Giant Radio Quasars: Composite Optical Spectra

Kuźmicz, A.; Sethi, Sagar; Jamrozy, M.

doi:10.3847/1538-4357/ac27ad

Cited by 5 publications

(3 citation statements)

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“…One of the hypotheses that may explain the formation of large-scale radio lobes is that the central engine, which is responsible for generating radio jets, has some specific properties. This hypothesis was examined in a series of papers e.g., Ishwara-Chandra & Saikia (1999), Kuźmicz & Jamrozy (2012, 2021, Kuzmicz et al (2019Kuzmicz et al ( , 2021, and Dabhade et al (2020). However, finding a link between AGN variability and the radio jet's ejection at large distances from the host galaxy requires long-term monitoring of a large sample of such sources.…”

Section: Introductionmentioning

confidence: 99%

Optical Variability of Eight FRII-type Quasars with 13 yr Photometric Light Curves

Kuźmicz

Goyal

Zoła

et al. 2022

ApJS

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We characterize the optical variability properties of eight lobe-dominated radio quasars (QSOs): B2 0709+37, FBQS J095206.3+235245, PG 1004+130, [HB89] 1156+631, [HB89] 1425+267, [HB89] 1503+691, [HB89] 1721+343, and 4C +74.26, systematically monitored for a duration of 13 yr since 2009. The quasars are radio-loud objects with extended radio lobes that indicate their orientation close to the sky plane. Five of the eight QSOs are classified as giant radio quasars. All quasars showed variability during our monitoring, with magnitude variations between 0.3 and 1 mag for the least variable and the most variable QSOs, respectively. We performed both structure function (SF) analysis and power spectral density (PSD) analysis for the variability characterization and search for characteristic timescales and periodicities. As a result of our analysis, we obtained relatively steep SF slopes (α ranging from 0.49 to 0.75) that are consistent with the derived PSD slopes (∼2–3). All the PSDs show a good fit to single power-law forms, indicating a red-noise character of variability between timescales of ∼13 yr and weeks. We did not measure reliable characteristic timescales of variability from the SF analysis, which indicates that the duration of the gathered data is too short to reveal them. The absence of bends in the PSDs (change of slope from ≥1 to ∼0) on longer timescales indicates that optical variations are most likely caused by thermal instabilities in the accretion disk.

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Section: Introductionmentioning

confidence: 99%

Optical Variability of Eight FRII-type Quasars with 13 yr Photometric Light Curves

Kuźmicz

Goyal

Zoła

et al. 2022

ApJS

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“…On the converse, the RL ('jetted') sources are mainly Pop. B and populate particular bins of the optical plane, mostly in B1 and B + (Zamfir et al 2008 ;Ku źmicz, Sethi & Jamrozy 2021 ).…”

Section: Main Sequence Optical Planementioning

confidence: 99%

Optical and near-UV spectroscopic properties of low-redshift jetted quasars in the main sequence context

Mengistue,

Del Olmo,

Marziani

et al. 2023

Monthly Notices of the Royal Astronomical Society

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This paper presents new optical and near-UV spectra of 11 extremely powerful jetted quasars, with radio to optical flux density ratio > 103, that concomitantly cover the low-ionization emission of Mg iiλ2800 and h β as well as the Fe ii blends in the redshift range 0.35 ≲ z ≲ 1. We aim to quantify broad emission line differences between radio-loud (RL) and radio-quiet (RQ) quasars by using the 4D eigenvector 1 parameter space and its Main Sequence (MS) and to check the effect of powerful radio ejection on the low ionization broad emission lines. The h β and Mg iiλ2800 emission lines were measured by using non-linear multicomponent fittings as well as by analysing their full profile. We found that broad emission lines show large redward asymmetry both in h β and Mg iiλ2800. The location of our RL sources in a UV plane looks similar to the optical one, with weak Fe iiUV emission and broad Mg iiλ2800. We supplement the 11 sources with large samples from previous work to gain some general inferences. We found that, compared to RQ, our extreme RL quasars show larger median h β full width at half maximum (FWHM), weaker Fe ii emission, larger MBH, lower Lbol/LEdd, and a restricted bf space occupation in the optical and UV MS planes. The differences are more elusive when the comparison is carried out by restricting the RQ population to the region of the MS occupied by RL sources, albeit an unbiased comparison matching MBH and Lbol/LEdd suggests that the most powerful RL quasars show the highest redward asymmetries in h β.

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“…They are thought to grow in underdense environments and/or are supplied with continuous jet power for a long duration (∼ 10 8 yr), thereby allowing them to scale larger distances. Efforts to constrain models explaining the giant nature of GRSs are still ongoing (Gopal-Krishna et al 1989;Subrahmanyan et al 1996;Saripalli et al 2005;Hardcastle et al 2019;Dabhade et al 2020b,a;Bruni et al 2020;Kuźmicz et al 2021;Mahato et al 2022). The nature of GRSs has been reviewed in Komberg & Pashchenko (2009) and more recently in Dabhade et al (2022).…”

Section: Introductionmentioning

confidence: 99%

Barbell-shaped giant radio galaxy with ∼100 kpc kink in the jet

Dabhade

Shimwell

Saikia

et al. 2022

A&A

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We present for the first time a study of peculiar giant radio galaxy (GRG) J223301+131502 using deep multi-frequency radio observations from GMRT (323, 612, and 1300 MHz) and LOFAR (144 MHz) along with optical spectroscopic observations with the WHT 4.2m optical telescope. Our observations have firmly established its redshift of 0.09956 and unveiled its exceptional jet structure extending more than ∼ 200 kpc leading to a peculiar kink structure of ∼ 100 kpc. We measure the overall size of this GRG to be ∼ 1.83 Mpc; it exhibits lobes without any prominent hotspots and closely resembles a barbell. Our deep low-frequency radio maps clearly reveal the steep-spectrum diffuse emission from the lobes of the GRG. The magnetic field strength of ∼ 5 µG and spectral ages between about 110 to 200 mega years for the radio lobes were estimated using radio data from LOFAR 144 MHz observations and GMRT 323 and 612 MHz observations. We discuss the possible causes leading to the formation of the observed kink feature for the GRG, which include precession of the jet axis, development of instabilities and magnetic reconnection. Despite its enormous size, the Barbell GRG is found to be residing in a low-mass (M200 ∼ 10 14 M ) galaxy cluster. This GRG with two-sided large-scale jets with a kink and diffuse outer lobes residing in a cluster environment, provides an opportunity to explore the structure and growth of GRGs in different environments.

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Giant Radio Quasars: Composite Optical Spectra

Cited by 5 publications

References 50 publications

Optical Variability of Eight FRII-type Quasars with 13 yr Photometric Light Curves

Optical Variability of Eight FRII-type Quasars with 13 yr Photometric Light Curves

Optical and near-UV spectroscopic properties of low-redshift jetted quasars in the main sequence context

Barbell-shaped giant radio galaxy with ∼100 kpc kink in the jet

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