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SIGNATURES OF RELATIVISTIC HELICAL MOTION IN THE ROTATION MEASURES OF ACTIVE GALACTIC NUCLEUS JETS

Abstract

Polarization has proven to be an invaluable tool for probing magnetic fields in relativistic jets. Maps of the intrinsic polarization vectors have provided the best evidence to date for uniform, toroidally dominated magnetic fields within jets. More recently, maps of the rotation measure (RM) in jets have for the first time probed the field geometry of the cool, moderately relativistic surrounding material. In most cases, clear signatures of the toroidal magnetic field are detected, corresponding to gradients in RM profiles transverse to the jet. However, in many objects, these profiles also display marked asymmetries that are difficult to explain in simple helical jet models. Furthermore, in some cases, the RM profiles are strongly frequency and/or time dependent. Here we show that these features may be naturally accounted for by including relativistic helical motion in the jet model. In particular, we are able to reproduce bent RM profiles observed in a variety of jets, frequency-dependent RM profile morphologies, and even the time dependence of the RM profiles of knots in 3C 273. Finally, we predict that some sources may show reversals in their RM profiles at sufficiently high frequencies, depending upon the ratio of the components of jet sheath velocity transverse  More>>
Authors:
Broderick, Avery E; [1]  Loeb, Abraham [2] 
  1. Canadian Institute for Theoretical Astrophysics, 60 St. George Street, Toronto, ON M5S 3H8 (Canada)
  2. Institute for Theory and Computation, Harvard University, Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States)
Publication Date:
Oct 01, 2009
Product Type:
Journal Article
Resource Relation:
Journal Name: Astrophysical Journal (Online); Journal Volume: 703; Journal Issue: 2; Other Information: DOI: 10.1088/0004-637X/703/2/L104
Subject:
71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; ASYMMETRY; FREQUENCY DEPENDENCE; GALAXIES; JETS; MAGNETIC FIELDS; MORPHOLOGY; POLARIZATION; RADIANT HEAT TRANSFER; RELATIVISTIC RANGE; ROTATION; TIME DEPENDENCE; ENERGY RANGE; ENERGY TRANSFER; HEAT TRANSFER; MOTION
OSTI ID:
21371921
Country of Origin:
United States
Language:
English
Other Identifying Numbers:
Journal ID: ISSN 1538-4357; TRN: US10P2721102375
Availability:
Available from http://dx.doi.org/10.1088/0004-637X/703/2/L104
Submitting Site:
INIS
Size:
page(s) L104-L108
Announcement Date:
Dec 30, 2010

Citation Formats

Broderick, Avery E, and Loeb, Abraham. SIGNATURES OF RELATIVISTIC HELICAL MOTION IN THE ROTATION MEASURES OF ACTIVE GALACTIC NUCLEUS JETS. United States: N. p., 2009. Web. doi:10.1088/0004-637X/703/2/L104.
Broderick, Avery E, & Loeb, Abraham. SIGNATURES OF RELATIVISTIC HELICAL MOTION IN THE ROTATION MEASURES OF ACTIVE GALACTIC NUCLEUS JETS. United States. doi:10.1088/0004-637X/703/2/L104.
Broderick, Avery E, and Loeb, Abraham. 2009. "SIGNATURES OF RELATIVISTIC HELICAL MOTION IN THE ROTATION MEASURES OF ACTIVE GALACTIC NUCLEUS JETS." United States. doi:10.1088/0004-637X/703/2/L104. https://www.osti.gov/servlets/purl/10.1088/0004-637X/703/2/L104.
@misc{etde_21371921,
title = {SIGNATURES OF RELATIVISTIC HELICAL MOTION IN THE ROTATION MEASURES OF ACTIVE GALACTIC NUCLEUS JETS}
author = {Broderick, Avery E, and Loeb, Abraham}
abstractNote = {Polarization has proven to be an invaluable tool for probing magnetic fields in relativistic jets. Maps of the intrinsic polarization vectors have provided the best evidence to date for uniform, toroidally dominated magnetic fields within jets. More recently, maps of the rotation measure (RM) in jets have for the first time probed the field geometry of the cool, moderately relativistic surrounding material. In most cases, clear signatures of the toroidal magnetic field are detected, corresponding to gradients in RM profiles transverse to the jet. However, in many objects, these profiles also display marked asymmetries that are difficult to explain in simple helical jet models. Furthermore, in some cases, the RM profiles are strongly frequency and/or time dependent. Here we show that these features may be naturally accounted for by including relativistic helical motion in the jet model. In particular, we are able to reproduce bent RM profiles observed in a variety of jets, frequency-dependent RM profile morphologies, and even the time dependence of the RM profiles of knots in 3C 273. Finally, we predict that some sources may show reversals in their RM profiles at sufficiently high frequencies, depending upon the ratio of the components of jet sheath velocity transverse and parallel to the jet. Thus, multi-frequency RM maps promise a novel way in which to probe the velocity structure of relativistic outflows.}
doi = {10.1088/0004-637X/703/2/L104}
journal = {Astrophysical Journal (Online)}
issue = {2}
volume = {703}
place = {United States}
year = {2009}
month = {Oct}
}