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Hubble Space Telescope
The HubbleObserver Corner for September 2011

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Proposal ID = 12725
Principle Investigator = Harold Weaver, Johns Hopkins University 
     Applied Physics Laboratory
Title = "A Deep Search for Satellites in the Pluto System: Providing 
    Critical, Safety-of-Flight Support to NASA's New Horizons Mission"
Time = Sep 26, 2011 16:55:34 - 17:52:46
Target = Pluto
Instrument = WFC3/F350LP

Background:

A new moon was recently discovered orbiting Pluto (see http://hubblesite.org/newscenter/archive/releases/2011/23/ ). The moon has been temporarily named P4; it takes a while for an official name to be determined. The purpose of this proposal is to better determine the orbit of P4, and to search for even fainter satellites, in particular candidate new moons P5 and P6 which have been tentatively identified. The moons of Pluto are believed to have been formed by a collision between Pluto and another planet-sized object early in the history of the solar system, a process that may have also been similar to how our own moon formed. This is an example of a Director's Discretionary (DD) proposal - generally a time dependent phenomena that cannot be handled in the normal yearly telescope allocation process. The observations are in support of NASA's New Horizons mission to Pluto, with the flyby planned for July 2015.

Paraphrasing from the abstract:

We propose a simple, 9-orbit (3 orbits at each of 3 epochs) DD program with two objectives: (1) as a safety-of-flight issue, perform a deep search (V=25-26) for satellites in the 0.9 arcsec radius region between Pluto and Charon where NASA's New Horizons mission will fly, and (2) confirm or reject the candidate P5 and P6 satellites seen in recent HST imaging, while performing an even deeper search (V=27) for satellites in the region between Charon and Hydra so observations of them can be planned before the New Horizons mission planning is frozen prior to the on-spacecraft rehearsal. Hubble is uniquely qualified to achieve these time-critical objectives, which we hope to achieve before the Pluto system enters the Hubble solar exclusion zone in early November.

You can find most of this information and more on the HST Homepage by entering "12725" in the Prop. ID box.


Proposal ID = 12189
Principle Investigator = Walter Jaffe
Title = "Do stars ionize the filaments in NGC 1275?"
Time = Sep 25, 2011
Target = NGC 1275
Instrument = COS

Background:

The center of a rich cluster of galaxies is a special position and the galaxies that reside there are like no others in the universe. These are the most massive galaxies, the result of a process called galactic cannibalism. NGC 1275 (also know as the radio galaxy Perseus A) is the brightest cluster galaxy in the Perseus cluster of galaxies and is famous as one of the most peculiar galaxies due to the wide variety of phenomena that are occurring. It is a powerful radio and x-ray source; is at the center of a "cooling flow"; has an active galactic nucleus (AGN) which requires the existence of a supermassive black hole; has both inner low-velocity filaments (possibly associated with the AGN) but also has outer high-velocity filaments (~ 3000 km/s - probably related to a merging event); and has a rich population of young super star clusters. This program is designed to determine what ionizes the filaments in this system; star formation or the central nucleus.

A nice graphic (which can be toggled to show the HST, VLA, and Chandra images of this galaxy) is available at:

http://apod.nasa.gov/apod/ap080822.html

Paraphrasing from the abstract:

Brightest Cluster Galaxies (BCGs) in cool core clusters show filaments of line emitting gas whose ionization physics has been much studied but little understood. Some filaments show blue knots suggesting young star clusters; others do not. We request deep COS G140L FUV spectra of five regions in the filaments surrounding the BCG NGC 1275 in the nearby Perseus cluster. Analysis of the spectra, and particularly the [CIV] feature will clarify whether the filaments are ionized by normal stars, ultra-hot stars, or a non-thermal source weak in FUV photons. The possible role of the active nucleus will be investigated by selecting regions located at various distances from the nucleus. Understanding the ionization and heating of these filaments, and why some filaments form stars, whilst others are prevented from collapsing, is important not only to the understanding of cool core clusters, but also to the wider issue of galaxy formation.

You can find most of this information and more on the HST Homepage by entering "12189" in the Prop. ID box.


Proposal ID = 12166
Principle Investigator = Harald Ebeling, University of Hawaii
Title = "A Snapshot Survey of The Most Massive Clusters of Galaxies"
Time Observed =  Sep 18, 2011 05:45:18 - 06:27:41
Target = MACSJ1328.2+5244 
Instrument = ACS/WFC

Background:

Galaxies are rarely found alone; they tend to form in groups and clusters. The most massive clusters have several thousand galaxies in them. Understanding the process of "hierarchical" clustering and merging (i.e., small galaxies form first and merge to form larger galaxies) is a central theme in the study of how galaxies evolve. It is difficult to identify distant clusters of galaxies where only a few of the most luminous galaxies can be detected. Fortunately, the hot gas within massive clusters of galaxies also emit Xrays, and this can be used as a signpost for finding these clusters. This proposal aims to find large numbers of very distant clusters by using Hubble, in snapshot mode, to examine candidates from the ROSAT (Rontgensatellit = a German X-Ray satellite telescope) Bright Source Catalogue. Followup observations are then made using a wide range of telescopes, both ground- and space-based (i.e., University of Hawaii, Keck, Subaru, CFHT, Chanda X-Ray Observatory and Hubble). This demonstrates the synergy necessary to understand the evolution of the universe in detail by using a wide variety of telescopes and wavelength regimes.

Paraphrasing from the abstract:

We propose the continuation of our highly successful HST/ACS SNAPshot survey of a sample of 123 very X-ray luminous clusters in the redshift range 0.3-0.7, detected and compiled by the MACS (Massive Cluster Survey). These systems frequently exhibit strong gravitational lensing as well as spectacular examples of violent galaxy evolution. The proposed observations will provide important constraints on the cluster mass distributions, on the physical nature of galaxy-galaxy and galaxy-gas interactions in cluster cores, and will yield a set of optically bright, lensed galaxies for further 8-10m spectroscopy. For those of our targets with existing ACS SNAPshot images, we propose SNAPshots in the WFC3 F110W and F140W passbands to obtain colour information that will greatly improve the secure identification of multiple-image systems and may lead to the lensing-enabled discovery of very distant galaxies at z>5. Colour information will also help identify star-forming regions and thus shed light on the nature of the physical processes driving galaxy evolution in cluster cores.

You can find most of this information and more on the HST Homepage by entering "12166" in the Prop. ID box.


Proposal ID = 11670
Principle Investigator = Peter Garnavich, University of Notre Dame
Title = "The Host Environments of Type Ia Supernovae in the SDSS Survey"
Time Observed = Sep 4, 2011 22:57::17 - 23:38:32
Target = SN 1308
Instrument = ACS/WFC

Background:

The discovery of dark energy is one of the most important results in astronomy, and physics, today. One of the primary tools for studying dark energy is to determine the size of the universe as a function of time using a "standard candle" (i.e., an object of know brightness). Observations of type 1a supernovae are the tool of choice for this critical observation. A better understanding of the physics behind these standard candles may lead to more precise measurements, and hence a better understanding of dark energy. This proposal aims to determine the star formation rate in the vicinity of a large sample of supernovae 1a's, in order to differentiate between two current models for the formation of these objects. This is an example of a snapshot proposal, which provides a long list of potential targets requiring an orbit or less to observe. A subset of these are then used to "fill in the cracks", hence providing a more efficient Hubble observing schedule.

Paraphrasing from the abstract:

The Sloan Digital Sky Survey Supernova Survey has discovered nearly 500 type Ia supernovae and created a large, unique, and uniform sample of these cosmological tools. As part of a comprehensive study of the supernova hosts, we propose to obtain Hubble ACS images of a large fraction of these galaxies. Integrated colors and spectra will be measured from the ground, but we require high resolution HST imaging to provide accurate morphologies and color information at the site of the explosion. This information is essential in determining the systematic effects of population age on type Ia supernova luminosities and improving their reliability in measuring dark energy. Recent studies suggest two populations of type Ia supernovae: a class that explodes promptly after star-formation and one that is delayed by billions of years. Measuring the star-formation rate at the site of the supernova from colors in the HST images may be the best way to differentiate between these classes.

You can find most of this information and more on the HST Homepage by entering "11670" in the Prop. ID box.


Proposal ID = 12206
Principle Investigator = Mark Westmoquette, European Southern
    Observatory, Germany
Title = "Starburst-driven shocks and feedback in the near-IR at high
    resolution"
Time Observed = Sep 3, 2011, 13:44:35 - 17:26:13
Target = NGC 253
Instrument = WFC3/IR

Background:

Astronomers have a relatively well developed theoretical understanding of the structure of stars. This allows them to explain a wide range of stellar observations ranging from their colors and masses to how they evolve with time. No comparably detailed understanding of the process of star formation itself exists, however, due to the greater complexity of the physical processes involved. An important component of such a model will be the understanding of feedback, the process by which young massive stars and supernova either hinders (e.g, by blowing a wind which removes the reservoir of gas), or enhances (e.g., by forming shocks) the formation of stars in the vicinity. This proposal uses the narrow-band infrared filters on WFC3 to study the formation of shocks in starburst galaxies, and attempts to relate these shocks to the properties of the galaxy as a whole.

Paraphrasing from the abstract:

Starburst-driven feedback is one of the primary engines of galaxy evolution throughout the Universe. Yet, the theoretical foundation of mechanical feedback is, to date, unconstrained by observations. We propose to investigate this fundamental aspect of star formation directly through near-infrared narrow-band imaging of Pa-beta emission and the shock-excited [FeII] line in a small but representative sample of nearby (2.5-20 Mpc) starbursts with known H-alpha outflows. These data will allow us to: [1] provide a complete census of the shocks inside and around the starburst regions; [2] measure the supernova (SN) rate and relate this to the level of mechanical energy deposited by these SNe into the ISM; [3] investigate the relation between the shocked regions and the galaxy morphology in order to study the conditions under which feedback transitions from a localized process to a galactic-scale phenomenon; [4] study the spatial evolution and history of star formation in these galaxies.

You can find most of this information and more on the HST Homepage by entering "12206" in the Prop. ID box.


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