This week on HST

HST Programs: April 6 - April 12, 2015

Program Number Principal Investigator Program Title
13287 Ori Dosovitz Fox, University of California - Berkeley Late-Time UV Spectroscopic Signatures from Circumstellar Interaction in Type IIn Supernovae
13646 Ryan Foley, University of Illinois at Urbana - Champaign Understanding the Progenitor Systems, Explosion Mechanisms, and Cosmological Utility of Type Ia Supernovae
13648 Ori Dosovitz Fox, University of California - Berkeley Uncovering the Putative B-Star Binary Companion of the SN 1993J Progenitor
13652 Boris T. Gaensicke, The University of Warwick The frequency and chemical composition of rocky planetary debris around young white dwarfs: Plugging the last gaps
13654 Matthew Hayes, Stockholm University Ultraviolet Spectroscopy of the Extended Lyman Alpha Reference Sample
13655 Matthew Hayes, Stockholm University How Lyman alpha bites/beats the dust
13659 Karin Sandstrom, University of California - San Diego A New View of Dust at Low Metallicity: The First Maps of SMC Extinction Curves
13677 Saul Perlmutter, University of California - Berkeley See Change: Testing time-varying dark energy with z>1 supernovae and their massive cluster hosts
13682 Pieter van Dokkum, Yale University Distances and stellar populations of seven low surface brightness galaxies in the field of M101
13691 Wendy L. Freedman, University of Chicago CHP-II: The Carnegie Hubble Program to Measure Ho to 3% Using Population II
13695 Benne W. Holwerda, Sterrewacht Leiden STarlight Absorption Reduction through a Survey of Multiple Occulting Galaxies (STARSMOG)
13728 Steven Kraemer, Catholic University of America Do QSO2s have Narrow Line Region Outflows? Implications for quasar-mode feedback
13737 Benjamin John Shappee, Carnegie Institution of Washington Whimper of a Bang: Documenting the Final Days of the Nearby Type Ia Supernova 2011fe
13740 Daniel Stern, Jet Propulsion Laboratory Clusters Around Radio-Loud AGN: Spectroscopy of Infrared-Selected Galaxy Clusters at z>1.4
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
13767 Michele Trenti, University of Melbourne Bright Galaxies at Hubble's Detection Frontier: The redshift z~9-10 BoRG pure-parallel survey
13774 Sara Ellison, University of Victoria Feeding and feeback: The impact of AGN on the circumgalactic medium.
13776 Michael D. Gregg, University of California - Davis Completing The Next Generation Spectral Library
13790 Steven A. Rodney, The Johns Hopkins University Frontier Field Supernova Search
13792 Rychard Bouwens, Universiteit Leiden A Complete Census of the Bright z~9-10 Galaxies in the CANDELS Data Set
13797 Alex V. Filippenko, University of California - Berkeley Early-Time UV Spectroscopy of Stripped-Envelope Supernovae: A New Window
13802 Kevin Luhman, The Pennsylvania State University Characterizing the Sun's 4th Closest Neighbor and the Coldest Known Brown Dwarf
13820 David Ehrenreich, Observatoire de Geneve Search for an evaporating ocean on the super-Earth HD 97658b
13826 Massimo Robberto, Space Telescope Science Institute The Orion Nebula Cluster as a Paradigm of Star Formation
13852 Rongmon Bordoloi, Space Telescope Science Institute How Galaxy Mergers Affect Their Environment: Mapping the Multiphase Circumgalactic Medium of Close Kinematic Pairs
13865 David Jewitt, University of California - Los Angeles Determining the Nature and Origin of Mass Loss from Active Asteroid P/2013 R3
13866 David Jewitt, University of California - Los Angeles Determining the Nature and Origin of Mass Loss from Active Asteroid P/2013 P5
13947 Julia C. Lee, Smithsonian Institution Astrophysical Observatory An X-ray, UV, and radio probe of the PG 1211+143 inflow-outflow dynamics

Selected highlights

GO 13646: Understanding the Progenitor Systems, Explosion Mechanisms, and Cosmological Utility of Type Ia Supernovae

Supernova 2015F in NGC 2442; image by STan Howerton
Supernovae are the most spectacular form of stellar obituary. Since B2FH, the physical processes underlying their eruptive deaths have been known to play a key role in populating the ISM with metals beyond the iron peak. More recently, these celestial explosions have acquired even greater significance through the use of Type Ia supernovae as distance indicators in mapping the `dark energy' acceleration term of cosmic expansion. However, while there are well-established models for the two main types of supernovae (runaway fusion on the surface of a white dwarf in a binary system for Type Ia, or detonation of the core in Type II), some significant uncertainties remain concerning the physical details of the disruption, and, potentially, the overall uniformity of these events. Consequently, there is potential for systematic bias in the distance estimates. The present program aims to address this issue through detailed observations of a small number of relatively nearby Type Ia Sne, using the Space telescope Imagign Spectrograph to provide spectral coverage over the full UV and visual wavelength ergime. The program aims to pick up the supernovae before maximum, and take spectra at regular (~4 day) intervals, providing detailed coverage of the changing abundances within the SNe ejecta. This is a target of opportunity, and the present set of observations are aimed at SN 2015f in NGC 2442/2443, an active spiral galaxy, also known as the "Meathook", lying at a distance of ~20 Mpc. The supernova was discovered at 13th magnitude in mid-March. The first HST observations were made on March 16th, with subsequent observations through April 12th.

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 13767: Bright Galaxies at Hubble's Detection Frontier: The redshift z~9-10 BoRG pure-parallel survey

The ACS optical/far-red image of the Hubble Ultra Deep Field
Galaxy evolution in the early Universe is a discipline of astronomy that has been transformed by observations with the Hubble Space Telescope. The original Hubble Deep Field, the product of 10 days observation in December 1995 of a single pointing of Wide Field Planetary Camera 2, demonstrated conclusively that galaxy formation was a far from passive process. The images revealed numerous blue disturbed and irregular systems, characteristic of star formation in galaxy collisions and mergers. Building on this initial progam, the Hubble Deep Field South (HDFS) provided matching data for a second southern field, allowing a first assessment of likely effects due to field to field cosmic variance, and the Hubble Ultra-Deep Field (UDF) probed to even fainter magitude with the Advanced Camera for Surveys (ACS). The highest redshift objects found in the UDF have redshifts approaching z~7. Pushing to larger distances, and greater ages, demands observatons at near-infrared wavelengths, as the characteristics signatures of star formation are driven further redward in the spectrum. Wide Field Camera 3, installed in Servicing Mission 4, is well suited to these observations, and a number of programs are in place in Cycle 17 that address these issues. Indeed, WFC3 is employed in pure parallel mode by several programs. These take advantage of other science programs, usually with COS, that involve 2-5 orbit pointings on sources at high galactic latitude. The WFC3 pointing is unplanned, since it depends on the orientation adopted for the prime observations, but 2-5 orbits of IR imaging can reach galaxies at redshifts exceeding z=7 (potentially even z~8) in high latitude fields. The present program builds on similar programs in Cycles 17 and 19, and aims to detect the brightest galaxies at z~9, within 600 Myrs of the Big Bang.

GO 13865: Determining the Nature and Origin of Mass Loss from Active Asteroid P/2013 R3

The multiple nuclei of MBC P/2013 R3 as imaged by Hubble in late 2013 and 2014
The term 'comet" is generally associated with low-mass, volatile-rich solar system objects that spend most of their life at very lage distances from the Sun, plunging only rarely into the inner regions where they acquire extended tails due to outgassing. Sometimes those obejcts are captured into short-period, eccentric orbits, leading to rapid depletion of the volatile content in rapidly-successive perihelion passages. However, recent years have seen growing evidence of another class of cometes exist: comets with near-circular orbits that place them between Mars and Jupiter, within the realm of the Main Belt of asteroids. One of the first candidate main belt comets, as these objects have been dubbed, is the asteroid Scheila. Discovered by the Heidelberg astronomer August Kopff in 1906, and named after an English student with whom he was acquainted, this is one of the larger known asteroids, with a diameter estimated as ~110 km. Early December 2010, Steve Larson (of Arizona's Lunar and Planetary Laboratory) noted that Scheila had sprouted a coma halo in observations taken by the Catalina Sky Survey. An examination of archival images revealed no evidence for activity throughout October and November, but a possible onset on December 3rd. The asteroid 1979 OW7/1996 N2 exhibited similar behaviour in 1996 and again in 2002; the initial outburst was ascribed to a collision, but the second event suggests that the activity is intrinsic rather than externally stimulated. More recently, the Pan-STARRS survey has contributed several objects, including the asteroid 2006 VW139, imaged during an outburst, MBC 2013-P5, which has exhibited a spectacular set of dusty tails, and MBC P/2013 R3, which has multiple "nuclei" that are gradually drifting apart at speeds of less than 1 metre/second. The latter object is probably best explained as the result of rotational break-up. The present monitoring program with Wide-Feld Camera 3 will enable measureemnt of their orbits and, through time-resolved photomtery, determination of the rotation periods of the individual fragments.

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