SIMBAD references

2005ApJ...625..727P - Astrophys. J., 625, 727-740 (2005/June-1)

Intrinsic curvature in the X-ray spectra of BL Lacertae objects.

PERLMAN E.S., MADEJSKI G., GEORGANOPOULOS M., ANDERSSON K., DAUGHERTY T., KROLIK J.H., RECTOR T., STOCKE J.T., KORATKAR A., WAGNER S., ALLER M., ALLER H. and ALLEN M.G.

Abstract (from CDS):

We report results from XMM-Newton observations of 13 X-ray bright BL Lacertae objects, selected from the Einstein Slew Survey sample (SSS). The survey was designed to look for evidence of departures of the X-ray spectra from a simple power-law shape (i.e., curvature and/or line features) and to find objects worthy of deeper study. Our data are generally well fit by power-law models, with three cases having hard (Γ<2; dN/dE∝E–Γ) spectra that indicate synchrotron peaks at E≳5 keV. Previous data had suggested a presence of absorption features in the X-ray spectra of some BL Lac objects. In contrast, none of these spectra show convincing examples of line features in either absorption or emission, suggesting that such features are rare among BL Lac objects, or, more likely, are artifacts caused by instrumental effects. We find significant evidence for intrinsic curvature [steepening by dΓ/d(logE)=0.4±0.15] in 14 of the 17 X-ray spectra. This cannot be explained satisfactorily via excess absorption, since the curvature is essentially constant from 0.5-6 keV, an observation that is inconsistent with the modest amounts of absorption that would be required. We use the XMM-Newton Optical Monitor data with concurrent radio monitoring to derive broadband spectral energy distributions and peak frequency estimates. From these, we examine models of synchrotron emission and model the spectral curvature we see as the result of episodic particle acceleration.

Abstract Copyright:

Journal keyword(s): Galaxies: BL Lacertae Objects: General - Galaxies: BL Lacertae Objects: Individual: Alphanumeric: 1ES 0033+595 - Galaxies: BL Lacertae Objects: Individual: Alphanumeric: 1ES 0120+340 - Galaxies: BL Lacertae Objects: Individual: Alphanumeric: 1ES 0145+138 - Galaxies: BL Lacertae Objects: Individual: Alphanumeric: 1ES 0323+022 - Galaxies: BL Lacertae Objects: Individual: Alphanumeric: 1ES 0347-121 - Galaxies: BL Lacertae Objects: Individual: Alphanumeric: 1ES 0414+009 - Galaxies: BL Lacertae Objects: Individual: Alphanumeric: 1ES 0647+250 - Galaxies: BL Lacertae Objects: Individual: Alphanumeric: 1ES 1028+511 - Galaxies: BL Lacertae Objects: Individual: Alphanumeric: 1ES 1101-232 - Galaxies: BL Lacertae Objects: Individual: Alphanumeric: 1ES 1255+244 - Galaxies: BL Lacertae Objects: Individual: Alphanumeric: 1ES 1553+113 - Galaxies: BL Lacertae Objects: Individual: Alphanumeric: 1ES 1959+650 - Galaxies: BL Lacertae Objects: Individual: Name: Markarian 180 - Galaxies: Active - Radiation Mechanisms: Nonthermal - X-Rays: Galaxies

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2021.07.28-23:03:46

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