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arXiv · 2601.18762

Virgo Filaments VI: H$\alpha$ clumps in the filaments around the Virgo galaxy cluster

G. Nagaraj·P. Jablonka·R. A. Finn·Y. M. Bahé·F. Combes·G. Castignani·B. Vulcani·G. Rudnick·D. Zakharova·R. A. Koopmann·D. Zaritsky·K. Conger
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Abstract

It is still not clear which environmental processes operate in filaments. Given the ubiquity of filaments and their importance in feeding clusters, a proper understanding of these mechanisms is crucial to a more complete picture of galaxy evolution. To investigate them, we need large galaxy samples with spatially resolved information. As part of this effort, we analyse resolved H$\alpha$ maps of 685 galaxies inside and outside the filaments around the Virgo cluster in addition to extensive measurements of integrated physical properties. We create a pipeline to decompose the H$\alpha$ images into individual clumps that trace star forming regions. We find that the number and average size of clumps in a galaxy are well-defined functions of distance and angular resolution. In particular, the power-law relation between the number of clumps and the distance of a galaxy is consistent with a fractal structure of star forming regions. We formulate an algorithm to compare filament and non-filament galaxies after removing observational differences. Although we do not have any conclusive evidence for a difference in clump size distributions between filament and non-filament galaxies, we do find that filament galaxies have slightly more peripheral clumps than their non-filament counterparts.

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G. Nagaraj, P. Jablonka, R. A. Finn, Y. M. Bahé, F. Combes, G. Castignani, B. Vulcani, G. Rudnick, D. Zakharova, R. A. Koopmann, D. Zaritsky, K. Conger. 2026-01-26. Virgo Filaments VI: H$\alpha$ clumps in the filaments around the Virgo galaxy cluster. https://doi.org/10.1051/0004-6361%2F202659147

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