Research output: Contribution to journal › Article › peer-review
Multiepoch very long baseline array observations of egret-detected quasars and BL Lacertae objects : Connection between superluminal ejections and gamma-ray flares in blazars. / Jorstad, Svetlana G.; Marscher, Alan P.; Mattox, John R.; Aller, Margo F.; Aller, Hugh D.; Wehrle, Ann E.; Bloom, Steven D.
In: Astrophysical Journal, Vol. 556, No. 2 PART 1, 01.08.2001, p. 738-748.Research output: Contribution to journal › Article › peer-review
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TY - JOUR
T1 - Multiepoch very long baseline array observations of egret-detected quasars and BL Lacertae objects
T2 - Connection between superluminal ejections and gamma-ray flares in blazars
AU - Jorstad, Svetlana G.
AU - Marscher, Alan P.
AU - Mattox, John R.
AU - Aller, Margo F.
AU - Aller, Hugh D.
AU - Wehrle, Ann E.
AU - Bloom, Steven D.
PY - 2001/8/1
Y1 - 2001/8/1
N2 - We examine the coincidence of times of high y-ray flux and ejections of superluminal components from the core in EGRET blazars based on a Very Long Baseline Array (VLBA) monitoring program at 22 and 43 GHz from 1993 November to 1997 July. In 23 cases of γ-ray flares for which sufficient VLBA data exist, 10 of the flares (in eight objects) fall within 1 σ uncertainties of the extrapolated epoch of zero separation from the core of a superluminal radio component. In each of two sources (0528 + 134 and 1730-130), two successive γ-ray flares were followed by the appearance of new superluminal components. We carried out statistical simulations that show that if the number of coincidences is ≥ 10, the radio and γ-ray events are associated with each other at greater than 99.999% confidence. Our analysis of the observed behavior, including variability of the polarized radio flux, of the sources before, during, and after the γ-ray flares suggests that the γ-ray events occur in the superluminal radio knots. This implies that the γ-ray flares are caused by inverse Compton scattering by relativistic electrons in the parsec-scale regions of the jet rather than closer to the central engine.
AB - We examine the coincidence of times of high y-ray flux and ejections of superluminal components from the core in EGRET blazars based on a Very Long Baseline Array (VLBA) monitoring program at 22 and 43 GHz from 1993 November to 1997 July. In 23 cases of γ-ray flares for which sufficient VLBA data exist, 10 of the flares (in eight objects) fall within 1 σ uncertainties of the extrapolated epoch of zero separation from the core of a superluminal radio component. In each of two sources (0528 + 134 and 1730-130), two successive γ-ray flares were followed by the appearance of new superluminal components. We carried out statistical simulations that show that if the number of coincidences is ≥ 10, the radio and γ-ray events are associated with each other at greater than 99.999% confidence. Our analysis of the observed behavior, including variability of the polarized radio flux, of the sources before, during, and after the γ-ray flares suggests that the γ-ray events occur in the superluminal radio knots. This implies that the γ-ray flares are caused by inverse Compton scattering by relativistic electrons in the parsec-scale regions of the jet rather than closer to the central engine.
KW - BL Lacertae objects: general
KW - Galaxies: jets
KW - Gamma rays: observations
KW - Quasars: general
KW - Radio continuum: galaxies
UR - http://www.scopus.com/inward/record.url?scp=0035429707&partnerID=8YFLogxK
U2 - 10.1086/321605
DO - 10.1086/321605
M3 - Article
AN - SCOPUS:0035429707
VL - 556
SP - 738
EP - 748
JO - Astrophysical Journal
JF - Astrophysical Journal
SN - 0004-637X
IS - 2 PART 1
ER -
ID: 88371158