THE STUDY OF AGN FROM UV to X-RAYS
Paul Green (PI), Joanna Kuraszkiewicz, & Karl Forster


Project Papers:

"Emission Line Properties of AGN from a post-COSTAR FOS HST Spectral Atlas"
Joanna Kuraszkiewicz, Paul J. Green, D. Michael Crenshaw, Jay Dunn, Karl Forster, Marianne Vestergaard, & Thomas L. Aldcroft, 2004, ApJS, 150, 165 [21pp]

Spectral modeling PLOTS
Emission line measurements: -FORMAT, and DATA
We make our digital post-COSTAR merged/calibrated spectra available as tarred, gzipped ASCII spectra.
(Columns are Wavelength (AA), flux and error (ergs/cm^2/sec/AA). Please cite us!)

"Evidence for a Strong NV/CIV Correlation Between Emission and Absorption Lines in AGN"
Joanna Kuraszkiewicz & Paul J. Green 2003, ApJ Letters, 581, L77 [6pp]
SUPPLEMENTAL TABLES (available here only):
Absorption line measurements for the program and control samples.
Emission line measurements for the program and control samples.

"Emission Line Properties of AGN from a pre-COSTAR FOS HST Spectral Atlas"
Joanna Kuraszkiewicz, Paul J. Green, Karl Forster, Thomas L. Aldcroft, Ian Evans, & Anuradha Koratkar 2002, ApJS, 143, 257 [49pp]

Spectral modeling PLOTS
Emission line measurements: -FORMAT, and DATA
Digital pre-COSTAR merged/calibrated spectra available from Evans, I.N. & Koratkar, A.P. 2004, ApJS, 150, 73, as
(STScI FITS format) or from us as tarred, gzipped ASCII spectra.
(Columns are Wavelength (AA), flux and error (ergs/cm^2/sec/AA). Please cite us!)

"Quasar Evolution and the Baldwin Effect in the Large Bright Quasar Survey"
Paul J. Green, Karl Forster, and Joanna Kuraszkiewicz 2001 ApJ, 556, 727 [16pp]

"Emission Line Properties of the Large Bright Quasar Survey"
Karl Forster, Paul J. Green, Thomas L. Aldcroft, Marianne Vestergaard, Craig B. Foltz, & Paul C. Hewett 2001, ApJS, 134, 35
Spectral modeling PLOTS
Emission line measurements: FORMAT, and DATA
Continuum measurements: FORMAT, and DATA

The Hubble/ROSAT Continuum and Ultraviolet Line Emission Study (H/RCULES) of AGN enables characterization of:


Spectral energy distributions from X-ray to Radio.
The `Big Blue Bump'.
The luminosity dependence of the SED.
The relationship between radio loudness and UV -- X-ray characteristics in AGN.
Emission line properties.
The Baldwin effect and its relation to the SED.
The primary source of variation in UV spectral properties of AGN (Boroson & Green 1992 primary eigenvector).
The link between the X-ray soft excess and the appearance of iron emission lines and coronal lines.
Comparison between UV and X-ray absorption.
The frequency of occurrence of UV absorption.
The relationship to X-ray absorption (warm absorbers).
Is there a luminosity dependence of absorption?

Prior to the expected completion of the HST FOS atlas of AGN spectra, we have been analyzing spectra of the LBQS sample (956 QSOs), now nearly complete. ROSAT X-ray fluxes or upper limits exist for 90% of the sample. Here are some example fits showing the characteristic resolution, S/N and fit quality of these spectra:

2244+0020
2247+0135
2248+0127

We tackle the challenge of analyzing such a large sample of AGN spectra using software developed for the Chandra X-ray telescope, a NASA Great Observatory. We use the Sherpa fitting and plotting environment within the CIAO analysis package. This also allows not only multi-component user models for spectral fitting, but also analysis of the combined X-ray - UV - optical SEDs. Absorption lines in the UV spectra are identified and measured using FINDSL (Aldcroft 1995) and the iron emission features are fitted using a template generated from the UV spectrum of IZw1 (Vestergaard & Wilkes 1999). A detailed explanation of our techniques are presented in a (large postscript) poster by Forster et al. (1999) from the 1999 AAS HEAD meeting.

The FOS observations currently consist of pre-COSTAR spectra. The pre-COSTAR spectra will appear in a complete atlas of recalibrated HST FOS spectra of AGN (Evans, Koratkar, & Pesto in prep), and contains proportions of radio-loud (76%) and radio-quiet (24%) objects similar to the full FOS sample. ROSAT PSPC observations are available for approximately half of this sub-sample.



Back to Paul Green's HomePage .
My email address is pgreen AT cfa. harvard. edu
Phone is (617)495-7057 and FAX (617)495-7356, at the
Center for Astrophysics,
60 Garden St., Cambridge MA 02138