Data di Pubblicazione:
2020
Citazione:
Candidate Population III stellar complex at z = 6.629 in the MUSE Deep Lensed Field / E. Vanzella, M. Meneghetti, G. B Caminha, M. Castellano, F. Calura, P. Rosati, C. Grillo, M. Dijkstra, M. Gronke, E. Sani, A. Mercurio, P. Tozzi, M. Nonino, S. Cristiani, M. Mignoli, L. Pentericci, R. Gilli, T. Treu, K. Caputi, G. Cupani, A. Fontana, A. Grazian, I. Balestra. - In: MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY. LETTERS. - ISSN 1745-3925. - 494:1(2020 May 01), pp. L81-L85. [10.1093/mnrasl/slaa041]
Abstract:
We discovered a strongly lensed (μ ≳ 40) Ly α emission at z = 6.629 (S/N ≃ 18) in the MUSE Deep Lensed Field (MDLF) targeting the Hubble Frontier Field (HFF) galaxy cluster MACS J0416. Dedicated lensing simulations imply that the Ly α emitting region necessarily crosses the caustic. The arc-like shape of the Ly α extends 3 arcsec on the observed plane and is the result of two merged multiple images, each one with a de-lensed Ly α luminosity L ≲ 2.8 × 1040 erg s−1 arising from a confined region (≲150 pc effective radius). A spatially unresolved Hubble Space Telescope (HST) counterpart is barely detected at S/N ≃ 2 after stacking the near-infrared bands, corresponding to an observed (intrinsic) magnitude m1500 ≳ 30.8 (≳35.0). The inferred rest-frame Ly α equivalent width is EW0 > 1120 Å if the IGM transmission is TIGM < 0.5. The low luminosities and the extremely large Ly α EW0 match the case of a Population III (Pop III) star complex made of several dozens stars (∼104 M☉) that irradiate an H II region crossing the caustic. While the Ly α and stellar continuum are among the faintest ever observed at this redshift, the continuum and the Ly α emissions could be affected by differential magnification, possibly biasing the EW0 estimate. The aforementioned tentative HST detection tends to favour a large EW0, making such a faint Pop III candidate a key target for the James Webb Space Telescope and Extremely Large Telescopes.
Tipologia IRIS:
01 - Articolo su periodico
Keywords:
Galaxies: formation; Galaxies: starburst; Gravitational lensing: strong;
Elenco autori:
E. Vanzella, M. Meneghetti, G. B Caminha, M. Castellano, F. Calura, P. Rosati, C. Grillo, M. Dijkstra, M. Gronke, E. Sani, A. Mercurio, P. Tozzi, M. Nonino, S. Cristiani, M. Mignoli, L. Pentericci, R. Gilli, T. Treu, K. Caputi, G. Cupani, A. Fontana, A. Grazian, I. Balestra
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