es/iode’s Post

📃Scientific paper: Modelling magnetically formed neutron star mountains Abstract: With the onset of the era of gravitational-wave (GW) astronomy, the search for continuous gravitational waves (CGWs), which remain undetected to date, has intensified in more ways than one. Rapidly rotating neutron stars with non-axisymmetrical deformations are the main targets for CGW searches. The extent of this quadrupolar deformation is measured by the maximum ellipticity that can be sustained by the crust of a neutron star and it places an upper limit on the CGW amplitudes emitted by such systems. In this paper, following previous works on this subject, we calculate the maximum ellipticity of a neutron star generated by the Lorentz force exerted on it by the internal magnetic fields. We show that the ellipticity of stars deformed by such a Lorentz force is of the same order of magnitude as previous theoretical and astrophysical constraints. We also consider if this ellipticity can be further enhanced by crustal surface currents. We discover that this is indeed true; surface currents at crustal boundaries are instrumental towards enhancing the ellipticity of magnetized neutron stars. ;Comment: 17 pages, 15 figures Continued on ES/IODE ➡️ https://etcse.fr/cXfgo ------- If you find this interesting, feel free to follow, comment and share. We need your help to enhance our visibility, so that our platform continues to serve you.

My first paper is now available on arXiv. It presents the results obtained in my Master's thesis. Title: Superradiance of charged black holes embedded in dark matter halos. Abstract:Astrophysical environments are ubiquitous in the Universe; from accretion disks around black holes to galactic dark matter halos, distributions of astrophysical material veil the vast majority of Cosmos. Including environmental effects in strong-field gravity and astrophysics is, therefore, a rather tantalizing task in the quest for novel gravitational-wave phenomena. Here, we examine how environments affect the high-energy process of superradiance. In particular, we study the amplification of charged scalar waves under the expense of the electrostatic energy contained in a charged black hole that is embedded in an observationally-motivated, and qualitatively generic, dark matter halo. We find that the superradiant amplification of massless charged scalar fields scattering off environmentally-enriched charged black holes can be equally efficient to those occurring in vacuum charged black holes. This occurs due to the fact that the sole interplay between the scalar wave and the black hole is the electromagnetic interaction. The addition of mass on the charged scalar waves leads to a rapid suppression of superradiant amplification. This transpires to a great extent due to the `friction' that the mass introduces to the black hole potential. Nevertheless, for sufficiently large scalar masses, the amplification factors can be also subdominantly affected by the compactness of the halo. This occurs because the gravitational interaction between the dense halo and the wave's mass grows, thus further suppressing the superradiant amplification. https://lnkd.in/e9VjaA6Y

Off to the stars: We recently welcomed representatives of the planned Deutsches Zentrum für Astrophysik (DZA) at Fraunhofer ENAS in Chemnitz.   The new large-scale astrophysical research center is to be built in the Lausitz area in Saxony and will uncover groundbreaking and exciting phenomena in astronomy and astrophysics through the observation of our cosmos. This will help to further improve our knowledge and understanding of our universe.   In an open and inspiring exchange with our colleagues, we were able to gain exciting insights into the planned DZA and explore opportunities for joint, future collaboration in space research and the processing of huge amounts of data with the help of clever sensor technologies and AI-supported models.    We would like to take this opportunity to express our sincere thanks for the trusting dialogue and the interest in our smart technologies. We are keeping our fingers crossed for the DZA and the further development phase and are already excited to see what pioneering findings about our celestial bodies the DZA will reveal!   Our thanks for the pleasant conversations and the fruitful exchange go to: Prof. Günther Hasinger I Prof. Jürgen Besold I Prof. Martin M. Roth I Prof. Hermann Heßling I Prof. Harald Kuhn I Prof. Stefan E. Schulz I Dr. Alexander Weiß I Dr. Roman Forke I Dr. Stefanie Diana Zimmermann.   #Space #Astronomy #Astrophysics #Galaxy #Universe #Cosmos #Research #Collaboration #Sensor #Sensors #AI #DZA

#Prize 🏆 Congratulations to Thomas Dauser, research scientist in X-ray astronomy at FAU Faculty of Sciences & member of the X-IFU Consortium, who receives the 2024 HEAD Innovation Prize from the American Astronomical Society (AAS).   ▶ This prestigious prize is awarded by HEAD approximately every 18 months to recognize the development of innovative, fundamental or revolutionary instrumentation or software that has led to breakthrough results in high-energy #astrophysics. This year, it rewards the development of novel models to describe the radiation from very high gravity regions of accreting compact objects such as black holes and neutron stars.   ▶ As for the X-IFU specifically, this model describes relativistic reflection of hard X-rays at the inner accretion disk in strong gravity close to black holes. The X-IFU will routinely perform such measurements at a much shorter exposure than previously possible and the micro-calorimeter energy resolution will improve the constraints of these parameters. For further information: 🔗 https://lnkd.in/ewRrZtEy 🔗 https://lnkd.in/eiFDDCiE #Science #Astronomy #Research

📃Scientific paper: From Active Stars to Black Holes: A Tool for the SRG/eROSITA X-ray Survey and New Discoveries as Proof of Concept Abstract: Galactic X-ray sources are diverse, ranging from active M dwarfs to compact object binaries, and everything in between. The X-ray landscape of today is rich, with point source catalogs such as those from XMM-Newton, Chandra, and Swift, each with $\gtrsim10^5$ sources and growing. Furthermore, X-ray astronomy is on the verge of being transformed through data releases from the all-sky SRG/eROSITA survey. Many X-ray sources can be associated with an optical counterpart, which in the era of Gaia, can be determined to be Galactic or extragalactic through parallax and proper motion information. Here, I present a simple diagram -- the ``X-ray Main Sequence", which distinguishes between compact objects and active stars based on their optical color and X-ray-to-optical flux ratio \($F\_X/F\_\textrm\{opt\}$\). As a proof of concept, I present optical spectroscopy of six exotic accreting WDs discovered using the X-ray Main Sequence as applied to the XMM-Newton catalog. Looking ahead to surveys of the near future, I additionally present SDSS-V optical spectroscopy of new systems discovered using the X-ray Main Sequence as applied to the SRG/eROSITA eFEDS catalog. ;Comment: Submitted to PASP Continued on ES/IODE ➡️ https://etcse.fr/JaVA5 ------- If you find this interesting, feel free to follow, comment and share. We need your help to enhance our visibility, so that our platform continues to serve you.

Hello LinkedIn community! I am pleased to present my latest results: a comprehensive review of research that sheds new light on one of astronomy's greatest mysteries: the dark side. 🌌 Revolutionary Insights: My research explores the fascinating world of dark matter, from sterile neutrinos to mysterious axions, the mysteries of space, black, and the possibility of the fifth. I delved into the theoretical aspects of Massively Compact Halo Objects (MACHOs) and Weakly Interacting Massive Particles (WIMPs) to understand their unique roles in the cosmic fabric. 🧊🔥 Dark Matter Classification: This analysis further divides dark matter into cold (CDM), hot (HDM), and hot (WDM), each of which exhibit unique properties and impact our understanding of the universe. 🔭 Observational Evidence: Consensual evidence forms the basis of this study. I learned to describe signs of the existence of dark matter, from the strangeness of galaxy rotation curves to gravitational lensing phenomena and cosmic microwave background radiation (CMBR). Debate continues over information obtained from Type I supernova observations, sky surveys, baryon acoustic oscillations, redshift space distortions, and complex Lyman-alpha forests. 🤝 Collaborative Victory: This would not have been possible without the collaboration of the astrophysics community. Special thanks to Astro Roxy for her invaluable guidance and guidance during this challenging journey. 🚀 Join the Odyssey: As we stand on the threshold of new astronomical discoveries, I invite you to this review content. Let's discuss and share understanding; What do you think about these dark topics that facilitate our journey around the world? #DarkMatter #Astrophysics #ResearchReview #Astronomy #ScienceCommunication #SpaceExploration

📃Scientific paper: From Active Stars to Black Holes: A Tool for the SRG/eROSITA X-ray Survey and New Discoveries as Proof of Concept Abstract: Galactic X-ray sources are diverse, ranging from active M dwarfs to compact object binaries, and everything in between. The X-ray landscape of today is rich, with point source catalogs such as those from XMM-Newton, Chandra, and Swift, each with $\gtrsim10^5$ sources and growing. Furthermore, X-ray astronomy is on the verge of being transformed through data releases from the all-sky SRG/eROSITA survey. Many X-ray sources can be associated with an optical counterpart, which in the era of Gaia, can be determined to be Galactic or extragalactic through parallax and proper motion information. Here, I present a simple diagram -- the ``X-ray Main Sequence", which distinguishes between compact objects and active stars based on their optical color and X-ray-to-optical flux ratio \($F\_X/F\_\textrm\{opt\}$\). As a proof of concept, I present optical spectroscopy of six exotic accreting WDs discovered using the X-ray Main Sequence as applied to the XMM-Newton catalog. Looking ahead to surveys of the near future, I additionally present SDSS-V optical spectroscopy of new systems discovered using the X-ray Main Sequence as applied to the SRG/eROSITA eFEDS catalog. ;Comment: Submitted to PASP Continued on ES/IODE ➡️ https://etcse.fr/JaVA5 ------- If you find this interesting, feel free to follow, comment and share. We need your help to enhance our visibility, so that our platform continues to serve you.

📃Scientific paper: The hunt of PeVatrons as the origin of the most energetic photons observed in our Galaxy Abstract: Ultrarelativistic particles called cosmic rays permeate the Milky Way, propagating through the Galactic turbulent magnetic fields. The mechanisms under which these particles increase their energy can be reasonably described by current theories of acceleration and propagation of cosmic rays. There are, however, still many open questions as to how to reach petaelectronvolt \(PeV\) energies, the maximum energy believed to be attained in our Galaxy, and in which astrophysical sources \(dubbed \{\it PeVatrons\}\) this ultra-high energy acceleration happens. In this article, we describe the theoretical conditions for plasma acceleration to these energies, and the Galactic sources in which these conditions are possible. These theoretical predictions are then confronted with the latest experimental results, summarising the state-of-the-art of our current knowledge of PeVatrons. We finally describe the prospects to keep advancing the understanding of these elusive objects, still unidentified more than one hundred years after the discovery of cosmic rays. ;Comment: Published in Nature Astronomy, Volume 8, pages 425-431 \(2024\) Continued on ES/IODE ➡️ https://etcse.fr/9hV ------- If you find this interesting, feel free to follow, comment and share. We need your help to enhance our visibility, so that our platform continues to serve you.

A recent paper published by a team of Hopkins physicists and astronomers has permanently changed the landscape of the Cosmic Microwave... #astronomy #astrophysics #blackhole #cosmology #darkenergy #darkmatter #darkuniverse #physics #stringtheory

Karl Schwarzschild ( 1873 – 1916 ) was a German physicist and astronomer. Schwarzschild was a pioneering astrophysicist and mathematician known for his contributions in the fields of astronomy and theoretical physics. Some of his most significant contributions include: 1. Schwarzschild Solution to Einstein's Field Equations:   - Schwarzschild is best known for his solution to the Einstein field equations of general relativity, found just a few months after Einstein published his theory in 1915. The Schwarzschild solution describes the gravitational field outside a spherical mass such as a star or black hole, assuming the mass is not rotating. This solution led to the prediction of black holes, objects from which not even light can escape due to extreme gravitational forces. 2. Schwarzschild Radius:   - From his solution, Schwarzschild derived a critical radius now known as the Schwarzschild radius, which defines the size of the event horizon of a black hole. The concept is crucial for understanding black hole physics and the behavior of matter under extreme gravitational forces. 3. Advances in Astrophotography:   - Schwarzschild also made significant advances in astrophotography, developing techniques that improved the accuracy of astronomical observations. He worked on methods to reduce errors in photographic measurements of stars, contributing to more precise stellar photometry. 4. Stellar Structure and Atmospheres:   - He made contributions to our understanding of stellar atmospheres and the radiative transfer of energy within them. His work in this area laid the groundwork for future research in astrophysics, particularly in how light and energy move through stars. 5. Work on Celestial Mechanics:   - Schwarzschild contributed to celestial mechanics, including precise calculations of the orbits of celestial bodies. His work helped improve the accuracy of astronomical tables and the prediction of stellar and planetary positions. Schwarzschild’s work had a profound impact on the development of theoretical physics, particularly in our understanding of gravitational fields and the structure of the cosmos. His solutions and methodologies remain foundational in modern astrophysics and cosmology. https://lnkd.in/ejGPjdTz Source: Wiki, AIs and humans