Transient Survey Rates for Orphan Afterglows from Compact Merger Jets

Understand

Orphan afterglows from short $\gamma$-ray bursts (GRB) are potential candidates for electromagnetic (EM) counterpart searches to gravitational wave (GW) detected neutron star or neutron star black hole mergers.

• Various jet dynamical and structure models have been proposed that can be tested by the detection of a large sample of GW-EM counterparts.
• We make predictions for the expected rate of optical transients from these jet models for future survey telescopes, without a GW or GRB trigger.
• A sample of merger jets is generated in the redshift limits $0\leq z\leq 3.0$, and the expected peak $r$-band flux and timescale above the LSST or ZTF detection threshold, $m_r=24.5$ and $20.4$ respectively, is calculated.