We discovered a giant, ≈70 kpc-scale nebula in [O II], Hβ, and [O III] around radio-quiet quasar at a redshift of z = 0.6282.
We conducted characterization to its galactic environment and found that the quasar resides in an unusually overdense environment for a radio-quiet system,
potential consisting of two groups which may be merging. We also found that the nebula exhibits largely quiescent kinematics and irregular morphology.
The nebula may arise primarily through interaction-related stripping of CGM/ISM of group members.
We found that the upper limits on the electron number density implied by the [O II] doublet ratio range from log(n_e /cm^−3) < 1.2 to 2.8.
However, the densities implied from the measured line ratios between different ions (e.g. [O II], [O III],
and [Ne V]) and photoionization simulations are often 10−400 times larger. This large discrepancy can be explained by quasar
variability on a time-scale of ≈10^4−10^5 yr. Our key figures can be viewed in INTERACTIVE MAPS.
We explored the origin of a giant nebula around a radio-loud quasar, 3C 57.
Our investigation reveals that 3C 57 resides in a sparse environment with only 6 galaxies, none of which are spatially and kinematically coincident with the majority of the nebula.
We also found the nebula exhibits a blueshifted-redshifted pattern with large velocity dispersion and multi-component emission features.
The observed active kinematics and redshifted-blueshifted morphology suggest that the nebula is unlikely to be solely rotating ISM/CGM gas from the host galaxy.
Instead, the nebula's characteristics indicate a more complex origin, potentially resulting from a combination of rotating gas and AGN feedback mechanisms.
We will explore the origin of 30 giant quasar nebulae in the CUBS+MUSEQuBES survey.
Differentiating between these origins relies on nebula morphology and gas kinematics.
Inflow-originated nebulae are expected to showcase filamentary structures extending ≈ 100 kpc,
while outflow-related cases typically display multi-component emission features with broad emission wings.
Nebulae originating from galaxy interactions often exhibit tidal-tail- and head-tail-like structures.
By distinguishing the origin of nebulae among inflows, outflows, and galaxy interactions,
this systematic study will provide fundamental insights toward the galactic ecosystems.