Searching for correlations in simultaneous X-ray and UV emission in the narrow-line Seyfert 1 galaxy 1H 0707–495

Robertson, D.; Gallo, Luigi; Zoghbi, Abderahmen; Fabian, A. C.

doi:10.1093/mnras/stv1575

Cited by 48 publications

(42 citation statements)

References 41 publications

(48 reference statements)

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“…This epoch has, in the W1-band, FVar = 1.0 ± 0.1 %. These values are very similar to those of 1H 0707-495, being between the values for the two epochs presented in Robertson et al (2015).…”

Section: Discussionsupporting

confidence: 84%

“…We can also make a direct comparison between the fractional variability of IRAS 13224-3809 and 1H 0707-495. Robertson et al (2015) present the fractional variability of 1H 0707-495 in two sets of 4 continuous orbits. To compare the same timescales, we consider the 4 consecutive XMM-Newton orbits of IRAS 13224-3809 with OBSIDs 0780561501-0780561801 (other sections of consecutive orbits give similar results).…”

Section: Discussionmentioning

confidence: 99%

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Is there a UV/X-ray connection in IRAS 13224−3809?

Buisson

Lohfink

Alston

et al. 2018

Monthly Notices of the Royal Astronomical Society

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We present results from the optical, ultraviolet and X-ray monitoring of the NLS1 galaxy IRAS 13224-3809 taken with Swift and XMM-Newton during 2016. IRAS 13224-3809 is the most variable bright AGN in the X-ray sky and shows strong X-ray reflection, implying that the X-rays strongly illuminate the inner disc. Therefore, it is a good candidate to study the relationship between coronal X-ray and disc UV emission. However, we find no correlation between the X-ray and UV flux over the available ∼ 40 day monitoring, despite the presence of strong X-ray variability and the variable part of the UV spectrum being consistent with irradiation of a standard thin disc. This means either that the X-ray flux which irradiates the UV emitting outer disc does not correlate with the X-ray flux in our line of sight and/or that another process drives the majority of the UV variability. The former case may be due to changes in coronal geometry, absorption or scattering between the corona and the disc.

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Section: Discussionsupporting

confidence: 84%

Section: Discussionmentioning

confidence: 99%

Is there a UV/X-ray connection in IRAS 13224−3809?

Buisson

Lohfink

Alston

et al. 2018

Monthly Notices of the Royal Astronomical Society

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“…With simultaneous photometric time series in two filter bands, one can estimate upper limits to any time delays (or early arrivals) between the corresponding light curves under the simple assumption that the intrinsic light curve shapes are identical. We perform this analysis on our entire photometric time series (see Tables V-VI used to analyze variable time series with arbitrary sampling [59] (see, for example [60]). Constraints from time delays are presented in Table II, using the methods of §II A.…”

Section: E Constraints On Sme Modelsmentioning

confidence: 99%

Constraints on Lorentz invariance and CPT violation using optical photometry and polarimetry of active galaxies BL Lacertae and S5 B0716+714

et al. 2019

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Various quantum gravity approaches that extend beyond the standard model predict Lorentz Invariance and Charge-Parity-Time Violation at energies approaching the Planck scale. These models frequently predict a wavelength dependent speed of light, which would result in time delays between promptly emitted photons at different energies, as well as a wavelength-dependent rotation of the plane of linear polarization for photons resulting from vacuum birefringence. Here, we describe a pilot program with an automated system of small telescopes that can simultaneously conduct high cadence optical photometry and polarimetry of Active Galactic Nuclei (AGN) in multiple passbands. We use these observations as a proof-of-principle to demonstrate how such data can be used to test various Lorentz Violation models, including special cases of the Standard Model Extension (SME). In our initial campaign with this system, the Array Photo Polarimeter, we observed two AGN sources, including BL Lacertae at redshift z = 0.069, and S5 B0716+714 at z = 0.31. We demonstrate that optical polarimetry with a broadband Luminance filter combined with simultaneous Ic-band observations yields SME parameter constraints that are up to ∼10 and ∼30 times more sensitive than with a standard Ic-band filter, for SME models with mass dimension d = 5 and d = 6, respectively. Using only a small system of telescopes with an effective 0.45-m aperture, we further demonstrate d = 5 constraints for individual lines of sight that are within a factor of ∼1-10 in sensitivity to comparable constraints from optical polarimetry with a 3.6-m telescope. Such an approach could significantly improve existing SME constraints via a polarimetric all-sky survey of AGN with multiple 1-meter class telescopes.

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“…To determine the ACF and CCF between two light curves (i.e. the cross-correlation coefficient versus time-delay between the light curves) we compute the discrete correlation function (DCF) using 2 , which works well with unevenly sampled data (Edelson & Krolik 1988;Robertson et al 2015). Positive time-lags mean that the optical leads the near-IR, whereas negative time-lags means that the optical lags the near-IR.…”

Section: Light Curve Correlationsmentioning

confidence: 99%

Evidence for hot clumpy accretion flow in the transitional millisecond pulsar PSR J1023+0038

Shahbaz

Dallilar

Garner

et al. 2018

Monthly Notices of the Royal Astronomical Society

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We present simultaneous optical and near-infrared (IR) photometry of the millisecond pulsar PSR J1023+0038 during its low-mass X-ray binary phase. The r -and K s -band light curves show rectangular, flat-bottomed dips, similar to the X-ray mode-switching (active-passive state transitions) behaviour observed previously. The cross-correlation function (CCF) of the optical and near-IR data reveals a strong, broad negative anti-correlation at negative lags, a broad positive correlation at positive lags, with a strong, positive narrow correlation superimposed. The shape of the CCF resembles the CCF of black hole X-ray binaries but the time-scales are different. The features can be explained by reprocessing and a hot accretion flow close to the neutron star's magnetospheric radius. The optical emission is dominated by the reprocessed component, whereas the near-IR emission contains the emission from plasmoids in the hot accretion flow and a reprocessed component. The rapid active-passive state transition occurs when the hot accretion flow material is channelled onto the neutron star and is expelled from its magnetosphere. During the transition the optical reprocessing component decreases resulting in the removal of a blue spectral component. The accretion of clumpy material through the magnetic barrier of the neutron star produces the observed near-IR/optical CCF and variability. The dip at negative lags corresponds to the suppression of the near-IR synchrotron component in the hot flow, whereas the broad positive correlation at positive lags is driven by the increased synchrotron emission of the outflowing plasmoids. The narrow peak in the CCF is due to the delayed reprocessed component, enhanced by the increased X-ray emission.

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Searching for correlations in simultaneous X-ray and UV emission in the narrow-line Seyfert 1 galaxy 1H 0707–495

Cited by 48 publications

References 41 publications

Is there a UV/X-ray connection in IRAS 13224−3809?

Is there a UV/X-ray connection in IRAS 13224−3809?

Constraints on Lorentz invariance and CPT violation using optical photometry and polarimetry of active galaxies BL Lacertae and S5 B0716+714

Evidence for hot clumpy accretion flow in the transitional millisecond pulsar PSR J1023+0038

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