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Galaxy Zoo: ‘Hanny's Voorwerp’, a quasar light echo?

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Galaxy Zoo : ‘Hanny's Voorwerp’, a quasar light echo? / Lintott, Chris J.; Schawinski, Kevin; Keel, William; Van Arkel, Hanny; Bennert, Nicola; Edmondson, Edward; Thomas, Daniel; Smith, Daniel J. B.; Herbert, Peter D.; Jarvis, Matt J.; Virani, Shanil; Andreescu, Dan; Bamford, Steven P.; Land, Kate; Murray, Phil; Nichol, Robert C.; Raddick, M. Jordan; Slosar, Anze; Szalay, Alex; Vandenberg, Jan.

In: Monthly Notices of the Royal Astronomical Society, Vol. 399, No. 1, 11.10.2009, p. 129-140.

Research output: Contribution to journalArticle

Harvard

Lintott, CJ, Schawinski, K, Keel, W, Van Arkel, H, Bennert, N, Edmondson, E, Thomas, D, Smith, DJB, Herbert, PD, Jarvis, MJ, Virani, S, Andreescu, D, Bamford, SP, Land, K, Murray, P, Nichol, RC, Raddick, MJ, Slosar, A, Szalay, A & Vandenberg, J 2009, 'Galaxy Zoo: ‘Hanny's Voorwerp’, a quasar light echo?', Monthly Notices of the Royal Astronomical Society, vol. 399, no. 1, pp. 129-140. https://doi.org/10.1111/j.1365-2966.2009.15299.x

APA

Lintott, C. J., Schawinski, K., Keel, W., Van Arkel, H., Bennert, N., Edmondson, E., ... Vandenberg, J. (2009). Galaxy Zoo: ‘Hanny's Voorwerp’, a quasar light echo? Monthly Notices of the Royal Astronomical Society, 399(1), 129-140. https://doi.org/10.1111/j.1365-2966.2009.15299.x

Vancouver

Lintott CJ, Schawinski K, Keel W, Van Arkel H, Bennert N, Edmondson E et al. Galaxy Zoo: ‘Hanny's Voorwerp’, a quasar light echo? Monthly Notices of the Royal Astronomical Society. 2009 Oct 11;399(1):129-140. https://doi.org/10.1111/j.1365-2966.2009.15299.x

Author

Lintott, Chris J. ; Schawinski, Kevin ; Keel, William ; Van Arkel, Hanny ; Bennert, Nicola ; Edmondson, Edward ; Thomas, Daniel ; Smith, Daniel J. B. ; Herbert, Peter D. ; Jarvis, Matt J. ; Virani, Shanil ; Andreescu, Dan ; Bamford, Steven P. ; Land, Kate ; Murray, Phil ; Nichol, Robert C. ; Raddick, M. Jordan ; Slosar, Anze ; Szalay, Alex ; Vandenberg, Jan. / Galaxy Zoo : ‘Hanny's Voorwerp’, a quasar light echo?. In: Monthly Notices of the Royal Astronomical Society. 2009 ; Vol. 399, No. 1. pp. 129-140.

Bibtex

@article{3949185e522246aab9918b85844d6b48,
title = "Galaxy Zoo: ‘Hanny's Voorwerp’, a quasar light echo?",
abstract = "We report the discovery of an unusual object near the spiral galaxy IC 2497, discovered by visual inspection of the Sloan Digital Sky Survey (SDSS) as part of the Galaxy Zoo project. The object, known as Hanny's Voorwerp, is bright in the SDSS g band due to unusually strong [O iii]4959, 5007 emission lines. We present the results of the first targeted observations of the object in the optical, ultraviolet and X-ray, which show that the object contains highly ionized gas. Although the line ratios are similar to extended emission-line regions near luminous active galactic nucleus (AGN), the source of this ionization is not apparent. The emission-line properties, and lack of X-ray emission from IC 2497, suggest either a highly obscured AGN with a novel geometry arranged to allow photoionization of the object but not the galaxy's own circumnuclear gas, or, as we argue, the first detection of a quasar light echo. In this case, either the luminosity of the central source has decreased dramatically or else the obscuration in the system has increased within 105 yr. This object may thus represent the first direct probe of quasar history on these time-scales.",
author = "Lintott, {Chris J.} and Kevin Schawinski and William Keel and {Van Arkel}, Hanny and Nicola Bennert and Edward Edmondson and Daniel Thomas and Smith, {Daniel J. B.} and Herbert, {Peter D.} and Jarvis, {Matt J.} and Shanil Virani and Dan Andreescu and Bamford, {Steven P.} and Kate Land and Phil Murray and Nichol, {Robert C.} and Raddick, {M. Jordan} and Anze Slosar and Alex Szalay and Jan Vandenberg",
note = "Copyright 2009 The Authors. Journal compilation Copyright 2009 RAS",
year = "2009",
month = "10",
day = "11",
doi = "10.1111/j.1365-2966.2009.15299.x",
language = "English",
volume = "399",
pages = "129--140",
journal = "MNRAS",
issn = "0035-8711",
publisher = "Oxford University Press",
number = "1",

}

RIS

TY - JOUR

T1 - Galaxy Zoo

T2 - ‘Hanny's Voorwerp’, a quasar light echo?

AU - Lintott, Chris J.

AU - Schawinski, Kevin

AU - Keel, William

AU - Van Arkel, Hanny

AU - Bennert, Nicola

AU - Edmondson, Edward

AU - Thomas, Daniel

AU - Smith, Daniel J. B.

AU - Herbert, Peter D.

AU - Jarvis, Matt J.

AU - Virani, Shanil

AU - Andreescu, Dan

AU - Bamford, Steven P.

AU - Land, Kate

AU - Murray, Phil

AU - Nichol, Robert C.

AU - Raddick, M. Jordan

AU - Slosar, Anze

AU - Szalay, Alex

AU - Vandenberg, Jan

N1 - Copyright 2009 The Authors. Journal compilation Copyright 2009 RAS

PY - 2009/10/11

Y1 - 2009/10/11

N2 - We report the discovery of an unusual object near the spiral galaxy IC 2497, discovered by visual inspection of the Sloan Digital Sky Survey (SDSS) as part of the Galaxy Zoo project. The object, known as Hanny's Voorwerp, is bright in the SDSS g band due to unusually strong [O iii]4959, 5007 emission lines. We present the results of the first targeted observations of the object in the optical, ultraviolet and X-ray, which show that the object contains highly ionized gas. Although the line ratios are similar to extended emission-line regions near luminous active galactic nucleus (AGN), the source of this ionization is not apparent. The emission-line properties, and lack of X-ray emission from IC 2497, suggest either a highly obscured AGN with a novel geometry arranged to allow photoionization of the object but not the galaxy's own circumnuclear gas, or, as we argue, the first detection of a quasar light echo. In this case, either the luminosity of the central source has decreased dramatically or else the obscuration in the system has increased within 105 yr. This object may thus represent the first direct probe of quasar history on these time-scales.

AB - We report the discovery of an unusual object near the spiral galaxy IC 2497, discovered by visual inspection of the Sloan Digital Sky Survey (SDSS) as part of the Galaxy Zoo project. The object, known as Hanny's Voorwerp, is bright in the SDSS g band due to unusually strong [O iii]4959, 5007 emission lines. We present the results of the first targeted observations of the object in the optical, ultraviolet and X-ray, which show that the object contains highly ionized gas. Although the line ratios are similar to extended emission-line regions near luminous active galactic nucleus (AGN), the source of this ionization is not apparent. The emission-line properties, and lack of X-ray emission from IC 2497, suggest either a highly obscured AGN with a novel geometry arranged to allow photoionization of the object but not the galaxy's own circumnuclear gas, or, as we argue, the first detection of a quasar light echo. In this case, either the luminosity of the central source has decreased dramatically or else the obscuration in the system has increased within 105 yr. This object may thus represent the first direct probe of quasar history on these time-scales.

U2 - 10.1111/j.1365-2966.2009.15299.x

DO - 10.1111/j.1365-2966.2009.15299.x

M3 - Article

VL - 399

SP - 129

EP - 140

JO - MNRAS

JF - MNRAS

SN - 0035-8711

IS - 1

ER -

ID: 1652674