Spatially-Resolved Spectra of the "Teacup" AGN: Tracing the History of a Dying Quasar

The Sloan Digital Sky Survey (SDSS) Galaxy Zoo project has revealed a number of spectacular galaxies possessing Extended Emission-Line Regions (EELRs), the most famous being Hanny's Voorwerp galaxy. We present another EELR object discovered in the SDSS endeavor: the Teacup Active Galactic Nucleus (AGN), nicknamed for its EELR, which has a handle like structure protruding 15 kpc into the northeast quadrant of the galaxy. We analyze physical conditions of this galaxy with long-slit ground based spectroscopy from Lowell, Lick, and KPNO observatories. With the Lowell 1.8m Perkin's telescope we took multiple observations at different offset positions, allowing us to recover spatially resolved spectra across the galaxy. Line diagnostics indicate the ionized gas is photoionized primarily by the AGN. Additionally we are able to derive the hydrogen density from the [S II] 6716/6731 ratio. We generated two-component photoionization models for each spatially resolved Lowell spectrum. These models allow us to calculate the AGN bolometric luminosity seen by the gas at different radii from the nuclear center of the Teacup. Our results show a drop in bolometric luminosity by more than two orders of magnitude from the EELR to the nucleus, suggesting that the AGN has decreased in luminosity by this amount in a continuous fashion over 46,000 years, supporting the case for a dying AGN in this galaxy independent of any IR based evidence. We demonstrate that spatially resolved photoionization modeling could be applied to EELRs to investigate long time scale variability.Comment: 38 pages, 11 figures, accepted for publication in the Astrophysical Journa

Swine Trichinella Infection and Geographic Information System Tools

Pastured pigs are vulnerable to Trichinella spiralis infection through exposure to wild reservoir hosts. To evaluate the potential impact of the expanding production of pork from pasture-raised pigs, we mapped locations of T. spiralis occurrence and pastured-pig farms in the United States. Twenty-eight farms were located within 50 km of previous infection

Is the observed high-frequency radio luminosity distribution of QSOs bimodal?

The distribution of QSO radio luminosities has long been debated in the literature. Some argue that it is a bimodal distribution, implying that there are two separate QSO populations (normally referred to as 'radio-loud' and 'radio-quiet'), while others claim it forms a more continuous distribution characteristic of a single population. We use deep observations at 20 GHz to investigate whether the distribution is bimodal at high radio frequencies. Carrying out this study at high radio frequencies has an advantage over previous studies as the radio emission comes predominantly from the core of the AGN, hence probes the most recent activity. Studies carried out at lower frequencies are dominated by the large scale lobes where the emission is built up over longer timescales (10^7-10^8 yrs), thereby confusing the sample. Our sample comprises 874 X-ray selected QSOs that were observed as part of the 6dF Galaxy Survey. Of these, 40% were detected down to a 3 sigma detection limit of 0.2-0.5 mJy. No evidence of bimodality is seen in either the 20 GHz luminosity distribution or in the distribution of the R_20 parameter: the ratio of the radio to optical luminosities traditionally used to classify objects as being either radio-loud or radio-quiet. Previous results have claimed that at low radio luminosities, star formation processes can dominate the radio emission observed in QSOs. We attempt to investigate these claims by stacking the undetected sources at 20 GHz and discuss the limitations in carrying out this analysis. However, if the radio emission was solely due to star formation processes, we calculate that this corresponds to star formation rates ranging from ~10 solar masses/yr to ~2300 solar masses/yr.Comment: 13 pages, 11 figures. Accepted for publication in Ap

Narratives of self and identity in women's prisons: stigma and the struggle for self-definition in penal regimes

A concern with questions of selfhood and identity has been central to penal practices in women's prisons, and to the sociology of women's imprisonment. Studies of women's prisons have remained preoccupied with women prisoners’ social identities, and their apparent tendency to adapt to imprisonment through relationships. This article explores the narratives of women in two English prisons to demonstrate the importance of the self as a site of meaning for prisoners and the central place of identity in micro-level power negotiations in prisons

Reverberation Mapping Results for Five Seyfert 1 Galaxies

We present the results from a detailed analysis of photometric and spectrophotometric data on five Seyfert 1 galaxies observed as a part of a recent reverberation mapping program. The data were collected at several observatories over a 140-day span beginning in 2010 August and ending in 2011 January. We obtained high sampling-rate light curves for Mrk 335, Mrk 1501, 3C120, Mrk 6, and PG2130+099, from which we have measured the time lag between variations in the 5100 Angstrom continuum and the H-beta broad emission line. We then used these measurements to calculate the mass of the supermassive black hole at the center of each of these galaxies. Our new measurements substantially improve previous measurements of MBH and the size of the broad line-emitting region for four sources and add a measurement for one new object. Our new measurements are consistent with photoionization physics regulating the location of the broad line region in active galactic nuclei.Comment: 45 pages, 5 figures. Accepted for publication in ApJ. For a brief video explaining the key results of this paper, see http://www.youtube.com/user/OSUAstronom

Reverberation Mapping of the Seyfert 1 Galaxy NGC 7469

A large reverberation mapping study of the Seyfert 1 galaxy NGC 7469 has yielded emission-line lags for Hbeta 4861 and He II 4686 and a central black hole mass measurement of about 10 million solar masses, consistent with previous measurements. A very low level of variability during the monitoring campaign precluded meeting our original goal of recovering velocity-delay maps from the data, but with the new Hbeta measurement, NGC 7469 is no longer an outlier in the relationship between the size of the Hbeta-emitting broad-line region and the AGN luminosity. It was necessary to detrend the continuum and Hbeta and He II 4686 line light curves and those from archival UV data for different time-series analysis methods to yield consistent results.Comment: 9 Pages, 7 figures, 6 tables. Accepted for publication in The Astrophysical Journa

Global reorganization of deep-sea circulation and carbon storage after the last ice age

Funding information: This work was supported by grants from the National Science Foundation (OCE-2015647 and OCE-2032340 to PAR; OCE- 2032343 to MPH); NERC grant NE/N011716/1 to JWBR and NERC grant NE/M004619/1 to AB.Using new and published marine fossil radiocarbon (14C/C) measurements, a tracer uniquely sensitive to circulation and air-sea gas exchange, we establish several benchmarks for Atlantic, Southern, and Pacific deep-sea circulation and ventilation since the last ice age. We find the most 14C-depleted water in glacial Pacific bottom depths, rather than the mid-depths as they are today, which is best explained by a slowdown in glacial deep-sea overturning in addition to a “flipped” glacial Pacific overturning configuration. These observations cannot be produced by changes in air-sea gas exchange alone, and they underscore the major role for changes in the overturning circulation for glacial deep-sea carbon storage in the vast Pacific abyss and the concomitant drawdown of atmospheric CO2.Publisher PDFPeer reviewe

Assessment of C, N and Si isotopes as tracers of past ocean nutrient and carbon cycling

Biological productivity in the ocean directly influences the partitioning of carbon between the atmosphere and ocean interior. Through this carbon cycle feedback, changing ocean productivity has long been hypothesized as a key pathway for modulating past atmospheric carbon dioxide levels and hence global climate. Because phytoplankton preferentially assimilate the light isotopes of carbon and the major nutrients nitrate and silicic acid, stable isotopes of carbon (C), nitrogen (N), and silicon (Si) in seawater and marine sediments can inform on ocean carbon and nutrient cycling, and by extension the relationship with biological productivity and global climate. Here, we compile water column C, N, and Si stable isotopes from GEOTRACES-era data in four key ocean regions to review geochemical proxies of oceanic carbon and nutrient cycling based on the C, N, and Si isotopic composition of marine sediments. External sources and sinks as well as internal cycling (including assimilation, particulate matter export, and regeneration) are discussed as likely drivers of observed C, N, and Si isotope distributions in the ocean. The potential for C, N, and Si isotope measurements in sedimentary archives to record aspects of past ocean C and nutrient cycling is evaluated, along with key uncertainties and limitations associated with each proxy. Constraints on ocean C and nutrient cycling during late Quaternary glacial-interglacial cycles and over the Cenozoic are examined. This review highlights opportunities for future research using multielement stable isotope proxy applications and emphasizes the importance of such applications to reconstructing past changes in the oceans and climate system

Assessment of C, N, and Si Isotopes as Tracers of Past Ocean Nutrient and Carbon Cycling

28 pages, 6 figures, 1 box, 1 appendix.-- Data Availability Statement: Data sets presented in this research are available via the following repositories and study (listed by Figure): Figures 3 and 4: (1)δ13CDIC:(a) CLIVAR P16S (Feely et al., 2008) from GLODAPv2.2020 database (Olsen et al., 2020): https://www.glodap.info/index.php/merged-and-adjusted-data-product/. (b) GEOTRACES GA03 (Quay & Wu, 2015) and GP16 (P. Quay, unpublished data) from GEOTRACES IDP2017 (Schlitzer et al., 2018): https://www.bodc.ac.uk/geotraces/data/idp2017/. (2) δ15Nnitrate:(a) CLIVAR P16S (Rafter et al., 2013) from BCO-DMO: https://www.bco-dmo.org/dataset/651722. (b) GEOTRACES GA03 (Marconi et al., 2015) and GP16 (Peters et al., 2018) from GEOTRACES IDP2017 (Schlitzer et al., 2018): https://www.bodc.ac.uk/geotraces/data/idp2017/. (3) δ30Si: GEOTRACES GA03 (Brzezinski & Jones, 2015) and GIPY04 (Fripiat et al., 2012) from GEOTRACES IDP2017 (Schlitzer et al., 2018): https://www.bodc.ac.uk/geotraces/data/idp2017/. (4) Figure 4a POC Flux (DeVries & Weber, 2017): SIMPLE-TRIM Output from https://tdevries.eri.ucsb.edu/models-and-data-products/. Figure 5: (a) Antarctic CO2 composite: https://www.ncdc.noaa.gov/paleo-search/study/17975. (b) ∆δ13Cthermocline-deep from Ziegler et al. (2013) supporting information: https://www.nature.com/articles/ngeo1782; ∆δ13Cepifaunal-infaunal (Hoogakker et al., 2018): https://doi.pangaea.de/10.1594/PANGAEA.891185. (c) SAZ FB-δ15N (Martínez-García et al., 2014): https://www.ncdc.noaa.gov/paleo/study/18318; AZ DB-δ15N (Studer et al., 2015): https://doi.pangaea.de/10.1594/PANGAEA.848271. (d) SAZ Fe flux (Martínez-García et al., 2014): https://www.ncdc.noaa.gov/paleo/study/18318. (e) AZ diatom δ30Si (Robinson et al., 2014): https:// www.ncdc.noaa.gov/paleo/study/17917. Figure 6: (a) and (b) Benthic foraminifera δ18O and δ13C (Zachos et al., 2001): https:// www.ncdc.noaa.gov/paleo/study/8674. (c) FB-δ15N from Kast et al. (2019) supporting information data: https://science.sciencemag.org/content/suppl/2019/04/24/364.6438.386.DC1. (d) and (e) Diatom, sponge, and radiolarian δ30Si in Egan et al. (2013) supporting information: https://www.sciencedirect.com/science/article/pii/S0012821X13002185, Fontorbe et al. (2016) supporting information: https://www.sciencedirect.com/science/article/pii/S0012821X16304265, and Fontorbe et al. (2017) supporting information: https://agupubs.onlinelibrary.wiley.com/doi/full/10.1002/2017PA003090Biological productivity in the ocean directly influences the partitioning of carbon between the atmosphere and ocean interior. Through this carbon cycle feedback, changing ocean productivity has long been hypothesized as a key pathway for modulating past atmospheric carbon dioxide levels and hence global climate. Because phytoplankton preferentially assimilate the light isotopes of carbon and the major nutrients nitrate and silicic acid, stable isotopes of carbon (C), nitrogen (N), and silicon (Si) in seawater and marine sediments can inform on ocean carbon and nutrient cycling, and by extension the relationship with biological productivity and global climate. Here, we compile water column C, N, and Si stable isotopes from GEOTRACES-era data in four key ocean regions to review geochemical proxies of oceanic carbon and nutrient cycling based on the C, N, and Si isotopic composition of marine sediments. External sources and sinks as well as internal cycling (including assimilation, particulate matter export, and regeneration) are discussed as likely drivers of observed C, N, and Si isotope distributions in the ocean. The potential for C, N, and Si isotope measurements in sedimentary archives to record aspects of past ocean C and nutrient cycling is evaluated, along with key uncertainties and limitations associated with each proxy. Constraints on ocean C and nutrient cycling during late Quaternary glacial-interglacial cycles and over the Cenozoic are examined. This review highlights opportunities for future research using multielement stable isotope proxy applications and emphasizes the importance of such applications to reconstructing past changes in the oceans and climate systemThis workshop was funded by the United States National Science Foundation (NSF) through the GEOTRACES program, the international Past Global Changes (PAGES) project, which in turn received support from the Swiss Academy of Sciences and NSF, and the French national program LEFE (Les Enveloppes Fluides et l'Environnement). [...] This study was supported by PAGES, LEFE, and GEOTRACES through NSF. J. R. Farmer acknowledges support from the Max Planck Society, the Tuttle Fund of the Department of Geosciences of Princeton University, the Grand Challenges Program of the Princeton Environmental Institute, and through Exxon Mobil via the Andlinger Center for Energy and the Environment of Princeton University. Open access funding enabled and organized by Projekt DEAL. [...] With the institutional support of the ‘Severo Ochoa Centre of Excellence’ accreditation (CEX2019-000928-S

Joint H-alpha and X-Ray Observations of Massive X-Ray Binaries. II. The Be X-ray Binary and Microquasar LS I +61 303

We present the results of an H-alpha monitoring campaign on the BeXRB and microquasar system LS I +61 303. We use radial velocity measurements of HeI lines in our spectra to re-evaluate the orbital elements and to better establish the time of periastron. We list equivalent widths and other parameters for the H-alpha emission line and discuss the orbital phase related variations observed. We call attention to a dramatic episode of emission weakening that occurred in less than a day that probably resulted from exposure to a transient source of ionizing radiation. We argue that the increase in H-alpha and X-ray emission following periastron probably results from the creation of an extended density wave in the disk created by tidal forces. We also discuss estimates of the size of the disk from the H-alpha equivalent width measurements, and we suggest that the disk radius from the average equivalent width corresponds to a resonant truncation radius of the disk while the maximum equivalent width corresponds to a radius limited by the separation of the stars at periastron. We note that a nearby faint companion is probably an unrelated foreground object.Comment: 18 pages including 7 figures and 2 tables, accepted to Ap