ALMA chemical survey of disk-outflow sources in Taurus (ALMA-DOT) VI:
  Accretion shocks in the disk of DG Tau and HL Tau
  Planet-forming disks are not isolated systems. Their interaction with the
surrounding medium affects their mass budget and chemical content. In the
context of the ALMA-DOT program, we obtained high-resolution maps of assorted
lines from six disks that are still partly embedded in their natal envelope. In
this work, we examine the SO and SO$_2$ emission that is detected from four
sources: DG Tau, HL Tau, IRAS 04302+2247, and T Tau. The comparison with CO,
HCO$^+$, and CS maps reveals that the SO and SO$_2$ emission originates at the
intersection between extended streamers and the planet-forming disk. Two
targets, DG Tau and HL Tau, offers clear cases of inflowing material inducing
an accretion shock on the disk material. The measured rotational temperatures
and radial velocities are consistent with this view. In contrast to younger
Class 0 sources, these shocks are confined to the specific disk region impacted
by the streamer. In HL Tau, the known accreting streamer induces a shock in the
disk outskirt, and the released SO and SO$_2$ molecules spiral toward the star
in a few hundreds years. These results suggest that shocks induced by late
accreting material may be common in the disks of young star-forming regions
with possible consequences on the chemical composition and mass content of the
disk. They also highlight the importance of SO and SO$_2$ line observations to
probe accretion shocks from a larger sample.
