Transforming observational data and theoretical isochrones into the ACS/WFC Vega-mag system

By L. Bedin, Santi Cassisi, F. Castelli, G. Piotto, Jay Anderson, Maurizio Salaris, Y. Momany, Adriano Pietrinferni . Univ.PD, E.S.O.-Garching, INAF-Obs.Teramo and 4 more. 2004

146 citations recorded by the source corpus.

We propose a zero-point photometric calibration of the data from the Advanced Camera for Surveys (ACS) Wide Field Channel (WFC) on board the Hubble Space Telescope, based on a spectrum of Vega and the most up-to-date in-flight transmission curves of the camera. This calibration is accurate at the level of a few hundredths of a magnitude. The main purpose of this effort is to transform the entire set of evolutionary models into a simple observational photometric system for ACS/WFC data, and to make them available to the astronomical community. We provide the zero-points for the most used ACS/WFC bands, and give basic recipes for calibrating both the observed data and the models. We also present the colour-magnitude diagram from ACS data of five Galactic globular clusters, spanning the metallicity range -2.2 <[Fe/H] < -0.04, and we provide fiducial points representing their sequences from several magnitudes below the turn-off to the red giant branch tip. The observed sequences are compared with the models in the newly defined photometric system.

Subfields: Astronomy and Astrophysics

View Paper: https://www.semanticscholar.org/paper/6f2b61e30561cd1f4e0cfe415e54044f379b73ae

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In Astronomy and Astrophysics

1. Jay Anderson
2. G. Piotto
3. Aaron Dotter
4. C. Conroy
5. A. Milone
6. L. Bedin
7. R. Gratton
8. F. D’Antona

Citations in the corpus

• The White Dwarf Cooling Sequence of NGC 6397 (2005, methodology): “The calibration to the ACS Vega-mag system was done following the recipes in Bedin et al. (2005).”
• The ACS Survey of Galactic Globular Clusters. II. Stellar Evolution Tracks, Isochrones, Luminosity Functions, and Synthetic Horizontal-Branch Models (2007, methodology): “The procedure followed to derive the Synthetic transformation closely follows that of Bedin et al. (2005).”
• The ACS Survey of Galactic Globular Clusters. I. Overview and Clusters without Previous Hubble Space Telescope Photometry (2006, methodology): “We calibrate the photometry to the ACSWFCVEGAmag system, following the procedure given in Bedin et al. (2005) using the most updated encircled energy distributions and the official zero points given by Sirianni et al. (2005).”
• A Triple Main Sequence in the Globular Cluster NGC 2808 (2007, methodology): “The photometry was put into the WFC/ACS Vega-mag system according to the proce- dure given in Bedin et al. (2005), and using the encircled energy and zero points given by Sirianni et al. (2005).”
• The Dartmouth Stellar Evolution Database (2008, methodology): “Bedin et al. (2005) defined a method for generating synthetic photometry based on the detailed filter transmission curves for the Hubble Space Telescope (HST) Advanced Camera for Surveys (ACS) and Wide Field Planetary Camera 2 (WFPC2) from Sirianni et al. (2005).”
• The ACS Survey of Galactic Globular Clusters. III. The Double Subgiant Branch of NGC 1851 (2007, methodology): “We put the WFC photometry into the VEGAMAG system following the procedures in Bedin et al. (2005), and adopting the encircled energy and zero points as given by Sirianni et al. (2005).”
• THE ACS SURVEY OF GLOBULAR CLUSTERS. V. GENERATING A COMPREHENSIVE STAR CATALOG FOR EACH CLUSTER (2008, methodology): “We therefore measured a few dozen isolated bright stars in the the drz images, using the procedure detailed in Bedin et al. (2005).”
• THE AGES OF 55 GLOBULAR CLUSTERS AS DETERMINED USING AN IMPROVED METHOD ALONG WITH COLOR–MAGNITUDE DIAGRAM CONSTRAINTS, AND THEIR IMPLICATIONS FOR BROADER ISSUES (2013, methodology): “Because MARCS model atmospheres were not computed for Teff values > 8000 K, the aforementioned transformations were supplemented by the BCs for hotter stars that were kindly provided to us by S. Cassisi (private communication, also see Bedin et al. 2005).”
• A Large Stellar Evolution Database for Population Synthesis Studies. II. Stellar Models and Isochrones for an α-enhanced Metal Distribution (2006, result): “Our α-enhanced isochrones have been already compared to globular cluster (GC) CMDs in the ACS filters (Bedin et al. 2005) and employed to determine the initial He content (from the theoretical calibration of the R-parameter), distances (from the theoretical ZAHB models), reddening and relative ages…”
• The Multiplicity of the Subgiant Branch of ω Centauri: Evidence for Prolonged Star Formation (2007, methodology): “The instrumental magnitudes were transformed into the ACS Vega-mag flight system following the procedure given in Bedin et al. (2005), using the zero points of Sirianni et al. (2005).”
• The fraction of second generation stars in globular clusters from the analysis of the horizontal branch (2008, methodology): “The transformations for the ACS – HST bands are taken from Bedin et al. (2005).”
• Multiple stellar populations in Magellanic Cloud clusters - I. An ordinary feature for intermediate age globulars in the LMC? (2008, methodology): “Calibration of ACS photometry into the Vega-mag system was performed following recipes in Bedin et al. (2005) and using the zero points given in Sirianni et al. (2005).”
• A WFC3/HST VIEW OF THE THREE STELLAR POPULATIONS IN THE GLOBULAR CLUSTER NGC 6752 (2013, methodology): “For ACS/WFC filters we used the extinction coefficients tabulated by Bedin et al. (2005) for a cold (T=4000K) star.”
• The Double Subgiant Branch of NGC 1851: The Role of the CNO Abundance (2007, methodology): “Bolometric luminosities and effective temperatures of the models and isochrones for the two metal mixtures have been transformed into magnitudes and colors using the transformations presented by Bedin et al. (2005), for [Fe/H] p 1.3.”
• THE ACS NEARBY GALAXY SURVEY TREASURY (2007, background): “The systems will also differ for stars of a different color than Vega to the extent that the system response 21 Note that the Bedin et al. (2005) ACS calibration also as- 10 Dalcanton et al. of the ACS F814W filter+camera+detector system differs from that of WFPC2.”
• GLOBULAR CLUSTERS IN THE OUTER GALACTIC HALO: NEW HUBBLE SPACE TELESCOPE/ADVANCED CAMERA FOR SURVEYS IMAGING OF SIX GLOBULAR CLUSTERS AND THE GALACTIC GLOBULAR CLUSTER AGE–METALLICITY RELATION (2011, methodology): “The instrumental photometry was then calibrated to the HST VEGAmag system following Bedin et al. (2005) and using the aperture corrections from Sirianni et al. (2005) as described by Sarajedini et al. (2007) and Anderson et al. (2008).”
• MULTIPLE STELLAR POPULATIONS IN 47 Tucanae (2011, methodology): “To determine the absorption in the F814W band we used the relations given by Bedin et al. (2005).”