Browsing by Author "Kusakabe, H."

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    A ∼15 kpc outflow cone piercing through the halo of the blue compact metal-poor galaxy SBS 0335-052E
    (2023) Herenz, E. C.; Inoue, J.; Salas, H.; Koenigs, B.; Moya-Sierralta, C.; Cannon, J. M.; Hayes, M.; Papaderos, P.; Oestlin, G.; Bik, A.; Le Reste, A.; Kusakabe, H.; Monreal-Ibero, A.; Puschnig, J.
    Context. Outflows from low-mass star-forming galaxies are a fundamental ingredient for models of galaxy evolution and cosmology. Despite seemingly favourable conditions for outflow formation in compact starbursting galaxies, convincing observational evidence for kiloparsec-scale outflows in such systems is scarce. Aims. The onset of kiloparsec-scale ionised filaments in the halo of the metal-poor compact dwarf SBS 0335-052E was previously not linked to an outflow. In this paper we investigate whether these filaments provide evidence for an outflow. Methods. We obtained new VLT/MUSE WFM and deep NRAO/VLA B-configuration 21 cm data of the galaxy. The MUSE data provide morphology, kinematics, and emission line ratios of H beta/H alpha and [O III]lambda 5007/H alpha of the low surface-brightness filaments, while the VLA data deliver morphology and kinematics of the neutral gas in and around the system. Both datasets are used in concert for comparisons between the ionised and the neutral phase. Results. We report the prolongation of a lacy filamentary ionised structure up to a projected distance of 16 kpc at SBH alpha = 1.5 x 10(-18) erg s cm(-2) arcsec(-2). The filaments exhibit unusual low H alpha/H beta approximate to 2.4 and low [O III]/H alpha similar to 0.4 - 0.6 typical of diffuse ionised gas. They are spectrally narrow (similar to 20 km s(-1)) and exhibit no velocity sub-structure. The filaments extend outwards from the elongated H I halo. On small scales, the N-HI peak is offset from the main star-forming sites. The morphology and kinematics of H I and H II reveal how star-formation-driven feedback interacts differently with the ionised and the neutral phase. Conclusions. We reason that the filaments are a large-scale manifestation of star-formation- driven feedback, namely limb-brightened edges of a giant outflow cone that protrudes through the halo of this gas-rich system. A simple toy model of such a conical structure is found to be commensurable with the observations.
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    MUSE observations towards the lensing cluster A2744: Intersection between the LBG and LAE populations at z ∼ 3-7
    (2020) de La Vieuville, G.; Pello, R.; Richard, J.; Mahler, G.; Leveque, L.; Bauer, F. E.; Lagattuta, D. J.; Blaizot, J.; Contini, T.; Guaita, L.; Kusakabe, H.; Laporte, N.; Martinez, J.; Maseda, M., V; Schaerer, D.; Schmidt, K. B.; Verhamme, A.
    We present a study of the intersection between the populations of star forming galaxies selected as either Lyman break galaxies (LBGs) or Lyman-alpha emitters (LAEs) in the redshift range 2.9-6.7 and within the same volume of universe sampled by the Multi-Unit Spectroscopic Explorer (MUSE) behind the Hubble Frontier Fields lensing cluster A2744. We define three samples of star-forming galaxies: LBG galaxies with an LAE counterpart (92 galaxies), LBG galaxies without an LAE counterpart (408 galaxies), and LAE galaxies without an LBG counterpart (46 galaxies). All these galaxies are intrinsically faint because of the lensing nature of the sample (M-1500 >=-20.5). The fraction of LAEs among all selected star-forming galaxies increases with redshift up to z similar to 6 and decreases for higher redshifts, in agreement with previous findings. The evolution of LAE/LBG populations with UV magnitude and Ly alpha luminosity shows that the LAE selection is able to identify intrinsically UV faint galaxies with M-1500 >=-15 that are typically missed in the deepest lensing photometric surveys. The LBG population seems to fairly represent the total population of star-forming galaxies down to M-1500 similar to-15. Galaxies with M-1500<-17 tend to have SFRLy alpha-17, including galaxies only detected by their Ly alpha emission, with a large scatter. These trends, previously observed in other samples of star-forming galaxies at high-z, are seen here for very faint M-1500 similar to-15 galaxies; that is, much fainter than in previous studies. The present results show no clear evidence for an intrinsic difference between the properties of the two populations selected as LBG and/or LAE. The observed trends could be explained by a combination of several phenomena, like the existence of different star-formation regimes, the dust content, the relative distribution and morphology of dust and stars, or the stellar populations.
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    The Lensed Lyman-Alpha MUSE Arcs Sample (LLAMAS) I. Characterisation of extended Lyman-alpha halos and spatial offsets
    (2022) Claeyssens, A.; Richard, J.; Blaizot, J.; Garel, T.; Kusakabe, H.; Bacon, R.; Bauer, F. E.; Guaita, L.; Jeanneau, A.; Lagattuta, D.; Leclercq, F.; Maseda, M.; Matthee, J.; Nanayakkara, T.; Pello, R.; Thai, T. T.; Tuan-Anh, P.; Verhamme, A.; Vitte, E.; Wisotzki, L.
    Aims. We present the Lensed Lyman-Alpha MUSE Arcs Sample (LLAMAS) selected from MUSE and HST observations of 17 lensing clusters. The sample consists of 603 continuum-faint (-23 < M-UV < -14) lensed Lyman-alpha emitters (producing 959 images) with secure spectroscopic redshifts between 2.9 and 6.7. Combining the power of cluster magnification with 3D spectroscopic observations, we were able to reveal the resolved morphological properties of 268 Lyman-alpha emitters.