRTs are a...
ACS Coronagraph Performance in Two-Gyro Mode, Instrument Science Report ACS (2009)
In February 2005, as part of a study of HST performance using two gyroscopes instead of three, the ACS coronagraph was exercised in two-gyro mode and its quality compared with that in the normal...
Instrument Science Report WFPC2 2008-02 Evolution of WFPC2 (2008)
Deepashri Thatte, John Biretta
We examine the evolution of the WFPC2 superbiases from 1996 to 2007. Relatively little change is seen, implying generally good stability of the readout electronics during the 14+ years of WFPC2...
Optical polarimetry of the jets of nearby radio galaxies: I. The Data (2006)
Perlman, Eric, Padgett, Alex, Georganopoulos, Markos, Sparks, William, Biretta, John, O'Dea, Christopher, ...
Archived in: arXiv:astro-ph/0606119 v1 6 Jun 2006
Optical polarimetry of the jets of nearby radio galaxies: I. The data (2006)
Perlman, Eric, Padgett, Alex, Georganopoulos, Markos, Sparks, William, Biretta, John, O'Dea, Christopher, ...
Archived in: arXiv:astro-ph/0606119 v1 6 Jun 2006
Instrument Science Report ACS 2005-07 Two-Gyro Pointing Stability of HST measured with ACS (2005)
Anton M. Koekemoer, Vera Kozhurina-platais, Adam Riess, John Biretta, Cheryl Pavlovsky
We present the results of the pointing stability tests for HST, as measured with the ACS/ HRC during the Two-Gyro test program conducted in February 2005. We measure the shifts of 185 exposures of...
Instrument Science Report WFPC2 2002-04 An Analysis of WFPC2 Filter Positional Anomalies (2002)
Shireen Gonzaga, Sylvia Baggett, John Biretta
In March of 2001, a routine analysis of FR533N VISFLAT images revealed an anomaly: the filter wheel appeared to be offset by about 0.42 ° in some images. This offset angle is close to 0.5° degrees,...
Anton M. Koekemoer, John Biretta, Jennifer Mack
We present updated flatfields for WFPC2 using on-orbit data from Earthflat exposures, covering dates ranging from September 1995- May 2001. We divide the flatfields into epochs depending on the...
Optical Structure and Physics of the M87 Jet (2001)
Perlman, Eric, Sparks, William, Biretta, John, Macchetto, Duccio, Leahy, J. Patrick
We summarize HST observations of the M87 jet, concentrating on polarimetry and spectral index maps, and compare its optical and radio structures. The evidence now supports a stratified model for the...
WFPC2 Flatfields with Reduced Noise (2001)
Erich Karkoschka, John Biretta
We examine the noise contributed by the WFPC2 flatfields during normal calibration, and provide new low-noise flats for 41 filters. Highly exposed science images (>20,000 electrons per pixel) will...
Preliminary Assessment of the FR533N Filter Anomaly (2001)
Shireen Gonzaga, Sylvia Baggett, John Biretta
Analysis of FR533N VISFLAT images has revealed an apparently randomly-occurring rotational offset of about 0.5 degrees in some images, a quantity that corresponds to one filter step. The pivot point...
The Optical-Near-IR Spectrum of the M87 Jet From HST Observations (2000)
Perlman, Eric S., Biretta, John, Sparks, William, Macchetto, Duccio, Leahy, J. Patrick
We present 1998 HST observations of M87 which yield the first single-epoch optical and radio-optical spectral index images of the jet at $0.15''$ resolution. We find $ \approx 0.67$, comparable to...
Face-on dust disks in galaxies with optical jets (2000)
Sparks, William, Baum, Stefi, Biretta, John, Macchetto, Ferdinando, Martel, Andre
Also archived in: arXiv: astro-ph/0007358 v1 24 Jul 2000
Face-on dust disks in galaxies with optical jets (2000)
Sparks, William, Baum, Stefi, Biretta, John, Macchetto, Ferdinando, Martel, Andre
Also archived in: arXiv: astro-ph/0007358 v1 24 Jul 2000
Face-on Dust Disks in Galaxies with Optical Jets (2000)
Sparks, William B., Baum, Stefi A., Biretta, John, Macchetto, F. Duccio, Martel, Andre' R.
The presence of optical synchrotron jets in radio galaxies is relatively rare. Here, we show that of the nearest five FR-I 3CR radio galaxies showing optical jets, {\it four} show evidence for almost...
Results of the WFPC2 Observatory Verification after Servicing Mission 3a (2000)
Shireen Gonzaga, Sylvia Baggett, Jesus Balleza, John Biretta, Inge Heyer, Anton M. Koekemoer, ...
After six weeks of inactivity, the Servicing Mission 3a, and the tests and observations carried out as part of the ensuing Observatory Verification phase, WFPC2 restarted science operations on...
Hubble Space Telescope snapshot survey of 3CR quasars: the data (1999)
Lehnert, Matthew, Miley, George, Sparks, William, Baum, Stefi, Biretta, John, Golombek, Daniel, ...
Also archived in: arXiv :astro-ph/9904106 v1 8 Apr 1999
Hubble Space Telescope snapshot survey of 3CR quasars: The Data (1999)
Lehnert, Matthew, Miley, George, Sparks, William, Baum, Stefi, Biretta, John, Golombek, Daniel, ...
Also archived in: arXiv :astro-ph/9904106 v1 8 Apr 1999
HST Snapshot Survey of 3CR Quasars: The Data (1999)
Lehnert, Matthew D., Miley, George K., Sparks, William B., Baum, Stefi A., Biretta, John, Golombek, Daniel, ...
We present images taken with the Wide Field Planetary Camera (WFPC-2) on the Hubble Space Telescope of 43 quasars selected from the 3CR radio catalog. The redshift range of the targets is large ---...
Sylvia Baggett, John Biretta, Shireen Gonzaga, Inge Heyer, Matt Mcmaster
The drizzle software combines dithered images while preserving photometric accuracy, enhancing resolution, and removing geometric distortion. A recent upgrade also allows removal of cosmic rays from...
Charge Trapping and CTE Residual Images in the WFPC2 CCDs (1998)
We have studied the charge trapping problem in the WFPC2 CCDs by examining residual images in dark calibration exposures taken at various intervals after non-saturated planetary exposures. Charge is...