Aims. We present the first multi-wavelength study of Mrk 501 including very-high-energy (VHE) γ-ray observations simultaneous to X-ray polarization measurements from the Imaging X-ray Polarimetry Explorer (IXPE). Met...
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Aims. We present the first multi-wavelength study of Mrk 501 including very-high-energy (VHE) γ-ray observations simultaneous to X-ray polarization measurements from the Imaging X-ray Polarimetry Explorer (IXPE). Methods. We use radio-to-VHE data from a multi-wavelength campaign organized between 2022-03-01 and 2022-07-19 (MJD 59639 to MJD 59779). The observations were performed by MAGIC, Fermi-LAT, NuSTAR, Swift (XRT and UVOT), and several instruments covering the optical and radio bands to complement the IXPE pointings. We characterize the dynamics of the broad-band emission around the X-ray polarization measurements through its multi-band fractional variability and correlations, and compare changes observed in the polarization degree to changes seen in the broad-band emission using a multi-zone leptonic scenario. Results. During the IXPE pointings, the VHE state is close to the average behavior with a 0.2-1 TeV flux of 20% - 50% the emission of the Crab Nebula. Additionally, it shows low variability and a hint of correlation between VHE and X-rays. Despite the average VHE activity, an extreme X-ray behavior is measured for the first two IXPE pointings in March 2022 (MJD 59646 to 59648 and MJD 59665 to 59667) with a synchrotron peak frequency > 1 keV. For the third IXPE pointing in July 2022 (MJD 59769 to 59772), the synchrotron peak shifts towards lower energies and the optical/X-ray polarization degrees drop. All three IXPE epochs show an atypically low Compton dominance in the γ-rays. The X-ray polarization is systematically higher than at lower energies, suggesting an energy-stratification of the jet. While during the IXPE epochs the polarization angle in the X-ray, optical and radio bands align well, we find a clear discrepancy in the optical and radio polarization angles in the middle of the campaign. Such results further strengthen the hypothesis of an energy-stratified jet. We model the broad-band spectra simultaneous to the IXPE pointings assuming a compa
Aims. To probe the magnetic field geometry and particle acceleration mechanism in the relativistic jets of supermassive black holes. Methods. We conducted a polarimetry campaign from radio to X-ray wavelengths of the ...
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Aims. To probe the magnetic field geometry and particle acceleration mechanism in the relativistic jets of supermassive black holes. Methods. We conducted a polarimetry campaign from radio to X-ray wavelengths of the high-synchrotron-peak (HSP) blazar Mrk 421, including Imaging X-ray Polarimetry Explorer (IXPE) measurements on 2022 December 6-8. During the IXPE observation, we also monitored Mrk 421 using Swift-XRT and obtained a single observation with XMM-Newton to improve the X-ray spectral analysis. The time-averaged X-ray polarization was determined consistently based on the event-by-event Stokes parameter analysis, spectropolarimetric fit, and maximum likelihood methods. We examined the polarization variability over both time and energy, the latter via analysis of IXPE data obtained over a time span of 7 months. Results. We detected X-ray polarization of Mrk 421 with a degree of ΠX=14±1% and an electric-vector position angle ψX=107±3◦ in the 2-8 keV band. From the time variability analysis, we find a significant episodic variation in ψX. During 7 months from the first IXPE pointing of Mrk 421 in 2022 May, ψX varied across the range of 0◦ to 180◦, while ΠX maintained similar values within ∼10-15%. Furthermore, a swing in ψX in 2022 June was accompanied by simultaneous spectral variations. The results of the multiwavelength polarimetry show that the X-ray polarization degree was generally ∼2-3 times greater than that at longer wavelengths, while the polarization angle fluctuated. Additionally, based on radio, infrared, and optical polarimetry, we find that rotation of ψ occurred in the opposite direction with respect to the rotation of ψX over longer timescales at similar epochs. Conclusions. The polarization behavior observed across multiple wavelengths is consistent with previous IXPE findings for HSP blazars. This result favors the energy-stratified shock model developed to explain variable emission in relativistic jets. We consider two versions of the model,
—In this letter, the channel estimation problem is studied for wireless communication systems assisted by large intelligent surface. Due to features of assistant channel, channel estimation (CE) problem for the inves...
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PD-L1 aptamer-based spherical nucleic acids (SNAs) were designed that consist of oxaliplatin (OXA) encapsulated in a metal–organic framework (MOF) nanoparticle core and a dense shell of PD-L1 aptamer (denoted as M@O-...
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PD-L1 aptamer-based spherical nucleic acids (SNAs) were designed that consist of oxaliplatin (OXA) encapsulated in a metal–organic framework (MOF) nanoparticle core and a dense shell of PD-L1 aptamer (denoted as M@O-A), as reported by Zhengyu Jin, Jie Tian, Yang Du, and co-workers in their Research Article (e202214750). Upon light irradiation, the versatile M@O-A allows for robust photo-immunotherapy against cancer by combining photodynamic therapy, chemotherapy, and immunotherapy in one nanoplatform with reduced immunotoxicity.
PD-L1 aptamer-based spherical nucleic acids (SNAs) were designed that consist of oxaliplatin (OXA) encapsulated in a metal–organic framework (MOF) nanoparticle core and a dense shell of PD-L1 aptamer (denoted as M@O-...
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PD-L1 aptamer-based spherical nucleic acids (SNAs) were designed that consist of oxaliplatin (OXA) encapsulated in a metal–organic framework (MOF) nanoparticle core and a dense shell of PD-L1 aptamer (denoted as M@O-A), as reported by Zhengyu Jin, Jie Tian, Yang Du, and co-workers in their Research Article (e202214750). Upon light irradiation, the versatile M@O-A allows for robust photo-immunotherapy against cancer by combining photodynamic therapy, chemotherapy, and immunotherapy in one nanoplatform with reduced immunotoxicity.
Knowledge gradient is a design principle for developing Bayesian sequential sampling policies to solve optimization problems. In this paper we consider the ranking and selection problem in the presence of covariates, ...
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Physicians use biopsies to distinguish between different but histologically similar enteropathies. The range of syndromes and pathologies that could cause different gastrointestinal conditions makes this a difficult p...
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This work deals with the hardware implementation of the Consultative Committee for Space datasystems File Delivery Protocol, using Consultative Committee for Space datasystems Packet Service and Telemetry/Telecomman...
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Our ability to generate new distributions of light has been remarkably enhanced in recent years. At the most fundamental level, these light patterns are obtained by ingeniously combining different electromagnetic mode...
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We developed a new way to engineer complex proteins toward multidimensional specifications using a simple, yet scalable, directed evolution strategy. By robotically picking mammalian cells that were identified, under ...
We developed a new way to engineer complex proteins toward multidimensional specifications using a simple, yet scalable, directed evolution strategy. By robotically picking mammalian cells that were identified, under a microscope, as expressing proteins that simultaneously exhibit several specific properties, we can screen hundreds of thousands of proteins in a library in just a few hours, evaluating each along multiple performance axes. To demonstrate the power of this approach, we created a genetically encoded fluorescent voltage indicator, simultaneously optimizing its brightness and membrane localization using our microscopy-guided cell-picking strategy. We produced the high-performance opsin-based fluorescent voltage reporter Archon1 and demonstrated its utility by imaging spiking and millivolt-scale subthreshold and synaptic activity in acute mouse brain slices and in larval zebrafish in vivo. We also measured postsynaptic responses downstream of optogenetically controlled neurons in C. elegans.
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