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NASA Goddard Space Flight CenterAnna Trindade FalcãoMultiwavelength astrophysicist · Black-hole winds · AGN feedback
Three-panel processed Chandra/ACIS-S Figure 2 of NGC 5728 in the 0.3–7 keV band. The upper-left panel shows the one-eighth-native-pixel merged image without display smoothing; the lower-left panel applies a four-image-pixel Gaussian; and the right panel is adaptively smoothed over 0.5–30 image-pixel scales with ten counts per kernel and 60 iterations. Circles mark excluded nonnuclear point sources, dashed circles show a 10 arcsec, approximately 2 kpc radius, and the right panel includes a 5 arcsec, approximately 1 kpc scale bar. Display smoothing enhances low-surface-brightness morphology but is not an independent resolution or physical-coupling measurement.
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Research article · 2023

Deep Chandra Observations of NGC 5728: Morphology and Spectral Properties of the Extended X-Ray Emission

ApJ 950, 143 (2023)

Paper-derived processed Chandra observational figure · Published Figure 2

Published-paper Figure 2. Merged 0.3–7 keV Chandra/ACIS-S imaging of NGC 5728. Upper left: the one-eighth-native-pixel merged image without display smoothing. Lower left: the same merged image smoothed with a four-image-pixel Gaussian. Right: the merged image adaptively smoothed with Gaussian scales of 0.5–30 image pixels, ten counts under the kernel, and 60 iterations. Marked nonnuclear point sources were excluded from the spectral analysis and surface-brightness profiles; dashed circles have a 10 arcsec, approximately 2 kpc radius, and the right panel includes a 5 arcsec, approximately 1 kpc scale bar. Display smoothing enhances low-surface-brightness morphology but is not an independent resolution or physical-coupling measurement.

Trindade Falcão et al. 2023, “Deep Chandra Observations of NGC 5728: Morphology and Spectral Properties of the Extended X-Ray Emission,” ApJ 950, 143, DOI: 10.3847/1538-4357/acd052, CC BY 4.0. Published Figure 2 rasterized and converted to WebP for web presentation. Chandra: NASA/CXC. This website derivative is authorized by Anna Trindade Falcão; exact transformation settings are not recorded and deterministic regeneration is not claimed.

Research summary

Energy-dependent extended X-ray emission in NGC 5728

Paper I analyzes eleven Chandra/ACIS-S observations of NGC 5728 totaling 260.8 ks. Registered, merged, one-eighth-native-pixel imaging and observation-specific CHART/MARX PSF comparisons show that the diffuse emission becomes less extended with increasing energy: soft emission extends approximately 2 kpc radially along the ionization bicone and approximately 1.4 kpc in the cross-cone direction, while hard-continuum and Fe Kα emission is resolved along the bicone but not established in the 3–6 keV cross-cone profile. Spectral fits to nuclear, bicone, and cross-cone regions require combinations of photoionized and, in the extended regions, thermal components; their parameters, fluxes, and inferred physical quantities are model dependent. Associations with shocks, jet–ISM interaction, clumpy-torus transmission, warm-absorber analogies, supernova remnants, or star-formation-related heating remain interpretations or alternatives. Paper I measures no X-ray or gas velocity field, does not establish causal feedback, and does not contain the later Paper II Fe-wing or Paper III multiwavelength circumnuclear results.