Mon. Not. R. Astron. Soc., 483, 3618-3635 (2019/March-1)
Massive star cluster formation under the microscope at z = 6.
VANZELLA E., CALURA F., MENEGHETTI M., CASTELLANO M., CAMINHA G.B., MERCURIO A., CUPANI G., ROSATI P., GRILLO C., GILLI R., MIGNOLI M., FIORENTINO G., ARCIDIACONO C., LOMBINI M. and CORTECCHIA F.
Abstract (from CDS):
We report on a superdense star-forming region with an effective radius (Re) smaller than 13 pc identified at z = 6.143 and showing a star formation rate density ΣSFR ∼ 1000 M☉ yr–1 kpc–2 (or conservatively >300 M☉ yr–1 kpc–2). Such a dense region is detected with S/N >= 40 hosted by a dwarf extending over 440 pc, dubbed D1. D1 is magnified by a factor 17.4(±5.0) behind the Hubble Frontier Field galaxy cluster MACS J0416 and elongated tangentially by a factor 13.2 ± 4.0 (including the systematic errors). The lens model accurately reproduces the positions of the confirmed multiple images with a rms of 0.35 arcsec. D1 is part of an interacting star-forming complex extending over 800 pc. The SED-fitting, the very blue ultraviolet slope (β ≃ -2.5, Fλ ∼ λβ), and the prominent Lyα emission of the stellar complex imply that very young (<10-100 Myr), moderately dust-attenuated (E(B - V) < 0.15) stellar populations are present and organized in dense subcomponents. We argue that D1 (with a stellar mass of 2 x 107 M☉) might contain a young massive star cluster of M <= 106 M☉ and MUV ≃ -15.6 (or mUV = 31.1), confined within a region of 13 pc, and not dissimilar from some local super star clusters (SSCs). The ultraviolet appearance of D1 is also consistent with a simulated local dwarf hosting an SSC placed at z = 6 and lensed back to the observer. This compact system fits into some popular globular cluster formation scenarios. We show that future high spatial resolution imaging (e.g. E-ELT/MAORY-MICADO and VLT/MAVIS) will allow us to spatially resolve light profiles of 2-8 pc.
© 2018 The Author(s) Published by Oxford University Press on behalf of the Royal Astronomical Society
gravitational lensing: strong - galaxies: formation - galaxies: starburst
D1 = [MAC2016] M0416cl 2179 ; T1 = [MAC2016] M0416cl 2169 ; UT1 = [MAC2016] M0416cl 22692.
View the reference in ADS
To bookmark this query, right click on this link: simbad:2019MNRAS.483.3618V and select 'bookmark this link' or equivalent in the popup menu