Results from regular monitoring of relativistic compact binaries like PSR 1913+16 are consistent with the dominant (quadrupole) order emission of gravitational waves (GWs). We show that observations ...associated with the binary black hole (BBH) central engine of blazar OJ 287 demand the inclusion of gravitational radiation reaction effects beyond the quadrupolar order. It turns out that even the effects of certain hereditary contributions to GW emission are required to predict impact flare timings of OJ 287. We develop an approach that incorporates this effect into the BBH model for OJ 287. This allows us to demonstrate an excellent agreement between the observed impact flare timings and those predicted from ten orbital cycles of the BBH central engine model. The deduced rate of orbital period decay is nine orders of magnitude higher than the observed rate in PSR 1913+16, demonstrating again the relativistic nature of OJ 287's central engine. Finally, we argue that precise timing of the predicted 2019 impact flare should allow a test of the celebrated black hole "no-hair theorem" at the 10% level.
We present the results of our power spectral density analysis for the BL Lac object OJ 287, utilizing the Fermi-LAT survey at high-energy γ-rays, Swift-XRT in X-rays, several ground-based telescopes ...and the Kepler satellite in the optical, and radio telescopes at GHz frequencies. The light curves are modeled in terms of continuous-time autoregressive moving average (CARMA) processes. Owing to the inclusion of the Kepler data, we were able to construct for the first time the optical variability power spectrum of a blazar without any gaps across ∼6 dex in temporal frequencies. Our analysis reveals that the radio power spectra are of a colored-noise type on timescales ranging from tens of years down to months, with no evidence for breaks or other spectral features. The overall optical power spectrum is also consistent with a colored noise on the variability timescales ranging from 117 years down to hours, with no hints of any quasi-periodic oscillations. The X-ray power spectrum resembles the radio and optical power spectra on the analogous timescales ranging from tens of years down to months. Finally, the γ-ray power spectrum is noticeably different from the radio, optical, and X-ray power spectra of the source: we have detected a characteristic relaxation timescale in the Fermi-LAT data, corresponding to ∼150 days, such that on timescales longer than this, the power spectrum is consistent with uncorrelated (white) noise, while on shorter variability timescales there is correlated (colored) noise.
ABSTRACT OJ 287 is a quasi-periodic quasar with roughly 12 year optical cycles. It displays prominent outbursts that are predictable in a binary black hole model. The model predicted a major optical ...outburst in 2015 December. We found that the outburst did occur within the expected time range, peaking on 2015 December 5 at magnitude 12.9 in the optical R-band. Based on Swift/XRT satellite measurements and optical polarization data, we find that it included a major thermal component. Its timing provides an accurate estimate for the spin of the primary black hole, . The present outburst also confirms the established general relativistic properties of the system such as the loss of orbital energy to gravitational radiation at the 2% accuracy level, and it opens up the possibility of testing the black hole no-hair theorem with 10% accuracy during the present decade.
Abstract
We present our photometric and spectroscopic observations of the peculiar transient AT2018cow. The multiband photometry covers from peak to ∼70 days, and the spectroscopy ranges from 5 to ...∼50 days. The rapid rise (
t
r
≲ 2.9 days), high luminosity (
M
V
,peak
∼ −20.8 mag), and fast decline after peak make AT2018cow stand out from any other optical transients, whereas we find that its light curves show a high resemblance to those of Type Ibn supernovae. Moreover, the spectral energy distribution remains at a high temperature of ∼14,000 K at
t
> 15 days after discovery. The spectra are featureless in the first 10 days, while some broad emission lines due to H, He, C, and O emerge later, with velocity declining from ∼14,000 to ∼3000 km s
−1
at the end of our observations. Narrow and weak He
I
emission lines emerge in the spectra at
t
> 20 days after discovery. These emission lines are reminiscent of the features seen in interacting supernovae like the Type Ibn and IIn subclasses. We fit the bolometric light curves with a model of circumstellar interaction and radioactive decay of
56
Ni and find a good fit with ejecta mass
M
ej
∼ 3.16
M
⊙
, circumstellar medium (CSM) mass
M
CSM
∼ 0.04
M
⊙
, and ejected
56
Ni mass
M
⊙
. The CSM shell might be formed in an eruptive mass ejection of the progenitor star. Furthermore, the host environment of AT2018cow implies a connection of AT2018cow with massive stars. Combining observational properties and the light-curve fitting results, we conclude that AT2018cow might be a peculiar interacting supernova that originated from a massive star.
Resumen Introducción El patrón de uso de fármacos antiepilépticos (FAE) durante el embarazo difiere entre países y está cambiando. Se desconoce en qué medida ello afecta a la población española. La ...eficacia de los nuevos fármacos en el control de las crisis es motivo de preocupación y puede haber cambiado a lo largo de los años debido a un mejor conocimiento de su uso durante el embarazo. Con el objetivo de analizar estos 2 aspectos reportamos los resultados del registro EURAP España durante un periodo de 12 años. Material y métodos Tras el consentimiento informado, las pacientes son incluidas en el registro y evaluadas al inicio del embarazo, al final del segundo y tercer trimestres, después del parto y al año del nacimiento. Para los objetivos de este estudio hemos analizado: FAE, tipo de epilepsia, frecuencia de crisis por trimestres y a lo largo del embarazo, porcentaje de pacientes libres de crisis, y frecuencia de malformaciones congénitas mayores. Hemos comparado estas variables en 2 periodos (junio de 2001-octubre de 2007) y (enero de 2008-mayo de 2015). Resultados Un total de 304 monoterapias del periodo antiguo se comparan con 127 del periodo nuevo. Observamos un ascenso del uso de levetiracetam (LEV) y un descenso del uso de carbamacepina (CBZ), fenitoína y fenobarbital; un leve descenso del uso de valproato (VPA), y un leve aumento de lamotrigina (LTG) y oxacarbamacepina (OXC). El tipo de epilepsia se mantiene estable para CBZ y VPA, pero cambia para LTG, con menos epilepsias generalizadas tratadas con este fármaco en el periodo nuevo. Ello no se asocia con un cambio significativo de la frecuencia de crisis, pero sí con un mejor control de las crisis de novo en el tercer trimestre. LEV se asocia a niveles de control de crisis similares a los de CBZ y VPA y mejor que con LTG. De las pacientes tratadas con LEV, un 64% tenían una epilepsia generalizada. Conclusiones El patrón de uso de los diferentes FAE durante el embarazo está cambiando en España, con menos uso de CBZ, fenitoína y fenobarbital y un aumento del uso de LEV. El tipo de epilepsia también cambia, con un porcentaje inferior de pacientes tratadas con LTG para epilepsias generalizadas. LEV controla las crisis de manera similar a los fármacos clásicos y mejor que la LTG.
We analyse the light curve in the R band of the blazar OJ287, gathered during the 2015/2016 observing season. We did a search for quasi-periodic oscillations (QPOs) using several methods over a wide ...range of timescales. No statistically significant periods were found in the high-frequency domain both in the ground-based data and in Kepler observations. In the longer-period domain, the Lomb-Scargle periodogram revealed several peaks above the 99% significance level. The longest one-about 95 days-corresponds to the innermost stable circular orbit (ISCO) period of the more massive black hole. The 43-day period could be an alias, or it can be attributed to accretion in the form of a two-armed spiral wave.
The prescription pattern of antiepileptic drugs (AEDs) during pregnancy is changing but to what extent this is occurring in Spain remains unknown. The efficacy of newer drugs for controlling seizures ...is a key issue and may have changed over the years as doctors gained familiarity with these drugs during pregnancy. To assess these 2 topics, we report the results from the Spanish EURAP register gathered over a 12-year period.
After signing informed consent forms, patients were included in the register and evaluated at onset of pregnancy, at the end of the second and third trimesters, after delivery, and one year after delivery. For the purposes of this study, we analysed AEDs, type of epilepsy, seizure frequency per trimester and throughout pregnancy, percentage of seizure-free pregnancies, and frequency of congenital malformations. We then compared data from 2 periods (June 2001 to October 2007 and January 2008 to May 2015).
We compared 304 monotherapies from the older period to 127 from the more recent one. There was a clear increase in the use of levetiracetam (LEV) with declining use of carbamazepine (CBZ), phenytoin, and phenobarbital; a slight decline in use of valproate (VPA), and a slight increase in the use of lamotrigine (LTG) and oxcarbazepine (OXC). Epilepsy types treated with CBZ and VPA remained unchanged, whereas fewer cases of generalised epilepsy were treated with LTG in the new period. This trend was not associated with significant changes in seizure frequency, but rather linked to better control over de novo seizures in the third trimester. LEV was similar to CBZ and VPA with regard to levels of seizure control, and more effective than LTG. Generalised epilepsy accounted for 64% of the cases treated with LEV.
The prescription pattern of AEDs during pregnancy has changed in Spain, with diminishing use of CBZ, phenytoin, and phenobarbital. Changes also reflect the type of epilepsy, since there is less use of LTG for generalised epilepsy. LEV provides similar seizure control to that of the older AEDs, and it is more effective and better than LTG.
El patrón de uso de fármacos antiepilépticos (FAE) durante el embarazo difiere entre países y está cambiando. Se desconoce en qué medida ello afecta a la población española. La eficacia de los nuevos fármacos en el control de las crisis es motivo de preocupación y puede haber cambiado a lo largo de los años debido a un mejor conocimiento de su uso durante el embarazo. Con el objetivo de analizar estos 2 aspectos reportamos los resultados del registro EURAP España durante un periodo de 12 años.
Tras el consentimiento informado, las pacientes son incluidas en el registro y evaluadas al inicio del embarazo, al final del segundo y tercer trimestres, después del parto y al año del nacimiento. Para los objetivos de este estudio hemos analizado: FAE, tipo de epilepsia, frecuencia de crisis por trimestres y a lo largo del embarazo, porcentaje de pacientes libres de crisis, y frecuencia de malformaciones congénitas mayores. Hemos comparado estas variables en 2periodos (junio de 2001-octubre de 2007 y enero de 2008-mayo de 2015).
Un total de 304 monoterapias del periodo antiguo se comparan con 127 del periodo nuevo. Observamos un ascenso del uso de levetiracetam (LEV) y un descenso del uso de carbamacepina (CBZ), fenitoína y fenobarbital; un leve descenso del uso de valproato (VPA), y un leve aumento de lamotrigina (LTG) y oxacarbamacepina (OXC). El tipo de epilepsia se mantiene estable para CBZ y VPA, pero cambia para LTG, con menos epilepsias generalizadas tratadas con este fármaco en el periodo nuevo. Ello no se asocia con un cambio significativo de la frecuencia de crisis, pero sí con un mejor control de las crisis de novo en el tercer trimestre. LEV se asocia a niveles de control de crisis similares a los de CBZ y VPA y mejor que con LTG. De las pacientes tratadas con LEV, un 64% tenían una epilepsia generalizada.
El patrón de uso de los diferentes FAE durante el embarazo está cambiando en España, con menos uso de CBZ, fenitoína y fenobarbital y un aumento del uso de LEV. El tipo de epilepsia también cambia, con un porcentaje inferior de pacientes tratadas con LTG para epilepsias generalizadas. LEV controla las crisis de manera similar a los fármacos clásicos y mejor que la LTG.
The prescription pattern of antiepileptic drugs (AEDs) during pregnancy is changing but to what extent this is occurring in Spain remains unknown. The efficacy of newer drugs for controlling seizures ...is a key issue and may have changed over the years as doctors gained familiarity with these drugs during pregnancy. To assess these 2 topics, we report the results from the Spanish EURAP register gathered over a 12-year period.
After signing informed consent forms, patients were included in the register and evaluated at onset of pregnancy, at the end of the second and third trimesters, after delivery, and one year after delivery. For the purposes of this study, we analysed AEDs, type of epilepsy, seizure frequency per trimester and throughout pregnancy, percentage of seizure-free pregnancies, and frequency of congenital malformations. We then compared data from 2 periods (June 2001-October 2007) and (January 2008-May 2015) RESULTS: We compared 304 monotherapies from the older period to 127 from the more recent one. There was a clear increase in the use of levetiracetam (LEV) with declining use of carbamazepine (CBZ), phenytoin, and phenobarbital; a slight decline in use of valproate (VPA), and a slight increase in the use of lamotrigine (LTG) and oxcarbazepine (OXC). Epilepsy types treated with CBZ and VPA remained unchanged, whereas fewer cases of generalised epilepsy were treated with LTG in the new period. This trend was not associated with significant changes in seizure frequency, but rather linked to better control over de novo seizures in the third trimester. LEV was similar to CBZ and VPA with regard to levels of seizure control, and more effective than LTG. Generalised epilepsy accounted for 64% of the cases treated with LEV.
The prescription pattern of AEDs during pregnancy has changed in Spain, with diminishing use of CBZ, phenytoin, and phenobarbital. Changes also reflect the type of epilepsy, since there is less use of LTG for generalised epilepsy. LEV provides similar seizure control to that of the older AEDs, and it is more effective and better than LTG.
OJ 287 is a BL Lacertae type quasar in which the active galactic nucleus (AGN) outshines the host galaxy by an order of magnitude. The only exception to this may be at minimum light when the AGN ...activity is so low that the host galaxy may make quite a considerable contribution to the photometric intensity of the source. Such a dip or a fade in the intensity of OJ 287 occurred in November 2017, when its brightness was about 1.75 magnitudes lower than the recent mean level. We compare the observations of this fade with similar fades in OJ 287 observed earlier in 1989, 1999, and 2010. It appears that there is a relatively strong reddening of the B\(-\)V colours of OJ 287 when its V-band brightness drops below magnitude 17. Similar changes are also seen V\(-\)R, V\(-\)I, and R\(-\)I colours during these deep fades. These data support the conclusion that the total magnitude of the host galaxy is \(V=18.0 \pm 0.3\), corresponding to \(M_{K}=-26.5 \pm 0.3\) in the K-band. This is in agreement with the results, obtained using the integrated surface brightness method, from recent surface photometry of the host. These results should encourage us to use the colour separation method also in other host galaxies with strongly variable AGN nuclei. In the case of OJ 287, both the host galaxy and its central black hole are among the biggest known, and its position in the black hole mass-galaxy mass diagram lies close to the mean correlation.
Euclid preparation Deshpande, A C; Kitching, T; Hall, A ...
Astronomy and astrophysics (Berlin),
04/2024, Letnik:
684
Journal Article
Recenzirano
This work considers which higher order modeling effects on the cosmic shear angular power spectra must be taken into account for Euclid. We identified the relevant terms and quantified their ...individual and cumulative impact on the cosmological parameter inferences from Euclid. We computed the values of these higher order effects using analytic expressions and calculated the impact on cosmological parameter estimations using the Fisher matrix formalism. We reviewed 24 effects and determined the ones that potentially need to be accounted for, namely: the reduced shear approximation, magnification bias, source-lens clustering, source obscuration, local Universe effects, and the flat Universe assumption. After computing these effects explicitly and calculating their cosmological parameter biases, using a maximum multipole of ℓ = 5000, we find that the magnification bias, source-lens clustering, source obscuration, and local Universe terms individually produce significant (> 0.25σ) cosmological biases in one or more parameters; accordingly, these effects must be accounted for and warrant further investigation. In total, we find biases in Ωm, Ωb, h, and σ8 of 0.73σ, 0.28σ, 0.25σ, and −0.79σ, respectively, for the flat ΛCDM. For the w0waCDM case, we found biases in Ωm, Ωb, h, ns, σ8, and wa of 1.49σ, 0.35σ, −1.36σ, 1.31σ, −0.84σ, and −0.35σ, respectively. These are increased relative to the ΛCDM due to additional degeneracies as a function of redshift and scale.
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