The Accretion and Obscured Growth of Supermassive Black Holes

The Accretion and Obscured Growth of Supermassive Black Holes
Title The Accretion and Obscured Growth of Supermassive Black Holes PDF eBook
Author Peter Boorman
Publisher Springer Nature
Pages 327
Release 2020-12-02
Genre Science
ISBN 303060361X

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This thesis describes the application of state-of-the-art high-energy X-ray studies to the astronomical quest for understanding obscured active galactic nuclei (AGN). These AGN are supermassive black holes growing by accretion of matter located in the nuclei of galaxies. The material that feeds these black holes also obscures them from view, rendering them challenging to study. It is possible to study them by effectively 'X-raying' galactic nuclei to peer through these obscuring veils. Beginning with the proof-of-concept application of novel X-ray Monte Carlo codes to the Nuclear Spectroscopic Telescope ARray (NuSTAR) spectrum of a known heavily obscured AGN, the thesis establishes the relevant parameters that characterise the AGN spectrum and central black hole growth rate. Next the largest sample of known heavily obscured AGN is compiled, finding the strength of a prominent iron spectral feature to weaken with AGN power. This is puzzling, and suggests that there may be more hidden AGN than previously thought. Finally by combining an all-sky infrared selection with NuSTAR follow-up, new heavily obscured AGN are identified. Obscuration emits infrared radiation, meaning that the infrared-selected AGN catalogue should be representative of the underlying AGN population. The absence of such representative catalogues has continually plagued cosmological studies, and the resultant obscured AGN fraction will be strongly constraining for AGN models.

Pacific Coast of the United States

Pacific Coast of the United States
Title Pacific Coast of the United States PDF eBook
Author United States. Bureau of Light-Houses
Publisher
Pages 692
Release 1928
Genre Beacons
ISBN

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Light List

Light List
Title Light List PDF eBook
Author
Publisher
Pages 892
Release 1947
Genre Aids to navigation
ISBN

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Pacific Coast of the United States. Local Light List Including Lights, Fog Signals, Buoys, and Daymarks, Washington to Alaska, Including British Columbia. Sixteenth and Seventeenth Lighthouse Districts ...

Pacific Coast of the United States. Local Light List Including Lights, Fog Signals, Buoys, and Daymarks, Washington to Alaska, Including British Columbia. Sixteenth and Seventeenth Lighthouse Districts ...
Title Pacific Coast of the United States. Local Light List Including Lights, Fog Signals, Buoys, and Daymarks, Washington to Alaska, Including British Columbia. Sixteenth and Seventeenth Lighthouse Districts ... PDF eBook
Author United States. Bureau of Light-Houses
Publisher
Pages 702
Release 1928
Genre Beacons
ISBN

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Light List, 2013, V. 6, Pacific Coast and Outlying Pacific Islands

Light List, 2013, V. 6, Pacific Coast and Outlying Pacific Islands
Title Light List, 2013, V. 6, Pacific Coast and Outlying Pacific Islands PDF eBook
Author Coast Guard (U.S.)
Publisher Government Printing Office
Pages 316
Release 2013-04-28
Genre Transportation
ISBN 9780160916311

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Contains a list of lights, sound signals, buoys, daybeacons, and other aids to navigation for the United States Pacific Coast and outlying Pacific Islands. The U.S. Coast Guard (USCG) Light List is published in seven volumes and contains lists of lights and other aids to navigation that are maintained by or under the authority of the U.S. Coast Guard and located in the waters surrounding the United States and its Territories. Each volume corresponds to a different regional area and contains more complete information on each aid to navigation than can be conveniently shown on charts. This publication and the data contained within it are maintained and published by the USCG.

Snake Hill

Snake Hill
Title Snake Hill PDF eBook
Author Susan Pfeiffer
Publisher Dundurn
Pages 329
Release 1991-01-30
Genre History
ISBN 1459715802

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In 1987, skeletal remains were encountered during excavation just west of Old Fort Erie, in Ontario’s Niagara Peninsula. While possession of the land had been bitterly contested in 1814, it remained virtually undeveloped and only in the 1980s, with the construction of permanent homes, did excavations yield evidence of the distant past. An international team of scholars and scientists investigated the remains and identified the individuals’ nationalities for repatriation, where appropriate. The resulting archaeological dig has proven crucial to our understanding of the siege of Fort Erie, and provided new information about military clothing, personal gear, medical science, and other details of the day-to-day life of a soldier living under battlefield conditions during the War of 1812. Snake Hill provides a detailed account of this investigation, documenting an important story of suffering and carnage, and providing the reader with a rare glimpse at life and death during the War of 1812. This book contributes significantly to our understanding of events before, during and after Fort Erie’s 1814 siege.

Yosemite Valley--El Portal Comprehensive Design : Project Summary

Yosemite Valley--El Portal Comprehensive Design : Project Summary
Title Yosemite Valley--El Portal Comprehensive Design : Project Summary PDF eBook
Author
Publisher
Pages 124
Release 1987
Genre City planning
ISBN

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