This work investigates variations in the star formation rate during galaxy collisions when the initial conditions of velocity and gas mass are altered. For this purpose, hydrodynamic simulations were performed using the GADGET-4 code, with initial conditions generated by the Galstep and SnapshotJoiner programs. Systems of two galaxies on a head-on collision course were modeled with relative initial velocities ranging from 100 km/s to 1000 km/s, considering two scenarios: the first with identical galaxies, and the second with galaxies of different sizes. In simulations of systems with higher initial relative velocities, both found more intense peaks in the star formation rate, triggered by the first contact of the collision, followed by a strong decline caused by gas dispersion. In contrast, for systems with lower initial velocities, mergers between galaxies were observed, leading to multiple peaks in the star formation rate. A greater initial distance between galaxies has also been linked to whether or not the galaxy system merges, since it implies longer timescales for gravitational action, which leads to higher relative velocities at the moment of collision. Furthermore, the star formation rate in galaxies was found to have a clear dependence on initial gas content. Furthermore, the initial gas content in galaxies was found to have a clear dependence on star formation rates. Overall, our results show that the relative impact velocity, the initial distance between the galaxies, and the gas content are important parameters for analyzing the star formation rate in colliding galaxies.

翻译：本研究探讨了当初始速度与气体质量条件改变时，星系碰撞过程中恒星形成率的变化规律。为此，我们采用GADGET-4代码进行流体动力学模拟，并通过Galstep与SnapshotJoiner程序生成初始条件。研究模拟了两星系沿正碰轨道的系统，相对初始速度范围设定为100 km/s至1000 km/s，并考虑两种情景：第一种为相同质量的星系，第二种为不同尺寸的星系。在较高初始相对速度的模拟系统中，均发现由碰撞首次接触触发的恒星形成率峰值更为剧烈，随后因气体弥散而急剧下降。相比之下，在初始速度较低的系统中，观测到星系间的合并现象，导致恒星形成率出现多重峰值。星系间较大的初始距离也与星系系统是否发生合并相关，因为这意味着引力作用的时间尺度更长，从而导致碰撞时刻的相对速度更高。此外，研究发现星系中的恒星形成率与初始气体含量存在明确关联。总体而言，我们的结果表明：相对撞击速度、星系初始间距以及气体含量是分析碰撞星系中恒星形成率的重要参数。