Study of the evolution of the ACS/WFC sensitivity loss

Size: px
Start display at page:

Download "Study of the evolution of the ACS/WFC sensitivity loss"

Transcription

1 Instrument Science Report ACS Study of the evolution of the ACS/WFC sensitivity loss Leonardo Úbeda and Jay Anderson Space Telescope Science Institute January 28, 2013 ABSTRACT We present a study of the sensitivity loss of the ACS/WFC CCDs for one medium-band, eight broad-band, and three narrow-band filters. This study was done using a calibration field located 6.7 arcmin West of the center of globular cluster 47 Tucanae. For pre-sm4 images, a comparison of the sensitivity loss rates found in this research with those calculated using standard white dwarf stars by Bohlin, R. et al. (ISR ACS ) shows excellent agreement within the uncertainties of the two methods. We found that the sensitivity losses are less than mag/year. We also have a baseline of at least three years of post-sm4 observations of the 47 Tucanae calibration field. Our study shows that, on average, the sensitivity loss post- SM4 is negligible. This is a remarkable result considering that ACS is an instrument that has been in space for over ten years and subject to contamination. 1. Introduction The Advanced Camera for Surveys (ACS) Wide Field Camera (WFC) consists of two charge-coupled devices (CCDs), which are butted together along their long dimension to create an effective array. The spectral sensitivity of the WFC ranges from 3500Å Copyright c 2013 The Association of Universities for Research in Astronomy, Inc. All Rights Reserved. 1

2 to 11000Å. As part of the yearly calibration program, ACS/WFC observations are taken regularly of flux standard stars and star cluster fields to monitor the photometric performance of the camera and its filters. In this Instrument Science Report (ISR) we intend to quantify the photometric change by analyzing ten years of observations of a particular calibration field in the outskirts of globular cluster 47 Tucanae. We explore here the entire current database of ACS observations in a wide range of filters, using both science programs and special calibration proposals. According to Bohlin, R. et al. (ISR ACS ) two important events in the life of ACS have introduced discontinuities in the sensitivity evolution. The first event took place on 04 July 2006 and it is the decrease in the ACS operating temperature from 77 C to 81 C in order to lower the number of observed hot pixels. The second event is the CCD Electronics Box Replacement (CEB-R) that took place during Servicing Mission 4 (SM4) in May 2009 in an effort to remedy the ACS failure in January To account for these changes, we follow the recommendation of ISR ACS and separate analyses for time periods before and after the ACS failure were performed. In this ISR we report the results of our photometric study of the sensitivity of the ACS/WFC using 47 Tucanae data and compare them to the sensitivity loss rates presented in ISR ACS using observations of white dwarf standard stars G191B2B, GD153, and GD71. We also present new measurements of the WFC CCDs sensitivity loss using post-sm4 images. For a complete study of the ACS High Resolution Channel (HRC) please refer to Bohlin, R. et al. (ISR ACS ). Their study shows no obvious differences for the loss rates between WFC and HRC. 2. Observations The main calibration field for this study is located about 6.7 arcmin West of the center of globular cluster 47 Tucanae. This calibration field has been observed multiple times through many ACS/WFC filters for both calibration and science purposes. We downloaded the entire database of ACS observations from MAST in the following filters: F435W, F475W, F502N, F550M, F555W, F606W, F625W, F658N, F660N, F775W, F814W, and F850LP. The sensitivity of the cameras should be independent of the integration time for each exposure; however, the longer exposures provide much better signal to noise for more stars, so we focus here on the deeper exposures whenever possible All images with integration time shorter than 30 seconds were not included in this study. Some of the images in the Archive were not successful. These include several images from HST proposal 9018 (PI: G. de Marchi) which show all stars as streaks and were not suitable for this study. Most images from proposal (PI: M. Sirianni) were also discarded. The main goal of proposal was to test the ACS/WFC operating at three different tempertatures: 74 C, 77 C, and 80 C. For this study we only 2

3 kept the images obtained at an operating temperature of 77 C. The automated calibration pipeline CALACS (version 8.0.6, 18 Jul 2012) takes care of the basic data reduction (bias, dark, flat field corrections). We downloaded the flat fielded images (_FLT files), as well as the CTE corrected images (_FLC files). The _FLC files are data products generated using the pixel based CTE correction algorithm (PixelCTE v3.2; Anderson & Bedin, 2010). Figure 1 shows the ACS/WFC footprints for all the F606W images that were used (exposure time > 300 sec). The background is an STScI Digitized Sky Survey image depicting the center of globular cluster 47 Tucanae and its Western field. The footprints are organized according to year of observation and shown in red. In Table 1 we list the number of F606W images used for this study (second column) organized by year of observation, as an example. The third column lists the proposal identification numbers from the STScI observing programs. The fourth column gives the total integration time (in units of seconds) for all deep observations. Year Images Proposal IDs Exposure Time (count) (seconds) Table 1: F606W observations used in this study. Shown as an example. 3. Method 3.1 Aperture Photometry The main goal of this project was to compare accurately measured photometry of as many stars as possible (> 1000 stars) in a given field in different epochs and determine whether there is a trend that shows some kind of sensitivity loss. Our analysis is statistical in nature. 3

4 Figure 1: ACS/WFC footprints for the F606W images with exposure time > 300 seconds used for the calculation of the sensitivity loss. The background is an STScI Digitized Sky Survey image depicting the center of globular cluster 47 Tucanae and its Western field. North is up and East is left. The footprints are organized according to year of observation and shown in red. The orange outline represents the location of the sources in the F606W master initial catalog. To acomplish this task, positions and fluxes of point sources were accurately measured with the software img2xym_wfc.09x10 in the FORTRAN library of codes by J. Anderson. This code includes the best available geometric distortion solution and is documented and described in detail in Anderson, J. & King, I. (ISR ACS ). This calibration field is not excessively crowded which means that aperture photometry should suffice for our purpose. Aperture pho- 4

5 tometry was performed on all _FLT and _FLC files for all filters. This task produces an _xym file for each exposure containing the position and magnitude for each found source. Since astrometry is not critical here, the positions are measured with simple centroids. The fluxes are measured using an aperture of 3.5 pixels and a sky between 8 and 12 pixels. The positions are corrected for geometric distortion and the fluxes are corrected for pixel area and converted into instrumental magnitudes ( 2.5 log(flux)) where the flux is given in units of electrons. See Section 4.2 for comments on changes in the PSF encircled energy due to variations in the telescope focus. In July 2006, the temperature of the WFC detector was lowered from 77 C to 81 C in order to mitigate the impact of transfer inefficiencies and the production of hot pixels. This temperature change caused a loss in sensitivity (Mack, J. et al. ISR ACS ) which we took into account for all the observations made after the temperature change. 3.2 Initial Master Catalogs ACS was installed on board HST in March 2002 during SM3B (ACS Instrument Handbook; Úbeda, L. et al. 2012). This initial epoch is the baseline against which we measure sensitivity loss. For each filter we built photometric catalogs by combining the magnitude measurements of a set of images from these original observations. For most filters, observations from program 9018 provide a wide spatial coverage and enough well-measured stars to create the initial epoch catalogs. In most cases, images from April and May 2002 were used. For narrow band filters there were no observations available from program 9018 and images from programs 9656 (PI: G. de Marchi) and/or 9663 (PI: R. Gilliland) were used instead. Unfortunately, several F606W images from proposal 9018 failed (stars show as short streaks) and therefore, images from proposals 9433 (PI: G. Bernstein), 9648 (PI: A. Riess), and 9656 had to be considered. This means that the initial catalog for F606W consists of the combination of measurements obtained from April 2002 until March To cross-identify the stars in each exposure with the master list, we used an in-house FORTRAN program from Anderson, J. & King, I. (ISR ACS ). These cross-identified stars define a linear transformation from the distortion-corrected frame of each exposure into the master frame. We then used a different in-house program to generate a master list of stars that could be found in a minimum number of exposures through each filter. Table 2 shows the number of sources found in each initial master catalog as a function of filter. Column three lists the proposal identification numbers for the observations used and column four shows the range of observation dates assumed as initial epoch. The orange outline in Figure 1 represents the location of the stars in the F606W initial master catalog as an example. 5

6 Filter Sources (count) Proposal IDs Date Range F850LP April 2002 F814W April 2002 May 2002 F775W April 2002 October 2002 F660N July 2002 July 2003 F658N October 2002 August 2003 F625W April 2002 December 2002 F606W April 2002 March 2003 F555W May 2002 F550M July 2002 July 2003 F502N September 2002 August 2003 F475W October 2002 August 2003 F435W May 2002 Table 2: Summary of the initial master catalogs. The number of stars in each catalog are listed as well as the range of observation dates assumed as initial epoch. Whenever possible, images from GO program 9018 were used. 3.3 Position/Magnitude Correlation. The Relative Photometry Once we had the master catalog of stars for each filter, we went back and cross-identified the stars in the individual exposures. We included only those stars that were bright but not saturated by selecting sources with flux (in units of electrons) such that 13.0 < 2.5 log(flux) < 9.0 or 4000 flux electrons. Although fluxes for saturated stars can be measured reliably using approaches described in Gilliland, R. L. (ISR ACS ), we focus here on the unsaturated stars, since bleeding can take flux out of our apertures. The _xym files contain many false detections, such as cosmic rays, hot pixels, or features around saturated stars. These detections are weeded out by our cross-identification procedure. 4. Results For each exposure, the cross-identification procedure above gives us a list of stars with photometry in the exposure and average photometry from the master list. Figure 2 shows an example of our typical magnitude residuals for 1300 matched stars from F775W image j8hm01yrq_flt.fits observed on 16 March 2003 and the F775W initial master catalog. This plot clearly shows a larger dispersion for fainter objects as expected. The adopted mean value was calculated using an iteratively sigma clipping flux weighted method. We used σ = 2.0 to reject possible bad outliers clearly seen in Figure 2. The final mean value is shown as a red horizontal line. The dotted lines represent the adopted error in the calculated average. This 6

7 average magnitude difference ( m) gives us the information that we need to measure whether a sensitivity trend exists or not. We analyze the average magnitude difference ( m) as a function of time for each filter. Since observations have different exposure times, we scaled the averages to an exposure time of 1000 seconds. We also shifted the plots so that m = 0.0 at the time of the installation of the ACS on board HST (07 March 2002) during Servicing Mission 3B. Figure 3 shows the results for broad-band filters F814W, F775W, F625W, and F606W. Figure 4 shows the results for broad-band filters F555W, F475W, and F435W and for medium-band filter F550M. Figure 5 shows the results for narrow-band filters F660N, F658N, and F502N, and for wide filter F850LP. Figure 2: Typical magnitude residual plot before scaling for exposure time. It shows the difference in magnitude of 1300 matched stars from F775W image j8hm01yrq_flt.fits (m) and the F775W initial master catalog (m cat ). The horizontal axis represents the average of the two magnitudes. The horizontal red line represents the adopted average. Each plot shows the average magnitude difference ( m) as a function of time in units of years. The plots on the left were created with the _FLT files as input. The plots on the right were created with the _FLC files as input. A dashed line through m = 0.0 is displayed to aid the eye. The symbols are represented in two shades of blue: the light blue symbols represent short exposure observations (exposure time lower that 300 seconds); the dark blue symbols represent long exposures (exposure time > 300 seconds). All plots span the lifetime of ACS/WFC: from March 2002 until the present, through failure in January 2007 and successful restoration during Servicing Mission 4 (SM4) in May Because of the electronics change in May 2009 the time period before and after the ACS failure must be analyzed separately (ISR ACS ). 4.1 Analysis and Discussion of pre-sm4 data Sensitivity changes of pre-sm4 data have already been published and presented in ISR ACS Table 1 in that document lists the rate of sensitivity loss in magnitudes per year for all the filters that we analyze in this ISR. The losses are less than mag/year, and were calculated using high precision aperture photometry of three white dwarf primary standard stars, namely G191B2B, GD153, and GD71. Charge transfer inefficiencies have been taken into account in this study using a parameterized CTE correction formula from ISR ACS

8 The left panels of Figures 3, 4, and 5 show the results of the study performed on 47 Tuc _FLT images (no CTE correction applied). The change in sensitivity for each filter is fit with a line shown in red. The orange lines represent the white dwarf fit from ISR ACS The estimated slopes (in units of magnitudes/year) and formal errors are shown in Table 3. The fitting was performed by minimizing the χ 2 error statistic. The error assigned to the point that represents each image is given by 1σ of the distribution. Measurements performed using short exposures (integration time < 300 seconds) are less reliable and, for that reason, their errors were arbitrarily doubled. This method assigns a higher weight to measurements done on long exposures. The right panels of Figures 3, 4, and 5 show the results of the study performed on 47 Tuc _FLC images. These images have been corrected using the pixel-based CTE correction. The estimated slopes (in units of magnitudes/year) and formal errors are shown in Table 3 In general, the 47 Tuc sensitivity loss rates are in agreement with the WD method values within the errors. This is true specially for filters F435W, F475W, F502N, F550M, F625W, F775W, and F814W. Narrow-band filters F658N and F660N show slightly worse sensitivity losses. The study of filter F606W shows a perfect agreement with the WD method if the _FLT files are considered. If the correction for ineffective CTE is taken into account, the 47 Tuc method shows that the sensitivity loss is somewhat smaller. Filter WD Study 47 Tuc Study APPHOT FLT APPHOT FLC epsf FLC F435W (0.0006) (0.0006) F475W (0.0018) (0.0018) F502N (0.0010) (0.0010) F550M (0.0010) (0.0010) F555W (0.0012) (0.0012) F606W (0.0004) (0.0004) (0.0004) F625W (0.0015) (0.0015) F658N (0.0018) (0.0018) F660N (0.0015) (0.0015) F775W (0.0007) (0.0007) (0.0007) F814W (0.0012) (0.0012) (0.0012) F850LP (0.0006) (0.0006) Table 3: Estimated pre-sm4 sensitivity losses per year as a function of ACS/WFC filter for _FLT and _FLC images. The errors are between parentheses. The losses and their errors are expressed in units of magnitudes per year. The values in the second column are taken from ISR ACS These are the values of the fourth order polynomial fit and have a formal error of mag/year. 8

9 Figure 3: Magnitude residuals average as a function of time for filters F814W, F775W, F625W, and F606W. Dark blue symbols correspond to deep observations (exposure time > 300 sec) and short exposures are shown in light blue. The orange line represents the pre-sm4 fitting using the standard white dwarf stars from ISR ACS The red line is the best fit of the 47 Tucanae study. 4.2 Telescope Breathing and Changes in Focus Having selected an aperture radius of 3.5 WFC pixels (0.175) for the aperture photometry means that changes in the PSF encircled energy due to telescope focus variations will be present in our measurements. In order to quantify this effect and verify our method we repeated the study for filters F814W and F775W using epsf photometry (ISR ACS ) with the flag PERT activated. This allows the code to find a spatially constant perturbation to the library of PSFs to account for focus variations that impact the inner 5.0 pixels of the PSF. The final flux 9

10 Figure 4: Magnitude residuals average as a function of time for filters F555W, F550M, F475W, and F435W. Dark blue symbols correspond to deep observations (exposure time > 300 sec) and short exposures are shown in light blue. The orange line represents the pre-sm4 fitting using the standard white dwarf stars from ISR ACS The red line is the best fit of the 47 Tucanae study. is calculated with respect to a 10.0 pixel aperture. Figure 6 shows a comparison between aperture and epsf photometry for filter F814W. All the points correspond to deep exposures (integration time > 300 seconds). It is evident (see bottom panels) that in some cases, observations made on the same day present m variations of up to 0.01 mag. The same measurements made using epsf photometry show lower dispersion becasue the telescope focus variations are taken into account. However, a similar sensitivity loss is found for both methods. The epsf method averages out the focus variations before the linear fitting and the statistical approach presented in this ISR averages out during the χ 2 error 10

11 Figure 5: Magnitude residuals average as a function of time for filters F850LP, F660N, F658N, and F502N. Dark blue symbols correspond to deep observations (exposure time > 300 sec) and short exposures are shown in light blue. The orange line represents the pre-sm4 fitting using the standard white dwarf stars from ISR ACS The red line is the best fit of the 47 Tucanae study. Note that the CTE corrections for narrow-band filters F660N and F658N are large because of the low backgrounds detected in those images. This is specially important for post-sm4 data. statistic fitting. Figure 7 shows an equivalent study for filter F775W. Note that both deep and short exposures were considered for this filter. The lower dispersion in the epsf study is quite evident. The final fitting of the _FLC images shows virtually the same sensitivity loss. In Table 3 we report the values of the sensitivity loss estimated using epsf photometry in three filters. 11

12 Figure 6: Comparison between aperture (bottom) and epsf (top) photometry for images obtained with filter F814W. Figure 7: Comparison between aperture (bottom) and epsf (top) photometry for images obtained with filter F775W. Note that the epsf photometry shows lower dispersion, because this type of photometry accounts for telescope-focus variations. See text for more details. 12

13 4.3 Analysis and Discussion of post-sm4 data During Servicing Mission 4 (SM4) in May 2009 the CCD Electronics Box Replacement (CEB- R) took place and the gain of the new electronics was set so that the measured signal matched the signal for the same 47 Tucanae field as measured in Due to the lack of sufficient data, Bohlin, R. et al. (2011) adopt a slope arbitrarily set to zero for the post-sm4 points in the [ m, time] plane. For most filters we now have at least three years of observations of the calibration field and we are able to quantify the sensitivity of the WFC post-sm4 and provide information on the current status of the CCDs. Filter 47 Tuc Study FLC F435W (0.0005) F475W (0.0006) F502N (0.0003) F550M (0.0004) F555W (0.0005) F606W (0.0001) F625W (0.0008) F658N (0.0006) F660N (0.0004) F775W (0.0005) F814W (0.0003) F850LP (0.0004) Table 4: Estimated sensitivity losses per year as a function of ACS/WFC filter for _FLC post-sm4 data. The errors from the χ 2 error statistic fitting are between parentheses. The losses and their errors are expressed in units of magnitudes per year. We adopt the same initial master catalogs that were used for the pre-sm4 data. Figures 3, 4, and 5 show the results of the study performed on 47 Tuc images. By comparing the left plots (_FLT images) with the plots on the right (_FLC images), a first impression shows the effect of the CTE correction as a function of time. The CTE correction is larger for post-sm4 data than for pre-sm4 data as shown in Úbeda, L. & Anderson, J. (ISR ACS ). With the current study we are able to confirm those results. Moreover, it is very clear that the point distributions post-sm4 are virtually flat for all filters. The change in sensitivity for each filter was fit with a line by minimizing the χ 2 error statistic. The estimated slopes (in units of magnitudes/year) and formal errors are shown in Table 4. These results show that the loss in sensitivity post-sm4 is negligible. 13

14 5 Conclusions We performed a study of the sensitivity loss of the ACS/WFC CCDs using twelve filters. This study was done using a calibration field about 6.7 arcmin West of the center of globular cluster 47 Tucanae. For data obtained before SM4, a comparison of the sensitivity loss rates with those calculated using standard white dwarf stars by Bohlin, et al. (2011) shows excellent agreement within the uncertainties of both methods as can be seen in Figure 8. The only large discrepancy corresponds to filter F606W where our study shows a lower sensitivity loss ( mag/year as opposed to mag/year). The use of epsf photometry leads to the value mag/year. Refer to Table 3. The advantage of the pixel-based CTE correction is clearly seen in Figures 3, 4, and 5. In particular, those plots show the CTE dependency with date of observation as well as exposure time. Our results confirm the study of the CTE evolution in ISR ACS Figure 8: Pre-SM4 slopes in units of magnitudes per year for the twelve filters that were analyzed with the 47 Tucanae data. The fourth order fit from Bohlin, R. et al. (2011) is shown as a black line with the uncertainty shown as dashed lines. Error bars on each point are taken from Table 3. Most of the error bars cross the fit with the exception of F606W. We now have a baseline of at least three years of post-sm4 observations of the 47 Tucanae calibration field. Our study shows that, on average, the magnitude difference ( m) is stable over time. This is a remarkable result considering that ACS is an instrument that has been in space for over ten years and subject to contamination. A future research using the white dwarf standards on a longer time baseline would be able to confirm or improve the loss rates presented in this ISR. No corrections to the observed photometry are necessary because the current PHOTFLAM header keywork in the ACS/WFC images is calculated as a function of time using the formulae provided by Bohlin, R. et al. (2011). 14

15 Acknowledgments The authors would like to thank L. Smith (ACS Lead), R. Bohlin, A. Maybhate, V. Kozhurina- Platais, and M. Chiaberge for their comments and revision suggestions that resulted in substantial improvement of this work. The authors acknowledge J. Mack, P-L. Lim, and R. Avila for their past contributions to this project. References Anderson, J. & Bedin, L. R. 2010, PASP, 122, Anderson, J. & King, I. R., 2006, Instrument Science Report ACS (Baltimore: STScI) Bohlin, R. & Anderson, J. 2011, Instrument Science Report ACS (Baltimore: STScI) Bohlin, R. et al. 2011, Instrument Science Report ACS (Baltimore: STScI) Gilliland, R. L. 2004, Instrument Science Report ACS (Baltimore: STScI) Mack, J. et al. 2007, Instrument Science Report ACS (Baltimore: STScI) Úbeda, L. & Anderson, J. 2012, Instrument Science Report ACS (Baltimore: STScI) Úbeda, L. et al. 2012, ACS Instrument Handbook, Version 12.0 (Baltimore: STScI) 15

The Impact of x-cte in the WFC3/UVIS detector on Astrometry

The Impact of x-cte in the WFC3/UVIS detector on Astrometry Instrument Science Report WFC3 2014-02 The Impact of x-cte in the WFC3/UVIS detector on Astrometry Jay Anderson April 4, 2014 ABSTRACT Recent observations of the center of globular cluster Omega Centauri

More information

WFC3/UVIS and IR Multi-Wavelength Geometric Distortion

WFC3/UVIS and IR Multi-Wavelength Geometric Distortion SPACE TELESCOPE SCIENCE INSTITUTE Operated for NASA by AURA Instrument Science Report WFC 2012-07 WFC3/UVIS and IR Multi-Wavelength Geometric Distortion V. Kozhurina-Platais, M. Dulude, T. Dahlen, C. Cox

More information

ACS after SM4: RELATIVE GAIN VALUES AMONG THE FOUR WFC AMPLIFIERS

ACS after SM4: RELATIVE GAIN VALUES AMONG THE FOUR WFC AMPLIFIERS Instrument Science Report ACS 2009-03 ACS after SM4: RELATIVE GAIN VALUES AMONG THE FOUR WFC AMPLIFIERS R. C. Bohlin, A. Maybhate, & J. Mack 2009 October 8 ABSTRACT For the default setting of gain=2, the

More information

Focus-diverse, empirical PSF models for the ACS/WFC

Focus-diverse, empirical PSF models for the ACS/WFC Instrument Science Report ACS/WFC 2018-08 Focus-diverse, empirical PSF models for the ACS/WFC Andrea Bellini, Jay Anderson, & Norman A. Grogin November 20, 2018 Space Telescope Science Institute, 3700

More information

ACS CCDs UV and narrowband filters red leak check

ACS CCDs UV and narrowband filters red leak check Instrument Science Report ACS 2007-03 ACS CCDs UV and narrowband filters red leak check Marco Chiaberge and Marco Sirianni May 01, 2007 ABSTRACT We present results of the observations of the star 15 Mon,

More information

NICMOS Status and Plans

NICMOS Status and Plans 1997 HST Calibration Workshop Space Telescope Science Institute, 1997 S. Casertano, et al., eds. NICMOS Status and Plans Rodger I. Thompson Steward Observatory, University of Arizona, Tucson, AZ 85721

More information

FLAT FIELDS FROM THE MOONLIT EARTH

FLAT FIELDS FROM THE MOONLIT EARTH Instrument Science Report WFPC2 2008-01 FLAT FIELDS FROM THE MOONLIT EARTH R. C. Bohlin, J. Mack, and J. Biretta 2008 February 4 ABSTRACT The Earth illuminated by light from the full Moon was observed

More information

Calibration of ACS Prism Slitless Spectroscopy Modes

Calibration of ACS Prism Slitless Spectroscopy Modes The 2005 HST Calibration Workshop Space Telescope Science Institute, 2005 A. M. Koekemoer, P. Goudfrooij, and L. L. Dressel, eds. Calibration of ACS Prism Slitless Spectroscopy Modes S. S. Larsen, M. Kümmel

More information

Updated flux calibration and fringe modelling for the ACS/WFC G800L grism

Updated flux calibration and fringe modelling for the ACS/WFC G800L grism Updated flux calibration and fringe modelling for the ACS/WFC G800L grism H. Kuntschner, M. Kümmel, J. R. Walsh January 25, 2008 ABSTRACT A revised flux calibration is presented for the G800L grism with

More information

Time Dependence of ACS WFC CTE Corrections for Photometry and Future Predictions

Time Dependence of ACS WFC CTE Corrections for Photometry and Future Predictions Time Dependence of ACS WFC CTE Corrections for Photometry and Future Predictions Adam Riess, Jennifer Mack May 5, 2004 ABSTRACT We present measurements of photometric losses due to imperfect parallel and

More information

First On-orbit Measurements of the WFC3-IR Count-rate Non-Linearity

First On-orbit Measurements of the WFC3-IR Count-rate Non-Linearity First On-orbit Measurements of the WFC3-IR Count-rate Non-Linearity A. G. Riess March 10, 2010 ABSTRACT Previous HgCdTe detectors on HST have suffered from a count-rate dependent non-linearity, motivating

More information

The Accuracy of WFPC2 Photometric Zeropoints

The Accuracy of WFPC2 Photometric Zeropoints The Accuracy of WFPC2 Photometric Zeropoints Inge Heyer, Marin Richardson, Brad Whitmore, Lori Lubin July 23, 2004 ABSTRACT The accuracy of WFPC2 photometric zeropoints is examined using two methods. The

More information

Extraction of Point Source Spectra from STIS Long Slit Data

Extraction of Point Source Spectra from STIS Long Slit Data 1997 HST Calibration Workshop Space Telescope Science Institute, 1997 S. Casertano, et al., eds. Extraction of Point Source Spectra from STIS Long Slit Data J. R. Walsh Spect Telescope European Coordinating

More information

WFC3 IR Blobs, IR Sky Flats and the measured IR background levels

WFC3 IR Blobs, IR Sky Flats and the measured IR background levels The 2010 STScI Calibration Workshop Space Telescope Science Institute, 2010 Susana Deustua and Cristina Oliveira, eds. WFC3 IR Blobs, IR Sky Flats and the measured IR background levels N. Pirzkal 1 Space

More information

SBC L-Flat Corrections and Time-Dependent Sensitivity

SBC L-Flat Corrections and Time-Dependent Sensitivity SBC L-Flat Corrections and Time-Dependent Sensitivity J. Mack, R. Gilliland, R. van der Marel, and R. Bohlin November 17, 2005 ABSTRACT The uniformity of the SBC detector response has been assessed using

More information

Absolute Flux Calibration for STIS First-Order, Low-Resolution Modes

Absolute Flux Calibration for STIS First-Order, Low-Resolution Modes Instrument Science Report STIS 97-14 Absolute Flux Calibration for STIS First-Order, Low-Resolution Modes Ralph Bohlin, Space Telescope Science Institute Nicholas Collins, Hughes STX/LASP/GSFC Anne Gonnella,

More information

WFC3 Calibration Using Galactic Clusters

WFC3 Calibration Using Galactic Clusters Instrument Science Report WFC3 2009-006 WFC3 Calibration Using Galactic Clusters E. Sabbi, J. Kalirai, A. Martel, S. Deustua, S.M. Baggett, T. Borders, H. Bushouse, M. Dulude, B. Hilbert, J. Kim Quijano,

More information

Astrometric Performance of STIS CCD CTI Corrections on Omega Cen Images

Astrometric Performance of STIS CCD CTI Corrections on Omega Cen Images Instrument Science Report STIS 2015-05 Astrometric Performance of STIS CCD CTI Corrections on Omega Cen Images John Biretta, Sean Lockwood, and John Debes September 28, 2015 ABSTRACT We are in the process

More information

Earth Flats. 1. Introduction. Instrument Science Report ACS R. C. Bohlin, J. Mack, G. Hartig, & M. Sirianni October 25, 2005

Earth Flats. 1. Introduction. Instrument Science Report ACS R. C. Bohlin, J. Mack, G. Hartig, & M. Sirianni October 25, 2005 Instrument Science Report ACS 2005-12 Earth Flats R. C. Bohlin, J. Mack, G. Hartig, & M. Sirianni October 25, 2005 ABSTRACT Since the last ISR 2003-02 on the use of Earth observations for a source of flat

More information

SBC FLATS: PRISM P-FLATS and IMAGING L-FLATS

SBC FLATS: PRISM P-FLATS and IMAGING L-FLATS Instrument Science Report ACS 2006-08 SBC FLATS: PRISM P-FLATS and IMAGING L-FLATS R. C. Bohlin & J. Mack December 2006 ABSTRACT The internal deuterium lamp was used to illuminate the SBC detector through

More information

On-orbit Calibration of ACS CTE Corrections for Photometry

On-orbit Calibration of ACS CTE Corrections for Photometry On-orbit Calibration of ACS CTE Corrections for Photometry Adam Riess August 15, 2003 ABSTRACT We present the first on-orbit calibration of the photometric losses due to imperfect CTE on ACS HRC and WFC.

More information

TECHNICAL REPORT. Doc #: Date: Rev: JWST-STScI , SM-12 August 31, Authors: Karl Gordon, Ralph Bohlin. Phone:

TECHNICAL REPORT. Doc #: Date: Rev: JWST-STScI , SM-12 August 31, Authors: Karl Gordon, Ralph Bohlin. Phone: When there is a discrepancy between the information in this technical report and information in JDox, assume JDox is correct. TECHNICAL REPORT Title: Title: JWST Absolute Flux Calibration II: Expanded

More information

The WFC3 IR Blobs Monitoring

The WFC3 IR Blobs Monitoring The WFC3 IR Blobs Monitoring N. Pirzkal, B. Hilbert Nov 13, 2012 ABSTRACT We present new results on the WFC3 IR Blobs based on analysis of data acquired using the WFC3 IR channel from 2010 to 2012. In

More information

Improved Photometry for G750L

Improved Photometry for G750L SPACE TELESCOPE SCIENCE INSTITUTE Operated for NASA by AURA Instrument Science Report STIS 2015-01(v1) Improved Photometry for G750L R.C. Bohlin 1, C.R. Proffitt 1 1 Space Telescope Science Institute,

More information

The in-orbit wavelength calibration of the WFC G800L grism

The in-orbit wavelength calibration of the WFC G800L grism The in-orbit wavelength calibration of the WFC G800L grism A. Pasquali, N. Pirzkal, J.R. Walsh March 5, 2003 ABSTRACT We present the G800L grism spectra of the Wolf-Rayet stars WR45 and WR96 acquired with

More information

APLUS: A Data Reduction Pipeline for HST/ACS and WFC3 Images

APLUS: A Data Reduction Pipeline for HST/ACS and WFC3 Images APLUS: A Data Reduction Pipeline for HST/ACS and WFC3 Images Wei Zheng 1,AmitSaraff 2,3,LarryBradley 4,DanCoe 4,AlexViana 4 and Sara Ogaz 4 1 Department of Physics and Astronomy, Johns Hopkins University,

More information

Cross-Talk in the ACS WFC Detectors. I: Description of the Effect

Cross-Talk in the ACS WFC Detectors. I: Description of the Effect Cross-Talk in the ACS WFC Detectors. I: Description of the Effect Mauro Giavalisco August 10, 2004 ABSTRACT Images acquired with the Wide Field Channel (WFC) of the Advanced Camera for Surveys (ACS) are

More information

A First Look at Cosmic Rays on ACS

A First Look at Cosmic Rays on ACS A First Look at Cosmic Rays on ACS Adam Riess June 6, 2002 ABSTRACT We have made an initial study of the characteristics of cosmic ray impacts on the two ACS imaging cameras, HRC and WFC. The fraction

More information

Here Be Dragons: Characterization of ACS/WFC Scattered Light Anomalies

Here Be Dragons: Characterization of ACS/WFC Scattered Light Anomalies Instrument Science Report ACS 2016-06 Here Be Dragons: Characterization of ACS/WFC Scattered Light Anomalies Blair Porterfield, Dan Coe, Shireen Gonzaga, Jay Anderson, Norman Grogin November 1, 2016 Abstract

More information

Data Processing in DES

Data Processing in DES Data Processing in DES Brian Yanny Oct 28, 2016 http://data.darkenergysurvey.org/fnalmisc/talk/detrend.p Basic Signal-to-Noise calculation in astronomy: Assuming a perfect atmosphere (fixed PSF of p arcsec

More information

Grism Sensitivities and Apparent Non-Linearity

Grism Sensitivities and Apparent Non-Linearity Instrument Science Report NICMOS 2005-002 Grism Sensitivities and Apparent Non-Linearity Ralph C. Bohlin, Don J. Lindler, & Adam Riess May 10, 2005 ABSTRACT Recent grism observations using the NICMOS instrument

More information

A Study of the Time Variability of the PSF in F606W Images taken with WFC3/UVIS

A Study of the Time Variability of the PSF in F606W Images taken with WFC3/UVIS Instrument Science Report WFC3 2015-08 A Study of the Time Variability of the PSF in F606W Images taken with WFC3/UVIS Jay Anderson, Matthew Bourque, Kailash Sahu, Elena Sabbi, Alex Viana May 28, 2015

More information

Relative Astrometry Within ACS Visits

Relative Astrometry Within ACS Visits Instrument Science Report ACS 2006-005 Relative Astrometry Within ACS Visits Richard L. White August 07, 2006 ABSTRACT The log files from APSIS, the ACS science team s image processing pipeline, have been

More information

Delivery of a new ACS SBC throughput curve for Synphot

Delivery of a new ACS SBC throughput curve for Synphot Delivery of a new ACS SBC throughput curve for Synphot Francesca R. Boffi, M. Sirianni, R. A. Lucas, N. R. Walborn, C. R. Proffitt April 18, 2008 ABSTRACT On November 12th, 2007 a new ACS SBC throughput

More information

arxiv:astro-ph/ v3 7 Apr 2005 Space Telescope Science Institute 2, 3700 San Martin Drive, Baltimore, MD 21218, U.S.A.

arxiv:astro-ph/ v3 7 Apr 2005 Space Telescope Science Institute 2, 3700 San Martin Drive, Baltimore, MD 21218, U.S.A. Accepted at Publications of the Astronomical Society of the Pacific (June 2005 issue) A cross-calibration between Tycho-2 photometry and HST spectrophotometry arxiv:astro-ph/0504085v3 7 Apr 2005 J. Maíz

More information

ACS PSF variations with temperatures

ACS PSF variations with temperatures Instrument Science Report ACS 07-12 ACS PSF variations with temperatures Kailash C. Sahu, Matt Lallo, Russ Makidon September 18, 2007 ABSTRACT We have used the HST ACS/WFC observations of a Galactic bulge

More information

Breathing, Position Drift, and PSF Variations on the UVIS Detector

Breathing, Position Drift, and PSF Variations on the UVIS Detector SPACE TELESCOPE SCIENCE INSTITUTE Operated for NASA by AURA Instrument Science Report WFC3 1-1 Breathing, Position Drift, and PSF Variations on the UVIS Detector L. Dressel July 13, 1 ABSTRACT This study

More information

Updated Measurements of ACS/SBC Dark Rates

Updated Measurements of ACS/SBC Dark Rates Instrument Science Report ACS 2017-04 Updated Measurements of ACS/SBC Dark Rates R.J. Avila May 3, 2017 Abstract The results of dark rate monitoring programs for the ACS/SBC are presented here. The dark

More information

Photometric Techniques II Data analysis, errors, completeness

Photometric Techniques II Data analysis, errors, completeness Photometric Techniques II Data analysis, errors, completeness Sergio Ortolani Dipartimento di Astronomia Universita di Padova, Italy. The fitting technique assumes the linearity of the intensity values

More information

Lab 4 Radial Velocity Determination of Membership in Open Clusters

Lab 4 Radial Velocity Determination of Membership in Open Clusters Lab 4 Radial Velocity Determination of Membership in Open Clusters Sean Lockwood 1, Dipesh Bhattarai 2, Neil Lender 3 December 2, 2007 Abstract We used the Doppler velocity of 29 stars in the open clusters

More information

A Cross-Calibration between Tycho-2 Photometry and Hubble Space Telescope Spectrophotometry

A Cross-Calibration between Tycho-2 Photometry and Hubble Space Telescope Spectrophotometry Publications of the Astronomical Society of the Pacific, 117:615 619, 2005 June 2005. he Astronomical Society of the Pacific. All rights reserved. Printed in U.S.A. A Cross-Calibration between ycho-2 Photometry

More information

Persistence in the WFC3 IR Detector: Spatial Variations

Persistence in the WFC3 IR Detector: Spatial Variations SPACE TELESCOPE SCIENCE INSTITUTE Operated for NASA by AURA WFC3 Instrument Science Report 2015-16 Persistence in the WFC3 IR Detector: Spatial Variations Knox S. Long, Sylvia M. Baggett, & John W. MacKenty

More information

WFC3 Cycle 18 Calibration Program

WFC3 Cycle 18 Calibration Program Instrument Science Report WFC3 2011-14 WFC3 Cycle 18 Calibration Program S. Deustua June 30 2011 The WFC3 Cycle 18 Calibration Program runs from October 2010 through September 2011, and will measure and

More information

WFC3/IR Persistence as Measured in Cycle 17 using Tungsten Lamp Exposures

WFC3/IR Persistence as Measured in Cycle 17 using Tungsten Lamp Exposures WFC3/IR Persistence as Measured in Cycle 17 using Tungsten Lamp Exposures Knox S. Long, Sylvia Baggett, Susana Deustua & Adam Riess November 17, 2010 ABSTRACT Like most IR arrays, the IR detector incorporated

More information

WFPC2 Dark Current vs. Time

WFPC2 Dark Current vs. Time WFPC2 Dark Current vs. Time J. Mack, J. Biretta, S. Baggett, C. Proffitt June 7, 2001 ABSTRACT On-going measurements of the dark current in the WFPC2 detectors indicate that the average level of dark current

More information

WFC3/UVIS Photometric Transformations

WFC3/UVIS Photometric Transformations Instrument Science Report WFC3 2014-016 WFC3/UVIS Photometric Transformations Kailash Sahu, Susana Deustua and Elena Sabbi January 05, 2017 ABSTRACT We provide photometric transformation coefficients for

More information

Accuracy of the HST Standard Astrometric Catalogs w.r.t. Gaia

Accuracy of the HST Standard Astrometric Catalogs w.r.t. Gaia Instrument Science Report WFC3 2018-01 Accuracy of the HST Standard Astrometric Catalogs w.r.t. Gaia V. Kozhurina-Platais, N. Grogin, E. Sabbi February 16, 2018 Abstract The goal of astrometric calibration

More information

The Effective Spectral Resolution of the WFC and HRC Grism

The Effective Spectral Resolution of the WFC and HRC Grism The Effective Spectral Resolution of the WFC and HRC Grism A. Pasquali, N. Pirzkal, J.R. Walsh, R.N. Hook, W. Freudling, R. Albrecht, R.A.E. Fosbury March 7, 2001 ABSTRACT We present SLIM simulations of

More information

SPACE TELESCOPE SCIENCE INSTITUTE. ACS Polarization Calibration: Introduction and Progress Report

SPACE TELESCOPE SCIENCE INSTITUTE. ACS Polarization Calibration: Introduction and Progress Report 1 ACS Polarization Calibration: Introduction and Progress Report J. Biretta, V. Platais, F. Boffi, W. Sparks, J. Walsh Introduction: Theory / ACS Polarizers / Supported Modes Potential Issues for ACS Polarization

More information

Addendum: GLIMPSE Validation Report

Addendum: GLIMPSE Validation Report August 18, 2004 Addendum: GLIMPSE Validation Report The GLIMPSE Team 1. Motivation In our Validation Report of Jan. 30, 2004, we produced reliability calculations and discussed photometric accuracy estimates

More information

NICMOS Focus Field Variations (FFV) and Focus Centering

NICMOS Focus Field Variations (FFV) and Focus Centering Instrument Science Report NICMOS-98-005 NICMOS Focus Field Variations (FFV) and Focus Centering A.Suchkov & G.Galas March 16, 1998 ABSTRACT NICMOS foci are known to vary across detector s field of view.

More information

Data Reduction - Optical / NIR Imaging. Chian-Chou Chen Ph319

Data Reduction - Optical / NIR Imaging. Chian-Chou Chen Ph319 Data Reduction - Optical / NIR Imaging Chian-Chou Chen (T.C.) @ Ph319 Images at different wavelengths... Images at different wavelengths... However, the raw data are always not as pretty Why? The total

More information

Chapter 6: Transforming your data

Chapter 6: Transforming your data Why is transformation necessary? Chapter 6: Transforming your data The AAVSO International Database is composed of data collected from many different observers, at different times, from around the globe.

More information

Calibration Goals and Plans

Calibration Goals and Plans CHAPTER 13 Calibration Goals and Plans In This Chapter... Expected Calibration Accuracies / 195 Calibration Plans / 197 This chapter describes the expected accuracies which should be reached in the calibration

More information

Predicted Countrates for the UV WFC3 Calibration Subsystem using Deuterium Lamps

Predicted Countrates for the UV WFC3 Calibration Subsystem using Deuterium Lamps Predicted Countrates for the UV WFC3 Calibration Subsystem using Deuterium Lamps S.Baggett, J. Sullivan, and M. Quijada May 17,24 ABSTRACT Predicted WFC3 calibration subsystem countrates have been computed

More information

XMM-Newton Optical-UV Monitor: introduction and calibration status OM instrument and calibration

XMM-Newton Optical-UV Monitor: introduction and calibration status OM instrument and calibration XMM-Newton Optical-UV Monitor: introduction and calibration status OM instrument and calibration Antonio Talavera XMM-Newton Science Operation Centre, ESAC, ESA OM: Instrument Description 30 cm Ritchey-Chretien

More information

On the calibration of WFCAM data from 2MASS

On the calibration of WFCAM data from 2MASS On the calibration of WFCAM data from 2MASS Authors: Simon Hodgkin, Mike Irwin Draft: September 28 th 2006 Modifications: ID: VDF-TRE-IOA-00011-0000* 1 Introduction The requirement on VDFS is to photometrically

More information

WFPC2 Cycle 7 Calibration Plan

WFPC2 Cycle 7 Calibration Plan Instrument Science Report WFPC2-97-06 WFPC2 Cycle 7 Calibration Plan S. Casertano and the WFPC2 group August 18, 1997 ABSTRACT This report describes in detail the WFPC2 observations planned to maintain

More information

UVIT IN ORBIT CALIBRATIONS AND CALIBRATION TOOLS. Annapurni Subramaniam IIA (On behalf of the UVIT team)

UVIT IN ORBIT CALIBRATIONS AND CALIBRATION TOOLS. Annapurni Subramaniam IIA (On behalf of the UVIT team) UVIT IN ORBIT CALIBRATIONS AND CALIBRATION TOOLS Annapurni Subramaniam IIA (On behalf of the UVIT team) Calibrations: : Calibrations are of two types: 1. Ground calibrations 2. In orbit calibrations In

More information

11041,11042,11043: ACS CCD Daily Monitor

11041,11042,11043: ACS CCD Daily Monitor 11041,11042,11043: ACS CCD Daily Monitor Purpose. This program consists of a series of basic tests to measure the readnoise and dark current of the ACS CCDs and to track the growth of hot pixels. The images

More information

An Algorithm for Correcting CTE Loss in Spectrophotometry of Point Sources with the STIS CCD

An Algorithm for Correcting CTE Loss in Spectrophotometry of Point Sources with the STIS CCD An Algorithm for Correcting CTE Loss in Spectrophotometry of Point Sources with the STIS CCD Ralph Bohlin and Paul Goudfrooij August 8, 2003 ABSTRACT The correction for the change in sensitivity with time

More information

Impacts of focus on aspects of STIS UV Spectroscopy

Impacts of focus on aspects of STIS UV Spectroscopy Instrument Science Report STIS 2018-06 Impacts of focus on aspects of STIS UV Spectroscopy Allyssa Riley 1, TalaWanda Monroe 1, & Sean Lockwood 1 1 Space Telescope Science Institute, Baltimore, MD November

More information

Space-Based Imaging Astrometry: Life with an Undersampled PSF. Jay Anderson STScI Feb 15, 2012

Space-Based Imaging Astrometry: Life with an Undersampled PSF. Jay Anderson STScI Feb 15, 2012 Space-Based Imaging Astrometry: Life with an Undersampled PSF Jay Anderson STScI Feb 15, 2012 Overview of the Talk Astrometry with HST 3 critical issues Science General Microlensing Extensions to WFIRST

More information

Improving the Absolute Astrometry of HST Data with GSC-II

Improving the Absolute Astrometry of HST Data with GSC-II The 2005 HST Calibration Workshop Space Telescope Science Institute, 2005 A. M. Koekemoer, P. Goudfrooij, and L. L. Dressel, eds. Improving the Absolute Astrometry of HST Data with GSC-II A. M. Koekemoer,

More information

XMM-Newton Calibration

XMM-Newton Calibration XMM-Newton Calibration Michael Smith, on behalf of XMM-SOC and Instrument Teams 18 th XMM-Newton Users Group Meeting, ESAC, 11 May 2017 ESA UNCLASSIFIED - For Official Use Outline 1. Status of calibration

More information

WFPC2 Clocks-ON Close Out

WFPC2 Clocks-ON Close Out WFPC2 Clocks- Close Out.. Schultz, S. aggett, J. iretta January 17, 2 STRCT We present results from an analysis of WFPC2 standard star observations and dark frames obtained with the serial clocks. The

More information

Project for Observational Astronomy 2017/2018: Colour-magnitude diagram of an open cluster

Project for Observational Astronomy 2017/2018: Colour-magnitude diagram of an open cluster Project for Observational Astronomy 017/018: Colour-magnitude diagram of an open cluster Søren S. Larsen December 13, 017 1 1 Colour-magnitude diagram for an open cluster 1.1 Background The colour-magnitude

More information

C. Watson, E. Churchwell, R. Indebetouw, M. Meade, B. Babler, B. Whitney

C. Watson, E. Churchwell, R. Indebetouw, M. Meade, B. Babler, B. Whitney Reliability and Completeness for the GLIMPSE Survey C. Watson, E. Churchwell, R. Indebetouw, M. Meade, B. Babler, B. Whitney Abstract This document examines the GLIMPSE observing strategy and criteria

More information

WFPC2 Status and Overview

WFPC2 Status and Overview 2002 HST Calibration Workshop Space Telescope Science Institute, 2002 S. Arribas, A. Koekemoer, and B. Whitmore, eds. WFPC2 Status and Overview B. C. Whitmore Space Telescope Science Institute, 3700 San

More information

Dark Rate of the STIS NUV Detector

Dark Rate of the STIS NUV Detector SPACE TELESCOPE SCIENCE INSTITUTE Operated for NASA by AURA Instrument Science Report STIS 2011-03 Dark Rate of the STIS NUV Detector Wei Zheng 1, Charles Proffitt 2, and David Sahnow 1 1 Department of

More information

COS FUV Dispersion Solution Verification at the New Lifetime Position

COS FUV Dispersion Solution Verification at the New Lifetime Position SPACE TELESCOPE SCIENCE INSTITUTE Operated for NASA by AURA Instrument Science Report COS 2013-06(v1) COS FUV Dispersion Solution Verification at the New Lifetime Position Paule Sonnentrucker 1, Julia

More information

TIPS-JIM Meeting 13 October 2005, 10am, Auditorium

TIPS-JIM Meeting 13 October 2005, 10am, Auditorium TIPS-JIM Meeting 13 October 2005, 10am, Auditorium 1. The Mid-Infrared Instrument (MIRI) Martyn Wells Medium Resolution Spectrometer for JWST 2. Temperature changes for ACS CCDs: Marco Sirianni Initial

More information

A Recalibration of Optical Photometry Based on STIS Spectrophotometry

A Recalibration of Optical Photometry Based on STIS Spectrophotometry The 2005 HST Calibration Workshop Space Telescope Science Institute, 2005 A. M. Koekemoer, P. Goudfrooij, and L. L. Dressel, eds. A Recalibration of Optical Photometry Based on STIS Spectrophotometry J.

More information

Performance of the NICMOS ETC Against Archived Data

Performance of the NICMOS ETC Against Archived Data Performance of the NICMOS ETC Against Archived Data M. Sosey June 19, 2001 ABSTRACT A robust test of the newest version of the NICMOS Exposure Time Calculator (ETC) was conducted in order to assess its

More information

The TV3 ground calibrations of the WFC3 NIR grisms

The TV3 ground calibrations of the WFC3 NIR grisms The TV3 ground calibrations of the WFC3 NIR grisms H. Kuntschner, H. Bushouse, J. R. Walsh, M. Kümmel July 10, 2008 ABSTRACT Based on thermal vacuum tests (TV3; March/April 2008), the performance of the

More information

Impressions: First Light Images from UVIT in Orbit

Impressions: First Light Images from UVIT in Orbit Impressions: First Light Images from UVIT in Orbit Drafted by S N Tandon on behalf of UVIT team. December 4, 2015; V1.0 1. Introduction: Ultraviolet Imaging Telescope (UVIT) is the long wavelength eye

More information

HST Temporal Optical Behavior: Models and Measurements with ACS

HST Temporal Optical Behavior: Models and Measurements with ACS 2005 HST Calibration Workshop Space Telescope Science Institute, 2005 A. Koekemoer, P. Goudfrooij, and L. Dressel, eds. HST Temporal Optical Behavior: Models and Measurements with ACS R. B. Makidon, S.

More information

Observer Anomaly(?): Recent Jitter and PSF Variations

Observer Anomaly(?): Recent Jitter and PSF Variations Instrument Science Report TEL 2005-01 Observer Anomaly(?): Recent Jitter and PSF Variations R. L. Gilliland gillil@stsci.edu February 2005 Abstract An anomaly in the HST Pointing Control System (PCS) has

More information

BetaDrizzle: A Redesign of the MultiDrizzle Package

BetaDrizzle: A Redesign of the MultiDrizzle Package The 2010 STScI Calibration Workshop Space Telescope Science Institute, 2010 Susana Deustua and Cristina Oliveira, eds. BetaDrizzle: A Redesign of the MultiDrizzle Package A. S. Fruchter, W. Hack, N. Dencheva,

More information

Reduction procedure of long-slit optical spectra. Astrophysical observatory of Asiago

Reduction procedure of long-slit optical spectra. Astrophysical observatory of Asiago Reduction procedure of long-slit optical spectra Astrophysical observatory of Asiago Spectrograph: slit + dispersion grating + detector (CCD) It produces two-dimension data: Spatial direction (x) along

More information

Early-Science call for observing time with SAM-FP

Early-Science call for observing time with SAM-FP Early-Science call for observing time with SAM-FP 1. General description SOAR is opening a call for proposals for early-science with SAM-FP in 2016B, for 4 nights (September 29 October 2, 2016). SAM-FP

More information

Trails of solar system minor bodies on WFC/ACS images q

Trails of solar system minor bodies on WFC/ACS images q New Astronomy 9 (2004) 679 685 www.elsevier.com/locate/newast Trails of solar system minor bodies on WFC/ACS images q Simone Marchi, Yazan Momany, Luigi R. Bedin * Dipartimento di Astronomia, Università

More information

Detecting Cosmic Rays in Infrared Data

Detecting Cosmic Rays in Infrared Data The 2010 STScI Calibration Workshop Space Telescope Science Institute, 2010 Susana Deustua and Cristina Oliveira, eds. Detecting Cosmic Rays in Infrared Data Rachel E. Anderson and Karl Gordon Space Telescope

More information

Analysis of Hubble Legacy Archive Astrometric Header Information

Analysis of Hubble Legacy Archive Astrometric Header Information Analysis of Hubble Legacy Archive Astrometric Header Information Michael A. Wolfe and Stefano Casertano ABSTRACT Astrometric information is put into the headers of the final drizzled images produced by

More information

Part III: Circumstellar Properties of Intermediate-Age PMS Stars

Part III: Circumstellar Properties of Intermediate-Age PMS Stars 160 Part III: Circumstellar Properties of Intermediate-Age PMS Stars 161 Chapter 7 Spitzer Observations of 5 Myr-old Brown Dwarfs in Upper Scorpius 7.1 Introduction Ground-based infrared studies have found

More information

Wavelength Calibration Accuracy for the STIS CCD and MAMA Modes

Wavelength Calibration Accuracy for the STIS CCD and MAMA Modes SPACE TELESCOPE SCIENCE INSTITUTE Operated for NASA by AURA Instrument Science Report STIS 11-1(v1) Wavelength Calibration Accuracy for the STIS CCD and MAMA Modes Ilaria Pascucci 1, Phil Hodge 1, Charles

More information

Point-Source CCD Photometry with STIS: Correcting for CTE loss

Point-Source CCD Photometry with STIS: Correcting for CTE loss SPACE TELESCOPE SCIENCE INSTITUTE Operated for NASA by AURA Point-Source CCD Photometry with STIS: Correcting for CTE loss Space Telescope Science Institute Methods to measure CTE of STIS CCD (Visual)

More information

Introduction to SDSS -instruments, survey strategy, etc

Introduction to SDSS -instruments, survey strategy, etc Introduction to SDSS -instruments, survey strategy, etc (materials from http://www.sdss.org/) Shan Huang 17 February 2010 Survey type Status Imaging and Spectroscopy Basic Facts SDSS-II completed, SDSS-III

More information

Chandra Source Catalog Energy Bands

Chandra Source Catalog Energy Bands Chandra Source Catalog Energy Bands Michael L. McCollough, CXC/SAO January 26, 2007 Abstract: Given below is the rational for deciding the energy bands and their associated effective energy (mono-energy

More information

Annapurni Subramaniam IIA UVIT-PMB Meeting 08 June 2012

Annapurni Subramaniam IIA UVIT-PMB Meeting 08 June 2012 UVIT IN ORBIT CALIBRATIONS Annapurni Subramaniam IIA UVIT-PMB Meeting 08 June 2012 UVIT Telescope various components Calibrations are of two types: 1. Ground calibrations 2. In orbit calibrations In general,

More information

Sub-percent Accuracy for a Factor of a Million in Flux

Sub-percent Accuracy for a Factor of a Million in Flux WFC3 Instrument Science Report 2019-01 Calibration of the WFC3-IR Count-rate Nonlinearity, Sub-percent Accuracy for a Factor of a Million in Flux A. G. Riess, Gautham Narayan, Annalisa Calamida January

More information

Flat Fields and Flux Calibrations for the COS FUV Channel at Lifetime Position 4

Flat Fields and Flux Calibrations for the COS FUV Channel at Lifetime Position 4 Instrument Science Report COS 2018-20(v1) Flat Fields and Flux Calibrations for the COS FUV Channel at Lifetime Position 4 William J. Fischer 1, Marc Rafelski 1, and Gisella de Rosa 1 1 Space Telescope

More information

The Behaviour of the XMM-Newton Background: From the beginning of the mission until May XMM-SOC-GEN-TN-0014 issue 3.10

The Behaviour of the XMM-Newton Background: From the beginning of the mission until May XMM-SOC-GEN-TN-0014 issue 3.10 The Behaviour of the XMM-Newton Background: From the beginning of the mission until May 2017 XMM-SOC-GEN-TN-0014 issue 3.10 R. González-Riestra and P.M. Rodríguez-Pascual XMM-SOC User Support Group June

More information

Verification of COS/FUV Bright Object Aperture (BOA) Operations at Lifetime Position 3

Verification of COS/FUV Bright Object Aperture (BOA) Operations at Lifetime Position 3 Instrument Science Report COS 2015-05(v1) Verification of COS/FUV Bright Object Aperture (BOA) Operations at Lifetime Position 3 Andrew Fox 1, John Debes 1, & Julia Roman-Duval 1 1 Space Telescope Science

More information

Supplementary Materials for

Supplementary Materials for Supplementary Materials for The Shortest Known Period Star Orbiting our Galaxy's Supermassive Black Hole L. Meyer, A. M. Ghez, R. Schödel, S. Yelda, A. Boehle, J. R. Lu, T. Do, M. R. Morris, E. E. Becklin,

More information

arxiv: v1 [astro-ph.sr] 29 Jan 2009

arxiv: v1 [astro-ph.sr] 29 Jan 2009 ACTA ASTRONOMICA Vol. 58 (28) pp. 329 343 arxiv:91.4632v1 [astro-ph.sr] 29 Jan 29 The Optical Gravitational Lensing Experiment. OGLE-III Photometric Maps of the Small Magellanic Cloud A. U d a l s k i

More information

1. Give short answers to the following questions. a. What limits the size of a corrected field of view in AO?

1. Give short answers to the following questions. a. What limits the size of a corrected field of view in AO? Astronomy 418/518 final practice exam 1. Give short answers to the following questions. a. What limits the size of a corrected field of view in AO? b. Describe the visibility vs. baseline for a two element,

More information

The HST Set of Absolute Standards for the 0.12 µm to 2.5 µm Spectral Range

The HST Set of Absolute Standards for the 0.12 µm to 2.5 µm Spectral Range Instrument Science Report CAL/SCS-010 The HST Set of Absolute Standards for the 0.12 µm to 2.5 µm Spectral Range L. Colina, R. Bohlin, D. Calzetti, C. Skinner, S. Casertano October 3, 1996 ABSTRACT A proposal

More information

Globular Clusters in M87

Globular Clusters in M87 Globular Clusters in M87 Tutor: Søren S. Larsen First NEON Archive Observing School 2004 Avet Harutyunyan Saskia Hekker Anatoliy Ivantsov Loredana Vetere Contents Globular Clusters Introduction Data Retrieving

More information

RADIATION DAMAGE IN HST DETECTORS

RADIATION DAMAGE IN HST DETECTORS RADIATION DAMAGE IN HST DETECTORS Marco Sirianni, European Space Agency, Space Telescope Science Institute Max Mutchler, Space Telescope Science Institute Abstract: Key words: We present an analysis of

More information