The AGN Fraction in Dwarf Galaxies from eROSITA: First Results and Future Prospects

dc.contributor.authorLatimer, Lilikoi J.
dc.contributor.authorReines, Amy E.
dc.contributor.authorBogdan, Akos
dc.contributor.authorKraft, Ralph
dc.date.accessioned2022-09-23T15:57:33Z
dc.date.available2022-09-23T15:57:33Z
dc.date.issued2021-12
dc.description.abstractDetermining the fraction of nearby dwarf galaxies hosting massive black holes (BHs) can inform our understanding of the origin of “seed” BHs at high redshift. Here we search for signatures of accreting massive BHs in a sample of dwarf galaxies (M ⋆ ≤ 3 × 109 M ⊙, z ≤ 0.15) selected from the NASA-Sloan Atlas (NSA) using X-ray observations from the eROSITA Final Equatorial Depth Survey (eFEDS). On average, our search is sensitive to active galactic nuclei (AGNs) in dwarf galaxies that are accreting at ≳1% of their Eddington luminosity. Of the ∼28,000 X-ray sources in eFEDS and the 495 dwarf galaxies in the NSA within the eFEDS footprint, we find six galaxies hosting possible active massive BHs. If the X-ray sources are indeed associated with the dwarf galaxies, the X-ray emission is above that expected from star formation, with X-ray source luminosities of L 0.5–8 keV ∼ 1039–40 erg s−1. Additionally, after accounting for chance alignments of background AGNs with dwarf galaxies, we estimate there are between zero and nine real associations between dwarf galaxies and X-ray sources in the eFEDS field at the 95% confidence level. From this we find an upper limit on the eFEDS-detected dwarf galaxy AGN fraction of ≤1.8%, which is broadly consistent with similar studies at other wavelengths. We extrapolate these findings from the eFEDS sky coverage to the planned eROSITA All-Sky Survey and estimate that upon completion, the all-sky survey could yield as many as ∼1350 AGN candidates in dwarf galaxies at low redshift.en_US
dc.identifier.citationLatimer, C. J., Reines, A. E., Bogdan, A., & Kraft, R. (2021). The AGN fraction in dwarf galaxies from eROSITA: first results and future prospects. The Astrophysical Journal Letters, 922(2), L40.en_US
dc.identifier.issn2041-8205
dc.identifier.urihttps://scholarworks.montana.edu/handle/1/17212
dc.language.isoen_USen_US
dc.publisherAmerican Astronomical Societyen_US
dc.rightscc-byen_US
dc.rights.urihttps://creativecommons.org/licenses/by/4.0/en_US
dc.subjectAGN host galaxiesen_US
dc.subjectdwarf galaxiesen_US
dc.subjectX-ray active galactic nucleien_US
dc.titleThe AGN Fraction in Dwarf Galaxies from eROSITA: First Results and Future Prospectsen_US
dc.typeArticleen_US
mus.citation.extentfirstpage1en_US
mus.citation.extentlastpage6en_US
mus.citation.issue2en_US
mus.citation.journaltitleThe Astrophysical Journal Lettersen_US
mus.citation.volume922en_US
mus.data.thumbpage3en_US
mus.identifier.doi10.3847/2041-8213/ac3af6en_US
mus.relation.collegeCollege of Letters & Scienceen_US
mus.relation.departmentPhysics.en_US
mus.relation.universityMontana State University - Bozemanen_US

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