Logo

The Athena X-ray Observatory: Community Support Portal

This web portal uses third-party cookies to track visits to the website only, no personal information is collected.

By continuing to use the site you are agreeing to our use of cookies. Learn more

I understand

Use of cookies

This website uses Google Analytics, a web analytics service provided by Google, Inc. (“Google”). Google Analytics uses “cookies”, which are text files placed on your computer, to help the website analyze how users use the site. The information generated by the cookie about your use of the website (including your IP address) will be transmitted to and stored by Google on servers in the United States. The IP address will be truncated before transmission. On our behalf Google will use this information for the purpose of evaluating your use of the website, compiling reports on website activity and providing other services relating to website activity and internet activity in connection with the use of the website. Google will not associate your IP address with any other data held by Google.

If you do not wish to receive a cookie, or if you wish your browser to notify you when you receive a cookie, you may use the option on your web browser to disable cookies. Click on the 'help' section of your browser to learn how to change cookie preferences.

Papers related to Athena

Papers related to Athena

"X-ray absorption towards high-redshift sources: probing the intergalactic medium with blazars", by R. Arcodia

1804RArcodia et alAbstract: "The role played by the intergalactic medium (IGM) in the X-ray absorption towards high-redshift sources has recently drawn mo re attention in spectral analysis studies. Here, we study the X-r ay absorption towards 15 flat-spectrum radio quasars at z > 2, relying on high counting statistic (& 10 000 photons) provided by XMM-Newton, with additional NuSTAR (and simultaneous Swift-XRT) observations when available. Blazars can be confidently considered to have negligible X-ray absorption along the line of sight withinthe host galaxy, likely swept by the kpc-scale relativistic jet. This makes our sources ideal for testing the absorption component along the IGM. Our new approach is to revisit the origin of the soft X-ray spectral hardening observed in high-z blazars in terms of X-ray absorption occurring along the IGM, with the help of a low-z sample used as comparison. We verify that the presence of absorption in excess of the Galactic value is the preferred explanation to explain the observed hardening, while intrinsic energy breaks, predicted by blazars’ emission models, can easily occur out of the observing energy band in most sources. First, we perform an indirect analysis comparing the inferred amount of absorption in excess of the Galactic value with a simulated IGM absorption contribution, that increases with redshift and includes both a minimum component from diffuse IGM metals, and the additional contribution of discretedenser intervening regions. Then, we directly investigate the warm-hot IGM with a spectral model on the best candidates of our sample, obtaining an average IGM density of n0 = 1.01[+0.53,−0.72] × 10−7 cm−3 and temperature of log(T/K) = 6.45[+0.51−2.12]. A more dedicated study is currently beyond reach, but our results can be used as a stepping stone for future more accurate analysis, involving Athena."

Read full document.

"Order parameters for the high-energy spectra of pulsars", by Diego F. Torres

DiegoTorres Paper

Abstract: "From the hundreds of gamma-ray pulsars known, only a handful show non-thermal X-ray pulsations. Instead, nine objects pulse in non-thermal X-rays but lack counterparts at higher energies. Here, we present a physical model for the non-thermal emission of pulsars above 1 keV. With just four physical parameters, we fit the spectrum of the gamma/X-ray pulsars along seven orders of magnitude. We find that all detections can be encompassed in a continuous variation of the model parameters, and pose that their values could likely relate to the closure mechanism operating in the accelerating region. The model explains the appearance of sub-exponential cutoffs at high energies as a natural consequence of synchro-curvature dominated losses, unveiling that curvature-only emission may play a relatively minor role --if any-- in the spectrum of most pulsars. The model also explains the flattening of the X-ray spectra at soft energies as a result of propagating particles being subject to synchrotron losses all along their trajectories. Using this model, we show how observations in gamma-rays can predict the detectability of the pulsar in X-rays, and viceversa."

Read full document.

"Center-Excised X-ray Luminosity as an Efficient Mass Proxy for Future Galaxy Cluster Surveys", by Adam B. Mantz at al

Mantz et allAbstract: "The cosmological constraining power of modern galaxy cluster catalogs can be improved by obtaining low-scatter mass proxy measurements for even a small fraction of sources. In the context of large upcoming surveys that will reveal the cluster population down to the group scale and out to high redshifts, efficient strategies for obtaining such mass proxies will be valuable. In this work, we use high-quality weak lensing and X-ray mass estimates for massive clusters in current X-ray selected catalogs to revisit the scaling relations of the projected, center-excised X-ray luminosity (Lce), which previous work suggests correlates tightly with total mass. Our data confirm that this is the case, with Lce having an intrinsic scatter at fixed mass comparable to that of gas mass, temperature or YX. Compared to these other proxies, however, Lce is less susceptible to systematic uncertainties due to background modeling, and can be measured precisely with shorter exposures. This opens up the possibility of using Lce to estimate masses for large numbers of clusters discovered by new X-ray surveys (e.g. eROSITA) directly from the survey data, as well as for clusters discovered at other wavelengths, with relatively short follow-up observations. We describe a simple procedure for making such estimates from X-ray surface brightness data, and comment on the spatial resolution required to apply this method as a function of cluster mass and redshift. We also explore the potential impact of Chandra and XMM-Newton follow-up observations over the next decade on dark energy constraints from new cluster surveys.

Read full document.

"Projected bounds on ALPs from Athena", by Joseph P. Conlon et al

JPConlon

Abstract: "Galaxy clusters represent excellent laboratories to search for Axion-Like Particles (ALPs). They contain magnetic fields which can induce quasi-sinusoidal oscillations in the X-ray spectra of AGNs situated in or behind them. Due to its excellent energy resolution, the X-ray Integral Field Unit (X-IFU) instrument onboard the Athena X-ray Observatory will be far more sensitive to ALP-induced modulations than current detectors. As a first analysis of the sensitivity of Athena to the ALP-photon coupling gaγγ, we simulate observations of the Seyfert galaxy NGC1275 in the Perseus cluster using the SIXTE simulation software. We estimate that for a 200ks exposure, a non-observation of spectral modulations will constrain gaγγ≲1.5×10−13GeV−1 for ma≲10−12eV, representing an order of magnitude improvement over constraints derived using the current generation of satellites."

Read full document.

Subcategories

Papers related with Athena

Your Athena related publications: Please inform us about your Athena related publications. They will posted in our web site and in the Athena social media.

  • 1
  • 2
  • 3
  • 4
  • 5
  • 6

Overview papers

  • 1

Athena mission proposal and white paper

  • 1

Athena supporting papers

  • 1
  • 2
  • 3