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Abstract:

Abstract Recent work revealed the existence of a galaxy ‘millimetre fundamental plane of black hole accretion’, a tight correlation between nuclear 1 mm luminosity, intrinsic 2 – 10 keV X-ray luminosity and supermassive black hole mass, originally discovered for nearby low- and high-luminosity active galactic nuclei. Here we use mm and X-ray data of 5 X-ray binaries (XRBs) to demonstrate that these stellar-mass black holes also lie on the mm fundamental plane, as they do at radio wavelengths. One source for which we have multi-epoch observations shows evidence of deviations from the plane after a state change, suggesting that the plane only applies to XRBs in the hard state, as is true again at radio wavelengths. We show that both advection-dominated accretion flows and compact jet models predict the existence of the plane across the entire range of black hole masses, although these models vary in their ability to accurately predict the XRB black hole masses.

Abstract:

Abstract We present the first application of marked power spectra to weak lensing data, using maps from the Subaru Hyper Suprime-Cam Year 1 (HSC-Y1) survey. Marked convergence fields, constructed by weighting the convergence field with non-linear functions of its smoothed version, are designed to encode higher-order information while remaining computationally tractable. Using simulations tailored to the HSC-Y1 data, we test three mark functions that up- or down-weight different density environments. Our results show that combining multiple types of marked auto- and cross-spectra improves constraints on the clustering amplitude parameter $S_8\equiv \sigma _8\sqrt{\Omega _{\rm m}/0.3}$ by ≈43 percnt compared to standard two-point power spectra. When applied to the HSC-Y1 data, this translates into a constraint on S8 = 0.807 ± 0.024. We assess the sensitivity of the marked power spectra to systematics, including baryonic effects, intrinsic alignment, photometric redshifts, and multiplicative shear bias. We note that some of the additional information introduced by the marked field originates from scales smaller than the scale cut, and is partly Gaussian in nature. This does not invalidate our systematic tests. These results demonstrate the promise of marked statistics as a practical and powerful tool for extracting non-Gaussian information from weak lensing surveys.

Abstract:

Black holes (BHs) in microquasars can launch powerful relativistic jets that have the capacity to travel up to several parsecs from the compact object and interact with the interstellar medium. Recently, the detection of large-scale very-high-energy (VHE) gamma-ray emission around the black hole transient V4641 Sgr and other BH-jet systems suggested that jets from microquasars may play an important role in the production of galactic cosmic rays. V4641 Sgr is known for its superluminal radio jet discovered in 1999, but no radio counterpart of a large-scale jet has been observed. The goal of this work is to search for a radio counterpart of the extended VHE source. We observed V4641 Sgr with the MeerKAT radio telescope at the and bands and produced deep maps of the field using high dynamic range techniques. L UHF We report the discovery of a large-scale (∼ 35 ), bow-tie-shaped, diffuse, radio structure around V4641 Sgr, with similar angular size to the extended X-ray emission discovered by XRISM. However, it is not spatially coincident with the extended VHE emission. After discussing the association of the structure with V4641 Sgr, we investigate the nature of the emission mechanism. We suggest that the bow-tie structure arose from the long-term action of large-scale jets or disk winds from V4641 Sgr. If the emission mechanism is of synchrotron origin, the radio/X-ray extended structure implies acceleration of electrons up to more than 100 as far as tens of parsecs from the black hole. pc TeV