Gamma-rays from AGN in dwarf galaxies
Autor(a) principal: | |
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Data de Publicação: | 2023 |
Tipo de documento: | Dissertação |
Idioma: | eng |
Título da fonte: | Biblioteca Digital de Teses e Dissertações da USP |
Texto Completo: | https://www.teses.usp.br/teses/disponiveis/14/14131/tde-01032023-094456/ |
Resumo: | Understanding the physics and demographics of black holes (BHs) in the intermediate-mass regime can lead us to a better understanding of the processes of AGN feedback, BH-galaxy co-evolution, and even shed light on the mechanisms that formed the seeds of todays supermassive black holes. A promising approach to learn about the activity of the elusive intermediate-mass BHs is to look for their high energy emission in nearby dwarf galaxies. In this work we have used 13 years of data from the Large Area Telescope (LAT) aboard the Fermi spacecraft and implemented a stacking analysis to look for possible -rays from a 135 dwarf galaxies exhibiting signatures of AGN activity in different parts of the electromagnetic spectrum. With our stacking technique, we find that dwarf AGN as a population are significant -ray emitters even though most objects are individually too faint. Two target galaxies constitute strong candidates for -ray sources, both represent 4 excesses and have luminosities of up to 10^ erg/s. We explore possible correlations involving the luminosities of our dwarf AGN population and find the two strongest candidates are too bright when compared to the -ray activity expected from their host galaxys star formation rates, suggesting the AGN contribution to this band is surpassing that of typical stellar processes. The large values of for the best candidates also raises the possibility that their emission has its origin in hitherto undetected relativistic jets. |
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Gamma-rays from AGN in dwarf galaxiesRaios gama de AGN em galáxias anãsAGNAGNblack holesburacos negrosdwarf galaxiesGaláxias anãsgamma-raysraios gamaUnderstanding the physics and demographics of black holes (BHs) in the intermediate-mass regime can lead us to a better understanding of the processes of AGN feedback, BH-galaxy co-evolution, and even shed light on the mechanisms that formed the seeds of todays supermassive black holes. A promising approach to learn about the activity of the elusive intermediate-mass BHs is to look for their high energy emission in nearby dwarf galaxies. In this work we have used 13 years of data from the Large Area Telescope (LAT) aboard the Fermi spacecraft and implemented a stacking analysis to look for possible -rays from a 135 dwarf galaxies exhibiting signatures of AGN activity in different parts of the electromagnetic spectrum. With our stacking technique, we find that dwarf AGN as a population are significant -ray emitters even though most objects are individually too faint. Two target galaxies constitute strong candidates for -ray sources, both represent 4 excesses and have luminosities of up to 10^ erg/s. We explore possible correlations involving the luminosities of our dwarf AGN population and find the two strongest candidates are too bright when compared to the -ray activity expected from their host galaxys star formation rates, suggesting the AGN contribution to this band is surpassing that of typical stellar processes. The large values of for the best candidates also raises the possibility that their emission has its origin in hitherto undetected relativistic jets.Entender a física e demografias dos buracos negros (BHs) no regime de massa intermediária pode nos levar a um melhor entendimento dos processos de feedback de AGN, co-evolução galaxia-BH, e até iluminar os mecanismos que formaram as sementes dos buracos negros supermassivos de hoje em dia. Uma abordagem promissora para aprender sobre a atividade dos BHs de massa intermediária é a busca por sua emissão de fótons de altas energias em galáxias anãs locais. Neste trabalho, utilizamos 13 anos de dados do Large Area Telescope (LAT) a bordo da espaçonave Fermi e implementamos uma técnica de stacking para procurar pelos raios- de uma população de 135 galáxias anãs que exibem assinaturas de AGN em diferentes partes do espectro eletromagnético. Com nosso método de stacking, encontramos emissão significativa vinda desta população, mesmo que a maioria dos objetos sejam fracos demais para serem detectados individualmente. Duas das galáxias alvo são fortes candidatos a fontes de raios-, exibindo excessos de 4 cada um e luminosidades da ordem de L 10^42 erg/s. Nós exploramos possíveis correlações envolvendo as luminosidades de nossa população de AGN em anãs, e encontramos que os candidatos mais fortes exibem luminosidades em raios- acima do esperado a partir das taxas de formação estelar observadas de suas galáxias, o que sugere que a contribuição do AGN para esta banda está superando a de processos estelares típicos. Os altos valores de L para os melhores candidatos levanta a possibilidade de que sua emissão origina em jatos relativísticos até então não detectados.Biblioteca Digitais de Teses e Dissertações da USPSilva, Rodrigo Nemmen daCarlos, Douglas Ferreira2023-01-20info:eu-repo/semantics/publishedVersioninfo:eu-repo/semantics/masterThesisapplication/pdfhttps://www.teses.usp.br/teses/disponiveis/14/14131/tde-01032023-094456/reponame:Biblioteca Digital de Teses e Dissertações da USPinstname:Universidade de São Paulo (USP)instacron:USPLiberar o conteúdo para acesso público.info:eu-repo/semantics/openAccesseng2023-03-02T16:58:46Zoai:teses.usp.br:tde-01032023-094456Biblioteca Digital de Teses e Dissertaçõeshttp://www.teses.usp.br/PUBhttp://www.teses.usp.br/cgi-bin/mtd2br.plvirginia@if.usp.br|| atendimento@aguia.usp.br||virginia@if.usp.bropendoar:27212023-03-02T16:58:46Biblioteca Digital de Teses e Dissertações da USP - Universidade de São Paulo (USP)false |
dc.title.none.fl_str_mv |
Gamma-rays from AGN in dwarf galaxies Raios gama de AGN em galáxias anãs |
title |
Gamma-rays from AGN in dwarf galaxies |
spellingShingle |
Gamma-rays from AGN in dwarf galaxies Carlos, Douglas Ferreira AGN AGN black holes buracos negros dwarf galaxies Galáxias anãs gamma-rays raios gama |
title_short |
Gamma-rays from AGN in dwarf galaxies |
title_full |
Gamma-rays from AGN in dwarf galaxies |
title_fullStr |
Gamma-rays from AGN in dwarf galaxies |
title_full_unstemmed |
Gamma-rays from AGN in dwarf galaxies |
title_sort |
Gamma-rays from AGN in dwarf galaxies |
author |
Carlos, Douglas Ferreira |
author_facet |
Carlos, Douglas Ferreira |
author_role |
author |
dc.contributor.none.fl_str_mv |
Silva, Rodrigo Nemmen da |
dc.contributor.author.fl_str_mv |
Carlos, Douglas Ferreira |
dc.subject.por.fl_str_mv |
AGN AGN black holes buracos negros dwarf galaxies Galáxias anãs gamma-rays raios gama |
topic |
AGN AGN black holes buracos negros dwarf galaxies Galáxias anãs gamma-rays raios gama |
description |
Understanding the physics and demographics of black holes (BHs) in the intermediate-mass regime can lead us to a better understanding of the processes of AGN feedback, BH-galaxy co-evolution, and even shed light on the mechanisms that formed the seeds of todays supermassive black holes. A promising approach to learn about the activity of the elusive intermediate-mass BHs is to look for their high energy emission in nearby dwarf galaxies. In this work we have used 13 years of data from the Large Area Telescope (LAT) aboard the Fermi spacecraft and implemented a stacking analysis to look for possible -rays from a 135 dwarf galaxies exhibiting signatures of AGN activity in different parts of the electromagnetic spectrum. With our stacking technique, we find that dwarf AGN as a population are significant -ray emitters even though most objects are individually too faint. Two target galaxies constitute strong candidates for -ray sources, both represent 4 excesses and have luminosities of up to 10^ erg/s. We explore possible correlations involving the luminosities of our dwarf AGN population and find the two strongest candidates are too bright when compared to the -ray activity expected from their host galaxys star formation rates, suggesting the AGN contribution to this band is surpassing that of typical stellar processes. The large values of for the best candidates also raises the possibility that their emission has its origin in hitherto undetected relativistic jets. |
publishDate |
2023 |
dc.date.none.fl_str_mv |
2023-01-20 |
dc.type.status.fl_str_mv |
info:eu-repo/semantics/publishedVersion |
dc.type.driver.fl_str_mv |
info:eu-repo/semantics/masterThesis |
format |
masterThesis |
status_str |
publishedVersion |
dc.identifier.uri.fl_str_mv |
https://www.teses.usp.br/teses/disponiveis/14/14131/tde-01032023-094456/ |
url |
https://www.teses.usp.br/teses/disponiveis/14/14131/tde-01032023-094456/ |
dc.language.iso.fl_str_mv |
eng |
language |
eng |
dc.relation.none.fl_str_mv |
|
dc.rights.driver.fl_str_mv |
Liberar o conteúdo para acesso público. info:eu-repo/semantics/openAccess |
rights_invalid_str_mv |
Liberar o conteúdo para acesso público. |
eu_rights_str_mv |
openAccess |
dc.format.none.fl_str_mv |
application/pdf |
dc.coverage.none.fl_str_mv |
|
dc.publisher.none.fl_str_mv |
Biblioteca Digitais de Teses e Dissertações da USP |
publisher.none.fl_str_mv |
Biblioteca Digitais de Teses e Dissertações da USP |
dc.source.none.fl_str_mv |
reponame:Biblioteca Digital de Teses e Dissertações da USP instname:Universidade de São Paulo (USP) instacron:USP |
instname_str |
Universidade de São Paulo (USP) |
instacron_str |
USP |
institution |
USP |
reponame_str |
Biblioteca Digital de Teses e Dissertações da USP |
collection |
Biblioteca Digital de Teses e Dissertações da USP |
repository.name.fl_str_mv |
Biblioteca Digital de Teses e Dissertações da USP - Universidade de São Paulo (USP) |
repository.mail.fl_str_mv |
virginia@if.usp.br|| atendimento@aguia.usp.br||virginia@if.usp.br |
_version_ |
1809090270053007360 |