Summer 2012 REU Project Abstracts
The Arecibo Galaxy Environment Survey òÀÓ WAPP data of the NGC 3193 region.
Roberto Rodriguez, University of Puerto Rico, Humacao
Project Supervisors: Dr. R. Minchin & Dr. R. Taylor, Arecibo Observatory
Abstract
This project will look at data taken as part of the Arecibo Galaxy Environment Survey (AGES) with the WAPP correlator. This survey is searching for galaxies by 21cm emission from neutral hydrogen gas in their interstellar media. The main dataset will consist of a datacube (of right ascension, declination, and recessional velocity) of 21cm-line spectra from the survey 20 square degrees of the NGC 3193 region, out to a redshift of z~0.06. The student will search and catalogue sources in the cubes and identify many previously undiscovered galaxies. The neutral hydrogen spectra of the sources found will be analyzed by the student in order to determine their characteristics. Galaxies found will be cross-referenced using the Virtual Astronomical Observatory in order to determine if they have counterparts that have been previously catalogued. The student will also use the VAO to access optical and infrared data, which they will download and analyze.
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The Arecibo Galaxy Environment Survey òÀÓ Mock Spectrometer data of the NGC 7448 region.
Clarissa Vazquez, University of Puerto Rico, Humacao
Project Supervisors: Dr. R. Taylor & Dr. R. Minchin, Arecibo Observatory
Abstract
This project will look at data taken as part of the Arecibo Galaxy Environment Survey (AGES) with the new Mock Spectrometer. This survey is searching for galaxies by 21cm emission from neutral hydrogen gas in their interstellar media. The main dataset will consist of a datacube (of right ascension, declination, and recessional velocity) of 21cm-line spectra from the survey of 5 square degrees of the NGC 7448 region, out to a redshift of z~0.15. The student will search and catalogue sources in the cubes and identify many previously undiscovered galaxies. The neutral hydrogen spectra of the sources found will be analyzed by the student in order to determine their characteristics. Galaxies found will be cross-referenced using the Virtual Astronomical Observatory in order to determine if they have counterparts that have been previously catalogued. The student will also use the VAO to access optical and infrared data, which they will download and analyze.
Solar activity effects on total electron content over Arecibo Observatory: Observational results versus IRI predictions.
Teresa Symons, Embry Ridle University
Project Supervisors: Christiano Garnett Marques Brum, Edvier Cabassa-Miranda & Nestor Aponte, Arecibo Observatory
Project Contributors: Eframir Franco, University of Puerto Rico, Humacao
Abstract
In this project, we are comparing the responses of the total electron content (TEC) to the solar activity variation. For this, we are using TEC data registered at the Arecibo Observatory site from 2004 to 2012. For the estimation of the solar activity, we are using the irradiances for the 0.1òÀÓ50 nm band measured by the Solar EUV Monitor onboard the SOHO for the same period. Based on these data, an empirical model was developed in order to study the variation (responses) of the TEC during the year for different conditions of solar activity. In addition, we are comparing the predictions of our empirical model with those made by the international reference ionosphere (IRI) model. Our results are discussed from the perspective of validating and upgrading the IRI model representations of the TEC for the Caribbean sector.
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Solar and season variability of the transition height over Arecibo Observatory.
Eframir Franco, University of Puerto Rico, Humacao
Project Supervisors: Christiano Garnett Marques Brum & Edvier Cabassa-Miranda, Arecibo Observatory
Project Contributors: Teresa Symons, Embry Ridle University
ABSTRACT: The topside ionosphere lies above the F2 peak and merges into the protonosphere where H+ ions dominate. The ionòÀÓelectron plasma assumes a distribution close to that appropriated to diffuse equilibrium under gravity, with departures from diffusive equilibrium arising from the effect of such factors as neutral winds and electric fields. At this region the main conversion process is the charge exchange reaction (O++HˆëO+H+) and a considerable fraction of H+ may also be produced by direct photoionization of neutral H by the solar EUV radiation of wavelengths less than 91nm, and this characteristic transfer a strong dependence of the H+ and O+ with the solar activity. The transition height of the H+ and O+ ions (ht) is an important parameter that defines the distribution of these ions in the topside ionosphere and it is defined as the altitude where the H+ and O+ concentrations are equal and marks the transition from the topside ionosphere and protonosphere and also is strongly dependent of the solar activity and season. The purpose of this work is to evaluate the responses of the topside/protonosphere over Arecibo Observatory (18.35oN, 66.75oW) based on Incoherent Scatter Radar data due to solar activity and season variations. For this reason, we analyzed the ISR data commencing from1998 through 2009, plus the UV-EUV measurements for broad wavelength range from 0.1 to 50nm by the Solar EUV Monitor aboard the Solar Heliospheric Observatory (SOHO).
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The Interstellar Media of the Luminous Infra-Red Galaxies, IC860 & Zw049.057
Yamil Nieves, Unviersity of Puerto Rico, Humacao
Project Supervisors: C.J. Salter, R.F. Minchin & T. Ghosh, Arecibo Observatory
Abstract
From a recent Arecibo 4.45-5.30 GHz survey of 20 "Arp220-like" galaxies, the molecular spectra of two objects revealed remarkably similar interstellar media to that of the prototypical Ultra-Luminous Infra-Red Galaxy (ULIRG) Arp 220. This is in terms of both composition and physical state, despite both galaxies having much lower FIR luminosities than Arp 220. Using the Double Position Switching (DPS) technique, we have now extended the spectral coverage for these two LIRGs, IC860 and Zw049.057, to include all frequencies within the range of 3.0 to 10.0 GHz.ˆà From the spectra of the two galaxies, we detect the "pre-biotic" molecules, methanimine (CH2NH) in emission, and hydrogen cyanide (HCN v2=1) in absorption. We also detect in both, formaldehyde (H2CO) in emission at 4.830 and 4.955 GHz, and hydroxyl (OH) in absorption at 4.7 and 6.0 GHz, as well as the 3.335-GHz emission line of methylidyne (CH) in Zw049.057.ˆà The detected pair of H2CO lines allows us to determine a kinetic temperature of 58 K for IC860.ˆà A number of other possible detections are being further investigated.