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HST and Astrometry in the 2010 Decade

HST and Astrometry in the 2010 Decade. William van Altena Yale University, New Haven, CT USA. With thanks to : Jay Anderson Rolly Bedin Dave Monet Norbert Zacharias. Terry Girard Dana Casetti Elliott Horch Imants Platais Todd Henry. Fritz Benedict Barbara McArthur Art Bradley

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HST and Astrometry in the 2010 Decade

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  1. HST and Astrometry in the 2010 Decade William van Altena Yale University, New Haven, CT USA With thanks to: Jay Anderson Rolly Bedin Dave Monet Norbert Zacharias Terry Girard Dana Casetti Elliott Horch Imants Platais Todd Henry Fritz Benedict Barbara McArthur Art Bradley René Méndez Andrea Ghez HST Cal. WS: July 21-23, 2010

  2. Astrometry in the 21st century • Analyze data contained in large multipurpose surveys • SDSS, 2MASS, PanSTARRS, LSST, etc. • Extract relevant data from astrometric surveys • UCAC, SPM, NPM • PI projects on medium to large multipurpose telescopes • HST, 4-m telescopes, 8-10-m large telescopes • Small PI projects on dedicated astrometric telescopes • USNO 1.5-m astrometric reflector • UCAC 0.25-m astrograph • SPM 0.50-m astrograph, etc. • Educational use of small ground-based telescopes • Instrumentation development HST Cal. WS: July 21-23, 2010

  3. Ground vs Space Astrometry • Where ground-based Astrometry will remain important • Ground-based parallax errors can be as low as 0.25 mas, almost as accurateas HST FGS which are about 0.20 mas. • Beware of relying on very large “root n” • N > 100: systematic errors may dominate • Targets fainter than magnitude 16 can be reached, much fainter than FGS astrometry.  • Binary stars will be done primarily by speckle interferometry from the ground.  • Strong role for ground-based astrometry until Gaia results are available.  • After Gaia proper motions and positions will be determined from the ground using a Gaia reference frame. • Where space-based Astrometry will remain important • Crowded regions such as the centers of globular clusters • Projects requiring high-precision individual observations HST Cal. WS: July 21-23, 2010

  4. HST Astrometry • Surveys • Deep fields (1995 HDF, 1998 HDFS, 2003 HUDF) • Crowded regions • Globular Clusters (pm membership, absolute pms & orbits) • Magellanic Clouds (absolute pms & orbits) • Parallaxes • Special objects (Planetary nebulae, novae, neutron stars, …) • Cepheid Pop I and II P-L relations • Binaries • Masses and orbits (close binaries) • Extra-Solar planets (perturbation astrometry of nearby stars) HST Cal. WS: July 21-23, 2010

  5. Current astrometric surveys UCAC NPM SPM Schmidt plate scans USNO-A2, USNO-B SuperCosmos Planned astrometric surveys URAT Current multipurpose surveys SDSS and derivatives 2MASS Dennis SkyMapper PanSTARRS Planned multipurpose surveys LSST Ground-based surveys current and future HST Cal. WS: July 21-23, 2010

  6. Current Astrometric Surveys • UCAC3: U.S. Naval Observatory CCD Astrograph Catalog • A compiled, all-sky star catalog of 100 million stars • Magnitude range 9 < R < 16 • Positional errors: 15 to 20 mas for 10 < R < 14 • Proper motions from early epoch SPM data (-90 to -10 deg Dec) and Schmidt plate data • Zacharias, et al. 2009 • SPM4: Yale/San Juan Southern Proper Motion Catalog 4: (2009) • NPMx: Lick Northern Proper Motion Catalog: first epoch positions: (2010) to be used as first-epoch positions for the UCAC4. • 103,319,647 stars and galaxies south of -20 degrees declination - SPM. • 160,000,000 stars and galaxies north of -30 degrees declination - NPM. • roughly complete to V=17.5 (all are contained in 2MASS) • precision of SPM4 positions: 30 to 150 mas • precision of SPM4 absolute proper motions: 2 to 10 mas/yr • van Altena, et al. 2009; Girard, et al. 2010 HST Cal. WS: July 21-23, 2010

  7. URAT: USNO Robotic Astrometric Telescope Magnitude range 9 < R < 16 Positional errors: 15 to 20 mas for 10 < R < 14 Proper motions from early epoch SPM data (-90 to -10 deg Dec) and Schmidt plate data Zacharias, et al. 2009 Future Astrometric Survey 51-cm double astrograph 110 megapixel CCD "superchip" 20-cm astrograph UCAC SPM URAT HST Cal. WS: July 21-23, 2010

  8. ROE SuperCOSMOS scanner Schmidt Plate Scanners STScI Guide Star Measuring Machine USNO PMM Measuring Machine HST Cal. WS: July 21-23, 2010

  9. GSC 2.3 release of GSC II 945,592,683 objects measured on STScI PDS machines GSC 2.3 is a current catalog release extracted from the Guide Star Catalog II database Positions on ICRF ACT/Tycho Bucciarelli, et al. 2008 SuperCOSMOS 1.9 billion objects Average J2000 positions and proper motions from 3 colors at 2 epochs Positions on Tycho2 and ACT http://surveys.roe.ac.uk/ssa/ USNO-A2 526,280,881 stars measured on PMM Average J2000 position on red and blue POSS plates ACT/Tycho system Monet, et al. 1998 USNO-B 1 billion stars Average J2000 positions and proper motions from 3 colors at 2 epochs Monet, et al. 2003 XPM: 2MASS - USNO-A2.0 280 million stars - whole sky Positions and proper motions Mag range 12 < B < 19 mag Federov, et al. 2009 Schmidt Plate Scans HST Cal. WS: July 21-23, 2010

  10. Multipurpose Surveys • General characteristics: • Not primarily astrometric, but huge amounts of useful data. • New surveys should get around 10-mas per visit; lots of visits and colors. • Surveys need much more input on astrometric needs. • Don’t need Gaia-class accuracy for nearby stars, etc. • Some priorities: • Develop algorithms for finding these needles in very big haystacks. • Understand astrometric accuracy: • Regime of low signal-to-noise ratios, short exposures, fast optics, etc. • Morphology and statistics of “reference galaxies”. • Contribute to design and mission of LSST. • Work on IR version of large etendue telescope+camera. HST Cal. WS: July 21-23, 2010

  11. Multipurpose Surveys 2MASS - A large-area, deep photometric survey SDSS based proper motions SDSS-USNO-B Covers about 3000 square degrees Sigma pm about 3.5 mas/yr. Munn, et al. AJ 127, 3034, 2004 & AJ 136, 895, 2008 SDSS-Flagstaff 1.3-m telescope Covers about 3000 square degrees Proper motion accuracy about 20-30 mas/yr with a 5-year baseline. Munn, et al. AAS 215, 45202, 2009 SDSS-SDSS proper motions 300 square degree Southern Equatorial Stripe Pan-STARRS 1.8-m Sky Survey Pan-STARRS will survey the whole sky to 24th magnitude every few days SkyMapper - ANU 1.35-m survey analogous to the Sloan Digital Sky Survey; 20,000 sq. deg. South of equator. LSST - Large Synoptic Survey Telescope 8.4-m primary, 6.7-m effective aperture Ten-year imaging survey over 20,000 square degrees south of +15 deg. Each pointing will be imaged 1000 times with fifteen second exposures in total point-source depth of r~27.5. Gaia parallax accuracy at r = 20.5 mag and to go 4 mag fainter than Gaia HST Cal. WS: July 21-23, 2010

  12. Deep Astrometric Standards (DAS) • Large telescopes need deep and precise reference frames for astrometric calibrations. • Absolute astrometry at the 5 - 10 mas level and absolute proper motions good to 2 mas/yr in four 10 deg2 Galactic fields, to a depth of V=25. • Basic reference frame is UCAC2 catalog, significantly improved by additional observations, and new VLBI positions of radio-loud and optically visible QSOs. Platais, et al. 2006 (PASP 118, 107, 2006) Careful of LSST 15-sec exposures! HST Cal. WS: July 21-23, 2010

  13. Science in the Halo of the Galaxy • Dwarf galaxies and Globular Clusters • The formation of the GC system: accreted from early/recent mergers of satellites and/or formed in situ? • Orbits help to understand formation scenarios of the Galaxy and origins of GCs • Ground-based surveys & some HST provide absolute proper motions and orbits • Casetti, et al. (2010) • Rees & Cudworth (2010) • Bellini & Bedin (2010) HST Cal. WS: July 21-23, 2010

  14. Science in the Halo of the Galaxy • Magellanic Clouds • Ground-based pms imply systems probably bound to Galaxy • Vieira, et al. (2010) • HST-based pms imply systems probably unbound • Kallivayalil, et al. (2006, 2010) • Reference systems of galaxies & QSOs now provide the link to absolute • Gaia will be the link to absolute in the future HST Cal. WS: July 21-23, 2010

  15. Finding Merger Remnants from Surveys • Velocity dispersion in a remnant stream predicted Sigma v ~ ± 5 km/s (Helmi & White, 1999; Kathryn Johnston, 2006) • 300-500 remnant streams predicted by H&W within the local 1 kpc3 • Sigv = k*Sigpm*D • 5 km/sec = 4.74* Sigpm *1000pc • Sigpm = 1 mas/yr • Proper motions with sigpm = 0.5 mas/yr can now be determined with medium-sized telescopes in a 3-4 years to mag 21. • Detection/non-detection of streams could place limits on the validity of the lambda-CDM models of cosmology HST Cal. WS: July 21-23, 2010

  16. Measuring the orbit of Sgr streamCasetti, et al. 2010 Sgr core SA 71 SA 116 SA 94 SA 93 SA 117 HST Cal. WS: July 21-23, 2010

  17. Proper Motions in the Hubble Deep Field - North Kilic, von Hippel, Winget & Méndez, Ap J accepted. HST Cal. WS: July 21-23, 2010

  18. Globular Cluster Proper Motion Membership • HST imaging cameras enable us to determine precise relative proper motions. • This enables us to separate the cluster members from the field stars and therefore “clean” the CMDs. In some cases it is possible to study the internal dynamics of the clusters. • Proper motion precision of 0.25 mas/year for a 3 year baseline. • This corresponds to ≈10 km/s at 10 kpc. Anderson & King, 2003, “The Rotation of 47 Tuc,” AJ, 126, 772 HST Cal. WS: July 21-23, 2010

  19. 19 The First Full CMD of a Globular Cluster • Richer et al. 2005 observed NGC6397 with 126 orbits • Discoveries • End of WD cooling seq • Blue hook at bottom! • End of MS? • Limitation: field stars • Solution: proper motion membership • Slides courtesy of Jay Anderson HST Cal. WS: July 21-23, 2010

  20. 20.0 20.1 20.2 20.3 PI-Rich, UCLA Proper-Motion Cleaning HST Cal. WS: July 21-23, 2010

  21. Where are the stars centered? HST Cal. WS: July 21-23, 2010

  22. Open Cluster Membership • Low field density, so a ground-based project for Wide-Field Imagers • Proper motion precision now available with time baseline of 3-4 years: • igmapm ~ ± 0.5 mas/yr, or • igmav ~ ± 2.6 km/s @ 1kpc • Very clean separation of members from field stars for clusters with D < 1-2 kpc HST Cal. WS: July 21-23, 2010

  23. The Stellar Census and Dark Matter • Ground-based programs • USNO Flagstaff (Dahn, et al. 2008) • Special objects with parallax precision of 0.25 mas • RECONS at CTIO (Henry) • Parallaxes with wide-field imagers on the ground. • ±1 mas positional astrometry can yield 0.5 mas parallax precision. • Determine stellar density to 2% in Solar Nbhd. • Brown dwarfs, L & T dwarfs • Detect to MI ≤ 21 at 150 pc Courtesy of Todd Henry HST Cal. WS: July 21-23, 2010

  24. HST FGS parallaxes • HST FGS • Stars brighter than 16th mag • Parallax precision to 0.2 mas • Pop I Cepheid P-L calibration - 2007 • Planetary nebulae - 2009 • Pop II Cepheid P-L calibration - HST orbits approved. • Benedict, et al. 2007, 2009 Pop I Cepheid P-L calibration HST Cal. WS: July 21-23, 2010

  25. HST FGS parallaxes of Planetary Nebulae Benedict, et al. 2009 HST Cal. WS: July 21-23, 2010

  26. N r Binaries:Orbits and masses. • Binary stars. • Gravitation --> orbit. • Semi-major axis from • ground-based speckle interferometry • HST FGS scans • separations down to 10-15 mas with FGS. • Need SIZE of orbit which means we need the parallax. • Gaia and SIM will do the job here. HST Cal. WS: July 21-23, 2010

  27. 4 years, from 11 pc The  And System McArthur, et al. 2010 50 y of Solar System from 10 pc

  28. Adaptive Optics • Adaptive optics: correct for atmospheric turbulence in Infrared • Can see through the 20 magnitudes of visual extinction • Very small areas of the sky, say 1” • Need a fairly bright reference star to monitor the atmosphere, so limited unless laser reference is used • Mass of Black Hole at the Galactic center from orbital motions of the stars HST Cal. WS: July 21-23, 2010

  29. Space Satellite accuracy projections Gaia and SIM will determine the parallaxes that with orbits from HST FGS, while ground- based Speckle Interferometry will define the Mass-Luminosity relation. HST Cal. WS: July 21-23, 2010

  30. Gaia (15 mag) Kinematics: The Future SIM (18 mag) Distances 1% 10% SIM 2.5 kpc 25 kpc Gaia 0.4 kpc 4 kpc Hipparcos 0.01 kpc 0.1 kpc Proper Motions: SIM ~ 2.5 uas/yr Gaia ~ 11 uas/yr Hipparcos ~ 1 mas/yr Gaia and SIM will define the kinematical structure of the Galaxy. HST Cal. WS: July 21-23, 2010

  31. Local Group members • Beyond the merging satellite galaxies • Note that all of the proper motions are predicted to be large in the context of SIM and Gaia accuracies • 3D velocities of the LG members will provide mass estimates of the LG and dark matter Gaia SIM HST Cal. WS: July 21-23, 2010

  32. Summary • The potential for Astrometry to contribute to science is greater than at any time in history! • A desperate need exists to train young scientists in Astrometry to make the most of this exciting future. • There is a trend, especially in the US, for diminishing support for Astrometry. • We need to convince universities, observatories and astronomical institutes to support the education of Astrometrists (and to hire them!!) HST Cal. WS: July 21-23, 2010

  33. HST Cal. WS: July 21-23, 2010

  34. UCAC3: U.S. Naval Observatory CCD Astrograph Catalog • UCAC3 is a compiled, all-sky star catalog of 100 million stars • 8-inch USNO astrograph: south from CTIO, north from USNO Flagstaff • Magnitude range 9 < R < 16 • Wavelength range 670 to 750 nm • Positional errors: 15 to 20 mas for 10 < R < 14 • Photometric data: SuperCosmos and 2MASS • Proper motions: • bright stars are based on about 140 catalogs, including Hipparcos and Tycho, as well as all catalogs used for the Tycho-2 proper motion construction • faint stars are based on a re-reduction of early epoch SPM data (-90 to -10 deg Dec) plus Schmidt plate data from the SuperCosmos project • Zacharias, et al 2009 HST Cal. WS: July 21-23, 2010

  35. URAT: USNO Robotic Astrometric Telescope • URAT successor to the UCAC • Same lens as the UCAC, but four 110 megapixel CCD "superchips" (shown right) in a mosaic to cover 28 square degrees/exposure. • Magnitude range 9 R < 17.5 • Wavelength range 670 to 750 nm • All sky coverage to start in Flagstaff and then move to CTIO • First light expected in 2010 in Washington HST Cal. WS: July 21-23, 2010

  36. SPM4: Yale/San Juan Southern Proper Motion Catalog • 47-year collaboration between the National University of San Juan, Argentina and the Yale Southern Observatory • 103,319,647 stars and galaxies south of -20 degrees declination. • roughly complete to V=17.5 (all are contained in 2MASS) • precision of its positions: 30 to 150 mas • precision of absolute proper motions: 2 to 10 mas/yr • blue and visual passband photometry + 2MASS J,H,K HST Cal. WS: July 21-23, 2010

  37. SPM4: Yale/San Juan Southern Proper Motion Catalog SPM density of observations • 47-year collaboration between the National University of San Juan, Argentina and the Yale Southern Observatory • 103,319,647 stars and galaxies south of -20 degrees declination. • roughly complete to V=17.5 (all are contained in 2MASS) • precision of its positions: 30 to 150 mas • precision of absolute proper motions: 2 to 10 mas/yr • blue and visual passband photometry + 2MASS J,H,K • Girard, et al. 2009 SPM4:  < -200; 102.9 million absolute proper motions 85,155 LEDA reference galaxies HST Cal. WS: July 21-23, 2010

  38. USNO-A2 526,280,881 stars measured on PMM Average J2000 position on red and blue POSS plates ACT/Tycho system Monet, et al. 1998 USNO-B 1 billion stars Average J2000 positions and proper motions from 3 colors at 2 epochs Monet, et al. 2003 USNO PMM Measuring Machine at Flagstaff Schmidt Plate Scans - USNO HST Cal. WS: July 21-23, 2010

  39. Schmidt Plate Scans - STScI & Cosmos • GSC 2.3 release of GSC II • 945,592,683 objects measured on STScI PDS machines • GSC 2.3 is a current catalog release extracted from the Guide Star Catalog II database • Positions on ICRF ACT/Tycho • Bucciarelli, et al. 2008 • SuperCOSMOS • 1.9 billion objects • Average J2000 positions and proper motions from 3 colors at 2 epochs • Positions on Tycho2 and ACT • http://surveys.roe.ac.uk/ssa/ SuperCOSMOS scanner Guide Star Automatic Measuring MAchine HST Cal. WS: July 21-23, 2010

  40. 280 million stars - whole sky Mag range 12 < B < 19 mag Zero-point of the absolute pms uses about 1.45 million galaxies from 2MASS, about 1 mas/yr Systematic errors still exist that are a function of magnitude. Scatter of formal proper motions for the DR5 quasars versus RA and Dec. Proper motion accuracy: 3-4 mas/yr North pm accuracy: 3 mas/yr South pm accuracy: 7 mas/yr Federov, et al. 2009 XPM: 2MASS - USNO-A2.0 HST Cal. WS: July 21-23, 2010

  41. Large-area, deep photometric surveys Carried out on small aperture telescopes for extragalactic studies, but very useful for astrometry: 2MASS (1.3 m), SDSS (2.5 m), INT-WFS (2.5 m) also finding lists for many other surveys, e.g. SPM4. 2MASS (Cutri et al. 2003) HST Cal. WS: July 21-23, 2010

  42. SDSS 2.5-m at Apache Point • SDSS-I/II contains 25% of sky and includes more than 350 million objects • The 300 square degree Southern Equatorial Stripe was scanned more than 20 times in SDSS-I and more than 40 times in the SDSS-II supernova survey. • SDSS DR7: The final data set also includes spectra of 930,000 galaxies, 120,000 quasars, and 460,000 stars. SDSS photometry: streams in the halo. K. Johnston, J. Bullock HST Cal. WS: July 21-23, 2010

  43. SDSS-Based Proper Motions • SDSS-USNO-B • Serious local systematic errors corrected using QSOs. • Covers about 3000 square degrees, i.e. the DR1 release of SDSS. • Typical proper-motion errors between SDSS-SDSS and USNO-B are reduced by 20-30%; the systematic differences are much smaller. • Sigma pm about 3.5 mas/yr. • Munn, et al. AJ 127, 3034, 2004 & AJ 136, 895, 2008 • SDSS-Flagstaff 1.3-m telescope • Covers about 3000 square degrees to date to r = 21 mag. • Proper motion accuracy about 20-30 mas/yr with a 5-year baseline. • Munn, et al. AAS 215, 45202, 2009 • SDSS-SDSS proper motions • 300 square degree Southern Equatorial Stripe was scanned more than 20 times in SDSS-I and more than 40 times in the SDSS-II supernova survey. HST Cal. WS: July 21-23, 2010

  44. Pan-STARRS 1.8-m Sky Survey • Pan-STARRS will survey the whole sky to 24th magnitude every few days • Primary purpose is to detect potentially hazardous objects and to study the minor bodies in the Solar System. • Wide-field, repetitive nature of the Pan-STARRS observations makes them ideal for determination of proper motions. • Comparison with existing catalogs • Pan-STARRS repeat observations for high proper-motion objects • PS1, first of 4 planned telescopes had first light on May 13, 2010. http://pan-starrs.ifa.hawaii.edu/ HST Cal. WS: July 21-23, 2010

  45. SkyMapper - ANU 1.35-m survey telescope • 1.35-m survey telescope under construction by the Australian National Univ. • Designed to carry out the Stromlo Southern Sky Survey (S3), a multi-color, multi-epoch survey of the southern sky analogous to the Sloan Digital Sky Survey. • 20,000 sq. deg. South of equator. • SDSS uvgriz bandpasses to mag 21. • Astrometry to 50 mas. http://msowww.anu.edu.au/skymapper/ HST Cal. WS: July 21-23, 2010

  46. Large Synoptic Survey Telescope 8.4-m primary, 6.7-m effective aperture • First light planned for 2015 • Ten-year imaging survey over 20,000 square degrees south of +15 deg. Each pointing will be imaged 1000 times with fifteen second exposures in six broad bands from 0.35 to 1.1 microns, to a total point-source depth of r~27.5. • Proper motions from observations in Chile over a 10-yr period. • Designed to have Gaia parallax accuracy at r = 20.5 mag and to go 4 mag fainter than Gaia • Required accuracy: • Parallax accuracy of 1 mas at r = 22.4; • Parallax accuracy of 6 mas for red stars with 10 sigma y-band detections; • Proper motion accuracy of 0.2 mas/yr at r = 20.5. • Projected accuracy at r = 24.2 mag • Parallax accuracy: 3 mas • Proper motion accuracy 1 mas/yr at r = 15. • http://www.lsst.org/lsst HST Cal. WS: July 21-23, 2010

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