Candidate Population III stellar complex at z = 6.629 in the MUSE Deep Lensed Field
Date Issued
2020
Author(s)
•
•
Caminha, G. B.
•
•
•
•
GRILLO, CLAUDIO
•
Dijkstra, M.
•
Gronke, M.
•
Sani, E.
•
•
•
•
•
•
•
•
Treu, Tommaso
•
Caputi, K.
•
•
•
•
Balestra, Italo
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 Šif 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.
Volume
494
Issue
1
Start page
L81
Issn Identifier
1745-3925
Ads BibCode
2020MNRAS.494L..81V
Rights
open.access
File(s)![Thumbnail Image]()
Loading...
Name
mnrasl_494_1_l81.pdf
Description
PDF editoriale
Size
1.97 MB
Format
Adobe PDF
Checksum (MD5)
5e8939875c44a443b41a9011bb4b6a90