Calendar

Oct
8
Mon
Planetary Group meeting
Oct 8 @ 2:00 pm – 3:00 pm
Oct
12
Fri
Colloquium: Michelle Creech-Eakman (Host: Moire Prescott)
Oct 12 @ 3:15 pm – 4:15 pm
Colloquium: Michelle Creech-Eakman (Host: Moire Prescott) @ BX102

The Magdalena Ridge Observatory Interferometer: Design Details and Progress towards First Light with UT#1

Michelle Creech-Eakman, New Mexico Tech

The Magdalena Ridge Observatory Interferometer (MROI), a 10-telescope optical/near-IR interferometer in central NM, has been conceived to be the most ambitious optical interferometric array under construction to date. With baselines ranging from 7.8 to 347 meters, and limiting magnitudes of 14 at H band, it will be able to assess many thousands of astronomical targets on spatial scales of 10’s to 0.1’s of milliarcseconds. This is achieved through several careful design choices and trade-offs which should allow the MROI to reach 4-5 magnitudes deeper than similar facilities can achieve today. After over a decade of funding from NRL and the major partner institutions (NM Tech and Cambridge University), new funding was obtained in late 2015 via a Cooperative Agreement between NM Tech and the Air Force Research Lab (AFRL) to bring the facility to a three-interferometer system capable of observing geosynchronous satellites. However, we still maintain an exciting and compelling astronomical portfolio which will produce statistical samples of: YSOs and their surrounding disks, systems dominated by mass-loss and mass-transfer, pulsating stars and binary star systems, and images of the environs of AGN in nearby galaxies. An overview of the major design components of this ambitious imaging machine, recent progress, and plans for MROI for the next 3 years under the AFRL Cooperative Agreement will be presented.

Oct
19
Fri
Colloquium: Sanchayeeta Borthakur (Host: Kristian Finlator)
Oct 19 @ 3:15 pm – 4:15 pm
Colloquium:  Sanchayeeta Borthakur (Host: Kristian Finlator) @ BX102

Understanding How Galaxies Reionized the Universe

 Sanchayeeta Borthakur, Arizona State University

Identifying the population of galaxies that was responsible for the reionization of the universe is a long-standing quest in astronomy. While young stars can produce large amounts of ionizing photons, the mechanism behind the escape of Lyman continuum photons (wavelength < 912 A) from star-forming regions has eluded us. To identify such galaxies and to understand the process of the escape of Lyman continuum, we present an indirect technique known as the residual flux technique. Using this technique, we identified (and later confirmed) the first low-redshift galaxy that has an escape fraction of ionizing flux of 21%. This leaky galaxy provides us with valuable insights into the physics of starburst-driven feedback. In addition, since direct detection of ionizing flux is impossible at the epoch of reionization, the residual flux technique presents a highly valuable tool for future studies to be conducted with the upcoming large telescopes such as the JWST.

Oct
29
Mon
Planetary Group meeting
Oct 29 @ 2:00 pm – 3:00 pm
Nov
2
Fri
Colloquium: Kate Follette (Host: Moire Prescott)
Nov 2 @ 3:15 pm – 4:15 pm
Colloquium: Kate Follette (Host: Moire Prescott) @ BX102

How to Take Pictures of Baby Planets

Kate Follette, Amherst College

Of the thousands of known extrasolar planets, why are the dozen or so directly imaged exoplanets among the most important despite their apparently anomalous properties within the general exoplanet population (>10 astronomical units, >2x the mass of Jupiter)? What are the prospects for (and recent successes in) detecting younger, lower-mass and/or closer-in planets via direct imaging? I will discuss the current state of the art in the field of high-contrast imaging of extrasolar planets and the disks of gas and dust from which planets form (“circumstellar disks”). I will place particular emphasis on a subset of objects that host both disks and (likely) planets – the so-called “transitional disks”. These young circumstellar disks are almost certainly actively undergoing planet formation, and yet the presence of disk material complicates our ability to isolate light from planets and/or protoplanets embedded within them. I will end by discussing recent results from the Giant Accreting Protoplanet Survey (GAPplanetS) of 15 southern-hemisphere transition disks. The GAPlanetS survey aims to find protoplanets embedded in transitional disks through a distinctive signature at hydrogen wavelengths, and has so far discovered: 2-3 planets, 1 accreting M-dwarf stellar companion, and 1 disk feature masquerading as a planet.

Nov
9
Fri
Colloquium: Laura Chomiuk (Host: Moire Prescott)
Nov 9 @ 3:15 pm – 4:15 pm
Colloquium: Laura Chomiuk (Host: Moire Prescott) @ BX102

Rethinking the Fundamentals of Classical Nova Explosions

Laura Chomiuk, MSU

Over the past few years, a revolution has been taking place in our understanding of classical novae, largely driven by the discovery of GeV gamma-rays emanating from these garden-variety explosions. These gamma-rays hint that shocks are energetically important—perhaps even dominant—in novae. I will present our burgeoning understanding of shocks in novae, from both multi-wavelength observational and theoretical perspectives, and illustrate how novae can be used as testbeds to understand other shock-powered explosions.

Nov
12
Mon
Planetary Group meeting
Nov 12 @ 2:00 pm – 3:00 pm
Nov
26
Mon
Planetary Group meeting
Nov 26 @ 2:00 pm – 3:00 pm
Nov
30
Fri
Colloquium: John Stocke (Host: Rene Walterbos)
Nov 30 @ 3:15 pm – 4:15 pm
Colloquium: John Stocke (Host: Rene Walterbos) @ BX102

Colloquium Title

Colloquium Speaker Name, Affiliation

Abstract text

Dec
6
Fri
Colloquium: Elise Boera (Host: Kristian Finlator)
Dec 6 @ 3:15 pm – 4:15 pm
Colloquium: Elise Boera (Host: Kristian Finlator) @ BX102

Revealing reionization with the thermal history of the intergalactic medium

Elisa Boera, SISSA Trieste

During hydrogen reionization the UV radiation from the first luminous sources injected vast amount of energy into the intergalactic medium, photo-heating the gas to tens of thousands of degree Kelvin. This increase in temperature has left measurable `imprints’ in the thermal history of the cosmic gas: a peak in the temperature evolution at the mean density and a smoothing out of the gas in the physical space by the increased gas pressure following reionization (i.e. Jeans smoothing effect). The structures of the HI Lyman-alpha forest at high redshift are sensitive to both these effects and therefore represent a powerful tool to understand when and how reionization happened. I will present the most recent constraints on the thermal history of the intergalactic medium obtained using the Lyman-alpha forest flux power spectrum at z>5. I will show how these results can be used to obtain information on the timing and the sources of the reionization process and I will discuss their consistency with different possible reionization scenarios.