The mystery of the 'Kite' radio source in Abell 2626: insights from new Chandra observations

We present the results of a new Chandra study of the galaxy cluster A2626. The radio emission of the cluster shows a complex system of four symmetric arcs without known correlations with the X-ray emission. The mirror symmetry of the radio arcs toward the center and the presence of two optical cores in the central galaxy suggested that they may be created by pairs of precessing radio jets powered by dual AGNs inside the cD galaxy. However, previous observations failed to observe the second jetted AGN and the spectral trend due to radiative age along the radio arcs, thus challenging this interpretation. The new Chandra observation had several scientific objectives, including the search for the second AGN that would support the jet precession model. We focus here on the detailed study of the local properties of the thermal and non-thermal emission in the proximity of the radio arcs, in order to get more insights into their origin. We performed a standard data reduction of the Chandra dataset deriving the radial profiles of temperature, density, pressure and cooling time of the intra-cluster medium. We further analyzed the 2D distribution of the gas temperature, discovering that the south-western junction of the radio arcs surrounds the cool core of the cluster. We studied the X-ray SB and spectral profiles across the junction, finding a cold front spatially coincident with the radio arcs. This may suggest a connection between the sloshing of the thermal gas and the nature of the radio filaments, raising new scenarios for their origin. A possibility is that the radio arcs trace the projection of a complex surface connecting the sites where electrons are most efficiently reaccelerated by the turbulence that is generated by the gas sloshing. In this case, diffuse emission embedded by the arcs and with extremely steep spectrum should be most visible at very low radio frequencies.Comment: 7 pages, 7 figures. Accepted for publication on A&

Vps28 is involved in the intracellular trafficking of AWD, the Drosophila homolog of NMe1/2

The Awd (abnormal wing discs) gene is the Drosophila homolog of human NME1 and NME2 metastasis suppressor genes. These genes play a key role in tumor progression. Extensive studies revealed that intracellular NME1/2 protein levels could be related to either favorable or poor prognosis depending on tissue context. More recently, extracellular activities of NME1/2 proteins have also been reported, including a tumor- promoting function. We used Drosophila as a genetic model to investigate the mechanism controlling intra- and extracellular levels of NME1/2. We examined the role of several components of the ESCRT (endosomal sorting complex required for transport) complex in controlling Awd trafficking. We show that the Vps28 component of the ESCRT 12I complex is required for maintenance of normal intracellular level of Awd in larval adipocytes. We already showed that blocking of Shibire (Shi)/Dynamin function strongly- lowers Awd intracellular level. To further investigate this down regulative effect, we analyzed the distribution of endosomal markers in wild type and Shi-defective adipocytes. Our results suggest that Awd does not enter CD63-positive endosomes. Interestingly, we found that in fat body cells, Awd partly- colocalizes with the ESCRT accessory component ALiX, the ALG-2 (apoptosis-linked gene 2)-interacting protein X. Moreover, we show that the intracellular levels of both proteins are downregulated by blocking the function of the Dynamin encoded by the shibire gene

Comparative expression profiling of wild type Drosophila Malpighian tubules and von Hippel-Lindau haploinsufficient mutant

The von-Hippel Lindau (VHL) disease is a hereditary genetic disorder that predisposes to the onset of several highly vascularized benign and malignant tumors, developing with elevate frequency in the central nervous system and kidneys. The most-aggressive VHL tumor is ccRCC, the clear-cell renal cell carcinoma, affecting the kidney. VHL disease etiology can be attributed to the inheritance of a VHL loss-of-function allele, typically a deletion (Gnarra et al., 1994; Herman et al., 1994); this facilitates the somatic inactivation of the other allele (through amorphic mutations or gene silencing through promoter methylation), leading to the onset of the tumorous phenotype (Latif et al., 1993). This reveals the haploinsufficient behavior of the VHL gene. The high vascularization of VHL tumors can be explained considering that human VHL protein is the substrate-binding subunit of an E3 ubiquitin ligase (Lonergan et al., 1998; Iwai et al., 1999; Kamura et al., 1999) involved in the poly-ubiquitination of HIF-1α transcription factor. This post-translational modification leads HIF-1α to proteosomal degradation (Maxwell et al., 1999). Loss of VHL function causes the stabilization of HIF-1α, triggering cellular response and adaptation to hypoxic conditions (expression of genes involved in glycolysis, angiogenesis and erythropoiesis) (Bader and Hsu, 2012). While this represents the canonical function of VHL, other HIF-1α-independent function of VHL have been identified, thanks to the contribution of model organisms (Hsu, 2012). Indeed, VHL gene function is conserved and also Drosophila has a VHL homolog, the dVHL gene (Adryan et al., 2000; Aso et al., 2000). dVHL is involved in the development of Drosophila vascular system (Adryan et al., 2000; Hsouna et al., 2010) and in morphogenesis of follicular epithelium of the egg chamber (Duchi et al., 2010). Interestingly, some VHL functions are mediated by Awd, an endocytic mediator whose human orthologs are NME1/2 metastasis suppressors (Rosengard et al., 1989). Awd is broadly required during Drosophila development since it is involved in epithelial morphogenesis (Nallamothu et al., 2008; Woolworth et al., 2009; Ignesti et al., 2014) and required for maintaining genomic stability (Romani et al., 2017). Moreover, Awd is also present into the extracellular fluids of Drosophila larvae (Romani et al., 2016, 2018). In Drosophila, two pairs of monolayered epithelial Malpighian tubules, each composed of 100-150 cells, absolve to osmoregulation and excretion functions (Denholm and Skaer, 2009). Transcriptomic analysis of Malpighian tubules revealed that among genes that are here enriched there are homologs of human genes implicated into renal pathologies (Wang et al., 2004). This justifies the use of Drosophila Malpighian tubules as model system to gain insights into pathophysiology of human kidneys (Dow and Romero, 2010; Miller et al., 2013). The dVHL1.1 allele is a loss of function mutation of the dVHL locus (Duchi et al., 2010; Hsouna et al., 2010). dVHL1.1/+ flies mimic the genetic condition of VHL patients. We carried out a genome-wide gene expression profiling of whole Malpighian tubules dissected from Drosophila females both heterozygous for the dVHL1.1 mutation and with two wild type copies of the dVHL gene. The comparison of differentially expressed genes in the two genetic backgrounds potentially allows to identify genes that are sensible to dVHL functional copy number. Quality control assessments of the data were performed and results obtained from the differential expression analysis were confirmed by qRT-PCR. With this approach we aimed to provide a well-controlled dataset for a better understanding of the VHL disease. Indeed, even if further molecular and functional characterization are needed, human homologs of the differentially expressed genes, if existing, could have a role in the somatic inactivation of the wild type copy of VHL and/or into the very first phase of cancer onset

Radio-continuum spectra of ram pressure stripped galaxies in the Coma Cluster

$Aims:$ We used the nearby Coma Cluster as a laboratory in order to probe the impact of ram pressure on star formation as well as to constrain the characteristic timescales and velocities for the stripping of the non-thermal ISM. $Methods:$ We used high-resolution ($6.5'' \approx 3\,\mathrm{kpc}$), multi-frequency ($144\,\mathrm{MHz} - 1.5\,\mathrm{GHz}$) radio continuum imaging of the Coma Cluster to resolve the low-frequency radio spectrum across the discs and tails of 25 ram pressure stripped galaxies. With resolved spectral index maps across these galaxy discs, we constrained the impact of ram pressure perturbations on galaxy star formation. We measured multi-frequency flux-density profiles along each of the ram pressure stripped tails in our sample. We then fit the resulting radio continuum spectra with a simple synchrotron aging model. $Results:$ We showed that ram pressure stripped tails in Coma have steep ($-2 \lesssim \alpha \lesssim -1$) spectral indices. The discs of galaxies undergoing ram pressure stripping have integrated spectral indices within the expected range for shock acceleration from supernovae ($-0.8 \lesssim \alpha \lesssim -0.5$), though there is a tail towards flatter values. In a resolved sense, there are gradients in spectral index across the discs of ram pressure stripped galaxies in Coma. These gradients are aligned with the direction of the observed radio tails, with the flattest spectral indices being found on the `leading half'. From best-fit break frequencies we estimated the projected plasma velocities along the tail to be on the order of hundreds of kilometers per second, with the precise magnitude depending on the assumed magnetic field strength.Comment: 18 pages, 10 figures, 2 appendices, accepted for publication in A&

Very Large Array observations of the mini-halo and AGN feedback in the Phoenix cluster

(Abridged) The relaxed cool-core Phoenix cluster (SPT-CL J2344-4243) features an extremely strong cooling flow, as well as a mini-halo. Strong star-formation in the brightest cluster galaxy indicates that AGN feedback has been unable to inhibit this cooling flow. We have studied the strong cooling flow in the Phoenix cluster by determining the radio properties of the AGN and its lobes. In addition, we use spatially resolved observations to investigate the origin of the mini-halo. We present new Very Large Array 1-12 GHz observations of the Phoenix cluster which resolve the AGN and its lobes in all four frequency bands, and resolve the mini-halo in L- and S-band. Using our L-band observations, we measure the total flux density of the radio lobes at 1.5 GHz to be $7.6\pm0.8$ mJy, and the flux density of the mini-halo to be $8.5\pm0.9$ mJy. Using L- and X-band images, we produce the first spectral index maps of the lobes from the AGN and measure the spectral indices of the northern and southern lobes to be $-1.35\pm0.07$ and $-1.30\pm0.12$, respectively. Similarly, using L- and S-band data, we map the spectral index of the mini-halo, and obtain an integrated spectral index of $\alpha=-0.95 \pm 0.10$. We find that the mini-halo is most likely formed by turbulent re-acceleration powered by sloshing in the cool core due to a recent merger. In addition, we find that the feedback in the Phoenix cluster is consistent with the picture that stronger cooling flows are to be expected for massive clusters like the Phoenix cluster, as these may feature an underweight supermassive black hole due to their merging history. Strong time variability of the AGN on Myr-timescales may help explain the disconnection between the radio and the X-ray properties of the system. Finally, a small amount of jet precession likely contributes to the relatively low ICM re-heating efficiency of the mechanical feedback.Comment: 12 pages, 14 figures. Accepted for publication in A&

Valutazione del rischio elettromagnetico ai sensi del D.Lgs. 81/2008 presso l\u27Azienda Ospedaliera Mellino Mellini Chiari (Brescia)

.La relazione riferisce i risultati della campagna di misura effettuata nei giorni dal 6 al 9 giugno 2011 e successivamente il 4 e il 6 luglio 2011. La campagna ? stata preceduta da un sopralluogo (21 marzo 2011) alle strutture di competenza dell\u27Azienda Mellino Mellini (Chiari, Iseo, Rovato, Palazzolo ed Orzinuovi) per la definizione delle azioni da intraprendere per la valutazione del rischio elettromagnetico in conformit? al D.Lgs. 81/2008. Pi? specificatamente gli obiettivi della campagna di misura sono stati i seguenti. Misura dei campi elettromagnetici (EM) in punti predefiniti per la determinazione dei livelli di campo EM presenti. Determinazione dei campi elettrici, magnetici ed elettromagnetici emessi da apparecchiature elettromedicali quali magnetoterapia e radarterapia . Misura dei campi magnetici (in particolare induzione magnetica) presenti nei locali tecnici quali cabina elettrica e impianti di condizionamento. Valutazione dell\u27intensit? dell\u27induzione magnetica all\u27interno e in prossimit? di incubatrici e culle termiche (Chiari e Iseo). Valutazione delle specifiche tecniche di elettrobisturi (Blocco Operatorio di Iseo). Caratterizzazione della presenza di eventuali interferenze EM dovute alla rete wireless (reparto di terapia intensiva di cardiologia di Chiari) o da disturbi EM presenti su apparecchiature per diagnostica (neurologia di Chiari)

Unveiling the Interplay between the GASP Jellyfish Galaxy JO194 and Its Environment with Chandra

X-ray studies of jellyfish galaxies opened a window into the physics of the interplay between the intracluster medium (ICM) and interstellar medium (ISM). In this paper, we present the study of an archival Chandra observation of the GASP jellyfish galaxy JO194. We observe X-ray emission extending from the stellar disk to the unwinding spiral arms with an average temperature of kT = 0.79 ± 0.03 keV. To investigate the origin of the X-ray emission, we compare the observed X-ray luminosities with those expected from the star formation rates (SFRs) obtained from Hα emission. We estimate an X-ray luminosity excess of a factor ∼2–4 with respect to the SF; therefore, we conclude that SF is not the main event responsible for the extended X-ray emission of JO194. The metallicity in the spiral arms (Z = 0.24+0.19 Z ) is consistent with that of the ICM around JO194 -0.12 (Z = 0.35 ± 0.07); thus, we suggest that ICM radiative cooling dominates the X-ray emission of the arms. We speculate that the X-ray plasma results from the ISM–ICM interplay, although the nature of this interplay is still mostly unknown. Finally, we observe that the X-ray properties of JO194 are consistent with those of two other GASP galaxies with different stellar mass, phase-space conditions in their hosting clusters, and local ICM conditions. We suggest that the conditions required to induce extended X-ray emission in jellyfish galaxies are established at the beginning of the stripping, and they can persist on long timescales so that galaxies in different clusters and evolutionary stages can present a similar extended X-ray emission