The mass and environmental dependence on the secular processes of AGN in terms of morphology, colour, and specific star-formation rate

Galaxy mass and environment play a major role in the evolution of galaxies. In the transition from star-forming to quenched galaxies, Active galactic nuclei (AGN) have also a principal action. However, the connections between these three actors are still uncertain. In this work we investigate the effects of stellar mass and the large-scale environment (LSS), on the fraction of optical nuclear activity in a population of isolated galaxies, where AGN would not be triggered by recent galaxy interactions or mergers. As a continuation of a previous work, we focus on isolated galaxies to study the effect of stellar mass and the LSS in terms of morphology (early- and late-type), colour (red and blue), and specific star formation rate (quenched and star-forming). To explore where AGN activity is affected by the LSS we fix the stellar mass into low- and high-mass galaxies. We use the tidal strength parameter to quantify their effects. We found that AGN is strongly affected by stellar mass in 'active' galaxies (namely late-type, blue, and star-forming), however it has no influence for 'quiescent' galaxies (namely early-type, red, and quenched), at least for masses down to $\rm 10^{10}\,[M_\odot]$. In relation to the LSS, we found an increment on the fraction of SFN with denser LSS in low-mass star forming and red isolated galaxies. Regarding AGN, we find a clear increment of the fraction of AGN with denser environment in quenched and red isolated galaxies, independently of the stellar mass. AGN activity would be 'mass triggered' in 'active' isolated galaxies. This means that AGN is independent of the intrinsic property of the galaxies, but on its stellar mass. On the other hand, AGN would be 'environment triggered' in 'quiescent' isolated galaxies, where the fraction of AGN in terms of sSFR and colour increases from void regions to denser LSS, independently of its stellar mass.Comment: 14 pages, 9 figures (11 pages and 6 figures without appendix), accepted for publication in Astronomy & Astrophysic

Isolated Galaxies versus Interacting Pairs with MaNGA

We present preliminary results of the spectral analysis on the radial distributions of the star formation history in both, a galaxy merger and a spiral isolated galaxy observed with MaNGA. We find that the central part of the isolated galaxy is composed by older stellar population ($\sim$2 Gyr) than in the outskirts ($\sim$7 Gyr). Also, the time-scale is gradually larger from 1 Gyr in the inner part to 3 Gyr in the outer regions of the galaxy. In the case of the merger, the stellar population in the central region is older than in the tails, presenting a longer time-scale in comparison to central part in the isolated galaxy. Our results are in agreement with a scenario where spiral galaxies are built from inside-out. In the case of the merger, we find evidence that interactions enhance star formation in the central part of the galaxy.Comment: 7 pages, 2 figures. Proceedings of the EWASS-2015 special session Sp3, accepted for publication in Special Issue "3D View on Interacting and Post-Interacting Galaxies from Clusters to Voids" of open access journal "Galaxies

Chemistry in isolation: High CCH/HCO+ line ratio in the AMIGA galaxy CIG 638

Multi-molecule observations towards an increasing variety of galaxies have been showing that the relative molecular abundances are affected by the type of activity. However, these studies are biased towards bright active galaxies, which are typically in interaction. We study the molecular composition of one of the most isolated galaxies in the local Universe where the physical and chemical properties of their molecular clouds have been determined by intrinsic mechanisms. We present 3 mm broad band observations of the galaxy CIG 638, extracted from the AMIGA sample of isolated galaxies. The emission of the J=1-0 transitions of CCH, HCN, HCO+, and HNC are detected. Integrated intensity ratios between these line are compared with similar observations from the literature towards active galaxies including starburst galaxies (SB), active galactic nuclei (AGN), luminous infrared galaxies (LIRG), and GMCs in M33. A significantly high ratio of CCH with respect to HCN, HCO+, and HNC is found towards CIG 638 when compared with all other galaxies where these species have been detected. This points to either an overabundance of CCH or to a relative lack of dense molecular gas as supported by the low HCN/CO ratio, or both. The data suggest that the CIG 638 is naturally a less perturbed galaxy where a lower fraction of dense molecular gas, as well as a more even distribution could explain the measured ratios. In this scenario the dense gas tracers would be naturally dimmer, while the UV enhanced CCH, would be overproduced in a less shielded medium.Comment: Letter accepted for publication in A&

The less significant role of large-scale environment than optical AGN in nearby, isolated elliptical galaxies

The formation and evolution of elliptical galaxies in low-density environments are less understood than classical elliptical galaxies in high-density environments. Isolated galaxies are defined as galaxies without massive neighbors within scales of galaxy groups. The effect of the environment at several Mpc scales on their properties has been barely explored. Here we study the role of large-scale environment in some physical properties of 573 isolated elliptical galaxies out to z=0.08. We use three environmental estimators of the large-scale structure within a projected radius of 5 Mpc around isolated galaxies: the tidal strength parameter, the projected density eta_k, and the distance to the fifth nearest neighbor galaxy. We find 80% of galaxies at lower densities correspond to 'red and dead' elliptical galaxies. Blue and red galaxies do not tend to be located in different environments according to eta_k. Almost all the isolated ellipticals in the densest large-scale environments are red or quenched, where a third of them are low-mass galaxies. The percentage of isolated elliptical galaxies located in the AGN region of the BPT diagram is 64%. We have identified 33 blue, star-forming isolated ellipticals using both color and sSFR. Half of them are star-forming nuclei in the BPT diagram, which is 5% of the galaxies in this diagram. The large-scale environment is not playing the primary role to determine the color or sSFR of isolated elliptical galaxies. The large-scale environment seems to be negligible from a stellar mass scale around 10^10.6 Msun, probably because of the dominant presence of AGN at higher masses. For lower masses, the processes of cooling and infall of gas from large scales are very inefficient in ellipticals. AGN might also be an essential ingredient to keep most of the low-mass isolated elliptical galaxies quenched.Comment: 15 pages, 6 figures (10 pages and 4 figures without appendices). Accepted for publication in A&

Effects of the environment on galaxies in the Catalogue of Isolated Galaxies: physical satellites and large scale structure

We aim to identify and quantify the effects of the satellite distribution around a sample of galaxies in the Catalogue of Isolated Galaxies (CIG), as well as the effects of the Large Scale Structure (LSS) using the SDSS-DR9. To recover the physically bound galaxies we focus on the satellites which are within the escape speed of each CIG galaxy. We also propose a more conservative method using the stacked Gaussian distribution of the velocity difference of the neighbours. The tidal strengths affecting the primary galaxy are estimated to quantify the effects of the local and LSS environments. We also define the projected number density parameter at the 5$^{\rm th}$ nearest neighbour to characterise the LSS around the CIG galaxies. Out of the 386 CIG galaxies considered in this study, at least 340 (88\% of the sample) have no physically linked satellite. Out of the 386 CIG galaxies, 327 (85\% of the sample) have no physical companion within a projected distance of 0.3 Mpc. The CIG galaxies are distributed following the LSS of the local Universe, although presenting a large heterogeneity in their degree of connection with it. A clear segregation appears between early-type CIG galaxies with companions and isolated late-type CIG galaxies. Isolated galaxies are in general bluer, with likely younger stellar populations and rather high star formation with respect to older, redder CIG galaxies with companions. Reciprocally, the satellites are redder and with an older stellar populations around massive early-type CIG galaxies, while they have a younger stellar content around massive late-type CIG galaxies. This suggests that the CIG is composed of a heterogeneous population of galaxies, sampling from old to more recent, dynamical systems of galaxies.Comment: 19 pages, 10 figures, 1 table, accepted for publication in Astronomy & Astrophysic

A ~ 12 kpc HI extension and other HI asymmetries in the isolated galaxy CIG 340 (IC 2487)

HI kinematic asymmetries are common in late-type galaxies irrespective of environment, although the amplitudes are strikingly low in isolated galaxies. As part of our studies of the HI morphology and kinematics in isolated late-type galaxies we have chosen several very isolated galaxies from the AMIGA sample for HI mapping. Here we present GMRT 21-cm HI line mapping of CIG 340 which was selected because its integrated HI spectrum has a very symmetric profile, Aflux = 1.03. Optical images of the galaxy hinted at a warped disk in contrast to the symmetric integrated HI spectrum profile. Our aim is to determine the extent to which the optical asymmetry is reflected in the resolved HI morphology and kinematics. GMRT observations reveal significant HI morphological asymmetries in CIG 340 despite it's overall symmetric optical form and highly symmetric HI spectrum. The most notable HI features are: 1) a warp in the HI disk (with an optical counterpart), 2) the HI north/south flux ratio = 1.32 is much larger than expected from the integrated HI spectrum profile and 3) a ~ 45" (12 kpc) HI extension, containing ~ 6% of the detected HI mass on the northern side of the disk. We conclude that in isolated galaxies a highly symmetric HI spectrum can mask significant HI morphological asymmetries. The northern HI extension appears to be the result of a recent perturbation (10^8 yr), possibly by a satellite which is now disrupted or projected within the disk. This study provides an important step in our ongoing program to determine the predominant source of HI asymmetries in isolated galaxies. For CIG 340 the isolation from major companions, symmetric HI spectrum, optical morphology and interaction timescales have allowed us to narrow the possible causes the HI asymmetries and identify tests to further constrain the source of the asymmetries.Comment: 10 page

SIT 45: An interacting, compact, and star-forming isolated galaxy triplet

The merging system SIT 45 (UGC 12589) is an unusual isolated galaxy triplet, consisting of three merging late-type galaxies, out of 315 systems in the SIT (SDSS-based catalogue of Isolated Triplets). The main aims of this work are to study its dynamical evolution and star formation history (SFH), as well as its dependence on its local and large-scale environment. To study its dynamics, parameters such as the velocity dispersion ($\sigma_{v}$), the harmonic radius ($R_{H}$), the crossing time ($H_0t_c$), and the virial mass ($M_{vir}$), along with the compactness of the triplet ($S$) were considered. To constrain the SFH, we used CIGALE to fit its observed spectral energy distribution using multi-wavelength data from the ultraviolet to the infrared. According to its SFH, SIT 45 presents star-formation, where the galaxies also present recent ($\sim$200 Myr) star-formation increase, indicating that this activity may have been triggered by the interaction. Its dynamical configuration suggests that the system is highly evolved in comparison to the SIT. However this is not expected for systems composed of star-forming late-type galaxies, based on observations in compact groups. We conclude that SIT 45 is a system of three interacting galaxies that are evolving within the same dark matter halo, where its compact configuration is a consequence of the on-going interaction, rather than due to a long-term evolution (as suggested from its $H_0t_c$ value). We consider two scenarios for the present configuration of the triplet, one where one of the members is a tidal galaxy, and another where this galaxy arrives to the system after the interaction. Both scenarios need further exploration. The isolated triplet SIT 45 is therefore an ideal system to study short timescale mechanisms ($\sim 10^8$ years), such as starbursts triggered by interactions which are more frequent at higher redshift.Comment: 13 pages, 7 figures, accepted for publication in Astronomy & Astrophysic

The Interstitial Lymphatic Peritoneal Mesothelium Axis in Portal Hypertensive Ascites: When in Danger, Go Back to the Sea

Portal hypertension induces a splanchnic and systemic low-grade inflammatory response that could induce the expression of three phenotypes, named ischemia-reperfusion, leukocytic, and angiogenic phenotypes.During the splanchnic expression of these phenotypes, interstitial edema, increased lymph flow, and lymphangiogenesis are produced in the gastrointestinal tract. Associated liver disease increases intestinal bacterial translocation, splanchnic lymph flow, and induces ascites and hepatorenal syndrome. Extrahepatic cholestasis in the rat allows to study the worsening of the portal hypertensive syndrome when associated with chronic liver disease. The splanchnic interstitium, the mesenteric lymphatics, and the peritoneal mesothelium seem to create an inflammatory pathway that could have a key pathophysiological relevance in the production of the portal hypertension syndrome complications. The hypothetical comparison between the ascitic and the amniotic fluids allows for translational investigation. From a phylogenetic point of view, the ancestral mechanisms for amniotic fluid production were essential for animal survival out of the aquatic environment. However, their hypothetical appearance in the cirrhotic patient is considered pathological since ultimately they lead to ascites development. But, the adult human being would take advantage of the potential beneficial effects of this “amniotic-like fluid” to manage the interstitial fluids without adverse effects when chronic liver disease aggravates

Efecto de la adición de melatonina en el medio de maduración y/o vitrificación de ovocitos sobre la producción in vitro de embriones bovinos

The effect of the addition of melatonin (Mt) on the maturation and / or vitrification of bovine oocytes on cleavage and subsequent embryonic development was evaluated. Oocyte-cumulus cell complexes (COCs) were obtained from creole cows by ovum pick up (OPU) and by follicular aspiration from abattoir ovaries (AO). From the pool of oocytes obtained from both sources, those with homogenous cytoplasm and three or more compact layers of cluster cells were selected. The selected COCs were randomly assigned to five treatments: T1, matured with Mt and vitrified without Mt; T2, matured and vitrified with Mt; T3, matured without Mt and vitrified with Mt; T4 (control) matured and vitrified without Mt; T5, matured without Mt and not vitrified. The concentration of Mt in the maturation and vitrification media was 0.01 μM (10-9 M). The oocytes were matured, vitrified, fertilized and the presumed zygotes cultured until day 7 post-fertilization in vitro. The data were analysed by logistic regression. Regardless of the origin of the oocytes, cleavage rate (C) and embryo production (EP) was similar between treatments. The C in the OPU oocytes was greater in T4, and the EP was similar between treatments. In AO, the results did not vary between treatment in C and EP. In conclusion, Mt reduced the C in oocytes collected by OPU, while it did not affect EP. In the AO oocyte source, the addition of Mt did not affect the C nor the EP.Se evaluó el efecto de la adición de melatonina (Mt) en el medio de maduración y/o de vitrificación de ovocitos bovinos sobre clivaje y posterior desarrollo embrionario. Los complejos ovocito-células del cúmulo (COCs) fueron obtenidos de vacas criollas mediante la técnica de aspiración transvaginal guiada por ultrasonografía (OPU) y de ovarios de matadero (OM). Del pool de ovocitos obtenidos de ambas fuentes se seleccionaron los que tenían citoplasma homogéneo y tres o más capas compactas de células del cúmulo. Los COCs seleccionados fueron asignados aleatoriamente a cinco tratamientos: T1, madurados con Mt y vitrificados sin Mt; T2, madurados y vitrificados con Mt; T3, madurados sin Mt y vitrificados con Mt; T4 (control) madurados y vitrificados sin Mt; T5, madurados sin Mt y no vitrificados. La concentración de Mt en los medios de maduración y vitrificación fue de 0.01 μM (10-9 M). Los ovocitos fueron madurados, vitrificados, fecundados y los presuntos cigotos cultivados hasta el día 7 pos-fecundación in vitro. Los datos fueron analizados por regresión logística. Independientemente del origen de los ovocitos, el porcentaje de clivaje (PC) y de producción de embriones (PIV) fue similar entre tratamientos. El PC en los ovocitos de OPU fue mayor en T4, y la PIV fue similar entre tratamientos. En los de OM, los resultados no variaron entre tratamiento en PC y PIV. En conclusión, la Mt redujo el PC en ovocitos colectados por OPU, mientras que no afectó la PIV. En los colectados de OM la adición de Mt no afectó el PC ni la PI