This week on HST

HST Programs: September 5 - September 11, 2016

Program Number Principal Investigator Program Title
13761 Stephan Robert McCandliss, The Johns Hopkins University High efficiency SNAP survey for Lyman alpha emitters at low redshift
14038 Jennifer Lotz, Space Telescope Science Institute HST Frontier Fields - Observations of Abell 370
14072 Martha L. Boyer, Space Telescope Science Institute The Evolution of Metal-rich Asymptotic Giant Branch Stars
14076 Boris T. Gaensicke, The University of Warwick An HST legacy ultraviolet spectroscopic survey of the 13pc white dwarf sample
14086 Jay Strader, Michigan State University Dynamical Confirmation of a Stellar-mass Black Hole in the Globular Cluster M62
14096 Dan Coe, Space Telescope Science Institute - ESA RELICS: Reionization Lensing Cluster Survey
14098 Harald Ebeling, University of Hawaii Beyond MACS: A Snapshot Survey of the Most Massive Clusters of Galaxies at z>0.5
14127 Michele Fumagalli, Durham Univ. First Measurement of the Small Scale Structure of Circumgalactic Gas via Grism Spectra of Close Quasar Pairs
14132 Mark B. Peacock, Michigan State University The spatial distribution of hot stellar populations in M31's globular clusters
14150 Morgan Fraser, University of Cambridge Searching for the disappearance of the progenitor of the unique SN 2009ip
14163 Mickael Rigault, Humboldt Universitat zu Berlin Honing Type Ia Supernovae as Distance Indicators, Exploiting Environmental Bias for H0 and w.
14171 Guangtun Zhu, The Johns Hopkins University Characterizing the Circumgalactic Medium of Luminous Red Galaxies
14178 Matthew A. Malkan, University of California - Los Angeles WFC3 Infrared Spectroscopic Parallel Survey: The WISP Deep Fields
14181 S Thomas Megeath, University of Toledo A Snapshot WFC3 IR Survey of Spitzer/Hershel-Identified Protostars in Nearby Molecular Clouds
14188 Beth Biller, University of Edinburgh, Institute for Astronomy Exometeorology: Characterizing Weather on a Young Free-Floating Planet
14219 John P. Blakeslee, Dominion Astrophysical Observatory Homogeneous Distances and Central Profiles for MASSIVE Survey Galaxies with Supermassive Black Holes
14227 Casey Papovich, Texas A & M University The CANDELS Lyman-alpha Emission At Reionization (CLEAR) Experiment
14251 Amy E. Reines, National Optical Astronomy Observatory, AURA The Structures of Dwarf Galaxies Hosting Massive Black Holes
14268 Nicolas Lehner, University of Notre Dame Project AMIGA: Mapping the Circumgalactic Medium of Andromeda
14340 Alexandre Gallenne, European Southern Observatory - Chile Accurate masses and distances of the binary Cepheids S Mus and SU Cyg
14353 Andrew S. Fruchter, Space Telescope Science Institute The Astrophysics of the Most Energetic Gamma-Ray Bursts
14673 Charles R. Proffitt, Space Telescope Science Institute A Definitive Test of Rotational Mixing in Massive Stars
14676 David J. Sand, Texas Tech University Two New Local Volume Dwarfs Associated with Compact High Velocity Clouds: Distance, Structure and Star Formation History
14677 Tim Schrabback, Universitat Bonn, Argelander Institute for Astronomy Probing the most distant high-mass galaxy clusters from SPT with HST weak lensing observations
14695 S Thomas Megeath, University of Toledo WFC3 Imaging of 24 um Dropout Protostars in Orion
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
14727 Pierre-Alain Duc, Commissariat a l'Energie Atomique (CEA) Probing Super Star Cluster formation in the most favorable environments: the metal-enriched, gas-rich and turbulent collisional ring of NGC 5291
14745 Bettina Posselt, The Pennsylvania State University Is there a substellar companion around the neutron star RX J0806.4-4123?
14773 Thomas M. Brown, Space Telescope Science Institute A Direct Distance to an Ancient Metal-Poor Star Cluster
14781 Chris S. Kochanek, The Ohio State University Ultraviolet Spectroscopic Monitoring of an ASAS-SN Tidal Disruption Event
14790 Jessica Agarwal, Max Planck Institute for Solar System Research Investigating the binary nature of active asteroid 288P/300163

Selected highlights

GO 14038: HST Frontier Fields - Observations of Abell 370

HST observations of the Frontier Fields cluster, Abell 370
The overwhelming majority of galaxies in the universe are found in clusters. As such, these systems offer an important means of tracing the development of large-scale structure through the history of the universe. Moreover, as intense concentrations of mass, galaxy clusters provide highly efficient gravitational lenses, capable of concentrating and magnifying light from background high redshift galaxies to allow detailed spectropic investigations of star formation in the early universe. Hubble imaging has already revealed lensed arcs and detailed sub-structure within a handful of rich clusters. At the same time, the lensing characteristics provide information on the mass distribution within the lensing cluster. The present program builds on the highly successful CLASH program,which used 17-colour ACS/WFC3 images to map 25 galaxy clusters, tracing the mas profile and the dark matter distribution. in addition, the observations identified several lensed galaxies at redshifts that enter the JWST domaine, with the most distant object lying at a redshift z~11, within a few hundred million years of the Big Bang. The Frontier Fields program is a large-scale Director's Discretionary program that capitalises on the latter characteristic by targeting 4-6 strong-lensing galaxy clusters for very deep optical and near-infrared imaging. WFC3 and ACS will be used to observe the clusters, with simultaneous imaging obtained in parallel of a nearby "blank" field. Since the observations need to made at a specific orientation, they are being taken in two sets, ~6 months apart, alternating between detectors. Abell 370 at z=0.375 is the sixth and final target. The present observations will provide the second epoch data, with WFC3-IR covering the cluster and ACS centred on the parallel field. The observations taken this week are the final observations of the three year Frontier Fields campaign.

GO 14086: Dynamical Confirmation of a Stellar-mass Black Hole in the Globular Cluster M62

An HST image of the globular cluster M62
Black holes form when sufficient mass accumulates that gravity overcomes all other forces and results in collapse to a singularity. The existence of black holes, at least supermassive black holes, is no longer in doubt with the measurement of dynamical motions in the central regioins of many galaxies, including our own. The evidence clearly points to many millions of solar masses concentrated within a suffuciently small volume that supermassive black holes are the only option. Theoretically, however, there are also rpedictions of black holes of smaller mass - intermediate black holes, with masses between 100 to 1 million solar masses. These are hypothesised to have formed in a similar manner to the supermassive black holes, but to have formed in sparser environments, where less material was available for the runaway accretion that builds supermassive black holes. Direct evidence for the existence of such systems is still lacking. One of the key set of objects being searched for such evidence is the set of Milky Way globular clusters since those objects are hypothesised as forming in an appropriate environment. The present program focuses on M62, a relatively metal-rich ([Fe/H]=-1.2) cluster at a distance of ~7 kpc from the Sun. Using radio, X-ray and optical obsrevations, the proposers have identified a potential candidate in the cluster. The candidate appears to be in a binary system with a red giant companion, and the proposers aim to use STIS to obtain multi-epoch spectra to verify the mass estimate. If confirmed, this would be the first such object dientified.

GO 14181: A Snapshot WFC3 IR Survey of Spitzer/Hershel-Identified Protostars in Nearby Molecular Clouds

An image of the Orion Nebula superimposed on the 13CO map of Orion A (from this link ).
Giant molecular cloud complexes serve as nurseries for star formation. Deeply embedded in dust and gas, young stars are generally extremely difficult to detect at optical wavelengths. Consequently, these complexes have been subject to extensive scrutiny at near- and mid-infrared wavelengths, initially through ground-based observing campaigns and more recently by the Spitzer and Herschel space missions. Those observations have resulted in the identification of numerous embedded sources, young stellar objects (YSOs) that are still accreting from the surrounding molecular gas .he present proposal aims to follow up on those discoveries by obtaining WFC3-IR SNAPs of candidate protostars in several molecular cloud complexes. These observations will provide an excellent complement to Spitzer and Herschel since, while HST cannot offer either the same areal coverage or sensitivity at mid-infrared wavelegths, the imaging has a resolution close to 0.1 arcsecond, an order of magnitude higher than the Spitzer images. The observations are therefore capable of detecting very faint companions, with luminosities consistent with sub-stellar masses, as well as identifying jets and outflows associated with the star formation process. The present program is using the F160W filter to obtain H-band images and determine the true nature of these objects.

GO 14268: Project AMIGA: Mapping the Circumgalactic Medium of Andromeda

The extent of Andromeda's gaseous halo, as sampled by COS
Galaxy formation, and the overall history of star formation within a galaxy, clearly demands the presence of gas. The detailed evolution therefore depends on how gas is accreted, recycled, circulated through the halo and, perhaps, ejected back into the intergalactic medium. Tracing that evolutionary history is difficult, since gas passes through many different phases, some of which are easier to detect than others. During accretion and, probably, subsequent recycling, the gas is expected to be reside predominantly at high temperatures. The most effective means of detecting such gas is through ultraviolet spectroscopy, where gas within nearby systems can be detected as absorption lines superimposed on the spectra of more distant objects, usually quasars. Extensive observations of galaxies at modest redshift (0.15 < z < 0.35) have shown that material extends to radii of hundreds of kpc, with a total mass in metals that is at least comparable with the mass in the central galaxy. Andromeda, the nearest large spiral to the Milky Way,provides an unparalleled opportunity to probe the detailed structure of the gaseous halo. The present program will target background QSOs along 18 sightlines at radial distances between 25 and 330 kpc. from Andromeda's nucleus. Combined with archival data for 7 other background targets, these data will be sensitive to a wide range of key species OI 1302, CII 1334, SiII 1190, 1193, 1523, SiIII 1206, SiIV 1393,1402, CIV 1548, 1550), probing the composition and ionisation of the halo.

Past weeks:
page by Neill Reid, updated 23/12/2014
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