Wide-field LOFAR imaging of the field around the double-double radio galaxy B1834+620

Orrù, E.; Velzen, S. van; Pizzo, R.; Yatawatta, S.; Paladino, R.; Iacobelli, M.; Murgia, M.; Falcke, H.; Morganti, Raffaella; Bruyn, A. G. de; Ferrari, C.; Anderson, J. M.; Bonafede, A.; Mulcahy, D. D.; Asgekar, A.; Avruch, I. M.; Beck, Rainer; Bell, M. E.; Bemmel, Ilse van; Bentum, Mark J.; Bernardi, G.; Best, P. N.; Breitling, F.; Broderick, J. W.; Brüggen, M.; Butcher, H. R.; Ciardi, B.; Conway, J.; Corstanje, A.; Geus, E. de; Deller, Adam T.; Duscha, S.; Eislöffel, J.; Engels, D.; Frieswijk, W.; Garrett, M. A.; Grießmeier, J.-M.; Gunst, A. W.; Hamaker, J. P.; Heald, G.; Hoeft, M.; Horst, A. J. van der; Intema, H. T.; Juette, E.; Köhler, Jana; Kondratiev, V. I.; Kuniyoshi, M.; Küper, G.; Loose, M.; Maat, P.; Mann, G.; Markoff, Sera; McFadden, R.; McKay-Bukowski, D.; Miley, G. K.; Moldón, J.; Molenaar, Gijs; Munk, H.; Nelles, A.; Paas, H.; Pandey-Pommier, M.; Pandey, V. N.; Pietka, G.; Polatidis, A. G.; Reich, W.; Röttgering, H. J. A.; Rowlinson, A.; Scaife, Anna M. M.; Schoenmakers, A. P.; Schwarz, Dominik J.; Serylak, M.; Shulevski, A.; Smirnov, O.; Steinmetz, Matthias; Stewart, A.; Swinbank, J.; Tagger, M.; Tasse, C.; Thoudam, Satyendra; Toribio, M. C.; Vermeulen, R. C.; Vocks, C.; Weeren, R. J. van; Wijers, R. A. M. J.; Wise, Michael; Wucknitz, O.

doi:10.1051/0004-6361/201526501

Cited by 35 publications

(26 citation statements)

References 52 publications

(81 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…O' Dea et al (2001) have classified 3C 236 as a doubledouble (Saikia & Jamrozy 2009;Orrù et al 2015) radio galaxy, since the restarted activity in the core has extended emission aligned with the large-scale lobes. Then, 3C 236 may be a "triple-double" radio galaxy; the inner hotspot in the NW lobe signifying a stall in the jet, or a short sputter in the accretion episode responsible for the creation of the large-scale lobes.…”

Section: Discussionmentioning

confidence: 99%

See 1 more Smart Citation

First look at the giant radio galaxy 3C 236 with LOFAR

Shulevski

Barthel

Morganti

et al. 2019

A&A

Self Cite

View full text Add to dashboard Cite

We have examined the giant radio galaxy 3C 236 using LOFAR at 143 MHz down to an angular resolution of 7 , in combination with observations at higher frequencies. We have used the low frequency data to derive spectral index maps with the highest resolution yet at these low frequencies. We confirm a previous detection of an inner hotspot in the north-west lobe and for the first time observe that the south-east lobe hotspot is in fact a triple hotspot, which may point to an intermittent source activity. Also, the spectral index map of 3C 236 shows that the spectral steepening at the inner region of the northern lobe is prominent at low frequencies. The outer regions of both lobes show spectral flattening, in contrast with previous high frequency studies. We derive spectral age estimates for the lobes, as well as particle densities of the IGM at various locations. We propose that the morphological differences between the lobes are driven by variations in the ambient medium density as well as the source activity history. 1 We assume a flat ΛCDM cosmology with H 0 = 67.8 km s −1 Mpc −1 and Ω m = 0.308, taken from the cosmological results of the full-mission Planck observations (Planck Collaboration XIII), and use the cosmol-Article number, page 1 of 10

show abstract

Section: Discussionmentioning

confidence: 99%

“…Also, Cantwell et al (submitted) studied NGC 6251 and found ages raging from 50 Myr to greater than 200 Myr. Orrù et al (2015) have studied the famous doubledouble GRG B1864+620 and showed that the source ages derived for its outer pair of radio lobes indicate that the AGN activity has stopped in the recent past.…”

Section: Introductionmentioning

confidence: 99%

First look at the giant radio galaxy 3C 236 with LOFAR

Shulevski

Barthel

Morganti

et al. 2019

A&A

Self Cite

View full text Add to dashboard Cite

show abstract

“…For a few double-double radio sources, spectral ageing modelling, based on equipartition assumptions, has provided estimates of the duration of the quiescent phase, which is found to be in the range 0.1∼10 Myr. This is usually at least a factor two shorter than the first active phase, which is observed to be of the order of a few tens up to a few hundreds of million years (Konar et al 2012Orrù et al 2015;Nandi et al 2019).…”

Section: Introductionmentioning

confidence: 99%

“…Major steps forward in the selection and study of restarted radio galaxies have recently been allowed by the advent of the LOw Frequency ARray (LOFAR,van Haarlem et al 2013) through its unprecedented sensitivity and resolution at low frequency, where the remnant lobes are expected to be brighter (see e.g. Shulevski et al 2015;Orrù et al 2015;Brienza et al 2018;Mahatma et al 2019;Jurlin et al 2020;Shabala et al 2020) However, there is one peculiar class of restarted radio galaxies that we may still be missing:. sources showing the footprint of their multi-epoch activity through spatial variations of their spectral index across their radio lobes.…”

Section: Introductionmentioning

confidence: 99%

Radio spectral properties and jet duty cycle in the restarted radio galaxy 3C388

Brienza

Morganti

Harwood

et al. 2020

A&A

Self Cite

View full text Add to dashboard Cite

Context. Restarted radio galaxies represent a unique tool for investigating the duty cycle of the jet activity in active galactic nuclei (AGN). The radio galaxy 3C388 has long been claimed to be a peculiar example of an AGN with multi-epoch activity because it shows a very sharp discontinuity in the GHz spectral index distribution of its lobes. Aims. We present here for the first time a spatially resolved study of the radio spectrum of 3C388 down to MHz frequencies aimed at investigating the radiative age of the source and constraining its duty cycle. Methods. We used new low-frequency observations at 144 MHz performed with the Low Frequency Array and at 350 MHz performed with the Very Large Array that we combined with archival data at higher frequencies (614, 1400, and 4850 MHz).Results. We find that the spectral indices in the lower frequency range, 144-614 MHz, have flatter values (α low ∼0.55-1.14) than those observed in the higher frequency range, 1400-4850 MHz, (α high ∼0.75-1.57), but they follow the same distribution across the lobes, with a systematic steepening towards the edges. However, the spectral shape throughout the source is not uniform and often deviates from standard models. This suggests that mixing of different particle populations occurs, although it remains difficult to understand whether this is caused by observational limitations (insufficient spatial resolution and/or projection effects) or by the intrinsic presence of multiple particle populations, which might be related to the two different outbursts.Conclusions. Using single-injection radiative models, we compute that the total source age is 80 Myr and that the duty cycle is about t on /t tot ∼ 60%, which is enough to prevent the intracluster medium from cooling, according to X-ray estimates. While to date the radio spectral distribution of 3C388 remains a rare case among radio galaxies, multi-frequency surveys performed with new-generation instruments will soon allow us to investigate whether more sources with the same characteristics exist.

show abstract

“…Despite this there is a growing number of polarised sources being found at low frequencies (e.g. Bernardi et al 2013;Mulcahy et al 2014;Jelić et al 2015;Orrù et al 2015;Lenc et al 2016;Van Eck et al 2018;O'Sullivan et al 2018;Neld et al 2018;Riseley et al 2018). J1235+5317 was discovered to be polarised at 144 MHz by Van Eck et al (2018), in LOFAR data imaged at an angular resolution of 4.3 .…”

Section: Introductionmentioning

confidence: 99%

The intergalactic magnetic field probed by a giant radio galaxy

O’Sullivan

Machalski

Eck

et al. 2019

A&A

Self Cite

View full text Add to dashboard Cite

Cosmological simulations predict that an intergalactic magnetic field (IGMF) pervades the large scale structure (LSS) of the Universe. Measuring the IGMF is important to determine its origin (i.e. primordial or otherwise). Using data from the LOFAR Two Metre Sky Survey (LoTSS), we present the Faraday rotation measure (RM) and depolarisation properties of the giant radio galaxy J1235+5317, at a redshift of z = 0.34 and 3.38 Mpc in size. We find a mean RM difference between the lobes of 2.5 ± 0.1 rad m −2 , in addition to small scale RM variations of ∼ 0.1 rad m −2 . From a catalogue of LSS filaments based on optical spectroscopic observations in the local universe, we find an excess of filaments intersecting the line of sight to only one of the lobes. Associating the entire RM difference to these LSS filaments leads to a gas density-weighted IGMF strength of ∼0.3 µG. However, direct comparison with cosmological simulations of the RM contribution from LSS filaments gives a low probability (∼5%) for an RM contribution as large as 2.5 rad m −2 , for the case of IGMF strengths of 10 to 50 nG. It is likely that variations in the RM from the Milky Way (on 11 scales) contribute significantly to the mean RM difference, and a denser RM grid is required to better constrain this contribution. In general, this work demonstrates the potential of the LOFAR telescope to probe the weak signature of the IGMF. Future studies, with thousands of sources with high accuracy RMs from LoTSS, will enable more stringent constraints on the nature of the IGMF.

show abstract

Wide-field LOFAR imaging of the field around the double-double radio galaxy B1834+620

Cited by 35 publications

References 52 publications

First look at the giant radio galaxy 3C 236 with LOFAR

First look at the giant radio galaxy 3C 236 with LOFAR

Radio spectral properties and jet duty cycle in the restarted radio galaxy 3C388

The intergalactic magnetic field probed by a giant radio galaxy

Contact Info

Product

Resources

About