Here There Be (Dusty) Monsters: High-redshift Active Galactic Nuclei Are Dustier than Their Hosts
JWST spectroscopy has discovered a population of z ≳ 3.5 galaxies with broad Balmer emission lines and narrow forbidden lines that are consistent with hosting active galactic nuclei (AGN). Many of these systems, now known as “little red dots,” are compact and have unique colors that are very red in...
Saved in:
| Main Authors: | , , , , , , , , , , , , , , , , , |
|---|---|
| Format: | Article |
| Language: | English |
| Published: |
IOP Publishing
2025-01-01
|
| Series: | The Astrophysical Journal |
| Subjects: | |
| Online Access: | https://doi.org/10.3847/1538-4357/addac4 |
| Tags: |
Add Tag
No Tags, Be the first to tag this record!
|
| _version_ | 1850103521168326656 |
|---|---|
| author | Madisyn Brooks Raymond C. Simons Jonathan R. Trump Anthony J. Taylor Micaela B. Bagley Bren Backhaus Kelcey Davis Véronique Buat Nikko J. Cleri Alexander de la Vega Steven L. Finkelstein Michaela Hirschmann Benne W. Holwerda Dale D. Kocevski Anton M. Koekemoer Ray A. Lucas Fabio Pacucci Lise-Marie Seillé |
| author_facet | Madisyn Brooks Raymond C. Simons Jonathan R. Trump Anthony J. Taylor Micaela B. Bagley Bren Backhaus Kelcey Davis Véronique Buat Nikko J. Cleri Alexander de la Vega Steven L. Finkelstein Michaela Hirschmann Benne W. Holwerda Dale D. Kocevski Anton M. Koekemoer Ray A. Lucas Fabio Pacucci Lise-Marie Seillé |
| author_sort | Madisyn Brooks |
| collection | DOAJ |
| description | JWST spectroscopy has discovered a population of z ≳ 3.5 galaxies with broad Balmer emission lines and narrow forbidden lines that are consistent with hosting active galactic nuclei (AGN). Many of these systems, now known as “little red dots,” are compact and have unique colors that are very red in the optical/near-infrared and blue in the ultraviolet. The relative contribution of galaxy starlight and AGN to these systems remains uncertain, especially for the galaxies with unusual blue+red spectral energy distributions. In this work, we use Balmer decrements to measure the independent dust attenuation of the broad and narrow emission-line components of a sample of 29 broad-line AGN identified from three public JWST spectroscopy surveys: CEERS, JADES, and RUBIES. Stacking the narrow components from the spectra of 25 sources with broad H α and no broad H β results in a median narrow H α /H β = $2.4{7}_{-0.05}^{+0.05}$ (consistent with A _v = 0) and broad H α /H β >8.85 ( A _v > 3.63). The narrow and broad Balmer decrements imply little to no attenuation of the narrow emission lines, which are consistent with being powered by star formation and located on larger physical scales. Meanwhile, the lower limit in the broad H α /H β decrement, with broad H β undetected in the stacked spectrum of 25 broad H α AGN, implies significant dust attenuation of the broad-line emitting region that is presumably associated with the central AGN. Our results indicate that these systems, on average, are consistent with heavily dust-attenuated AGN powering the red parts of their SED, while their blue UV emission is powered by unattenuated star formation in the host galaxy. |
| format | Article |
| id | doaj-art-16ebf034d5184a0c9dc861d99a5fcf5c |
| institution | DOAJ |
| issn | 1538-4357 |
| language | English |
| publishDate | 2025-01-01 |
| publisher | IOP Publishing |
| record_format | Article |
| series | The Astrophysical Journal |
| spelling | doaj-art-16ebf034d5184a0c9dc861d99a5fcf5c2025-08-20T02:39:32ZengIOP PublishingThe Astrophysical Journal1538-43572025-01-01986217710.3847/1538-4357/addac4Here There Be (Dusty) Monsters: High-redshift Active Galactic Nuclei Are Dustier than Their HostsMadisyn Brooks0https://orcid.org/0000-0001-5384-3616Raymond C. Simons1https://orcid.org/0000-0002-6386-7299Jonathan R. Trump2https://orcid.org/0000-0002-1410-0470Anthony J. Taylor3https://orcid.org/0000-0003-1282-7454Micaela B. Bagley4https://orcid.org/0000-0002-9921-9218Bren Backhaus5https://orcid.org/0000-0001-8534-7502Kelcey Davis6https://orcid.org/0000-0001-8047-8351Véronique Buat7https://orcid.org/0000-0003-3441-903XNikko J. Cleri8https://orcid.org/0000-0001-7151-009XAlexander de la Vega9https://orcid.org/0000-0002-6219-5558Steven L. Finkelstein10https://orcid.org/0000-0001-8519-1130Michaela Hirschmann11https://orcid.org/0000-0002-3301-3321Benne W. Holwerda12https://orcid.org/0000-0002-4884-6756Dale D. Kocevski13https://orcid.org/0000-0002-8360-3880Anton M. Koekemoer14https://orcid.org/0000-0002-6610-2048Ray A. Lucas15https://orcid.org/0000-0003-1581-7825Fabio Pacucci16https://orcid.org/0000-0001-9879-7780Lise-Marie Seillé17https://orcid.org/0000-0001-7755-4755Department of Physics, 196A Auditorium Road, Unit 3046, University of Connecticut , Storrs, CT 06269, USADepartment of Physics, 196A Auditorium Road, Unit 3046, University of Connecticut , Storrs, CT 06269, USA; Department of Engineering and Physics, Providence College , 1 Cunningham Square, Providence, RI 02918, USADepartment of Physics, 196A Auditorium Road, Unit 3046, University of Connecticut , Storrs, CT 06269, USADepartment of Astronomy, The University of Texas at Austin , Austin, TX, USADepartment of Astronomy, The University of Texas at Austin , Austin, TX, USA; Astrophysics Science Division, NASA Goddard Space Flight Center , 8800 Greenbelt Road, Greenbelt, MD 20771, USADepartment of Physics and Astronomy, University of Kansas , Lawrence, KS 66045, USADepartment of Physics, 196A Auditorium Road, Unit 3046, University of Connecticut , Storrs, CT 06269, USAAix Marseille Univ , CNRS, CNES, LAM, Marseille, France; Institut Universitaire de France (IUF) , Paris, FranceDepartment of Astronomy and Astrophysics, The Pennsylvania State University , University Park, PA 16802, USA; Institute for Computational and Data Sciences, The Pennsylvania State University , University Park, PA 16802, USA; Institute for Gravitation and the Cosmos, The Pennsylvania State University , University Park, PA 16802, USADepartment of Physics and Astronomy, University of California , 900 University Avenue, Riverside, CA 92521, USADepartment of Astronomy, The University of Texas at Austin , Austin, TX, USA; Cosmic Frontier Center, The University of Texas at Austin , Austin, TX, USAInstitute of Physics , Laboratory of Galaxy Evolution, Ecole Polytechnique Fédérale de Lausanne (EPFL), Observatoire de Sauverny, 1290 Versoix, SwitzerlandDepartment of Physics, University of Louisville , Natural Science Building 102, Louisville, KY 40292, USADepartment of Physics and Astronomy, Colby College , Waterville, ME 04901, USASpace Telescope Science Institute , 3700 San Martin Drive, Baltimore, MD 21218, USASpace Telescope Science Institute , 3700 San Martin Drive, Baltimore, MD 21218, USACenter for Astrophysics ∣ Harvard & Smithsonian, 60 Garden Street, Cambridge, MA 02138, USA; Black Hole Initiative, Harvard University , 20 Garden Street, Cambridge, MA 02138, USAAix Marseille Univ , CNRS, CNES, LAM, Marseille, FranceJWST spectroscopy has discovered a population of z ≳ 3.5 galaxies with broad Balmer emission lines and narrow forbidden lines that are consistent with hosting active galactic nuclei (AGN). Many of these systems, now known as “little red dots,” are compact and have unique colors that are very red in the optical/near-infrared and blue in the ultraviolet. The relative contribution of galaxy starlight and AGN to these systems remains uncertain, especially for the galaxies with unusual blue+red spectral energy distributions. In this work, we use Balmer decrements to measure the independent dust attenuation of the broad and narrow emission-line components of a sample of 29 broad-line AGN identified from three public JWST spectroscopy surveys: CEERS, JADES, and RUBIES. Stacking the narrow components from the spectra of 25 sources with broad H α and no broad H β results in a median narrow H α /H β = $2.4{7}_{-0.05}^{+0.05}$ (consistent with A _v = 0) and broad H α /H β >8.85 ( A _v > 3.63). The narrow and broad Balmer decrements imply little to no attenuation of the narrow emission lines, which are consistent with being powered by star formation and located on larger physical scales. Meanwhile, the lower limit in the broad H α /H β decrement, with broad H β undetected in the stacked spectrum of 25 broad H α AGN, implies significant dust attenuation of the broad-line emitting region that is presumably associated with the central AGN. Our results indicate that these systems, on average, are consistent with heavily dust-attenuated AGN powering the red parts of their SED, while their blue UV emission is powered by unattenuated star formation in the host galaxy.https://doi.org/10.3847/1538-4357/addac4Active galactic nucleiAGN host galaxiesHigh-redshift galaxiesSupermassive black holesSpectroscopy |
| spellingShingle | Madisyn Brooks Raymond C. Simons Jonathan R. Trump Anthony J. Taylor Micaela B. Bagley Bren Backhaus Kelcey Davis Véronique Buat Nikko J. Cleri Alexander de la Vega Steven L. Finkelstein Michaela Hirschmann Benne W. Holwerda Dale D. Kocevski Anton M. Koekemoer Ray A. Lucas Fabio Pacucci Lise-Marie Seillé Here There Be (Dusty) Monsters: High-redshift Active Galactic Nuclei Are Dustier than Their Hosts The Astrophysical Journal Active galactic nuclei AGN host galaxies High-redshift galaxies Supermassive black holes Spectroscopy |
| title | Here There Be (Dusty) Monsters: High-redshift Active Galactic Nuclei Are Dustier than Their Hosts |
| title_full | Here There Be (Dusty) Monsters: High-redshift Active Galactic Nuclei Are Dustier than Their Hosts |
| title_fullStr | Here There Be (Dusty) Monsters: High-redshift Active Galactic Nuclei Are Dustier than Their Hosts |
| title_full_unstemmed | Here There Be (Dusty) Monsters: High-redshift Active Galactic Nuclei Are Dustier than Their Hosts |
| title_short | Here There Be (Dusty) Monsters: High-redshift Active Galactic Nuclei Are Dustier than Their Hosts |
| title_sort | here there be dusty monsters high redshift active galactic nuclei are dustier than their hosts |
| topic | Active galactic nuclei AGN host galaxies High-redshift galaxies Supermassive black holes Spectroscopy |
| url | https://doi.org/10.3847/1538-4357/addac4 |
| work_keys_str_mv | AT madisynbrooks heretherebedustymonstershighredshiftactivegalacticnucleiaredustierthantheirhosts AT raymondcsimons heretherebedustymonstershighredshiftactivegalacticnucleiaredustierthantheirhosts AT jonathanrtrump heretherebedustymonstershighredshiftactivegalacticnucleiaredustierthantheirhosts AT anthonyjtaylor heretherebedustymonstershighredshiftactivegalacticnucleiaredustierthantheirhosts AT micaelabbagley heretherebedustymonstershighredshiftactivegalacticnucleiaredustierthantheirhosts AT brenbackhaus heretherebedustymonstershighredshiftactivegalacticnucleiaredustierthantheirhosts AT kelceydavis heretherebedustymonstershighredshiftactivegalacticnucleiaredustierthantheirhosts AT veroniquebuat heretherebedustymonstershighredshiftactivegalacticnucleiaredustierthantheirhosts AT nikkojcleri heretherebedustymonstershighredshiftactivegalacticnucleiaredustierthantheirhosts AT alexanderdelavega heretherebedustymonstershighredshiftactivegalacticnucleiaredustierthantheirhosts AT stevenlfinkelstein heretherebedustymonstershighredshiftactivegalacticnucleiaredustierthantheirhosts AT michaelahirschmann heretherebedustymonstershighredshiftactivegalacticnucleiaredustierthantheirhosts AT bennewholwerda heretherebedustymonstershighredshiftactivegalacticnucleiaredustierthantheirhosts AT daledkocevski heretherebedustymonstershighredshiftactivegalacticnucleiaredustierthantheirhosts AT antonmkoekemoer heretherebedustymonstershighredshiftactivegalacticnucleiaredustierthantheirhosts AT rayalucas heretherebedustymonstershighredshiftactivegalacticnucleiaredustierthantheirhosts AT fabiopacucci heretherebedustymonstershighredshiftactivegalacticnucleiaredustierthantheirhosts AT lisemarieseille heretherebedustymonstershighredshiftactivegalacticnucleiaredustierthantheirhosts |