This week on HST


HST Programs: June 19 - June 25, 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
14618 Michael Shara, American Museum of Natural History Ultraviolet Flashers in M87: Rapidly Recurring Novae as SNIa Progenitors
14627 Susan D. Benecchi, Planetary Science Institute The Lightcurve of New Horizons Encounter TNO 2014 MU69
14633 Kevin France, University of Colorado at Boulder A SNAP UV Spectroscopic Study of Star-Planet Interactions
14635 Yuri I. Izotov, Ukrainian National Academy of Sciences, MAO Lyman continuum leaking in luminous compact star-forming galaxies
14637 Knox S. Long, Eureka Scientific Inc. Wide band spectra of nova-like variables: A confrontation of observations with theory
14658 Eric W. Peng, Peking University Massive Star Clusters and the Origin of Ultra-Diffuse Galaxies
14660 Lorrie Straka, Sterrewacht Leiden Morphology and Orientation of QSO Absorber Host Galaxies at z<1.5 Detected with VLT/MUSE1/st
14668 Alex V. Filippenko, University of California - Berkeley Continuing a Snapshot Survey of the Sites of Recent, Nearby Supernovae: Cycle 24
14674 Robert M. Quimby, San Diego State University Far UV Spectroscopy of Superluminous Supernovae
14677 Tim Schrabback, Universitat Bonn, Argelander Institute for Astronomy Probing the most distant high-mass galaxy clusters from SPT with HST weak lensing observations
14679 Daniel P. Stark, University of Arizona Extremely Metal Poor Galaxies with HST/COS: Completing the Groundwork for JWST
14690 Hans Moritz Guenther, Massachusetts Institute of Technology Identifing the last unkown emission component in the Herbig system HD 163296
14704 Charlie Conroy, Harvard University A Year in the Whirlpool
14707 Philip Louis Massey, Lowell Observatory Searching for the Most Massive Stars in M31 and M33
14719 Philip N. Best, Royal Observatory Edinburgh The detailed properties of star-forming regions at high redshift: a matched-resolution HST-Halpha-ALMA study
14734 Nitya Kallivayalil, The University of Virginia Milky Way Cosmology: Laying the Foundation for Full 6-D Dynamical Mapping of the Nearby Universe
14739 Guilin Liu, University of Science & Technology of China Imaging BALQSO outflows: a critical step in assessing AGN feedback
14747 Brant Robertson, University of California - Santa Cruz Lyman Continuum Escape Survey (LACES): Detecting Ionizing Radiation from z~3 LAEs with Powerful Optical Lines
14748 Aaron Romanowsky, San Jose State University A close-up view of the star formation history of a young ultracompact dwarf
14762 Justyn Robert Maund, University of Sheffield A UV census of the sites of core-collapse supernovae
14764 Tiffany Meshkat, California Institute of Technology Measuring the structure of Fomalhaut's dusty debris belt via a fortuitous stellar occultation
14767 David Kent Sing, University of Exeter The Panchromatic Comparative Exoplanetary Treasury Program
14796 Denija Crnojevic, Texas Tech University An extremely asymmetric dwarf satellite distribution around M101
14811 Laurent Lamy, Observatoire de Paris - Section de Meudon The Grand Finale : probing the origin of Saturn s aurorae with HST observations simultaneous to Cassini polar measurements
14846 Aaron Romanowsky, San Jose State University Ultra-diffuse Galaxies in Clusters and the Field: Masses and Stellar Populations

Selected highlights

GO 14627: The Lightcurve of New Horizons Encounter TNO 2014 MU69


Hubble Space Telescope images of the Pluto system, including the recently discovered moons, P4 and P5
The Kuiper Belt lies beyond the orbit of Neptune, extending from ~30 AU to ~50 AU from the Sun, and includes at least 70,000 objects with diameters exceeding 100 km. Setting aside Pluto, the first trans-Neptunian objects were discovered in the early 1990s. Most are relatively modest in size, with diameters of a few hundred km and photometric properties that suggest an icy composition, similar to Pluto and its main satellite, Charon. In recent years, a handful of substantially larger bodies have been discovered, with diameters of more than 1000 km; indeed, one object, Eris (2003 UB13), is slightly larger than Pluto (2320 km) and 25% more massive. We know the mass for Eris because it has a much lower mass companion, Dysnomia, which orbits Eris with a period of 16 days (see this recent press release ). Pluto itself has at least 5 companions: Charon, which is about 1/7th the mass of Pluto, and the much smaller bodies, Hydra, Nix, P4 and P5 discovered through HST observations within the last few years. The New Horizons Mission was launched on January 19th 2006 with the prime purpose of providing the first detailed examination of Pluto. Following the Pluto fly-by on Bastille day 2015, the program is redirecting the probe towards one or more smaller members of the Kuiper Belt, with the goal of providing a closer look at these icy bodies. Based on Hubble imaging, a suitable prime target has been identified: 2014 MU69, a ~30 km diameter KBO lying ~44 AU from the Sun. The present program is using the wide band-pass F350LP filter on the WFC3-UVIS camera for an intensive monitoring campaign, 24 orbits spaced over 4 days, to map the photometric variations and perhaps determine a rotational period. In addition, New Horizons is expected to take longer-range, monochromatic images of up to 10 other KBOs. The present observations are being used to refine the orbital parameters for the prime target to optimize the New Horizon encounter.

GO 14668: Continuing a Snapshot Survey of the Sites of Recent, Nearby Supernovae - Cycle 24


A recent supernova in M100
Supernovae mark the (spectacular) evolutionary endpoint for a subset of stellar systems. Standard models predict that they originate from massive stars and (probably) close binaries with a compact (WD, neutron star) component, but there are still some questions remaining over whether we fully understand the range of possible progenitors. The last decade has seen the development of a number of large-scale programs, usually using moderate-sized telescopes, that are dedicated to monitoring (relatively nearby galaxies, searching for new supernovae. This program builds on observations taken in several previous cycles, and aims to obtain follow-up multi-waveband images of nearby galaxies, focusing on the sites of recent supernovae. The program concentrates on systems within 20 Mpc of the Milky Way. The observations are taken well after maximum, with the aim of using the unparalleled angular resolution of WFC3 to identify the fading remnant, search for evidence for light echoes,characterise the local stellar population and perhaps determine the nature of the likely progenitor.

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 14811: The Grand Finale : probing the origin of Saturn's aurorae with HST observations simultaneous to Cassini polar measurements

Planetary aurorae are stimulated by the influx of charged particles from the Sun, which travel along magnetic field lines and funnel into the atmosphere near the magnetic poles. Aurorae therefore require that a planet has both a substantial atmosphere and a magnetic field. They are a common phenomenon on Earth, sometimes visible at magnetic latitudes more than 40 degrees from the pole, and have also been seen on Jupiter, Saturn, Uranus and Neptune. Saturn passed through its equinox in August 2009, and in the succeeding years the north pole has tilted more and more towards the Sun. As a consequence, we now have an excellent view of the polar regions. Moreover, the Cassini probe has moved into a polar orbit, that takes it regularly across the auroral regiosn. The present program is using STIS to obtain time-tagged FUV images during those passages, enabling a direct comparison of the large-scale structure with in situ measurements by the Cassini spacecraft.

Past weeks:
page by Neill Reid, updated 2 /1/2017
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