This week on HST


HST Programs: January 12 - January 18, 2015

Program Number Principal Investigator Program Title
13346 Thomas R. Ayres, University of Colorado at Boulder Advanced Spectral Library II: Hot Stars
13390 Nathan Smith, University of Arizona A Time-Lapse Movie of the Kinematics Across the Carina Nebula with ACS
13391 Nathan Smith, University of Arizona WFC3-IR Imaging of Dense, Embedded Outflows from Intermediate-Mass Protostars in Carina
13395 Theodore R. Gull, NASA Goddard Space Flight Center Constraining the evolutionary state of the hot, massive companion star and the wind-wind collision region in Eta Carinae
13419 John Bally, University of Colorado at Boulder The First Ultraviolet Survey of Orion Nebula's Protoplanetary Disks and Outflows
13459 Tommaso L. Treu, University of California - Los Angeles The Grism Lens-Amplified Survey from Space {GLASS}
13517 Matthew A. Malkan, University of California - Los Angeles WFC3 Infrared Spectroscopic Parallel Survey WISP: A Survey of Star Formation Across Cosmic Time
13643 Gaspard Duchene, University of California - Berkeley Imaging the tenuous dusty atmosphere of edge-on protoplanetary disks
13644 Xiaohui Fan, University of Arizona CIII] Emission in z=5.7 Galaxies: A Pathfinder for Galaxy Spectroscopy in the Reionization Era
13657 Jeyhan Kartaltepe, National Optical Astronomy Observatory, AURA Probing the Most Luminous Galaxies in the Universe at the Peak of Galaxy Assembly
13664 Susan D. Benecchi, Planetary Science Institute Origin and Composition of the Ultra-Red Kuiper Belt Objects
13677 Saul Perlmutter, University of California - Berkeley See Change: Testing time-varying dark energy with z>1 supernovae and their massive cluster hosts
13678 Adam Riess, The Johns Hopkins University The Fifth and Final Epoch
13679 Lorenz Roth, Royal Institute of Technology Europa's Water Vapor Plumes: Systematically Constraining their Abundance and Variability
13685 Danny Steeghs, The University of Warwick Emission line imaging of the bipolar shell in the Helium Nova V445 Puppis
13686 Adam Riess, The Johns Hopkins University The Longest Period Cepheids, a bridge to the Hubble Constant
13695 Benne W. Holwerda, Sterrewacht Leiden STarlight Absorption Reduction through a Survey of Multiple Occulting Galaxies (STARSMOG)
13703 Lida Oskinova, Universitat Potsdam The donor star winds in High-Mass X-ray Binaries
13733 Celine Peroux, Laboratoire d'Astrophysique de Marseille The Stellar Continuum Light from Damped Lyman-alpha Absorber Galaxies Detected with Integral Field Spectroscopy
13742 Jonathan Charles Tan, University of Florida Kinematics of a Massive Star Cluster in Formation
13743 David Thilker, The Johns Hopkins University The Controversial Nature of the Diffuse UV Emission in Galaxies: Exploring NGC300
13754 Jeremy J. Drake, Smithsonian Institution Astrophysical Observatory The first mass and angular momentum loss measurements for a CV-like binary
13759 Juan P. Madrid, Gemini Observatory, Southern Operations Extreme Variability in the M87 Jet
13760 Derck L. Massa, Space Science Institute Filling the gap --near UV, optical and near IR extinction
13761 Stephan Robert McCandliss, The Johns Hopkins University High efficiency SNAP survey for Lyman alpha emitters at low redshift
13763 S. Thomas Megeath, University of Toledo WFC3 Spectroscopy of Faint Young Companions to Orion Young Stellar Objects
13767 Michele Trenti, University of Cambridge Bright Galaxies at Hubble's Detection Frontier: The redshift z~9-10 BoRG pure-parallel survey
13773 Rupali Chandar, University of Toledo H-alpha LEGUS: Unveiling the Interplay Between Stars, Star Clusters, and Ionized Gas
13790 Steven A. Rodney, The Johns Hopkins University Frontier Field Supernova Search
13812 Jacobo Ebrero, ESA-European Space Astronomy Centre Tomography of the innermost regions of NGC 985
13816 Misty C. Bentz, Georgia State University Research Foundation High-Resolution Imaging of Active Galaxies with Direct Black Hole Mass Measurements
13829 William B. Sparks, Space Telescope Science Institute The ice plumes of Europa
13846 Todd Tripp, University of Massachusetts - Amherst The COS Absorption Survey of Baryon Harbors (CASBaH): Probing the Circumgalactic Media of Galaxies from z = 0 to z = 1.5
13865 David Jewitt, University of California - Los Angeles Determining the Nature and Origin of Mass Loss from Active Asteroid P/2013 R3
13868 Dale D. Kocevski, Colby College Are Compton-Thick AGN the Missing Link Between Mergers and Black Hole Growth?
13945 Eileen T Meyer, Space Telescope Science Institute Solving the X-ray Origin Problem in Large-scale Jets with Chandra and Fermi Observations

Selected highlights

GO 13390: A Time-Lapse Movie of the Kinematics Across the Carina Nebula with ACS
GO 13395: Constraining the evolutionary state of the hot, massive companion star and the wind-wind collision region in Eta Carinae


Eta Carinae and the Homunculus Nebula as imaged by Hubble
Eta Carinae is one of the brightest and most famous stellar systems in the southern sky. Originally catalogues at fourth magnitude by Edmond Halley in the late 1600s, the star had risen to 2nd magnitude by 1730, fading back to 4th magnitude by the end of the century. In the 1800s the star underwent an even more spectacular outburst, rivalling Sirius at magnitude -0.8 by 1843, but fading below naked eye brightness to below 8th magnitude by 1875. In the 20th century the system brightened to just below 6th magnitude from ~1940 to 1997, and then sharply brightened to 5th magnitude by 1999. Detailed observations from ground and space through the last century have identified the system as a massive binary, with a ~30 solar mass hot supergiant orbitting a ~150 solar mass luminous blue variable. The system is shrouded in extensive clouds of dust and gas produced by mass loss from both stars. Eta Carinae has been studied intensely by Hubble throughout its lifetime, revealing fine detail in the central nebular structure. In particular, the inner structure of the nebula was studied in detail by the Advanced Camera for Surveys in Cycles 13 and 14; program GO 13390 is using the revitalised ACS to obtain new observations and probe how structure has changed over the past decade. Program GO 13395 is using the Space Telescope Imaging Spectrograph to investigate the properties of the stellar winds, particularly the interaction between the winds generated by the two components. At the same time, observations will probe the nature of the hidden secondary star, which is thought to be the prime source of far-UV radiation and X-ray emission.

GO 13677: See Change: Testing time-varying dark energy with z>1 supernovae and their massive cluster hosts


HST/ACS images of a supernova in a galazy at z=1.2
The last few years of the twentieth century saw a revolution in cosmology, with the measurement of the acceleration term in expansion at high redshifts and the identification of dark energy as a major cosmological component. The overall significance of this result has been recognised through the award of the Nobel prize and, most recently, the Fundamental Physics Breakthrough Prize to Perlmutter, Riess and Schmidt and their respective teams. Type Ia supernovae are the prime yardstick for measuring the rate of expansion at moderate and high redshifts. The seminal work in this field was carried out with ground-based telescopes, but Hubble offers almost the only way of obtaining reliable post-maximum photometry of these objects to determine the full shape of the light curve. Many previous HST supernovae programs have concentrated on field galaxies, but applying appropriate corrections for in situ reddening by dust remains an issue in these systems, while the overall SNe detection rates are relatively low at high redshifts. The present program takes a different tack, and aims to minimise the uncertainties by searching for supernovae in massive, high-redshift clusters. The expectation is that the majority of detections lie within dust-poor elliptical galaxies; moreover, supernova rates may be higher. The program will obtain ACS observations of ten of the most massive galaxy clusters lying at redshifts 1.1 < z < 1.75.

GO 13679: Europa's Water Vapor Plumes: Systematically Constraining their Abundance and Variability
GO GO 13829: The ice plumes of Europa


The HST imaging of a potential water plume around Europa's south pole superimposed on an image of the satellite
Europa is the smallest, and the most intriguing, of the four Galilean satellites of Jupiter. With a diameter of 3139 km, Europa is almost twice the size of Earth's moon and significantly larger than Mercury. In 1957, Gerard Kuiper commented that both infrared spectroscopy and the optical colours and albedo suggested that Jovian satellite II (Europa) is covered "by H2O snow". Images taken by the Voyager space probes in the late 1970s (see left) reveal a smooth surface, with only a handful of craters larger than a few kilometres. These features are consistent with a relatively young, icy surface. Subsequent detailed investigations by the Galileo satellite strongly suggest that a substantial body of liquid water, heated by tidal friction, underlies a 5 to 50 km thick icy crust. The presence of this subterranean (subglacial?) ocean clearly makes Europa one of the two most interesting astrobiology targets in the Solar System. Most recently, analysis of observations taken by the Space Telescope imaging Spectrograph (STIS) on Hubble indicated the presence of an extended cloud of Lyman-alpha emission near the polar regions while Europa was furthest in its orbit from Jupiter, strongly suggesting that Europa's oceans may be vaporising into space.Follow-up observations on two further occasions earlier in 2014 failed to detect any emission, suggesting that the emission is either sporadic or periodic; in the latter case, the emission might be related to the location of Europa within its orbit and the consequent tidal strain imposed by Jupiter. The two programs cited here follow up on these observatons. GO 13679 is conducting a methodical series of observatons designed to image Europa at a progressive series of orbital locations. This program uses STIS to search for H and O auroral emissions at UV wavelengths and will aim to map the distribution of emission at different phases of the Europan orbit.. GO 13829 is using UV imaging and spectroscopy with the ACS Solar Blind Camera is searching for fluorescence, with the majority ofthe observations will be taken while Europa is in eclipse. Those observations will be matched against reference data taken out of eclipse.

GO 13790: Frontier Field Supernova Search


Finding chart for the multiply imaged supernova, SN Refsdal, discovered in November 2014 in cluster MACJ1149
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. Hubble is currently undertaking deep imaging observations of up to 6 galaxy clusters as part of the Frontier Fields Director's Time program (GO 13495/13496). Those observations have provided a basis for several synergistic programs. The present program is using the Frontier Field observations to search for supernovae at high redshifts, z> 1.5, aiming to set further constraints on dark energy and probing the frequency of supernovae as a function of redshift, the delay time and hence the likely progenitors. Recent observations of the fourth cluster, MACSJ1149.5+2223, resulted in the detection of a particularly unusual object - multiple lensed images of a supernova in a redshift z=1.49 galaxy that is itself multiply lensed. Each of those images results from light following a different path due to the gravitational potential of the foreground cluster and galaxies. The persent program is obtaining follow-up observations to monitor the light-curves of each component, hence determining the time-delay for each light path. Those measured delays can be matched against the predictions of gravitational lensing models. Moreover, since the galaxy itself has multiple images it is possible that future observations may detect images of the supernova in other components. Thus, this supernova can (perhaps even will) be discovered more than once - and might even be predicted.

Past weeks:
page by Neill Reid, updated 11/11/2014
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