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Brian Espey

Feed . Journal article Empirical Modelling of Public Lighting Emission Functions Brian Espey https://doi.org/10.3390/rs13193827 Published: 24 September 2021 in Remote Sensing . Reads? 0 Downloads? 0 Abstract Cite All recommendations Study of light at night has increased in recent decades due to the recognition of its impact on the environment, potential health concerns, as well as both the financial and carbon cost of energy waste. The advent of more extensive and improved ground-based measurements together with quantifiable satellite data has revolutionised the field, and provided data to test improved theoretical models. However, “closing the loop” and finding a detailed connection between these measurements requires knowledge of the “city emission function”, the angular distribution of upwelling radiation with zenith distance. Simplified analytical functions have been superseded by more complex models involving statistical approximation of emission sources and obstructions and inversion techniques now permit the estimation of emission functions from the observed sky brightness measurements. In this paper, we present an efficient GIS-based method to model public lighting using real-world photometric data and high-resolution digital elevation maps of obstructions such as buildings and trees at a 1 m scale. We discuss the results of this work for a sample of Irish towns as well as a city area. We also compare our results to previous emission functions as well as to observed asymmetries in emission detected by satellites such as SUOMI VIIRS. ACS Style Brian R. Espey. Empirical Modelling of Public Lighting Emission Functions. Remote Sensing 2021 , 13 , 3827 . AMA Style Brian R. Espey. Empirical Modelling of Public Lighting Emission Functions. Remote Sensing. 2021; 13 (19):3827. Chicago/Turabian Style Brian R. Espey. 2021. "Empirical Modelling of Public Lighting Emission Functions." Remote Sensing 13, no. 19: 3827. Short communication Perceptions of Light Pollution and its Impacts: Results of an Irish Citizen Science Survey Andrew Coogan Michael Cleary-Gaffney Megan Finnegan Georgia McMillan Ainhoa González Brian Espey https://doi.org/10.3390/ijerph17155628 Published: 04 August 2020 in International Journal of Environmental Research and Public Health . Reads? 0 Downloads? 0 Abstract Cite All recommendations Background: Light pollution is increasingly an area of concern for health and quality of life research. Somewhat surprisingly, there are relatively few descriptions of perceptions of light pollution in the literature. The current study examined such perceptions in a Irish sample. Methods: A survey was circulated as part of a citizen science initiative of a national newspaper; the survey included questions regarding night sky brightness and the impact of light at night on sleep and animal behaviour. Complete responses from 462 respondents were analysed. Results: Urban location was, as anticipated, associated with reported brighter night skies, and public lighting was reported as the main source of light at night for urban settings, whilst neighbours’ domestic lighting was the most commonly reported source for rural settings. Respondents from rural settings were more likely to report that light at night impinged on sleep, whilst city dwellers were more likely to report recent changes in wildlife behaviour. Conclusions: Citizen science approaches may be useful in gathering data on public perceptions of light pollution and its impacts. In the current study, this perception was strongly influenced by location, highlighting the importance of assessing experiences and attitudes across a number of geographical settings. ACS Style Andrew N. Coogan; Michael Cleary-Gaffney; Megan Finnegan; Georgia McMillan; Ainhoa González; Brian Espey. Perceptions of Light Pollution and its Impacts: Results of an Irish Citizen Science Survey. International Journal of Environmental Research and Public Health 2020 , 17 , 5628 . AMA Style Andrew N. Coogan, Michael Cleary-Gaffney, Megan Finnegan, Georgia McMillan, Ainhoa González, Brian Espey. Perceptions of Light Pollution and its Impacts: Results of an Irish Citizen Science Survey. International Journal of Environmental Research and Public Health. 2020; 17 (15):5628. Chicago/Turabian Style Andrew N. Coogan; Michael Cleary-Gaffney; Megan Finnegan; Georgia McMillan; Ainhoa González; Brian Espey. 2020. "Perceptions of Light Pollution and its Impacts: Results of an Irish Citizen Science Survey." International Journal of Environmental Research and Public Health 17, no. 15: 5628. Research article Initial Irish light pollution measurements and a new Sky Quality Meter-based data logger Brian Espey Joe McCauley https://doi.org/10.1177/1477153513515508 Published: 10 January 2014 in Lighting Research & Technology . Reads? 0 Downloads? 0 Abstract Cite All recommendations In the Celtic Tiger years, Ireland underwent an explosive growth in housing and an increase in light pollution, nationally. We outline work undertaken towards the first ever ground-based survey of light pollution in the island of Ireland and illustrate this with some representative data taken between 2009 and the present. The aim of our work is to establish a database to serve as a reference to monitor future changes, to compare with in-orbit measurements, to study the potential impact on the environment and to permit the calculation of the effects of future changes in lighting usage and patterns. We also report the development of a microcontroller-based data-logging instrument based on a Unihedron Sky Quality Meter-LR detector, which can be used by amateurs or can serve as a stand-alone instrument for night-sky brightness surveys. ACS Style Brian R Espey; Joe McCauley. Initial Irish light pollution measurements and a new Sky Quality Meter-based data logger. Lighting Research & Technology 2014 , 46 , 67 -77. AMA Style Brian R Espey, Joe McCauley. Initial Irish light pollution measurements and a new Sky Quality Meter-based data logger. Lighting Research & Technology. 2014; 46 (1):67-77. Chicago/Turabian Style Brian R Espey; Joe McCauley. 2014. "Initial Irish light pollution measurements and a new Sky Quality Meter-based data logger." Lighting Research & Technology 46, no. 1: 67-77. Conference paper Winds and Chromospheres of Cool (Super-) Giants C. Crowley Brian Espey G. M. Harper J. Roche Eric Stempels https://doi.org/10.1063/1.3099101 Published: 01 January 2009 in COOL STARS, STELLAR SYSTEMS AND THE SUN: Proceedings of the 15th Cambridge Workshop on Cool Stars, Stellar Systems and the Sun . Reads? 0 Downloads? 0 Abstract Cite All recommendations We summarise the CS15 splinter session dealing with the winds and chromospheres of cool giant and supergiant stars. The motivation behind the session was to bring together various researchers in the field with the purpose of forming some important common goals for future work, as well as to hear some of the latest results. We provide an overview of the results that were presented and highlight some of the main outcomes of the discussions. ACS Style C. Crowley; Brian Espey; G. M. Harper; J. Roche; Eric Stempels. Winds and Chromospheres of Cool (Super-) Giants. COOL STARS, STELLAR SYSTEMS AND THE SUN: Proceedings of the 15th Cambridge Workshop on Cool Stars, Stellar Systems and the Sun 2009 , 1094 , 267 -274. AMA Style C. Crowley, Brian Espey, G. M. Harper, J. Roche, Eric Stempels. Winds and Chromospheres of Cool (Super-) Giants. COOL STARS, STELLAR SYSTEMS AND THE SUN: Proceedings of the 15th Cambridge Workshop on Cool Stars, Stellar Systems and the Sun. 2009; 1094 (1):267-274. Chicago/Turabian Style C. Crowley; Brian Espey; G. M. Harper; J. Roche; Eric Stempels. 2009. "Winds and Chromospheres of Cool (Super-) Giants." COOL STARS, STELLAR SYSTEMS AND THE SUN: Proceedings of the 15th Cambridge Workshop on Cool Stars, Stellar Systems and the Sun 1094, no. 1: 267-274. Conference paper Exploring the Origin of Red Giant Winds Joseph Roche Brian Espey Cian Crowley https://doi.org/10.1063/1.3099260 Published: 01 January 2009 in COOL STARS, STELLAR SYSTEMS AND THE SUN: Proceedings of the 15th Cambridge Workshop on Cool Stars, Stellar Systems and the Sun . Reads? 0 Downloads? 0 Abstract Cite All recommendations As a star cools and expands to become a red giant it will become pulsationally unstable. The amplitude tends to increase with decreasing temperature as the star ascends the red giant branch. Below around 4,000 K (Spectral Type K5III) microvariability sets in. This may have a strong impact on the pulsation‐driven mass loss history. We are studying a sample of symbiotic binaries in order to understand the mechanism of mass loss from the red giant primary. Photometric monitoring indicates small‐scale variability of around 20% over a timescale of ?30 days . This is likely related to the convective motion on the surface which may be directly or indirectly involved in providing the initial impetus to raise material and initiate the wind. Studying this convective motion and its relationship with the wind will improve our understanding of the wind’s origin. ACS Style Joseph Roche; Brian R. Espey; Cian Crowley. Exploring the Origin of Red Giant Winds. COOL STARS, STELLAR SYSTEMS AND THE SUN: Proceedings of the 15th Cambridge Workshop on Cool Stars, Stellar Systems and the Sun 2009 , 888 -891. AMA Style Joseph Roche, Brian R. Espey, Cian Crowley. Exploring the Origin of Red Giant Winds. COOL STARS, STELLAR SYSTEMS AND THE SUN: Proceedings of the 15th Cambridge Workshop on Cool Stars, Stellar Systems and the Sun. 2009; ():888-891. Chicago/Turabian Style Joseph Roche; Brian R. Espey; Cian Crowley. 2009. "Exploring the Origin of Red Giant Winds." COOL STARS, STELLAR SYSTEMS AND THE SUN: Proceedings of the 15th Cambridge Workshop on Cool Stars, Stellar Systems and the Sun , no. : 888-891. Journal article EG And:Far Ultraviolet Spectroscopic ExplorerandHubble Space TelescopeSTIS Monitoring of an Eclipsing Symbiotic Binary Cian Crowley Brian Espey Stephan R. McCandliss https://doi.org/10.1086/524127 Published: 01 March 2008 in The Astrophysical Journal . Reads? 0 Downloads? 0 Abstract Cite All recommendations We present highlights and an overview of 20FUSE andHST STIS observations of the bright symbiotic binary EG And. The main motivation behind this work is to obtain spatially resolved information on an evolved giant star in order to understand the mass-loss processes at work in these objects. The system consists of a low-luminosity white dwarf and amass-losing, nondusty M2 giant.The ultraviolet observations followthe white dwarf continuum through periodicgradualoccultationsbythewindandchromosphereof thegiant,providingauniquediagnosisofthecircum- stellargasinabsorption.Unoccultedspectradisplayhigh-ionizationfeatures,suchastheOviresonancedoublet,which is present as a variable (hourly timescales), broad wind profile, which diagnose the hot gas close to the dwarf com- ponent. Spectraobservedatstagesof partialoccultationdisplay a hostof low-ionization, narrowabsorptionlines,with transitionsobservedfromlowerenergylevelsupto ? 5eVaboveground.Thisabsorptionisduetochromospheric/wind material, with most lines due to transitions of Si ii ,P ii ,N i ,F eii ,a nd Niii, as well as heavily damped H i Lyman series features.NomolecularfeaturesareobservedinthewindaccelerationregiondespitethesensitivityofFUSEtoH2.From analysis of the ultraviolet data set, as well as optical data, we find that the dwarf radiation does not dominate the wind accelerationregionofthegiantandthatobservedthermalanddynamicwindpropertiesaremostlikelyrepresentativeof isolated red giants. Subject headinggs: binaries: symbiotic — line: identification — stars: chromospheres — stars: individual (EG And) — stars: mass loss — ultraviolet: stars ACS Style Cian Crowley; Brian Espey; Stephan R. McCandliss. EG And:Far Ultraviolet Spectroscopic ExplorerandHubble Space TelescopeSTIS Monitoring of an Eclipsing Symbiotic Binary. The Astrophysical Journal 2008 , 675 , 711 -722. AMA Style Cian Crowley, Brian Espey, Stephan R. McCandliss. EG And:Far Ultraviolet Spectroscopic ExplorerandHubble Space TelescopeSTIS Monitoring of an Eclipsing Symbiotic Binary. The Astrophysical Journal. 2008; 675 (1):711-722. Chicago/Turabian Style Cian Crowley; Brian Espey; Stephan R. McCandliss. 2008. "EG And:Far Ultraviolet Spectroscopic ExplorerandHubble Space TelescopeSTIS Monitoring of an Eclipsing Symbiotic Binary." The Astrophysical Journal 675, no. 1: 711-722. Preprint EG And: FUSE and HST/STIS Monitoring of an Eclipsing Symbiotic Binary Cian Crowley Brian Espey S. R. McCandliss Published: 12 October 2007 . Reads? 0 Downloads? 0 Abstract Cite All recommendations We present highlights and an overview of 20 FUSE and HST/STIS observations of the bright symbiotic binary EG And. The main motivation behind this work is to obtain spatially-resolved information on an evolved giant star in order to understand the mass-loss processes at work in these objects. The system consists of a low-luminosity white dwarf and a mass-losing, non-dusty M2 giant. The ultraviolet observations follow the white dwarf continuum through periodic gradual occultations by the wind and chromosphere of the giant, providing a unique diagnosis of the circumstellar gas in absorption. Unocculted spectra display high ionization features, such as the OVI resonance doublet which is present as a variable (hourly time-scales), broad wind profile, which diagnose the hot gas close to the dwarf component. Spectra observed at stages of partial occultation display a host of low-ionization, narrow, absorption lines, with transitions observed from lower energy levels up to ~5eV above ground. This absorption is due to chromospheric/wind material, with most lines due to transitions of SiII, PII, NI, FeII and NiII, as well as heavily damped HI Lyman series features. No molecular features are observed in the wind acceleration region despite the sensitivity of FUSE to molecular hydrogen. From analysis of the ultraviolet dataset, as well as optical data, we find that the dwarf radiation does not dominate the wind acceleration region of the giant, and that observed thermal and dynamic wind properties are most likely representative of isolated red giants. ACS Style Cian Crowley; B. R. Espey; S. R. McCandliss. EG And: FUSE and HST/STIS Monitoring of an Eclipsing Symbiotic Binary. 2007 , 1 . AMA Style Cian Crowley, B. R. Espey, S. R. McCandliss. EG And: FUSE and HST/STIS Monitoring of an Eclipsing Symbiotic Binary. . 2007; ():1. Chicago/Turabian Style Cian Crowley; B. R. Espey; S. R. McCandliss. 2007. "EG And: FUSE and HST/STIS Monitoring of an Eclipsing Symbiotic Binary." , no. : 1. Text High‐Ionization Forbidden Lines in the UV Spectrum of AG Draconis P. R. Young A. K. DuPree Brian Espey Scott Kenyon https://doi.org/10.1086/506584 Published: 20 October 2006 in The Astrophysical Journal . Reads? 0 Downloads? 0 Abstract Cite All recommendations High-ionization forbidden lines from Ca VII, Fe VII, Mg V, Mg VI, Mg VII, and Si VII are found in recent Hubble Space Telescope STIS ultraviolet spectra of the symbiotic star AG Draconis. These species have ionization potentials between 99 and 205 eV, which are unexpected due to the high density (≈1010 cm-3) of the AG Dra nebula. The identification of the Mg VII λλ2510, 2629 lines is the first in astrophysical or laboratory spectra, and revised rest wavelengths are suggested from the STIS spectra. Plasma diagnostics from Mg V-VII are applied, but do not provide a consistent constraint on temperature or density. A density ≥108 cm-3 is confirmed, however. The lines show double-peaked profiles with widths ≈100-160 km s-1, suggestive of an origin in an accretion disk. However, the line widths, if identified with motion in a Keplerian disk, indicate radii much smaller than sizes inferred from the line fluxes themselves. The source of these high-ionization forbidden lines remains unidentified. ACS Style P. R. Young; A. K. DuPree; Brian Espey; Scott Kenyon. High‐Ionization Forbidden Lines in the UV Spectrum of AG Draconis. The Astrophysical Journal 2006 , 650 , 1091 -1095. AMA Style P. R. Young, A. K. DuPree, Brian Espey, Scott Kenyon. High‐Ionization Forbidden Lines in the UV Spectrum of AG Draconis. The Astrophysical Journal. 2006; 650 (2):1091-1095. Chicago/Turabian Style P. R. Young; A. K. DuPree; Brian Espey; Scott Kenyon. 2006. "High‐Ionization Forbidden Lines in the UV Spectrum of AG Draconis." The Astrophysical Journal 650, no. 2: 1091-1095. Journal article A “Combination Nova” Outburst in Z Andromedae: Nuclear Shell Burning Triggered by a Disk Instability J. L. Sokoloski Scott Kenyon Brian Espey [...] Charles D. Keyes S. R. McCandliss Albert Kong J. P. Aufdenberg A. V. Filippenko W. Li C. Brocksopp Christian R. Kaiser P. A. Charles M. P. Rupen R. P. S. Stone show less https://doi.org/10.1086/498206 Published: 10 January 2006 in The Astrophysical Journal . Reads? 0 Downloads? 0 Abstract Cite All recommendations We describe observational evidence for a new kind of interacting-binary-star outburst that involves both an accretion instability and an increase in thermonuclear shell burning on the surface of an accreting white dwarf. We refer to this new type of eruption as a combination nova. In late 2000, the prototypical symbiotic star Z Andromedae brightened by roughly two magnitudes in the optical. We observed the outburst in the radio with the VLA and MERLIN, in the optical both photometrically and spectroscopically, in the far ultraviolet with FUSE, and in the X-rays with both Chandra and XMM. The two-year-long event had three distinct stages. During the first stage, the optical rise closely resembled an earlier, small outburst that was caused by an accretion-disk instability. In the second stage, the hot component ejected an optically thick shell of material. In the third stage, the shell cleared to reveal a white dwarf whose luminosity remained on the order of 10^4 Lsun for approximately one year. The eruption was thus too energetic to have been powered by accretion alone. We propose that the initial burst of accretion was large enough to trigger enhanced nuclear burning on the surface of the white dwarf and the ejection of an optically thick shell of material. This outburst therefore combined elements of both a dwarf nova and a classical nova. Our results have implications for the long-standing problem of producing shell flashes with short recurrence times on low-mass white dwarfs in symbiotic stars ACS Style J. L. Sokoloski; Scott Kenyon; Brian Espey; Charles D. Keyes; S. R. McCandliss; Albert Kong; J. P. Aufdenberg; A. V. Filippenko; W. Li; C. Brocksopp; Christian R. Kaiser; P. A. Charles; M. P. Rupen; R. P. S. Stone. A “Combination Nova” Outburst in Z Andromedae: Nuclear Shell Burning Triggered by a Disk Instability. The Astrophysical Journal 2006 , 636 , 1002 -1019. AMA Style J. L. Sokoloski, Scott Kenyon, Brian Espey, Charles D. Keyes, S. R. McCandliss, Albert Kong, J. P. Aufdenberg, A. V. Filippenko, W. Li, C. Brocksopp, Christian R. Kaiser, P. A. Charles, M. P. Rupen, R. P. S. Stone. A “Combination Nova” Outburst in Z Andromedae: Nuclear Shell Burning Triggered by a Disk Instability. The Astrophysical Journal. 2006; 636 (2):1002-1019. Chicago/Turabian Style J. L. Sokoloski; Scott Kenyon; Brian Espey; Charles D. Keyes; S. R. McCandliss; Albert Kong; J. P. Aufdenberg; A. V. Filippenko; W. Li; C. Brocksopp; Christian R. Kaiser; P. A. Charles; M. P. Rupen; R. P. S. Stone. 2006. "A “Combination Nova” Outburst in Z Andromedae: Nuclear Shell Burning Triggered by a Disk Instability." The Astrophysical Journal 636, no. 2: 1002-1019. Preprint A "Combination Nova" Outburst in Z Andromedae: Nuclear Shell Burning Triggered by a Disk Instability J. L. Sokoloski S. J. Kenyon Brian Espey [...] Charles D. Keyes S. R. McCandliss A. K. H. Kong J. P. Aufdenberg A. V. Filippenko W. Li C. Brocksopp Christian R. Kaiser P. A. Charles M. P. Rupen R. P. S. Stone show less Published: 21 September 2005 . Reads? 0 Downloads? 0 Abstract Cite All recommendations We describe observational evidence for a new kind of interacting-binary-star outburst that involves both an accretion instability and an increase in thermonuclear shell burning on the surface of an accreting white dwarf. We refer to this new type of eruption as a combination nova. In late 2000, the prototypical symbiotic star Z Andromedae brightened by roughly two magnitudes in the optical. We observed the outburst in the radio with the VLA and MERLIN, in the optical both photometrically and spectroscopically, in the far ultraviolet with FUSE, and in the X-rays with both Chandra and XMM. The two-year-long event had three distinct stages. During the first stage, the optical rise closely resembled an earlier, small outburst that was caused by an accretion-disk instability. In the second stage, the hot component ejected an optically thick shell of material. In the third stage, the shell cleared to reveal a white dwarf whose luminosity remained on the order of 10^4 Lsun for approximately one year. The eruption was thus too energetic to have been powered by accretion alone. We propose that the initial burst of accretion was large enough to trigger enhanced nuclear burning on the surface of the white dwarf and the ejection of an optically thick shell of material. This outburst therefore combined elements of both a dwarf nova and a classical nova. Our results have implications for the long-standing problem of producing shell flashes with short recurrence times on low-mass white dwarfs in symbiotic stars. ACS Style J. L. Sokoloski; S. J. Kenyon; B. R. Espey; Charles D. Keyes; S. R. McCandliss; A. K. H. Kong; J. P. Aufdenberg; A. V. Filippenko; W. Li; C. Brocksopp; Christian R. Kaiser; P. A. Charles; M. P. Rupen; R. P. S. Stone. A "Combination Nova" Outburst in Z Andromedae: Nuclear Shell Burning Triggered by a Disk Instability. 2005 , 1 . AMA Style J. L. Sokoloski, S. J. Kenyon, B. R. Espey, Charles D. Keyes, S. R. McCandliss, A. K. H. Kong, J. P. Aufdenberg, A. V. Filippenko, W. Li, C. Brocksopp, Christian R. Kaiser, P. A. Charles, M. P. Rupen, R. P. S. Stone. A "Combination Nova" Outburst in Z Andromedae: Nuclear Shell Burning Triggered by a Disk Instability. . 2005; ():1. Chicago/Turabian Style J. L. Sokoloski; S. J. Kenyon; B. R. Espey; Charles D. Keyes; S. R. McCandliss; A. K. H. Kong; J. P. Aufdenberg; A. V. Filippenko; W. Li; C. Brocksopp; Christian R. Kaiser; P. A. Charles; M. P. Rupen; R. P. S. Stone. 2005. "A "Combination Nova" Outburst in Z Andromedae: Nuclear Shell Burning Triggered by a Disk Instability." , no. : 1. Text Far Ultraviolet Spectroscopic ExplorerObservations of the Symbiotic Star AG Draconis P. R. Young A. K. DuPree Brian Espey Scott Kenyon T. B. Ake https://doi.org/10.1086/426045 Published: 10 January 2005 in The Astrophysical Journal . Reads? 0 Downloads? 0 Abstract Cite All recommendations Spectra of the bright symbiotic star AG Draconis (BD +67°922) in the wavelength range 905-1187 ? obtained with the Far Ultraviolet Spectroscopic Explorer (FUSE) are presented. The spectra show a number of narrow, nebular emission lines, together with a uniform continuum from the hot component of the system, and numerous interstellar absorption lines. We infer the existence of Ne VIII in the AG Dra nebula through the identification of the Ne VII λ973.3 recombination line. The emission-line spectrum is dominated by intense lines of O VI but also shows weaker lines from highly ionized ions including Ne V, Ne VI, S IV, and S VI. Members of the He II Balmer series can be identified up to n = 20. Lines of Fe II and Fe III fluoresced by O VI λ1032 are identified at wavelengths 1141.172 and 1142.429 ?, respectively. The emission lines are shown to be produced in a plasma with an electron temperature of 20,000-30,000 K, photoionized by the white dwarf. The Ne VI λ997/λ999 ratio shows that this ion and all others except perhaps Ne VII are formed at least 300 white dwarf radii from the white dwarf. Revised wavelengths for the Ne V 2s22p23P0,1-2s2p35S2 and Ne VI 2s22p 2P-2s2p24P transitions are published. ACS Style P. R. Young; A. K. DuPree; Brian Espey; Scott Kenyon; T. B. Ake. Far Ultraviolet Spectroscopic ExplorerObservations of the Symbiotic Star AG Draconis. The Astrophysical Journal 2005 , 618 , 891 -907. AMA Style P. R. Young, A. K. DuPree, Brian Espey, Scott Kenyon, T. B. Ake. Far Ultraviolet Spectroscopic ExplorerObservations of the Symbiotic Star AG Draconis. The Astrophysical Journal. 2005; 618 (2):891-907. Chicago/Turabian Style P. R. Young; A. K. DuPree; Brian Espey; Scott Kenyon; T. B. Ake. 2005. "Far Ultraviolet Spectroscopic ExplorerObservations of the Symbiotic Star AG Draconis." The Astrophysical Journal 618, no. 2: 891-907. Article The O IV and S IV intercombination lines in the ultraviolet spectra of astrophysical sources F. P. Keenan S. Ahmed Tomas Brage [...] J. G. Doyle Brian Espey K. M. Exter A. Hibbert M. T. C. Keenan Maria Madjarska M. Mathioudakis D. L. Pollacco show less https://doi.org/10.1046/j.1365-8711.2002.05988.x Published: 11 December 2002 in Monthly Notices of the Royal Astronomical Society . Reads? 0 Downloads? 0 Abstract Cite All recommendations New electron density diagnostic line ratios are presented for the O iv 2s22p 2—2s2p24P and S iv 3s23p 2—3s3p24P intercombination lines around 1400?. A comparison of these with observational data for the symbiotic star RR Telescopii (RR Tel), obtained with the Space Telescope Imaging Spectrograph (STIS), reveals generally very good agreement between theory and observation. However the S iv2P3/2–4P1/2 transition at 1423.824? is found to be blended with an unknown feature at 1423.774 ?. The linewidth for the latter indicates that the feature arises from a species with a large ionization potential. In addition, the S iv2P1/2–4P3/2 transition at 1398.044 ? is identified for the first time (to our knowledge) in an astrophysical source other than the Sun, and an improved wavelength of 1397.166 ? is measured for the O iv2P1/2–4P3/2 line. The O iv and S iv line ratios in a sunspot plume spectrum, obtained with the Solar Ultraviolet Measurements of the Emitted Radiation (SUMER) instrument on the Solar and Heliospheric Observatory, are found to be consistent, and remove discrepancies noted in previous comparisons of these two ions. ACS Style F. P. Keenan; S. Ahmed; Tomas Brage; J. G. Doyle; Brian Espey; K. M. Exter; A. Hibbert; M. T. C. Keenan; Maria Madjarska; M. Mathioudakis; D. L. Pollacco. The O IV and S IV intercombination lines in the ultraviolet spectra of astrophysical sources. Monthly Notices of the Royal Astronomical Society 2002 , 337 , 901 -909. AMA Style F. P. Keenan, S. Ahmed, Tomas Brage, J. G. Doyle, Brian Espey, K. M. Exter, A. Hibbert, M. T. C. Keenan, Maria Madjarska, M. Mathioudakis, D. L. Pollacco. The O IV and S IV intercombination lines in the ultraviolet spectra of astrophysical sources. Monthly Notices of the Royal Astronomical Society. 2002; 337 (3):901-909. Chicago/Turabian Style F. P. Keenan; S. Ahmed; Tomas Brage; J. G. Doyle; Brian Espey; K. M. Exter; A. Hibbert; M. T. C. Keenan; Maria Madjarska; M. Mathioudakis; D. L. Pollacco. 2002. "The O IV and S IV intercombination lines in the ultraviolet spectra of astrophysical sources." Monthly Notices of the Royal Astronomical Society 337, no. 3: 901-909. Journal article Emission lines of [K V] in the optical spectra of gaseous nebulae F. P. Keenan L. H. Aller Brian Espey [...] Katrina Exter S. Hyung M. T. C. Keenan D. L. Pollacco R. S. I. Ryans show less https://doi.org/10.1073/pnas.062032299 Published: 19 March 2002 in Proceedings of the National Academy of Sciences . Reads? 0 Downloads? 0 Abstract Cite All recommendations Recent R-matrix calculations of electron impact excitation rates in K v are used to derive the nebular emission line ratio R = I(4122.6 A)/I(4163.3 A) as a function of electron density (N(e)). This ratio is found to be very sensitive to changes in N(e) over the density range 10(3) to 10(6) cm(-3), but does not vary significantly with electron temperature, and hence in principle should provide an excellent optical N(e) diagnostic for the high-excitation zones of nebulae. The observed value of R for the planetary nebula NGC 7027, measured from a spectrum obtained with the Hamilton Echelle spectrograph on the 3-m Shane Telescope, implies a density in excellent agreement with that derived from [Ne iv], formed in the same region of the nebula as [K v]. This observation provides observational support for the accuracy of the theoretical [K v] line ratios, and hence the atomic data on which they are based. However, the analysis of a high-resolution spectrum of the symbiotic star RR Telescopii, obtained with the University College London Echelle Spectrograph on the 3.9-m Anglo-Australian Telescope, reveals that the [K v] 4122.6 A line in this object is badly blended with Fe ii 4122.6 A. Hence, the [K v] diagnostic may not be used for astrophysical sources that show a strong Fe ii emission line spectrum. ACS Style F. P. Keenan; L. H. Aller; Brian Espey; Katrina Exter; S. Hyung; M. T. C. Keenan; D. L. Pollacco; R. S. I. Ryans. Emission lines of [K V] in the optical spectra of gaseous nebulae. Proceedings of the National Academy of Sciences 2002 , 99 , 4152 -4155. AMA Style F. P. Keenan, L. H. Aller, Brian Espey, Katrina Exter, S. Hyung, M. T. C. Keenan, D. L. Pollacco, R. S. I. Ryans. Emission lines of [K V] in the optical spectra of gaseous nebulae. Proceedings of the National Academy of Sciences. 2002; 99 (7):4152-4155. Chicago/Turabian Style F. P. Keenan; L. H. Aller; Brian Espey; Katrina Exter; S. Hyung; M. T. C. Keenan; D. L. Pollacco; R. S. I. Ryans. 2002. "Emission lines of [K V] in the optical spectra of gaseous nebulae." Proceedings of the National Academy of Sciences 99, no. 7: 4152-4155. Preprint Outbursts of Classical Symbiotics: Multi-Wavelength Observations of the 2000-2001 Outburst of Z Andromedae J. L. Sokoloski S. J. Kenyon A. K. H. Kong [...] P. A. Charles C. R. Kaiser N. Seymour Brian Espey C. D. Keyes S. R. McCandliss A. V. Filippenko W. Li G. G. Pooley C. Brocksopp R. P. S. Stone show less Published: 02 October 2001 . Reads? 0 Downloads? 0 Abstract Cite All recommendations We describe the first results from a program of multi-wavelength monitoring of symbiotic binary stars in outburst. The prototypical symbiotic star Z Andromedae was observed extensively at radio, optical, far-UV, and X-ray wavelengths during its current (ongoing) outburst. These observations provide evidence for an initial obscuration or the source of ionizing radiation by an optically thick shell of material, outflow with velocities of 100s of km/s, plus collisional excitation and shock heating of the red-giant wind. In addition, the optical light curve reveals variability on time scales as short as days on both the rise to and decline from optical maximum. ACS Style J. L. Sokoloski; S. J. Kenyon; A. K. H. Kong; P. A. Charles; C. R. Kaiser; N. Seymour; B. R. Espey; C. D. Keyes; S. R. McCandliss; A. V. Filippenko; W. Li; G. G. Pooley; C. Brocksopp; R. P. S. Stone. Outbursts of Classical Symbiotics: Multi-Wavelength Observations of the 2000-2001 Outburst of Z Andromedae. 2001 , 1 . AMA Style J. L. Sokoloski, S. J. Kenyon, A. K. H. Kong, P. A. Charles, C. R. Kaiser, N. Seymour, B. R. Espey, C. D. Keyes, S. R. McCandliss, A. V. Filippenko, W. Li, G. G. Pooley, C. Brocksopp, R. P. S. Stone. Outbursts of Classical Symbiotics: Multi-Wavelength Observations of the 2000-2001 Outburst of Z Andromedae. . 2001; ():1. Chicago/Turabian Style J. L. Sokoloski; S. J. Kenyon; A. K. H. Kong; P. A. Charles; C. R. Kaiser; N. Seymour; B. R. Espey; C. D. Keyes; S. R. McCandliss; A. V. Filippenko; W. Li; G. G. Pooley; C. Brocksopp; R. P. S. Stone. 2001. "Outbursts of Classical Symbiotics: Multi-Wavelength Observations of the 2000-2001 Outburst of Z Andromedae." , no. : 1. Text Contemporaneous Ultraviolet and Optical Observations of Direct and Raman‐scattered OviLines in Symbiotic Stars Jennifer J. Birriel Brian Espey Regina E. Schulte‐Ladbeck https://doi.org/10.1086/317851 Published: 20 December 2000 in The Astrophysical Journal . Reads? 0 Downloads? 0 Abstract Cite All recommendations Symbiotic stars are binary systems consisting of a hot star, typically a white dwarf, and a cool giant companion. The wind from the cool star is ionized by the radiation from the hot star, resulting in the characteristic combination of sharp nebular emission lines and stellar molecular absorption bands in the optical spectrum. Most of the emission lines are readily identifiable with common ions. However, two strong, broad emission lines at 6825 and 7082 ? defied identification with known atoms and ions. In 1989 Schmid made the case that these long unidentified emission lines resulted from the Raman scattering of the O VI resonance photons at 1032, 1038 ? by neutral hydrogen. We present contemporaneous far-UV and optical observations of direct and Raman-scattered O VI lines for nine symbiotic stars obtained with the Hopkins Ultraviolet Telescope (Astro-2) and various ground-based optical telescopes. The O VI emission lines are present in every instance in which the λλ6825, 7082 lines are present, in support of the Schmid Raman-scattering model. We calculate the scattering efficiencies and discuss the results in terms of the Raman-scattering model. Additionally, we measure the flux of the Fe II fluorescence line at 1776 ?, which is excited by the O VI line at 1032 ?, and calculate the first estimates of the conversion efficiencies for this process. ACS Style Jennifer J. Birriel; Brian R. Espey; Regina E. Schulte‐Ladbeck. Contemporaneous Ultraviolet and Optical Observations of Direct and Raman‐scattered OviLines in Symbiotic Stars. The Astrophysical Journal 2000 , 545 , 1020 -1033. AMA Style Jennifer J. Birriel, Brian R. Espey, Regina E. Schulte‐Ladbeck. Contemporaneous Ultraviolet and Optical Observations of Direct and Raman‐scattered OviLines in Symbiotic Stars. The Astrophysical Journal. 2000; 545 (2):1020-1033. Chicago/Turabian Style Jennifer J. Birriel; Brian R. Espey; Regina E. Schulte‐Ladbeck. 2000. "Contemporaneous Ultraviolet and Optical Observations of Direct and Raman‐scattered OviLines in Symbiotic Stars." The Astrophysical Journal 545, no. 2: 1020-1033. Text The Hubble Deep Field South: Formulation of the Observing Campaign Robert E. Williams Stefi Baum Louis E. Bergeron [...] Nicholas Bernstein Brett S. Blacker Brian J. Boyle Thomas Brown C. Marcella Carollo Stefano Casertano Riccardo Covarrubias Duília F. De Mello Mark E. Dickinson Brian Espey Henry C. Ferguson Andrew Fruchter Jonathan P. Gardner Anne Gonnella Jeffrey Hayes Paul C. Hewett Inger Heyer Richard Hook Mike Irwin Daniel Jones Mary Elizabeth Kaiser Zolt Levay Andy Lubenow Ray A. Lucas Jennifer Mack John W. MacKenty Piero Madau Russell B. Makidon Crystal L. Martin Lisa Mazzuca Maximilian Mutchler Ray Norris Beth Perriello M. M. Phillips Marc Postman Patricia Royle Kailash Sahu Sandra Savaglio Alison Sherwin T. Ed Smith Massimo Stiavelli Nicholas B. Suntzeff Harry I. Teplitz Roeland van der Marel Alistair R. Walker Ray J. Weymann Michael S. Wiggs Gerard M. Williger Jennifer Wilson Norbert Zacharias David R. Zurek show less https://doi.org/10.1086/316854 Published: 01 December 2000 in The Astronomical Journal . Reads? 0 Downloads? 0 Abstract Cite All recommendations Deep, multiband observations of high Galactic latitude fields are an essential tool for studying topics ranging from Galactic structure to extragalactic background radiation. The Hubble Deep Field (HDF-N) observations obtained in 1995 December established a standard for such narrow, deep surveys. The field has been extensively analyzed by a variety of groups and has been widely studied with imaging and spectroscopy over wavelengths ranging from 10-3 to 2 × 105 μm. We describe here a second deep field campaign (HDF-S), this time in the southern hemisphere, undertaken by the Hubble Space Telescope (HST) in 1998 October in a program very similar to the northern Hubble Deep Field. Imaging and spectroscopy of three adjacent fields in the southern continuous viewing zone were obtained simultaneously for 150 orbits, and a mosaic of flanking fields was imaged for 27 additional orbits. Two important features of the HDF-S distinguish it from the HDF-N: the campaign included parallel observations by the three main HST instruments—WFPC2, STIS, and NICMOS—and the HDF-S location was selected to place a bright z = 2.24 quasar in the STIS field of view. The HDF-S observations consist of WFPC2 images in filters close to U, B, V, and I, a deep STIS image of the field surrounding the quasar, spectroscopy of the quasar with STIS from 1150 to 3560 ?, and deep imaging of an adjacent field with NICMOS camera 3 at 1.1, 1.6, and 2.2 μm. All of the HDF-S data were fully reduced and made publicly available within 2 months of the observations, and we describe here the selection of the fields and the observing strategy that was employed. Detailed descriptions of the data and the reduction techniques for each field, together with the corresponding source catalogs, appear in separate papers. ACS Style Robert E. Williams; Stefi Baum; Louis E. Bergeron; Nicholas Bernstein; Brett S. Blacker; Brian J. Boyle; Thomas Brown; C. Marcella Carollo; Stefano Casertano; Riccardo Covarrubias; Duília F. De Mello; Mark E. Dickinson; Brian Espey; Henry C. Ferguson; Andrew Fruchter; Jonathan P. Gardner; Anne Gonnella; Jeffrey Hayes; Paul C. Hewett; Inger Heyer; Richard Hook; Mike Irwin; Daniel Jones; Mary Elizabeth Kaiser; Zolt Levay; Andy Lubenow; Ray A. Lucas; Jennifer Mack; John W. MacKenty; Piero Madau; Russell B. Makidon; Crystal L. Martin; Lisa Mazzuca; Maximilian Mutchler; Ray Norris; Beth Perriello; M. M. Phillips; Marc Postman; Patricia Royle; Kailash Sahu; Sandra Savaglio; Alison Sherwin; T. Ed Smith; Massimo Stiavelli; Nicholas B. Suntzeff; Harry I. Teplitz; Roeland van der Marel; Alistair R. Walker; Ray J. Weymann; Michael S. Wiggs; Gerard M. Williger; Jennifer Wilson; Norbert Zacharias; David R. Zurek. The Hubble Deep Field South: Formulation of the Observing Campaign. The Astronomical Journal 2000 , 120 , 2735 -2746. AMA Style Robert E. Williams, Stefi Baum, Louis E. Bergeron, Nicholas Bernstein, Brett S. Blacker, Brian J. Boyle, Thomas Brown, C. Marcella Carollo, Stefano Casertano, Riccardo Covarrubias, Duília F. De Mello, Mark E. Dickinson, Brian Espey, Henry C. Ferguson, Andrew Fruchter, Jonathan P. Gardner, Anne Gonnella, Jeffrey Hayes, Paul C. Hewett, Inger Heyer, Richard Hook, Mike Irwin, Daniel Jones, Mary Elizabeth Kaiser, Zolt Levay, Andy Lubenow, Ray A. Lucas, Jennifer Mack, John W. MacKenty, Piero Madau, Russell B. Makidon, Crystal L. Martin, Lisa Mazzuca, Maximilian Mutchler, Ray Norris, Beth Perriello, M. M. Phillips, Marc Postman, Patricia Royle, Kailash Sahu, Sandra Savaglio, Alison Sherwin, T. Ed Smith, Massimo Stiavelli, Nicholas B. Suntzeff, Harry I. Teplitz, Roeland van der Marel, Alistair R. Walker, Ray J. Weymann, Michael S. Wiggs, Gerard M. Williger, Jennifer Wilson, Norbert Zacharias, David R. Zurek. The Hubble Deep Field South: Formulation of the Observing Campaign. The Astronomical Journal. 2000; 120 (6):2735-2746. Chicago/Turabian Style Robert E. Williams; Stefi Baum; Louis E. Bergeron; Nicholas Bernstein; Brett S. Blacker; Brian J. Boyle; Thomas Brown; C. Marcella Carollo; Stefano Casertano; Riccardo Covarrubias; Duília F. De Mello; Mark E. Dickinson; Brian Espey; Henry C. Ferguson; Andrew Fruchter; Jonathan P. Gardner; Anne Gonnella; Jeffrey Hayes; Paul C. Hewett; Inger Heyer; Richard Hook; Mike Irwin; Daniel Jones; Mary Elizabeth Kaiser; Zolt Levay; Andy Lubenow; Ray A. Lucas; Jennifer Mack; John W. MacKenty; Piero Madau; Russell B. Makidon; Crystal L. Martin; Lisa Mazzuca; Maximilian Mutchler; Ray Norris; Beth Perriello; M. M. Phillips; Marc Postman; Patricia Royle; Kailash Sahu; Sandra Savaglio; Alison Sherwin; T. Ed Smith; Massimo Stiavelli; Nicholas B. Suntzeff; Harry I. Teplitz; Roeland van der Marel; Alistair R. Walker; Ray J. Weymann; Michael S. Wiggs; Gerard M. Williger; Jennifer Wilson; Norbert Zacharias; David R. Zurek. 2000. "The Hubble Deep Field South: Formulation of the Observing Campaign." The Astronomical Journal 120, no. 6: 2735-2746. Text The Hubble Deep Field South: STIS Imaging Jonathan P. Gardner Stefi A. Baum Thomas Brown [...] C. Marcella Carollo Jennifer Christensen Ilana Dashevsky Mark E. Dickinson Brian Espey Henry C. Ferguson Andrew Fruchter Anne M. Gonnella Rosa Amelia Gonzalez-Lopezlira Richard N. Hook Mary Elizabeth Kaiser Crystal L. Martin Kailash C. Sahu Sandra Savaglio T. Ed Smith Harry I. Teplitz Robert E. Williams Jennifer Wilson show less https://doi.org/10.1086/301215 Published: 01 February 2000 in The Astronomical Journal . Reads? 0 Downloads? 0 Abstract Cite All recommendations We present the imaging observations made with the Space Telescope Imaging Spectrograph (STIS) of the Hubble Deep Field South. The field was imaged in four bandpasses: a clear CCD bandpass for 156 ks, a long-pass filter for 22–25 ks pixel-1 typical exposure, a near-UV bandpass for 23 ks, and a far-UV bandpass for 52 ks. The clear, visible image is the deepest observation ever made in the UV-optical wavelength region, reaching a 10 σ AB magnitude of 29.4 for an object of area 0.2 arcsec2. The field contains QSO J2233-606, the target of the STIS spectroscopy, and extends 50'' × 50'' for the visible images, and 25'' × 25'' for the ultraviolet images. We present the images, catalog of objects, and galaxy counts obtained in the field. ACS Style Jonathan P. Gardner; Stefi A. Baum; Thomas Brown; C. Marcella Carollo; Jennifer Christensen; Ilana Dashevsky; Mark E. Dickinson; Brian Espey; Henry C. Ferguson; Andrew Fruchter; Anne M. Gonnella; Rosa Amelia Gonzalez-Lopezlira; Richard N. Hook; Mary Elizabeth Kaiser; Crystal L. Martin; Kailash C. Sahu; Sandra Savaglio; T. Ed Smith; Harry I. Teplitz; Robert E. Williams; Jennifer Wilson. The Hubble Deep Field South: STIS Imaging. The Astronomical Journal 2000 , 119 , 486 -508. AMA Style Jonathan P. Gardner, Stefi A. Baum, Thomas Brown, C. Marcella Carollo, Jennifer Christensen, Ilana Dashevsky, Mark E. Dickinson, Brian Espey, Henry C. Ferguson, Andrew Fruchter, Anne M. Gonnella, Rosa Amelia Gonzalez-Lopezlira, Richard N. Hook, Mary Elizabeth Kaiser, Crystal L. Martin, Kailash C. Sahu, Sandra Savaglio, T. Ed Smith, Harry I. Teplitz, Robert E. Williams, Jennifer Wilson. The Hubble Deep Field South: STIS Imaging. The Astronomical Journal. 2000; 119 (2):486-508. Chicago/Turabian Style Jonathan P. Gardner; Stefi A. Baum; Thomas Brown; C. Marcella Carollo; Jennifer Christensen; Ilana Dashevsky; Mark E. Dickinson; Brian Espey; Henry C. Ferguson; Andrew Fruchter; Anne M. Gonnella; Rosa Amelia Gonzalez-Lopezlira; Richard N. Hook; Mary Elizabeth Kaiser; Crystal L. Martin; Kailash C. Sahu; Sandra Savaglio; T. Ed Smith; Harry I. Teplitz; Robert E. Williams; Jennifer Wilson. 2000. "The Hubble Deep Field South: STIS Imaging." The Astronomical Journal 119, no. 2: 486-508. Text Spatially Resolved Hopkins Ultraviolet Telescope Spectra of NGC 1068 John P. Grimes Gerard Kriss Brian Espey https://doi.org/10.1086/307957 Published: 20 November 1999 in The Astrophysical Journal . Reads? 0 Downloads? 0 Abstract Cite All recommendations We present spatially resolved far-ultraviolet spectra (912-1840 ?) of NGC 1068 obtained using the Hopkins Ultraviolet Telescope (HUT) during the 1995 March Astro-2 mission. Three spectra of this prototypical Seyfert 2 galaxy were obtained through a 12'' diameter aperture centered on different locations near the nucleus. The first pointing (A1) was centered west of the optical nucleus; the nucleus was on the eastern edge of the aperture. The second (A2) was centered southwest of the optical nucleus with the nucleus well inside the aperture. The third (B) was centered on the ionization cone, with the nucleus on the southwestern edge of the aperture. While all three aperture locations have spectra similar to the Astro-1 observations of Kriss et al., these new spatially resolved observations localize the source of the far-UV line and continuum emission. The ionization cone (location B) has both brighter emission lines and continuum than the nuclear region (location A2). Position A1 is fainter than either A2 or B in both lines and continuum. The far-UV emission lines observed with HUT have a spatial distribution that most closely resembles that of [O III] λ5007 but appear to be more extended and offset to the northeast along the axis of the radio jet. This supports the previous conclusion of Kriss et al. that the bright C III λ977 and N III λ991 arises in shock-heated gas. The UV continuum radiation has a more extended spatial distribution than the line-emitting gas. At wavelengths longward of 1200 ?, the inferred continuum distribution is consistent with that seen in archival Hubble Space Telescope WFPC2 images through filter F218W, and it appears to contain a substantial contribution from starlight. At wavelengths shorter than 1200 ?, the UV continuum becomes more concentrated in a region matching the location and shape of the UV line radiation, consistent with nuclear flux scattered by a combination of the electron scattering mirror and the northeast dust cloud. ACS Style John P. Grimes; Gerard Kriss; Brian R. Espey. Spatially Resolved Hopkins Ultraviolet Telescope Spectra of NGC 1068. The Astrophysical Journal 1999 , 526 , 130 -140. AMA Style John P. Grimes, Gerard Kriss, Brian R. Espey. Spatially Resolved Hopkins Ultraviolet Telescope Spectra of NGC 1068. The Astrophysical Journal. 1999; 526 (1):130-140. Chicago/Turabian Style John P. Grimes; Gerard Kriss; Brian R. Espey. 1999. "Spatially Resolved Hopkins Ultraviolet Telescope Spectra of NGC 1068." The Astrophysical Journal 526, no. 1: 130-140. Article [Al II] in the ultraviolet spectrum of the symbiotic star RR Telescopii F. P. Keenan Brian Espey M. Mathioudakis [...] K. M. Aggarwal F. L. Crawford W. A. Feibelman F. C. McKenna show less https://doi.org/10.1046/j.1365-8711.1999.02823.x Published: 11 October 1999 in Monthly Notices of the Royal Astronomical Society . Reads? 0 Downloads? 0 Abstract Cite All recommendations An inspection of a GHRS/HST spectrum of the symbiotic star RR Telescopii reveals the presence of the [Al ii] 3s21S — 3s3p 3P2 line at a vacuum wavelength of 2661.06±0.08 ?, 8.89±0.08 ? away from the Al ii] 3s21S — 3s3p 3P1 intercombination transition at 2669.95 ?, in good agreement with the theoretical prediction of Δλ=8.80 ?. We also find that the Al ii] line profile is asymmetric, showing a strong low-density component with a weak high-density wing, redshifted by 30 km s?1, in agreement with the findings of Schild & Schmid, which were based on optical observations. Our measurement of the emission-line ratio RI(2661.06 ?)/I(2669.95 ?)=0.027±0.003 implies log Ne=5.8±0.2, in good agreement with the densities found from other ions, such as Si iii. These results provide strong evidence that we have detected the [Al ii] line, the first time (to our knowledge) that this feature has been reliably identified in an astrophysical or laboratory spectrum. ACS Style F. P. Keenan; Brian Espey; M. Mathioudakis; K. M. Aggarwal; F. L. Crawford; W. A. Feibelman; F. C. McKenna. [Al II] in the ultraviolet spectrum of the symbiotic star RR Telescopii. Monthly Notices of the Royal Astronomical Society 1999 , 309 , 195 -198. AMA Style F. P. Keenan, Brian Espey, M. Mathioudakis, K. M. Aggarwal, F. L. Crawford, W. A. Feibelman, F. C. McKenna. [Al II] in the ultraviolet spectrum of the symbiotic star RR Telescopii. Monthly Notices of the Royal Astronomical Society. 1999; 309 (1):195-198. Chicago/Turabian Style F. P. Keenan; Brian Espey; M. Mathioudakis; K. M. Aggarwal; F. L. Crawford; W. A. Feibelman; F. C. McKenna. 1999. "[Al II] in the ultraviolet spectrum of the symbiotic star RR Telescopii." Monthly Notices of the Royal Astronomical Society 309, no. 1: 195-198. Text Final Astro‐2 Calibration of the Hopkins Ultraviolet Telescope Jeffrey W. Kruk Thomas M. Brown Arthur F. Davidsen Brian Espey David S. Finley Gerard Kriss https://doi.org/10.1086/313217 Published: 01 May 1999 in The Astrophysical Journal Supplement Series . Reads? 0 Downloads? 0 Abstract Cite All recommendations We present the final calibration of the Hopkins Ultraviolet Telescope (HUT) for its flight during the Astro-2 space shuttle mission in 1995 March. Aspects of mission operations and instrument performance that affect data quality are described in detail, as are the data reduction procedures applied to the archived data. The sensitivity calibration is defined by a comparison between synthetic spectra and observations obtained in flight of the hot DA white dwarfs HZ 43, GD 71, GD 153, and G191-B2B; the synthetic spectra were calculated by D. Koester using model parameters derived from fits to ground-based spectra. The resulting flux-calibrated spectra for these stars differ from their respective model predictions by less than 3% at all wavelengths, except at the cores of the Lyman lines where the observed line profiles are shallower than the predicted profiles. As an additional consistency check, the HUT spectrum of BD +75°325 was found to differ from the Hubble Space Telescope Faint Object Spectrograph spectrum by at most 5% in the region of overlap. The wavelength scale and spectral resolution were calibrated by observations of symbiotic stars and of the coronal star α Aur. The spectral resolution was found to vary from 1.8 to roughly 4.5 ?, depending on wavelength and on the instrument configuration. The internal consistency of the HUT calibration provides a new and important test of white dwarf model atmospheres, as the predicted stellar spectra are more sensitive to changes in model parameters or to shortcomings in the models themselves at wavelengths shortward of 1100 ? than at longer wavelengths. Combining this result with that of the Astro-1 HUT calibration (that a synthetic spectrum of G191-B2B and laboratory flux standards gave results consistent within the laboratory measurement uncertainties) demonstrates that pure hydrogen white dwarfs with effective temperatures of 32,000-61,000 K may be used as primary flux standards down to the Galactic Lyman edge. ACS Style Jeffrey W. Kruk; Thomas M. Brown; Arthur F. Davidsen; Brian R. Espey; David S. Finley; Gerard Kriss. Final Astro‐2 Calibration of the Hopkins Ultraviolet Telescope. The Astrophysical Journal Supplement Series 1999 , 122 , 299 -329. AMA Style Jeffrey W. Kruk, Thomas M. Brown, Arthur F. Davidsen, Brian R. Espey, David S. Finley, Gerard Kriss. Final Astro‐2 Calibration of the Hopkins Ultraviolet Telescope. The Astrophysical Journal Supplement Series. 1999; 122 (1):299-329. Chicago/Turabian Style Jeffrey W. Kruk; Thomas M. Brown; Arthur F. Davidsen; Brian R. Espey; David S. Finley; Gerard Kriss. 1999. "Final Astro‐2 Calibration of the Hopkins Ultraviolet Telescope." The Astrophysical Journal Supplement Series 122, no. 1: 299-329. .

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