A Virgo Environmental Survey Tracing Ionised Gas Emission (VESTIGE) IV
A&A 620, A164 (2018) Astronomy https://doi.org/10.1051/0004-6361/201833914 & c ESO 2018 Astrophysics A Virgo Environmental Survey Tracing Ionised Gas Emission (VESTIGE) IV. A tail of ionised gas in the merger remnant NGC 4424 A. Boselli1,?, M. Fossati2,3, G. Consolandi4, P. Amram1, C. Ge5, M. Sun5, J. P. Anderson6, S. Boissier1, M. Boquien7, V. Buat1, D. Burgarella1, L. Cortese8,9, P. Côté10, J. C. Cuillandre11, P. Durrell12, B. Epinat1, L. Ferrarese10, M. Fumagalli3, L. Galbany13, G. Gavazzi4, J. A. Gómez-López1, S. Gwyn10, G. Hensler14, H. Kuncarayakti15,16, M. Marcelin1, C. Mendes de Oliveira17, B. C. Quint18, J. Roediger10, Y. Roehlly19, S. F. Sanchez20, R. Sanchez-Janssen21, E. Toloba22,23, G. Trinchieri24, and B. Vollmer25 (Affiliations can be found after the references) Received 20 July 2018 / Accepted 22 October 2018 ABSTRACT We observed the late-type peculiar galaxy NGC 4424 during the Virgo Environmental Survey Tracing Galaxy Evolution (VESTIGE), a blind narrow-band Hα+[NII] imaging survey of the Virgo cluster carried out with MegaCam at the Canada-French-Hawaii Telescope (CFHT). The presence of a ∼110 kpc (in projected distance) HI tail in the southern direction indicates that this galaxy is undergoing a ram pressure stripping event. The deep narrow-band image revealed a low surface brightness (Σ(Hα) ' 4 × 10−18 erg s−1 cm−2 arcsec−2) ionised gas tail ∼10 kpc in length extending from the centre of the galaxy to the north-west, thus in the direction opposite to the HI tail. Chandra and XMM X-rays data do not show a compact source in the nucleus or an extended tail of hot gas, while IFU spectroscopy (MUSE) indicates that the gas is photo-ionised in the inner regions and shock-ionised in the outer parts.
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