Radiative Transfer Models of the Galactic Center

This thesis discusses research being done to understand the inner parts of the Milky Way Galaxy. We already know that there are dense star clouds, a supermassive black hole, and a large bar structure, but much of the inner galaxy is shrouded in mystery. Dust absorption, for one thing, prevents us from seeing the galactic center directly with our eyes. To help understand the elusive inner Milky Way, we examine radio telescope data taken in Antarctica by Oberlin College Professor Chris Martin. His gigahertz radio observations were already analyzed to help understand how gas funnels into the Milky Way\u27s supermassive black hole. We study this data further to characterize turbulence and predict how hot or cold the gas is. The analysis of this data will also help prepare for the next thing: Herschel Space Observatory. This European telescope is scheduled to be launched in late April and will begin taking data in the fall of 2009. Chris Martin was granted 125 hours of observation time on the telescope to study the Inner Milky Way

Radiative Transfer Models of the Galactic Center

This thesis discusses research being done to understand the inner parts of the Milky Way Galaxy. We already know that there are dense star clouds, a supermassive black hole, and a large bar structure, but much of the inner galaxy is shrouded in mystery. Dust absorption, for one thing, prevents us from seeing the galactic center directly with our eyes. To help understand the elusive inner Milky Way, we examine radio telescope data taken in Antarctica by Oberlin College Professor Chris Martin. His gigahertz radio observations were already analyzed to help understand how gas funnels into the Milky Way\u27s supermassive black hole. We study this data further to characterize turbulence and predict how hot or cold the gas is. The analysis of this data will also help prepare for the next thing: Herschel Space Observatory. This European telescope is scheduled to be launched in late April and will begin taking data in the fall of 2009. Chris Martin was granted 125 hours of observation time on the telescope to study the Inner Milky Way

Disintegrating Exoplanets: Creating Size Constraints by Statistically Peering Through the Debris

We study two intriguing disintegrating exoplanets, Kepler-1520b and K2-22b, and attempt to constrain the size of the underlying objects. These two planets are being disintegrated by their host stars, spewing dust and debris pulled from their surface into tails that trail and precede the exoplanet in its orbit, making it difficult to discern the true nature of the object. We attempted to peer through the dust cloud to put a constraint on the maximum radii of these exoplanets. While previous studies have done this in the past by selecting shallow transit events, we attempt a new statistical approach to model the intrinsic astrophysical and photon noise distributions simultaneously. We assume that the lightcurve flux distribution is distributed as a convolution of a Gaussian photon noise component and a Raleigh astrophysical component. The Raleigh curve has a finite flux maximum, which we fit with a Hamiltonian Markov Chain. With these methods, a more accurate flux maximum may be estimated, producing a more accurate and better final value for the size of these exoplanets. To determine statistical significance, we used the python package PyMC3 to find the posterior distribution for our data with Gaussian, Rayleigh, and joint function curves and plotting it against our collected flux. After completing this analysis, we were unable to constrain the radii of the exoplanets, as the forward scattering by dust dominates over dust extinction. However, this does mean that we were able better able to constrain the astrophysical variability and its maximum with our analysis.Comment: 10 Pages, 13 Figures, In preparation for journal submissio

Observations Of Disintegrating, Evaporating And Hot Planet Atmospheres With Transmission Spectra

Hot exoplanets with semi-major axes smaller than 0.05 AU can go considerable alteration from the high energy radiation of their host stars radiation from driving winds to altering the thermal profiles to disintegrating nearby planets. A variety of exoplanets are studied in this high irradiation environment with different consequences on their atmospheres. The escaping winds from the transiting hot Jupiter HD 209458b are measured with a novel limb brightened transit model for ultraviolet wavelengths. The hot exoplanet CoRoT-1b is used as a test case for the hypothesis that TiO and VO molecules (which can exist in equilibrium at high temperatures) can create a temperature inversion in the planet by absorbing stellar ultraviolet radiation. Finally, the escaping debris from the disintegrating planet candidate KIC 12557548b are characterized with spectroscopy to constrain the size of dust particless in its escaping winds

Identification of WISE J000100.45+065259.6 as an M8.5+T5 Spectral Binary Candidate

[not part of RNAAS note] We report the discovery of WISE J000100.45+065259.6 as a very low mass star/brown dwarf spectral binary candidate, on the basis of low resolution near-infrared spectroscopy obtained with IRTF/SpeX. Decomposition of the spectrum indicates component types of M8.5+T5 with a predicted $\Delta{J}$ = 3.5. As the majority of confirmed spectral binary candidates to date are very closely-separated systems ($\rho$ $\lesssim$ 3 AU; $P$ $\lesssim$ 15~yr), this source may provide mass measurements across the hydrogen burning limit within the decade.Comment: 3 pages, 1 figure, accepted to Research Notes of the AA

Single Object & Time Series Spectroscopy with JWST NIRCam

JWST will enable high signal-to-noise spectroscopic observations of the atmospheres of transiting planets with high sensitivity at wavelengths that are inaccessible with HST or other existing facilities. We plan to exploit this by measuring abundances, chemical compositions, cloud properties, and temperature-pressure parameters of a set of mostly warm (T 600 - 1200 K) and low mass (14 -200 Earth mass) planets in our guaranteed time program. These planets are expected to have significant molecular absorptions of H2O, CH4, CO2, CO, and other molecules that are key for determining these parameters and illuminating how and where the planets formed. We describe how we will use the NIRCam grisms to observe slitless transmission and emission spectra of these planets over 2.4 - 5.0 microns wavelength and how well these observations can measure our desired parameters. This will include how we set integration times, exposure parameters, and obtain simultaneous shorter wavelength images to track telescope pointing and stellar variability. We will illustrate this with specific examples showing model spectra, simulated observations, expected information retrieval results, completed Astronomer's Proposal Tools observing templates, target visibility, and other considerations