Walk on the Low Side: LOFAR explores the low-frequency radio emission of GASP jellyfish galaxies

Jellyfish galaxies, characterized by long filaments of stripped interstellar medium extending from their disks, are the prime laboratories to study the outcomes of ram pressure stripping. At radio wavelengths, they often show unilateral emission extending beyond the stellar disk, and an excess of radio luminosity with respect to that expected from their current star formation rate. We present new 144 MHz images provided by the LOFAR Two-metre Sky Survey for a sample of six galaxies from the GASP survey. These galaxies are characterized by a high global luminosity at 144 MHz ($6-27\times10^{22}$ W Hz$^{-1}$), in excess compared to their ongoing star formation rate. The comparison of radio and H$\alpha$ images smoothed with a Gaussian beam corresponding to $\sim$10 kpc reveals a sub-linear spatial correlation between the two emissions with an average slope $k=0.50$. In their stellar disk we measure $k=0.77$, which is close to the radio-to-star formation linear relation. We speculate that, as a consequence of the ram pressure, in these jellyfish galaxies the cosmic rays transport is more efficient than in normal galaxies. Radio tails typically have higher radio-to-H$\alpha$ ratios than the disks, thus we suggest that the radio emission is boosted by the electrons stripped from the disks. In all galaxies, the star formation rate has decreased by a factor $\leq10$ within the last $\sim10^8$ yr. The observed radio emission is consistent with the past star formation, so we propose that this recent decline may be the cause of their radio luminosity-to-star formation rate excess.Comment: 22 pages, 7 figures. Accepted for publication on ApJ on 24/08/202

The role of environment on quenching, star formation and AGN activity

Galaxies undergoing ram pressure stripping in clusters are an excellent opportunity to study the effects of environment on both the AGN and the star formation activity. We report here on the most recent results from the GASP survey. We discuss the AGN-ram pressure stripping connection and some evidence for AGN feedback in stripped galaxies. We then focus on the star formation activity, both in the disks and the tails of these galaxies, and conclude drawing a picture of the relation between multi-phase gas and star formation.Comment: Proceedings of the IAU Symposium 359 "Galaxy evolution and feedback across different environments", editors T. Storchi-Bergmann, R. Overzier, W. Forman & R. Riffel - final versio

Continuous printing system

This thesis paper aims to convert a commercial printer to a continuous printer. Commercial printers can be configured in such a way that it can print longer than its usual printing size. However, this does not eliminate the page break feature and printing on continuous paper is not possible. This research aims to implement a continuous printer that can print images that are of longer length than the usual A4 size paper which is 11 inches in length. A commercial printer is the main machine for our prototype. The program is capable of displaying the image in its display window. Rio6z, when prompted to print, will start the printing process. A commercial printer is equipped with a microcontroller that regulates and monitors signals. The software, Rio6Z, breaks images that are larger than the maximum limit of the printer into pages. It also displays a preview of the image to be printed. Through the use of the software and the converted commercial printer, printing on continuous papers can be done

Evidence for Mixing between ICM and Stripped ISM by the Analysis of the Gas Metallicity in the Tails of Jellyfish Galaxies

none14noneAndrea Franchetto; Stephanie Tonnesen; Bianca M. Poggianti; Benedetta Vulcani; Marco Gullieuszik; Alessia Moretti; Rory Smith; Alessandro Ignesti; Cecilia Bacchini; Sean McGee; Neven Tomičić; Matilde Mingozzi; Anna Wolter; Ancla MüllerFranchetto, Andrea; Tonnesen, Stephanie; Poggianti, Bianca M.; Vulcani, Benedetta; Gullieuszik, Marco; Moretti, Alessia; Smith, Rory; Ignesti, Alessandro; Bacchini, Cecilia; Mcgee, Sean; Tomičić, Neven; Mingozzi, Matilde; Wolter, Anna; Müller, Ancl

GASP XXXIX: MeerKAT hunts Jellyfish in A2626

We present MeerKAT H I observations of six jellyfish candidate galaxies (JFCGs) in the galaxy cluster, A2626. Two of the six galaxies JW100 and JW103, which were identified as JFCGs from B-band images, are confirmed as jellyfish galaxies (JFGs). Both of the JFGs have low H I content, reside in the cluster core, and move at very high velocities (~ 3σcl). The other JFCGs, identified as non-jellyfish galaxies, are H I rich, with H I morphologies revealing warps, asymmetries, and possible tidal interactions. Both the A2626 JFGs and three other confirmed JFGs from the GASP sample show that these galaxies are H I stripped but not yet quenched. We detect H I, H α, and CO(2-1) tails of similar extent (~50 kpc) in JW100. Comparing the multiphase velocity channels, we do not detect any H I or CO(2-1) emission in the northern section of the tail where H α emission is present, possibly due to prolonged interaction between the stripped gas and the intracluster medium. We also observe an anticorrelation between H I and CO(2-1), which hints at an efficient conversion of H I to H2 in the southern part of the tail. We find that both ram-pressure stripping and H I-to-H2 conversion are significant depletion channels for atomic gas. H I-to-H2 conversion is more efficient in the disc than in the tail