J/ApJS/141/31 JHK' imaging photometry of Seyfert 1. II. (Enya+, 2002) ================================================================================ JHK' imaging photometry of Seyfert 1 active galactic nuclei and quasars. II. Observation of long-term variability. Enya K., Yoshii Y., Kobayashi Y., Minezaki T., Suganuma M., Tomita H., Peterson B.A. =2002ApJS..141...31E ================================================================================ ADC_Keywords: Active gal. nuclei ; QSOs ; Photometry, infrared Keywords: galaxies: active - galaxies: photometry - galaxies: Seyfert - infrared: galaxies - quasars: general Abstract: Observations of 226 AGNs in the near-infrared J, H, and K' bands are presented along with the analysis of the observations for variability. Our sample consists mainly of Seyfert 1 AGNs and QSOs. About a quarter of the objects in each category are radio loud. The AGNs in the entire sample have the redshifts spanning the range from z=0 to 1, and the absolute magnitudes from M_B_=-29 to -18. All the objects were observed twice, and their variability was measured by differential photometry. A reduction method of differential photometry, optimized to the analysis of extended images, has been developed. The systematic error in variability arising from AGNs of highly extended images is estimated to be less than 0.01mag in each of the J, H, and K' bands. The systematic error arising from the flat-fielding is negligible for most AGNs, although it is more than 0.1mag for some particular cases. The overall average flat-fielding error is 0.03mag for the image pairs. We find that these systematic errors are superseded by statistical errors, and the overall average total systematic and statistical errors amounts to 0.05mag in the measured variability in each band. File Summary: -------------------------------------------------------------------------------- FileName Lrecl Records Explanations -------------------------------------------------------------------------------- ReadMe 80 . This file table1.dat 90 212 Variability data of 226 AGNs -------------------------------------------------------------------------------- See also: VII/224 : Quasars and Active Galactic Nuclei (10th Ed.) (Veron+ 2001) J/ApJS/141/23 : JHK' imaging photometry of Seyfert 1. I. (Enya+, 2002) Byte-by-byte Description of file: table1.dat -------------------------------------------------------------------------------- Bytes Format Units Label Explanations -------------------------------------------------------------------------------- 1- 3 I3 --- Num Target AGN number 5- 19 A15 --- Name AGN name 21- 26 F6.3 mag dJmag ? J band differential photometry variability 28- 32 F5.3 mag e_dJmag ? The error in dJmag 34- 35 I2 --- o_dJmag ? Number of reference objects used in dJmag 37- 42 F6.3 mag dHmag ? H band differential photometry variability 44- 48 F5.3 mag e_dHmag ? The error in dHmag 50- 51 I2 --- o_dHmag ? Number of reference objects used in dHmag 53- 58 F6.3 mag dK'mag ? K' band differential photometry variability 60- 64 F5.3 mag e_dK'mag ? The error in dK'mag 66- 67 I2 --- o_dK'mag ? Number of reference objects used in dK'mag 69- 78 A10 "YYYY/MM/DD" Obs1 Date of first observation 80- 89 A10 "YYYY/MM/DD" Obs2 Date of second observation -------------------------------------------------------------------------------- History: From electronic version of the journal ================================================================================ (End) Greg Schwarz [AAS], Patricia Bauer [CDS] 09-Jul-2002