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MOMO. VI. Multifrequency Radio Variability of the Blazar OJ 287 from 2015 to 2022, Absence of Predicted 2021 Pecursor-flare Activity, and a New Binary Interpretation of the 2016/2017 Outburst
No full textBased on our dedicated Swift monitoring program, MOMO, OJ 287 is one of the best-monitored blazars in the X-ray–UV–optical regime. Here, we report results from our accompanying, dense, multifrequency (1.4–44 GHz) radio monitoring of OJ 287 between 2015 and 2022 covering a broad range of activity states. Fermi γ-ray observations were added. We characterize the radio flux and spectral variability in detail, including discrete correlation function and other variability analyses, and discuss its connection with the multiwavelength emission. Deep fades of the radio and optical–UV fluxes are found to occur every 1–2 yr. Further, it is shown that a precursor flare of thermal bremsstrahlung predicted by one of the binary supermassive black hole (SMBH) models of OJ 287 was absent. We then focus on the nature of the extraordinary, nonthermal, 2016/2017 outburst that we initially discovered with Swift. We interpret it as the latest of the famous optical double-peaked outbursts of OJ 287, favoring binary scenarios that do not require a highly precessing secondary SMBH
TOI 560: Two Transiting Planets Orbiting a K Dwarf Validated with iSHELL, PFS, and HIRES RVs
No full textWe validate the presence of a two-planet system orbiting the 0.15–1.4 Gyr K4 dwarf TOI 560 (HD 73583). The system consists of an inner moderately eccentric transiting mini-Neptune (TOI 560 b, P = 6.3980661_(−0.0000097)^(+0.0000095) days, e = 0.294_(−0.062)^(+0.13), M = 0.94_(-0.23)^(+0.31)M_(Nep) initially discovered in the Sector 8 Transiting Exoplanet Survey Satellite (TESS) mission observations, and a transiting mini-Neptune (TOI 560 c, P = 18.8805_(−0.0011)^(+0.0024) days, M = 1.32_(−0.32)^(+0.29)M_(Nep) discovered in the Sector 34 observations, in a rare near-1:3 orbital resonance. We utilize photometric data from TESS Spitzer, and ground-based follow-up observations to confirm the ephemerides and period of the transiting planets, vet false-positive scenarios, and detect the photoeccentric effect for TOI 560 b. We obtain follow-up spectroscopy and corresponding precise radial velocities (RVs) with the iSHELL spectrograph at the NASA Infrared Telescope Facility and the HIRES Spectrograph at Keck Observatory to validate the planetary nature of these signals, which we combine with published Planet Finder Spectrograph RVs from the Magellan Observatory. We detect the masses of both planets at >3σ significance. We apply a Gaussian process (GP) model to the TESS light curves to place priors on a chromatic RV GP model to constrain the stellar activity of the TOI 560 host star, and confirm a strong wavelength dependence for the stellar activity demonstrating the ability of near-IR RVs to mitigate stellar activity for young K dwarfs. TOI 560 is a nearby moderately young multiplanet system with two planets suitable for atmospheric characterization with the James Webb Space Telescope and other upcoming missions. In particular, it will undergo six transit pairs separated by <6 hr before 2027 June
Starlight-polarization-based tomography of the magnetized ISM: PASIPHAE’s line-of-sight inversion method
No full textWe present the first Bayesian method for tomographic decomposition of the plane-of-sky orientation of the magnetic field with the use of stellar polarimetry and distance. This standalone tomographic inversion method presents an important step forward in reconstructing the magnetized interstellar medium (ISM) in three dimensions within dusty regions. We develop a model in which the polarization signal from the magnetized and dusty ISM is described by thin layers at various distances, a working assumption which should be satisfied in small-angular circular apertures. Our modeling makes it possible to infer the mean polarization (amplitude and orientation) induced by individual dusty clouds and to account for the turbulence-induced scatter in a generic way. We present a likelihood function that explicitly accounts for uncertainties in polarization and parallax. We develop a framework for reconstructing the magnetized ISM through the maximization of the log-likelihood using a nested sampling method. We test our Bayesian inversion method on mock data, representative of the high Galactic latitude sky, taking into account realistic uncertainties from Gaia and as expected for the optical polarization survey PASIPHAE according to the currently planned observing strategy. We demonstrate that our method is effective at recovering the cloud properties as soon as the polarization induced by a cloud to its background stars is higher than ~0.1% for the adopted survey exposure time and level of systematic uncertainty. The larger the induced polarization is, the better the method’s performance, and the lower the number of required stars. Our method makes it possible to recover not only the mean polarization properties but also to characterize the intrinsic scatter, thus creating new ways to characterize ISM turbulence and the magnetic field strength. Finally, we apply our method to an existing data set of starlight polarization with known line-of-sight decomposition, demonstrating agreement with previous results and an improved quantification of uncertainties in cloud properties
A Broad-line Quasar with Unexplained Extreme Velocity Offsets: Post-shock Outflow?
No full textThe quasar SDSS 0956 + 5128 exhibits three distinct velocity components with large offsets in emission: the systemic velocity of [O ii], [O iii], and [Ne iii] narrow lines have redshift z = 0.7142; the broad Mg ii line is shifted by −1200 km s⁻¹ with respect to the narrow lines; the broad Hα and Hβ lines are at −4100 km s⁻¹. We present new Hubble Space Telescope spectra of Lyα and C iv emission lines and high-resolution images of the quasar. The offsets of these lines are consistent with the velocity component of the Balmer emission, and the photometry in optical and near-infrared wavelengths does not show any signs of recent mergers in the host galaxy or irregularities in the location of the quasar. The data do not confirm predictions of the previous most likely hypotheses involving a special orientation and morphology of the quasar disk, such as in the recoiling black hole scenario, neither it is consistent with accretion disk winds. Instead, based on the cumulative evidence, we propose a new scenario, in which the broad-line region is in the state of outflow caused by a strong shock wave, with a supernova as a possible event for producing the shock ejecta
GOALS-JWST: Mid-infrared Spectroscopy of the Nucleus of NGC 7469
No full textWe present mid-infrared spectroscopic observations of the nucleus of the nearby Seyfert galaxy NGC 7469 taken with the MIRI instrument on the James Webb Space Telescope (JWST) as part of Directors Discretionary Time Early Release Science program 1328. The high-resolution nuclear spectrum contains 19 emission lines covering a wide range of ionization. The high-ionization lines show broad, blueshifted emission reaching velocities up to 1700 km s⁻¹ and FWHM ranging from ∼500 to 1100 km s⁻¹. The width of the broad emission and the broad-to-narrow line flux ratios correlate with ionization potential. The results suggest a decelerating, stratified, AGN-driven outflow emerging from the nucleus. The estimated mass outflow rate is 1–2 orders of magnitude larger than the current black hole accretion rate needed to power the AGN. Eight pure rotational H₂ emission lines are detected with intrinsic widths ranging from FWHM ∼125 to 330 km s⁻¹. We estimate a total mass of warm H₂ gas of ∼1.2 × 10⁷ M_⊙ in the central 100 pc. The PAH features are extremely weak in the nuclear spectrum, but a 6.2 μm PAH feature with an equivalent width of ∼0.07 μm and a flux of 2.7 × 10⁻¹⁷ W m⁻² is detected. The spectrum is steeply rising in the mid-infrared, with a silicate strength of ∼0.02, significantly smaller than seen in most PG QSOs but comparable to other Seyfert 1s. These early MIRI mid-infrared IFU data highlight the power of JWST to probe the multiphase interstellar media surrounding actively accreting supermassive black holes
Gifts hidden in shadowy genome islands
No full textDespite being typically perceived as “clonal” organisms, bacteria and archaea possess numerous mechanisms to share and co-opt genetic material from other lineages. Several mechanisms for horizontal gene transfer have been discovered, but the high mosaicity observed in many bacterial genomes outscales that explained by known mechanisms, hinting at yet undiscovered processes. In this issue of Cell, Hackl et al. introduce a new category of mobile genetic elements called tycheposons, providing a novel mechanism that contributes to the prodigious genomic diversity within microbial populations. The discovery and characterization of tycheposons prompts a reevaluation of microbial diversification in complex environments
Inverse Power Flow Problem
No full textWe formulate an inverse power flow problem that infers a nodal admittance matrix from voltage and current phasors measured at a number of buses. We show that the admittance matrix can be uniquely identified from a sequence of measurements corresponding to different steady states when every node in the system is equipped with a measurement device, and a Kron-reduced admittance matrix can be determined even if some nodes in the system are not monitored (hidden nodes). We propose an effective algorithm to uncover the actual admittance matrix of a radial system with hidden nodes from its Kron-reduced admittance matrix
Linker mediated enhancement in reusability and regulation of Pb(II) removal mechanism of Cu-centered MOFs
No full textOur study demonstrates improved hydrolytic stability of Cu-centered MOFs through linker selection, resulting in enhanced and selective Pb(II) removal with contrasting removal mechanisms. A simple one-pot solvothermal process was employed to synthesize Copper 1,3,5-Benzene-Tricarboxylic Acid (Cu-BTC) MOF, Copper Imidazolate (Cu-Im) MOF and Copper Nicotinic Acid (Cu-NA) MOF, respectively. The synthesis of these MOFs was confirmed using characterization techniques such as XPS, XRD, FTIR and ICP-OES. Water stability studies using experimental and modelling approaches demonstrated that substituting the 1,3,5-benzene-tricarboxylic acid linker with either imidazolate or nicotinic acid, enhanced the hydrostability of the Cu-centered MOF from under 2 h to over 48 h, while showing a high Pb(II) adsorption capacity of 492 mg g−1. This improved hydrostability was observed across acidic and basic pH and at elevated temperatures. The improved stability of Cu-Im significantly enhanced its reusability and showed Pb(II) adsorption for 3 cycles, with 99.5 % removal efficiency at the end of the 3rd cycle and a desorption efficiency of 92.7 %. The experimental data obtained were substantiated with modelling studies (density functional theory) to gain insights into the 2D structure of Cu-Im and compare the hydrolytic stability of Cu-BTC and Cu-Im. Cu-Im, when tested on textile effluent showed a Pb(II) removal efficiency of 99 % within 2 h of treatment. This study opens up the possibility of using linker selection and design as a strategy to enhance the hydrostability of Cu-centered MOFs and in the process improve its applicability for environmental remediation applications
Combining Choice and Response Time Data: A Drift-Diffusion Model of Mobile Advertisements
No full textEndogenous response time data are increasingly becoming available to applied researchers of economic choices. However, the usefulness of such data for preference estimation is unclear. Here, we adapt a sequential sampling model—previously validated to jointly explain subjects’ choices and response times in laboratory experiments—to model users’ responses to video advertisements on mobile devices in a field setting. Our estimates of utility correlate positively with out-of-sample measures of ad engagement, thus providing external validation of the value of incorporating endogenous response time information into a choice model. We then use the model estimates to assess the effectiveness of manipulating attention toward an advertisement at the beginning of a decision. Counterfactual simulations predict that making an ad “nonskippable” (requiring users to watch some portion of the ad)—as is the practice of some online platforms (e.g., YouTube)—generates only modest increases in click-through rates and revenue
A kirigami-enabled electrochromic wearable variable-emittance device for energy-efficient adaptive personal thermoregulation
No full textFor centuries, people have put effort to improve the thermal performance of clothing to adapt to varying temperatures. However, most clothing we wear today only offers a single-mode insulation. The adoption of active thermal management devices, such as resistive heaters, Peltier coolers, and water recirculation, is limited by their excessive energy consumption and form factor for long-term, continuous, and personalized thermal comfort. In this paper, we developed a wearable variable-emittance (WeaVE) device, enabling the tunable radiative heat transfer coefficient to fill the missing gap between thermoregulation energy efficiency and controllability. WeaVE is an electrically driven, kirigami-enabled electrochromic thin-film device that can effectively tune the midinfrared thermal radiation heat loss of the human body. The kirigami design provides stretchability and conformal deformation under various modes and exhibits excellent mechanical stability after 1,000 cycles. The electronic control enables programmable personalized thermoregulation. With less than 5.58 mJ/cm² energy input per switching, WeaVE provides 4.9°C expansion of the thermal comfort zone, which is equivalent to a continuous power input of 33.9 W/m². This nonvolatile characteristic substantially decreases the required energy while maintaining the on-demand controllability, thereby providing vast opportunities for the next generation of smart personal thermal managing fabrics and wearable technologies