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Title: The softest Einstein AGN (active galactic nuclei)

Abstract

We have undertaken a coarse spectral study to find the softest sources detected with the Imaging Proportional Counter (IPC) on the Einstein Observatory. Of the nearly 7700 IPC sources, 226 have color ratios that make them candidate ultrasoft'' sources; of these, 83 have small enough errors that we can say with confidence that they have a spectral component similar to those of the white dwarfs Sirius and HZ 43, nearby stars such as {alpha} Cen and Procyon, and typical polar'' cataclysmic variables. By means of catalog searches and ground-based optical and radio observations we have thus far identified 96 of the 226 candidate soft sources; 37 of them are active galactic nuclei (AGN). In the more selective subset of 83 sources, 47 have been identified, 12 of them with AGN. The list of 47 identifications is given in Cordova et al. For one QSO in our sample, E0132.8--411, we are able to fit the pulse-height data to a power-law model and obtain a best fit for the energy spectral index of 2. 2{sub {minus}0.4}{sup +0.6}. For the remainder of the AGN in the higher confidence sample we are able to infer on the basis of their x-ray colors that theymore » have a similar spectral component. Two-thirds of the AGN are detected below 0.5 keV only, while the remainder evidence a flatter spectral component in addition to the ultra-soft component. 14 refs., 5 figs.« less

Authors:
; ; ;  [1];  [2];  [3]
  1. (Los Alamos National Lab., NM (USA)
  2. (USA)
  3. (UK). Mullard Space Science Lab.)
Publication Date:
Research Org.:
Los Alamos National Lab., NM (USA)
Sponsoring Org.:
DOE/DP; National Aeronautic and Space Administration (NASA)
OSTI Identifier:
5469894
Report Number(s):
LA-UR-89-863; CONF-891127-1
ON: DE89009389
DOE Contract Number:
W-7405-ENG-36
Resource Type:
Conference
Resource Relation:
Conference: Einstein to AXAF conference, Cambridge, MA (USA), Nov 1989
Country of Publication:
United States
Language:
English
Subject:
71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; GALAXY NUCLEI; DETECTION; COSMIC X-RAY SOURCES; PROPORTIONAL COUNTERS; QUASARS; SIGNAL-TO-NOISE RATIO; COSMIC RADIO SOURCES; COSMIC RAY SOURCES; MEASURING INSTRUMENTS; RADIATION DETECTORS; 640105* - Astrophysics & Cosmology- Galaxies; 640102 - Astrophysics & Cosmology- Stars & Quasi-Stellar, Radio & X-Ray Sources

Citation Formats

Cordova, F.A., Kartje, J., Mason, K.O., Mittaz, J.P.D., Chicago Univ., IL, and University Coll., London. The softest Einstein AGN (active galactic nuclei). United States: N. p., 1989. Web.
Cordova, F.A., Kartje, J., Mason, K.O., Mittaz, J.P.D., Chicago Univ., IL, & University Coll., London. The softest Einstein AGN (active galactic nuclei). United States.
Cordova, F.A., Kartje, J., Mason, K.O., Mittaz, J.P.D., Chicago Univ., IL, and University Coll., London. Sun . "The softest Einstein AGN (active galactic nuclei)". United States. doi:. https://www.osti.gov/servlets/purl/5469894.
@article{osti_5469894,
title = {The softest Einstein AGN (active galactic nuclei)},
author = {Cordova, F.A. and Kartje, J. and Mason, K.O. and Mittaz, J.P.D. and Chicago Univ., IL and University Coll., London},
abstractNote = {We have undertaken a coarse spectral study to find the softest sources detected with the Imaging Proportional Counter (IPC) on the Einstein Observatory. Of the nearly 7700 IPC sources, 226 have color ratios that make them candidate ultrasoft'' sources; of these, 83 have small enough errors that we can say with confidence that they have a spectral component similar to those of the white dwarfs Sirius and HZ 43, nearby stars such as {alpha} Cen and Procyon, and typical polar'' cataclysmic variables. By means of catalog searches and ground-based optical and radio observations we have thus far identified 96 of the 226 candidate soft sources; 37 of them are active galactic nuclei (AGN). In the more selective subset of 83 sources, 47 have been identified, 12 of them with AGN. The list of 47 identifications is given in Cordova et al. For one QSO in our sample, E0132.8--411, we are able to fit the pulse-height data to a power-law model and obtain a best fit for the energy spectral index of 2. 2{sub {minus}0.4}{sup +0.6}. For the remainder of the AGN in the higher confidence sample we are able to infer on the basis of their x-ray colors that they have a similar spectral component. Two-thirds of the AGN are detected below 0.5 keV only, while the remainder evidence a flatter spectral component in addition to the ultra-soft component. 14 refs., 5 figs.},
doi = {},
journal = {},
number = ,
volume = ,
place = {United States},
year = {Sun Jan 01 00:00:00 EST 1989},
month = {Sun Jan 01 00:00:00 EST 1989}
}

Conference:
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