This week on HST

HST Programs: December 25 - December 31 2017

Program Number Principal Investigator Program Title
14610 Julianne Dalcanton, University of Washington A Legacy Imaging Survey of M33.
14635 Yuri I. Izotov, Ukrainian National Academy of Sciences, MAO Lyman continuum leaking in luminous compact star-forming galaxies
14640 John Sebastian Pineda, University of Colorado at Boulder Investigating the FUV Emission of Young M dwarfs with FUMES: the Far Ultraviolet M-dwarf Evolution Survey
14682 Bjorn Benneke, Universite de Montreal A Search for Methane, Ammonia, and Water on Two Habitable Zone Super-Earths
14697 Bradley M Peterson, The Ohio State University A Cepheid Distance to NGC 4051
14716 Francesca Annibali, INAF, Osservatorio Astronomico di Bologna DDO 68: A flea with smaller fleas that on him prey
14769 Sangmo Tony Sohn, Space Telescope Science Institute Proper Motions of Two Local Prototype Dwarf Elliptical Galaxies NGC 147 and NGC 185
14840 Andrea Bellini, Space Telescope Science Institute Schedule Gap Pilot
14843 Laura Kreidberg, Harvard University Clouds in the Forecast? A Joint Spitzer and HST Investigation of Clouds and Hazes for Two Exo-Neptunes
14924 Anil C. Seth, University of Utah Increasing Diversity in Galaxies with Black Hole Mass Measurements
15073 Boris T. Gaensicke, The University of Warwick Extreme evolved solar systems (EESS)
15097 Dolon Bhattacharyya, Boston University Imaging the Extended Hot Hydrogen Exosphere at Mars to Determine the Water Escape Rate
15098 Dolon Bhattacharyya, Boston University Calibrating ACS-SBC Using STIS at Lyman Alpha (121.567 nm)
15099 John P Chisholm, Observatoire de Geneve Do galactic outflows shape the stellar mass-metallicity relationship?
15123 Aaron J. Barth, University of California - Irvine Probing the accretion flow and emission-line regions of M81, the nearest broad-lined low-luminosity AGN
15133 Peter Erwin, Max-Planck-Institut fur extraterrestrische Physik Solving the Mystery of Galaxy Bulges and Bulge Substructure
15140 Ragnhild Lunnan, Stockholm University Resolving the Connection Between Superluminous Supernovae and Star Formation in Dwarf Galaxies
15145 Adam Riess, The Johns Hopkins University The Hubble Constant to 1%: Physics beyond LambdaCDM
15162 Peter Blanchard, Harvard University Constraining the Late-Time Light Curve Behavior of Three Diverse Superluminous Supernovae
15166 Alex V. Filippenko, University of California - Berkeley Continuing a Snapshot Survey of the Sites of Recent, Nearby Supernovae: Cycles 25 & 26
15170 Michael D. Gregg, University of California - Davis Snapshot Survey of the Globular Cluster Populations of Isolated Early Type Galaxies
15201 Clemence Fontanive, Royal Observatory Edinburgh Looking for the Coldest Atmospheres: a Search for Planetary Mass Companions around T and Y Brown Dwarfs
15208 Raghvendra Sahai, Jet Propulsion Laboratory Star-Formation in Free-Floating Evaporating Gaseous Globules
15238 Adam L. Kraus, University of Texas at Austin The IMF to Planetary Masses Across the Milky Way
15242 Lucia Marchetti, Open University SNAPshot observations of the largest sample of lensed candidates in the Equatorial and Southern Sky identified with Herschel
15265 John Blakeslee, NRC Herzberg Institute of Astrophysics MASSIVE+: The Growth Histories of MASSIVE Survey Galaxies from their Globular Cluster Colors
15303 Chris D'Andrea, University of Pennsylvania Revealing the Environmental Dependence in Superluminous Supernovae Diversity
15328 Jessica Agarwal, Max Planck Institute for Solar System Research Orbital period and formation process of the exceptional binary asteroid system 288P
15344 David Jewitt, University of California - Los Angeles Centaurs and Activity Beyond the Water Sublimation Zone
15349 Andrew James Levan, The University of Warwick From the longest GRBs to the brightest supernovae
15350 Walter Peter Maksym, Smithsonian Institution Astrophysical Observatory Resolved BPT Mapping of Nearby AGN
15355 Nao Suzuki, Institute for Physics and Mathematics of the Universe Perfect Blackbody Spectra for JWST and Next Generation UV-Opt-IR Standard Star Network
15364 Andrea Bellini, Space Telescope Science Institute Extended F814W Schedule Gap Pilot
15413 Edward M. Cackett, Wayne State University Accretion disk reverberation mapping of the high Eddington rate Seyfert 1 Mrk 110

Selected highlights

GO 14610: A Legacy Imaging Survey of M33

M33, the Triangulum Galaxy (Subaru imaging)
Messier 33, or the Triangulum galaxy, is the smallest of the three spiral galaaxies in the Local Group. Lying at a distance of ~800 kpc from the Milky Way, the system may be a satellite of the Andromeda spiral, and certainly appears to have experienced past interactions. With a mass less than half that of the Milky Way, the galaxy has a small, distinct bulge, no bar and extensive star formation regions forming spiral structure. The proximity to the Milky Way means that Hubble can resolve individual stars, albeit limited to relatively high luminosities. The present program aims to build on that capability by mapping aproximately one-third of the system. Wide Field Camnera 3 and the Advanced Camera for Surveys will be used in parallel to image 54 fields, obtaining multi-band data from the near-UV (F275W filter) through the U, B and I bands (F336W, F475W, F814W) to the near-infarred (F110W and F160W). Those data will enable investigations of the initial mass function for luminous stars; trace the detailed star formation and recent history as a function of location within the galaxy; map the dust distribution; and allow for the detection of star clusters. This dataset will complement the extensive survey of the Andromeda spiral conducted via the PHAT survey.

GO 14697: A Cepheid Distance to NGC 4051

The spiral galaxy, NGC 4051
Cepheid variable stars have been the prime extragalactic distance indicator since Henrietta Leavitt's discovery of the period-luminosity relation described by Cepheids in the Small Magellanic Cloud. It was Hubble's identification of Cepheids in NGC 6822 that finally established that at least some nebulae were island universes. Cepheids and the extragalactic distance scale figure largely in HST's history, notably through the Hubble Constant Program, one of the initial Key Projects. HST has since observed Cepheids in more than 30 galaxies. The present program aims to extend observations to the Seyfert galaxy, NGC 4051, a near-face-on spiral lying at a distance of 9-18 Mpc from the Milky Way. NGC 4051 is one of the best studied Seyferts, having been the target of extensive reverberatikon mapping campaign designed to probe the detailed velocity structure of the ionised gas near the central black hole. This program will use multi-epoch imaging with the WFC3-UVIS and WFC3-IR cameras to identify and monitor Cepheid variables in the system, using the photometric measurements to determine the distance and better constrain the central gas accretion rate. These observations will be coupled with ground-based spatially-resolved spectroscopy of the nuclear regions to determine the mass of the central black hole.

GO 15073: Extreme Evolved Solar Systems

Artist's impression of a comet spiralling in to the white dwarf variable, G29-38
During the 1980s, one of the techniques used to search for brown dwarfs was to obtain near-infrared photometry of white dwarf stars, searching for the infrared excess due to these cool companions. In 1988, Ben Zuckerman and Eric Becklin detected just this kind of excess around the DA white dwarfs, G29-38. However, follow-up observations showed that the excess peaked at longer wavelengths than would be expected for a white dwarf; rather, G 29-38 is surrounded by a dusty disk. Given the orbital lifetimes, those dust particles must be regularly replenished, presumably from rocky remnants of a solar system. G 29-38 stood as a lone prototype for almost 2 decades until a handful of other dusty white dwarfs were identified from Spitzer observations. In subsequent years, a significant number of DA white dwarfs have been found to exhibit narrow metallic absorption lines in their spectra. Those lines are generally attributed to "pollution" of the white dwarf atmospheres. Given that the diffusion time for metals within the atmospheres is short (tens to hundreds of years), the only reasonable means of maintaining such lines in ~20% of the DA population is to envisage continuous accretion from a surrounding debris disk. The Cosmic Origins Spectrograph (COS) is an ideal instrument for probing the abundance of trace elements in white dwarfs atmospheres: more than 70 systems have been observed, with detection rates running at around 50%. The present program is using COS to refine the statistics for such systems, focusing primarily on higher-mass whiite dwarfs that are likely to be the remnants of internediate-mass main-sequence stars.

GO 15328: Orbital period and formation process of the exceptional binary asteroid system 288P

The multiple nuclei of the main belt comet P/2013 R3 as imaged by Hubble in late 2013 and 2014
The classical picture evoked by the noun 'asteroid" is of a large, unchanging space rock, silently orbiting the Sun within the main belt, between Mars and Jupiter. Over the last decade, however, observations have shown that this classical picture is, like many, not entirely accurate. A number of asteroids have been discovered that show clear signs of some type of surface activity. Some have been dubbed "main belt comets", including the asteroid Scheila (d ~ 110 km), which was observed to have acquired a halo in October-December 2010; the asteroid 1979 OW7/1996 N2, which exhibited similar behaviour in 1996 and again in 2002; MBC-2013-P5, which has exhibited a spectacular set of dusty tails; and MBC P/2013 R3 (pictured here), which has multiple "nuclei" that are gradually drifting apart at speeds of less than 1 metre/second. The origin of the activity is unclear, and may reflect either the present of volatiles or residual effects from fragmentation. The present observations centre on the asteroid 288P/300163 (also known as 2006 VW139).This system was detected in outburst in 2010/2011, and has been resolved as a binary with near-equal components on a wide, eccentric orbit. The present observations aim to map the orbit in greater detail as the system approaches perigee. The goal is to determine the orbital period and eccentricity to discriminate betwen formation through fission or collisional impact. The system will be imaged at optical wavelengths with Wide Field Camera 3.

Past weeks:
page by Neill Reid, updated 31/8/2017
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