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What SOFIA Observations Tell Us About Planetary Debris Disks

Steward Scientist Kate Su will be holding a press conference at the AAS meeting Jan 7. The title is "What SOFIA Observations Tell Us About Planetary Debris Disks." Here is the meeting abstract for her Friday AAS talk. We will have the press release when it's available.

Oral Talk: Nature of the Warm Excess in eps Eri: Asteroid belt or Dragged-in Grains
Kate Y. Su, George Rieke, Massimo Marengo, & Karl R. Stapelfeldt

Epsilon Eri and its debris disk provide a unique opportunity to probe the outer zones of a planetary system due to its young age (roughly 1 Gyr) and proximity (3.22 pc, the closest prominent debris disk by more than a factor of two). It is the Rosetta Stone for more distant exoplanetary debris systems and thus critical to understanding the mid-term evolution of our Solar System. From resolved images in the far-infrared and submillimeter along with spectra from 10-35 and 55-95 microns, the eps Eri disk was suggested to have a complex structure, with multiple zones in both warm (asteroid-like) and cold (KBO-like) components. Alternatively, the warm excess can also originate from small grains in the cold disk, which are transported inward by the combination of Poynting-Robertson and stellar wind drags. Here we present a SOFIA/FORCAST 35 micron image of the system, and provide additional constraints on the nature of the warm excess inferred from previous Spitzer and Herschel observations.

/what-sofia-observations-tell-us-about-planetary-debris-disks

2/25/16 SO/NOAO Joint Colloquium Series: Marcia Rieke, Steward

Date: 
Thursday, February 25, 2016 - 4:00pm to 5:00pm
Room: 
SO N210

Title: NIRCam: Your Next Near-Infrared Camera in Space

Abstract:
NIRCam is a very flexible imager that includes features that will enable transit spectroscopy as well as converting NIRCam into the facility wavefront sensor. The capabilities of NIRCam will be presented in the context of examples drawn from the NIRCam team's guaranteed time observing program. This program ranges from deep surveys searching for the first galaxies to studies of KBOs in the outer solar system, and uses essentially all of the NIRCam observing modes.

3/3/16: SO/NOAO Joint Colloquium Series: Mary Putman, Columbia University

Date: 
Thursday, March 3, 2016 - 4:00pm to 5:00pm
Room: 
SO N210

Title: Gas Flows at Various Astronomical Scales

Abstract:
I will discuss gas flows onto dark matter halos of various sizes and include results from observations and simulations. These include gas flows for local galaxy clusters, the dwarf spiral galaxy M33, and our Milky Way. The gas transitions during the flows and is key to understanding ongoing star formation.

Neither Rain Nor Sleet Nor Dark Of Night...

While making tests of the JWST telescope instrument suite, the teams, including a contingent from UA (Stacey Alberts, Karl Misselt, and Lisa May Walker, among others over an extended period) were stranded at Goddard in a blizzard. HERE is an article from Atlantic. A NASA press release about the primary mirror completion is found HERE.

 

/neither-rain-nor-sleet-nor-dark-night
Buddy Martin and Dae Wook Kim Speak About Building Mirrors
Mirror polishing. Image credit: Richard F. Caris Mirror Lab

Buddy Martin and Dae Wook Kim Speak About Building Mirrors

Buddy Martin and Dae Wook Kim have written an article for "The Conversation." In it they talk about the state of the art in mirror making, using the decisions made by Roger Angel and his group since the early 1980s, and now by the GMT project and the Richard F. Caris Mirror Lab, as examples. The Caris Mirror Lab has made a remarkable number of large mirrors in use in telescopes around the world and is hard at work on the segments of the GMT. These segments are among the most aspheric ever polished, a testament to the inventions at the Caris Lab, and a testament to its great crew, some of whom have worked on mirrors here at Steward for 20-30 years or longer.

1/21/16: SO/NOAO Joint Colloquium Series: Ian McGreer, Steward

Date: 
Thursday, January 21, 2016 - 4:00pm to 5:00pm
Room: 
SO N210

Title: Growing Supermassive Black Holes at High Redshift

Invited AAS Talk on Event Horizon Telescope

Professor Feryal Ozel gave a plenary talk at the American Astronomical Society Meeting on Jan 6, entitled "Black Hole Physics with the Event Horizon Telescope." The abstract of her talk follows:

The Event Horizon Telescope is an experiment that is being performed on a large and ever-increasing array of radio telescopes that span the Earth from Hawaii to Chile and from the South Pole to Arizona. When data will be taken with the full array, it will image the event horizons of the supermassive black hole at the center of our Galaxy, Sagittarius A*, and the black hole at the center of M87, with an unprecedented 10 microarcssecond resolution. This will allow us to take the first ever pictures of black holes at 1.3 and 0.85 mm wavelengths and look for the shadow that is a direct evidence for a black hole predicted by the theory of General Relativity. In addition, the Event Horizon Telescope will also enable us to study the process by which black holes accrete matter and grow in mass. I will discuss the theoretical developments in simulating the properties of the black hole accretion flows and their expected images using state-of-the-art algorithms and high performance computing. Interpreting the upcoming observations within this theoretical framework will open new horizons in black hole astrophysics.

You can read two accounts of her talk HERE and HERE.

/invited-aas-talk-event-horizon-telescope
The First Images of Planets in the Process of Formation

Steward astronomers have imaged forming planets for the first time. Steph Sallum and Kate Follette, working with Josh Eisner and Laird Close, observed the young star LkCa 15 using the Large Binocular Telescope and the Magellan Adaptive Optics system. LkCa 15 hosts a transition disk - a protoplanetary disk with an inner, solar-system-sized clearing. In the clearing they detect three points of light in the infrared, one of which is also seen in the visible, Hydrogen-alpha (H-alpha) emission line. The companions' infrared brightnesses agree with those expected for forming planets, and the H-alpha detection directly traces shocked hydrogen gas falling onto one of the protoplanets. The source positions, compared to previous observations taken at Keck, are consistent with circular orbits aligned with the outer disk. LkCa 15 is the first system in which astronomers can observe planet formation processes directly. You can see the UA press release HERE. The accepted journal article is at "Nature, vol 527, 342-344 (Nov 2015)." The Arizona Daily Star article can be foundHERE.

/first-images-planets-process-formation

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