Space Telescope European Coordinating Facility

The hypothesized Planet Nine is thought to reside in the distant outer solar system, potentially explaining various anomalies in the orbits of extreme trans-Neptunian objects (ETNOs). In this work, we present a targeted observational search for Planet Nine in a field of approximately 98 square-degrees. This field is close to the highest probability region of finding Planet Nine, according to simulations, but poorly constrained by previous searches. Our observations and search methodology, based on the detection of parallax position shifts between consecutive nights, work well in these conditions. We provide 85% confidence exclusion limits for objects with Sloan r-band magnitudes brighter than between 21.0 and 21.4, with an average sensitivity limit of 21.3. No credible Planet Nine candidates were identified within this field and magnitude limits. A caveat to our approach is that it would miss a candidate if its position were affected by scattered light from bright stars in at least one of the nights. However, we estimate that the probability for this is very low, around 0.4%. We discuss several possible reasons for our Planet Nine non-detection. Our study complements prior searches, particularly those using archival survey data that are limited in the Galactic plane or at fainter brightness limits. While our consecutive-night observation approach offers high sensitivity to minimal motion, extending the search for Planet Nine to fainter magnitudes (which may be crucial, according to recent predictions), will require higher sensitivity instrumentation.

We present Hα observations of the inner region of the HR Carinae nebula. The inner nebula looks clumpy and material appears to be present only to the east of the central star. A jet-like filament stretches away from the central star to the southeast.

The WFC3 Infrared Spectroscopic Parallel Survey uses the Hubble Space Telescope (HST) infrared grism capabilities to obtain slitless spectra of thousands of galaxies over a wide redshift range including the peak of star formation history of the universe. We select a population of very strong emission-line galaxies with rest-frame equivalent widths (EWs) higher than 200 Å. A total of 176 objects are found over the redshift range 0.35 < z < 2.3 in the 180 arcmin^2 area that we have analyzed so far. This population consists of young and low-mass starbursts with high specific star formation rates (sSFR). After spectroscopic follow-up of one of these galaxies with Keck/Low Resolution Imaging Spectrometer, we report the detection at z = 0.7 of an extremely metal-poor galaxy with 12 + log(O/H) =7.47 ± 0.11. After estimating the active galactic nucleus fraction in the sample, we show that the high-EW galaxies have higher sSFR than normal star-forming galaxies at any redshift. We find that the nebular emission lines can substantially affect the total broadband flux density with a median brightening of 0.3 mag, with some examples of line contamination producing brightening of up to 1 mag. We show that the presence of strong emission lines in low-z galaxies can mimic the color-selection criteria used in the z ~ 8 dropout surveys. In order to effectively remove low-redshift interlopers, deep optical imaging is needed, at least 1 mag deeper than the bands in which the objects are detected. Without deep optical data, most of the interlopers cannot be ruled out in the wide shallow HST imaging surveys. Finally, we empirically demonstrate that strong nebular lines can lead to an overestimation of the mass and the age of galaxies derived from fitting of their spectral energy distribution (SED). Without removing emission lines, the age and the stellar mass estimates are overestimated by a factor of 2 on average and up to a factor of 10 for the high-EW galaxies. Therefore, the contribution of emission lines should be systematically taken into account in SED fitting of star-forming galaxies at all redshifts.

The influence of environment on the formation and evolution of early-type galaxies is, as yet, an unresolved issue. Constraints can be placed on models of early-type galaxy formation and evolution by examining their stellar populations as a function of environment. We present a catalogue of galaxies well suited to such an investigation. The magnitude-limited (<f><inline-fig> <link locator="mnras0409-1455-mu1"></inline-fig></f>) sample was drawn from four clusters (Coma, A1139, A3558 and A930 at 〈<it>z</it>〉= 0.04) and their surrounds. The catalogue contains luminosities, redshifts, velocity dispersions and Lick line strengths for 416 galaxies, of which 245 are classified as early types. Luminosity-weighted ages, metallicities and α-element abundance ratios have been estimated for 219 of these early types. We also outline the steps necessary for measuring fully calibrated Lick indices and estimating the associated stellar population parameters using up-to-date methods and stellar population models. In a subsequent paper we perform a detailed study of the stellar populations of early-type galaxies in clusters and investigate the effects of environment.

The work of astronomers is getting more complex and advanced as the progress of computer development occurs. With improved computing capabilities and increased data flow, more sophisticated software is required in order to interpret, and fully exploit, astronomic data. However, it is not possible for every astronomer to also be a software specialist. As history has shown, the work of scientists always becomes increasingly specialised, and we here argue in favour of another, at least partial, split between "programmers" and "interpreters". In this presentation we outline our vision for a new approach and symbiosis between software specialists and scientists, and present its advantages along with a simple test case.

Abstract We have used the Low Resolution Imaging Spectrograph on the W. M. Keck I telescope to obtain spatially resolved spectroscopy of a small sample of six ‘post-starburst’ and three ‘dusty-starburst’ galaxies in the rich cluster CL 0016+16 at z=0.55. We use this to measure radial profiles of the Hδ and [OII]λ3727 lines which are diagnostic probes of the mechanisms that give rise to the abrupt changes in star formation rates in these galaxies. In the post-starburst sample we are unable to detect any radial gradients in the Hδ line equivalent width — although one galaxy exhibits a gradient from one side of the galaxy to the other. The absence of Hδ gradients in these galaxies is consistent with their production via interaction with the intracluster medium; however, our limited spatial sampling prevents us from drawing robust conclusions. All members of the sample have early-type morphologies, typical of post-starburst galaxies in general, but lack the high incidence of tidal tails and disturbances seen in local field samples. This argues against a merger origin and adds weight to a scenario where truncation by the intra-cluster medium is at work. The post-starburst spectral signature is consistent over the radial extent probed with no evidence of [OII]λ3727 emission and strong Hδ absorption at all radii, i.e. the post-starburst classification is not an aperture effect. In contrast the ‘dusty-starburst’ sample shows a tendency for a central concentration of [OII]λ3727 emission. This is most straightforwardly interpreted as the consequence of a central starburst. However, other possibilities exist such as a non-uniform dust distribution (which is expected in such galaxies) and/or a non-uniform starburst age distribution. The members of the sample exhibit late-type and irregular morphologies.

Abstract The Space Telescope European Co-ordinating Facility (ST-ECF), in the context of space-astronomy (ESA) and in close collaboration with ground-based astronomy (ESO), has pioneered the use of physical instrument models for instrument calibration and forward data analysis. The methodology provides real insight into the physical properties of the signal chain and therefore offers a high degree of predictability for the behavior of instruments and the measurements generated.KeywordsDispersion SolutionSignal ChainLine ListCalibration ItemReal InsightThese keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

We present GALEX far (FUV) and near (NUV) ultraviolet imaging of 34 nearby early-type galaxies from the SAURON representative sample of 48 E/S0 galaxies, all of which have ground-based optical imaging from the MDM Observatory. The surface brightness profiles of nine galaxies show regions with blue UV-optical colours suggesting recent star formation. Five of these show blue integrated UV-optical colours that set them aside in the NUV integrated colour-magnitude relation. They also have other properties confirming they have had recent star formation, in particular H_beta absorption higher than expected for a quiescent population and a higher CO detection rate. NUV-blue galaxies are generally drawn from the lower stellar velocity dispersion and thus lower dynamical mass part of the sample. We have also constructed the first UV Fundamental Planes and show that NUV blue galaxies bias the slopes and increase the scatters. If they are eliminated the fits get closer to expectations from the virial theorem. Although our analysis is based on a limited sample, it seems that a dominant fraction of the tilt and scatter of the UV Fundamental Planes is due to the presence of young stars in preferentially low-mass early-type galaxies. Interestingly, the UV-optical radial colour profiles reveal a variety of behaviours, with many galaxies showing signs of recent star formation, a central UV-upturn phenomenon, smooth but large-scale age and metallicity gradients, and in many cases a combination of these. In addition, FUV-NUV and FUV-V colours even bluer than those normally associated with UV-upturn galaxies are observed at the centre of some quiescent galaxies. Four out of the five UV-upturn galaxies are slow rotators. These objects should thus pose interesting challenges to stellar evolutionary models of the UV-upturn.

In this paper we present for the first time high spatial resolution K-band maps of the central kinematical and near-infrared spectral properties of the giant cD galaxy in the Fornax cluster, NGC 1399. We confirm the presence of a central velocity dispersion dip within radius < 0.2 seen in previous long-slit studies. Our velocity dispersion maps give evidence for a non-symmetric structure in this central area by showing three sigma peaks to the north-east, south-east and west of the galaxy centre. Additionally we measure near-IR line strength indices at unprecedented spatial resolution in NGC 1399. The most important features we observe in our 2-dimensional line strength maps are drops in Na I and CO(2-0) line strength in the nuclear region of the galaxy, coinciding spatially with the drop in sigma. The observed line strength and velocity dispersion changes suggest a scenario where the centre of NGC 1399 harbours a dynamically cold subsystem with a distinct stellar population.

Sampo is a 3 year project that began in January 2005. It is led by ESO and conducted by a software development team from Finland as an in-kind contribution to joining ESO. The goal of the project is to assess the needs of the ESO community in the area of data reduction and analysis environments and to create pilot software products that illustrate critical steps along the road to a new system.