STScI Logo

Calibration Database System

The AGN Atlas

This atlas contains a few spectral templates of AGNs covering the ultraviolet to near-infrared spectral range (see Table 1 for spectral coverage). The LINER and Seyfert 2 templates have been obtained with the large aperture (10" by 20") and low resolution spectrographs of the IUE satellite. The optical spectra were obtained through a long slit with a 10" width, were a window of 20" long was extracted to mach the IUE aperture (Calzetti 1995, private comm.). The flux of the LINER and Seyfert2 templates is normalized to a Johnson visual magnitude of 12.5 (STMAG).

The Seyfert1 template consists of an UV spectrum obtained with the IUE low resolution spectrographs and of a ground-based optical spectrum. The bright QSO template is a composite spectrum from the Large Bright Quasar Survey of Francie and collaborators (1991). The Seyfert1 and QSO spectral templates are normalized to a Johnson blue magnitude of 12.5 (STMAG).

The NGC 1068 template is a composite spectrum. The continuum contains the nebular, stellar, and power-law contributions. The observed fluxes and FWHM of the UV, optical and near-IR emission lines are also incorporated into the template (J.R. Walsh, private comm; read also the header of the STSDAS binary for further details).

Details about how each template has been constructed can be found in the header of the STSDAS binary file, or in the references given above. The header can be read using the tupar task of the IRAF ttools package. STSDAS files can also be dumped into an ASCII formatted file using the tdump task of the IRAF ttools package.

     Table:   List of Templates in the AGN Atlas

  File Name             Spectral coverage              Comments

liner_template            1235  -  7550             spectrum of M81 
seyfert2_template         1235  -  9945             average of various spectra
seyfert1_template         1132  -  7078             spectrum of NGC 5548
qso_template               800  -  6000             average of various spectra
ngc1068_template          1000  - 11000             model: lines + cont.


  Francis et al. 1991, ApJ 373, 465.

To the AGN Atlas