The Athena X-ray Observatory: Community Support Portal

  • Athena: revealing the Hot and Energetic Universe

    Athena: revealing the Hot and Energetic Universe

  • Where are the hot baryons and how do they evolve?

  • Reveal the causes and effects of cosmic feedback

  • Track obscured accretion through the epoch of galaxy formation

  • Understand the physics of accretion onto compact objects

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Athena papers

"Measuring turbulence and gas motions in galaxy clusters via synthetic Athena X-IFU observations", by M. Roncarelli et al.



The X-IFU that will be on board of Athena will allow a major breakthrough in our understanding of the physics of galaxy clusters. Besides thermodynamics quantities, such as density and temperature, that are already measurable by current X-ray instruments, the X-IFU will unveil the kinematics of the intracluster medium, mapping gas velocity and velocity dispersion by studying the emission lines of heavy elements. 

In this work, it is simulated a set of realistic X-IFU observation of galaxy clusters with the injection of turbulent motions, to test the accuracy of the X-IFU to recover and map their internal kinematics. It is shown that the X-IFU will be able to map kinematic quantities with great accuracy. This will open the possibility not only to measure intracluster turbulence but also to observe galaxy clusters rotation and the accretion of matter from the large-scale structure of the Universe with unprecedented detail.

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"The Performance of the Athena X-ray Integral Field Unit at Very High Count Rates", by P. Peille

Peille XIFU JLTPAbstract: "The Athena X-ray Integral Field Unit (X-IFU) will operate at 90 mK a hexagonal matrix of 3840 Transition Edge Sensor pixels providing spatially resolved high-resolution spectroscopy (2.5 eV FWHM up to 7 keV) between 0.2 and 12 keV. During the observation of very bright X-ray sources, the X-IFU detectors will receive high photon rates going up to several tens of counts per second per pixel and hundreds per readout channel, well above the normal operating mode of the instrument. In this paper, we investigate through detailed end-to-end simulations the performance achieved by the X-IFU at the highest count rates. Special care is notably taken to model and characterize pulse processing limitations, readout-chain saturation effects, as well as the non-Gaussian degradation of the energy redistribution from crosstalk at the focal plane level (both thermal and electrical). Overall, we show that the instrument performance should safely exceed the scientific requirements, and in particular that more than 50 % throughput at 1 Crab in the 5–8 keV band can be achieved with better than 10 eV average resolution with the use of a Beryllium filter, enabling breakthrough science in the field of bright sources."

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"Multi-parameter Nonlinear Gain Correction of X-ray Transition Edge Sensors for the X-ray Integral Field Unit", by E. Cucchetti

180427ECucchettiAbstract: "With its array of 3840 Transition Edge Sensors (TESs), the Athena X-ray Integral Field Unit (X-IFU) will provide spatially resolved high-resolution spectroscopy (2.5 eV up to 7 keV) from 0.2 to 12 keV, with an absolute energy scale accuracy of 0.4 eV. Slight changes in the TES operating environment can cause significant variations in its energy response function, which may result in systematic errors in the absolute energy scale. We plan to monitor such changes at pixel level via onboard X-ray calibration sources and correct the energy scale accordingly using a linear or quadratic interpolation of gain curves obtained during ground calibration. However, this may not be sufficient to meet the 0.4 eV accuracy required for the X-IFU. In this contribution, we introduce a new two-parameter gain correction technique, based on both the pulse-height estimate of a fiducial line and the baseline value of the pixels. Using gain functions that simulate ground calibration data, we show that this technique can accurately correct deviations in detector gain due to changes in TES operating conditions such as heat sink temperature, bias voltage, thermal radiation loading and linear amplifier gain. We also address potential optimisations of the onboard calibration source and compare the performance of this new technique with those previously used."

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"Chasing the observational signatures of seed black holes at z greater than 7: candidate observability", by R. Valiante et al

ChasingTheObservationalAbstract: "Observing the light emitted by the first accreting black holes (BHs) would dramatically improve our understanding of the formation of quasars at z > 6, possibly unveiling the nature of their supermassive black hole (SMBH) seeds. In previous works we explored the relative role of the two main competing BH seed formation channels, Population III remnants (low-mass seeds) and direct collapse BHs (high-mass seeds), investigating the properties of their host galaxies in a cosmological context. Building on this analysis, we predict here the spectral energy distribution and observational features of low- and high-mass BH seeds selected among the progenitors of a z~6 SMBH. We derive the processed emission from both accreting BHs and stars by using the photo-ionization code Cloudy, accounting for the evolution of metallicity and dust-to-gas mass ratio in the interstellar medium of the host galaxies, as predicted by the cosmological data- constrained model GAMETE/QSOdust. We show how future missions like JWST and ATHENA will be able to detect the light coming from SMBH progenitors already at z~16. We build upon previous complementary studies and propose a method based on the combined analysis of near infrared (NIR) colors, IR excess (IRX) and UV continuum slopes (i.e. color-color and IRX-Beta diagrams) to distinguish growing seed BH host galaxies from starburst-dominated systems in JWST surveys. Sources selected through this criterion would be the best target for follow-up X-ray observations."

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Advanced Telescope for High Energy Astrophysics


Athena (Advanced Telescope for High ENergy Astrophysics) is the X-ray observatory mission selected by ESA, within its Cosmic Vision 2015-2025 programme, to address the Hot and Energetic Universe scientific theme. It is the second L(large)-class mission within that programme and is due for launch in early 2030s.

Athena will study how hot baryons assemble into groups and clusters of galaxies, determine their chemical enrichment across cosmic time, measure their mechanical energy and characterise the missing baryons which are expected to reside in intergalactic filamentary structures. At the same time, it will study the physics of accretion into compact objects, find the earliest accreting supermassive black holes and trace their growth even when in very obscured environment, and show how they influence the evolution of galaxies and clusters through feedback processes. Athena will also have a fast target of opportunity observational capability, enabling studies and usage of GRBs and other transient phenomena. As an observatory, Athena will offer vital information on high-energy phenomena on all classes of astrophysical objects, from solar system bodies to the most distant objects known. See Science chapter for more details.

Athena will consist of a single large-aperture grazing-incidence X-ray telescope, utilizing a novel technology (High-performance Si pore optics) developed in Europe, with 12m focal length and 5 arcsec HEW on-axis angular resolution. The focal plane contains two instruments. One is the Wide Field Imager (WFI) providing sensitive wide field imaging and spectroscopy and high count-rate capability. The other one is the X-ray Integral Field Unit (X-IFU) delivering spatially resolved high-resolution X-ray spectroscopy over a limited field of view. See Mission chapter for more details.

With its unparalleled capabilities, Athena will be a truly transformational observatory, operating in conjunction with other large observatories across the electromagnetic spectrum available in the late 2020s (like ALMA, ELT, JWST, SKA, CTA, etc).