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25 results on '"Powell, M.C."'

2. The Close AGN Reference Survey (CARS): No evidence of galaxy-scale hot outflows in two nearby AGN

Author

European Commission, Ministerio de Economía y Competitividad (España), National Aeronautics and Space Administration (US), German Research Foundation, Science and Technology Facilities Council (UK), Powell, M.C., Husemann, B., Tremblay, G.R., Krumpe, M., Urrutia, T., Baum, S.A., Busch, G., Combes, F., Croom, S.M., Davis, T.A., Eckart, A., O'Dea, C.P., Pérez-Torres, Miguel A., Scharwächter, J., Smirnova-Pinchukova, I., Urry, C.M., European Commission, Ministerio de Economía y Competitividad (España), National Aeronautics and Space Administration (US), German Research Foundation, Science and Technology Facilities Council (UK), Powell, M.C., Husemann, B., Tremblay, G.R., Krumpe, M., Urrutia, T., Baum, S.A., Busch, G., Combes, F., Croom, S.M., Davis, T.A., Eckart, A., O'Dea, C.P., Pérez-Torres, Miguel A., Scharwächter, J., Smirnova-Pinchukova, I., and Urry, C.M.

Abstract

Aims. We probe the radiatively-efficient, hot wind feedback mode in two nearby luminous unobscured (type 1) AGN from the Close AGN Reference Survey (CARS), which show intriguing kpc-scale arc-like features of extended [O III]ionized gas as mapped with VLT-MUSE. We aimed to detect hot gas bubbles that would indicate the existence of powerful, galaxy-scale outflows in our targets, HE 0227-0931 and HE 0351+0240, from deep (200 ks) Chandra observations. Methods. By measuring the spatial and spectral properties of the extended X-ray emission and comparing with the sub kpc-scale IFU data, we are able to constrain feedback scenarios and directly test if the ionized gas is due to a shocked wind. Results. No extended hot gas emission on kpc-scales was detected. Unless the ambient medium density is low (n ∼ 1 cm at 100 pc), the inferred upper limits on the extended X-ray luminosities are well below what is expected from theoretical models at matching AGN luminosities. Conclusions. We conclude that the highly-ionized gas structures on kpc scales are not inflated by a hot outflow in either target, and instead are likely caused by photoionization of pre-existing gas streams of different origins. Our nondetections suggest that extended X-ray emission from an AGN-driven wind is not universal, and may lead to conflicts with current theoretical predictions.© ESO 2018

Published
2018

22. Rupture of a tubal pregnancy following successful treatment with methotrexate

Author

Cane, P., Wijngaarden, W., and Powell, M.C.

Abstract

We report a case of a woman not wanting surgery for an ectopic pregnancy, whose HCG titres successfully fell to an undetectable level whereupon the ectopic ruptured. This case illustrates the need for a careful prolonged follow-up with serial HCG measurements when methotrexate is employed for the treatment of ectopic pregnancy.

Published
1997
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24. BAT AGN Spectroscopic Survey XXVII: Scattered X-Ray radiation in obscured active galactic nuclei

Author

Fiona A. Harrison, Enrico Piconcelli, Sylvain Veilleux, Luca Zappacosta, Richard F. Mushotzky, A. Tortosa, Federica Ricci, Ahmed Elagali, Benny Trakhtenbrot, D. Kakkad, Claudio Ricci, K. K. Gupta, Kyuseok Oh, T. Kawamuro, Michael Koss, C. M. Urry, Turgay Caglar, M. C. Powell, Yoshihiro Ueda, Franz E. Bauer, Kohei Ichikawa, D. Stern, George C. Privon, Gupta, K.K., Ricci, C., Tortosa, A., Ueda, Y., Kawamuro, T., Koss, M., Trakhtenbrot, B., Oh, K., Bauer, F.E., Ricci, F., Privon, G.C., Zappacosta, L., Stern, D., Kakkad, D., Piconcelli, E., Veilleux, S., Mushotzky, R., Caglar, T., Ichikawa, K., Elagali, A., Powell, M.C., Urry, C.M., Harrison, F., K Gupta, K, Ricci, C, Tortosa, A, Ueda, Y, Kawamuro, T, Koss, M, Trakhtenbrot, B, Oh, K, E Bauer, F, Ricci, F, C Privon, G, Zappacosta, L, Stern, D, Kakkad, D, Piconcelli, E, Veilleux, S, Mushotzky, R, Caglar, T, Ichikawa, K, Elagali, A, C Powell, M, M Urry, C, and Harrison, F

Subjects
Galaxies: Seyfert, Active galactic nucleus, Astrophysics - astrophysics of galaxies, Astrophysics::High Energy Astrophysical Phenomena, FOS: Physical sciences, Quasars: supermassive black holes, Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, X-rays: general, Astrophysics - high energy astrophysical phenomena, 01 natural sciences, Spectral line, Luminosity, Seyfert [galaxies], Primary (astronomy), general [X-rays], 0103 physical sciences, galaxies: active – X-rays: general – galaxies: Seyfert – quasars: general – quasars: supermassive black holes, 010303 astronomy & astrophysics, Astrophysics::Galaxy Astrophysics, High Energy Astrophysical Phenomena (astro-ph.HE), Physics, Supermassive black hole, general [quasars], 010308 nuclear & particles physics, Scattering, supermassive black holes [quasars], Astronomy and Astrophysics, Torus, Galaxies: active, Quasars: general, Black hole, Space and Planetary Science, Astrophysics of Galaxies (astro-ph.GA), active [galaxies]
Abstract

Accreting supermassive black holes (SMBHs), also known as active galactic nuclei (AGN), are generally surrounded by large amounts of gas and dust. This surrounding material reprocesses the primary X-ray emission produced close to the SMBH and gives rise to several components in the broadband X-ray spectra of AGN, including a power-law possibly associated with Thomson-scattered radiation. In this work, we study the properties of this scattered component for a sample of 386 hard-X-ray-selected, nearby ($z \sim 0.03$) obscured AGN from the 70-month Swift/BAT catalog. We investigate how the fraction of Thomson-scattered radiation correlates with different physical properties of AGN, such as line-of-sight column density, X-ray luminosity, black hole mass, and Eddington ratio. We find a significant negative correlation between the scattering fraction and the column density. Based on a large number of spectral simulations, we exclude the possibility that this anti-correlation is due to degeneracies between the parameters. The negative correlation also persists when considering different ranges of luminosity, black hole mass, and Eddington ratio. We discuss how this correlation might be either due to the angle dependence of the Thomson cross-section or to more obscured sources having a higher covering factor of the torus. We also find a positive correlation between the scattering fraction and the ratio of [OIII] $\lambda$5007 to X-ray luminosity. This result is consistent with previous studies and suggests that the Thomson-scattered component is associated with the narrow-line region., Comment: Accepted for publication in MNRAS, 18 pages, 9 figures, 2 tables, 1 equation

Published
2021

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