Opening the era of quasar host studies at high redshift with JWST

Xuheng Ding, John D. Silverman, Masafusa Onoue

Submitted on 7 September 2022


We measure the host galaxy properties of five quasars with z1.63.5 selected from SDSS and AEGIS, which fall within the JWST/HST CEERS survey area. A PSF library is constructed based on stars in the full field-of-view of the data and used with a 2-dimensional image modeling tool galight to decompose the quasar and its host with multi-band filters available for HST ACS+WFC3 and JWST NIRCAM (12 filters covering HST F606W to JWST F444W). As demonstrated, JWST provides the first capability to detect quasar hosts at z>3 and enables spatially-resolved studies of the underlying stellar populations at z2 within morphological structures (spiral arms, bar) not possible with HST. Overall, we find quasar hosts to be disk-like, lack merger signatures, and have sizes generally more compact than typical star-forming galaxies at their respective stellar, thus in agreement with results at lower redshifts. The fortuitous face-on orientation of SDSSJ1420+5300A at z=1.646 enables us to find higher star formation and younger ages in the central 24 kpc region relative to the outskirts, which may help explain the relatively compact nature of quasar hosts and pose a challenge to AGN feedback models.


Comment: 11 pages, 1 table, 6 figures; submitted to ApJ; Comments welcome

Subject: Astrophysics - Astrophysics of Galaxies