P. Goudfrooij - Academia.edu (original) (raw)

Papers by P. Goudfrooij

Research paper thumbnail of Calibration and Interpretation of STIS Imaging Mode Fluxes

Abstract. While primarily a spectroscopic instrument, STIS also had a number of imaging modes, ma... more 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 and non-standard passbands, making calibration and interpretation of STIS imaging data especially challenging. Here we describe the methods used to derive the adopted throughput curves, zero points, and aperture corrections for these modes. The wide, non-standard passbands of STIS imaging modes also present special challenges when comparing with observations in other photometric systems. We discuss the relationship between STIS magnitudes and colors and those of other common photometric systems. 1. STIS Imaging Throughput Time Dependence and Zero Points. The STIS instrument has three detectors, a CCD sensitive from ∼ 2000 to 10300 ˚A, a Cs2Te Multi-Anode Microchannel Array (MAMA) detector (1600 to 3100 ˚A) and a solarblind CsI MAMA (1150 to 1700 ˚A). Sensitivities of these detectors have varied over time. For a given detector these changes depend on wavelength, but appear to be independent of the mode. So for imaging observations we adopt the same time dependence vs. wavelength that was determined for the first order spectroscopic modes by Stys et al. (2004). This leads to considerable color dependence of the sensitivity changes with time. In Figure 1 we give examples of the predicted sensitivity changes for stars of different colors at 380 day intervals over the 7+ year operational life of STIS. Figure 1: Predicted changes in sensitivity as a function of time and color for selected STIS modes are shown at 380 day intervals over the operational lifetime of the STIS instrument. The available detector/imaging filter combinations are summarized in Table 1 for a time near the beginning of STIS operations. In this table PHOTPLAM is the pivot wavelength 1

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Research paper thumbnail of The ACS Solar Blind Channel calibration

Abstract. The ACS MAMA detector, also known as the Solar Blind Channel (SBC) is currently HST’s p... more Abstract. The ACS MAMA detector, also known as the Solar Blind Channel (SBC) is currently HST’s principal detector in the far UV. Since the loss of STIS, more attention is now being paid to SBC calibration. New dark images have been supplied and the flat fields formerly measured on the ground have been refined. The prism modes have also been recently calibrated and an improved distortion correction is being prepared. 1. Description The ACS Solar Blind Channel (SBC) is a spare STIS MAMA operating in the far-UV from 1150 to 1700 ˚A. It contains a CsI photocathode deposited directly on a curved microchannel plate. Electrons generated by photons striking the photocathode enter the microchannel plate which sends an amplified electron cloud onto a multi-anode plate configured so that the incident position can be decoded. The SBC has high resolution (pixel size of 0.03 arcsec) and sensitivity plus extremely low dark current ( ∼ < 10 −5 counts per pixel). The performance and principal ca...

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Research paper thumbnail of Pipeline Calibrations

Abstract. Our strategies for collecting ACS calibration data, and converting it into reference fi... more 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 installed during Hubble Servicing Mission 3B in March of 2002. We provide an historical overview of basic ACS pipeline calibrations, including the impact that some of the more recent changes have on downstream data processing (e.g. drizzling). This paper emphasizes bias and dark calibrations for the ACS CCDs, and it represents a significant update to previous documentation of this subject (Mutchler et al. 2004). We describe the expected detector degradations that these calibrations are designed to track and correct, and also some unexpected anomalies we’ve encountered and the steps we’ve taken to ameliorate them.

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Research paper thumbnail of VizieR Online Data Catalog: Extinction and star Clusters in NGC 1275 (Norgaard-Nielsen+ 1993)

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Research paper thumbnail of Norgaard-Nielsen H.U., Goudfrooij P., Jorgensen H.E., Hansen

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Research paper thumbnail of The Galactic foreground reddening of SN 1987 A

Astronomy and Astrophysics

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Research paper thumbnail of On the nature of AFGL 2477

Astronomy and Astrophysics

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Research paper thumbnail of Where Will PyRAF Lead Us? The Future of Data Analysis Software at STScI

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Research paper thumbnail of Warm IRAS sources. II-Optical spectroscopy of objects from the point source catalog

Astronomy and …, 1992

ASTRONOMY & ASTROPHYSICS SUPPLEMENT SERIES DECEMBER I 1992, PAGE 389 Astron. Astrophys. Suppi. Se... more ASTRONOMY & ASTROPHYSICS SUPPLEMENT SERIES DECEMBER I 1992, PAGE 389 Astron. Astrophys. Suppi. Ser. 96, 389-428 (1992) Warm IRAS sources. II. Optical spectroscopy of objects from the point source catalog* MHK de Grijp', WC Keel"2, GK Miley', P. ...

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Research paper thumbnail of ISO far-infrared observations of rich galaxy clusters II. Sersic 159-03

arXiv (Cornell University), Feb 22, 2000

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Research paper thumbnail of Globulars in PGC 6510, PGC 10922, PGC 4287

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Research paper thumbnail of The 2005 HST Calibration Workshop Space Telescope Science Institute, 2005

and 12 (regular) calibration programs executed after the installation of the NICMOS Cooling Syste... more 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 recalibration initiated in Cycle 12. This program led to the discovery of a possible count rate non-linearity, which has triggered a special program for Cycle 13 and a number of subsequent tests and calibrations during Cycle 14. At the time of writing this is a very active area of research. We also briefly comment on other calibrations defined to address other specific issues like: the autoreset test, the SPARS sequence tests, and the low-frequency flat residuals for NIC1. The calibration programs for the 2-Gyro campaigns are not included here, since they have been described elsewhere (see Sembach et al. 2006, in these proceedings). Further details and updates on specific programs can be found via the NICMOS web site. 1.

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Research paper thumbnail of Luminosity profiles and sizes of massive star clusters in

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Research paper thumbnail of ASTRONOMY AND ASTROPHYSICS ISO far-infrared observations of rich galaxy clusters ⋆

A&A manuscript no. (will be inserted by hand later) Your thesaurus codes are:

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Research paper thumbnail of Formation channels of slowly rotating early-type galaxies

Astronomy & Astrophysics, 2020

We study the evidence for a diversity of formation processes in early-type galaxies by presenting... more We study the evidence for a diversity of formation processes in early-type galaxies by presenting the first complete volume-limited sample of slow rotators with both integral-field kinematics from the ATLAS3D Project and high spatial resolution photometry from the Hubble Space Telescope. Analysing the nuclear surface brightness profiles of 12 newly imaged slow rotators, we classify their light profiles as core-less, and place an upper limit to the core size of about 10 pc. Considering the full magnitude and volume-limited ATLAS3D sample, we correlate the presence or lack of cores with stellar kinematics, including the proxy for the stellar angular momentum (λRe) and the velocity dispersion within one half-light radius (σe), stellar mass, stellar age, α-element abundance, and age and metallicity gradients. More than half of the slow rotators have core-less light profiles, and they are all less massive than 1011 M⊙. Core-less slow rotators show evidence for counter-rotating flattened ...

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Research paper thumbnail of Multiple populations in globular clusters and their parent galaxies

Monthly Notices of the Royal Astronomical Society, 2019

The ‘chromosome map’ diagram (ChM) proved a successful tool to identify and characterize multiple... more The ‘chromosome map’ diagram (ChM) proved a successful tool to identify and characterize multiple populations (MPs) in 59 Galactic globular clusters (GCs). Here, we construct ChMs for 11 GCs of both Magellanic Clouds (MCs) and with different ages to compare MPs in Galactic and extragalactic environments, and explore whether this phenomenon is universal through ‘place’ and ‘time’. MPs are detected in five clusters. The fractions of 1G stars, ranging from ∼50 per cent to >80 per cent, are significantly higher than those observed in Galactic GCs with similar present-day masses. By considering both Galactic and MC clusters, the fraction of 1G stars exhibits: (i) a strong anticorrelation with the present-day mass, and (ii) with the present-day mass of 2G stars; (iii) a mild anticorrelation with 1G present-day mass. All Galactic clusters without MPs have initial masses smaller than ∼1.5 · 105 M⊙ but a mass threshold governing the occurrence of MPs seems challenged by massive simple-pop...

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Research paper thumbnail of Interstellar matter in elliptical galaxies - III. Properties of dust extinction

Monthly Notices of the Royal Astronomical Society, 1994

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Research paper thumbnail of Discovery of a Bow Shock around Vela X-1

The Astrophysical Journal, 1997

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Research paper thumbnail of Line Strengths and Line Strength Gradients in Bulges Along the Hubble Sequence

Toward a New Millennium in Galaxy Morphology, 2000

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Research paper thumbnail of VizieR Online Data Catalog: Coma Treasury Survey. Structural parameters (Hoyos+, 2011)

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Research paper thumbnail of Calibration and Interpretation of STIS Imaging Mode Fluxes

Abstract. While primarily a spectroscopic instrument, STIS also had a number of imaging modes, ma... more 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 and non-standard passbands, making calibration and interpretation of STIS imaging data especially challenging. Here we describe the methods used to derive the adopted throughput curves, zero points, and aperture corrections for these modes. The wide, non-standard passbands of STIS imaging modes also present special challenges when comparing with observations in other photometric systems. We discuss the relationship between STIS magnitudes and colors and those of other common photometric systems. 1. STIS Imaging Throughput Time Dependence and Zero Points. The STIS instrument has three detectors, a CCD sensitive from ∼ 2000 to 10300 ˚A, a Cs2Te Multi-Anode Microchannel Array (MAMA) detector (1600 to 3100 ˚A) and a solarblind CsI MAMA (1150 to 1700 ˚A). Sensitivities of these detectors have varied over time. For a given detector these changes depend on wavelength, but appear to be independent of the mode. So for imaging observations we adopt the same time dependence vs. wavelength that was determined for the first order spectroscopic modes by Stys et al. (2004). This leads to considerable color dependence of the sensitivity changes with time. In Figure 1 we give examples of the predicted sensitivity changes for stars of different colors at 380 day intervals over the 7+ year operational life of STIS. Figure 1: Predicted changes in sensitivity as a function of time and color for selected STIS modes are shown at 380 day intervals over the operational lifetime of the STIS instrument. The available detector/imaging filter combinations are summarized in Table 1 for a time near the beginning of STIS operations. In this table PHOTPLAM is the pivot wavelength 1

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Research paper thumbnail of The ACS Solar Blind Channel calibration

Abstract. The ACS MAMA detector, also known as the Solar Blind Channel (SBC) is currently HST’s p... more Abstract. The ACS MAMA detector, also known as the Solar Blind Channel (SBC) is currently HST’s principal detector in the far UV. Since the loss of STIS, more attention is now being paid to SBC calibration. New dark images have been supplied and the flat fields formerly measured on the ground have been refined. The prism modes have also been recently calibrated and an improved distortion correction is being prepared. 1. Description The ACS Solar Blind Channel (SBC) is a spare STIS MAMA operating in the far-UV from 1150 to 1700 ˚A. It contains a CsI photocathode deposited directly on a curved microchannel plate. Electrons generated by photons striking the photocathode enter the microchannel plate which sends an amplified electron cloud onto a multi-anode plate configured so that the incident position can be decoded. The SBC has high resolution (pixel size of 0.03 arcsec) and sensitivity plus extremely low dark current ( ∼ < 10 −5 counts per pixel). The performance and principal ca...

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Research paper thumbnail of Pipeline Calibrations

Abstract. Our strategies for collecting ACS calibration data, and converting it into reference fi... more 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 installed during Hubble Servicing Mission 3B in March of 2002. We provide an historical overview of basic ACS pipeline calibrations, including the impact that some of the more recent changes have on downstream data processing (e.g. drizzling). This paper emphasizes bias and dark calibrations for the ACS CCDs, and it represents a significant update to previous documentation of this subject (Mutchler et al. 2004). We describe the expected detector degradations that these calibrations are designed to track and correct, and also some unexpected anomalies we’ve encountered and the steps we’ve taken to ameliorate them.

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Research paper thumbnail of VizieR Online Data Catalog: Extinction and star Clusters in NGC 1275 (Norgaard-Nielsen+ 1993)

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Research paper thumbnail of Norgaard-Nielsen H.U., Goudfrooij P., Jorgensen H.E., Hansen

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Research paper thumbnail of The Galactic foreground reddening of SN 1987 A

Astronomy and Astrophysics

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Research paper thumbnail of On the nature of AFGL 2477

Astronomy and Astrophysics

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Research paper thumbnail of Where Will PyRAF Lead Us? The Future of Data Analysis Software at STScI

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Research paper thumbnail of Warm IRAS sources. II-Optical spectroscopy of objects from the point source catalog

Astronomy and …, 1992

ASTRONOMY & ASTROPHYSICS SUPPLEMENT SERIES DECEMBER I 1992, PAGE 389 Astron. Astrophys. Suppi. Se... more ASTRONOMY & ASTROPHYSICS SUPPLEMENT SERIES DECEMBER I 1992, PAGE 389 Astron. Astrophys. Suppi. Ser. 96, 389-428 (1992) Warm IRAS sources. II. Optical spectroscopy of objects from the point source catalog* MHK de Grijp', WC Keel"2, GK Miley', P. ...

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Research paper thumbnail of ISO far-infrared observations of rich galaxy clusters II. Sersic 159-03

arXiv (Cornell University), Feb 22, 2000

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Research paper thumbnail of Globulars in PGC 6510, PGC 10922, PGC 4287

Bookmarks Related papers MentionsView impact

Research paper thumbnail of The 2005 HST Calibration Workshop Space Telescope Science Institute, 2005

and 12 (regular) calibration programs executed after the installation of the NICMOS Cooling Syste... more 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 recalibration initiated in Cycle 12. This program led to the discovery of a possible count rate non-linearity, which has triggered a special program for Cycle 13 and a number of subsequent tests and calibrations during Cycle 14. At the time of writing this is a very active area of research. We also briefly comment on other calibrations defined to address other specific issues like: the autoreset test, the SPARS sequence tests, and the low-frequency flat residuals for NIC1. The calibration programs for the 2-Gyro campaigns are not included here, since they have been described elsewhere (see Sembach et al. 2006, in these proceedings). Further details and updates on specific programs can be found via the NICMOS web site. 1.

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Research paper thumbnail of Luminosity profiles and sizes of massive star clusters in

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Research paper thumbnail of ASTRONOMY AND ASTROPHYSICS ISO far-infrared observations of rich galaxy clusters ⋆

A&A manuscript no. (will be inserted by hand later) Your thesaurus codes are:

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Research paper thumbnail of Formation channels of slowly rotating early-type galaxies

Astronomy & Astrophysics, 2020

We study the evidence for a diversity of formation processes in early-type galaxies by presenting... more We study the evidence for a diversity of formation processes in early-type galaxies by presenting the first complete volume-limited sample of slow rotators with both integral-field kinematics from the ATLAS3D Project and high spatial resolution photometry from the Hubble Space Telescope. Analysing the nuclear surface brightness profiles of 12 newly imaged slow rotators, we classify their light profiles as core-less, and place an upper limit to the core size of about 10 pc. Considering the full magnitude and volume-limited ATLAS3D sample, we correlate the presence or lack of cores with stellar kinematics, including the proxy for the stellar angular momentum (λRe) and the velocity dispersion within one half-light radius (σe), stellar mass, stellar age, α-element abundance, and age and metallicity gradients. More than half of the slow rotators have core-less light profiles, and they are all less massive than 1011 M⊙. Core-less slow rotators show evidence for counter-rotating flattened ...

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Research paper thumbnail of Multiple populations in globular clusters and their parent galaxies

Monthly Notices of the Royal Astronomical Society, 2019

The ‘chromosome map’ diagram (ChM) proved a successful tool to identify and characterize multiple... more The ‘chromosome map’ diagram (ChM) proved a successful tool to identify and characterize multiple populations (MPs) in 59 Galactic globular clusters (GCs). Here, we construct ChMs for 11 GCs of both Magellanic Clouds (MCs) and with different ages to compare MPs in Galactic and extragalactic environments, and explore whether this phenomenon is universal through ‘place’ and ‘time’. MPs are detected in five clusters. The fractions of 1G stars, ranging from ∼50 per cent to >80 per cent, are significantly higher than those observed in Galactic GCs with similar present-day masses. By considering both Galactic and MC clusters, the fraction of 1G stars exhibits: (i) a strong anticorrelation with the present-day mass, and (ii) with the present-day mass of 2G stars; (iii) a mild anticorrelation with 1G present-day mass. All Galactic clusters without MPs have initial masses smaller than ∼1.5 · 105 M⊙ but a mass threshold governing the occurrence of MPs seems challenged by massive simple-pop...

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Research paper thumbnail of Interstellar matter in elliptical galaxies - III. Properties of dust extinction

Monthly Notices of the Royal Astronomical Society, 1994

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Research paper thumbnail of Discovery of a Bow Shock around Vela X-1

The Astrophysical Journal, 1997

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Research paper thumbnail of Line Strengths and Line Strength Gradients in Bulges Along the Hubble Sequence

Toward a New Millennium in Galaxy Morphology, 2000

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Research paper thumbnail of VizieR Online Data Catalog: Coma Treasury Survey. Structural parameters (Hoyos+, 2011)

Bookmarks Related papers MentionsView impact