Black Hole Journal Club

We meet every Tuesday at:

The Zoom link has been emailed to the group.

Agenda

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Discussed Papers:

Effects of ultra-fast outflows on X-ray time lags in AGN (Xu et al., 2024)
- They observe 3 AGN with UFOs between $0.03-0.3$ c
- Disk fluctuations in cold (soft) and hot (hard) X-rays
- Low frequency hard-lags suppression in UFO states
- Magnetically Driven Accretion Disk Winds and Ultra-fast Outflows in PG 1211+143 (Keigo et al., 2015)
The XRISM/Resolve view of the Fe K region of Cyg X-3 (XRISM Collaboration, 2024)
- Wind-focused BH
- Orbital period ~5hrs
X-Ray View of Little Red Dots: Do They Host Supermassive Black Holes? (Ananna et al., 2024)
- Large uncertanties
- Compton thick
  - X-ray column density $n_H\gtrsim10^{25}$ $\text{cm}^{-2}$
  - JWST inconsistent with $n_H\sim10^{21}$ $\text{cm}^{-2}$
- AGN interpretation prefered in UNCOVER Spectroscopy Confirms the Surprising Ubiquity of Active Galactic Nuclei in Red Sources at z > 5 (Greene et al., 2024) but SF could fit.
- A small and vigorous black hole in the early Universe (Maiolino et al., 2024)
  - SMBH faster growth than stellar mass

Keeping up to date with papers:

Discussed Papers:

The XRISM/Resolve view of the Fe K region of Cyg X-3 (XRISM Collaboration, 2024).
- Really nice detailed spectrum with a lot of Fe absorption and emission lines observed.
Little Red Dots: an abundant population of faint AGN at z∼5 revealed by the EIGER and FRESCO JWST surveys (Matthee, et al., 2024)
- A paper hinting towards the seeing early AGN feedback and early SMBH growth being highlt obscured.
Deep Chandra Observations of NGC 5728. III: Probing the High-Resolution X-ray Morphology and Multiphase ISM Interactions in the Circumnuclear Region (Falcao, et al., 2024)
- A paper looking at ISM interactions within a Seyfert 2 galaxy likely from X-ray binaries
Structural Decomposition of Merger-Free Galaxies Hosting Luminous AGNs (Fahey, et al., 2024)
- Investigates AGN evolution in merger-free galaxies. A weak correlations between bulge & SMBH masses, and for stellar & SMBH masses observed for disk-dominated galaxies.

Presented paper:

X-Ray View of Little Red Dots: Do They Host Supermassive Black Holes? (Ananna, et al., 2024)
- Unknown reason for JWST-observed 'little red dots', with flux either AGN dominated, young star formation dominated or both.
- Over 100 Chandra observations of lensing cluster Abell 2744 equating up to $\approx 2$ Ms or $\approx90$ Ms stacked.
- No significant detection until broad-line $H\alpha$ galaxies are stacked.
- Possibly Compton thick AGN to explain non-detections.
- Results from X-ray and NIR suggest scaling relations from virial relations may not be applicable at high redshift.
- LRDs likely either do not contain overmassive SMBHs or accrete at a low eddington rate.
Also discussed was UNCOVER Spectroscopy Confirms the Surprising Ubiquity of Active Galactic Nuclei in Red Sources at z > 5 (Greene, et al., 2024)
- Shows a absorbed component and either AGN scattering or star formation to contribute to the UV.