Far-Ultraviolet Observations of NGC 3516 using the Hopkins Ultraviolet Telescope

We observed the Seyfert 1 galaxy NGC 3516 twice during the flight of Astro-2 using the Hopkins Ultraviolet Telescope in March 1995. Simultaneous X-ray observations were performed with ASCA. Our far-ultraviolet spectra cover the spectral range 820-1840 A with a resolution of 2-4 A. No significant variations were found between the two observations. The total spectrum shows a red continuum, $f_\nu \sim \nu^{-1.89}$, with an observed flux of $\rm 2.2 \times 10^{-14}~erg~cm^{-2}~s^{-1}~\AA^{-1}$ at 1450 A, slightly above the historical mean. Intrinsic absorption in Lyman $\beta$ is visible as well as absorption from O~vi 1032,1038, N~v 1239,1243, Si~iv 1394,1403, and C~iv 1548,1551. The UV absorption lines are far weaker than is usual for NGC~3516, and also lie closer to the emission line redshift rather than showing the blueshift typical of these lines when they are strong. The neutral hydrogen absorption, however, is blueshifted by $400~\rm km~s^{-1}$ relative to the systemic velocity, and it is opaque at the Lyman limit. The sharpness of the cutoff indicates a low effective Doppler parameter, $b < \rm 20~km~s^{-1}$. For $b = \rm 10~km~s^{-1}$ the derived intrinsic column is $\rm 3.5 \times 10^{17}~cm^{-2}$. As in NGC~4151, a single warm absorber cannot produce the strong absorption visible over the wide range of observed ionization states. Matching both the UV and X-ray absorption simultaneously requires absorbers spanning a range of $10^3$ in both ionization parameter and column density.Comment: 18 pages, 4 PostScript figures, uses aaspp4.sty To appear in the August 20, 1996, issue of The Astrophysical Journa

Far-UV Observations of NGC 4151 during the ORFEUS-SPAS II Mission

We observed the Seyfert 1 galaxy NGC 4151 on eleven occasions at 1-2 day intervals using the Berkeley spectrometer during the ORFEUS-SPAS II mission in 1996 November. The mean spectrum covers 912-1220 A at ~0.3 A resolution with a total exposure of 15,658 seconds. The mean flux at 1000 A was 4.7e-13 erg/cm^2/s/A. We identify the neutral hydrogen absorption with a number of components that correspond to the velocity distribution of \ion{H}{1} seen in our own Galaxy as well as features identified in the CIV 1549 absorption profile by Weymann et al. The main component of neutral hydrogen in NGC 4151 has a total column density of log N_HI = 18.7 +/- 1.5 cm^{-2} for a Doppler parameter b=250 +/- 50 km/s, and it covers 84 +/- 6% of the source. This is consistent with previous results obtained with the Hopkins Ultraviolet Telescope. Other intrinsic far-UV absorption features are not resolved, but the CIII* 1176 absorption line has a significantly higher blueshift relative to NGC 4151 than the CIII 977 resonance line. This implies that the highest velocity region of the outflowing gas has the highest density. Variations in the equivalent width of the CIII* 1176 absorption line anticorrelate with continuum variations on timescales of days. For an ionization timescale <1 day, we set an upper limit of 25 pc on the distance of the absorbing gas from the central source. The OVI 1034 and HeII 1085 emission lines also vary on timescales of 1-2 days, but their response to the continuum variations is complex. For some continuum variations they show no response, while for others the response is instantaneous to the limit of our sampling interval.Comment: 4 pages, 2 PostScript figures, uses emulateapj.sty, apjfonts.sty. To appear in the Astrophysical Journal (Letters) special issue for ORFEU

Fe VII lines in the spectrum of RR Telescopii

Thirteen transitions within the ground 3d^2 configuration of Fe VII are identified in ultraviolet and optical spectra of the symbiotic star RR Telescopii obtained with the STIS instrument of the Hubble Space Telescope. The line fluxes are compared with theoretical data computed with the recent atomic data of K.A. Berrington et al., and high resolution optical spectra from VLT/UVES are used to identify blends. Seven branching ratios are measured, with three in good agreement with theory and one affected by blending. The lambda5277/lambda4943 branching ratio is discrepant by > 3 sigma, indicating errors in the atomic data for the lambda5277 line. A least-squares minimization scheme is used to simultaneously derive the temperature, T, and density, N_e, of the RR Tel nebula, and the interstellar extinction, E(B-V), towards RR Tel from the complete set of emission lines. The derived values are: log T/K = 4.50 +/- 0.23, log N_e/cm^-3=7.25 +/- 0.05, and E(B-V)<0.27. The extinction is not well-constrained by the Fe VII lines, but is consistent with the more accurate value E(B-V)=0.109^{+0.052}_{-0.059} derived here from the Ne V lambda2974/lambda1574 ratio in the STIS spectrum. Large differences between the K.A. Berrington et al. electron excitation data and the earlier F.P. Keenan & P.H. Norrington data-set are demonstrated, and the latter is shown to give worse agreement with observations.Comment: To be published in Astronomy & Astrophysics; 7 pages, 4 figure

ASCA Observations of the Composite Warm Absorber in NGC 3516

We obtained X-ray spectra of the Seyfert 1 galaxy NGC~3516 in March 1995 using ASCA. Simultaneous far-UV observations were obtained with HUT on the Astro-2 shuttle mission. The ASCA spectrum shows a lightly absorbed power law of energy index 0.78. The low energy absorbing column is significantly less than previously seen. Prominent O~vii and O~viii absorption edges are visible, but, consistent with the much lower total absorbing column, no Fe K absorption edge is detectable. A weak, narrow Fe~K$\alpha$ emission line from cold material is present as well as a broad Fe~K$\alpha$ line. These features are similar to those reported in other Seyfert 1 galaxies. A single warm absorber model provides only an imperfect description of the low energy absorption. In addition to a highly ionized absorber with ionization parameter $U = 1.66$ and a total column density of $1.4 \times 10^{22}~\rm cm^{-2}$, adding a lower ionization absorber with $U = 0.32$ and a total column of $6.9 \times 10^{21}~\rm cm^{-2}$ significantly improves the fit. The contribution of resonant line scattering to our warm absorber models limits the Doppler parameter to $< 160~\rm km~s^{-1}$ at 90\% confidence. Turbulence at the sound speed of the photoionized gas provides the best fit. None of the warm absorber models fit to the X-ray spectrum can match the observed equivalent widths of all the UV absorption lines. Accounting for the X-ray and UV absorption simultaneously requires an absorbing region with a broad range of ionization parameters and column densities.Comment: 14 pages, 4 Postscript figures, uses aaspp4.sty To appear in the August 20, 1996, issue of The Astrophysical Journa

The role of combining national official statistics with global monitoring to close the data gaps in the environmental SDGs

The Sustainable Development Goals (SDGs) have elevated the profile of the environmental dimension of development – and how we monitor this dimension. However, they have also challenged national statistical systems and the global statistical community to put in place both the methodologies and mechanisms for data collection and reporting on environmental indicators. According to a recent analysis, there is too little data to formally assess the status of 68% of the environment-related SDGs [1]. Many environment-related indicators were not part of the purview of national statistical systems and did not have a methodology or data collection system in place prior to the adoption of the SDG indicator framework [2]. Moderate improvements have been made, as evidenced by the reduced proportion of environment-related SDG indicators classified as Tier III between the original classification in 2016 and May 2019 – dropping from 50% to 28% [3]. As of March 2020, there are currently no Tier III indicators; however, as many of the SDG indicators have been recently reclassified the data availability and experience in compiling these indicators is severely limited. Socioeconomic indicators have far outpaced environmental indicators in this shift, with only 7% of non-environmental indicators classified as Tier III in May 2019 [1,4,5]. As the custodian agency for 26 of the environment-related SDG indicators, UN Environment is establishing methodologies and mechanisms to collect country-level data. However, many countries currently do not have national systems in place for monitoring these environmental indicators and thus there is a risk that much of the environmental dimension of development cannot be captured by using reporting mechanisms which only include traditionally collected national official statistics. For many of these indicators, UN Environment is exploring new data sources, such as data from citizen science. Citizen science has the potential to contribute to global and local level SDG monitoring. Realizing its full potential however, would require building key partnerships around citizen science data and creating an enabling environment. Global modelling is another approach to fill data gaps. These new types of data could not only improve global estimations but could be incorporated in national official statistics in order to improve nationally relevant data and analysis [6]. The Global Material Flow database, which estimates Domestic Material Consumption (covering SDG indicators 8.4.2 and 12.2.2), and the Global Surface Water Explorer application (covering SDG indicator 6.6.1) are a couple of examples of where UN Environment is complementing national data with global data products in the official SDG reporting process. In these cases the use of globally-derived data has been agreed by the Inter-Agency and Expert Group on SDG Indicators (IAEG-SDGs) [7]. Expanding globally-estimated or -modelled data to cover environment-related SDG indicators could build the foundation for a digital ecosystem for the planet, which would provide a basis for developing integrated analysis and insights. A Sustainability Gap Index could be one mechanism to bring together the environmental dimension of development into a single metric, which could inform the achievement of the SDGs, environmental assessments and national policy. This paper presents a summary of how the world is faring in terms of measuring the environmental dimension of the SDGs

Methods for Improving Cancer Surveillance Data in American Indian and Alaska Native Populations

BACKGROUND. The misclassification of race decreases the accuracy of cancer incidence data for American Indians and Alaska Natives (AI/ANs) in some central cancer registries. This article describes the data sources and methods that were used to address this misclassification and to produce the cancer statistics used by most of the articles in this supplement. METHODS. Records from United States cancer registries were linked with Indian Health Service (IHS) records to identify AI/AN cases that were misclassified as non-AI/AN. Data were available from 47 registries that linked their data with IHS, met quality criteria, and agreed to participate. Analyses focused on cases among AI/AN residents in IHS Contract Health Service Delivery Area (CHSDA) counties in 33 states. Cancer incidence and stage data were compiled for non-Hispanic whites (NHWs) and AI/ANs across 6 IHS regions of the United States for 1999 through 2004. RESULTS. Misclassification of AI/AN race as nonnative in central cancer registries ranged from 85 individuals in Alaska (3.4%) to 5297 individuals in the Southern Plains (44.5%). Cancer incidence rates among AI/ANs for all cancers combined were lower than for NHWs, but incidence rates varied by geographic region for AI/ANs. Restricting the rate calculations to CHSDA counties generally resulted in higher rates than those obtained for all counties combined. CONCLUSIONS. The classification of race for AI/AN cases in cancer registries can be improved by linking records to the IHS and stratifying by CHSDA counties. Cancer in the AI/AN population is clarified further by describing incidence rates by geographic region. Improved cancer surveillance data for AI/AN communities should aid in the planning, implementation, and evaluation of more effective cancer control and should reduce health disparities in this population

Intergalactic UV Background Radiation Field

We have performed proximity effect analysis of low and high resolution data, considering detailed frequency and redshift dependence of the AGN spectra processed through galactic and intergalactic material. We show that such a background flux, calculated using the observed distribution of AGNs, falls short of the value required by the proximity effect analysis by a factor of $\ge$ 2.7. We have studied the uncertainty in the value of the required flux due to its dependence on the resolution, description of column density distribution, systemic redshifts of QSOs etc. We conclude that in view of these uncertainties the proximity effect is consistent with the background contributed by the observed AGNs and that the hypothesized presence of an additional, dust extinct, population of AGNs may not be necessary.Comment: To be published in the Journal of Astronomy and Astrophysics aasms, 2 figures, 2 tables. Paper replaced to include the figure