MIRI/JWST observations reveal an extremely obscured starburst in the z=6.9 system SPT0311-58

Abstract

Using MIRI on-board JWST we present mid-infrared sub-arcsec imaging (MIRIM) and spectroscopy (MRS) of the hyperluminous infrared system SPT0311-58 at z=6.9. MIRI observations are compared with existing ALMA far-infrared continuum and [CII]158$\mu$m imaging. Even though the ALMA observations suggests very high star formation rates (SFR) in the eastern (E) and western (W) galaxies of the system, the H$\alpha$ line is not detected. This, together with the detection of the Pa$\alpha$ line, implies very high optical nebular extinction with lower limits of 4.2 (E) and 3.9 mag (W), and even larger 5.6 (E) and 10.0 (W) for SED derived values. The extinction-corrected Pa$\alpha$ SFRs are 383 and 230M${}_{\odot }$yr${}^{-1}$ for the E and W galaxies, respectively. This represents 50% of the SFRs derived from the [CII]158$\mu$m line and infrared light for the E galaxy and as low as 6% for the W galaxy. The MIRI observations reveal a clumpy stellar structure, with each clump having 3 to 5 $\times$10${}^9$M${}_{\odot }$, leading to a total stellar mass of 2.0 and 1.5$\times$10${}^{10}$M${}_{\odot }$ for the E and W galaxies, respectively. The specific SFR in the stellar clumps ranges from 25 to 59Gyr${}^{-1}$, which are 3 to 10 times larger than the values measured in galaxies of similar mass at redshifts 6 to 8. The overall gas mass fraction is $M_{\mathrm{gas}}$/$M_{\ast }\sim 3$, similar to that of z=4.5-6 star-forming galaxies. The observed properties of SPT0311-58 such as the clumpy distribution at sub(kpc) scales and the very high average extinction are similar to those observed in low- and intermediate-z LIRGs and ULIRGs, even though SPT0311-58 is observed only 800 Myr after the Big Bang. Massive, heavily obscured, clumpy starburst systems like SPT0311-58 likely represent the early phases in the formation of massive high-z bulge/spheroids and luminous quasars.

18 pages, 8 figures, final published version in A&A

References in corpus (36)

• Gaia Data Release 3: Summary of the content and survey properties
• Cosmic Star Formation History
• Infrared Emission from Interstellar Dust. IV. The Silicate-Graphite-PAH Model in the Post-Spitzer Era
• A Cosmological Framework for the Co-Evolution of Quasars, Supermassive Black Holes, and Elliptical Galaxies: I. Galaxy Mergers & Quasar Activity
• A Highly Consistent Framework for the Evolution of the Star-Forming "Main Sequence" from z~0-6
• Formation of Massive Galaxies at High Redshift: Cold Streams, Clumpy Disks and Compact Spheroids
• Binary Population and Spectral Synthesis Version 2.1: construction, observational verification and new results
• A Dust-Obscured Massive Maximum-Starburst Galaxy at a Redshift of 6.34
• A Cosmological Framework for the Co-Evolution of Quasars, Supermassive Black Holes, and Elliptical Galaxies: II. Formation of Red Ellipticals
• Galaxy growth in a massive halo in the first billion years of cosmic history
• Near-Infrared and Star-forming properties of Local Luminous Infrared Galaxies
• Kiloparsec-scale ALMA Imaging of [CII] and Dust Continuum Emission of 27 Quasar Host Galaxies at z~6
• ISM properties of a Massive Dusty Star-Forming Galaxy discovered at z ~ 7
• Automated Mining of the ALMA Archive in the COSMOS Field (A3COSMOS): II. Cold Molecular Gas Evolution out to Redshift 6
• The ALPINE-ALMA [CII] survey: Molecular gas budget in the Early Universe as traced by [CII]
• Characterizing the UV-to-NIR shape of the dust attenuation curve of IR luminous galaxies up to z$\sim$2
• Dual constraints with ALMA: new [O III] 88 $\mu$m and dust-continuum observations reveal the ISM conditions of luminous LBGs at $z\sim 7$
• COLDz: A High Space Density of Massive Dusty Starburst Galaxies ~1 Billion Years after the Big Bang
• Understanding the 8 micron vs. Pa-alpha relationship on sub-arcsecond scales in Luminous Infrared Galaxies
• The ALMA Spectroscopic Survey in the Hubble Ultra Deep Field: The nature of the faintest dusty star-forming galaxies
• ALMA 200 pc imaging of a z~7 quasar reveals a compact, disk-like host galaxy
• A dense, solar metallicity ISM in the z=4.2 dusty star-forming galaxy SPT0418-47
• The assembly of dusty galaxies at $z\ge 4$: the build-up of stellar mass and its scaling relations with hints from early JWST data
• Clumpy and Extended Starbursts in the Brightest Unlensed Submillimeter Galaxies
• X-shooter Spectroscopy and HST Imaging of 15 Ultra Massive Quiescent Galaxies at $z\gtrsim 2$
• ALMA Lensing Cluster Survey: an ALMA galaxy signposting a MUSE galaxy group at z=4.3 behind 'El Gordo'
• First Peek with JWST/NIRCam Wide-Field Slitless Spectroscopy: Serendipitous Discovery of a Strong [O III]/H$\alpha$ Emitter at $z=6.11$
• Molecular Line Observations in Two Dusty Star-Forming Galaxies at z = 6.9
• Merger induced clump formation in distant infrared luminous starburst galaxies
• ALMACAL II: Extreme star-formation-rate densities in a pair of dusty starbursts at $z=3.442$ revealed by ALMA 20-milliarcsec resolution imaging
• Chaotic and Clumpy Galaxy Formation in an Extremely Massive Reionization-Era Halo
• The redshift and star formation mode of AzTEC2: a pair of massive galaxies at $z=4.63$
• The Ionised- and Cool-Gas Content of The BR1202-0725 System as seen by MUSE and ALMA
• Compact molecular gas emission in local LIRGs among low- and high-z galaxies
• High Resolution HST Imaging Survey of Local Star-Forming Galaxies I: Spatially-Resolved Obscured Star Formation with H$\alpha$ and Paschen-$\beta$ Recombination Lines
• [NII] fine-structure emission at 122 and 205um in a galaxy at z=2.6: a globally dense star-forming interstellar medium

Cited by in corpus (15)

• AGN Selection and Demographics: A New Age with JWST/MIRI
• GA-NIFS: The core of an extremely massive proto-cluster at the Epoch of Reionization probed with JWST/NIRSpec
• GA-NIFS: Early-stage feedback in a heavily obscured AGN at $z=4.76$
• JWST MIRI Flight Performance: Imaging
• Insight into the Starburst Nature of Galaxy GN-z11 with JWST MIRI Spectroscopy
• Spatially-resolved H$\alpha$ and ionizing photon production efficiency in the lensed galaxy MACS1149-JD1 at a redshift of 9.11
• Uncovering the stellar structure of the dusty star-forming galaxy GN20 at z=4.055 with MIRI/JWST
• JWST's PEARLS: resolved study of the stellar and dust components in starburst galaxies at cosmic noon
• The Manhattan Suite: Accelerated galaxy evolution in the early Universe
• Clumpy star formation and an obscured nuclear starburst in the luminous dusty z=4 galaxy GN20 seen by MIRI/JWST
• JWST/MIRI unveils the stellar component of the GN20 dusty galaxy overdensity at $z$=4.05
• What is the nature of Little Red Dots and what is not, MIRI SMILES edition
• Spatially resolved H$\alpha$ emission in B14-65666: compact starbursts, ionizing efficiency and gas kinematics in an advanced merger at the Epoch of Reionization
• Formation of Substructure in Luminous Submillimeter Galaxies (FOSSILS): Evidence of Multiple Pathways to Trigger Starbursts in Luminous Submillimeter Galaxies
• MIRI spectrophotometry of GN-z11: Detection and nature of an optical red continuum component