The Peculiar Light Curve of J1415+1320: A Case Study in Extreme Scattering Events

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The Peculiar Light Curve of J1415+1320 : A Case Study in Extreme Scattering Events. / Vedantham, H. K.; Readhead, A.C.S.; Hovatta, T.; Koopmans, L. V.E.; Pearson, T. J.; Blandford, R. D.; Gurwell, M. A.; Lähteenmäki, A.; Max-Moerbeck, W.; Pavlidou, V.; Ravi, V.; Reeves, Rodrigo A.; Richards, J. L.; Tornikoski, M.; Zensus, J. A.

In: Astrophysical Journal, Vol. 845, No. 2, 90, 20.08.2017.

Research output: Contribution to journalArticleScientificpeer-review

Harvard

Vedantham, HK, Readhead, ACS, Hovatta, T, Koopmans, LVE, Pearson, TJ, Blandford, RD, Gurwell, MA, Lähteenmäki, A, Max-Moerbeck, W, Pavlidou, V, Ravi, V, Reeves, RA, Richards, JL, Tornikoski, M & Zensus, JA 2017, 'The Peculiar Light Curve of J1415+1320: A Case Study in Extreme Scattering Events' Astrophysical Journal, vol. 845, no. 2, 90. https://doi.org/10.3847/1538-4357/aa7741

APA

Vedantham, H. K., Readhead, A. C. S., Hovatta, T., Koopmans, L. V. E., Pearson, T. J., Blandford, R. D., ... Zensus, J. A. (2017). The Peculiar Light Curve of J1415+1320: A Case Study in Extreme Scattering Events. Astrophysical Journal, 845(2), [90]. https://doi.org/10.3847/1538-4357/aa7741

Vancouver

Vedantham HK, Readhead ACS, Hovatta T, Koopmans LVE, Pearson TJ, Blandford RD et al. The Peculiar Light Curve of J1415+1320: A Case Study in Extreme Scattering Events. Astrophysical Journal. 2017 Aug 20;845(2). 90. https://doi.org/10.3847/1538-4357/aa7741

Author

Vedantham, H. K. ; Readhead, A.C.S. ; Hovatta, T. ; Koopmans, L. V.E. ; Pearson, T. J. ; Blandford, R. D. ; Gurwell, M. A. ; Lähteenmäki, A. ; Max-Moerbeck, W. ; Pavlidou, V. ; Ravi, V. ; Reeves, Rodrigo A. ; Richards, J. L. ; Tornikoski, M. ; Zensus, J. A. / The Peculiar Light Curve of J1415+1320 : A Case Study in Extreme Scattering Events. In: Astrophysical Journal. 2017 ; Vol. 845, No. 2.

Bibtex - Download

@article{8f31e70785454f22acb7f1ac65449d44,
title = "The Peculiar Light Curve of J1415+1320: A Case Study in Extreme Scattering Events",
abstract = "The radio light curve of J1415+1320 (PKS 1413+135) shows time-symmetric and recurring U-shaped features across the centimeter-wave and millimeter-wave bands. The symmetry of these features points to lensing by an intervening object as the cause. U-shaped events in radio light curves in the centimeter-wave band have previously been attributed to Extreme scattering events (ESE). ESEs are thought to be the result of lensing by compact plasma structures in the Galactic interstellar medium, but the precise nature of these plasma structures remains unknown. Since the strength of a plasma lens evolves with wavelength λ as , the presence of correlated variations at over a wide wavelength range casts doubt on the canonical ESE interpretation for J1415+1320. In this paper, we critically examine the evidence for plasma lensing in J1415+1320. We compute limits on the lensing strength and the associated free-free opacity of the putative plasma lenses. We compare the observed and model ESE light curves, and also derive a lower limit on the lens distance based on the effects of parallax due to the Earth's orbit around the Sun. We conclude that plasma lensing is not a viable interpretation for J1415+1320's light curves and that symmetric U-shaped features in the radio light curves of extragalactic sources do not present prima facie evidence for ESEs. The methodology presented here is generic enough to be applicable to any plasma-lensing candidate.",
keywords = "BL Lacertae objects: individual (PKS 1413+135), galaxies: jets, ISM: structure, scattering",
author = "Vedantham, {H. K.} and A.C.S. Readhead and T. Hovatta and Koopmans, {L. V.E.} and Pearson, {T. J.} and Blandford, {R. D.} and Gurwell, {M. A.} and A. L{\"a}hteenm{\"a}ki and W. Max-Moerbeck and V. Pavlidou and V. Ravi and Reeves, {Rodrigo A.} and Richards, {J. L.} and M. Tornikoski and Zensus, {J. A.}",
year = "2017",
month = "8",
day = "20",
doi = "10.3847/1538-4357/aa7741",
language = "English",
volume = "845",
journal = "Astrophysical Journal",
issn = "0004-637X",
number = "2",

}

RIS - Download

TY - JOUR

T1 - The Peculiar Light Curve of J1415+1320

T2 - A Case Study in Extreme Scattering Events

AU - Vedantham, H. K.

AU - Readhead, A.C.S.

AU - Hovatta, T.

AU - Koopmans, L. V.E.

AU - Pearson, T. J.

AU - Blandford, R. D.

AU - Gurwell, M. A.

AU - Lähteenmäki, A.

AU - Max-Moerbeck, W.

AU - Pavlidou, V.

AU - Ravi, V.

AU - Reeves, Rodrigo A.

AU - Richards, J. L.

AU - Tornikoski, M.

AU - Zensus, J. A.

PY - 2017/8/20

Y1 - 2017/8/20

N2 - The radio light curve of J1415+1320 (PKS 1413+135) shows time-symmetric and recurring U-shaped features across the centimeter-wave and millimeter-wave bands. The symmetry of these features points to lensing by an intervening object as the cause. U-shaped events in radio light curves in the centimeter-wave band have previously been attributed to Extreme scattering events (ESE). ESEs are thought to be the result of lensing by compact plasma structures in the Galactic interstellar medium, but the precise nature of these plasma structures remains unknown. Since the strength of a plasma lens evolves with wavelength λ as , the presence of correlated variations at over a wide wavelength range casts doubt on the canonical ESE interpretation for J1415+1320. In this paper, we critically examine the evidence for plasma lensing in J1415+1320. We compute limits on the lensing strength and the associated free-free opacity of the putative plasma lenses. We compare the observed and model ESE light curves, and also derive a lower limit on the lens distance based on the effects of parallax due to the Earth's orbit around the Sun. We conclude that plasma lensing is not a viable interpretation for J1415+1320's light curves and that symmetric U-shaped features in the radio light curves of extragalactic sources do not present prima facie evidence for ESEs. The methodology presented here is generic enough to be applicable to any plasma-lensing candidate.

AB - The radio light curve of J1415+1320 (PKS 1413+135) shows time-symmetric and recurring U-shaped features across the centimeter-wave and millimeter-wave bands. The symmetry of these features points to lensing by an intervening object as the cause. U-shaped events in radio light curves in the centimeter-wave band have previously been attributed to Extreme scattering events (ESE). ESEs are thought to be the result of lensing by compact plasma structures in the Galactic interstellar medium, but the precise nature of these plasma structures remains unknown. Since the strength of a plasma lens evolves with wavelength λ as , the presence of correlated variations at over a wide wavelength range casts doubt on the canonical ESE interpretation for J1415+1320. In this paper, we critically examine the evidence for plasma lensing in J1415+1320. We compute limits on the lensing strength and the associated free-free opacity of the putative plasma lenses. We compare the observed and model ESE light curves, and also derive a lower limit on the lens distance based on the effects of parallax due to the Earth's orbit around the Sun. We conclude that plasma lensing is not a viable interpretation for J1415+1320's light curves and that symmetric U-shaped features in the radio light curves of extragalactic sources do not present prima facie evidence for ESEs. The methodology presented here is generic enough to be applicable to any plasma-lensing candidate.

KW - BL Lacertae objects: individual (PKS 1413+135)

KW - galaxies: jets

KW - ISM: structure

KW - scattering

UR - http://www.scopus.com/inward/record.url?scp=85028706709&partnerID=8YFLogxK

U2 - 10.3847/1538-4357/aa7741

DO - 10.3847/1538-4357/aa7741

M3 - Article

VL - 845

JO - Astrophysical Journal

JF - Astrophysical Journal

SN - 0004-637X

IS - 2

M1 - 90

ER -

ID: 15306656