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Studies of the kinematics of NGC 1407 have revealed complex kinematical structure, consisting of the outer galaxy, an embedded disc within a radius of $\sim60$ arcsec, and a kinematically decoupled core (KDC) with a radius of less than 30arcsec. However, the size of the KDC and the amplitude of the kinematic misalignment it induces have not yet been determined. In this paper, we explore the properties of the KDC using observations from the MUSE Integral Field Spectrograph to map out the kinematics in the central arcminute of NGC 1407. Velocity and kinemetry maps of the galaxy reveal a twist of $\sim$148 degree in the central $10$ arcseconds of the galaxy, and the higher-order moments of the kinematics reveal that within the same region, this slowly-rotating galaxy displays no net rotation. Analysis of the stellar populations across the galaxy found no evidence of younger stellar populations in the region of the KDC, instead finding uniform age and super-solar $\alpha$-enhancement across the galaxy, and a smoothly decreasing metallicity gradient with radius. We therefore conclude that NGC 1407 contains a triaxial, kiloparsec-scale KDC with distinct kinematics relative to the rest of the galaxy, and which is likely to have formed through either a major merger or a series of minor mergers early in the lifetime of the galaxy. With a radius of $\sim$5 arcseconds or $\sim0.6$ kpc, NGC 1407 contains the smallest KDC mapped by MUSE to date in terms of both its physical and angular size., Comment: 9 pages, 5 figures, Published in MNRAS

We present a study of the inner (out to $\sim$1 R$_{\mathrm{eff}}$) stellar populations of 9 shell galaxies. We derive stellar population parameters from long slit spectra by both analyzing the Lick indices of the galaxies and by fitting Single Stellar Population model spectra to the full galaxy spectra. The results from the two methods agree reasonably well. Many of the shell galaxies in our sample appear to have lower central $\mathrm{Mg}_{2}$ index values than non-shell galaxies of the same central velocity dispersion, which is likely due to a past interaction event. Our shell galaxy sample shows a relation between central metallicity and velocity dispersion that is consistent with previous samples of non-shell galaxies. Analyzing the metallicity gradients in our sample, we find an average metallicity gradient of -0.16$\pm$0.10 dex per decade in radius. We compare this with formation models to constrain the merging history of shell galaxies. We argue that our galaxies likely have undergone major mergers in their past but it is unclear whether the shells formed from these events or from separate minor mergers. Additionally, we find evidence for young stellar populations ranging in age from 500 Myr to 4--5 Gyr in four of the galaxies, allowing us to speculate on the age of the shells. For NGC 5670, we use a simple dynamical model to find the time required to produce the observed distribution of shells to be consistent with the age of the young subpopulation, suggesting that the shells likely formed from the same event that led to the young subpopulation., Comment: Submitted to MNRAS. 16 pages, 7 figures. V1

We present a study of the physical properties of JO201, a unique disk galaxy with extended tails undergoing extreme ram-pressure stripping as it moves through the massive cluster Abell 85 at supersonic speeds mostly along the line of sight. JO201 was observed with MUSE as part of the GASP programme. In a previous paper (GASP II) we studied the stellar and gas kinematics. In this paper we present emission-line ratios, gas-phase metallicities and ages of the stellar populations across the galaxy disk and tails. We find that while the emission at the core of the galaxy is dominated by an active galactic nucleus (AGN), the disk is composed of star-forming knots surrounded by excited diffuse gas. The collection of star-forming knots presents a metallicity gradient steadily decreasing from the centre of the galaxy outwards, and the ages of the stars across the galaxy show that the tails formed, 17 pages, 12 figures

The origin of ultracompact dwarfs (UCDs), a class of compact stellar systems discovered two decades ago, still remains a matter of debate. Recent discoveries of central supermassive black holes in UCDs likely inherited from their massive progenitor galaxies provide support for the tidal stripping hypothesis. At the same time, on statistical grounds, some massive UCDs might be representatives of the high luminosity tail of the globular cluster luminosity function. Here we present a detection of a $3.3^{+1.4}_{-1.2}\times10^6\,M_{\odot}$ black hole ($1\sigma$ uncertainty) in the centre of the UCD3 galaxy in the Fornax cluster, that corresponds to 4 per cent of its stellar mass. We performed isotropic Jeans dynamical modelling of UCD3 using internal kinematics derived from adaptive optics assisted observations with the SINFONI spectrograph and seeing limited data collected with the FLAMES spectrograph at the ESO VLT. We rule out the zero black hole mass at the $3\sigma$ confidence level when adopting a mass-to-light ratio inferred from stellar populations. This is the fourth supermassive black hole found in a UCD and the first one in the Fornax cluster. Similarly to other known UCDs that harbour black holes, UCD3 hosts metal rich stars enhanced in $\alpha$-elements that supports the tidal stripping of a massive progenitor as its likely formation scenario. We estimate that up to 80 per cent of luminous UCDs in galaxy clusters host central black holes. This fraction should be lower for UCDs in groups, because their progenitors are more likely to be dwarf galaxies, which do not tend to host central black holes., Comment: Accepted in MNRAS, 11 pages, 8 figures, 1 table

It is well known that galaxies falling into clusters can experience gas stripping due to ram-pressure by the intra-cluster medium (ICM). The most spectacular examples are galaxies with extended tails of optically-bright stripped material known as "jellyfish". We use the first large homogeneous compilation of jellyfish galaxies in clusters from the WINGS and OmegaWINGS surveys, and follow-up MUSE observations from the GASP MUSE programme to investigate the orbital histories of jellyfish galaxies in clusters and reconstruct their stripping history through position vs. velocity phase- space diagrams. We construct analytic models to define the regions in phase-space where ram-pressure stripping is at play. We then study the distribution of cluster galaxies in phase-space and find that jellyfish galaxies have on average higher peculiar velocities (and higher cluster velocity dispersion) than the overall population of cluster galaxies at all clustercentric radii, which is indicative of recent infall into the cluster and radial orbits. In particular, the jellyfish galaxies with the longest gas tails reside very near the cluster cores (in projection) and are moving at very high speeds, which coincides with the conditions of the most intense ram-pressure. We conclude that many of the jellyfish galaxies seen in clusters likely formed via fast (~1- 2 Gyr), incremental, outside-in ram-pressure stripping during first infall into the cluster in highly radial orbits., Comment: 14 pages, 9 figures, MNRAS in press

When supermassive black holes at the center of galaxies accrete matter (usually gas), they give rise to highly energetic phenomena named Active Galactic Nuclei (AGN). A number of physical processes have been proposed to account for the funneling of gas towards the galaxy centers to feed the AGN. There are also several physical processes that can strip gas from a galaxy, and one of them is ram pressure stripping in galaxy clusters due to the hot and dense gas filling the space between galaxies. We report the discovery of a strong connection between severe ram pressure stripping and the presence of AGN activity. Searching in galaxy clusters at low redshift, we have selected the most extreme examples of jellyfish galaxies, which are galaxies with long tentacles of material extending for dozens of kpc beyond the galaxy disk. Using the MUSE spectrograph on the ESO Very Large Telescope, we find that 6 out of the 7 galaxies of this sample host a central AGN, and two of them also have galactic-scale AGN ionization cones. The high incidence of AGN among the most striking jellyfishes may be due to ram pressure causing gas to flow towards the center and triggering the AGN activity, or to an enhancement of the stripping caused by AGN energy injection, or both. Our analysis of the galaxy position and velocity relative to the cluster strongly supports the first hypothesis, and puts forward ram pressure as another, yet unforeseen, possible mechanism for feeding the central supermassive black hole with gas., published in Nature, Vol.548, Number 7667, pag.304

We present the nature of 50 hard X-ray emitting objects unveiled through an optical spectroscopy campaign performed at seven telescopes in the northern and southern hemispheres. These objects were detected with the Burst Alert Telescope (BAT) instrument onboard the Swift satellite and listed as of unidentified nature in the 54-month Palermo BAT catalogue. In detail, 45 sources in our sample are identified as active galactic nuclei of which, 27 are classified as type 1 (with broad and narrow emission lines) and 18 are classified as type 2 (with only narrow emission lines). Among the broad-line emission objects, one is a type 1 high-redshift quasi-stellar object, and among the narrow-line emission objects, one is a starburst galaxy, one is a X-ray bright optically normal galaxy, and one is a low ionization nuclear emission line region. We report 30 new redshift measurements, 13 confirmations and 2 more accurate redshift values. The remaining five objects are galactic sources: three are Cataclismic Variables, one is a X-ray Binary probably with a low mass secondary star, and one is an active star. Based on observations obtained from the following observatories: Cerro Tololo Interamerican Observatory (Chile); Astronomical Observatory of Bologna in Loiano (Italy); Observatorio Astronómico Nacional (San Pedro Mártir, Mexico); Radcliffe telescope of the South African Astronomical Observatory (Sutherland, South Africa); Sloan Digital Sky Survey; Observatorio del Roque de los Muchachos of the Instituto de Astrofísica de Canarias (Canary Islands, Spain) and New Technology Telescope (NTT) of La Silla Observatory, Chile.

SPIFFI is an AO-fed integral field spectrograph operating as part of SINFONI on the VLT, which will be upgraded and reused as SPIFFIER in the new VLT instrument ERIS. In January 2016, we used new technology developments to perform an early upgrade to optical subsystems in the SPIFFI instrument so ongoing scientific programs can make use of enhanced performance before ERIS arrives in 2020. We report on the upgraded components and the performance of SPIFFI after the upgrade, including gains in throughput and spatial and spectral resolution. We show results from re-commissioning, highlighting the potential for scientific programs to use the capabilities of the upgraded SPIFFI. Finally, we discuss the additional upgrades for SPIFFIER which will be implemented before it is integrated into ERIS., Comment: 20 pages, 12 figures. Proceedings from SPIE Astronomical Telescopes and Instrumentation 2016

We present a deep [O II] emission-line survey of faint galaxies (22.5< KAB

We studied the optical counterpart of the intermediate-mass black hole candidate HLX-1 in ESO 243-49. We used a set of Very Large Telescope imaging observations from 2010 November, integrated by Swift X-ray data from the same epoch. We measured standard Vega brightnesses U = 23.89 +/- 0.18 mag, B = 25.19 +/- 0.30 mag, V = 24.79 +/- 0.34 mag and R = 24.71 +/- 0.40 mag. Therefore, the source was ~1 mag fainter in each band than in a set of Hubble Space Telescope images taken a couple of months earlier, when the X-ray flux was a factor of 2 higher. We conclude that during the 2010 September observations, the optical counterpart was dominated by emission from an irradiated disk (which responds to the varying X-ray luminosity), rather than by a star cluster around the black hole (which would not change). We modelled the Comptonized, irradiated X-ray spectrum of the disk, and found that the optical luminosity and colours in the 2010 November data are still consistent with emission from the irradiated disk, with a characteristic outer radius r_{out} ~ 2800 r_{in} ~ 10^{13} cm and a reprocessing fraction ~ 2 x 10^{-3}. The optical colours are also consistent with a stellar population with age

The first observations of laser guide star photons Raman-scattered by air molecules above the Very Large Telescope (VLT) were reported in June 2017. The initial detection came from the Multi-Unit Spectroscopic Explorer (MUSE) optical integral field spectrograph, following the installation of the 4 Laser Guide Star Facility (4LGSF) on the Unit Telescope 4 (UT4) of the VLT. In this Letter, we delve further into the symbiotic relationship between the 4LGSF laser guide star system, the UT4 telescope, and MUSE by monitoring the spectral contamination of MUSE observations by Raman photons over a 27 month period. This dataset reveals that dust particles deposited on the primary and tertiary mirrors of UT4 -- responsible for a reflectivity loss of ~8% at 6000{\AA} -- contribute (60$\pm5)% to the laser line fluxes detected by MUSE. The flux of Raman lines, contaminating scientific observations acquired with optical spectrographs, thus provides a new, non-invasive means to monitor the evolving scatter properties of the mirrors of astronomical telescopes equipped with laser guide star systems., Comment: 5 pages, 3 figures, 1 table, accepted for publication in A&A Letters

We use a K-selected (22.5 < K_AB < 24.0) sample of dwarf galaxies (8.4 < log(M*/Msun) < 10) at 0.89, Comment: Accepted for publication in MNRAS Letters. 6 pages, 2 figures

We present a possible star formation and chemical evolutionary history for two early-type galaxies NGC 1407 and NGC 1400. They are the two brightest galaxies of the NGC 1407 (or Eridanus-A) group, one of the 60 groups studied as part of the Group Evolution Multi-wavelength Study (GEMS). Our analysis is based on new high signal-to-noise spatially resolved integrated spectra obtained at the ESO 3.6m telescope, out to 0.6 (NGC 1407) and 1.3 (NGC 1400) effective radii. Using Lick/IDS indices we estimate luminosity-weighted ages, metallicities and $��$-element abundance ratios. Colour radial distributions from HST/ACS and Subaru Suprime-Cam multi-band wide-field imaging are compared to colours predicted from spectroscopically determinated ages and metallicities using single stellar population models. The galaxies formed over half of their mass in a single short-lived burst of star formation (> 100 M(sun)/year) at redshift z>5. This likely involved an outside-in mechanism with supernova-driven galactic winds, as suggested by the flatness of the alpha-element radial profiles and the strong negative metallicity gradients. Our results support the predictions of the revised version of the monolithic collapse model for galaxy formation and evolution. We speculate that, since formation the galaxies have evolved quiescently and that we are witnessing the first infall of NGC 1400 in the group., 14 pages, 9 tables, 6 figures, Accepted for publication in MNRAS

We present radial stellar population parameters for a subsample of 12 galaxies from the 36 isolated early-type galaxies of Reda et al. Using new long-slit spectra, central values and radial gradients for the stellar age, metallicity [Z/H] and alpha-element abundance [E/Fe] are measured. Similarly, the central stellar population parameters are derived for a further 5 isolated early-type galaxies using their Lick indices from the literature. On average, the seventeen isolated galaxies have mean central [Z/H]o and [E/Fe]o of 0.29+/-0.03 and 0.17+/-0.03 respectively and span a wide range of ages from 1.7 to 15 Gyrs. We find that isolated galaxies follow similar scaling relations between central stellar population parameters and galaxy velocity dispersion to their counterparts in high density environments. However, we note a tendency for isolated galaxies to have slightly younger ages, higher [Z/H] and lower [E/Fe]. Such properties are qualitatively consistent with the expectation of an extended star formation history for galaxies in lower density environments. Generally we measure constant age and [E/Fe] radial gradients. We find that the age gradients anti-correlate with the central galaxy age. Metallicity gradients range from near zero to strongly negative. For our high mass galaxies metallicity gradients are shallower with increasing mass. Such behaviour is not predicted in dissipational collapse models but might be expected in multiple mergers. The metallicity gradients correlate with the central age and metallicity, as well as to the age gradients. In conclusion, our stellar population data for isolated galaxies are more compatible with an extended merger/accretion history than early dissipative collapse., The paper contains 8 figures and 5 tables. Accepted for publication in the MNRAS

Here we present new measurements of effective radii, surface brightnesses and internal velocity dispersions for 23 isolated early-type galaxies. The photometric properties are derived from new multi-colour imaging of 10 galaxies, whereas the central kinematics for 7 galaxies are taken from forthcoming work by Hau & Forbes. These are supplemented with data from the literature. We reproduce the colour-magnitude and Kormendy relations and strengthen the result of Paper I that isolated galaxies follow the same photometric relations as galaxies in high density environments. We also find that some isolated galaxies reveal fine structure indicative of a recent merger while others appear undisturbed. We examine the Fundamental Plane in both traditional R_e, mu_e and sigma space and also kappa-space. Most isolated galaxies follow the same Fundamental Plane tilt and scatter for galaxies in high density environments. However, a few galaxies notably deviate from the plane in the sense of having smaller M/L ratios. This can be understood in terms of their younger stellar populations, which are presumably induced by a gaseous merger. Overall, isolated galaxies have similar properties to those in roups and clusters with a slight enhancement in the frequency of recent mergers/interactions., Comments:11 pages, 7 Postscript figures, 2 JPEG figures. Accepted for publication in MNRAS

We confront predictions of the currently popular theories for dE formation and evolution with the observed position of dEs in $\log L_B$ vs. $\log \sigma$ , $\log L_B$ vs. $\log R_{\rm e}$ , $\log L_B$ vs. $\log I_{\rm e}$ , and $\log R_{\rm e}$ vs. $\log I_{\rm e}$ diagrams and in the ( $\log \sigma,\log R_{\rm e},\log I_{\rm e}$ ) parameter space in which bright and intermediate-luminosity elliptical galaxies and bulges of spirals define a Fundamental Plane (FP). We show that the dE sequences in the various univariate diagrams are disjunct from those traced by bright and intermediate-luminosity elliptical galaxies and bulges of spirals. It appears that semi-analytical models (SAMs) that incorporate quiescent star formation with an essentially $z$ -independent star-formation efficiency, combined with post-merger starbursts and the dynamical response after supernova-driven gas-loss, are able to reproduce the position of the dEs in the various univariate and bivariate diagrams.

We present near-infrared K-band imaging of a large sample of candidate merger remnant galaxies and Hickson Compact Group ellipticals. We derive light profile indices, effective radii and surface brightnesses, as well as total K-band magnitudes. We find that the light distributions of the merger remnant candidates are consistent with those of ‘normal’ ellipticals, and scatter around a mean profile index of (1/n) = 0.20. Many of our sample galaxies have surface brightness profiles that are not well described by a de Vaucouleurs law (1/n = 0.25), and we discuss the implications of this on the derived total magnitudes. Comparing the total K magnitudes calculated by extrapolating a de Vaucouleurs profile and those derived using a generalized S´

We present photometric and kinematic evidence for the presence of stellar disks, seen practically edge-on, in two Fornax dwarf galaxies, FCC204 (dS0(6)) and FCC288 (dS0(7)). This is the first time such structures have been identified in Fornax dwarfs. FCC2088 has only a small bulge and a bright flaring and slightly warped disk that can be traced out to 23" from the center (2.05 kpc for H_0=75 km/s/Mpc). FCC204's disk can be traced out to 20" (1.78 kpc). This galaxy possesses a large bulge. These results can be compared to the findings of Jerjen et al. (2000) and Barazza et al. (2002) who discovered nucleated dEs with spiral and bar features in the Virgo Cluster.

We present Hα+[Nii] narrow-band imaging of FCC046 and FCC207, two dwarf el-lipticals (dES) in the Fornax Cluster. B-R and B-I color-maps clearly show signs ofdust-absorption in FCC207. FCC046 has a very bright blue nucleus, offset by about1.1 ′′ with respect to the outer isophotes. FCC046 was classified as a non-nucleateddE4 so the presence of its nucleus came as a surprise. Moreover, FCC046 shows apronounced lopsided shape. Given that FCC046 is an isolated galaxy, it is unlikelythat an encounter caused this asymmetry. The emitting regions differ considerablybetween the two galaxies. Whereas FCC207 has only one central emission region,FCC046 also contains fainter emission regions. Based on broad-band colours, its dis-turbed shape and its very bright nucleus, FCC046 is akin to the class of amorphousdwarfs. The central emission regions of both galaxies are barely resolved under see-ing conditions of FWHM≈ 0.8 ′′ and we estimate their diameters at about 60 pc.Their Hα luminosities can be explained as photo-ionisation by post-AGB stars inan old population. Some of the fainter extended emission regions in FCC046 are re-solved and have diameters of the order of 50−150 pc and Hα luminosities of the orderof 10

In this paper we present a combined analysis of data obtained with the Hubble Space Telescope (HST), Very Large Telescope (VLT), and Swift X-ray telescope (XRT) of the intermediate mass black hole ESO 243-49 HLX-1 that were taken 2 months apart between September and November 2010. Previous separate analyses of these data found that they were consistent with an irradiated accretion disc with contribution from either a very young or very old stellar population, and also indicated that the optical flux of the HLX-1 counterpart could be variable. Such variability could only be attributed to a varying accretion disc, so simultaneous analysis of all data sets should break the degeneracies in the model fits. We thus simultaneously fit the broad-band spectral energy distribution (SED) from near-infrared through to X-ray wavelengths of the two epochs of data with a model consisting of an irradiated accretion disc and a stellar population. We show that this combined analysis rules out an old stellar population, finding that the SED is dominated by emission from an accretion disc with moderate reprocessing in the outer disc around an intermediate mass black hole imbedded in a young (20 Myr) stellar cluster with a mass of 1E5 Msun. We also place an upper limit on the mass of an additional hidden old stellar population of 1E6 Msun. However, optical r-band observations of HLX-1 obtained with the Gemini-South telescope covering part of the decay from a later X-ray outburst are consistent with constant optical flux, indicating that the observed variability between the HST and VLT observations could be spurious caused by differences in the background subtraction applied to the two optical data sets. In this scenario the contribution of the stellar population, and thus the stellar mass of the cluster, may be higher (abridged)., 9 pages, 4 figures, 3 tables, accepted for publication in MNRAS on 8th October 2013

We present MUSE observations of ESO137-001, a spiral galaxy infalling towards the center of the massive Norma cluster at z~0.0162. During the high-velocity encounter of ESO137-001 with the intracluster medium, a dramatic ram-pressure stripping event gives rise to an extended gaseous tail, traced by our MUSE observations to >30 kpc from the galaxy center. By studying the H-alpha surface brightness and kinematics in tandem with the stellar velocity field, we conclude that ram pressure has completely removed the interstellar medium from the outer disk, while the primary tail is still fed by gas from the inner regions. Gravitational interactions do not appear to be a primary mechanism for gas removal. The stripped gas retains the imprint of the disk rotational velocity to ~20 kpc downstream, without a significant gradient along the tail, which suggests that ESO137-001 is fast moving along a radial orbit in the plane of the sky. Conversely, beyond ~20 kpc, a greater degree of turbulence is seen, with velocity dispersion up to >100 km/s. For a model-dependent infall velocity of ~3000 km/s, we conclude that the transition from laminar to turbulent flow in the tail occurs on timescales >6.5 Myr. Our work demonstrates the terrific potential of MUSE for detailed studies of how ram-pressure stripping operates on small scales, providing a deep understanding of how galaxies interact with the dense plasma of the cluster environment., 10 pages, 6 figures. MNRAS in press

NGC 3311 is the central cD galaxy of the Hydra I cluster. We use globular clusters around NGC 3311, combined with kinematical data of the galaxy itself, to investigate the dark matter distribution in the central region of Hydra I. Radial velocities of 118 bright globular clusters, based on VLT/VIMOS mask spectroscopy, are used to calculate velocity dispersions which are well defined out to 100 kpc. NGC 3311 is the most distant galaxy for which this kind of study has been performed. We also determine velocity dispersions of the stellar component from long slit spectroscopy out to 20 kpc. Moreover, we present a new photometric model for NGC 3311 in the V-band. We search for a dark halo which in the context of a spherical Jeans model. We also compare the radial velocity distributions of globular clusters and planetary nebulae. The projected stellar velocity dispersion rises from 185 km/s to 350 km/s at a radius of 20 kpc. The globular cluster dispersion rises as well from 500 km/s at 10 kpc to about 800 km/s at 100 kpc, comparable to the velocity dispersion of the cluster galaxies. A dark matter halo with a core reproduces well the velocity dispersions of stars and globular clusters simultaneously under isotropy. The central stellar velocity dispersions predicted by cosmological NFW halos are less good representations, while the globular clusters allow a wide range of halo parameters. A suspected radial anisotropy of the stellar population aggravates the deviations. However, we find discrepancies with previous kinematical data, which we cannot resolve and may indicate a more complicated velocity pattern. Although one cannot conclusively demonstrate that the dark matter halo of NGC 3311 has a core rather than a cusp, a core seems to be preferred by the present data. A more complete velocity field and an analysis of the anisotropy is required to reach firm conclusions., Comment: 8 pages, 5 figures, abstract abridged, accepted for publication in A&A

This is the first paper of a series focused on investigating the star formation and evolutionary history of the two early-type galaxies NGC 1407 and NGC 1400. They are the two brightest galaxies of the NGC 1407 (or Eridanus-A) group, one of the 60 groups studied as part of the Group Evolution Multi-wavelength Study (GEMS). Here we present new high signal-to-noise long-slit spectroscopic data obtained at the ESO 3.6m telescope and high-resolution multi-band imaging data from the HST/ACS and wide-field imaging from Subaru Suprime-Cam. We spatially resolved integrated spectra out to 0.6 (NGC 1407) and 1.3 (NGC 1400) effective radii. The radial profiles of the kinematic parameters v(rot), sigma, h3 and h4 are measured. The surface brightness profiles are fitted to different galaxy light models and the colour distributions analysed. The multi-band images are modelled to derive isophotal shape parameters and residual galaxy images. The parameters from the surface brightness profile fitting are used to estimate the mass of the possible central supermassive black hole in NGC 1407. The galaxies are found to be rotationally supported and to have a flat core in the surface brightness profiles. Elliptical isophotes are observed at all radii and no fine structures are detected in the residual galaxy images. From our results we can also discard a possible interaction between NGC 1400, NGC 1407 and the group intergalactic medium. We estimate a mass of 1.03x10^9 M(sun) for the supermassive black hole in NGC 1407 galaxy., 11 pages, 6 tables, 6 figures, Accepted for publication in MNRAS

We have obtained near-infrared imaging of 58 galaxy groups, in the redshift range 0.1, Comment: Accepted for publication in MNRAS. 13 pages mn2e style, with 11 figures and 4 tables

Ellipticals in very low density environments are extremely rare but hold important clues about galaxy formation and evolution. We present results of an investigation of their internal dynamics. We observe a dichotomy in kinematic properties similar to that in normal ellipticals. We compare the positions of isolated ellipticals with respect to the Fundamental Plane of normal ellipticals and find that they fall onto it, with the exception of NGC 2865. This shows that isolated ellipticals are structurally similar to normal ellipticals, and do not have very young ages, although some have signs of past mergers or interactions. To search for other articles by the author(s) go to: http://adsabs.harvard.edu/abstract_service.html

We have investigated the stellar kinematics of two brightest cluster galaxies (BCGs) to large distances from the cluster centre. In both galaxies, the velocity dispersion rises with radius. Orbital anisotropy is ruled out as the cause and we conclude that the kinematics in the outer parts of BCGs are dark matter dominated. This result contrasts with the current problem for intermediate luminosity ellipticals, which appear to have less dark matter than predicted by CDM. Combining the present results with our previous work, the fraction of BCGs with outwardly rising dispersions (∼ 60%) is much higher than that found previously (∼ 7%) from the inner parts of BCGs. We argue that this phenomenon may be more common than previously thought. The agreement with radial trends expected for a smooth galaxy/cluster transition, and the lack of dependence on cD/BCG dominance and cluster environment, suggest that the outwardly rising dispersion is a genuine response of the stars to the underlying cluster potential. There is evidence that BCG in Abell 2063 is not at the centre of the cluster potential. 1. The "dearth of dark matter" problem in intermediate luminosity ellipticals Are elliptical galaxies good places to look for dark matter? In the Cold Dark Matter (CDM) paradigm, elliptical galaxies are expected to possess a massive dark halo made up of subhalos of hierarchically merged galaxies, and their kinematics in the outer parts are expected to be dominated by the dark matter potential. Recent observational results on intermediate-luminosity (and mass) ellipticals seem to challenge this assumption. Mea- surements, using Planetary Nebulae, of the radial dispersion profiles of 3 intermediate- luminosity ellipticals to large radii show that they decrease with distance from the galaxy centre, with little evidence of dark matter (Romanowsky et al. 2003). The combined kine- matics of the stars and PNe can be described well by constant M/L ratio models, with M/L lower than CDM predictions and consistent with a stellar M/L ratio. For one of these galaxies (NGC 3379), the globular cluster kinematics also support this finding (Bridges et al. 2003, Beasley et al. 2004 in preparation). This so-called "dearth of dark matter" problem is one of the current challenges for CDM (Binney 2004).

The well-known recurrent nova T Pyx has brightened by 7 magnitudes, starting on 2011 April 14, its first eruption since 1966. T Pyx is unique amongst recurrent novæ in being surrounded by a nebula formed of material ejected during previous eruptions. The latest eruption therefore offers the rare opportunity to observe a light echo sweeping through the existing shell, and a new one forming. The sudden exposure of the existing shell to high-energy light is expected to result in a change of the dust morphology as well as in the part destruction of molecules. We observe this process in the near- and mid-IR during several epochs using ESO's VLT instruments Sinfoni, Visir and Isaac. Unfortunately, in the data analysed so far we only have a tentative detection in Brα from the shell, so might in the end have to be content with upper limits for the emission from the various molecular bands and ionised lines.