HST this week: 128



This week on HST


HST Programs: May 8 - May 14, 2017

Program Number Principal Investigator Program Title
14181 S Thomas Megeath, University of Toledo A Snapshot WFC3 IR Survey of Spitzer/Hershel-Identified Protostars in Nearby Molecular Clouds
14594 Rich Bielby, Durham Univ. QSAGE: QSO Sightline And Galaxy Evolution
14597 Jay Farihi, University College London An Ultraviolet Spectral Legacy of Polluted White Dwarfs
14606 Brooke Devlin Simmons, University of California - San Diego Secular Black Hole Growth and Feedback in Merger-Free Galaxies
14618 Michael Shara, American Museum of Natural History Ultraviolet Flashers in M87: Rapidly Recurring Novae as SNIa Progenitors
14623 Mike Anderson, Max-Planck-Institut fur Astrophysik A Novel Measurement of Turbulence and Bulk Flows in the Hot Halo of M87
14634 Denis C Grodent, Universite de Liege HST-Juno synergistic approach of Jupiter's magnetosphere and ultraviolet auroras
14637 Knox S. Long, Eureka Scientific Inc. Wide band spectra of nova-like variables: A confrontation of observations with theory
14644 Pieter van Dokkum, Yale University Exploring the extremely low surface brightness sky: distances to 23 newly discovered objects in Dragonfly fields
14652 Benne Willem Holwerda, University of Louisville Research Foundation, Inc. Super-Eight: The brightest z~8 Galaxies
14675 Julia Christine Roman-Duval, Space Telescope Science Institute - ESA Metal Evolution and TrAnsport in the Large Magellanic Cloud (METAL): Probing Dust Evolution in Star Forming Galaxies
14681 Alessandra Aloisi, Space Telescope Science Institute Tracing Galactic Outflows to the Source: Spatially Resolved Feedback in M83 with COS
14694 Stephan Robert McCandliss, The Johns Hopkins University SDSSCGB-46589.1 -- a Lyman Alpha Blob at Low Redshift?
14704 Charlie Conroy, Harvard University A Year in the Whirlpool
14706 Eilat Glikman, Middlebury College Testing the Triggering Mechanism for Luminous, Radio-Quiet Red Quasars in the Clearing Phase: A Comparison to Radio-Loud Red Quasars
14717 Iair Arcavi, University of California - Santa Barbara What is Enhancing the Tidal Disruption Rate of Stars in Post-Starburst Galaxies?
14718 George D. Becker, University of California - Riverside The Metal-Enriched Environments of Galaxies Near Reionization
14734 Nitya Kallivayalil, The University of Virginia Milky Way Cosmology: Laying the Foundation for Full 6-D Dynamical Mapping of the Nearby Universe
14747 Brant Robertson, University of California - Santa Cruz Lyman Continuum Escape Survey (LACES): Detecting Ionizing Radiation from z~3 LAEs with Powerful Optical Lines
14754 Crystal Linn Martin, University of California - Santa Barbara Confronting the 3D Orientation of Galactic Disks in Space: Disk Structure vs. Circumgalactic Gas Flows
14762 Justyn Robert Maund, University of Sheffield A UV census of the sites of core-collapse supernovae
14767 David Kent Sing, University of Exeter The Panchromatic Comparative Exoplanetary Treasury Program
14777 Nahum Arav, Virginia Polytechnic Institute and State University Deciphering Quasar Outflows and Measuring their Contribution to AGN Feedback
14796 Denija Crnojevic, Texas Tech University An extremely asymmetric dwarf satellite distribution around M101
14840 Andrea Bellini, Space Telescope Science Institute Schedule Gap Pilot
14917 Vincent Bourrier, Observatoire de Geneve What is the origin of the UV-absorbing cloud orbiting the iconic star 55 Cnc ?

Selected highlights

GO 14767: The Panchromatic Comparative Exoplanetary Treasury Program


Artist's impression of the GJ 1214 system
The first exoplanet, 51 Peg b, was discovered through radial velocity measurements in 1995. 51 Pegb was followed by a trickle, and then a flood of other discoveries, as astronomers realised that there were other solar systems radically different from our own, where "hot jupiters" led to short-period, high-amplitude velocity variations. Then, in 1999, came the inevitable discovery that one of those hot jupiters. HD 209458b, was in an orbit aligned with our line of sight to the star, resulting in transits. Since that date, the number of known transiting exoplanet systems has grown to more than 100 from ground-based observations, most detected through wide-field photometric surveys, while the high-sensitivity data provided by Kepler has added a further 1000+ confirmed systems and ~2000 additional candidates. Transiting systems not only provide an accurate measure of the planetary radius (at least relative to the parent star), they also provide us with an opportunity to probe the atmospheric composition through spectroscopy during the transit. Hubble has made significant inroads in this area, while Spitzer has contributed measurements of planetary emissivity through observations during and after eclipse. The James Webb Space Telescope has the capability to revolutionise our knowledge in this field through highly sensitiive observations at near and mid-infra red wavelengths. The present program aims to lay the foundation for those programs by using Hubble to compile multiwavelength (UV to near-IR) spectroscopic observations of 20 exoplanets. The targets are all gas giants, ranging from super-jovian masses to neptunian masses. The observations will be obtained with the Space Telescope Imaging Spectrograph and the near-infrared grisms on Wide Field Camera 3.

GO 14734: Milky Way Cosmology: Laying the Foundation for Full 6-D Dynamical Mapping of the Nearby Universe


The low-mass dwarf galaxy, Leo II
The Milky Way, M31 and M33 are the three largest galaxies in the Local Group. That system, however, includes more than 25 other members, with the majority being dwarf spheroidal galaxies that are satellites of either M31 or the Milky Way. Those galaxies have old, evolved stellar populations, and even the most prominent have masses that are less than a few x 107 MSun, or 10-4 that of the Milky Way. All of these galaxies are moving in the potential set by the overall Local Group system, but dominated by M31 and the Milky Way. Determining full space motions for the dwarfs therefore provide a means of constraining that potential. Even though the galaxies, and their brightest stellar constituents, are faint, measuring radial velocity is a relatively straightforward procedure. Deriving tangential motions is not, since the typical proper motions of these systems are a few mas/year at best. The present proposal aims to capitalise on the exceptional resolution and high stability of HST to address this issue. Wide Field Camera 3 and the Advanced Camera for Surveys will be used to obtain first epoch observations of the 32 known dwarf galaxies within 420 kpc. that currently lack such data. These observations will lay the foundation for future observations with both HST and future missions, including JWST and WFIRST.

GO 14762: A UV census of the sites of core-collapse supernovae


Chandra X-ray image of G292.0+1.9, a ~3000-year old supernoa remnant
Supernovae are generally believed to originate through two mechanisms: accretion onto a white dwarf in a close binary system, driving the white dwarf above the Chandrasekhar limit; and the implosion of the core of very massive (> 7 solar masses) stars. Both processes result in explosive nucleosythesis that enriches the interstellar medium, with the ejecta forming a rapidly expanding shell. Supernovae are intrinsically rare: Tycho's star (1604) was the last Galactic supernova identified by contemporary astronomers, although the radio remnant Cas A (identiied as 3C 461 in the 1959 Third Cambridge Catalogue of Radio Stars) may have been recorded, if not recognised as unusual, by Flamsteed in 1680. Understanding their progenitors therefore demands that we expand observations to external galaxies. The present program builds on several from previous cycles, and uses HST to obtain high-resolution imaging of the sites of several Type II supernovae in nearby galaxies. By now, the supernova themselves have faded from view, but the HST data can reveal the stellar population in the immediate environs. detailed analysis of the colour magnitude diagrams can probe the local environment,the likely age of the star forming regions, and hence set limits of the progenitor mass.

GO 14917: What is the origin of the UV-absorbing cloud orbiting the iconic star 55 Cnc?


Artist's impression of atmospheric stripping from an exoplanet
The first exoplanet, 51 Peg b, was discovered through radial velocity measurements in 1995. 51 Pegb was followed by a trickle, and then a flood of other discoveries, as astronomers realised that there were other solar systems radically different from our own, where "hot jupiters" led to short-period, high-amplitude velocity variations. Then, in 1999, came the inevitable discovery that one of those hot jupiters. HD 209458b, was in an orbit aligned with our line of sight to the star, resulting in transits. Since that date, the number of known transiting exoplanet systems has grown to more than 3000, most detected through wide-field photometric surveys with the Kepler satellite providing the highest sensitivity dataset. Transiting systems are invaluable, since they not only provide unambiguous measurements of mass and diameter, but they also provide an opportunity to probe the atmospheric structure by differencing spectra taken during and between primary secondary transit. The present program focuses on the 55 Cnc system, known to harbour at least five planets ranging in mass from ~8.6 Earth mases masses to 4.2 times the mass of Jupiter and with semi-major axes ranging from 0.016 to 5.47 AU. The innermost planet, 55 Cnc e, is the least massive and the parent star is a late G dwarf at a distance of only 12.3 parsecs.Optical and infrared observations suggest that 55 Cnc e has a dense atmosphere, perhaps generated by magma ocans on the surface. Recent observations indicated strong Lyman alpha absorption curing the transit, possibly stemming from a large hydrogen cloud associated with the planet. The present observations aim to use STIS to map the absorption variation through two transits.

Past weeks:
page by Neill Reid, updated 2 /1/2017
These pages are produced and updated on a best effort basis. Consequently, there may be periods when significant lags develop. we apologise in advance for any inconvenience to the reader.

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