Taichi Uyama and Kantapon Jensangjun

From the calendar

To address controversial theories about planet formation and planet-disk interactions, directly imaging embedded planets in the disk provides critical information. However, the required 'contrast' between the hosting star and protoplanet is quite high, and it is technically difficult to achieve such a high contrast with existing ground-based telescopes, as there are extremely few reports of embedded protoplanets (even candidates). To address this situation, we obtained JWST/NIRCam coronagraphic data at 2 and 4 microns for one of the most promising systems to detect protoplanets, HD 163296. I will show the final post-processed results (Uyama et al. 2025) and explain what we found from the JWST data.

We investigate whether AGN-driven outflows affect the size of narrow-line regions (NLRs), traced by [O III] λ5007 emission. Using a method that combines broadband imaging and spectroscopic data, we construct [O III] maps for 2,009 nearby type-2 AGNs. Adopting a surface brightness threshold of 1.4 × 10⁻¹⁵ erg s⁻¹ cm⁻² arcsec⁻², the [O III] isophotal areas range from 3.7 to 224 kpc². A positive correlation is found between NLR size and AGN luminosity, which becomes stronger at higher surface brightness thresholds. Outflows are identified where the [O III] velocity dispersion exceeds 1.4 times the stellar velocity dispersion. At fixed luminosity, AGNs with and without outflows show no significant difference in NLR size, suggesting that photoionization—rather than outflows—governs the extent of the NLR.