Reaching for the stars – JWST/NIRSpec spectroscopy of a lensed star candidate at z = 4.76

We present JWST/NIRSpec observations of a highly magnified star candidate at a photometric redshift of zphot 4.8, previously detected in JWST/NIRCam imaging of the strong lensing (SL) cluster MACS J0647+7015 (z = 0.591). The spectroscopic observation allows us to precisely measure the redshift of th...

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Detalhes bibliográficos
Autores: Furtak, Lukas J., Meena, Ashish Kumar, Zackrisson, Erik, Zitrin, Adi, Brammer, Gabriel, Coe, Dan, Diego, José María, Eldridge, Jan J., Jiménez-Teja, Y., Kokorev, Vasily, Ricotti, Massimo, Welch, Brian, Windhorst, Rogier A., Abdurro'uf, Andrade-Santos, Felipe, Bhatawdekar, Rachana, Bradley, Larry, Broadhurst, Tom, Chen, Wenlei, Conselice, Christopher J., Dayal, Pratika, Frye, Brenda, Fujimoto, Seiji, Hsiao, Tiger Yu-Yang, Kelly, Patrick L., Mahler, Guillaume, Mandelker, Nir, Norman, Colin, Oguri, Masamune, Pirzkal, Nor, Postman, Marc, Ravindranath, Swara, Vanzella, Eros, Wilkins, Stephen M.
Tipo de documento: artigo
Estado:Versão publicada
Data de publicação:2024
País:España
Recursos:Consejo Superior de Investigaciones Científicas (CSIC)
Repositório:DIGITAL.CSIC. Repositorio Institucional del CSIC
OAI Identifier:oai:digital.csic.es:10261/358435
Acesso em linha:http://hdl.handle.net/10261/358435
Access Level:Acceso aberto
Palavra-chave:Gravitational lensing: micro
Gravitational lensing: strong
Stars: individual: MACS0647-star-1
Stars: massive
Galaxies: high-redshift
Galaxies: star clusters: general
Descrição
Resumo:We present JWST/NIRSpec observations of a highly magnified star candidate at a photometric redshift of zphot 4.8, previously detected in JWST/NIRCam imaging of the strong lensing (SL) cluster MACS J0647+7015 (z = 0.591). The spectroscopic observation allows us to precisely measure the redshift of the host arc at zspec = 4.758 ± 0.004, and the star’s spectrum displays clear Lyman- and Balmer-breaks commensurate with this redshift. A fit to the spectrum suggests a B-type super-giant star of surface temperature Teff,B 15 000 K with either a redder F-type companion (Teff,F 6 250 K) or significant dust attenuation (AV 0.82) along the line of sight. We also investigate the possibility that this object is a magnified young globular cluster rather than a single star. We show that the spectrum is in principle consistent with a star cluster, which could also accommodate the lack of flux variability between the two epochs. However, the lack of a counter image and the strong upper limit on the size of the object from lensing symmetry, r 0.5 pc, could indicate that this scenario is somewhat less likely – albeit not completely ruled out by the current data. The presented spectrum seen at a time when the Universe was only ∼1.2 Gyr old showcases the ability of JWST to study early stars through extreme lensing.

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