Evidence of jet-induced optical microvariability in radio-loud narrow-line Seyfert 1 galaxies

Ojha, Vineet; Jha, Vijay Kumar; Chand, Hum; Singh, Veeresh

doi:10.1093/mnras/stac1627

Cited by 3 publications

(1 citation statement)

References 120 publications

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“…Orphaned tracklets might appear due to rapidly dissipating dust clouds arising from the catastrophic collision of small asteroids (LSST Science Collaboration et al 2009, Section 5.6.1). In nonthermal extragalactic active galactic nuclei, optical microvariations on timescales of minutes to hours have been studied in radio-loud narrow-line Seyfert 1 galaxies (Ojha et al 2022) and in relativistic blazar jets (Chand et al 2022). In stellar astrophysics, there may be magnetic, accretional, collisional, or shock breakout explosive phenomena that we do not know.…”

Section: Known and Unknown Unknownsmentioning

confidence: 99%

An Evenly Spaced LSST Cadence for Rapidly Variable Stars

Feigelson,

Bianco,

Bonito

2023

ApJS

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Stars exhibit a bewildering variety of rapidly variable behaviors ranging from explosive magnetic flares to stochastically changing accretion to periodic pulsations or rotation. The principal Rubin Observatory Legacy Survey of Space and Time (LSST) surveys will have cadences too sparse and irregular to capture many of these phenomena. We propose here an LSST microsurvey to observe a single Galactic field, rich in unobscured stars, in a continuous sequence of 30 s exposures for one long winter night in a single photometric band. The result will be a unique data set of ∼1 million regularly spaced stellar light curves. The light curves will constitute a comprehensive collection of late-type stellar flaring, but also other classes like short-period binary systems and cataclysmic variables, young stellar objects, and ultrashort-period exoplanets. An unknown variety of anomalous solar system, Galactic, and extragalactic variables and transients may also be present. A powerful array of statistical procedures can be applied to individual light curves from the long-standing fields of time series analysis, signal processing, and econometrics. Dozens of “features” describing the variability can be extracted and the ensemble of light curves can be subject to advanced machine-learning clustering procedures. This will give a unique, authoritative, objective taxonomy of the rapidly variable sky derived from identically cadenced light curves. This microsurvey is best performed early in the Rubin Observatory program, and the results can inform the wider community on the best approaches to variable star identification and classification from the sparse, irregular cadences that dominate the planned surveys.

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Section: Known and Unknown Unknownsmentioning

confidence: 99%

An Evenly Spaced LSST Cadence for Rapidly Variable Stars

Feigelson,

Bianco,

Bonito

2023

ApJS

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Multiwavelength variability of γ-ray emitting narrow-line Seyfert 1 galaxies

Yao

Komossa

2023

Monthly Notices of the Royal Astronomical Society

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As one of the drivers of feedback in active galactic nuclei (AGN), the jets launched from supermassive black holes (SMBHs) are important for understanding the co-evolution of SMBHs and their host galaxies. However, the formation of AGN jets is far from clear. The discovery of γ-ray narrow-line Seyfert 1 (NLS1) galaxies during the past two decades has provided us with a new means of studying the link between jets and accretion processes and the formation of jets. Here we explore the coupling of jet and accretion discs in seven bright γ-ray NLS1 galaxies by studying simultaneous optical/UV and X-ray observations of these systems taken by Swift. The results show that, except for 1H 0323+342 in which the X-rays are significantly contributed from the accretion disc, the observed X-ray emission of the other sources is dominated by the jet, and accretion process makes little contribution if not absent. Although the origin of the X-ray emission is different, the broad-band spectral shape characterized by αox and the X-ray flux is found to follow the same evolutionary trend in 1H 0323+342, PMN J0948+0022, and PKS 1502+036. For the remaining sources, the trend is not observed or the sampling is not dense enough.

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Intra-night optical variability of peculiar narrow-line Seyfert 1 galaxies with enigmatic jet behaviour

Ojha,

Singh,

Berton

et al. 2023

Monthly Notices of the Royal Astronomical Society: Letters

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Variability studies of active galactic nuclei are a powerful diagnostic tool in understanding the physical processes occurring in disk-jet regions, unresolved by direct imaging with currently available techniques. Here, we report the first attempt to systematically characterize intra-night optical variability (INOV) for a sample of seven apparently radio-quiet narrow-line Seyfert 1 galaxies (RQNLSy1s) that had shown recurring flaring at 37 GHz in the radio observations at Metsähovi Radio Observatory (MRO), indicating the presence of relativistic jets in them, but no evidence for relativistic jets in the recent radio observations of Karl G. Jansky Very Large Array (JVLA) at 1.6, 5.2, and 9.0 GHz. We have conducted a total of 28 intra-night sessions, each lasting ≥ 3 hrs for this sample, resulting in an INOV duty cycle ($\overline{DC} ~\sim$20 %) similar to that reported for γ-ray-NLSy1s (DC ∼25 % - 30 %), that display blazar-like INOV. This in turn infers the presence of relativistic jet in our sample sources. Thus, it appears that even lower-mass (MBH ∼ 106 M⊙) RQNLSy1 galaxies can maintain blazar-like activities. However, we note that the magnetic reconnection in the magnetosphere of the black hole can also be a viable mechanism to give rise to the INOV from these sources.

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Evidence of jet-induced optical microvariability in radio-loud narrow-line Seyfert 1 galaxies

Cited by 3 publications

References 120 publications

An Evenly Spaced LSST Cadence for Rapidly Variable Stars

An Evenly Spaced LSST Cadence for Rapidly Variable Stars

Multiwavelength variability of γ-ray emitting narrow-line Seyfert 1 galaxies

Intra-night optical variability of peculiar narrow-line Seyfert 1 galaxies with enigmatic jet behaviour

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