Program Number | Principal Investigator | Program Title |
---|---|---|
13297 | Giampaolo Piotto, Universita degli Studi di Padova | The HST Legacy Survey of Galactic Globular Clusters: Shedding UV Light on Their Populations and Formation |
13305 | Carolin Villforth, University of St. Andrews | Do mergers matter? Testing AGN triggering mechanisms from Seyferts to Quasars |
13313 | Mederic Boquien, University of Cambridge | Determining attenuation laws down to the Lyman break in z~0.3 galaxies |
13315 | Marc W. Buie, Southwest Research Institute | Pluto Satellite Orbits in Support of New Horizons |
13327 | Eileen T Meyer, Space Telescope Science Institute | Proper Motions at 500 Mpc: Measuring Superluminal motions in Optical Jets with HST |
13330 | Bradley M Peterson, The Ohio State University | Mapping the AGN Broad Line Region by Reverberation |
13332 | Seth Redfield, Wesleyan University | A SNAP Survey of the Local Interstellar Medium: New NUV Observations of Stars with Archived FUV Observations |
13344 | Adam Riess, The Johns Hopkins University | A 1% Measurement of the Distance Scale with Perpendicular Spatial Scanning |
13352 | Matthew A. Malkan, University of California - Los Angeles | WFC3 Infrared Spectroscopic Parallel Survey WISP: A Survey of Star Formation Across Cosmic Time |
13396 | Sarah V. Badman, Lancaster University | Dual views of Saturn's UV aurora: revealing magnetospheric dynamics |
13410 | Cristina Pallanca, Universita di Bologna | COSMIC-LAB: a BSS orbiting a NS? The companion to the supermassive NS in NGC6440. |
13412 | Tim Schrabback, Universitat Bonn, Argelander Institute for Astronomy | An ACS Snapshot Survey of the Most Massive Distant Galaxy Clusters in the South Pole Telescope Sunyaev-Zel'dovich Survey |
13444 | Bart P. Wakker, University of Wisconsin - Madison | Constraining the size of intergalactic clouds with QSO pairs |
13451 | Frederick Hamann, University of Florida | A Study of PG Quasar-Driven Outflows with COS |
13459 | Tommaso L. Treu, University of California - Santa Barbara | The Grism Lens-Amplified Survey from Space {GLASS} |
13462 | Brian E. Wood, Naval Research Laboratory | Tracking the Winds of Red Giants from the Star to the ISM |
13463 | Kailash C. Sahu, Space Telescope Science Institute | Detecting and Measuring the Masses of Isolated Black Holes and Neutron Stars through Astrometric Microlensing |
13482 | Britt Lundgren, University of Wisconsin - Madison | The Evolving Gas Content of Galaxy Halos: A Complete Census of MgII Absorption Line Host Galaxies at 0.7 < z < 2.5 |
13491 | Todd Tripp, University of Massachusetts - Amherst | Directly Probing >10^6 K Gas in Lyman Limit Absorbers at z > 2 |
13495 | Jennifer Lotz, Space Telescope Science Institute | HST Frontier Fields - Observations of Abell 2744 |
13517 | Matthew A. Malkan, University of California - Los Angeles | WFC3 Infrared Spectroscopic Parallel Survey WISP: A Survey of Star Formation Across Cosmic Time |
13632 | John T. Clarke, Boston University | Seasonal Dependence of the Escape of Martian Water |
GO 13344: A 1% Measurement of the Distance Scale with Perpendicular Spatial Scanning
HST WFPC2 image of NGC 4639, one of the Cepheid-rich spiral galaxies used to calibrate SNe Ia |
The cosmic distance scale and dark energy are two key issues in modern astrophysics, and HST has played a vital role in probing both. On the one hand, HST has been involved in cosmic distance measurements since its inception, largely through the H0 Key Project, which used WFPC2 to identify and photometer Cepheids in 31 spiral galaxies at distances from 60 to 400 Mpc. On the other, HST is the prime instrument for investigating cosmic acceleration by searching for and following Type Ia supernovae at moderate and high redshift. These two cosmological parameters are directly related, and recent years have seen renewed interest in improving the accuracy of H0 with the realization that such measurements, when coupled with the improved constraints from the Cosmic Microwave Background, provide important constraints on cosmic acceleration and the nature of Dark Energy. Previous HST programs have focused on identifying and measuring light curves for cepheids in external galaxies (eg GO 10802 , GO 11570 ) or quantifying the effects of variations in intrinsic stellar parameters, such as metallicity (eg GO 10918 , GO 11297 ). The present program focuses on the Galactic Cepheids that form the foundation for the whole distance ladder, employing a revived version of an old technique to determine accurate astrometry, and hence trigonometric parallaxes and reliable distances. The technique is drift-scanning - tracking HST during the observation so that stars form trails on the detector. This mode of observations was available in the early years of HST's operations, and has been revived primarily as a means of obtaing high signal-to-noise grism spectroscolpic data of stars hosting transiting exoplanets. However, the same technique can be used in imaging mode, and the extended trails allow multiple measurements of position differences for stars in the field. The net result is a significant improvement in the relative precision of the final astrometry. The present program, a continuation of Cycle 20 program GO 12879, targets 11 Galactic cepheids and aims for astrometric accuracies of 20 micro-arcseconds. |
GO 13444: Constraining the size of intergalactic clouds with QSO pairs
GO 13495: HST Frontier Fields - Observations of Abell 2744
GO 13632: Seasonal Dependence of the Escape of Martian Water
HST images of Mars oppositions |
Mars lies at an average distance of 228 million kilometres, or 1.52 AU, from the Sun, and has an orbital period of 687 days. As one of earth's nearest neighbours, it has long attracted extensive attention and has been the target of more than 40 missions since the initial fly-by attempts by the USSR in the early 1960s ( see full list ). Mars currently hosts four orbiters and four landers, and the most recent mission, MAVEN, was launched in November 2013 and will arrive at Mars in September of this year. MAVEN's prime mission is to probe the structure and composition of Mars' upper atmosphere. With a mass only just over 10% that of the Earth, Mars has long since lost the atmosphere that permitted liquid water to exist on the surface, but there is a residual very low density component, evident in the sky coloration seen by the landers. HST cannot observe Mars on Maven's arrivial. Howeverf, in preparation for the visit, the current program aims to use the ACS Solar Blind Camera and the Space Telescope Imaging Spectrograph (STIS) to obtain UV imaging and spectra to measure the distribution of ocygen and hydrogen in the outer atmosphere. These observations will sample the Mars atmosphere during a different seasonal phase, extending the in-situ coverage provided by Maven. |