Active galactic nucleus (AGN) disks have been proposed as promising locations for the mergers of stellar-mass black hole binaries (BBHs). Much recent work has been done on this merger channel, but the majority focuses on stellar-mass black holes (BHs) orbiting in the prograde direction. Little work has been done to examine the impact of retrograde orbiters (ROs) on the formation and mergers of BBHs in AGN disks. Quantifying the retrograde contribution is important, as roughly half of all orbiters should initially be on retrograde orbits when the disk forms. We perform an analytic calculation of the evolution of ROs in an AGN disk. Because this evolution could cause the orbits of ROs to cross those of prograde BBHs, we derive the collision rate between a given RO and a given BBH orbiting in the prograde direction. In the examples given here, ROs in the inner region of the disk experience a rapid decrease in the semimajor axis of their orbits while also becoming highly eccentric in less than a million years. This rapid orbital evolution could lead to extreme mass ratio inspirals detectable by the Laser Interferometer Space Antenna. The collision rates of our example ROs with prograde BBHs in the migration trap depend strongly on the volume of the inner radiation-pressure-dominated region, which depends on the mass of the supermassive black hole (SMBH). Rates are lowest for larger-mass SMBHs, which dominate the AGN merger channel, suggesting that merger rates for this channel may not be significantly altered by ROs.

主动星系核（AGN）磁盘已被建议作为恒星质量黑洞二进制（BBH）合并的有希望的位置。关于这一合并渠道的最新工作已经完成，但大多数都集中在沿推进方向旋转的恒星质量黑洞（BH）上。几乎没有工作来研究逆行轨道器（RO）对AGN磁盘中BBH的形成和合并的影响。量化逆行贡献很重要，因为当磁盘形成时，大约有一半的轨道器最初应位于逆行轨道上。我们对AGN磁盘中RO的演变进行分析计算。因为这种演化可能导致RO的轨道越过正向BBH的轨道，所以我们得出了一个给定的RO与沿BB向前的给定BBH轨道之间的碰撞率。在此处给出的示例中，磁盘内部区域的RO在其轨道的半长轴方向上迅速减小，同时在不到一百万年的时间里也变得高度偏心。这种快速的轨道演化可能会导致激光干涉仪空间天线检测到极高的质量比吸气。我们的示例RO与迁移阱中的BBH呈正向碰撞的速率主要取决于内部辐射压力主导区域的体积，该体积取决于超大质量黑洞（SMBH）的质量。大质量SMBH的利率最低，这在AGN合并渠道中占主导地位，这表明该渠道的合并率可能不会受到RO的明显改变。这种快速的轨道演变可能会导致激光干涉仪空间天线检测到极高的质量比吸气。我们的示例RO与迁移阱中的BBH呈正向碰撞的速率主要取决于内部辐射压力主导区域的体积，该体积取决于超大质量黑洞（SMBH）的质量。大质量SMBH的利率最低，这在AGN合并渠道中占主导地位，这表明该渠道的合并率可能不会受到RO的明显改变。这种快速的轨道演化可能会导致激光干涉仪空间天线检测到极高的质量比吸气。我们的示例RO与迁移阱中的BBH呈正向碰撞的速率主要取决于内部辐射压力主导区域的体积，该体积取决于超大质量黑洞（SMBH）的质量。大质量SMBH的利率最低，这在AGN合并渠道中占主导地位，这表明该渠道的合并率可能不会受到RO的明显改变。