@article{RichterNuzaFoxetal.2017, author = {Richter, Philipp and Nuza, S. E. and Fox, Andrew J. and Wakker, Bart P. and Lehner, N. and Ben Bekhti, Nadya and Fechner, Cora and Wendt, Martin and Howk, J. Christopher and Muzahid, S. and Ganguly, R. and Charlton, Jane C.}, title = {An HST/COS legacy survey of high-velocity ultraviolet absorption in the}, series = {Astronomy and astrophysics : an international weekly journal}, volume = {607}, journal = {Astronomy and astrophysics : an international weekly journal}, publisher = {EDP Sciences}, address = {Les Ulis}, issn = {1432-0746}, doi = {10.1051/0004-6361/201630081}, pages = {90}, year = {2017}, abstract = {Context. The Milky Way is surrounded by large amounts of diffuse gaseous matter that connects the stellar body of our Galaxy with its large-scale Local Group (LG) environment. Aims. To characterize the absorption properties of this circumgalactic medium (CGM) and its relation to the LG we present the so-far largest survey of metal absorption in Galactic high-velocity clouds (HVCs) using archival ultraviolet (UV) spectra of extragalactic background sources. The UV data are obtained with the Cosmic Origins Spectrograph (COS) onboard the Hubble Space Telescope (HST) and are supplemented by 21 cm radio observations of neutral hydrogen. Methods. Along 270 sightlines we measure metal absorption in the lines of Si II, Si III, C II, and C IV and associated H I 21 cm emission in HVCs in the velocity range vertical bar v(LSR)vertical bar = 100-500 km s(-1). With this unprecedented large HVC sample we were able to improve the statistics on HVC covering fractions, ionization conditions, small-scale structure, CGM mass, and inflow rate. For the first time, we determine robustly the angular two point correlation function of the high-velocity absorbers, systematically analyze antipodal sightlines on the celestial sphere, and compare the HVC absorption characteristics with that of damped Lyman alpha absorbers (DLAs) and constrained cosmological simulations of the LG (CLUES project).}, language = {en} } @article{WisotzkiBaconBlaizotetal.2016, author = {Wisotzki, Lutz and Bacon, Roland and Blaizot, J. and Brinchmann, Jarle and Herenz, Edmund Christian and Schaye, Joop and Bouche, Nicolas and Cantalupo, Sebastiano and Contini, Thierry and Carollo, C. M. and Caruana, Joseph and Courbot, J. -B. and Emsellem, E. and Kamann, S. and Kerutt, Josephine Victoria and Leclercq, F. and Lilly, S. J. and Patricio, V. and Sandin, C. and Steinmetz, Matthias and Straka, Lorrie A. and Urrutia, Tanya and Verhamme, A. and Weilbacher, Peter Michael and Wendt, Martin}, title = {Extended Lyman alpha haloes around individual high-redshift galaxies revealed by MUSE}, series = {Science}, volume = {587}, journal = {Science}, publisher = {EDP Sciences}, address = {Les Ulis}, issn = {1432-0746}, doi = {10.1051/0004-6361/201527384}, pages = {27}, year = {2016}, abstract = {We report the detection of extended Ly alpha emission around individual star-forming galaxies at redshifts z = 3-6 in an ultradeep exposure of the Hubble Deep Field South obtained with MUSE on the ESO-VLT. The data reach a limiting surface brightness (1 sigma) of similar to 1 x 10(-19) erg s(-1) cm(-2) arcsec(-2) in azimuthally averaged radial profiles, an order of magnitude improvement over previous narrowband imaging. Our sample consists of 26 spectroscopically confirmed Ly alpha-emitting, but mostly continuum-faint (m(AB) greater than or similar to 27) galaxies. In most objects the Ly alpha emission is considerably more extended than the UV continuum light. While five of the faintest galaxies in the sample show no significantly detected Ly alpha haloes, the derived upper limits suggest that this is due to insufficient S/N. Ly alpha haloes therefore appear to be ubiquitous even for low-mass (similar to 10(8)-10(9) M-circle dot) star-forming galaxies at z > 3. We decompose the Ly alpha emission of each object into a compact component tracing the UV continuum and an extended halo component, and infer sizes and luminosities of the haloes. The extended Ly alpha emission approximately follows an exponential surface brightness distribution with a scale length of a few kpc. While these haloes are thus quite modest in terms of their absolute sizes, they are larger by a factor of 5-15 than the corresponding rest-frame UV continuum sources as seen by HST. They are also much more extended, by a factor similar to 5, than Ly alpha haloes around low-redshift star-forming galaxies. Between similar to 40\% and greater than or similar to 90\% of the observed Ly alpha flux comes from the extended halo component, with no obvious correlation of this fraction with either the absolute or the relative size of the Ly alpha halo. Our observations provide direct insights into the spatial distribution of at least partly neutral gas residing in the circumgalactic medium of low to intermediate mass galaxies at z > 3.}, language = {en} } @article{TurnerSchayeCrainetal.2016, author = {Turner, Monica L. and Schaye, Joop and Crain, Robert A. and Theuns, Tom and Wendt, Martin}, title = {Observations of metals in the z approximate to 3.5 intergalactic medium and comparison to the EAGLE simulations}, series = {Monthly notices of the Royal Astronomical Society}, volume = {462}, journal = {Monthly notices of the Royal Astronomical Society}, publisher = {Oxford Univ. Press}, address = {Oxford}, issn = {0035-8711}, doi = {10.1093/mnras/stw1816}, pages = {2440 -- 2464}, year = {2016}, abstract = {We study the z approximate to 3.5 intergalactic medium (IGM) by comparing new, high-quality absorption spectra of eight QSOs with < z(QSO)> = 3.75, to virtual observations of the Evolution and Assembly of Galaxies and their Environments (EAGLE) cosmological hydrodynamical simulations. We employ the pixel optical depth method and uncover strong correlations between various combinations of H I, C III, C IV, Si III, Si IV, and O VI. We find good agreement between many of the simulated and observed correlations, including tau(O) (VI) (tau(H) (I)). However, the observed median optical depths for the tau(C) (IV) (tau(H) (I)) and tau(Si) (IV) (tau(H) (I)) relations are higher than those measured from the mock spectra. The discrepancy increases from up to approximate to 0.1 dex at tau(H) (I) = 1 to approximate to 1 dex at tau(H) (I) = 10(2), where we are likely probing dense regions at small galactocentric distances. As possible solutions, we invoke (a) models of ionizing radiation softened above 4 Ryd to account for delayed completion of He II reionization; (b) simulations run at higher resolution; (c) the inclusion of additional line broadening due to unresolved turbulence; and (d) increased elemental abundances; however, none of these factors can fully explain the observed differences. Enhanced photoionization of H I by local sources, which was not modelled, could offer a solution. However, the much better agreement with the observed O VI(H I) relation, which we find probes a hot and likely collisionally ionized gas phase, indicates that the simulations are not in tension with the hot phase of the IGM, and suggests that the simulated outflows may entrain insufficient cool gas.}, language = {en} } @article{BoucheFinleySchroetteretal.2016, author = {Bouche, Nicolas and Finley, H. and Schroetter, I. and Murphy, M. T. and Richter, Philipp and Bacon, Roland and Contini, Thierry and Richard, J. and Wendt, Martin and Kamann, S. and Epinat, Benoit and Cantalupo, Sebastiano and Straka, Lorrie A. and Schaye, Joop and Martin, C. L. and Peroux, C. and Wisotzki, Lutz and Soto, K. and Lilly, S. and Carollo, C. M. and Brinchmann, Jarle and Kollatschny, W.}, title = {POSSIBLE SIGNATURES OF A COLD-FLOW DISK FROM MUSE USING A z similar to 1 GALAXY-QUASAR PAIR TOWARD SDSS J1422-0001}, series = {The astrophysical journal : an international review of spectroscopy and astronomical physics}, volume = {820}, journal = {The astrophysical journal : an international review of spectroscopy and astronomical physics}, publisher = {IOP Publ. Ltd.}, address = {Bristol}, issn = {0004-637X}, doi = {10.3847/0004-637X/820/2/121}, pages = {1872 -- 1882}, year = {2016}, abstract = {We use a background quasar to detect the presence of circumgalactic gas around a z = 0.91 low-mass star-forming galaxy. Data from the new Multi Unit Spectroscopic Explorer (MUSE) on the Very Large Telescope show that the galaxy has a dust-corrected star formation rate (SFR) of 4.7 +/- 2.0. M-circle dot yr(-1), with no companion down to 0.22 M-circle dot yr(-1) (5 sigma) within 240 h(-1) kpc ("30"). Using a high-resolution spectrum of the background quasar, which is fortuitously aligned with the galaxy major axis (with an azimuth angle alpha of only 15 degrees), we find, in the gas kinematics traced by low-ionization lines, distinct signatures consistent with those expected for a "cold-flow disk" extending at least 12 kpc (3 x R-1/2). We estimate the mass accretion rate M-in to be at least two to three times larger than the SFR, using the geometric constraints from the IFU data and the H (I) column density of log N-H (I)/cm(-2) similar or equal to 20.4 obtained from a Hubble Space Telescope/COS near-UV spectrum. From a detailed analysis of the low-ionization lines (e.g., Zn II, Cr II, Ti II, MnII, Si II), the accreting material appears to be enriched to about 0.4 Z(circle dot) (albeit with large uncertainties: log Z/Z(circle dot) = -0.4 +/- 0.4), which is comparable to the galaxy metallicity (12 + log O/H = 8.7 +/- 0.2), implying a large recycling fraction from past outflows. Blueshifted Mg II and Fe II absorptions in the galaxy spectrum from the MUSE data reveal the presence of an outflow. The Mg II and Fe II absorption line ratios indicate emission infilling due to scattering processes, but the MUSE data do not show any signs of fluorescent Fe II* emission.}, language = {en} } @article{HusserKamannDreizleretal.2016, author = {Husser, Tim-Oliver and Kamann, Sebastian and Dreizler, Stefan and Wendt, Martin and Wulff, Nina and Bacon, Roland and Wisotzki, Lutz and Brinchmann, Jarle and Weilbacher, Peter Michael and Roth, Martin M. and Monreal-Ibero, Ana}, title = {MUSE crowded field 3D spectroscopy of over 12 000 stars in the globular cluster NGC 6397 I. The first comprehensive HRD of a globular cluster}, series = {Nucleic acids research}, volume = {588}, journal = {Nucleic acids research}, publisher = {EDP Sciences}, address = {Les Ulis}, issn = {1432-0746}, doi = {10.1051/0004-6361/201526949}, pages = {14}, year = {2016}, abstract = {Aims. We demonstrate the high multiplex advantage of crowded field 3D spectroscopy with the new integral field spectrograph MUSE by means of a spectroscopic analysis of more than 12 000 individual stars in the globular cluster NGC 6397. Methods. The stars are deblended with a point spread function fitting technique, using a photometric reference catalogue from HST as prior, including relative positions and brightnesses. This catalogue is also used for a first analysis of the extracted spectra, followed by an automatic in-depth analysis via a full-spectrum fitting method based on a large grid of PHOENIX spectra. Results. We analysed the largest sample so far available for a single globular cluster of 18 932 spectra from 12 307 stars in NGC 6397. We derived a mean radial velocity of v(rad) = 17.84 +/- 0.07 km s(-1) and a mean metallicity of [Fe/H] = -2.120 +/- 0.002, with the latter seemingly varying with temperature for stars on the red giant branch (RGB). We determine Teff and [Fe/H] from the spectra, and log g from HST photometry. This is the first very comprehensive Hertzsprung-Russell diagram (HRD) for a globular cluster based on the analysis of several thousands of stellar spectra, ranging from the main sequence to the tip of the RGB. Furthermore, two interesting objects were identified; one is a post-AGB star and the other is a possible millisecond-pulsar companion.}, language = {en} } @article{KamannHusserBrinchmannetal.2016, author = {Kamann, S. and Husser, T. -O. and Brinchmann, Jarle and Emsellem, E. and Weilbacher, Peter Michael and Wisotzki, Lutz and Wendt, Martin and Krajnovic, D. and Roth, M. M. and Bacon, Roland and Dreizler, S.}, title = {MUSE crowded field 3D spectroscopy of over 12 000 stars in the globular cluster NGC 6397}, series = {Tectonophysics : international journal of geotectonics and the geology and physics of the interior of the earth}, volume = {588}, journal = {Tectonophysics : international journal of geotectonics and the geology and physics of the interior of the earth}, publisher = {EDP Sciences}, address = {Les Ulis}, issn = {1432-0746}, doi = {10.1051/0004-6361/201527065}, pages = {12}, year = {2016}, abstract = {We present a detailed analysis of the kinematics of the Galactic globular cluster NGC 6397 based on more than similar to 18 000 spectra obtained with the novel integral field spectrograph MUSE. While NGC 6397 is often considered a core collapse cluster, our analysis suggests a flattening of the surface brightness profile at the smallest radii. Although it is among the nearest globular clusters, the low velocity dispersion of NGC 6397 of < 5 km s(-1) imposes heavy demands on the quality of the kinematical data. We show that despite its limited spectral resolution, MUSE reaches an accuracy of 1 km s(-1) in the analysis of stellar spectra. We find slight evidence for a rotational component in the cluster and the velocity dispersion profile that we obtain shows a mild central cusp. To investigate the nature of this feature, we calculate spherical Jeans models and compare these models to our kinematical data. This comparison shows that if a constant mass-to-light ratio is assumed, the addition of an intermediate-mass black hole with a mass of 600 M-circle dot brings the model predictions into agreement with our data, and therefore could be at the origin of the velocity dispersion profile. We further investigate cases with varying mass-to-light ratios and find that a compact dark stellar component can also explain our observations. However, such a component would closely resemble the black hole from the constant mass-to-light ratio models as this component must be confined to the central similar to 5 ' of the cluster and must have a similar mass. Independent constraints on the distribution of stellar remnants in the cluster or kinematic measurements at the highest possible spatial resolution should be able to distinguish the two alternatives.}, language = {en} } @article{SchroetterBoucheWendtetal.2016, author = {Schroetter, I. and Bouche, Nicolas and Wendt, Martin and Contini, Thierry and Finley, H. and Pello, R. and Bacon, Roland and Cantalupo, Sebastiano and Marino, Raffaella Anna and Richard, J. and Lilly, S. J. and Schaye, Joop and Soto, K. and Steinmetz, Matthias and Straka, Lorrie A. and Wisotzki, Lutz}, title = {MUSE GAS FLOW AND WIND (MEGAFLOW). I. FIRST MUSE RESULTS ON BACKGROUND QUASARS}, series = {The astrophysical journal : an international review of spectroscopy and astronomical physics}, volume = {833}, journal = {The astrophysical journal : an international review of spectroscopy and astronomical physics}, publisher = {IOP Publ. Ltd.}, address = {Bristol}, issn = {0004-637X}, doi = {10.3847/1538-4357/833/1/39}, pages = {17}, year = {2016}, abstract = {The physical properties of galactic winds are one of the keys to understand galaxy formation and evolution. These properties can be constrained thanks to background quasar lines of sight (LOS) passing near star-forming galaxies (SFGs). We present the first results of the MusE GAs FLOw and Wind survey obtained from two quasar fields, which have eight Mg II absorbers of which three have rest equivalent width greater than 0.8 angstrom. With the new Multi Unit Spectroscopic Explorer (MUSE) spectrograph on the Very Large Telescope (VLT), we detect six (75\%) Mg II host galaxy candidates within a radius of 30. from the quasar LOS. Out of these six galaxy-quasar pairs, from geometrical argument, one is likely probing galactic outflows, where two are classified as "ambiguous,"two are likely probing extended gaseous disks and one pair seems to be a merger. We focus on the wind-pair and constrain the outflow using a high-resolution quasar spectra from the Ultraviolet and Visual Echelle Spectrograph. Assuming the metal absorption to be due to ga;s flowing out of the detected galaxy through a cone along the minor axis, we find outflow velocities in the order of approximate to 150 km s(-1) (i.e., smaller than the escape velocity) with a loading factor, eta = M-out/SFR, of approximate to 0.7. We see evidence for an open conical flow, with a low-density inner core. In the future, MUSE will provide us with about 80 multiple galaxy-quasar pairs in two dozen fields.}, language = {en} } @article{MonrealIberoWeilbacherWendtetal.2015, author = {Monreal-Ibero, Ana and Weilbacher, Peter Michael and Wendt, Martin and Selman, Fernando and Lallement, Rosine and Brinchmann, Jarle and Kamann, Sebastian and Sandin, Christer}, title = {Towards DIB mapping in galaxies beyond 100 Mpc A radial profile of the lambda 5780.5 diffuse interstellar band in AM1353-272 B}, series = {Astronomy and astrophysics : an international weekly journal}, volume = {576}, journal = {Astronomy and astrophysics : an international weekly journal}, publisher = {EDP Sciences}, address = {Les Ulis}, issn = {0004-6361}, doi = {10.1051/0004-6361/201525854}, pages = {4}, year = {2015}, abstract = {Context. Diffuse interstellar bands (DIBs) are non-stellar weak absorption features of unknown origin found in the spectra of stars viewed through one or several clouds of the interstellar medium (ISM). Research of DIBs outside the Milky Way is currently very limited. In particular, spatially resolved investigations of DIBs outside of the Local Group are, to our knowledge, inexistent. Aims. In this contribution, we explore the capability of the high-sensitivity integral field spectrograph, MUSE, as a tool for mapping diffuse interstellar bands at distances larger than 100 Mpc. Methods. We used MUSE commissioning data for AM1353-272 B, the member with the highest extinction of the Dentist's Chair, an interacting system of two spiral galaxies. High signal-to-noise spectra were created by co-adding the signal of many spatial elements distributed in a geometry of concentric elliptical half-rings. Results. We derived decreasing radial profiles for the equivalent width of the lambda 5780.5 DIB both in the receding and approaching side of the companion galaxy up to distances of similar to 4.6 kpc from the centre of the galaxy. The interstellar extinction as derived from the Ha/H beta line ratio displays a similar trend, with decreasing values towards the external parts. This translates into an intrinsic correlation between the strength of the DIB and the extinction within AM1353-272 B, consistent with the currently existing global trend between these quantities when using measurements for Galactic and extragalactic sightlines. Conclusions. It seems feasible to map the DIB strength in the Local Universe, which has up to now only been performed for the Milky Way. This offers a new approach to studying the relationship between DIBs and other characteristics and species of the ISM in addition to using galaxies in the Local Group or sightlines towards very bright targets outside the Local Group.}, language = {en} } @article{WeilbacherMonrealIberoKollatschnyetal.2015, author = {Weilbacher, Peter Michael and Monreal-Ibero, Ana and Kollatschny, Wolfram and Ginsburg, Adam and McLeod, Anna F. and Kamann, Sebastian and Sandin, Christer and Palsa, Ralf and Wisotzki, Lutz and Bacon, Roland and Selman, Fernando and Brinchmann, Jarle and Caruana, Joseph and Kelz, Andreas and Martinsson, Thomas and Pecontal-Rousset, Arlette and Richard, Johan and Wendt, Martin}, title = {A MUSE map of the central Orion Nebula (M 42)}, series = {Astronomy and astrophysics : an international weekly journal}, volume = {582}, journal = {Astronomy and astrophysics : an international weekly journal}, publisher = {EDP Sciences}, address = {Les Ulis}, issn = {1432-0746}, doi = {10.1051/0004-6361/201526529}, pages = {16}, year = {2015}, abstract = {We present a new integral field spectroscopic dataset of the central part of the Orion Nebula (M 42), observed with the MUSE instrument at the ESO VLT. We reduced the data with the public MUSE pipeline. The output products are two FITS cubes with a spatial size of similar to 5'9 x 4'9 (corresponding to similar to 0.76 x 0.63 pc(2)) and a contiguous wavelength coverage of 4595 ... 9366 angstrom, spatially sampled at 0 ''.2. We provide two versions with a sampling of 1.25 angstrom and 0.85 angstrom in dispersion direction. Together with variance cubes these files have a size of 75 and 110 GiB on disk. They are the largest integral field mosaics to date in terms of information content. We make them available for use in the community. To validate this dataset, we compare world coordinates, reconstructed magnitudes, velocities, and absolute and relative emission line fluxes to the literature values and find excellent agreement. We derive a 2D map of extinction and present de-reddened flux maps of several individual emission lines and of diagnostic line ratios. We estimate physical properties of the Orion Nebula, using the emission line ratios [N II] and [S III] (for the electron temperature T-e) and [S II] and [Cl III] (for the electron density N-e), and show 2D images of the velocity measured from several bright emission lines.}, language = {en} } @article{EvansMurphyWhitmoreetal.2014, author = {Evans, T. M. and Murphy, M. T. and Whitmore, J. B. and Misawa, T. and Centurion, Martin and Lopez, S. and Martins, C. J. A. P. and Molaro, P. and Petitjean, P. and Rahmani, H. and Srianand, R. and Wendt, Martin}, title = {The UVES Large Program for testing fundamental physics - III. Constraints on the fine-structure constant from three telescopes}, series = {Monthly notices of the Royal Astronomical Society}, volume = {445}, journal = {Monthly notices of the Royal Astronomical Society}, number = {1}, publisher = {Oxford Univ. Press}, address = {Oxford}, issn = {0035-8711}, doi = {10.1093/mnras/stu1754}, pages = {128 -- 150}, year = {2014}, language = {en} }