TY  - JOUR
A1  - Wendt, Martin
A1  - Senftleben, Nele
A1  - Gros, Patrick
A1  - Schmitt, Thomas
T1  - Coping with environmental extremes
BT  - population ecology and behavioural adaptation of Erebia pronoe, an Alpine butterfly species
JF  - Insects : open access journal
N2  - Simple Summary:& nbsp;High alpine meadows are home to numerous endemic butterfly species. A combination of climate change and changes in agricultural practices has led to a severe decline in many species. A seemingly unaffected representative of this habitat is Erebia pronoe. We studied the behaviour, resource use and population structure of this species to explain its resilience and estimate its future survival potential. This species shows pronounced protandry in combination with serial eclosion. Males were significantly more active and mobile and were also caught significantly more often than females, resulting in a pronounced shift in sex ratio in the predicted population structure. The adults use a wide range of nectar plants and establish homeranges in areas of high habitat quality. Thus, Erebia pronoe adults use a wide array of resources combined with a slight specialisation to avoid niche overlap with closely related species. The resulting ecological flexibility seems to be an adaptation to unpredictable environmental conditions, which should be the result of a long-lasting adaptation process. Moreover, the combination of opportunism and modest specialisation should also be a good basis for coping with future changes caused by climate and land-use change.</p> <br /> <br></p> <br /> A mark-recapture study of the nominotypical Erebia pronoe in the Alps was conducted to survey its ecological demands and characteristics. Population structure analysis revealed a combination of protandry (one-week earlier eclosion of males) and serial eclosion. Significant differences between both sexes were found in population density (males: 580/ha & PLUSMN; 37 SE; females: 241/ha & PLUSMN; 66 SE), sex-ratio (2.4) and behaviour (57.7 vs. 11.9% flying). Both sexes used a wide range of nectar plants (Asteraceae, 77.3%; Dipsacaceae, 12.3%; Gentianaceae, 9.7%). The use of nectar plants shows a non-specific spectrum, which, however, completely avoids overlap with the locally co-occurring species Erebia nivalis. Movement patterns show the establishment of homeranges, which significantly limits the migration potential. Due to its broad ecological niche, E. pronoe will probably be able to react plastically to the consequences of climate change. The formation of high population densities, the unconcerned endangerment status, the unspecific resource spectrum and the sedentary character of the species make E. pronoe a potential indicator of the quality and general resource occurrence of alpine rupicolous grasslands.
KW  - mark-release-recapture
KW  - movement patterns
KW  - opportunistic behaviour
KW  - partial protandry
KW  - population demography
Y1  - 2021
U6  - https://doi.org/10.3390/insects12100896
SN  - 2075-4450
VL  - 12
IS  - 10
PB  - MDPI
CY  - Basel
ER  - 
TY  - JOUR
A1  - Wendt, Martin
A1  - Bouche, Nicolas F.
A1  - Zabl, Johannes
A1  - Schroetter, Ilane
A1  - Muzahid, Sowgat
T1  - MusE GAs FLOw and Wind V. The dust/metallicity-anisotropy of the circum-galactic medium
JF  - Monthly notices of the Royal Astronomical Society
N2  - We investigate whether the dust content of the circum-galactic medium (CGM) depends on the location of the quasar sightline with respect to the galaxy major-axis using 13 galaxy-Mg II absorber pairs (9-81 kpc distance) from the MusE GAs FLOw and Wind (MEGAFLOW) survey at 0.4 < z < 1.4. The dust content of the CGM is obtained from [Zn/Fe] using ultraviolet and visual echelle spectrograph data. When a direct measurement of [Zn/Fe] is unavailable, we estimate the dust depletion from a method that consists in solving for the depletion from multiple singly ionized ions (e.g. Mn II, Cr II, and Zn II) since each ion depletes on dust grains at different rates. We find a positive correlation between the azimuthal angle and [Zn/Fe] with a Pearson's gamma = 0.70 +/- 0.14. The sightlines along the major axis show [Zn/Fe] < 0.5, whereas the [Zn/Fe] is > 0.8 along the minor axis. These results suggest that the CGM along the minor axis is on average more metal enriched (by approximate to 1 dex) than the gas located along the major axis of galaxies provided that dust depletion is a proxy for metallicity. This anisotropic distribution is consistent with recent results on outflow and accretion in hydro-dynamical simulations.
KW  - galaxies: evolution
KW  - galaxies: formation
KW  - intergalactic medium
KW  - quasars:
KW  - absorption lines
Y1  - 2021
U6  - https://doi.org/10.1093/mnras/stab049
SN  - 0035-8711
SN  - 1365-2966
VL  - 502
IS  - 3
SP  - 3733
EP  - 3745
PB  - Oxford Univ. Press
CY  - Oxford
ER  - 
TY  - JOUR
A1  - Bouma, Sietske Jeltje Deirdre
A1  - Richter, Philipp
A1  - Wendt, Martin
T1  - The relation between Ly alpha absorbers and local galaxy filaments
JF  - Astronomy and astrophysics : an international weekly journal
N2  - Context. The intergalactic medium (IGM) is believed to contain the majority of baryons in the universe and to trace the same dark matter structure as galaxies, forming filaments and sheets. Ly alpha absorbers, which sample the neutral component of the IGM, have been extensively studied at low and high redshift, but the exact relation between Ly alpha absorption, galaxies, and the large-scale structure is observationally not well constrained.Aims. In this study, we aim at characterising the relation between Ly alpha absorbers and nearby over-dense cosmological structures (galaxy filaments) at recession velocities Delta v <= 6700 km s(-1) by using archival observational data from various instruments.Methods. We analyse 587 intervening Ly alpha absorbers in the spectra of 302 extragalactic background sources obtained with the Cosmic Origins Spectrograph (COS) installed on the Hubble Space Telescope (HST). We combine the absorption line information with galaxy data of five local galaxy filaments from the V8k catalogue.Results. Along the 91 sightlines that pass close to a filament, we identify 215 (227) Ly alpha absorption systems (components). Among these, 74 Ly alpha systems are aligned in position and velocity with the galaxy filaments, indicating that these absorbers and the galaxies trace the same large-scale structure. The filament-aligned Ly alpha absorbers have a similar to 90% higher rate of incidence (d?/dz=189 for log N(HI) >= 13.2) and a slightly shallower column density distribution function slope (-beta=-1.47) relative to the general Ly alpha population at z=0, reflecting the filaments' matter over-density. The strongest Ly alpha absorbers are preferentially found near galaxies or close to the axis of a filament, although there is substantial scatter in this relation. Our sample of absorbers clusters more strongly around filament axes than a randomly distributed sample would do (as confirmed by a Kolmogorov-Smirnov test), but the clustering signal is less pronounced than for the galaxies in the filaments.
KW  - galaxies: halos
KW  - intergalactic medium
KW  - quasars: absorption lines
KW  - large-scale structure of Universe
KW  - techniques: spectroscopic
KW  - ultraviolet: general
Y1  - 2021
U6  - https://doi.org/10.1051/0004-6361/202039786
SN  - 0004-6361
SN  - 1432-0746
VL  - 647
PB  - EDP Sciences
CY  - Les Ulis
ER  - 
TY  - JOUR
A1  - Guber, Christoph Rudolf
A1  - Richter, Philipp
A1  - Wendt, Martin
T1  - Multiple origins for the DLA at zabs = 0.313 toward PKS 1127–145 indicated by a complex dust depletion pattern of Ca, Ti, and Mn
JF  - Astronomy and astrophysics : an international weekly journal
N2  - Aims:
We aim to investigate the dust depletion properties of optically thick gas in and around galaxies and its origin we study in detail the dust depletion patterns of Ti, Mn, and Ca in the multi-component damped Lyman alpha (DLA) absorber at z(abs) = 0.313 toward the quasar PKS 1127-145. Methods:
We performed a detailed spectral analysis of the absorption profiles of Ca II, Mn II, TIII, and Na I associated with the DLA toward PKS 1127-145, based on optical high-resolution data obtained with the UVES instrument at the Very Large Telescope. We obtained column densities and Doppler-parameters for the ions listed above and determine their gas-phase abundances, from which we conclude on their dust depletion properties. We compared the Ca and Ti depletion properties of this DLA with that of other DLAs. 
Results:
One of the six analyzed absorption components (component 3) shows a striking underabundance of Ti and Mn in the gas-phase, indicating the effect of dust depletion for these elements and a locally enhanced dust-to-gas ratio. In this DLA and in other similar absorbers, the Mn II abundance follows that of Ti II very closely, implying that both ions are equally sensitive to the dust depletion effects. 
Conclusions:
Our analysis indicates that the DLA toward PKS 1127 145 has multiple origins. With its narrow line width and its strong dust depletion, component 3 points toward the presence of a neutral gas disk from a faint LSB galaxy in front of PKS 1127 145, while the other, more diffuse and dust-poor, absorption components possibly are related to tidal gas features from the interaction between the various, optically confirmed galaxy-group members. In general, the Mn/Ca II ratio in sub-DLAs and DLAs possibly serves as an important indicator to discriminate between dust-rich and dust-poor in neutral gas in and around galaxies.
KW  - quasars: absorption lines
KW  - galaxies: abundances
KW  - intergalactic medium
KW  - quasars: individual: PKS1127-145
KW  - dust, extinction
KW  - ISM: kinematics and dynamics
Y1  - 2018
U6  - https://doi.org/10.1051/0004-6361/201730984
SN  - 1432-0746
VL  - 609
PB  - EDP Sciences
CY  - Les Ulis
ER  - 
TY  - JOUR
A1  - Kamann, Sebastian
A1  - Husser, T. -O.
A1  - Dreizler, S.
A1  - Emsellem, E.
A1  - Weilbacher, Peter Michael
A1  - Martens, S.
A1  - Bacon, R.
A1  - den Brok, M.
A1  - Giesers, B.
A1  - Krajnovic, Davor
A1  - Roth, Martin M.
A1  - Wendt, Martin
A1  - Wisotzki, Lutz
T1  - A stellar census in globular clusters with MUSE
BT  - the contribution of rotation to cluster dynamics studied with 200 000 stars
JF  - Monthly notices of the Royal Astronomical Society
N2  - This is the first of a series of papers presenting the results from our survey of 25 Galactic globular clusters with the MUSE integral-field spectrograph. In combination with our dedicated algorithm for source deblending, MUSE provides unique multiplex capabilities in crowded stellar fields and allows us to acquire samples of up to 20 000 stars within the half-light radius of each cluster. The present paper focuses on the analysis of the internal dynamics of 22 out of the 25 clusters, using about 500 000 spectra of 200 000 individual stars. Thanks to the large stellar samples per cluster, we are able to perform a detailed analysis of the central rotation and dispersion fields using both radial profiles and two-dimensional maps. The velocity dispersion profiles we derive show a good general agreement with existing radial velocity studies but typically reach closer to the cluster centres. By comparison with proper motion data, we derive or update the dynamical distance estimates to 14 clusters. Compared to previous dynamical distance estimates for 47 Tuc, our value is in much better agreement with other methods. We further find significant (>3 sigma) rotation in the majority (13/22) of our clusters. Our analysis seems to confirm earlier findings of a link between rotation and the ellipticities of globular clusters. In addition, we find a correlation between the strengths of internal rotation and the relaxation times of the clusters, suggesting that the central rotation fields are relics of the cluster formation that are gradually dissipated via two-body relaxation.
KW  - techniques: imaging spectroscopy
KW  - stars: kinematics and dynamics
KW  - globular clusters: general
Y1  - 2017
U6  - https://doi.org/10.1093/mnras/stx2719
SN  - 0035-8711
SN  - 1365-2966
VL  - 473
IS  - 4
SP  - 5591
EP  - 5616
PB  - Oxford Univ. Press
CY  - Oxford
ER  - 
TY  - JOUR
A1  - Weilbacher, Peter Michael
A1  - Monreal-Ibero, Ana
A1  - Verhamme, Anne
A1  - Sandin, Christer
A1  - Steinmetz, Matthias
A1  - Kollatschny, Wolfram
A1  - Krajnovic, Davor
A1  - Kamann, Sebastian
A1  - Roth, Martin M.
A1  - Erroz-Ferrer, Santiago
A1  - Marino, Raffaella Anna
A1  - Maseda, Michael V.
A1  - Wendt, Martin
A1  - Bacon, Roland
A1  - Dreizler, Stefan
A1  - Richard, Johan
A1  - Wisotzki, Lutz
T1  - Lyman-continuum leakage as dominant source of diffuse ionized gas in the Antennae galaxy
JF  - Astronomy and astrophysics : an international weekly journal
N2  - The Antennae galaxy (NGC 4038/39) is the closest major interacting galaxy system and is therefore often studied as a merger prototype. We present the first comprehensive integral field spectroscopic dataset of this system, observed with the MUSE instrument at the ESO VLT. We cover the two regions in this system which exhibit recent star formation: the central galaxy interaction and a region near the tip of the southern tidal tail. In these fields, we detect H II regions and diffuse ionized gas to unprecedented depth. About 15% of the ionized gas was undetected by previous observing campaigns. This newly detected faint ionized gas is visible everywhere around the central merger, and shows filamentary structure. We estimate diffuse gas fractions of about 60% in the central field and 10% in the southern region. We are able to show that the southern region contains a significantly different population of H II regions, showing fainter luminosities. By comparing H II region luminosities with the HST catalog of young star clusters in the central field, we estimate that there is enough Lyman-continuum leakage in the merger to explain the amount of diffuse ionized gas that we detect. We compare the Lyman-continuum escape fraction of each H II region against emission line ratios that are sensitive to the ionization parameter. While we find no systematic trend between these properties, the most extreme line ratios seem to be strong indicators of density bounded ionization. Extrapolating the Lyman-continuum escape fractions to the southern region, we conclude that simply from the comparison of the young stellar populations to the ionized gas there is no need to invoke other ionization mechanisms than Lyman-continuum leaking H II regions for the diffuse ionized gas in the Antennae.
KW  - galaxies: interactions
KW  - galaxies: individual: NGC 4038, NGC 4039
KW  - galaxies: ISM
KW  - ISM: structure
KW  - H II regions
Y1  - 2018
U6  - https://doi.org/10.1051/0004-6361/201731669
SN  - 1432-0746
VL  - 611
PB  - EDP Sciences
CY  - Les Ulis
ER  - 
TY  - JOUR
A1  - Marino, Raffaella Anna
A1  - Cantalupo, Sebastiano
A1  - Lilly, Simon J.
A1  - Gallego, Sofia G.
A1  - Straka, Lorrie A.
A1  - Borisova, Elena
A1  - Pezzulli, Gabriele
A1  - Bacon, Roland
A1  - Brinchmann, Jarle
A1  - Carollo, C. Marcella
A1  - Caruana, Joseph
A1  - Conseil, Simon
A1  - Contini, Thierry
A1  - Diener, Catrina
A1  - Finley, Hayley
A1  - Inami, Hanae
A1  - Leclercq, Floriane
A1  - Muzahid, Sowgat
A1  - Richard, Johan
A1  - Schaye, Joop
A1  - Wendt, Martin
A1  - Wisotzki, Lutz
T1  - Dark Galaxy Candidates at Redshift similar to 3.5 Detected with MUSE
JF  - The astrophysical journal : an international review of spectroscopy and astronomical physics
N2  - Recent theoretical models suggest that the early phase of galaxy formation could involve an epoch when galaxies are gas rich but inefficient at forming stars: a "dark galaxy" phase. Here, we report the results of our Multi-Unit Spectroscopic Explorer (MUSE) survey for dark galaxies fluorescently illuminated by quasars at z > 3. Compared to previous studies which are based on deep narrowband (NB) imaging, our integral field survey provides a nearly uniform sensitivity coverage over a large volume in redshift space around the quasars as well as full spectral information at each location. Thanks to these unique features, we are able to build control samples at large redshift distances from the quasars using the same data taken under the same conditions. By comparing the rest-frame equivalent width (EW0) distributions of the Ly alpha sources detected in proximity to the quasars and in control samples, we detect a clear correlation between the locations of high-EW0 objects and the quasars. This correlation is not seen in other properties, such as Ly alpha luminosities or volume overdensities, suggesting the possible fluorescent nature of at least some of these objects. Among these, we find six sources without continuum counterparts and EW0 limits larger than 240 angstrom that are the best candidates for dark galaxies in our survey at z > 3.5. The volume densities and properties, including inferred gas masses and star formation efficiencies, of these dark galaxy candidates are similar to those of previously detected candidates at z approximate to 2.4 in NB surveys. Moreover, if the most distant of these are fluorescently illuminated by the quasar, our results also provide a lower limit of t - 60 Myr on the quasar lifetime.
KW  - galaxies: formation
KW  - galaxies: high-redshift
KW  - galaxies: star formation
KW  - intergalactic medium
KW  - quasars: emission lines
KW  - quasars: general
Y1  - 2018
U6  - https://doi.org/10.3847/1538-4357/aab6aa
SN  - 0004-637X
SN  - 1538-4357
VL  - 859
IS  - 1
PB  - IOP Publ. Ltd.
CY  - Bristol
ER  - 
TY  - JOUR
A1  - Monreal-Ibero, Ana
A1  - Weilbacher, Peter Michael
A1  - Wendt, Martin
T1  - Diffuse interstellar bands lambda 5780 and lambda 5797 in the Antennae Galaxy as seen by MUSE
JF  - Astronomy and astrophysics : an international weekly journal
N2  - Context. Diffuse interstellar bands (DIBs) are faint spectral absorption features of unknown origin. Research on DIBs beyond the Local Group is very limited and will surely blossom in the era of the Extremely Large Telescopes. However, we can already start paving the way. One possibility that needs to be explored is the use of high-sensitivity integral field spectrographs. Aims. Our goals are twofold. First, we aim to derive reliable mapping of at least one DIB in a galaxy outside the Local Group. Second, we want to explore the relation between DIBs and other properties of the interstellar medium (ISM) in the galaxy. Methods. We use Multi Unit Spectroscopic Explorer (MUSE) data for the Antennae Galaxy, the closest major galaxy merger. High signal-to-noise spectra were created by co-adding the signal of many spatial elements with the Voronoi binning technique. The emission of the underlying stellar population was modelled and substracted with the STARLIGHT spectral synthesis code. Flux and equivalent width of the features of interest were measured by means of fitting to Gaussian functions. Conclusions. The results illustrate the enormous potential of integral field spectrographs for extragalactic DIB research.
KW  - dust, extinction
KW  - ISM: lines and bands
KW  - galaxies: ISM
KW  - galaxies: individual: Antennae Galaxy
KW  - galaxies: interactions
KW  - ISM: structure
Y1  - 2018
U6  - https://doi.org/10.1051/0004-6361/201732178
SN  - 1432-0746
VL  - 615
PB  - EDP Sciences
CY  - Les Ulis
ER  - 
TY  - JOUR
A1  - Wisotzki, Lutz
A1  - Bacon, R.
A1  - Brinchmann, J.
A1  - Cantalupo, S.
A1  - Richter, Philipp
A1  - Schaye, J.
A1  - Schmidt, Kasper Borello
A1  - Urrutia, Tanya
A1  - Weilbacher, Peter Michael
A1  - Akhlaghi, M.
A1  - Bouche, N.
A1  - Contini, T.
A1  - Guiderdoni, B.
A1  - Herenz, E. C.
A1  - Inami, H.
A1  - Kerutt, Josephine Victoria
A1  - Leclercq, F.
A1  - Marino, R. A.
A1  - Maseda, M.
A1  - Monreal-Ibero, A.
A1  - Nanayakkara, T.
A1  - Richard, J.
A1  - Saust, R.
A1  - Steinmetz, Matthias
A1  - Wendt, Martin
T1  - Nearly all the sky is covered by Lyman-alpha emission around high-redshift galaxies
JF  - Nature : the international weekly journal of science
N2  - Galaxies are surrounded by large reservoirs of gas, mostly hydrogen, that are fed by inflows from the intergalactic medium and by outflows from galactic winds. Absorption-line measurements along the lines of sight to bright and rare background quasars indicate that this circumgalactic medium extends far beyond the starlight seen in galaxies, but very little is known about its spatial distribution. The Lyman-alpha transition of atomic hydrogen at a wavelength of 121.6 nanometres is an important tracer of warm (about 104 kelvin) gas in and around galaxies, especially at cosmological redshifts greater than about 1.6 at which the spectral line becomes observable from the ground. Tracing cosmic hydrogen through its Lyman-a emission has been a long-standing goal of observational astrophysics(1-3), but the extremely low surface brightness of the spatially extended emission is a formidable obstacle. A new window into circumgalactic environments was recently opened by the discovery of ubiquitous extended Lyman-alpha emission from hydrogen around high-redshift galaxies(4,5). Such measurements were previously limited to especially favourable systems(6-8) or to the use of massive statistical averaging(9,10) because of the faintness of this emission. Here we report observations of low-surface-brightness Lyman-alpha emission surrounding faint galaxies at redshifts between 3 and 6. We find that the projected sky coverage approaches 100 per cent. The corresponding rate of incidence (the mean number of Lyman-alpha emitters penetrated by any arbitrary line of sight) is well above unity and similar to the incidence rate of high-column-density absorbers frequently detected in the spectra of distant quasars(11-14). This similarity suggests that most circumgalactic atomic hydrogen at these redshifts has now been detected in emission.
Y1  - 2018
U6  - https://doi.org/10.1038/s41586-018-0564-6
SN  - 0028-0836
SN  - 1476-4687
VL  - 562
IS  - 7726
SP  - 229
EP  - 232
PB  - Nature Publ. Group
CY  - London
ER  - 
TY  - JOUR
A1  - Paalvast, M.
A1  - Verhamme, A.
A1  - Straka, L. A.
A1  - Brinchmann, J.
A1  - Herenz, Edmund Christian
A1  - Carton, D.
A1  - Gunawardhana, M. L. P.
A1  - Boogaard, L. A.
A1  - Cantalupo, S.
A1  - Contini, T.
A1  - Epinat, Benoit
A1  - Inami, H.
A1  - Marino, R. A.
A1  - Maseda, M. V.
A1  - Michel-Dansac, L.
A1  - Muzahid, S.
A1  - Nanayakkara, T.
A1  - Pezzulli, Gabriele
A1  - Richard, J.
A1  - Schaye, Joop
A1  - Segers, M. C.
A1  - Urrutia, Tanya
A1  - Wendt, Martin
A1  - Wisotzki, Lutz
T1  - Properties and redshift evolution of star-forming galaxies with high [0 III]/[O II] ratios with MUSE at 0.28 < z < 0.85
JF  - Astronomy and astrophysics : an international weekly journal
N2  - We present a study of the [O III]/[O II] ratios of star-forming galaxies drawn from Multi-Unit Spectroscopic Explorer (MUSE) data spanning a redshift range 0.28 < z < 0.85. Recently discovered Lyman continuum (LyC) emitters have extremely high oxygen line ratios: [O III]lambda 5007/[O II]lambda lambda 3726, 3729 > 4. Here we aim to understand the properties and the occurrences of galaxies with such high line ratios. Combining data from several MUSE Guaranteed Time Observing (GTO) programmes, we select a population of star-forming galaxies with bright emission lines, from which we draw 406 galaxies for our analysis based on their position in the z-dependent star formation rate (SFR) stellar mass (M*) plane. Out of this sample 15 are identified as extreme oxygen emitters based on their [O III]/[O II] ratios (3.7%) and 104 galaxies have [O III]/[O II] > 1 (26%). Our analysis shows no significant correlation between M*, SFR, and the distance from the SFR M, relation with [O III]/[O II]. We find a decrease in the fraction of galaxies with [O III]/[O II] > 1 with increasing M*, however, this is most likely a result of the relationship between [O III]/[O II] and metallicity, rather than between [O III]/[O II] and M. We draw a comparison sample of local analogues with < z > 0.03 from the Sloan Digital Sky Survey, and find similar incidence rates for this sample. In order to investigate the evolution in the fraction of high [O III]/[O II] emitters with redshift, we bin the sample into three redshift subsamples of equal number, but find no evidence for a dependence on redshift. Furthermore, we compare the observed line ratios with those predicted by nebular models with no LyC escape and find that most of the extreme oxygen emitters can be reproduced by low metallicity models. The remaining galaxies are likely LyC emitter candidates.
KW  - galaxies: evolution
KW  - galaxies: ISM
KW  - galaxies: abundances
KW  - ISM: structure
KW  - ISM: kinematics and dynamics
KW  - dark ages, reionization, first stars
Y1  - 2018
U6  - https://doi.org/10.1051/0004-6361/201832866
SN  - 0004-6361
SN  - 1432-0746
VL  - 618
PB  - EDP Sciences
CY  - Les Ulis
ER  -