| Autor: |
Jeremiah D. Paul, Richard M. Plotkin, W. N. Brandt, Christopher H. Ellis, Elena Gallo, Jenny E. Greene, Luis C. Ho, Amy E. Kimball, Daryl Haggard |
| Jazyk: |
angličtina |
| Rok vydání: |
2024 |
| Předmět: |
|
| Zdroj: |
The Astrophysical Journal, Vol 974, Iss 1, p 66 (2024) |
| Druh dokumentu: |
article |
| ISSN: |
1538-4357 |
| DOI: |
10.3847/1538-4357/ad67d1 |
| Popis: |
The supermassive black holes ( M _BH ∼ 10 ^6 –10 ^10 M _⊙ ) that power luminous active galactic nuclei (AGNs), i.e., quasars, generally show a correlation between thermal disk emission in the ultraviolet (UV) and coronal emission in hard X-rays. In contrast, some “massive” black holes (mBHs; M _BH ∼ 10 ^5 –10 ^6 M _⊙ ) in low-mass galaxies present curious X-ray properties with coronal radiative output up to 100× weaker than expected. To examine this issue, we present a pilot study incorporating Very Large Array radio observations of a sample of 18 high-accretion-rate (Eddington ratios L _bol / L _Edd > 0.1), mBH-powered AGNs ( M _BH ∼ 10 ^6 M _⊙ ) with Chandra X-ray coverage. Empirical correlations previously revealed in samples of radio-quiet, high-Eddington AGNs indicate that the radio–X-ray luminosity ratio, L _R / L _X , is approximately constant. Through multiwavelength analysis, we instead find that the X-ray-weaker mBHs in our sample tend toward larger values of L _R / L _X even though they remain radio-quiet per their optical–UV properties. This trend results in a tentative but highly intriguing correlation between L _R / L _X and X-ray weakness, which we argue is consistent with a scenario in which X-rays may be preferentially obscured from our line of sight by a “slim” accretion disk. We compare this observation to weak emission-line quasars (AGNs with exceptionally weak broad-line emission and a significant X-ray-weak fraction) and conclude by suggesting that our results may offer a new observational signature for finding high-accretion-rate AGNs. |
| Databáze: |
Directory of Open Access Journals |
| Externí odkaz: |
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