Infrared photometric study of SDSS selected narrow line Seyfert 1 galaxies

In addition, relations between infrared colors and related (to Hβ) strengths of some important lines are also investigated. The results show that the related strengths of [FeII] 4570 Å are positively correlated with infrared colors in the 1-5 µm region, but negatively correlated with infrared colors in the 12-22 µm region; the related strength of [OIII] 5007 Å are negatively correlated with infrared colors in the 1-5 µm region, but positively correlated with infrared colors in the 12-22 µm region; the related strength of [NII]6583 Å are also negatively correlated with infrared colors in the 1-5 µm region, but positively correlated with infrared colors in the 12-22 µm region. Therefore it is indicated that the behavior of [FeII] 4570 Å is just opposed to that for [OIII] 5007 Å and [NII] 6583 Å This result may be caused by different origins of such lines.