Buchumschlag

Emission-line diagnostics for IMBHs in Dwarf Galaxies: accounting for black hole seeding and ultraluminous x-ray source excitation

Dwarf active galactic nuclei (AGN) serve as the ideal systems for identifying intermediate-mass black holes (IMBHs) down to the most elusive regimes (∼103-104M⊙). However, the ubiquitously metal-poor nature of dwarf galaxies gives rise to ultraluminous X-ray sources (ULXs) that can mimic the spectra...

Ausführliche Beschreibung

Gespeichert in:
Bibliographische Detailangaben
Hauptverfasser: Richardson, Chris (VerfasserIn) , Wels, Jordan (VerfasserIn) , Garofali, Kristen (VerfasserIn) , Levanti, Julianna M. (VerfasserIn) , Lebouteiller, Vianney (VerfasserIn) , Lehmer, Bret (VerfasserIn) , Basu-Zych, Antara (VerfasserIn) , Berg, Danielle (VerfasserIn) , Bellovary, Jillian M. (VerfasserIn) , Chisholm, John (VerfasserIn) , Kannappan, Sheila J. (VerfasserIn) , Lambrides, Erini (VerfasserIn) , Polimera, Mugdha S. (VerfasserIn) , Ramambason, Lise (VerfasserIn) , Varese, Maxime (VerfasserIn) , Vivona, Thomas (VerfasserIn)
Dokumenttyp: Article (Journal)
Sprache:Englisch
Veröffentlicht: 2025 November 1
In: The astrophysical journal
Year: 2025, Jahrgang: 993, Pages: 1-30
ISSN:1538-4357
DOI:10.3847/1538-4357/adf215
Online-Zugang:Verlag, kostenfrei, Volltext: https://doi.org/10.3847/1538-4357/adf215
Volltext
Verfasserangaben:Chris T. Richardson, Jordan Wels, Kristen Garofali, Julianna M. Levanti, Vianney Lebouteiller, Bret Lehmer, Antara Basu-Zych, Danielle Berg, Jillian M. Bellovary, John Chisholm, Sheila J. Kannappan, Erini Lambrides, Mugdha S. Polimera, Lise Ramambason, Maxime Varese, and Thomas Vivona
Beschreibung
Zusammenfassung:Dwarf active galactic nuclei (AGN) serve as the ideal systems for identifying intermediate-mass black holes (IMBHs) down to the most elusive regimes (∼103-104M⊙). However, the ubiquitously metal-poor nature of dwarf galaxies gives rise to ultraluminous X-ray sources (ULXs) that can mimic the spectral signatures of IMBH excitation. We present a novel photoionization model suite that simultaneously incorporates IMBHs and ULXs in a metal-poor, highly star-forming environment. We account for changes in MBH according to formation seeding channels and metallicity, and changes in ULX populations with poststarburst age and metallicity. We find that broadband X-rays and UV emission lines are insensitive to MBH and largely unable to distinguish between ULXs and IMBHs. Many optical diagnostic diagrams cannot correctly identify dwarf AGN. The notable exceptions include He II λ4686 and [O I] λ6300, for which we redefine typical demarcations to account for ULX contributions. Emission lines in the mid-IR show the most promise in separating stellar, ULX, IMBH, and shock excitation while presenting sensitivity to MBH and fAGN. Overall, our results expose the potential biases in identifying and characterizing dwarf AGN purely on strong-line ratios and diagnostic diagrams rather than holistically evaluating the entire spectrum. As a proof of concept, we argue that recently discovered overmassive black holes (BHs) in high-z JWST AGN might not represent the overall BH population, with many galaxies in these samples potentially being falsely classified as purely star forming.
Beschreibung:Veröffentlicht: 30. Oktober 2025
Gesehen am 15.12.2025
Beschreibung:Online Resource
ISSN:1538-4357
DOI:10.3847/1538-4357/adf215

Ähnliche Einträge