Delving deep: A population of extremely dusty dwarfs observed by JWST

Bisigello, Laura; Gandolfi, G.; Grazian, A.; Rodighiero, G.; Costantin, Luca; Cooray, A. R.; Feltre, Anna

doi:10.1051/0004-6361/202346219

Cited by 12 publications

(8 citation statements)

References 73 publications

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“…Figure compares the magnitudes and colors of our detected point sources. Most sources have 0 < [F356W]-[F444W] < 1 Vega mag (or 0.7 ± 0.5 AB mag), consistent with typical galaxy colors at this sensitivity level (Figures 30 and 31 in Ashby et al 2013;Bisigello et al 2023). The newly identified source S7, however, only has an upper limit on its [F356W]-[F444W] color.…”

Section: Sources In the Vicinity Of Fomalhautsupporting

confidence: 65%

Searching for Planets Orbiting Fomalhaut with JWST/NIRCam

Ygouf,

Beichman,

Llop-Sayson

et al. 2023

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We report observations with the JWST/NIRCam coronagraph of the Fomalhaut (α PsA) system. This nearby A star hosts a complex debris disk system discovered by the IRAS satellite. Observations in F444W and F356W filters using the round 430R mask achieve a contrast ratio of ∼4 × 10−7 at 1″ and ∼4 × 10−8 outside of 3″. These observations reach a sensitivity limit of <1 M Jup across most of the disk region. Consistent with the hypothesis that Fomalhaut b is not a massive planet but is a dust cloud from a planetesimal collision, we do not detect it in either F356W or F444W (the latter band where a Jovian-sized planet should be bright). We have reliably detected 10 sources in and around Fomalhaut and its debris disk, all but one of which are coincident with Keck or Hubble Space Telescope sources seen in earlier coronagraphic imaging; we show them to be background objects, including the “Great Dust Cloud” identified in Mid-Infrared Instrument (MIRI) data. However, one of the objects, located at the edge of the inner dust disk seen in the MIRI images, has no obvious counterpart in imaging at earlier epochs and has a relatively red [F356W]–[F444W] > 0.7 mag (Vega) color. Whether this object is a background galaxy, brown dwarf, or a Jovian-mass planet in the Fomalhaut system will be determined by an approved Cycle 2 follow-up program. Finally, we set upper limits to any scattered light from the outer ring, placing a weak limit on the dust albedo at F356W and F444W.

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Section: Sources In the Vicinity Of Fomalhautsupporting

confidence: 65%

Searching for Planets Orbiting Fomalhaut with JWST/NIRCam

Ygouf,

Beichman,

Llop-Sayson

et al. 2023

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“…They are relatively blue in F115W − F200W while extending to the reddest F200W − F356W colors, even when removing the contribution of the strong emission line to the F356W photometry. This is unlike the dominant population of bright galaxies with red F200W − F356W colors that are dusty star-forming galaxies at z ≈ 1-4 (e.g., Bisigello et al 2023;Glazebrook et al 2023) emitters (e.g., Matthee et al 2023;Rinaldi et al 2023) have relatively similar colors as BL Hα emitters, typically being blue in F115W − F200W and red in F200W − F356W. However, they are not as red in the latter color as their redness is caused by line emission on top of a relatively flat continuum.…”

Section: Jwst Colorsmentioning

confidence: 89%

Little Red Dots: An Abundant Population of Faint Active Galactic Nuclei at z ∼ 5 Revealed by the EIGER and FRESCO JWST Surveys

Matthee,

Naidu,

Brammer

et al. 2024

ApJ

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Characterizing the prevalence and properties of faint active galactic nuclei (AGNs) in the early Universe is key for understanding the formation of supermassive black holes (SMBHs) and determining their role in cosmic reionization. We perform a spectroscopic search for broad Hα emitters at z ≈ 4–6 using deep JWST/NIRCam imaging and wide field slitless spectroscopy from the EIGER and FRESCO surveys. We identify 20 Hα lines at z = 4.2–5.5 that have broad components with line widths from ∼1200–3700 km s−1, contributing ∼30%–90% of the total line flux. We interpret these broad components as being powered by accretion onto SMBHs with implied masses ∼107–8 M ⊙. In the UV luminosity range M UV,AGN+host = −21 to −18, we measure number densities of ≈10−5 cMpc−3. This is an order of magnitude higher than expected from extrapolating quasar UV luminosity functions (LFs). Yet, such AGN are found in only <1% of star-forming galaxies at z ∼ 5. The number density discrepancy is much lower when compared to the broad Hα LF. The SMBH mass function agrees with large cosmological simulations. In two objects, we detect complex Hα profiles that we tentatively interpret as caused by absorption signatures from dense gas fueling SMBH growth and outflows. We may be witnessing early AGN feedback that will clear dust-free pathways through which more massive blue quasars are seen. We uncover a strong correlation between reddening and the fraction of total galaxy luminosity arising from faint AGN. This implies that early SMBH growth is highly obscured and that faint AGN are only minor contributors to cosmic reionization.

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“…The attenuation (thus reddening of the stellar continuum), combined with high SFRs, is what is needed to reproduce the photometry of a z > 10 Lyman break. Note that allowing A V to vary by up to 6 generates another cluster of possible solutions at z < 1 with A V ∼ 5; these are largely unphysical, as they would imply extreme attenuation and high SFRs in low-mass dwarf galaxies (Bisigello et al 2023). If such a phenomenon were common, submillimeter number counts would likely be dominated by such sources, and they are not (Casey et al 2014;Fujimoto et al 2016).…”

Section: The Possibility Of Low-redshift Interlopersmentioning

confidence: 99%

COSMOS-Web: Intrinsically Luminous z ≳ 10 Galaxy Candidates Test Early Stellar Mass Assembly

Casey,

Akins,

Shuntov

et al. 2024

ApJ

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We report the discovery of 15 exceptionally luminous 10 ≲ z ≲ 14 candidate galaxies discovered in the first 0.28 deg2 of JWST/NIRCam imaging from the COSMOS-Web survey. These sources span rest-frame UV magnitudes of −20.5 > M UV > −22, and thus constitute the most intrinsically luminous z ≳ 10 candidates identified by JWST to date. Selected via NIRCam imaging, deep ground-based observations corroborate their detection and help significantly constrain their photometric redshifts. We analyze their spectral energy distributions using multiple open-source codes and evaluate the probability of low-redshift solutions; we conclude that 12/15 (80%) are likely genuine z ≳ 10 sources and 3/15 (20%) likely low-redshift contaminants. Three of our z ∼ 12 candidates push the limits of early stellar mass assembly: they have estimated stellar masses ∼ 5 × 109 M ⊙, implying an effective stellar baryon fraction of ϵ ⋆ ∼ 0.2−0.5, where ϵ ⋆ ≡ M ⋆/(f b M halo). The assembly of such stellar reservoirs is made possible due to rapid, burst-driven star formation on timescales < 100 Myr where the star formation rate may far outpace the growth of the underlying dark matter halos. This is supported by the similar volume densities inferred for M ⋆ ∼ 1010 M ⊙ galaxies relative to M ⋆ ∼ 109 M ⊙—both about 10−6 Mpc−3—implying they live in halos of comparable mass. At such high redshifts, the duty cycle for starbursts would be of order unity, which could cause the observed change in the shape of the UV luminosity function from a double power law to a Schechter function at z ≈ 8. Spectroscopic redshift confirmation and ensuing constraints of their masses will be critical to understand how, and if, such early massive galaxies push the limits of galaxy formation in the Lambda cold dark matter paradigm.

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Delving deep: A population of extremely dusty dwarfs observed by JWST

Cited by 12 publications

References 73 publications

Searching for Planets Orbiting Fomalhaut with JWST/NIRCam

Searching for Planets Orbiting Fomalhaut with JWST/NIRCam

Little Red Dots: An Abundant Population of Faint Active Galactic Nuclei at z ∼ 5 Revealed by the EIGER and FRESCO JWST Surveys

COSMOS-Web: Intrinsically Luminous z ≳ 10 Galaxy Candidates Test Early Stellar Mass Assembly

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