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19922026
Showing 2023 · astro-ph.HEShow all

40 papers · 2 filters

astro-ph.HE2023★ 27 cited

X-Ray Polarized View on the Accretion Geometry in the X-Ray Binary Circinus X-1

John Rankin, Fabio La Monaca, Alessandro Di Marco +101

Cir X-1 is a neutron star X-ray binary characterized by strong variations in flux during its eccentric 16.6 days orbit. There are also strong variations in the spectral state…

astro-ph.HE2023★ 93 cited

First M87 Event Horizon Telescope Results. IX. Detection of Near-horizon Circular Polarization

The Event Horizon Telescope Collaboration

Event Horizon Telescope (EHT) observations have revealed a bright ring of emission around the supermassive black hole at the center of the M87 galaxy. EHT images in linear polariza…

astro-ph.HE2023★ 12 cited

Polarimetric Geometric Modeling for mm-VLBI Observations of Black Holes

Freek Roelofs, Michael D. Johnson, Andrew Chael +4

The Event Horizon Telescope (EHT) is a millimeter very long baseline interferometry (VLBI) array that has imaged the apparent shadows of the supermassive black holes M87* and Sagit…

astro-ph.HE2023★ 681 cited

First Sagittarius A* Event Horizon Telescope Results. VI: Testing the Black Hole Metric

The Event Horizon Telescope Collaboration

Astrophysical black holes are expected to be described by the Kerr metric. This is the only stationary, vacuum, axisymmetric metric, without electromagnetic charge, that satisfies…

astro-ph.HE2023★ 450 cited

First Sagittarius A* Event Horizon Telescope Results. III: Imaging of the Galactic Center Supermassive Black Hole

The Event Horizon Telescope Collaboration

We present the first event-horizon-scale images and spatiotemporal analysis of Sgr A* taken with the Event Horizon Telescope in 2017 April at a wavelength of 1.3 mm. Imaging of Sgr…

astro-ph.HE2023★ 548 cited

First Sagittarius A* Event Horizon Telescope Results. V. Testing Astrophysical Models of the Galactic Center Black Hole

The Event Horizon Telescope Collaboration

In this paper, we provide a first physical interpretation for the Event Horizon Telescope (EHT)'s 2017 observations of Sgr A*. Our main approach is to compare resolved EHT data at…

astro-ph.HE2023★ 1.9k cited

First Sagittarius A* Event Horizon Telescope Results. I. The Shadow of the Supermassive Black Hole in the Center of the Milky Way

The Event Horizon Telescope Collaboration

We present the first Event Horizon Telescope (EHT) observations of Sagittarius A* (Sgr A), the Galactic center source associated with a supermassive black hole. These observati…

astro-ph.HE2023★ 370 cited

First Sagittarius A* Event Horizon Telescope Results. IV. Variability, Morphology, and Black Hole Mass

The Event Horizon Telescope Collaboration

In this paper we quantify the temporal variability and image morphology of the horizon-scale emission from Sgr A*, as observed by the EHT in 2017 April at a wavelength of 1.3 mm. W…

astro-ph.HE2023★ 376 cited

First Sagittarius A* Event Horizon Telescope Results. II. EHT and Multi-wavelength Observations, Data Processing, and Calibration

The Event Horizon Telescope Collaboration

We present Event Horizon Telescope (EHT) 1.3 mm measurements of the radio source located at the position of the supermassive black hole Sagittarius A* (Sgr A*), collected during th…

astro-ph.HE2023★ 39 cited

Highly Significant Detection of X-Ray Polarization from the Brightest Accreting Neutron Star Sco X-1

Fabio La Monaca, Alessandro Di Marco, Juri Poutanen +116

The Imaging X-ray Polarimetry Explorer (IXPE) measured with high significance the X-ray polarization of the brightest Z-source Scorpius X-1, resulting in the nominal 2-8 keV energy…

astro-ph.HE2023★ 4 cited

Searches for neutrino counterparts of gravitational waves from the LIGO/Virgo third observing run with KM3NeT

KM3NeT Collaboration, S. Aiello, A. Albert +273

The KM3NeT neutrino telescope is currently being deployed at two different sites in the Mediterranean Sea. First searches for astrophysical neutrinos have been performed using data…

astro-ph.HE2023★ 2 cited

Galactic Gamma-Ray Diffuse Emission at TeV energies with HAWC Data

R. Alfaro, C. Alvarez, J. C. Arteaga-Velazquez +77

The Galactic gamma-ray diffuse emission (GDE) is emitted by cosmic rays (CRs), ultra-relativistic protons and electrons, interacting with gas and electromagnetic radiation fields i…

astro-ph.HE2023★ 23 cited

Radio Measurements of the Depth of Air-Shower Maximum at the Pierre Auger Observatory

The Pierre Auger Collaboration, A. Abdul Halim, P. Abreu +372

The Auger Engineering Radio Array (AERA), part of the Pierre Auger Observatory, is currently the largest array of radio antenna stations deployed for the detection of cosmic rays,…

astro-ph.HE2023★ 19 cited

Demonstrating Agreement between Radio and Fluorescence Measurements of the Depth of Maximum of Extensive Air Showers at the Pierre Auger Observatory

The Pierre Auger Collaboration, A. Abdul Halim, P. Abreu +372

We show, for the first time, radio measurements of the depth of shower maximum () of air showers induced by cosmic rays that are compared to measurements of the estab…

astro-ph.HE2023★ 26 cited

First X-ray polarization measurement confirms the low black-hole spin in LMC X-3

Jiří Svoboda, Michal Dovčiak, James F. Steiner +109

X-ray polarization is a powerful tool to investigate the geometry of accreting material around black holes, allowing independent measurements of the black hole spin and orientation…

astro-ph.HE2023★ 16 cited

Searches for neutrinos in the direction of radio-bright blazars with the ANTARES telescope

ANTARES Collaboration, A. Albert, S. Alves +162

Active galaxies, especially blazars, are among the most promising neutrino source candidates. To date, ANTARES searches for these objects considered GeV-TeV -ray bright blazars.…

astro-ph.HE2023★ 4 cited

The Pierre Auger Observatory Open Data

The Pierre Auger Collaboration, A. Abdul Halim, P. Abreu +358

The Pierre Auger Collaboration has embraced the concept of open access to their research data since its foundation, with the aim of giving access to the widest possible community.…

astro-ph.HE2023★ 5 cited

Prospects for combined analyses of hadronic emission from -ray sources in the Milky Way with CTA and KM3NeT

T. Unbehaun, L. Mohrmann, S. Funk +271

The Cherenkov Telescope Array and the KM3NeT neutrino telescopes are major upcoming facilities in the fields of -ray and neutrino astronomy, respectively. Possible simultaneous…

astro-ph.HE2023★ 6 cited

Search for UHE Photons from Gravitational Wave Sources with the Pierre Auger Observatory

The Pierre Auger Collaboration, A. Abdul Halim, P. Abreu +368

A search for time-directional coincidences of ultra-high-energy (UHE) photons above 10 EeV with gravitational wave (GW) events from the LIGO/Virgo runs O1 to O3 is conducted with t…

astro-ph.HE2023★ 50 cited

Observations of the Crab Nebula and Pulsar with the Large-Sized Telescope Prototype of the Cherenkov Telescope Array

CTA-LST Project, :, H. Abe +289

CTA (Cherenkov Telescope Array) is the next generation ground-based observatory for gamma-ray astronomy at very-high energies. The Large-Sized Telescope prototype (LST-1) is locate…

astro-ph.HE2023★ 45 cited

X-ray polarimetry and spectroscopy of the neutron star low-mass X-ray binary GX 9+9: an in-depth study with IXPE and NuSTAR

F. Ursini, R. Farinelli, A. Gnarini +101

We report on a comprehensive analysis of simultaneous X-ray polarimetric and spectral data of the bright atoll source GX 9+9 with the Imaging X-ray Polarimetry Explorer (IXPE) and…

astro-ph.HE2023★ 14 cited

Galactic Diffuse Neutrino Emission from Sources beyond the Discovery Horizon

Antonio Ambrosone, Kathrine Mørch Groth, Enrico Peretti +1

The IceCube Neutrino Observatory has recently reported strong evidence for neutrino emission from the Galactic plane. The signal is consistent with model predictions of diffuse emi…

astro-ph.HE2023★ 36 cited

First detection of X-ray polarization from the accreting neutron star 4U 1820-303

Alessandro Di Marco, Fabio La Monaca, Juri Poutanen +116

This paper reports the first detection of polarization in the X-rays for atoll-source 4U 1820-303, obtained with the Imaging X-ray Polarimetry Explorer (IXPE) at 99.999% confidence…

astro-ph.HE2023★ 29 cited

Complex variations of X-ray polarization in the X-ray pulsar LS V +44 17/RX J0440.9+4431

Victor Doroshenko, Juri Poutanen, Jeremy Heyl +109

We report on Imaging X-ray polarimetry explorer (IXPE) observations of the Be-transient X-ray pulsar LS V +44 17/RX J0440.9+4431 made at two luminosity levels during the giant outb…