Abstracts

Optical Astronomy: A New Object Detection Algorithm
David Chavera, University of Rochester

The Transient Optical Robotic Observatory of the South (TOROS) is an up-and-coming observatory located at latitude 24.61 South and longitude 67.32 West, and at an altitude of 4650 meters in the province of Salta, Argentina. It was constructed through a partnership with The University of Texas at Brownsville, The Universidad Nacional de Cordoba, Texas A&M University, aLIGO, and Caltech University . TOROS is currently being used to try and detect remnants of early supernovae, as well as transients. Eventually, it will be used to observe sources of gravitational waves that aLIGO detects. For my project, I tested the efficiency of different object detection algorithms to see if they could be used by TOROS. The software I tested is known as OpenCV (Open Source Computer Vision Library). To test its efficiency, I first created an animated video of image data acquied by the CSTAR (Chinese Small Telescope ArRay Telescope ) which collects data using similar methods. After its creation, we found that the video was too complex. To solve this I created a simple video using the programming language known as Python. Once created, I tested two algorithms on the video- Optical Flow, and Background Subtraction. Background Subtraction worked as expected. Optical Flow, however, produced two slightly different algorithms that could be useful in different ways. Though it's clear, through our work, that OpenCV has great potential for being used in optical astronomy, we hope to first test it on more complicated videosvideos like the one acquired by the CSTAR telescope.

Searching for High Redshift Galaxies using the Brightest of Reionizing Galaxies Survey
James Diekmann, University of Texas at Austin

We examine 100 fields from the HST Brightest of Reionizing Galaxies (BoRG) Survey to detect high redshifts galaxies at z=8 and possibly z=9. By extracting photometric redshifts for each candidate galaxy, a probability relating the likelihood of a galaxy at a particular redshift can be determined. From previous studies in the BoRG 58 field, a handful of candidate z=8 galaxies have been found through color-color relations (et al. Trenti). We expect to find similar results with photometric redshifts and expect to find more candidate redshift galaxies within the remaining BoRG fields.

The Life Cycle of a VIRUS: a Production in Three Parts
Eric Dreasher, University of Texas at Austin
Ingrid Johnson, University of Texas at Austin
Andrew Peterson, University of Texas at Austin

This engaging three part series focuses on the exciting life of scientific instrumentation. Join us as we take you on a journey through the history of the VIRUS project, into its development and production, and around the snags and solutions of creating something that’s never been done before. By the way, we’re bringing props. And they’re awesome.

Investigating Emission Line Profiles of Accreting T Tauri Stars
Joshua Jones, Rice University

Numerous discoveries of extra solar planets over the last two decades have raised many questions regarding the mechanisms behind the process of planetary formation. Of key interest is establishing an accurate timescale for the process. To this end, it is necessary to study young systems with newly formed or still forming planets. Such systems can be found around T Tauri stars, which are young protostars that have only just emerged from the molecular clouds were they formed. Of particular interest are the classical T Tauri stars (CTTSs) which are still surrounded by the circumstellar accretion disks that are believed to be the sites of planet formation. We use high resolution optical spectroscopy to examine emission line variations from CTTSs in the Taurus-Aurigae star forming region that show some evidence for having very low mass, possibly planetary, companions in short period orbits. In particular, we focus on the H-alpha line in which we are looking for evidence of emission from low mass companions, and the Na D lines, where we look for evidence of possible cometary infall. We report preliminary evidence of periodic variations in the H-alpha emission of CI Tau, with a period similar to that of its suspected companion.

The Strange Case of GSC 05206: 01013
Mahfuz Krueng, Texas Tech University

The purpose of the research is to model the newly discovered variable star GSC05206: 01013. This variable star is an eclipsing binary and we aimed to characterize various properties of the star involved. The research is based on observations done in 2013 and 2014 at the Texas Tech University’s Preston Gott Observatory. Subsequent data analysis was conducted primarily using Canopus photometry software. The system is far more complex than was expected and clearly is not a simple eclipsing binary. Most recent observations indicate this binary system to be two eclipsing binaries.

Evidence of Decay of Turbulent Shocks in the ISM
Rebecca Larson, University of Texas at Austin

We utilize observations of submillimeter rotational transitions of CO to identify previously predicted turbulent dissipation of shocks in molecular clouds. During the earliest stages of star formation, when the protostar is still enveloped by an interstellar cloud of gas and dust, CO observed toward positions close to active sites of star formation, but not within outflows, can trace turbulent dissipation of shocks stirred by formation processes. Although the transitions are difficult to detect at individual positions, our Herchel- SPIRE survey of prototars provides a grid of spectra at numerous spatial positions. We analyzed a grand average of positions, not within outflows, near six protostars from the COPS (PI: J. Green) open time program, finding good agreement with predictions of models of turbulent dissipation in high velocity (few km/s), high density (10$^{3.5}$ cm$^{-3}$) material. We find evidence that shock dissipation may even be occurring in material unassociated with any protostar, at slightly lower (10$^{3}$ cm$^{-3}$) densities.

Core and Competitive Accretion in Recent Numerical Simulations of Star Formation in the First Galaxies
Ross Meyer, University of Texas at Austin

The relative importance of the Core Accretion and Competitive Accretion models of star formation has remained an open problem in the theory of star formation, and has, thus far, only been thoroughly investigated within the context of the Milky Way. The basic premise of the core accretion model is that stars form via the collapse of centrally concentrated, gravitationally bound "core" regions. These regions define the scale at which the gas in a fragmenting protocluster environment becomes unstable to global gravitational collapse. Thus, stars gather their mass in a pre-stellar stage, rather than during the stellar formation process itself. In the competitive accretion model, fragmentation into pre-stellar cores forms low mass stars, but is inefficient enough to leave large, unbound reservoirs of gas from which these stars can later accrete. This gas is eventually pulled into stellar clusters, whose large-scale gravitational potential drives massive star formation by effectively funneling gas toward stars near the center of the cluster. These models make testable predictions: the core accretion model implies that pre-stellar core mass should determine final stellar mass, with the core mass function setting the stellar initial mass function, and that the fraction of mass converted to stars per dynamical time should be small in gas clouds much larger than an individual core; competitive accretion predicts that an individual star's accretion rate (and thus final mass) should be determined by its tidal radius relative to the cluster potential, rather than the amount of gas bound to it at formation time. Recent numerical simulations of structure formation in the first galaxies by Safranek-Shrader et al. (2012, 2014a, 2014b) provide a novel opportunity to test these predictions and characterize the explanatory power of each model. These hydrodynamic simulations model the formation of the first low-mass stars, occurring after Population III stars have enriched their host cosmic halos with metal. We will discuss salient aspects of the simulations, as well as data analysis techniques used to test the aforementioned predictions.

A Multi-band Extension of the Analysis of Variance Period Finding Algorithm
Nicholas Mondrik, Texas A&M University

One of the largest challenges facing modern astronomical surveys is the automated classification of sources. In the case of variable stars, periods are among the most useful features for classification algorithms. In surveys such as the Dark Energy Survey, which cover a large area of the sky with relatively few visits, single band period finding algorithms can struggle due to poor phase coverage in any one band. However, these single band algorithms throw away data in the form of other bands that can potentially hold more information about the period of the variable source. We present here an extension ofa single band period finding algorithm to include information about the period contained in other bands. We generate light curves of RR Lyrae stars in 5 bands and compare the performance of the multi-band algorithm to its single band implementation. By including these extra bands we show improved performance for poorly sampled light curves over long baselines in simulated data.

Hubble Space Telescope Imaging of Galaxies in a Super-Group at z~0.37
Jonathan Monroe, Texas A&M University

We study a super-group of galaxies at z~0.37 (SG1120) using high resolution imaging taken with the Hubble Space Telescope. SG1120 provides a unique probe of how the group environment affects galaxy evolution because SG1120 is composed of four galaxy groups that will merge to form a massive galaxy cluster. With the multi-filter imaging, we generate large image mosaics and color images to: 1) measure galaxy fluxes and colors and 2) identify morphological signs of ram pressure stripping and compact star forming regions.

Diffuse X-ray Emission in Nearby Face-on Spiral Galaxies
Marilyn Moore, University of Texas San Antonio

X-ray observations of face-on spiral galaxies reveal detectable, diffuse emission present across the face of nearby galaxies. Whether that emission represents hot gas or the emission from unresolved point sources remains to be determined. We present early results for spectral fits to two arms in M51 which reveal differences in the total flux and line emission present. We also present early results from comparisons between wavebands for M51 and M83.

The Betelgeuse Project
Sarafina Nance, University of Texas at Austin

We seek to constrain the mass and evolutionary state of Betelgeuse, a supergiant in the constellation Orion, to determine when it will explode as a supernova. We compile a suite of stellar evolution models (both rotating and non-rotating) of masses ranging from 15M to 25M to extract characteristic frequencies associated with convective regions. Detection of these frequencies could allow us to peer into the star. We also constrain models with observed values of temperature, radius, luminosity, and rotational velocity. We find it is difficult to match all of the constraints with theoretical models. In particular, matching the observed rotational velocity of 5 km/sec seems to require that Betelgeuse is at the base, rather than the tip, of the red giant branch. This would imply that Betelgeuse is far from explosion, perhaps 100,000 years, but in a very special, brief phase of its evolution. Detection of predicted convective frequencies would help to confirm the evolutionary state.

Exoplanet Transit of HAT-P-20 Abstract
Anthony Rifaat, Baylor University

An exoplanet is a planet that orbits another star outside our solar system. Exoplanet detection, which started in the late 1980s with the discovery of a brown dwarf orbiting the star Gamma Cephei, has become one of the most exciting new fields of observational astronomy with hundreds of new exoplanets being discovered since then. There are several methods of detecting exoplanets, the most common ways being the use of transit photometry and radial velocity (the method used for the first detection in1988). Using the method of transit photometry, I created and analyzed the light curve of HAT- P -20 in order to detect and examine one of its planets, HAT-P-20b, moving across our plane of view of the star. To collect the data, I used the 24’’ telescope at the Paul and Jane Meyer Observatory in Clifton, TX as well as AstroImageJ 2.1 software to analyze the gathered material. By examining the light curve, several interesting facts about the exoplanet itself can be determined, such as mass, size, etc.

Luminosity-density Fluctuations of the Cosmic Near-Infrared Background
Sae Saito, University of Texas at Austin

The first generation stars are thought to be responsible for reionizing the universe. The ionizing photons emitted by early stars at high redshifts would be redshifted into near-infrared. Thus it is important to search for this near-infrared light to learn about early star formation and reionization. The cosmic Near- Infrared Background (NIRB) is one of the methods we can use to observe this redshifted light. Observing angular fluctuations of the NIRB on the sky can provide information about the early stars, halos, and surrounding ionized regions in the intergalactic medium (IGM). These angular fluctuations reflect evolution and spatial clustering of the early galaxies responsible for reionization, since they causefluctuations in time and space in the luminosity-density of radiation seen today redshifted into the nearinfrared. Our study focuses on wavelength band 1-2μm, as it appears to be where a peak of spectrum is. We used C2-Ray radiative transfer simulation data and calculated the luminosity of different contributions to predict power spectrum of fluctuations. In the future work, we will focus on predicting the angular power spectrum of fluctuations. Moreover, we will extend our research to the analysis of simulations that include mini halos.

Investigation of the Photophoretic Force
Jeremy Smallwood, Baylor University

The details of planet formation are still largely unknown. A number of forces play a role in the coagulation process, where solid material in a protoplanetary disk grows from micrometer sized dust grains to kilometer sized objects. One force which could influence planet formation is the photophoretic force. Dust grains illuminated by the central star will be unevenly heated. As gas molecules come into contact with the grain, the molecules on the hot side transfer more momentum due to their greater rebound velocities. This difference in momentum transfer results in a force which is (usually) directed away from the illumination. This may explain a feature of our own solar system, where the density of the planets decreases with increasing distance from the sun (Mercury is metallic and Earth is rocky). Metallic grains are thermally conducting and thus develop a smaller temperature gradient versus non-metals, thus more metallic grains may stay near the star while non-metallic grains are pushed outward. This study examines the photophoretic force on aggregates and isolated spheres. Numerical simulations were used to track the motion of an isolated sphere and aggregates driven by the photophoretic force. The differences in drift velocities due to photophoresis between aggregates of different sizes not only can sort the material by composition, but can also lead to increased collisions and growth.

TANAMI Source Optical Data Analysis
Miquela Stein, University of Texas at Austin

There are 89 sources in the TANAMI (Tracking Active Galactic Nuclei with Austral Milliarcsecond Interferometry) study, and there is data in both the radio and gamma ray bands. This project uses archival data to determine optical band information. With access to the MONET telescope remote optical monitoring system, we will plan future optical studies of certain sources, as determined by this study. I will discuss the preliminary results of the analysis of archival optical data and its implications.

Characterizing Galaxies out to Redshift z~4 in the DECam Survey of the SHELA/ HETDEX Field
Nicholas Watson, University of Texas at Austin

The redshift range, 1.9 < z < 3.5, is an informative period to study the evolution of galaxies. Inquiry into this period is key to understanding the effect of assembly bias (the higher merger rates in dense regions of space such as proto-clusters) and other environmental effects on the building of galaxies. Furthermore, both star formation and black hole accretion peak in this era. We aim to probe this age with data collected by four photometric surveys: the DECam ugriz survey, the Spitzer/IRAC SHELA survey, the Herschel SPIRE Stripe 82 Survey, and the NEWFIRM HETDEX survey. The surveys cover the extensive 28 sq. deg. Spitzer/HETDEX Exploratory Large Area (SHELA) field, which encompasses a comoving volume of 0.5 cubic Gpc at this redshift range, a full order of magnitude larger then previous surveys of this type. We have tested the software we are using for source detection and have begun to calibrate our results. To analyse the data, we will build spectral energy distributions (SEDs) for the detected galaxies in the region. Using the SEDs we will create catalogs of photometric redshift and stellar mass which will provide us with much of the information necessary to reveal the physics of this era.