Searching for Lya halos around RL quasars
The exploration of AGN and quasars in the first few billion years of cosmic history started with the advent of large-area digital sky surveys like the Sloan Digital Sky Survey (SDSS, e.g., York et al.,2000). This resulted in the first discoveries of quasars at 𝑧 > 5 (e.g., Fan et al., 2001). The study of high redshift quasars has provided fundamental knowledge on the first galaxies and SMBHs, which are currently, more than 500 at 𝑧 > 5.6, most of which are located in the Northern Hemisphere (e.g., Fan et al., 2023). Those observations firstly confirmed the existence of SMBHs with masses up to a few billion 𝑀⊙ within 1 billion years after the Big Bang, showing consistent rest UV/optical spectra with low redshift powerful quasars. Secondly, sub-mm observations showed that these quasars are hosted in massive, gas-rich, and highly star-forming galaxies (e.g., Decarli et al., 2018). These massive galaxies are thought to be fed by large amounts of gas (T ∼ 104 K) through the Circumgalactic Medium (CGM), which can be emitted via the Ly𝛼 line (e.g., Cantalupo et al., 2014). Additionally, the study of intergalactic medium (IGM) absorption features in quasar spectra established the end of the epoch of reionization between redshift 5 and 6 (𝑧 ∼ 5.3; Fan et al., 2023; Bosman et al., 2023) The CGM is composed by the gas surrounding galaxies inside the virial radii but outside of the galaxy disks (Tumlinson et al., 2017). The gas present in the CGM plays a crucial role in galaxy evolution. It serves as the fuel for star formation, facilitates galactic feedback and recycling, and regulates the gas supply of galaxies.
But how different are the diffuse gas structures around RL and RQ quasars, and does the powerful jet found in RL quasars interact strongly with the CGM?
This project aims to study Lyman Alpha Halos (LAHs) around 18 high-redshift (3.6 < z < 6.2) RL quasars using the Multi Unit Spectroscopic Explorer (MUSE). MUSE is an optical integral-field spectrograph with a large (60x60 arcmin) field of view on board the Very Large Telescope (VLT). I am comparing the properties of any LAHs found around the RL sample, e.g., luminosities, Lya Full-Width-Half-Maximum (FWHM), kinematics, and morphology, with those surrounding RQ quasars (e.g. Farina et al. 2019, Drake et al. 2019, Arrigoni-Battaia et al. 2019). This project will help to place radio jets in the context of galaxy and quasar evolution in the early universe, as well as study any interaction between the radio jets and the gas reservoirs in the quasar CGM. To do that firstly the RL quasars collected data needs to be reduced, Point Spread Function (PSF) subtracted, and afterward studied in detail to discover diffuse CGM structures around it. We have already discovered 8 new LAHs, nextly I am going to do a deep comparison of those objects with the similar structures around RQ ones. The paper will be ready to be submitted soon.
