Gas-phase metallicity of local AGN in the GASP and MaNGA surveys: the role of ram-pressure stripping

Growing evidence in support of a connection between Active Galactic Nuclei (AGN) activity and the Ram-Pressure Stripping (RPS) phenomenon has been found both observationally and theoretically in the past decades. In this work, we further explore the impact of RPS on the AGN activity by estimating the gas-phase metallicity of nuclear regions and the mass-metallicity relation of galaxies at $z \leq$ 0.07 and with stellar masses $\log {\rm M}_* / {\rm M}_\odot \geq 9.0$, either experiencing RPS or not. To measure oxygen abundances, we exploit Integral Field Spectroscopy data from the GASP and MaNGA surveys, photoionization models generated with the code CLOUDY and the code Nebulabayes to compare models and observations. In particular, we build CLOUDY models to reproduce line ratios induced by photoionization from stars, AGN, or a contribution of both. We find that the distributions of metallicity and [O III]$\lambda$5007 luminosity of galaxies undergoing RPS are similar to the ones of undisturbed galaxies. Independently of the RPS, we do not find a correlation between stellar mass and AGN metallicity in the mass range $\log {\rm M}_* / {\rm M}_\odot \geq 10.4$, while for the star-forming galaxies we observe the well-known mass-metallicity relation (MZR) between $9.0 \leq \log \ {\rm M}_* /{\rm M}_\odot \leq 10.8$ with a scatter mainly driven by the star-formation rate (SFR) and a plateau around $\log {\rm M}_* / {\rm M}_\odot \sim 10.5$. The gas-phase metallicity in the nuclei of AGN hosts is enhanced with respect to those of SF galaxies by a factor of $\sim$ 0.05 dex regardless of the RPS

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

Deep phenotyping of the neuroimaging and skeletal features in KBG syndrome: a study of 53 patients and review of the literature

Background: KBG syndrome is caused by haploinsufficiency of ANKRD11and is characterised by macrodontia of upper central incisors, distinctive facial features, short stature, skeletal anomalies, developmental delay, brain malformations and seizures. The central nervous system (CNS) and skeletal features remain poorly defined. Methods: CNS and/or skeletal imaging were collected from molecularly confirmed individuals with KBG syndrome through an international network. We evaluated the original imaging and compared our results with data in the literature. Results: We identified 53 individuals, 44 with CNS and 40 with skeletal imaging. Common CNS findings included incomplete hippocampal inversion and posterior fossa malformations; these were significantly more common than previously reported (63.4% and 65.9% vs 1.1% and 24.7%, respectively). Additional features included patulous internal auditory canal, never described before in KBG syndrome, and the recurrence of ventriculomegaly, encephalic cysts, empty sella and low-lying conus medullaris. We found no correlation between these structural anomalies and epilepsy or intellectual disability. Prevalent skeletal findings comprised abnormalities of the spine including scoliosis, coccygeal anomalies and cervical ribs. Hand X-rays revealed frequent abnormalities of carpal bone morphology and maturation, including a greater delay in ossification compared with metacarpal/phalanx bones. Conclusion: This cohort enabled us to describe the prevalence of very heterogeneous neuroradiological and skeletal anomalies in KBG syndrome. Knowledge of the spectrum of such anomalies will aid diagnostic accuracy, improve patient care and provide a reference for future research on the effects ofANKRD11variants in skeletal and brain development

Long-term variability of the gamma-ray emitting NLSy1 PKS2004-447

Le Narrow-Line Seyfert 1 sono una tipologia di nuclei galattici attivi caratterizzati dall’avere righe permesse più strette, se confrontate con quelle delle Seyfert 1, nonché dall’emissione intensa del ferro ionizzato. Solo circa il 7% di queste galassie è radio-loud e, tra questi rari oggetti, solamente in venti casi è stato osservato un flusso anche ad alte energie, nei raggi γ. Una di queste sorgenti è PKS 2004-447, il cui spettro nel regime ottico è stato elaborato ed analizzato nel corso di questa tesi. Sono stati ridotti i dati acquisiti tramite lo strumento FORS2 (utilizzato in questo caso in modalità long-slit spectroscopy) montato all’UT1, uno dei quattro telescopi che costituiscono il Very Large Telescope. Le osservazioni sono state condotte in sei notti, distribuite nell’arco di sei mesi, durante ciascuna delle quali sono stati acquisiti quattro spettri della sorgente in esame. Ognispettro è stato corretto per bias e flat field ed è stato poi calibrato in lunghezza d’onda e in flusso. Utilizzando ilsoftware IRAF, una volta ridotti i quattro spettri acquisiti per ogni notte, se ne è calcolato uno spettro medio. I sei spettri medi, così ottenuti, sono stati utilizzati per calcolare uno spettro mediano, dopo averli corretti per assorbimento galattico, pari a A(V ) = 0.019 mag, e per redshift, pari a z = 0.24, valore ottenuto misurando la posizione delle righe Hα, Hβ e [OIII]λ5007. Avendo lo spettro mediano un rapporto segnalerumore più elevato, è stato possibile utilizzarlo per ottenere il modello di emissione del ferro, che si è provveduto poi a sottrarre ai sei spettri medi. Affinché le misure relative alle righe di emissione, ad esempio di Hβ o di [OIII]λ5007, non fossero influenzate dalle diverse condizioni di osservazione durante le sei notti, ogni spettro è stato moltiplicato per un fattore ottenuto dal rapporto fra il flusso di [OIII]λ5007 misurato nello spettro mediano e quello dello spettro da riscalare. Si è scelta la riga dell’ossigeno poiché il tempo scala con cui la sua intensità varia è dell’ordine delle decine di anni e per questo motivo possiamo considerare invariato il suo flusso nel corso di alcuni mesi di osservazioni. Il flusso di Hβ, emessa in parte dalla BLR ed in parte dalla NLR, è stato misurato fittando l’osservabile con tre gaussiane, due per riprodurre la componente Hβ-broad ed una per riprodurre Hβ-narrow. La gaussiana usata per riprodurre Hβ-narrow è stata costruita ponendo il picco pari prima a 1/7, poi 1/10 ed infine 1/15 dell’intensità massima raggiunta da [OIII]λ5007 e fissandone la FWHM uguale a quella di [OIII]λ5007. Il motivo di quest’ultima scelta risiedeva nel fatto che il gas nella NLR ha una cinematica che causa l’allargamento delle righe di emissione tanto dell’ossigeno quanto dell’idrogeno presenti nella stessa regione. Poiché [OIII]λ5007 è presente solo nella NLR, la larghezza della riga da esso generata darà la velocità in tale regione. Mentre, per quanto riguarda la scelta dell’intensità del picco, si è fatto riferimento a quanto osservato nelle galassie con la sola NLR visibile, ovvero le Seyfert 2, in cui in media il rapporto risulta essere pari ad 1/10, con uno spread di valori che variano per l’appunto tra 1/7 ed 1/15. Poiché l’intervallo di valori èmolto ampio,si è provato a vedere come cambiassero i risultati finali supponendo questi tre tipi di rapporti. Successivamente, si sono misurati l’indice spettrale del continuo, il rapporto R4570 - ovvero il rapporto tra il flusso emesso dal ferro ionizzato e quello di Hβ-broad-, le larghezze equivalenti della riga Hβ e [OIII]λ5007 ed il flusso nel continuo a 5100 Å. Per finire, usando lo spettro mediano è stata calcolata la massa del buco nero supermassiccio al centro della galassia, che è risultato essere pari a 3.02 ·107M◉, nonché i rapporti di Eddington per le sei notti. I risultati rimarcano il problema ben più ampio, che riguarda in generale le γ-NLSy1, dell’avere una massa del SMBH troppo piccola per osservare un’emissione nei raggi γ, o, in altre parole, per avere un jet relativistico

Gas-phase Metallicity of Local Active Galactic Nuclei in the GASP and MaNGA Surveys: The Role of Ram Pressure Stripping

Growing evidence in support of a connection between active galactic nuclei (AGN) activity and the ram pressure stripping (RPS) phenomenon has been found both observationally and theoretically in the past decades. In this work, we further explore the impact of RPS on the AGN activity by estimating the gas-phase metallicity of nuclear regions and the mass–metallicity relation of galaxies at z ≤ 0.07 and with stellar masses $\mathrm{log}{M}_{* }/{M}_{\odot }\geqslant 9.0$ , either experiencing RPS or not. To measure oxygen abundances, we exploit Integral Field Spectroscopy data from the GASP and MaNGA surveys, photoionization models generated with the code Cloudy and the code Nebulabayes to compare models and observations. In particular, we build Cloudy models to reproduce line ratios induced by photoionization from stars, AGN, or a contribution of both. We find that the distributions of metallicity and [O iii ] λ 5007 luminosity of galaxies undergoing RPS are similar to the ones of undisturbed galaxies. Independently of the RPS, we do not find a correlation between stellar mass and AGN metallicity in the mass range $\mathrm{log}{M}_{* }/{M}_{\odot }\geqslant 10.4$ , while for the star-forming galaxies we observe the well-known mass–metallicity relation between $9.0\leqslant \mathrm{log}\ {M}_{* }/{M}_{\odot }\leqslant 10.8$ with a scatter mainly driven by the star formation rate and a plateau around $\mathrm{log}{M}_{* }/{M}_{\odot }\sim 10.5$ . The gas-phase metallicity in the nuclei of AGN hosts is enhanced with respect to those of star-forming galaxies by a factor of ∼ 0.05 dex regardless of the RPS

New Chemical Systems for the Removal of Calcareous Encrustations on Monumental Fountains: A Case Study of the Nymphaeum of Cerriglio

This study aims to compare the effects of some chemical agents on the removal of calcareous encrustations, which are characterized by the presence of both calcium and silicon. The experimentation was conducted during the conservation treatments of Cerriglio’s nymphaeum (Massa Lubrense, Naples, Italy). Tests were carried out in the laboratory on specimens and in situ to define the most efficient choice between several chelant agents, in the recovery of calcium and silicon, using ICP/OES and spectrocolorimetric and microscopic analyses

Peripheral markers of autophagy in polyglutamine diseases

Polyglutamine disorders are neurodegenerative diseases that share a CAG repeat expansion in the coding region, resulting in aggregated proteins that can be only degraded through aggrephagy. We measured the expression of autophagy genes in peripheral blood mononuclear cells of 20 patients with Huntington's disease (HD), 20 with spinocerebellar ataxia type 2 (SCA2), and 20 healthy individuals. HD patients showed increased expression of MAP1LC3B (+ 43%; p = 0.048), SQSTM1 (+ 49%; p = 0.002), and WDFY3 (+ 89%; p < 0.001). SCA2 patients had increased expression of WDFY3 (+ 69%; p < 0.001). We show that peripheral markers of autophagy are elevated in polyQ diseases, and this is particularly evident in HD

Exploring the AGN-ram pressure stripping connection in local clusters

Ram-pressure stripping by the intracluster medium (ICM) is one of the most advocated mechanisms that affect the properties of cluster galaxies. A recent study based on a small sample has found that many galaxies showing strong signatures of ram-pressure stripping also possess an active galactic nucleus (AGN), suggesting a possible correlation between the two phenomena. This result has not been confirmed by a subsequent study. Building upon previous findings, here we combine MUSE observations conducted within the GASP program and a general survey of the literature to robustly measure the AGN fraction in cluster's ram pressure stripped galaxies using BPT emission line diagrams. Considering a sample of 115 ram pressure stripped galaxies with stellar masses $geq 10^9 , M_{odot}$, we find an AGN fraction of $sim27$. This fraction strongly depends on stellar mass: it raises to 51% when only ram-pressure stripped galaxies of masses $M_* geq 10^{10} , M_{odot}$ are considered. We then investigate whether the AGN incidence is in excess in ram pressure stripped galaxies compared to non-stripped galaxies, using as comparison a sample of non-cluster galaxies observed by the survey MaNGA. Considering mass-matched samples, we find that the incidence of AGN activity is significantly higher (at a confidence level $>99.95$) when ram-pressure stripping is on act, supporting the hypothesis of an AGN-ram pressure connection

Exploring the AGN-ram pressure stripping connection in local clusters

Ram-pressure stripping by the intracluster medium (ICM) is one of the most advocated mechanisms that affect the properties of cluster galaxies. A recent study based on a small sample has found that many galaxies showing strong signatures of ram-pressure stripping also possess an active galactic nucleus (AGN), suggesting a possible correlation between the two phenomena. This result has not been confirmed by a subsequent study. Building upon previous findings, here we combine MUSE observations conducted within the GASP program and a general survey of the literature to robustly measure the AGN fraction in cluster's ram pressure stripped galaxies using BPT emission line diagrams. Considering a sample of 115 ram pressure stripped galaxies with stellar masses $geq 10^9 , M_{odot}$, we find an AGN fraction of $sim27$. This fraction strongly depends on stellar mass: it raises to 51% when only ram-pressure stripped galaxies of masses $M_* geq 10^{10} , M_{odot}$ are considered. We then investigate whether the AGN incidence is in excess in ram pressure stripped galaxies compared to non-stripped galaxies, using as comparison a sample of non-cluster galaxies observed by the survey MaNGA. Considering mass-matched samples, we find that the incidence of AGN activity is significantly higher (at a confidence level $>99.95$) when ram-pressure stripping is on act, supporting the hypothesis of an AGN-ram pressure connection