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The Accretion and Obscured Growth of Supermassive Black Holes

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Release : 2020-12-02
Genre : Science
Kind : eBook
Book Rating : 61X/5 ( reviews)

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Book Synopsis The Accretion and Obscured Growth of Supermassive Black Holes by : Peter Boorman

Download or read book The Accretion and Obscured Growth of Supermassive Black Holes written by Peter Boorman. This book was released on 2020-12-02. Available in PDF, EPUB and Kindle. Book excerpt: 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.

An Obscured Quest

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Release : 2024-02-16
Genre : Fiction
Kind : eBook
Book Rating : /5 ( reviews)

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Book Synopsis An Obscured Quest by : Dale Helm

Download or read book An Obscured Quest written by Dale Helm. This book was released on 2024-02-16. Available in PDF, EPUB and Kindle. Book excerpt: About the Book Following two heartbreaking losses, Wayne Chapulis decides to leave the US and take on a business opportunity in Finland, where his mother and brother reside. Soon after his arrival, he receives an old photograph of his dad shaking hands with an unknown man. An Obscured Quest is launched as Wayne tries to determine the man’s identity. During his search, he is brought back to his childhood’s settings and also gets re-introduced to his former best friend’s kid sister, who has grown into a beautiful young woman. Despite that bright spot, Wayne soon finds himself being followed, assaulted in his home, and comes upon the stranger he seeks—murdered. Finnish cops and US Embassy personnel take up an investigation, but the harassment doesn’t stop. Little by little he comes up with new clues to his dad’s decades-old doings that take him on a hunt to Sweden, Holland, and finally back to New England before the secrets his dad left behind are uncovered. About the Author Dale Helm is an ex-military man who, after completion of a university degree, chose a career in international tech business. He has lived in Finland, the Netherlands, and the USA. Currently, Helm lives in the White Mountains of New Hampshire and works remotely as a manager for a high-tech company. He has always been an active sportsman with backgrounds in skiing, soccer, hockey, and most other games you need a racket for. Helm served in the military branch that required extreme outdoors skills, so he is rather proficient in orienteering and surviving in harsh arctic conditions year-round. He has logged nearly a thousand skydive jumps and used to be a jumpmaster. Helm has two grown boys who live on their own and two grandkids. He is married but lives most of the time with his Siberian Husky with whom he hikes and skis on a daily basis. Helm still chases puck weekly, but he guesses these days it can only be called a poor imitation of hockey.

Detection And Identification Of Visually Obscured Targets

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Release : 2019-09-26
Genre : Technology & Engineering
Kind : eBook
Book Rating : 656/5 ( reviews)

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Book Synopsis Detection And Identification Of Visually Obscured Targets by : Carl E. Baum

Download or read book Detection And Identification Of Visually Obscured Targets written by Carl E. Baum. This book was released on 2019-09-26. Available in PDF, EPUB and Kindle. Book excerpt: Beginning with a review of the current need for identification of buried and surface unexplored ordnance such as mines, shells, bombs, this book then explains existing techniques for electromagnetic detection of such targets. A detailed treatment of target signatures (natural frequencies and related parameters) for identification and discrimination of false alarms is also given.

Obscure Diseases of the Brain and Mind

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Release : 1866
Genre : Brain
Kind : eBook
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Book Synopsis Obscure Diseases of the Brain and Mind by : Forbes Winslow

Download or read book Obscure Diseases of the Brain and Mind written by Forbes Winslow. This book was released on 1866. Available in PDF, EPUB and Kindle. Book excerpt:

On the Obscure Diseases of the Brain and Disorders of the Mind

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Release : 1868
Genre : Brain
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Book Synopsis On the Obscure Diseases of the Brain and Disorders of the Mind by : Forbes Winslow

Download or read book On the Obscure Diseases of the Brain and Disorders of the Mind written by Forbes Winslow. This book was released on 1868. Available in PDF, EPUB and Kindle. Book excerpt:

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