Automated ACS Bias and Dark Reference File Production, and Improved Detector Trend Analysis (2009)
A. M. Koekemoer, P. Goudfrooij, L. L. Dressel, Ray A. Lucas, Mike Swam, Max Mutchler, ...
Abstract. In the past two years, the production of ACS bias and dark calibration reference files has become almost completely automated. Building upon some code and lessons learned from the automated...
Empirical PSFs and Distortion in the WFC Camera (2009)
A. M. Koekemoer, P. Goudfrooij, L. L. Dressel, Jay Anderson
Abstract. This report summarizes two upcoming ISRs, one on empirical models of the WFC PSF and the other on the distortion solution. Before we can come up with an accurate distortion solution, we...
Recent Developments of the ACS Spectral Extraction Software aXe (2009)
A. M. Koekemoer, P. Goudfrooij, L. L. Dressel, Jeremy R. Walsh, Martin Kümmel, Søren S. Larsen
Abstract. The software package aXe provides comprehensive spectral extraction facilities for all the slitless modes of the ACS, covering the Wide Field Channel (WFC) grism, the High Resolution...
STIS Calibration Enhancement: Wavelength Calibration and CTI (2009)
A. M. Koekemoer, P. Goudfrooij, L. L. Dressel, P. Bristow, F. Kerber, M. Rosa
Abstract. The Instrument Physical Modeling Group in the Space Telescope European Co-ordinating Facility has undertaken to examine aspects of STIS calibration and develop physical model based...
Characterization of Pt/Cr-Ne Hollow-Cathode Lamps for Wavelength Standards in Space Astronomy (2009)
A. M. Koekemoer, P. Goudfrooij, L. L. Dressel, Gillian Nave, Joseph Reader, Craig J. Sansonetti, ...
cathode calibration lamps as used onboard the Hubble Space Telescope (HST). The project has two main components: First, we have observed the spectra of Pt/Cr-Ne lamps to obtain wavelengths for all...
ACS Charge Transfer Efficiency. Results from Internal and External Tests (2009)
A. M. Koekemoer, P. Goudfrooij, L. L. Dressel, M. Chiaberge, A. Riess, M. Mutchler, ...
Abstract. We present results of in-flight charge transfer efficiency (CTE) monitoring performed with different tests. Internal tests (Extended Pixel Edge Response [EPER] and First Pixel Response...
ACS Flat Field Update and New SBC L-flats (2009)
A. M. Koekemoer, P. Goudfrooij, L. L. Dressel, J. Mack, R. C. Bohlin, R. L. Gillil, ...
Abstract. We present an overview of the methods used to create the flat fields which are currently in use by the ACS calibration pipeline. L-flats for the SBC detector have recently been computed...
Memorandum of Understanding between NASA and ESA for the Hubble Space Telescope (2009)
A. M. Koekemoer, P. Goudfrooij, L. L. Dressel, Florian Kerber, Paul Bristow, Michael R. Rosa
the STIS calibration enhancement (STIS-CE) effort as part of the extension of the
NICMOS Temperature Monitoring (2009)
A. M. Koekemoer, P. Goudfrooij, L. L. Dressel, T. Wiklind, T. Wheeler
Abstract. The NICMOS detectors are sensitive to the operating temperature. During the Cycle 7 era, NICMOS was cooled through cryogenic solid nitrogen. This resulted in an operating temperature...
Towards a Comprehensive Sensitivity Calibration of the STIS Echelle Modes (2009)
A. M. Koekemoer, P. Goudfrooij, L. L. Dressel, Alessandra Aloisi
Abstract. I will present the state of the art of the final sensitivity calibration of the STIS spectroscopic echelle modes. This includes 1) the derivation of a new absolute sensitivity for all...
The New GSC-II and its Use for HST (2009)
A. M. Koekemoer, P. Goudfrooij, L. L. Dressel, B. Mclean
Abstract. The second generation HST Guide Star Catalog (GSC-II) provides a significant improvement over the original GSC-I. It provides ICRS-based positions (International Celestial Reference System)...
WFPC2 Status and Calibration (2009)
A. M. Koekemoer, P. Goudfrooij, L. L. Dressel, J. Biretta
Abstract. We briefly summarize the status of WFPC2 as of late 2005, and review calibration results from the last few years. 1.
WFC3 Calibration and Data Processing (2009)
A. M. Koekemoer, P. Goudfrooij, L. L. Dressel, H. Bushouse, S. Baggett, T. Brown, ...
Wide Field Camera 3 (WFC3), a panchromatic imager being developed for the Hubble Space Telescope (HST), is now fully integrated and over the past year has completed first rounds of extensive ground...
Geometric Distortions for the HST MAMA Detectors: STIS NUV-MAMA + FUV-MAMA and ACS SBC (2009)
A. M. Koekemoer, P. Goudfrooij, L. L. Dressel, J. Maíz Apellániz, Maíz Apellániz
Abstract. I present the current status of the geometric distortions for the imaging modes of the three current HST MAMA detectors. A solution for the STIS NUV-MAMA with a typical accuracy of 10 mas...
The 2005 HST Calibration Workshop (2009)
A. M. Koekemoer, P. Goudfrooij, L. L. Dressel, E. A. Barker, A. M. Koekemoer, V. Laidler
Abstract. A general concern with NICMOS images is the issue of “persistence”, or residual charge from bright sources and cosmic rays that remains trapped in pixels and is gradually released...
The 2005 HST Calibration Workshop (2009)
A. M. Koekemoer, P. Goudfrooij, L. L. Dressel, E. Nelan
Abstract. The Fine Guidance Sensor 1R on board HST is used by observers as a science instrument for state of the art relative astrometry and for the high angular resolution of close binary systems....
The 2005 HST Calibration Workshop Space Telescope Science Institute, 2005 (2009)
A. M. Koekemoer, P. Goudfrooij, L. L. Dressel, Paul Goudfrooij, Ralph C. Bohlin, Jesús Maíz-apellániz
Abstract. We review the on-orbit spectroscopic observations that are being used to characterize the Charge Transfer Efficiency (CTE) of the STIS CCD in spectroscopic mode. We parametrize the...
A. M. Koekemoer, P. Goudfrooij, L. L. Dressel, K. Sembach, M. Sirianni, S. Arribas, ...
Abstract. The Hubble Space Telescope is now operating with an attitude control system that relies upon inputs from two mechanical gas bearing gyroscopes and the Fine Guidance Sensors to provide fine...
Modeling and Correcting the Time-Dependent ACS PSF (2009)
A. M. Koekemoer, P. Goudfrooij, L. L. Dressel, Jason Rhodes, Richard Massey, Justin Albert, ...
Abstract. The ability to accurately measure the shapes of faint objects in images taken with the Advanced Camera for Surveys (ACS) on the Hubble Space Telescope (HST) depends upon detailed knowledge...
Hot Pixels Growth in ACS CCDs (2009)
A. M. Koekemoer, P. Goudfrooij, L. L. Dressel, M. Sirianni, M. Mutchler, R. Lucas
Abstract. We present an analysis of the hot pixel population in ACS CCDs. The number of hot pixels increases due to on-orbit radiation damage. In order to heal the defects responsible for the hot...
The HST/STIS Next Generation Spectral Library (2009)
A. M. Koekemoer, P. Goudfrooij, L. L. Dressel, M. D. Gregg, D. Silva, J. Rayner, ...
G750L spectra of 378 bright stars covering a wide range in abundance, effective temperature, and luminosity. This HST/STIS Next Generation Spectral Library was scheduled to reach its goal of 600...
Improving the Absolute Astrometry of HST Data with GSC-II (2009)
A. M. Koekemoer, P. Goudfrooij, L. L. Dressel, A. M. Koekemoer, B. Mclean, M. Mcmaster, ...
Abstract. We have used the new GSC-II to significantly improve the absolute astrometric accuracy of a large number of ACS datasets from the first years of ACS operations, reducing the initial levels...
Calibration and Interpretation of STIS Imaging Mode Fluxes (2009)
A. M. Koekemoer, P. Goudfrooij, L. L. Dressel, Charles R. Proffitt
Abstract. While primarily a spectroscopic instrument, STIS also had a number of imaging modes, many of which provided unique capabilities. However, most of the STIS imaging modes also had very wide...
The Optical Field Angle Distortion Calibration of HST Fine Guidance Sensors 1R and 3 (2009)
A. M. Koekemoer, P. Goudfrooij, L. L. Dressel, B. Mcarthur, G. F. Benedict, W. H. Jefferys, ...
Abstract. To date five OFAD (Optical Field Angle Distortion) calibrations have been performed with a star field in M35, four on FGS3 and one on FGS1, all analyzed by the Astrometry Science Team. We...
Spectral Extraction of Extended Sources Using Wavelet Interpolation (2009)
A. M. Koekemoer, P. Goudfrooij, L. L. Dressel, Paul Barrett, Linda L. Dressel
Abstract. Spatially-resolved spectroscopic investigations of extended sources using STIS, such as galactic black hole mass measurements and chemistry in spatially resolved structures around Eta...
Spectroscopic Point Spread Functions for Centered and Offset Targets (2009)
A. M. Koekemoer, P. Goudfrooij, L. L. Dressel, Linda Dressel
Abstract. Finely sampled observational spectroscopic point spread functions (PSFs) have been generated from exposures of stars. Lyot stops near the pupil plane of the STIS G430L and G750L gratings...
A. M. Koekemoer, P. Goudfrooij, L. L. Dressel, Santiago Arribas, Elizabeth Barker, ...
Abstract. We provide an overview of the most important calibration aspects of the NICMOS instrument on board of HST. We describe the performance of the instrument after the installation of the NICMOS...
HST Temporal Optical Behavior: Models and Measurements with (2009)
A. M. Koekemoer, P. Goudfrooij, L. L. Dressel, R. B. Makidon, M. Lallo
Abstract. While HST provides a stable stellar image relative to ground-based observatories, it features its own characteristic changes in the PSF it delivers to the Science Instruments (Lallo et al....
Slitless Spectroscopy with the Advanced Camera for Surveys (2009)
A. M. Koekemoer, P. Goudfrooij, L. L. Dressel, M. Kümmel, S. S. Larsen, J. R. Walsh
Abstract. The Advanced Camera for Surveys (ACS) enables slitless, low-resolution spectroscopic imaging in its three channels. The most-used modes are grism imaging with the WFC and the HRC at a...
Improving the Rectification of Spectral Images (2009)
A. M. Koekemoer, P. Goudfrooij, L. L. Dressel, Linda Dressel, Paul Barrett, Paul Goudfrooij, ...
Abstract. Single rows in STIS rectified spectral images are being analyzed in science programs where the highest obtainable spatial resolution is needed. Here we discuss two problems that have...
The 2005 HST Calibration Workshop Space Telescope Science Institute, 2005 (2009)
A. M. Koekemoer, P. Goudfrooij, L. L. Dressel, Santiago Arribas, L. Eddie Bergeron, Roelof De Jong, ...
and 12 (regular) calibration programs executed after the installation of the NICMOS Cooling System (NCS). The special calibrations on Cycle 13 were focussed on a follow up of the spectroscopic...
The STIS NUV-MAMA Objective Prism and Looking Beyond for HST UV Slitless Spectroscopy (2009)
A. M. Koekemoer, P. Goudfrooij, L. L. Dressel, J. Maíz Apellániz
Abstract. I discuss the recently implemented absolute flux calibration for the STIS objective prism, which yields fluxes accurate to 1 % rms in the 1300-3000 ˚A range relative to the fluxes measured...
The 2005 HST Calibration Workshop (2009)
A. M. Koekemoer, P. Goudfrooij, L. L. Dressel, James E. Rhoads
in the next decade. Optimum science return on JWST will require high quality calibration. The Hubble Space Telescope offers unique capabilities that will be essential in achieving such a calibration...
Multidrizzle and Tweakshifts: Overview and Future Plans (2009)
A. M. Koekemoer, P. Goudfrooij, L. L. Dressel, A. M. Koekemoer, A. S. Fruchter, R. N. Hook, ...
Abstract. The MultiDrizzle software provides a flexible, unified interface to the various steps involved in registering, cleaning and combining dithered HST data. MultiDrizzle can be run on ACS,...
NICMOS Calibration Challenges in the Ultra Deep Field (2009)
A. M. Koekemoer, P. Goudfrooij, L. L. Dressel, Rodger I. Thompson
Abstract. The reduction of NICMOS observations in the Hubble Ultra Deep Field required unique reduction and calibration techniques, not required for images containing brighter sources. This paper...
Band-limited Imaging with Undersampled Detectors (2009)
A. M. Koekemoer, P. Goudfrooij, L. L. Dressel, Andrew S. Fruchter
Abstract. Over the past decade “Drizzle ” has become a de facto standard for the combination of HST images. However, the drizzle algorithm was developed with small, faint, partially-resolved...
The 2005 HST Calibration Workshop Space Telescope Science Institute, 2005 (2009)
A. M. Koekemoer, P. Goudfrooij, L. L. Dressel, Ronald L. Gilliland
Abstract. Transiting extrasolar planets present an opportunity for probing atmospheric conditions and constituents by taking advantage of different apparent radii, hence transit depth as a function...
A Recalibration of Optical Photometry Based on STIS Spectrophotometry (2009)
A. M. Koekemoer, P. Goudfrooij, L. L. Dressel, J. Maíz Apellániz
Abstract. I use STIS spectrophotometry to test the published sensitivity curves P(λ) and calculate the zero points ZPP for three optical photometry systems: Tycho-2 BTVT, Strömgren uvby, and...
The 2005 HST Calibration Workshop (2009)
A. M. Koekemoer, P. Goudfrooij, L. L. Dressel, A Critical, Test Nicmos Photometry, Bahram Mobasher, ...
Abstract. We compared photometry for the same sources as measured by NIC-MOS and ground-based ISAAC detectors over a large dynamic range. Over a range of magnitudes from 8- 25, we find a linear...
Calibration Status of the Advanced Camera for Surveys (2009)
A. M. Koekemoer, P. Goudfrooij, L. L. Dressel, K. Sembach
Abstract. The Advanced Camera for Surveys is producing spectacular science results that require careful instrument calibration. This article provides an overview of recent calibration highlights and...
Improvements to the STIS First Order Spectroscopic Point Source Flux Calibration (2009)
A. M. Koekemoer, P. Goudfrooij, L. L. Dressel, Charles R. Proffitt
Abstract. During the operational lifetime of STIS, the primary emphasis of throughput measurements was the accurate determination of broad band point source fluxes observed using the low dispersion...
Calibration of the ACS Emission-Line Filters (2009)
A. M. Koekemoer, P. Goudfrooij, L. L. Dressel, C. R. O’dell
Abstract. On-orbit calibration of the ACS emission-line filters F502N, F658N, and F660N have been made using a bright portion of the Orion Nebula as a reference source. This calibration is important...
Calibration of ACS Prism Slitless Spectroscopy Modes (2009)
A. M. Koekemoer, P. Goudfrooij, L. L. Dressel, S. S. Larsen, M. Kümmel, J. R. Walsh
Abstract. The Advanced Camera for Surveys is equipped with three prisms in the Solar Blind (SBC) and High Resolution (HRC) Channels, which together cover the 1150 – 3500 ˚A range, albeit at highly...
The Two-Gyro Pointing Stability of HST, Measured with ACS (2009)
A. M. Koekemoer, P. Goudfrooij, L. L. Dressel, A. M. Koekemoer, V. Kozhurina-platais, M. Sirianni, ...
Abstract. 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 and the validation tests performed...
The 2005 HST Calibration Workshop (2009)
A. M. Koekemoer, P. Goudfrooij, L. L. Dressel, John C. Martin, Kris Davidson
listed in the Acknowledgments Abstract. The HST Eta Carinae Treasury Project made extensive use of the HST/STIS from 1998 to the time of its failure in 2004. As one of the most prolific users of that...
Selection and Characterization of Interesting Grism Spectra (2009)
A. M. Koekemoer, P. Goudfrooij, L. L. Dressel, Gerhardt R. Meurer
Abstract. Observations with the ACS Wide Field Camera and G800L grism can produce thousands of spectra within a single WFC field producing a potentially rich treasure trove of information. However,...
Some Neglected Pixel Problems (2009)
A. M. Koekemoer, P. Goudfrooij, L. L. Dressel, Kris Davidson
Abstract. We have developed several improved techniques because standard reduction software was inadequate for the Treasury Project on η Carinae. Though adapted specifically to HST/STIS/CCD data,...
A. M. Koekemoer, P. Goudfrooij, L. L. Dressel, Paul Goudfrooij, Ra Aloisi, ...
Abstract. The huge archive of STIS observations constitutes a unique —and arguably the most comprehensive — source of spectroscopy in the UV and spatiallyresolved spectroscopy in the optical...
Calibration Status and Results for Wide Field Camera 3 (2009)
A. M. Koekemoer, P. Goudfrooij, L. L. Dressel, Randy A. Kimble
Abstract. Wide Field Camera 3 (WFC3) is a general-purpose imager in development for installation in HST Servicing Mission 4 (SM4). Covering the wavelength range of 200-1700 nm in two observing...
Improving the Spectral Resolution of HST Spectra via LSF Replacement (2009)
A. M. Koekemoer, P. Goudfrooij, L. L. Dressel, Steven V. Penton
Abstract. Large aperture spectra provide greater signal, but small aperture spectra have higher resolution (smaller line-spread function (LSF) wings). The simple method presented here can convert...
A. M. Koekemoer, P. Goudfrooij, L. L. Dressel, Max Mutchler, Marco Sirianni, Ray A. Lucas
Abstract. Our strategies for collecting ACS calibration data, and converting it into reference files for use in the calibration pipeline, have been continually evolving since the instrument was...
QSO Coronagraphy and Ramp Imaging in the ACS GTO Programs (2009)
A. M. Koekemoer, P. Goudfrooij, L. L. Dressel, A. R. Martel, H. C. Ford, G. D. Illingworth, ...
Abstract. We briefly discuss the processing and reduction steps of imaging data acquired in two minor modes of ACS as part of the ACS GTO programs: HRC coronagraphy of the luminous quasar 3C 273 and...
The HST/ACS Coma Cluster Survey: V - Compact Stellar Systems in the Coma Cluster (2009)
Price, J., Phillipps, S., Huxor, A., Trentham, N., Ferguson, H. C., Marzke, R. O., ...
The HST ACS Coma Cluster Treasury Survey is a deep two passband imaging survey of the nearest very rich cluster of galaxies, covering a range of galaxy density environments. The imaging is...
The HST/ACS coma cluster survey – V. Compact stellar systems in the coma cluster (2009)
Price, J., Phillipps, S., Huxor, A., Trentham, N., Ferguson, H. C., Marzke, R. O., ...
The 2005 HST Calibration Workshop (2008)
A. M. Koekemoer, P. Goudfrooij, L. L. Dressel, Polarimetry Nicmos, Dean C. Hines, Glenn Schneider
Abstract. NICMOS cameras 1 and 2 (with ∼ 43 and ∼ 76 mas/pixel, respectively) each carry a set of three polarizing elements to provide high sensitivity observations of linearly polarized light....
Pessev, P. M., Goudfrooij, P., Puzia, T. H., Chandar, R.
We present integrated JHK_s 2MASS photometry and a compilation of integrated-light optical photoelectric measurements for 84 star clusters in the Magellanic Clouds. These clusters range in age from...
Stellar populations across the NGC4244 truncated galactic disk (2007)
De Jong, Roelof S., Seth, A. C., Radburn-Smith, D. J., Bell, E. F., Brown, T. M., Bullock, J. S., ...
We use HST/ACS to study the resolved stellar populations of the nearby, nearly edge-on galaxy NGC4244 across its outer disk surface density break. The stellar photometry allows us to study the...
Maybhate, A., Goudfrooij, P., Schweizer, F., Puzia, T., Carter, D.
We present deep HST ACS images of the post-starburt shell galaxy AM 0139-655. We find evidence for the presence of three distinct globular cluster subpopulations associated with this galaxy: a...
Jablonka, P., Gorgas, J., Goudfrooij, P.
We present the analysis of the radial gradients of stellar absorption lines in a sample of 32 bulges of edge-on spiral galaxies, spanning nearly the full Hubble sequence (from S0 to Sc types), and a...
Stellar Population Gradients in Bulges along the Hubble Sequence: I. The Data (2007)
Gorgas, J., Jablonka, P., Goudfrooij, P.
This is the first paper presenting our long-term project aimed at studying the nature of bulges through the analysis of their stellar population gradients. We present deep spectroscopic observations...
GHOSTS: The Resolved Stellar Outskirts of Massive Disk Galaxies (2007)
De Jong, Roelof S., Seth, A. C., Bell, E. F., Brown, T. M., Bullock, J. S., Courteau, S., ...
We show initial results from our ongoing HST GHOSTS survey of the resolved stellar envelopes of 14 nearby, massive disk galaxies. In hierarchical galaxy formation the stellar halos and thick disks of...
Towards a calibration of SSP models from the optical to the mid-infrared (2007)
Pessev, P., Goudfrooij, P., Puzia, T., Chandar, R.
Our knowledge about unresolved stellar systems comes from comparing integrated-light properties to SSP models. Therefore it is crucial to calibrate the latter as well as possible by integrated-light...
Stellar populations across the NGC 4244 truncated galactic disk (2007)
De Jong, Roelof S., Seth, A. C., Radburn-Smith, D. J., Bell, E. F., Brown, T. M., Bullock, J. S., ...
We use the Hubble Space Telescope ACS to study the resolved stellar populations of the nearby, nearly edge-on galaxy NGC 4244 across its outer disk surface density break. The stellar photometry...
GHOSTS: the resolved stellar outskirts of massive disk galaxies (2007)
De Jong, Roelof S., Seth, A. C., Bell, E. F., Brown, T. M., Bullock, J. S., Courteau, S., ...
We show initial results from our ongoing HST GHOSTS survey of the resolved stellar envelopes of 14 nearby, massive disk galaxies. In hierarchical galaxy formation the stellar halos and thick disks of...
Dynamical mass estimates for two luminous star clusters in galactic merger remnants (2006)
Bastian, N., Saglia, R.P., Goudfrooij, P., Kissler-Patig, M., Maraston, C., Schweizer, F., ...
We present high-dispersion spectra of two extremely massive star clusters in galactic merger remnants. One cluster, W30, is located in the ~500 Myr old merger remnant NGC 7252 and has a velocity...
Dynamical mass estimates for two luminous star clusters in galactic merger remnants (2006)
Bastian, N., Saglia, R. P., Goudfrooij, P., Kissler-Patig, M., Maraston, C., Schweitzer, F., ...
Dynamical Mass Estimates for Two Luminous Star Clusters in Galactic Merger Remnants (2005)
Bastian, N., Saglia, R. P., Goudfrooij, P., Kissler-Patig, M., Maraston, C., Schweizer, F., ...
We present high-dispersion spectra of two extremely massive star clusters in galactic merger remnants. One cluster, W30, is located in the ~500 Myr old merger remnant NGC 7252 and has a velocity...
Grillmair, C., Kissler-Patig, M., Meylan, G., Brodie, J., Minniti, D., Goudfrooij, P.
We investigate the kinematics of a combined sample of 74 globular clusters around NGC 1399.
The Discovery of New Galaxy Members in the NGC 5044 and NGC 1052 Groups (2004)
McKay, N. P. F., Mundell, C. G., Brough, S., Forbes, D. A., Barnes, D. G., James, P. A., ...
We present the results of neutral hydrogen (HI) observations of the NGC 5044 and NGC 1052 groups, as part of a GEMS (Group Evolution Multiwavelength Study) investigation into the formation and...
Maraston, C., Bastian, N., Saglia, R.P., Kissler-Patig, M., Schweizer, F., Goudfrooij, P.
We have determined the dynamical mass of the most luminous stellar cluster known to date, i.e. object W3 in the merger remnant galaxy NGC 7252. The dynamical mass is estimated from the velocity...
VLT spectroscopy of globular cluster systems. I. the photometric and spectroscopic data set (2004)
Puzia, T. H., Kissler-Patig, M., Thomas, D., Maraston, C., Saglia, R. P., Bender, R., ...
Maraston, C., Bastian, N., Saglia, R. P., Kissler-Patig, M., Schweizer, F., Goudfrooij, P.
We have determined the dynamical mass of the most luminous stellar cluster known to date, i.e. object W3 in the merger remnant galaxy NGC 7252. The dynamical mass is estimated from the velocity...
The Chemistry of Extragalactic Globular Clusters (2002)
Kissler-Patig, M., Puzia, T. H., Bender, R., Goudfrooij, P., Hempel, M., Maraston, C., ...
We present preliminary results of VLT/FORS spectroscopy of globular clusters in nearby early-type galaxies. Our project aims at studying the chemistry and determine the ages of globular cluster...
Extragalactic Globular Clusters in the Near-Infrared (2002)
Hempel, M., Kissler-Patig, M., Hilker, M., Puzia, T. H., Brodie, J. P., Goudfrooij, P., ...
Visual and near-infrared colours are used to identify intermediate-age globular cluster in early-type galaxies. In NGC5846 and NGC4365 colour-colour diagrams (V-I vs. V-K) reveal a sub-population in...
Stellar Populations in Bulges of Spiral Galaxies (2002)
Jablonka, P., Gorgas, J., Goudfrooij, P.
We have conducted a spectroscopic analysis of the bulges of a sample of 31 spiral galaxies, spanning the Hubble sequence from S0 to Scd type, in order to study the radial distribution of their...
Rejkuba, M., Minniti, D., Gregg, M. D., Zijlstra, A. A., Alonso, M. V., Goudfrooij, P.
We have obtained V and I-band photometry for 1886 stars down to I=27 and V=28 in the field of the dwarf irregular galaxy WLM, using deep STIS CL and LP-band images taken in the parallel mode with the...
ISO far-infrared observations of rich galaxy clusters II. Sersic 159-03 (2000)
Hansen, L., Jorgensen, H. E., Norgaard-Nielsen, H. U., Pedersen, K., Goudfrooij, P.
The far-infrared emission from rich galaxy clusters is investigated. Maps have been obtained by ISO at 60, 100, 135, and 200 microns using the PHT-C camera. Ground based imaging and spectroscopy were...
Line Strengths and Line Strength Gradients in Bulges along the Hubble Sequence (1999)
Goudfrooij, P., Gorgas, J., Jablonka, P.
We present first results of a comprehensive survey of deep long-slit spectra along the minor axis of bulges of edge-on spiral galaxies. Our results indicate that stellar populations in bulges are...
The fading optical counterpart of GRB 970228, 6 months and 1 year later (1999)
Fruchter, A.S., Pian, E., Thorsett, S.E., Bergeron, L.E., Gonzalez, R.A., Metzger, M.R., ...
Panel Discussion: Star Formation in Early-Type Galaxies. (1999)
Knapp, G.R., Binette, L., Bower, R., Brinks, E., Goudfrooij, P., Hau, G., ...
The Fading Optical Counterpart of GRB~970228, Six Months and One Year Later (1998)
Fruchter, A. S., Pian, E., Thorsett, S. E., Bergeron, L. E., Gonzalez, R. A., Metzger, M., ...
We report on observations of the fading optical counterpart of the gamma-ray burst GRB 970228, made with the Hubble Space Telescope STIS CCD approximately six months after outburst and with the...
Massive stars running through space (1997)
Kaper, L., Loon, J.TH. Van, Augusteijn, T., Goudfrooij, P., Patat, F., ...
Discovery of a bow shock around Vela X-1 (1997)
Kaper, L., Loon, J.Th. Van, Augusteijn, T., Goudfrooij, P., Patat, F., ...
Globular Clusters in the Inner Regions of NGC5128 (Cen A) (1996)
Minniti, D., Alonso, M. V., Goudfrooij, P., Jablonka, P., Meylan, G.
We have identified 26 new globular cluster candidates in the inner 3 kpc of NGC 5128 (Cen A), the nearest known large galaxy being the probable product of a merger. The clusters are selected on the...