SIMBAD references

In this work, we analyze the spectra of quasar J125216.58+052737.7 (z_em= 1.9035) which was observed by SDSS-I/II on 2003 January 30 and by BOSS on 2011 April 2. Both the continuum and the absorption spectra of this quasar show obvious variations between the two epochs. In the SDSS-I/II spectrum, we detect 8 C_IV λλ 1548, 1551 absorption systems, which are detected at z_abs= 1.9098, 1.8948, 1.8841, 1.8770, 1.8732, 1.8635, 1.8154, and 1.7359, respectively, and one Mg_IIλλ2796, 2803 absorption system at z_abs= 0.9912. Among these absorption systems, two C_IVλλ1548, 1551 absorption systems at z_abs= 1.9098 and 1.7359 and the Mg_IIλλ2796, 2803 absorption system are imprinted on the BOSS spectrum as well, and have similar absorption strengths when compared to those measured from the SDSS-I/II spectrum. Three C_IVλλ1548, 1551 absorption systems at z_abs= 1.8948, 1.8841, and 1.8770 are also detected in the BOSS spectrum, while their absorption strengths are much weaker than those measured from the SDSS-I/II spectrum; three systems at z_abs= 1.8732, 1.8635, and 1.8154 disappeared from the BOSS spectrum. Based on the variability analysis, the absorption systems that disappeared and weakened are likely to be intrinsic to the quasar. If these intrinsic absorption gases are blown away from the central region of the quasar, with respect to the quasar system, the absorption systems that disappeared would have separation velocities of 3147 km/s, 4161 km/s, and 9241 km/s, while the absorption systems that weakened would have separation velocities of 900 km/s, 2011 km/s, and 2751 km/s. Well-coordinated variations of the six _IV λλ 1548, 1551