Andrea Botteon

Check for the wonderful science that @axisprobe.bsky.social would enable in the white book uploaded today in arXiv: arxiv.org/abs/2511.00253
I've participated with a chapter on "X-ray and radio surface brightness edges in the ICM", you can find it in the Galaxies GO Science section (page 69)

News on Abell 754 from @XRISM_jp, by Okabe+ and Omiya+
Combining the gas kinematic from XRISM and WL from Subauru, a new merger scenario is proposed. The "3rd dimension" has been unlocked thanks to XRISM 😀
arxiv.org/abs/2510.16291
arxiv.org/abs/2510.16553

Color rendering of the dark matter particle distribution from a N-body simulation of a LCDM model. Dark matter halos are visible as clumps of different sizes. The color coding follows the mass of the halos, with large halos appearing redder and small halos appearing bluer. The characteristic filamentary structure of the Cosmic Web is striking. Simulation credit: RAMSES. Image credit: S. Colombi.

in the #arXiv

Numerical Cosmology

by Romain Teyssier
arxiv.org/abs/2510.13129 🧪 #Cosmology

I also had two papers come out this month! I worked on the first XRISM results from the Perseus cluster and got time on XRISM to observe A1914, which we discovered was undergoing a line-of-sight merger! 🔭

To conclude, this work adds to the growing effort to investigate nonthermal phenomena outside the denser and well-studied regions of the ICM. Future instruments like @SKAO will likely probe these regions more efficiently. Paper submitted 7/7

What about the uGMRT non-detection? Since diffuse sources in cluster pairs are rare, even spectral limits would help to understand the mechanisms generating the emission. However, the MeerKAT emission is unfortunately too faint to provide a meaningful limit with the uGMRT... 6/7

We compared this extended emission with radio bridges and halos. While its classification is uncertain, its properties align with that expected for a diffuse emission generated in an early stage of the merger 5/7

The radio emission nicely follows the elongation of the X-ray emission from the clusters and intra-cluster bridge, suggesting that it is likely generated as consequence of the cluster-cluster encounter. In-between the clusters, the radio emission is enhanced 4/7

After careful analysis and removal of discrete sources, we confirmed the presence of the extended emission. The large-FoV images show that diffuse emission is present only at the position of the cluster pair in the MeerKAT field, while we have a non-detection with the uGMRT 3/7

The clusters are interacting and are likely observed shortly after pericenter passage. From the MeerKAT images, we noticed "excess" diffuse emission in the intra-cluster region 2/7

New paper alert! We studied a galaxy cluster pair with @SKA_Africa MeerKAT UHF and @NCRA_Outreach uGMRT band 3 data and found diffuse emission between the two clusters! 1/7
arxiv.org/abs/2509.14348

Aaand the paper has been accepted! The accepted version of the paper was posted on arXiv on Aug 19: arxiv.org/abs/2505.05415

Where is the counter lobe? An interesting hypothesis is that it could have been stretched as a consequence of the sloshing in the system, resulting in what is now observed as bridge/arc. See also our recent MeerKAT paper on Ophiuchus (arxiv.org/abs/2504.16158)!

Low frequency observations of the Ophiuchus cluster, by Giacintucci+
The giant fossil lobe is studied in detail. The new data show steep spectrum filamentary structures embedded in the lobe. The lobe extends up to 820 kpc from the cluster center
arxiv.org/abs/2508.20190

.@XRISM_jp obs of the Ophiuchus cluster, by Fujita+
A low velocity dispersion is measured in the inner and outer regions (115 km/s at <25kpc, 186 km/s at 25-50 kpc). The same goes for the bulk velocity (8 km/s vs 104 km/s): is the sloshing at its minimum?
arxiv.org/abs/2507.00126

(w/ @cjriseley.bsky.social, @annalisa-astro.bsky.social, @CStuardi, @FraLoi1)

The magnetic field in A2142, by Pagliotta+
A rotation measure and polarization study is performed with MeerKAT. The magnetic field profile of the ICM is drawn, indicating a central field strength of 9.5 muG at the cluster center.
arxiv.org/abs/2507.00114

MeerKAT observations of CHEX-MATE clusters, by Balboni+ (w/ @annalisa-astro.bsky.social, myself++)
A sample of 21 massive clusters is studied. Diffuse radio emission is detected in all systems (new halos and relics!)
arxiv.org/abs/2507.00133

Happy to have been a coauthor on this paper led by Maria Arias and @rtimmerman.bsky.social looking at the crab nebula with the full International #LOFAR Telescope that was put on arxiv yesterday! Lots of nice sub-arcsecond detail is revealed. Go check out the paper on arxiv arxiv.org/abs/2506.19460

📢Paper and press releases day! We report the first-ever unambiguous detection of WHIM/missing baryons in a single cosmic filament using @ESA_XMM
and @JAXA_en
Suzaku data! It's the first time observations agree with LCDM simulations for the nature of WHIM www.aanda.org/articles/aa/...

Premi Sait 2025, ecco i vincitori Polveri interstellari e ammassi di galassie sono al centro delle ricerche premiate quest’anno dalla Società astronomica italiana. Durante la cerimonia tenutasi oggi a Firenze, sono stati assegnati il ...

Vanno ad Andrea Botteon e a Massimiliano Parente i due premi da duemila euro ciascuno della Società astronomica italiana consegnati oggi a Firenze. Congratulazioni!

The central region of A3667 in hard X-rays, by @MSMirakhor+@astroswalker
A @NASANuSTAR observation of the cluster is presented. The spectrum is better described by a 2T thermal model. An updated limit of B > 0.2 muG is provided from the lack of IC emission
arxiv.org/abs/2505.20453

Thin filaments in the tails of A2255, by DeRubeis+ (w/ myself, @jurjen93.bsky.social+)
A2255 is known to be a "mess" (arxiv.org/abs/2006.04808). The new @LOFAR-VLBI images add further complexity in the system, this time revealing small-scale structures in its radio galaxies
arxiv.org/abs/2505.13595

The Evolutionary Map of the Universe: A new radio atlas for the southern hemisphere sky We present the Evolutionary Map of the Universe (EMU) survey conducted with the Australian Square Kilometre Array Pathfinder (ASKAP). EMU aims to deliver the touchstone radio atlas of the southern hem...

A day late posting but after a lot of hard work I give you the survey overview papers for the EMU & POSSUM ASKAP surveys #EMU survey arxiv.org/abs/2505.08271 and the #POSSUM survey arxiv.org/abs/2505.08272 🔭

The cascade of kinetic and magnetic energy from large to small scales in galactic-style turbulence behaves significantly different to the theoretical models that we regularly assume work.

www.nature.com/articles/s41...

Published in @natastron.nature.com

Our work is based on @LOFAR, MeerKAT @SKA_Africa, and uGMRT @NCRA_Outreach observations. Submitted to AAS journals

To summarize, the studied halos with LLS > 2 Mpc have properties in common with that of classical radio halos. Sensitive observations at high-frequency are also able to detect the peripheral emission and are crucial to remove the contamination of discrete sources
4/4

We pointed out how a second "outer component" of the halo surface brightness profile can arise when an improper source subtraction/masking is performed. Also the sector choice is critical, as different geometries, directions, and centers can generate the second component
3/4

These halos follow a single exponential profile in surface brightness, despite their large extents and complex dynamical state, and have emissivities similar to those of the other halos known. These massive clusters were good candidates to hosts the so-called mega halos
2/4

Radial properties of radio halos, by Rajpurohit+ (w/ myself+)
New radio halos with LLS>2 Mpc are reported, even at high-frequency. We measured the surface brightness and spectral properties of the emission, obtaining important results (more below)
arxiv.org/abs/2505.05415
1/4