Searcharxiv⌕ Search
Home/Archive/arXiv

arXiv · 2211.09827

Line Emission Mapper (LEM): Probing the physics of cosmic ecosystems

Ralph Kraft·Maxim Markevitch·Caroline Kilbourne·Joseph S. Adams·Hiroki Akamatsu·Mohammadreza Ayromlou·Simon R. Bandler·Marco Barbera·Douglas A. Bennett·Anil Bhardwaj·Veronica Biffi·Dennis Bodewits·Akos Bogdan·Massimiliano Bonamente·Stefano Borgani·Graziella Branduardi-Raymont·Joel N. Bregman·Joseph N. Burchett·Jenna Cann·Jenny Carter·Priyanka Chakraborty·Eugene Churazov·Robert A. Crain·Renata Cumbee·Romeel Dave·Michael DiPirro·Klaus Dolag·W. Bertrand Doriese·Jeremy Drake·William Dunn·Megan Eckart·Dominique Eckert·Stefano Ettori·William Forman·Massimiliano Galeazzi·Amy Gall·Efrain Gatuzz·Natalie Hell·Edmund Hodges-Kluck·Caitriona Jackman·Amir Jahromi·Fred Jennings·Christine Jones·Philip Kaaret·Patrick J. Kavanagh·Richard L. Kelley·Ildar Khabibullin·Chang-Goo Kim·Dimitra Koutroumpa·Orsolya Kovacs·K. D. Kuntz·Erwin Lau·Shiu-Hang Lee·Maurice Leutenegger·Sheng-Chieh Lin·Carey Lisse·Ugo Lo Cicero·Lorenzo Lovisari·Dan McCammon·Sean McEntee·Francois Mernier·Eric D. Miller·Daisuke Nagai·Michela Negro·Dylan Nelson·Jan-Uwe Ness·Paul Nulsen·Anna Ogorzalek·Benjamin D. Oppenheimer·Lidia Oskinova·Daniel Patnaude·Ryan W. Pfeifle·Annalisa Pillepich·Paul Plucinsky·David Pooley·Frederick S. Porter·Scott Randall·Elena Rasia·John Raymond·Mateusz Ruszkowski·Kazuhiro Sakai·Arnab Sarkar·Manami Sasaki·Kosuke Sato·Gerrit Schellenberger·Joop Schaye·Aurora Simionescu·Stephen J. Smith·James F. Steiner·Jonathan Stern·Yuanyuan Su·Ming Sun·Grant Tremblay·Nhut Truong·James Tutt·Eugenio Ursino·Sylvain Veilleux·Alexey Vikhlinin·Stephan Vladutescu-Zopp·Mark Vogelsberger
View original source ↗Read source document ↗Export metadata ↓

Abstract

The Line Emission Mapper (LEM) is an X-ray Probe for the 2030s that will answer the outstanding questions of the Universe's structure formation. It will also provide transformative new observing capabilities for every area of astrophysics, and to heliophysics and planetary physics as well. LEM's main goal is a comprehensive look at the physics of galaxy formation, including stellar and black-hole feedback and flows of baryonic matter into and out of galaxies. These processes are best studied in X-rays, and emission-line mapping is the pressing need in this area. LEM will use a large microcalorimeter array/IFU, covering a 30x30' field with 10" angular resolution, to map the soft X-ray line emission from objects that constitute galactic ecosystems. These include supernova remnants, star-forming regions, superbubbles, galactic outflows (such as the Fermi/eROSITA bubbles in the Milky Way and their analogs in other galaxies), the Circumgalactic Medium in the Milky Way and other galaxies, and the Intergalactic Medium at the outskirts and beyond the confines of galaxies and clusters. LEM's 1-2 eV spectral resolution in the 0.2-2 keV band will make it possible to disentangle the faintest emission lines in those objects from the bright Milky Way foreground, providing groundbreaking measurements of the physics of these plasmas, from temperatures, densities, chemical composition to gas dynamics. While LEM's main focus is on galaxy formation, it will provide transformative capability for all classes of astrophysical objects, from the Earth's magnetosphere, planets and comets to the interstellar medium and X-ray binaries in nearby galaxies, AGN, and cooling gas in galaxy clusters. In addition to pointed observations, LEM will perform a shallow all-sky survey that will dramatically expand the discovery space.

Explore related subjects

astro-ph.IMastro-ph.GAastro-ph.HE

Keep this discovery

BibTeXRIS

Ralph Kraft, Maxim Markevitch, Caroline Kilbourne, Joseph S. Adams, Hiroki Akamatsu, Mohammadreza Ayromlou, Simon R. Bandler, Marco Barbera, Douglas A. Bennett, Anil Bhardwaj, Veronica Biffi, Dennis Bodewits, Akos Bogdan, Massimiliano Bonamente, Stefano Borgani, Graziella Branduardi-Raymont, Joel N. Bregman, Joseph N. Burchett, Jenna Cann, Jenny Carter, Priyanka Chakraborty, Eugene Churazov, Robert A. Crain, Renata Cumbee, Romeel Dave, Michael DiPirro, Klaus Dolag, W. Bertrand Doriese, Jeremy Drake, William Dunn, Megan Eckart, Dominique Eckert, Stefano Ettori, William Forman, Massimiliano Galeazzi, Amy Gall, Efrain Gatuzz, Natalie Hell, Edmund Hodges-Kluck, Caitriona Jackman, Amir Jahromi, Fred Jennings, Christine Jones, Philip Kaaret, Patrick J. Kavanagh, Richard L. Kelley, Ildar Khabibullin, Chang-Goo Kim, Dimitra Koutroumpa, Orsolya Kovacs, K. D. Kuntz, Erwin Lau, Shiu-Hang Lee, Maurice Leutenegger, Sheng-Chieh Lin, Carey Lisse, Ugo Lo Cicero, Lorenzo Lovisari, Dan McCammon, Sean McEntee, Francois Mernier, Eric D. Miller, Daisuke Nagai, Michela Negro, Dylan Nelson, Jan-Uwe Ness, Paul Nulsen, Anna Ogorzalek, Benjamin D. Oppenheimer, Lidia Oskinova, Daniel Patnaude, Ryan W. Pfeifle, Annalisa Pillepich, Paul Plucinsky, David Pooley, Frederick S. Porter, Scott Randall, Elena Rasia, John Raymond, Mateusz Ruszkowski, Kazuhiro Sakai, Arnab Sarkar, Manami Sasaki, Kosuke Sato, Gerrit Schellenberger, Joop Schaye, Aurora Simionescu, Stephen J. Smith, James F. Steiner, Jonathan Stern, Yuanyuan Su, Ming Sun, Grant Tremblay, Nhut Truong, James Tutt, Eugenio Ursino, Sylvain Veilleux, Alexey Vikhlinin, Stephan Vladutescu-Zopp, Mark Vogelsberger. 2022-11-17. Line Emission Mapper (LEM): Probing the physics of cosmic ecosystems. https://arxiv.org/abs/2211.09827

Cite the original work for its findings. Save a collection to share your selection of sources.

KEEP EXPLORING

Related papers

arXiv2026

The EDD Radio Astronomy Backend Framework

Modern digital radio astronomy receivers produce increasingly wide-bandwidth, high bit-rate data streams that necessitate the development of flexible, scalable, and maintainable backend processing and recording systems. Historically, such backend instrumentation has been tightly coupled to telescope observing modes, limiting reuse between observatories and science cases. We present the Effelsberg Direct Digitisation (EDD) backend framework, a software-defined architecture for constructing real-time radio astronomy backends on commodity off-the-shelf computing infrastructure. We describe its design, implementation, supported observing modes, and operational deployments. EDD separates a common core framework from plugin-provided observing capabilities. The core provides orchestration, telescope interfaces, pipeline lifecycle management, monitoring, and deployment tooling, while plugins implement processing pipelines for specific observing modes. The framework is designed to support both single-dish and interferometric instruments through site-specific configuration and plugin selection. EDD currently supports spectroscopy and spectropolarimetry, pulsar timing and searching, baseband recording, very long baseline interferometry, correlation, and beamforming. Operational deployments include the Effelsberg 100-m telescope, the SKA-MPI prototype dish, the Thai National Radio Telescope, and the ARGOS interferometric prototype array. By separating common services, observing-mode plugins, and site-specific configuration, it allows backend capabilities to be deployed across heterogeneous telescope environments and provides a community resource for broadband radio astronomy instrumentation.

astro-ph.IM↗
arXiv2026

Bayesian Superiority in On/Off analysis

We present a detailed comparison of Bayesian criteria with three non-informative priors - flat, Jeffreys, and scale-invariant - for testing a signal against an unknown background and compare them with the classical frequentist Li-Ma approach in the On/Off problem. We perform Monte Carlo simulations for various background levels and evaluate the Li-Ma and Bayesian criteria by their Type I error rates. We then simulate a nonzero signal and compare the criteria in terms of Type II error rates. We find that the Bayesian criterion with the Jeffreys prior yields lower Type I and Type II error rates than the Li-Ma criterion. In addition, we show that the Bayesian criteria are more robust than the Li-Ma criterion when the background distribution is overdispersed relative to the Poisson distribution.

astro-ph.IM↗
arXiv2026

An RFSoC-based Backend and Timing System for the Balloon-borne Very Long Baseline Interferometry Experiment

We present the design and performance characterization of the digital backend and precision-timing system for the Balloon-borne Very Long Baseline Interferometry Experiment (BVEX), a pathfinder for high-frequency stratospheric VLBI at 22 GHz. The backend uses one of the four 14-bit analog-to-digital converter inputs on an AMD-Xilinx RFSoC 4x2. Although the converters support sampling rates up to 5 GSPS, the flight configuration digitizes the 2-4 GHz intermediate frequency at 4.096 GSPS. CASPER firmware provides both a high-resolution spectrometer for pointing and receiver verification, and a VLBI acquisition chain with two-bit requantization that records at a rate of about 8.2 Gbps. The timestamped data packets are sent over 100 Gigabit Ethernet (GbE) to a 16 TB NVMe array in a storage computer that draws approximately 70-80 W. The timing chain uses a Rakon oven-controlled crystal oscillator as a timing reference while a time-interval counter measures its drift relative to a GPS reference with approximately 60 ps resolution. This is the first deployment of an RFSoC-based VLBI backend and precision-timing system on a stratospheric balloon. Ground tests validated the backend, spectrometer, and timing chain. The August 2025 CSA STRATOS flight ended before reaching the target float altitude because of a balloon failure, and as a result no science observations were obtained. For the planned 2027 reflight, we are developing a conduction-cooled data storage computer with 24 TB of NVMe capacity and a direct data path from the 100 GbE interface to the NVMe array.

astro-ph.IM↗