Deep Huddle Space Telescope¹/Planetary Camera imaging of a young compact radio galaxy at z = 2.390

We present deep 63-orbit Hubble Space Telescope/Planetary Camera images at ∼0″.06 FWHM resolution in the filters B₄₅₀, V₆₀₆, and I₈₁₄ - as well as in redshifted Lyα - of the radio source 53W002, a compact narrow-line galaxy at z = 2.390 from the Leiden-Berkeley Deep Survey. These images allow us to distinguish several morphological components: (1) an unresolved nuclear point source (≲500 pc at z = 2.390 for H₀ = 75, q₀ = 0), likely the central active galactic nucleus (AGN) that contains ≲20%-25% of the total light in BVI; (2) a compact continuum core (r_e ≃ 0″.05); (3) a more extended envelope with an r^1/4-like light profile and r_e ≃ 0″.25 (∼2 kpc); (4) two blue "clouds" roughly colinear across the nucleus, aligned with the radio source axis and contained well within the size of the radio source. The (B - I) color maps may suggest a narrow dust lane crossing between the nucleus and the smaller blue cloud. The radio source is not smaller than the distance between the blue continuum clouds and coincides with a bright Lyα "arc" in the western cloud, suggesting that jet-induced star formation could cause both blue clouds, except the outer parts of the western cloud. The shape of this larger blue cloud suggests reflected AGN continuum light shining through a cone (plus reradiated Lyα in emission). The Owens Valley Radio Observatory interferometric CO detection (Scoville et al.) on both sides of 53W002 - and in the same direction as the continuum clouds and the radio jet - also suggests a star-bursting region induced by its radio jet, at least in the inner parts. Hence, both mechanisms likely play a role in the "alignment effect." Even at radio powers ∼1.5 dex fainter than the 3CR sources, we thus find many of the same aligned features and complex morphology, although at much smaller angular scales and lower optical-UV luminosities. We discuss the consequences for 53W002's formation in the context of the 16 subgalactic objects at z ≃ 2.40 around 53W002 (Pascarelle et al.).