_version_ 1866912583506722816
author Lambrides, Erini
Larson, Rebecca
Hutchison, Taylor
Haro, Pablo Arrabal
Wang, Bingjie
Welch, Brian
Kocevski, Dale D.
Richardson, Chris T.
Papovich, Casey
Trump, Jonathan R.
Bosman, Sarah E. I.
Rigby, Jane R.
Finkelstein, Steven L.
Barro, Guillermo
Antwi-Danso, Jacqueline
Long, Arianna
Taylor, Anthony J.
Cann, Jenna
McKaig, Jeffrey
Koekemoer, Anton M.
Cleri, Nikko J.
Akins, Hollis B.
Bagley, Mic B.
Berg, Danielle A.
Bromm, Volker
Chisholm, John
Chworowsky, Katherine
Coffin, Sadie
Cooper, M. C.
Cooper, Olivia
Cox, Isa
Dickinson, Mark
Ferguson, Henry C.
Franco, Maximilien
Gardner, Jonathan P.
Grogin, Norman A.
Hirschmann, Michaela
Huertas-Company, Marc
Jung, Intae
Kartaltepe, Jeyhan S.
Khullar, Gourav P.
Lucas, Ray A.
McGrath, Elizabeth J.
Morales, Alexa M.
Olivier, Grace M.
Ortiz, Óscar A. Chávez
Pérez-González, Pablo G.
Pirzkal, Norbert
Somerville, Rachel S.
Vanderhoof, Brittany
Weiner, Benjamin J.
Yung, L. Y. Aaron
Zavala, Jorge A.
author_facet Lambrides, Erini
Larson, Rebecca
Hutchison, Taylor
Haro, Pablo Arrabal
Wang, Bingjie
Welch, Brian
Kocevski, Dale D.
Richardson, Chris T.
Papovich, Casey
Trump, Jonathan R.
Bosman, Sarah E. I.
Rigby, Jane R.
Finkelstein, Steven L.
Barro, Guillermo
Antwi-Danso, Jacqueline
Long, Arianna
Taylor, Anthony J.
Cann, Jenna
McKaig, Jeffrey
Koekemoer, Anton M.
Cleri, Nikko J.
Akins, Hollis B.
Bagley, Mic B.
Berg, Danielle A.
Bromm, Volker
Chisholm, John
Chworowsky, Katherine
Coffin, Sadie
Cooper, M. C.
Cooper, Olivia
Cox, Isa
Dickinson, Mark
Ferguson, Henry C.
Franco, Maximilien
Gardner, Jonathan P.
Grogin, Norman A.
Hirschmann, Michaela
Huertas-Company, Marc
Jung, Intae
Kartaltepe, Jeyhan S.
Khullar, Gourav P.
Lucas, Ray A.
McGrath, Elizabeth J.
Morales, Alexa M.
Olivier, Grace M.
Ortiz, Óscar A. Chávez
Pérez-González, Pablo G.
Pirzkal, Norbert
Somerville, Rachel S.
Vanderhoof, Brittany
Weiner, Benjamin J.
Yung, L. Y. Aaron
Zavala, Jorge A.
contents Some of the most puzzling discoveries of NASA's JWST in the early Universe surround the surprising abundance of compact red sources, which show peculiar continuum shapes and broad hydrogen spectral lines. These sources, dubbed ``Little Red Dots'' or LRDs, have been the subject of intense inquiry in the literature. Any of the proposed explanations, from accreting super-massive black holes ensconced in ultra-dense gas to extremely compact star-systems, has significant implications for the earliest phases of galaxy evolution. Part of the difficulty in concretely identifying the physical mechanisms that drive their rest ultra-violet/optical spectral properties is the lack of bona fide signatures -- either star-formation or accreting super-massive black hole, that uniquely discriminate between competing interpretations. In this work, we report the discovery of several spectral features that strongly favor the existence of an accreting super-massive black hole in an LRD witnessed in the first 800 Myr of cosmic time, including several rare iron transitions and a possible [FeVII]. Additionally, we report on the properties of significant Balmer absorption and find that the small widths and relative depths of the absorption feature suggest the source of the absorber is at or beyond the outer edge of the broad-line region and does it fully cover the accreting SMBH in the center of the system. The detection of these iron features, coupled with the properties of the Balmer absorption, unveils an alternative scenario for LRDs -- one where there are direct sight-lines from the accretion disk to gas on scales at (or beyond) the broad-line gas region.
format Preprint
id arxiv_https___arxiv_org_abs_2509_09607
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Discovery of Multiply Ionized Iron Emission Powered by an Active Galactic Nucleus in a z~7 Little Red Dot
Lambrides, Erini
Larson, Rebecca
Hutchison, Taylor
Haro, Pablo Arrabal
Wang, Bingjie
Welch, Brian
Kocevski, Dale D.
Richardson, Chris T.
Papovich, Casey
Trump, Jonathan R.
Bosman, Sarah E. I.
Rigby, Jane R.
Finkelstein, Steven L.
Barro, Guillermo
Antwi-Danso, Jacqueline
Long, Arianna
Taylor, Anthony J.
Cann, Jenna
McKaig, Jeffrey
Koekemoer, Anton M.
Cleri, Nikko J.
Akins, Hollis B.
Bagley, Mic B.
Berg, Danielle A.
Bromm, Volker
Chisholm, John
Chworowsky, Katherine
Coffin, Sadie
Cooper, M. C.
Cooper, Olivia
Cox, Isa
Dickinson, Mark
Ferguson, Henry C.
Franco, Maximilien
Gardner, Jonathan P.
Grogin, Norman A.
Hirschmann, Michaela
Huertas-Company, Marc
Jung, Intae
Kartaltepe, Jeyhan S.
Khullar, Gourav P.
Lucas, Ray A.
McGrath, Elizabeth J.
Morales, Alexa M.
Olivier, Grace M.
Ortiz, Óscar A. Chávez
Pérez-González, Pablo G.
Pirzkal, Norbert
Somerville, Rachel S.
Vanderhoof, Brittany
Weiner, Benjamin J.
Yung, L. Y. Aaron
Zavala, Jorge A.
Astrophysics of Galaxies
Some of the most puzzling discoveries of NASA's JWST in the early Universe surround the surprising abundance of compact red sources, which show peculiar continuum shapes and broad hydrogen spectral lines. These sources, dubbed ``Little Red Dots'' or LRDs, have been the subject of intense inquiry in the literature. Any of the proposed explanations, from accreting super-massive black holes ensconced in ultra-dense gas to extremely compact star-systems, has significant implications for the earliest phases of galaxy evolution. Part of the difficulty in concretely identifying the physical mechanisms that drive their rest ultra-violet/optical spectral properties is the lack of bona fide signatures -- either star-formation or accreting super-massive black hole, that uniquely discriminate between competing interpretations. In this work, we report the discovery of several spectral features that strongly favor the existence of an accreting super-massive black hole in an LRD witnessed in the first 800 Myr of cosmic time, including several rare iron transitions and a possible [FeVII]. Additionally, we report on the properties of significant Balmer absorption and find that the small widths and relative depths of the absorption feature suggest the source of the absorber is at or beyond the outer edge of the broad-line region and does it fully cover the accreting SMBH in the center of the system. The detection of these iron features, coupled with the properties of the Balmer absorption, unveils an alternative scenario for LRDs -- one where there are direct sight-lines from the accretion disk to gas on scales at (or beyond) the broad-line gas region.
title Discovery of Multiply Ionized Iron Emission Powered by an Active Galactic Nucleus in a z~7 Little Red Dot
topic Astrophysics of Galaxies
url https://arxiv.org/abs/2509.09607