2018MNRAS.476..804D -
Mon. Not. R. Astron. Soc., 476, 804-813 (2018/May-1)
Kinematics of the SN Refsdal host revealed by MUSE: a regularly rotating spiral galaxy at z ≃ 1.5.
DI TEODORO E.M., GRILLO C., FRATERNALI F., GOBAT R., KARMAN W., MERCURIO A., ROSATI P., BALESTRA I., CAMINHA G.B., CAPUTI K.I., LOMBARDI M., SUYU S.H., TREU T. and VANZELLA E.
Abstract (from CDS):
We use Multi Unit Spectroscopic Explorer (MUSE) observations of the galaxy cluster MACS J1149.5+2223 to explore the kinematics of the grand-design spiral galaxy (Sp1149) hosting the supernova 'Refsdal'. Sp1149 lies at z ≃ 1.49, has a stellar mass M* ≃ 5 x 109 M☉, has a star formation rate (SFR) ≃1-6 M☉ yr–1, and represents a likely progenitor of a Milky Way-like galaxy. All the four multiple images of Sp1149 in our data show strong [O II]-line emissions pointing to a clear rotation pattern. We take advantage of the gravitational lensing magnification effect (≃4x) on the [O II] emission of the least distorted image to fit three-dimensional kinematic models to the MUSE data cube and derive the rotation curve and the velocity dispersion profile of Sp1149. We find that the rotation curve steeply rises, peaks at R ≃ 1 kpc, and then (initially) declines and flattens to an average Vflat= 128+29–19 km s–1. The shape of the rotation curve is well determined, but the actual value of Vflat is quite uncertain because of the nearly face-on configuration of the galaxy. The intrinsic velocity dispersion due to gas turbulence is almost constant across the entire disc with an average of 27 ± 5 km s–1. This value is consistent with z = 0 measurements in the ionized gas component and a factor of 2-4 lower than other estimates in different galaxies at similar redshifts. The average stellar-to-total mass fraction is of the order of one-fifth. Our kinematic analysis returns the picture of a regular star-forming, mildly turbulent, rotation-dominated (V/σ ≃ 5) spiral galaxy in a 4-Gyr-old Universe.
Abstract Copyright:
© 2018 The Author(s) Published by Oxford University Press on behalf of the Royal Astronomical Society
Journal keyword(s):
gravitational lensing: strong - galaxies: clusters: individual: MACS J1149.5+2223298 - galaxies: high-redshift - galaxies: kinematics and dynamics
Simbad objects:
6
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