Herschel-PACS observations of [OI]63um towards submillimetre galaxies at z~1

Abstract

We present Herschel-PACS spectroscopy of the [OI]63um far-infrared cooling line from a sample of six unlensed and spectroscopically-confirmed 870um-selected submillimetre (submm) galaxies (SMGs) at 1.1<z<1.6 from the LABOCA Extended Chandra Deep Field South (ECDFS) Submm Survey (LESS). This is the first survey of [OI]63um, one of the main photodissociation region (PDR) cooling lines, in SMGs. New high-resolution ALMA interferometric 870um continuum imaging confirms that these six Herschel-targeted SMG counterparts are bona fide sources of submm emission. We detect [OI]63um in two SMGs with a SNR >3, tentatively detect [OI]63um in one SMG, and constrain the line flux for the non-detections. We also exploit the combination of submm continuum photometry from 250-870um and our new PACS continuum measurements to constrain the far-infrared (FIR) luminosity, L_FIR, in these SMGs to < 30%. We find that SMGs do not show a deficit in their [OI]63um-to-far-infrared continuum luminosity ratios (with ratios ranging from ~0.5-1.5%), similar to what was seen previously for the [CII]158um-to-FIR ratios in SMGs. These observed ratios are about an order of magnitude higher than what is seen typically for local ultra luminous infrared galaxies (ULIRGs), which adds to the growing body of evidence that SMGs are not simply `scaled up' versions of local ULIRGs. Rather, the PDR line-to-L_FIR ratios suggest that the star formation modes of SMGs are likely more akin to that of local normal (lower-luminosity) star-forming galaxies, with the bulk of the star formation occurring in extended regions, galaxy-scale (~kpc) in size. These observations represent the first step towards a census of the major PDR cooling lines in typical SMGs that will be attainable with ALMA, enabling detailed modelling to probe the global properties of the star formation and the evolutionary status of SMGs.

13 pages, 3 figures, accepted for publication in MNRAS

References in corpus (12)

• A survey of molecular gas in luminous sub-millimetre galaxies
• Diagnostics of irradiated dense gas in galaxy nuclei. II. A grid of XDR and PDR models
• Mid-Infrared Spectral Diagnosis of Submillimeter Galaxies
• Intense Star Formation within Resolved Compact Regions in a Galaxy at z=2.3
• SHARC-2 350 Micron Observations of Distant Submillimeter Selected Galaxies
• The SCUBA HAlf Degree Extragalactic Survey (SHADES) - III. Identification of radio and mid-infrared counterparts to submillimetre galaxies
• The Large APEX Bolometer Camera LABOCA
• A Compendium of Far-Infrared Line and Continuum Emission for 227 Galaxies Observed by the Infrared Space Observatory
• The SCUBA HAlf Degree Extragalactic Survey (SHADES) -- VI. 350 micron mapping of submillimetre galaxies
• The Physical Scale of the Far-Infrared Emission in the Most Luminous Submillimeter Galaxies
• High-resolution radio observations of submillimetre galaxies
• Physical conditions of the interstellar medium of high-redshift, strongly lensed submillimetre galaxies from the Herschel-ATLAS

Cited by in corpus (33)

• Cool Gas in High Redshift Galaxies
• Dusty Star-Forming Galaxies at High Redshift
• The applicability of FIR fine-structure lines as Star Formation Rate tracers over wide ranges of metallicities and galaxy types
• An ALMA Survey of Submillimeter Galaxies in the Extended Chandra Deep Field South: The Redshift Distribution and Evolution of Submillimeter Galaxies
• An ALMA survey of submillimeter galaxies in the Extended Chandra Deep Field South: Source catalog and multiplicity
• Far-infrared Fine-Structure Line Diagnostics of Ultraluminous Infrared Galaxies
• The 2 Ms Chandra Deep Field-North Survey and the 250 ks Extended Chandra Deep Field-South Survey: Improved Point-Source Catalogs
• An ALMA survey of submillimetre galaxies in the Extended Chandra Deep Field South: Spectroscopic redshifts
• An ALMA Survey of Submillimeter Galaxies in the Extended Chandra Deep Field South: The AGN Fraction and X-ray Properties of Submillimeter Galaxies
• An ALMA/NOEMA survey of the molecular gas properties of high-redshift star-forming galaxies
• Far-infrared surveys of galaxy evolution
• Strong C+ emission in galaxies at z~1-2: Evidence for cold flow accretion powered star formation in the early Universe
• Varying [CII]/[NII] line ratios in the interacting system BR1202-0725 at z=4.7
• The interstellar medium in high-redshift submillimeter galaxies as probed by infrared spectroscopy
• A dense, solar metallicity ISM in the z=4.2 dusty star-forming galaxy SPT0418-47
• Spectroscopically resolved far-IR observations of the massive star-forming region G5.89--0.39
• SPT 0538-50: Physical conditions in the ISM of a strongly lensed dusty star-forming galaxy at z=2.8
• The XMM-Newton deep survey in the Chandra Deep Field South. III. Point source catalogue and number counts in the hard X-rays
• A comprehensive view of the interstellar medium in a quasar host galaxy at z~6.4
• Exploring the early dust-obscured phase of galaxy formation with blind mid-/far-IR spectroscopic surveys
• The 2nd Generation z(Redshift) and Early Universe Spectrometer Part I: First-light observation of a highly lensed local-ULIRG analog at high-z
• Resolving Star Formation on Sub-Kiloparsec Scales in the High-Redshift Galaxy SDP.11 Using Gravitational Lensing
• Neutral carbon and highly excited CO in a massive star-forming main sequence galaxy at z=2.2
• First detection of the [OI] 63-um emission from a redshift 6 dusty galaxy
• The ALMA Patchy Deep Survey: A blind search for [CII] emitters at z~4.5
• Multi-Phase ISM in the z = 5.7 Hyperluminous Starburst SPT0346-52
• Diagnosing the interstellar medium of galaxies with far-infrared emission lines II. [C II], [O I], [O III], [N II] and [N III] up to z=6
• Properties of Interstellar Medium In Infrared Bright QSOs Probed by [O I]63 micron and [C II]158 micron Emission Lines
• Observations of [OI]63micron line emission in main-sequence galaxies at z~1.5
• Detection of the [O I] 63 $\mu$m emission line from the $z=6.04$ quasar J2054-0005
• High$-z$ [OI] emission lines: ColdSIM simulations and ALMA observations
• Tracing obscured galaxy build-up at high redshift using deep radio surveys
• Uncovering the absorbed atomic Universe with the [OI]63um line