Properties of Broad Band Continuum of Narrow Line Seyfert 1 Galaxies

We have performed a statistical study of the properties of the broadband continuum of Narrow Line Seyfert 1 galaxies (NLS1s) by collecting ratio,infrared, optical and X-ray continuum data from various databases and comparedthe results with control samples of Broad Line Seyfert 1 galaxies (BLSls). We findthat the fraction (～ 6%) of Radio Loud (RL) NLSls is significantly less than thatof BLS1s (～ 13%), which is caused by the lack of radio-very-loud sources in theformer. The rarity of RL NLS1s, especially radio-very-loud ones, is consistent withthe scenario of small black hole and high accretion rate for NLSls. Six new radio loudNLSls are found and five RL NLS1 candidates are presented. In comparison withthe BLS1s, the NLS1s tend to have stronger far infrared emission, cooler infraredcolors and redder B- K color, which suggests that NLS1s are hosted by dust-richernuclei. The NLS1s also show steeper soft X-ray spectrum and large soft X-rayto optical flux ratio, while a significant fraction show fiat soft X-ray spectra. Atleast two factors can account for this, absorption and spectral variability. We alsoperform a correlation analysis between various broad band data. It is found thatmost correlations identified for NLS1s are also valid for radio quiet BLS1s: (1) theoptical colors are anti-correlated with X-ray spectral index; (2) higher optical, X-ray and NIR luminosity objects show bluer optical colors and red H - K color; (3)higher luminosity objects show warmer IRAS color; (4) the radio loudness correlateswith B - K and X-ray to optical flux ratio. Radio loud objects behave somewhatdifferently in a few correlations.

Properties of Broad Band Continuum of Narrow Line Seyfert 1 Galaxies

We have performed a statistical study of the properties of the broad band continuum of Narrow Line Seyfert 1 galaxies (NLSls) by collecting ratio, infrared, optical and X-ray continuum data from various databases and compared the results with control samples of Broad Line Seyfert 1 galaxies (BLSls). We find that the fraction (- 6%) of Radio Loud (RL) NLSls is significantly less than that of BLSls (- 13%), which is caused by the lack of radio-very-loud sources in the former. The rarity of RL NLSls, especially radio-very-loud ones, is consistent with the scenario of small black hole and high accretion rate for NLSls. Six new radio loud NLSls are found and five RL NLS1 candidates are presented. In comparison with the BLSls, the NLSls tend to have stronger far infrared emission, cooler infrared colors and redder B - K color, which suggests that NLSls are hosted by dust-richer nuclei. The NLSls also show steeper soft X-ray spectrum and large soft X-ray to optical flux ratio, while a significant fraction show flat soft X-ray spectra. At least two factors can account for this, absorption and spectral variability. We also perform a correlation analysis between various broad band data. It is found that most correlations identified for NLSls are also valid for radio quiet BLSls: (1) the optical colors are anti-correlated with X-ray spectral index; (2) higher optical, X-ray and NIR luminosity objects show bluer optical colors and red H - K color; (3) higher luminosity objects show warmer IRAS color; (4) the radio loudness correlates with B - K and X-ray to optical flux ratio. Radio loud objects behave somewhat differently in a few correlations.