We examine the dependence of the fraction of galaxies containing pseudobulges on environment for a flux limited sample of $\sim$5000 SDSS galaxies. Wehave separated bulges into classical and pseudo bulge categories based on theirposition on the Kormendy diagram. Pseudo bulges are thought to be formed byinternal processes and are a result of secular evolution in galaxies. Weattempt to understand the dependence of secular evolution on environment andmorphology. Dividing our sample of disc+bulge galaxies based on groupmembership into three categories: central and satellite galaxies in groups andisolated field galaxies, we find that pseudo bulge fraction is almost equal forsatellite and field galaxies. Fraction of pseudo bulge hosts in centralgalaxies is almost half of the fraction of pseudo bulges in satellite and fieldgalaxies. This trend is also valid when only galaxies are considered onlyspirals or S0. Using the projected fifth nearest neighbour density as measureof local environment, we look for the dependence of pseudo bulge fraction onenvironmental density. Satellite and field galaxies show very weak or nodependence of pseudo bulge fraction on environment. However, fraction of pseudobulges hosted by central galaxies decreases with increase in localenvironmental density. We do not find any dependence of pseudo bulge luminosityon environment. Our results suggest that the processes that differentiate thebulge types are a function of environment while processes responsible for theformation of pseudo bulges seem to be independent of environment.

We describe the structural, stellar population and gas properties of thenearest Ultra Diffuse Galaxy (UDG) discovered so far: UGC2162 (z=0.00392;R$_{e,g}$=1.7$(\pm$0.2) kpc; $\mu_g(0)$=24.4$\pm$0.1 mag/arcsec$^2$;g-i=0.33$\pm$0.02). This galaxy, located at a distance of 12.3($\pm$1.7) Mpc,is a member of the M77 group. UGC2162 has a stellar mass of$\sim$2($^{+2}_{-1}$)$\times$10$^7$ M$_\odot$ and is embedded within a cloud ofHI gas $\sim$10 times more massive: $\sim$1.9($\pm$0.6)$\times$10$^8$M$_\odot$. Using the width of its HI line as a dynamical proxy, the enclosedmass within the inner R$\sim$5 kpc is $\sim$4.6($\pm$0.8)$\times$10$^9$M$_\odot$ (i.e. M/L$\sim$200). The estimated virial mass from the cumulativemass curve is $\sim$8($\pm$2)$\times$10$^{10}$ M$_\odot$. Ultra-deep imagingfrom the IAC Stripe82 Legacy Project show that the galaxy is irregular and hasmany star forming knots, with a gas-phase metallicity around one-third of thesolar value. Its estimated Star Formation Rate (SFR) is $\sim$0.01M$_\odot$/yr. This SFR would double the stellar mass of the object in $\sim$2Gyr. If the object were to stop forming stars at this moment, after a passiveevolution, its surface brightness would become extremely faint:$\mu_g(0)$$\sim$27 mag/arcsec$^2$ and its size would remain largeR$_{e,g}$$\sim$ 1.8 kpc. Such faintness would make it almost undetectable tomost present-day surveys. This suggests that there could be an importantpopulation of M$_{\star}$$\sim$10$^7$ M$_\odot$ "dark galaxies" in richenvironments (depleted of HI gas) waiting to be discovered by current andfuture ultra-deep surveys.

The total mass M_GCS in the globular cluster (GC) system of a galaxy isempirically a near-constant fraction of the total mass M_h = M_bary + M_dark ofthe galaxy, across a range of 10^5 in galaxy mass. This trend is radicallyunlike the strongly nonlinear behavior of total stellar mass M_star versus M_h.We discuss extensions of this trend to two more extreme situations: (a) entireclusters of galaxies, and (b) the Ultra-Diffuse Galaxies (UDGs) recentlydiscovered in Coma and elsewhere. Our calibration of the ratio \eta_M = M_GCS /M_h from normal galaxies, accounting for new revisions in the adoptedmass-to-light ratio for GCs, now gives \eta_M = 2.9 \times 10^{-5} as the meanabsolute mass fraction. We find that the same ratio appears valid for galaxyclusters and UDGs. Estimates of \eta_M in the four clusters we examine tend tobe slightly higher than for individual galaxies, butmore data and betterconstraints on the mean GC mass in such systems are needed to determine if thisdifference is significant. We use the constancy of \eta_M to estimate totalmasses for several individual cases; for example, the total mass of the MilkyWay is calculated to be M_h = 1.1 \times 10^{12} M_sun. Physical explanationsfor the uniformity of \eta_M are still descriptive, but point to a picture inwhich massive, dense star clusters in their formation stages were relativelyimmune to the feedback that more strongly influenced lower-density regionswhere most stars form.

We present the first systematic investigation of the existence, spatialdistribution, and kinematics of warm ionized gas as traced by the [O II] 3727AAemission line in 74 of the most massive galaxies in the local Universe. All ofour galaxies have deep integral field spectroscopy from the volume- andmagnitude-limited MASSIVE survey of early-type galaxies with stellar masslog(M_*/M_sun) > 11.5 (M_K < -25.3 mag) and distance D < 108 Mpc. Of the 74galaxies in our sample, we detect warm ionized gas in 28, which yields a globaldetection fraction of 38\pm6% down to a typical [O II] equivalent width limitof 2AA. MASSIVE fast rotators are more likely to have gas than MASSIVE slowrotators with detection fractions of 80\pm10% and 28\pm6%, respectively. Thespatial extents span a wide range of radii (0.6 - 18.2 kpc; 0.1 - 4R_e), andthe gas morphologies are diverse, with 17/28 = 61\pm9% being centrallyconcentrated, 8/28 = 29\pm9% exhibiting clear rotation out to several kpc, and3/28 = 11\pm6% being extended but patchy. Three out of four fast rotators showkinematic alignment between the stars and gas, whereas the two slow rotatorswith robust kinematic measurements available exhibit kinematic misalignment.Our inferred warm ionized gas masses are roughly ~10^5M_sun. The emission lineratios and radial equivalent width profiles are generally consistent withexcitation of the gas by the old underlying stellar population. We exploredifferent gas origin scenarios for MASSIVE galaxies and find that a variety ofphysical processes are likely at play, including internal gas recycling,cooling out of the hot gaseous halo, and gas acquired via mergers.

CONTEXT. A set of 20 extremely red galaxies at 2.5<z<3.8 with photometricfeatures of old passive-evolving galaxies without dust, with stellar masses of~10^{11} M_sun, have colors that could be related to passive-evolving galaxieswith mean ages larger than 1 Gyr. This suggests they have been formed, onaverage, when the Universe was very young (<1 Gyr). AIMS. We provide new estimates for the stellar content of these 20 galaxies,with a deeper analysis for two of them that includes spectroscopy. METHODS. We obtained, with the GRANTECAN-10.4 m, ultraviolet rest-framespectra of two galaxies and analyzed them together with photometric data. Theremaining 18 galaxies are analyzed only with photometry. We fit the data withmodels of a single-burst stellar population (SSP), combinations of two SSPs, aswell as with extended star formation. RESULTS. Fits based on one SSP do not provide consistent results for the blueand red wavelengths. Moreover, the absence in the spectra of a break at ~2,000angstroms indicates that a rather young component is necessary. Using two SSPswe can match the photometric and spectroscopic data, with the bulk of thestellar population being very old (several Gyr) and the remaining contribution(<5% of stellar mass fraction) from a young, likely residual star formationcomponent with age <~0.1 Gyr. Exponentially decaying extended star formationmodels improve slightly the fits with respect to the single burst model, butthey are considerably worse than the two SSP based fits, further supporting theresidual star formation scenario. CONCLUSIONS. The fact that one SSP cannot match these early-type galaxieshighlights the limitations for the use of age estimators based on single linesor breaks, such as the Balmer break used in cosmic chronometers, thusquestioning this approach for cosmological purposes.