WN 1626 + 5153: a giant radio galaxy from the WENSS survey

Röttgering, H. J. A.; Tang, Yimeng; Bremer, M.; Bruyn, A. G. de; Miley, G. K.; Rengelink, R.; Bremer, M.

doi:10.1093/mnras/282.3.1033

Cited by 10 publications

(8 citation statements)

References 2 publications

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“…The objects shown in Fig. 5 appear to be similar to the giant radio source WN 1626+5153 discovered in the Westerbork Northern Sky Survey (Röttgering et al 1996).…”

Section: Extended Sources In the Kr Cataloguesupporting

confidence: 60%

A sharper view of the outer Galaxy at 1420 and 408 MHz from the Canadian Galactic Plane Survey – I. Revisiting the KR catalogue and new Gigahertz Peaked Spectrum sources

Kerton

2006

Monthly Notices of the Royal Astronomical Society

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Arcminute-resolution radio continuum images at 408 and 1420 MHz from the Canadian Galactic Plane Survey (CGPS) have been used to re-examine radio sources listed in the Kallas & Reich catalogue. This catalogue is of particular interest to Galactic studies as it lists both extended and compact radio sources found in the second Galactic quadrant. We have determined the nature (extended versus compact, Galactic versus extragalactic) of all of these bright radio sources. A number of large H II regions with no optical counterparts are highlighted along with a sample of large radio galaxies. Many sources previously thought to be extended Galactic objects are shown to be point sources. A sample of point sources with flat or rising spectra between 408 and 1420 MHz has been compiled, and within this sample likely Gigahertz Peaked Spectrum sources have been identified.

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“…The objects shown in Fig. 5 appear to be similar to the giant radio source WN 1626+5153 discovered in the Westerbork Northern Sky Survey (Röttgering et al 1996).…”

Section: Extended Sources In the Kr Cataloguesupporting

confidence: 60%

A sharper view of the outer Galaxy at 1420 and 408 MHz from the Canadian Galactic Plane Survey – I. Revisiting the KR catalogue and new Gigahertz Peaked Spectrum sources

Kerton

2006

Monthly Notices of the Royal Astronomical Society

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“…These include NGC 5252 with its well-documented set of ionization cones (Prieto & Freudling 1996, Morse et al 1998, and the large-scale double radio source hosts NGC 5972 (Véron-Cetty & Véron 2001) and Mkn 1498 (Röttgering et al 1996). Additional objects, some showing larger and more luminous EELRs, were newly found in this survey.…”

Section: Galaxy Samplementioning

confidence: 71%

Fading AGN Candidates: AGN Histories and Outflow Signatures^∗

Keel

Lintott

Maksym

et al. 2017

ApJ

101

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We consider the energy budgets and radiative history of eight fading AGN, identified from an energy shortfall between the requirements to ionize very extended (radius > 10 kpc) ionized clouds and the luminosity of the nucleus as we view it directly. All show evidence of significant fading on ≈ 50, 000-year timescales. We explore the use of minimum ionizing luminosity Q ion derived from photoionization balance in the brightest pixels in Hα at each projected radius. Tests using presumably constant Palomar-Green (PG) QSOs, and one of our targets with detailed photoionization modeling, suggest that we can derive useful histories of individual AGN, with the caveat that the minimum ionizing luminosity is always an underestimate and subject to uncertainties about fine structure in the ionized material. These consistency tests suggest that the degree of underestimation from the upper envelope of reconstructed Q ion values is roughly constant for a given object and therefore does not prevent such derivation. The AGN in our sample show a range of behaviors, with rapid drops and standstills; the common feature is a rapid drop in the last ≈ 2 × 10 4 years before the direct view of the nucleus. The e-folding timescales for ionizing luminosity are mostly in the thousands of years, with a few episodes as short as 400 years. In the limit of largely obscured AGN, we find additional evidence for fading from the shortfall between even the lower limits from recombination balance and the maximum luminosities derived from from infrared fluxes. We compare these long-term light curves, and the occurrence of these fading objects among all optically identified AGN, to simulations of AGN accretion; the strongest variations on these timespans are seen in models with strong and local (parsec-scale) feedback. We present Gemini integral-field optical spectroscopy, which shows a very limited role for outflows in these ionized structures. While rings and loops of emission, morphologically suggestive of outflow, are common, their kinematic structure shows some to be in regular rotation. UGC 7342 exhibits local signatures of outflows < 300 km s −1 , largely associated with very diffuse emission, and possibly entraining gas in one of the clouds seen in HST images. Only in the Teacup AGN do we see outflow signatures of order 1000 km s −1 . In contrast to the extended emission regions around many radio-loud AGN, the clouds around these fading AGN consist largely of tidal debris being externally illuminated but not displaced by AGN outflows.

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“…This could be explained if the ionization cones have extremely broad opening angles, or if the radio structure makes a dramatic and yet‐unobserved twist on small scales. Similarly, Mrk 1498 is associated with a giant low‐frequency double radio source (Röttgering et al 1996), with projected separation 1.1 Mpc. In this case as well, the orientations of the emission‐line structures and the large radio source differ strongly, by about .…”

Section: Noteworthy Systemsmentioning

confidence: 99%

The Galaxy Zoo survey for giant AGN-ionized clouds: past and present black hole accretion events

Keel¹,

Chojnowski²,

Bennert³

et al. 2011

Monthly Notices of the Royal Astronomical Society

148

195

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Some active galactic nuclei (AGN) are surrounded by extended emission‐line regions (EELRs), which trace both the illumination pattern of escaping radiation and its history over the light travel time from the AGN to the gas. From a new set of such EELRs, we present evidence that the AGN in many Seyfert galaxies undergo luminous episodes 0.2–2 years in duration. Motivated by the discovery of the spectacular nebula known as Hanny’s Voorwerp, ionized by a powerful AGN which has apparently faded dramatically within years, Galaxy Zoo volunteers have carried out both targeted and serendipitous searches for similar emission‐line clouds around low‐redshift galaxies. We present the resulting list of candidates and describe spectroscopy identifying 19 galaxies with AGN‐ionized regions at projected radii kpc. This search recovered known EELRs (such as Mrk 78, Mrk 266 and NGC 5252) and identified additional previously unknown cases, one with detected emission to kpc. One new Sy 2 was identified. At least 14/19 are in interacting or merging systems, suggesting that tidal tails are a prime source of distant gas out of the galaxy plane to be ionized by an AGN. We see a mix of one‐ and two‐sided structures, with observed cone angles from 23 to 112. We consider the energy balance in the ionized clouds, with lower and upper bounds on ionizing luminosity from recombination and ionization‐parameter arguments, and estimate the luminosity of the core from the far‐infrared data. The implied ratio of ionizing radiation seen by the clouds to that emitted by the nucleus, on the assumption of a non‐variable nuclear source, ranges from 0.02 to ; 7/19 exceed unity. Small values fit well with a heavily obscured AGN in which only a small fraction of the ionizing output escapes to be traced by surrounding gas. However, large values may require that the AGN has faded over tens of thousands of years, giving us several examples of systems in which such dramatic long‐period variation has occurred; this is the only current technique for addressing these time‐scales in AGN history. The relative numbers of faded and non‐faded objects we infer, and the projected extents of the ionized regions, give our estimate (0.2–2 years) for the length of individual bright phases.

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WN 1626 + 5153: a giant radio galaxy from the WENSS survey

Cited by 10 publications

References 2 publications

A sharper view of the outer Galaxy at 1420 and 408 MHz from the Canadian Galactic Plane Survey – I. Revisiting the KR catalogue and new Gigahertz Peaked Spectrum sources

A sharper view of the outer Galaxy at 1420 and 408 MHz from the Canadian Galactic Plane Survey – I. Revisiting the KR catalogue and new Gigahertz Peaked Spectrum sources

Fading AGN Candidates: AGN Histories and Outflow Signatures^∗

The Galaxy Zoo survey for giant AGN-ionized clouds: past and present black hole accretion events

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WN 1626 + 5153: a giant radio galaxy from the WENSS survey

Cited by 10 publications

References 2 publications

A sharper view of the outer Galaxy at 1420 and 408 MHz from the Canadian Galactic Plane Survey – I. Revisiting the KR catalogue and new Gigahertz Peaked Spectrum sources

A sharper view of the outer Galaxy at 1420 and 408 MHz from the Canadian Galactic Plane Survey – I. Revisiting the KR catalogue and new Gigahertz Peaked Spectrum sources

Fading AGN Candidates: AGN Histories and Outflow Signatures∗

The Galaxy Zoo survey for giant AGN-ionized clouds: past and present black hole accretion events

Contact Info

Product

Resources

About

Fading AGN Candidates: AGN Histories and Outflow Signatures^∗