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NASA Goddard Space Flight CenterAnna Trindade FalcãoMultiwavelength astrophysicist · Black-hole winds · AGN feedback
Continuum-subtracted HST/ACS/WFC [O III] λ5007 panel for PG 0026+129 from published Figure 1. Logarithmic flux colors and contours show a comparatively symmetric extended narrow-line region with measured radius 4.7 ± 0.1 kpc and b/a = 1.4. A white cross marks the continuum peak; solid, dash-dot, and dotted outlines mark the measured [O III] radius, 1 kpc, and 2 kpc. Narrow southern and western structures may include diffraction-spike residuals. The image contains no gas-velocity measurement.
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Research article · 2024

Hubble Space Telescope observations of nearby type 1 quasars. I. Characterization of the extended [O III] 5007 Å emission

MNRAS 535(1), 621–633 (2024)

Paper-derived processed HST/ACS observational figure · Published Figure 1, PG 0026+129 panel

Published Figure 1, PG 0026+129 panel. Continuum-subtracted HST/ACS/WFC [O III] λ5007 imaging from FR551N on-band and FR647M continuum observations. Flux contours begin at 3σsky and increase by powers of two. The white cross marks the continuum-flux peak adopted as the nucleus; the solid outline marks the measured [O III] radius, while dash-dot and dotted circles mark 1 and 2 kpc. The measured narrow-line-region radius is 4.7 ± 0.1 kpc and b/a = 1.4. Narrow southern and western structures may be affected by diffraction spikes, while the elliptical emission within the southern arm is detected. This image measures projected [O III] morphology and extent, not gas kinematics, outflow velocity, causal feedback, or evolutionary stage.

Trindade Falcão et al. 2024, “Hubble Space Telescope observations of nearby type 1 quasars. I. Characterization of the extended [O III] 5007 Å emission,” MNRAS 535, issue 1, 621–633, DOI: 10.1093/mnras/stae2412, CC BY 4.0. Published Figure 1 PG 0026+129 panel rasterized at 150 dpi and converted to lossy WebP for web presentation. HST: NASA/ESA; figure and image processing: Trindade Falcão et al. Exact WebP encoder settings are not recorded and deterministic regeneration is not claimed.

Research summary

The extent and structure of ionized gas in nearby type 1 quasars

This paper presents continuum-subtracted HST/ACS/WFC [O III] λ5007 imaging of seven bright, radio-quiet PG type 1 quasars from program 15281: PG 0026+129, PG 0052+251, PG 0157+001, PG 0953+414, PG 1012+008, PG 1049−005, and PG 1307+085. All seven show projected extended narrow-line regions with measured radii of approximately 3–9 kpc; four are comparatively symmetric and three asymmetric under the paper's axial-ratio measure. The combined AGN size–luminosity relation has slope 0.51 ± 0.03, consistent with the simple photoionization expectation, while separate type 1 and type 2 fits give 0.57 ± 0.05 and 0.48 ± 0.02. Maximum narrow-line-region sizes and ionized-gas masses are model-dependent on the adopted ionization parameter, density, spectral energy distribution, abundances, bolometric correction, column density, and geometry. The proposed progression from compact type 2 to extended type 1 narrow-line regions is an evolutionary interpretation, not an observed temporal sequence. This imaging paper does not measure a gas velocity field, outflow rate, kinetic power, coupling efficiency, or causal feedback; later type 2 quasar physical-properties and kinematics papers provide separate measurements and must not be read as results of this study.