Bibcode
Richard, J.; Pelló, R.; Marques-Chaves, R.; Kneib, J.-P.; Boone, F.; Atek, H.; Laporte, N.; Streblyanska, A.; Clement, B.; Pérez-Fournon, I.; Schaerer, D.; Martínez-Navajas, P.; Egami, E.
Referencia bibliográfica
Astronomy and Astrophysics, Volume 562, id.L8, 4 pp.
Fecha de publicación:
2
2014
Revista
Número de citas
58
Número de citas referidas
49
Descripción
Aims: We present in this letter the first analysis of a z ~ 8
galaxy candidate found in the Hubble and Spitzer imaging data of Abell
2744 as part of the Hubble Frontier Fields legacy program.
Methods: We applied the most commonly used methods to select
exceptionally high-redshift galaxies by combining non-detection and
color criteria using seven HST bands. We used GALFIT on IRAC images to
fit and subtract contamination of bright nearby sources.The physical
properties were inferred from spectral energy distribution-fitting using
templates with and without nebular emission. Results: This letter
is focused on the brightest candidate we found (mF160W =
26.2) over the 4.9 arcmin2 field of view covered by the WFC3.
It is not detected in the ACS bands and at 3.6 μm, while it is
clearly detected at 4.5 μm with rather similar depths. This break in
the IRAC data might be explained by strong [OIII]+Hβ lines at z ~ 8
that contribute to the 4.5 μm photometry. The best photo-z is found
at z ~ 8.0+0.2-0.5, although solutions at
low-redshift (z ~ 1.9) cannot be completely excluded , but they are
strongly disfavored by the SED-fitting. The amplification factor is
relatively small at μ = 1.49 ± 0.02. The star formation rate
in this object ranges from 8 to 60 M⊙ yr-1,
the stellar mass is on the order of M⋆ = (2.5-10)
× 109 M⊙, and the size is r ≈ 0.35
± 0.15 kpc. Conclusions: This object is one of the first z
~ 8 Lyman break galaxy candidates showing a clear break between 3.6
μm and 4.5 μm, which is consistent with the IRAC properties of the
first spectroscopically confirmed galaxy at a similar redshift. Due to
its brightness, the redshift of this object could potentially be
confirmed by near-infrared spectroscopy with current 8-10 m telescopes.
The nature of this candidate will be revealed in the coming months with
the arrival of new ACS and Spitzer data, increasing the depth at optical
and near-infrared wavelengths.
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Ismael
Pérez Fournon