Related papers: WFC3/UVIS: External CTE Monitoring 2009-2024
In this report, we examine the behavior of Charge Transfer Efficiency (CTE) on the WFC3/UVIS detector over time as computed by the Extended Pixel Edge Response (EPER) technique, using internal calibration data acquired from 2009 through…
Using repeat imaging of a galaxy cluster taken over a seventeen-year baseline, we examine the impact that degraded Charge Transfer Efficiency (CTE) has on photometric measurements of extended sources using the ACS/WFC on HST. We examine how…
Most discussion of charge-transfer-efficiency (CTE) losses involves the parallel transfer of charge in the y-direction down the chip columns (y-CTE). Serial charge-transfer efficiency (x-CTE) refers to the horizontal transer of charge.…
A variety of on-orbit imaging and spectroscopic observations are used to characterize the Charge Transfer Efficiency (CTE) of the Charge-Coupled Device (CCD) of the Space Telescope Imaging Spectrograph (STIS) aboard the Hubble Space…
Charge-transfer loss on the Wide Field Planetary Camera 2 (WFPC2) onboard the Hubble Space Telescope is a primary source of uncertainty in stellar photometry obtained with this camera. This effect, discovered shortly after the camera was…
We use an empirical approach to characterize the effect of charge-transfer efficiency (CTE) losses in images taken with the Wide-Field Channel of the Advanced Camera for Surveys. The study is based on profiles of warm pixels in 168 dark…
We present an overview of a 90-orbit Hubble Space Telescope treasury program to obtain near ultraviolet imaging of the Hubble Ultra Deep Field using the Wide Field Camera 3 UVIS detector with the F225W, F275W, and F336W filters. This survey…
We present a dedicated study of CCD serial ($x$-direction) charge transfer efficiency (CTE) in ACS/WFC. Following past studies of parallel ($y$-direction) CTE, we use the serial CTE trails behind hot pixels in calibration dark frames to…
The calwf3 software for WFC3/UVIS utilizes a reference file to flag pixels that are saturated beyond their full-well depth. Previously, this was accomplished using a constant threshold of 65,500 e$^{-}$ across the entire detector. In this…
We update a physically-motivated model of radiation damage in the Hubble Space Telescope Advanced Camera for Surveys/Wide Field Channel, using data up to mid 2010. We find that Charge Transfer Inefficiency increased dramatically before…
We have used 23 years of Hubble Space Telescope ACS/SBC data to study what background levels are encountered in practice and how much they vary. The backgrounds vary considerably, with F115LP, F122M, F125LP, PR110L, and PR130L all showing…
Charge-transfer effects in photometry with Wide Field Planetary Camera 2 aboard the Hubble Space Telescope are investigated by a comparison of WFPC2 observations with groundbased photometry for the Galactic globular clusters omega Centauri…
Charge-Coupled Device (CCD) detectors, widely used to obtain digital imaging, can be damaged by high energy radiation. Degraded images appear blurred, because of an effect known as Charge Transfer Inefficiency (CTI), which trails bright…
(Abridged) We present the first detections of the mean flux of the optical extragalactic background light (EBL) at 3000, 5500, and 8000A. Diffuse foreground flux at these wavelengths comes from terrestrial airglow, dust-scattered sunlight…
A new determination of WFPC2 photometric corrections is presented, using HSTphot reduction of the WFPC2 Omega Centauri and NGC 2419 observations from January 1994 through March 2000 and a comparison with ground-based photometry. No evidence…
In crowded fields, small-aperture photometry can reduce contamination errors from neighboring sources compared to larger aperture photometry. However, the UVIS encircled energy (EE) varies with detector position and focus variations on…
Charge Transfer Inefficiency (CTI) due to radiation damage above the Earth's atmosphere creates spurious trailing in Hubble Space Telescope (HST) images. Radiation damage also creates unrelated warm pixels - but these happen to be perfect…
We align more than 7,400 WFC3/UVIS exposures to the Gaia DR3 catalog to examine the time evolution of the linear terms (shift, rotation, scale and skew) of the geometric distortion solution between 2009 and 2022. We find small linear…
From 2002 to 2025, the Hubble Space Telescope's Advanced Camera for Surveys has suffered in the harsh radiation environment above the protection of the Earth's atmosphere. We track the degradation of its image quality, as Solar protons and…
HST/WFC3's spatial scan monitor automatically reduces and analyzes time-series data taken in spatial scan mode with the IR grisms. Here we describe the spatial scan monitor pipeline and present results derived from eight years of transiting…