Testing a novel method to map the 3D distribution of gas clouds in intergalactic space

Thesis (S.B.)--Massachusetts Institute of Technology, Dept. of Physics, June 2011."June 2010." Cataloged from PDF version of thesis.Includes bibliographical references (p. 45-46).We propose a new method to detect intergalactic Lyman a emitter and absorber systems by comparing broadband and narrowband images. The narrowband observations were carried out with the Maryland-Magellan Tunable Filter (MMTF) at central wavelengths of 5120A and 5140A and pointing to the Chandra Deep field South. The broadband images were obtained through the European Southern Observatory public database. Catalogues of galaxies were constructed from all images, taking the R broadband as a reference for locating objects. Via color-color and color-magniude diagrams, and taking the Steidel et al. color selection criteria as a reference, we were able to identify numerous Ly a emission and absorption candidates. This serves as a proof of concept that narrowband absorption could be used to mao the distribution of Lyman limit systems in 3D.by Daniella C. Bardalez Gagliuffi.S.B

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

High Resolution Imaging of Very Low Mass Spectral Binaries: Three Resolved Systems and Detection of Orbital Motion in an L/T Transition Binary

We present high resolution Laser Guide Star Adaptive Optics imaging of 43 late-M, L and T dwarf systems with Keck/NIRC2. These include 17 spectral binary candidates, systems whose spectra suggest the presence of a T dwarf secondary. We resolve three systems: 2MASS J1341–3052, SDSS J1511+0607 and SDSS J2052–1609; the first two are resolved for the first time. All three have projected separations <8 AU and estimated periods of 14–80 years. We also report a preliminary orbit determination for SDSS J2052–1609 based on six epochs of resolved astrometry between 2005 and 2010. Among the 14 unresolved spectral binaries, 5 systems were confirmed binaries but remained unresolved, implying a minimum binary fraction of 47_(-11)^(+12) for this sample. Our inability to resolve most of the spectral binaries, including the confirmed binaries, supports the hypothesis that a large fraction of very low mass systems have relatively small separations and are missed with direct imaging