iiinova — where your digital self keeps evolving

Andrea Botteon @andreabotteon.bsky.social · 07/10/2026

The paper on the Treble Clef radio phoenix has been accepted ~1 week ago in @AandA_journal! Today you can find the replacement on arXiv arxiv.org/abs/2607.06659

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Andrea Botteon @andreabotteon.bsky.social · 02/09/2026

New MeerKAT results on A520, by Giacintucci+ This "train wreck cluster" is undergoing a complex merger. The 1.3 GHz data presented unveil a plethora of merger-generated non-phenomena, with new radio structures discovered on very large scales arxiv.org/abs/2609.00156

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Andrea Botteon @andreabotteon.bsky.social · 01/09/2026

Investigating a 13 Mpc intra-cluster filament with POSSUM, by Stuardi+ The RM of background sources is used to constrain the B field strength, with main uncertainties due to the Galactic foreground modeling (a critical factor for extragalactic studies) arxiv.org/abs/2608.28758

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Joe Callingham @astrojoe.bsky.social · 31/08/2026

The future of low frequency radio astronomy is space! It is only in space that we can unlock the last part of the electromagnetic spectrum that has yet to be explored. I am fortunate to play a minor part in this team lead by Joe Lazio for the MegaWave Radio Surveyor space mission.

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Andrea Botteon @andreabotteon.bsky.social · 31/08/2026

Delayed announcement of two papers appeared on arXiv last week: -In @cjriseley.bsky.social+ we performed a radio/X-ray study of the cool core cluster 2A 0335+096 arxiv.org/abs/2608.24309 -In Rajpurohit+ we investigated the radio emission from the famous Stephan's Quintet arxiv.org/abs/2608.26461

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Hossam Khalil @hossam.bsky.social · 19/08/2026

Paper day! My second 1st-author paper has been accepted for publication in A&A and is now on the arXiv: arxiv.org/abs/2608.17735. We use X-ray data from the first eROSITA-DE all-sky survey (eRASS1) to study the hot gas (baryon) budget of nearby galaxy groups out to the virial radius🧵☄️

arxiv.org

eROSITA cosmology with galaxy groups: hot gas budget out to the virial radius

Non-gravitational processes that expel hot gas beyond the virial regions of groups and clusters of galaxies, known collectively as baryonic feedback, play a key role in reshaping the matter distributi...

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Andrea Botteon @andreabotteon.bsky.social · 17/07/2026

This is the first time that this novel technique was used to investigate the topology of B in a cluster from its center to its dynamically active outskirts. Our work shows how low-freq observations can be used to probe the structure of cluster magnetic fields on Mpc scales 11/11

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Andrea Botteon @andreabotteon.bsky.social · 17/07/2026

Important: we could not have obtained these results with polarization. SIG is independent on that, as it operates on images in total intensity (where diffuse cluster emission is brighter). A2255 was an obvious case where to use this method thanks to the deep data available 10/11

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Andrea Botteon @andreabotteon.bsky.social · 17/07/2026

The central region of A2255 is extremely messy in radio, as it shows surface brightness decrements, enhancements, edges, and filamentary structures associated with turbulent and shocked regions. That is probably why the structure of B here is more messy 9/11

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Andrea Botteon @andreabotteon.bsky.social · 17/07/2026

Where we have information from polarization, we also showed that the field orientation inferred from SIG is in well in agreement with that derived from polarization, although this comparison could be performed only in a small region of the cluster 8/11

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Andrea Botteon @andreabotteon.bsky.social · 17/07/2026

This is in line with what we found in our MHD simulations, where we can identify similar structures of large-scale radial/tangential fields due to stretching and compression of the field during the merger 7/11

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Andrea Botteon @andreabotteon.bsky.social · 17/07/2026

We found that the large-scale field exhibits preferential orientations in distinct regions of the cluster (e.g. in the relics and halo extensions), suggesting that the dynamics of the cluster formation process is shaping it 6/11

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Andrea Botteon @andreabotteon.bsky.social · 17/07/2026

By using the synchrotron intensity gradient (SIG) technique, we mapped the topology of the large-scale ICM magnetic field that is traced by the large-scale radio emission permeating the cluster 5/11

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Andrea Botteon @andreabotteon.bsky.social · 17/07/2026

A2255 is known to host complex radio emission on various scales: halos, relics, bridges, filaments, complex AGN etc. All these structures are detected at higher S/N in the new images 4/11

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Andrea Botteon @andreabotteon.bsky.social · 17/07/2026

The final images provide a glimpse of what should be routinely observed in clusters with SKA-Low in the near future: the sensitivity at 7.1"x4.3" is 24 muJy/beam! The highest ever achieved on a galaxy cluster 3/11

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Andrea Botteon @andreabotteon.bsky.social · 17/07/2026

The @astronnl.bsky.social LOFAR Ultra-Deep Field consists of 336 h of observations at 144 MHz on the low-z, merging and massive, cluster Abell 2255. After a long processing (the volume of raw data is ~200 TB), our analysis was based on the 224 h of data with best quality 2/11

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Andrea Botteon @andreabotteon.bsky.social · 17/07/2026

We used the deepest radio observations ever carried out on a galaxy cluster to map the topology of the large-scale magnetic field underlying one of the largest radio emission (~5 Mpc) detected in the ICM 🧲. The paper is in press in @aanda-journal.bsky.social 1/11 arxiv.org/abs/2607.14209

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Andrea Botteon @andreabotteon.bsky.social · 09/07/2026

We spent almost 3 years to follow-up this source with different facilities. It was fun to see how the project developed and how the team worked together to make the analysis a success! The paper is submitted to @aanda-journal.bsky.social 10/10

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Andrea Botteon @andreabotteon.bsky.social · 09/07/2026

The Treble Clef is an example of highly filamentary with ultra-steep spectrum. @LOFAR was crucial to determine its structure, and with the upcoming @LOFAR 2.0 update we will perform these studies even better thanks to the improved sensitivity at ultra-low frequency 9/10

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Andrea Botteon @andreabotteon.bsky.social · 09/07/2026

We proposed a simplified scenario which may explain the origin of the Treble Clef and its peculiar morphology and structures. This scenario is related to the ongoing merger and the turbulence injected in the ICM 8/10

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Andrea Botteon @andreabotteon.bsky.social · 09/07/2026

We performed a resolved study of the main filament of the source, discussing its spectral variations. This emission seems consistent with being originated form a common electron population whose evolution has been modulated by different local conditions and timescales 7/10

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Andrea Botteon @andreabotteon.bsky.social · 09/07/2026

...which is firmly confirmed by the detection of diffuse thermal X-ray emission thanks to @eROSITA_SRG and @chandraxray observations: the Treble Clef belongs to a massive, merging galaxy cluster located in the Zone of Avoidance 6/10

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Andrea Botteon @andreabotteon.bsky.social · 09/07/2026

This source lays at very low Galactic latitude, where the identification of clusters is made complex due to Galactic absorption. Still, hints of a galaxy overdensity and red sequence in the NIR image and color-magnitude diagram possibly suggest the presence of a cluster... 5/10

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Andrea Botteon @andreabotteon.bsky.social · 09/07/2026

The source has extremely steep and curved spectra: this characteristic and its filamentary morphology indicates that we are looking at a radio phoenix in a galaxy cluster...but where is the cluster? 4/10

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Andrea Botteon @andreabotteon.bsky.social · 09/07/2026

In addition to the @LOFAR data at 150 MHz, we used @LOFAR observations at 50 MHz and followed-up the source also with the @NCRA_Outreach uGMRT at 400 and at 650 MHz. This is how it looks at different frequencies 3/10

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Andrea Botteon @andreabotteon.bsky.social · 09/07/2026

This source was already studied at 150 MHz, in its latest dedicated study, published more than 20 years ago (Green+04). The resolution at that time was quite poor, and it was proposed that it could be a source associated with a galaxy cluster 2/10

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Andrea Botteon @andreabotteon.bsky.social · 09/07/2026

Paper alert! Let me introduce you the "Treble Clef" radio phoenix. This is a bright and highly filamentary radio source we noticed with @LOFAR (in LoTSS) a few years ago and followed-up over the past years... 1/10 arxiv.org/abs/2607.06659

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Roland Timmerman @rtimmerman.bsky.social · 01/07/2026

Today is paper day again! Right now on arXiv: LOFAR-VLBI observations of Abell 2199, revealing a set of steep-spectrum synchrotron threads for the first time. Also, the radio lobes show an almost perfectly homogeneous CRe population. (arxiv.org/abs/2606.30714 w/ @andreabotteon.bsky.social)

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Andrea Botteon @andreabotteon.bsky.social · 01/07/2026

New @LOFAR-VLBI observations of 3C338 in A2199, by @rtimmerman.bsky.social+ (w/ myself++) We studied the known emission bridge + discovered narrow synchrotron threads with alpha>3 likely tracing magnetic threads in the ICM. Curiously, the lobes show uniform spectral indexes arxiv.org/abs/2606.30714

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Andrea Botteon @andreabotteon.bsky.social · 10/06/2026

The dynamics of the Anglerfish cluster, by Destafanis+ (w/ @IacopoBart, @fabiogasta, @sghizza69, @mcrossetti_twit++) The combination of radio, X-ray, optical observations + comparison with numerical simulations give insights on the ongoing complex merger arxiv.org/abs/2606.10483

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Andrea Botteon @andreabotteon.bsky.social · 09/06/2026

New @XRISM_jp results on A1795, by Sarkar+ Low turbulence and bulk velocities are measured in the ICM, with indication of radial declining sigma_v and P_NT/P_T. Evidence for for multiphase gas and resonant scattering are also reported arxiv.org/abs/2606.08097

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Andrea Botteon @andreabotteon.bsky.social · 26/05/2026

We have opened a PhD position at INAF-IRA on the project "Unveiling the origin of diffuse radio emission in galaxy clusters through MeerKAT and LOFAR observations" see info.ira.inaf.it/wp-content/u... Deadline: June 15th For more details on the application, see www.unibo.it/en/study/phd...

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Andrea Botteon @andreabotteon.bsky.social · 08/05/2026

Big @LOFAR paper on clusters today, by @CStuardi+ We searched for diffuse emission in all clusters in LoTSS-DR3 (3000+ clusters over 19k+ deg^2) and report all the detections. This big effort required relying on Radio U-Net, a CNN optimized for this task arxiv.org/abs/2605.06400

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Durham University @durham.ac.uk · 28/04/2026

@icc-durham.bsky.social @durhamphysics.bsky.social researchers are part of the FLAMINGO project, which has released one of the largest datasets in cosmology! This gives scientists worldwide a new way to explore how the Universe evolves 👉 tinyurl.com/339vteyc @dirac-hpc.bsky.social, @ukri.org

A visualisation of the most massive cluster in the simulation of a cube. Blue, purple, yellow and white colours swirl against a dark blue backdrop.

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Andrea Botteon @andreabotteon.bsky.social · 26/03/2026

.@LOFAR observations at 30-58 MHz of the Perseus Cluster, by @ChristianGroe18+ (w/ myself++) Interestingly, the spectrum of the Mpc-scale radio halo recently reported is not steeper than that of the mini halo, though this measurement remains challenging! arxiv.org/abs/2603.23587

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Andrea Botteon @andreabotteon.bsky.social · 04/03/2026

What is the origin of 1LHAASO J0343+5254u? by @hen_edler, @itsMariaArias, myself, @cbassa.bsky.social Our multi-band analysis suggests that the PWN candidate previously proposed to be its origin is actually an obscured galaxy cluster, unrelated to the LHAASO emission arxiv.org/abs/2603.03164

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Alessandro Ignesti @a-ignesti.bsky.social · 26/02/2026

#paperday #Extragalactic What determines whether a galaxy can become a jellyfish galaxy? Thanks to new Meerkat data, we now propose that this may be due to a combination of supersonic orbits and interactions with the magnetic field of the galaxy cluster. More at arxiv.org/abs/2602.21821

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RAS Journals @rasjournals.bsky.social · 26/02/2026

Published in #MNRAS: "Wiggling through the ICM: multiresolution radio imaging of a tailed radio galaxy in MACS J1354.6+7715", Gani et al. These are Figs. 1 & 6: please visit academic.oup.com/mnras/articl... to read the paper. @royalastrosoc.bsky.social @academic.oup.com

High-resolution LOFAR HBA image of the tailed radio galaxy (C) in the galaxy cluster MACS J1354.6+7715, observed at 144 MHz. A and B denotes two compact radio sources, while D marks an additional radio source detected in the field. Please see the paper for the full caption.

Composite image of the cluster combining optical, radio, and X-ray data. Please see the paper for the full caption.

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Andrea Botteon @andreabotteon.bsky.social · 19/02/2026

LoTSS-DR3, by Shimwell+ (w/ many) We have released the largest collection of data from a radio survey: 13M+ sources detected over 19k deg^2 (88% of the Northern sky). This took ~13k h of @LOFAR observations, ~18 PT of data, and 10+ years of work. Data are public from today arxiv.org/abs/2602.15949

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Daniel Pomarède @pomarede.bsky.social · 17/02/2026

Great paper on the Great Attractor, just published by The Open Journal of Astrophysics doi.org/10.33232/001... @ojastro.bsky.social 🧪 #Cosmology #Cosmicflows

Screenshot from the frontpage of the Open Journal of Astrophysics, featuring the following article informations. Title reads "Revisiting the Great Attractor: The Local Group's streamline trajectory, cosmic velocity and dynamical fate". Authors list: Richard Stiskalek, Harry Desmond, Stuart McAlpine, Guilhem Lavaux, Jens Jasche, Michael J. Hudson. Summary reads "The study revisits the Great Attractor concept, finding that it doesn't dominate the Local Group's cosmic velocity; multiple structures contribute to the motion, with no single attractor accounting for it". Dated February 17, 2026. Background image featuring an allsky map of the depth of the inferred Classical Great Attractor basin as a function of sky position in Galactic coordinates.

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Andrea Botteon @andreabotteon.bsky.social · 06/02/2026

A radio relic mimicking a radio halo? by @paola-dominguez.bsky.social+ (w/ @jzuhone.bsky.social @emstar.bsky.social myself+) This could be the case of MACSJ0018.5+1626, where numerical simulations show that the radio emission could be due to a relic seen face-on arxiv.org/abs/2602.05050

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Andrea Botteon @andreabotteon.bsky.social · 26/01/2026

Radio observations A1775 and A1795, by vanWeeren+ (w/ @cjriseley.bsky.social, @rtimmerman.bsky.social, myself+) MeerKAT @SKA_Africa recovers the known diffuse emission in both systems. Interestingly, the large-scale halo in A1795 is compatible with a hardonic origin... arxiv.org/abs/2601.16288

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Andrea Botteon @andreabotteon.bsky.social · 21/01/2026

New study of two merging galaxy clusters, by Srikanth+ (w/ myself, @roxycas++) @LOFAR, GMRT, and @ESA_XMM observations are combined to investigate the nature of the diffuse emission in A773 and A1351. Congrats to Koushika on her first paper! arxiv.org/abs/2601.13316

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Andrea Botteon @andreabotteon.bsky.social · 23/12/2025

What comes after paper I? Paper II! Still led by @e_derubeis In the new paper, a more detailed investigation about the origin of the filaments is done by combining LOFAR @astronnl.bsky.social data with new uGMRT and VLA observations at higher frequency arxiv.org/abs/2512.19471

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Andrea Botteon @andreabotteon.bsky.social · 10/12/2025

Paper accepted for publication in @aanda-journal.bsky.social! You can find the accepted version in today's replacements on arXiv (arxiv.org/abs/2509.14348). The only notable update is that we left the merger scenario open, as we are not sure if the clusters are observed pre or post collision

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Andrea Botteon @andreabotteon.bsky.social · 01/12/2025

A fresh look at Abell 2163, by Santra+ (including myself) This is one of the hottest, most massive, and brightest cluster in the sky. New uGMRT band 3 and band 4 data are used to study the giant (among the largest!) radio halo hosted in this merging system arxiv.org/abs/2511.22124

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