The JCMT Nearby Galaxies Legacy Survey: SCUBA-2 observations of nearby galaxies

Abstract

We present 850$\mu$m observations of a sample of 8 nearby spiral galaxies, made using the SCUBA-2 camera on the James Clerk Maxwell Telescope (JCMT) as part of the JCMT Nearby Galaxies Legacy Survey (NGLS). We corrected our data for the presence of the ${}^{12}$CO $J=3\to 2$ line in the SCUBA-2 850$\mu$m bandwidth using NGLS HARP data, finding a typical ${}^{12}$CO contribution of $\sim 20$%. We measured dust column densities, temperatures and opacity indices by fitting spectral energy distributions constructed from SCUBA-2 and archival Herschel observations, and used archival GALEX and Spitzer data to make maps of surface density of star formation (${\Sigma }_{\mathrm{SFR}}$). Typically, comparing SCUBA-2-derived H${}_2$ surface densities (${\Sigma }_{{\mathrm{H}}_2}$) to ${\Sigma }_{\mathrm{SFR}}$ gives shallow star formation law indices within galaxies, with SCUBA-2-derived values typically being sublinear and Herschel-derived values typically being broadly linear. This difference is likely due to the effects of atmospheric filtering on the SCUBA-2 data. Comparing the mean values of ${\Sigma }_{{\mathrm{H}}_2}$ and ${\Sigma }_{\mathrm{SFR}}$ of the galaxies in our sample returns a steeper star formation law index, broadly consistent with both the Kennicutt-Schmidt value of 1.4 and linearity. Our results show that a SCUBA-2 detection is a good predictor of star formation. We suggest that Herschel emission traces gas in regions which will form stars on timescales $\sim 5-100$ Myr, comparable to the star formation timescale traced by GALEX and Spitzer data, while SCUBA-2 preferentially traces the densest gas within these regions, which likely forms stars on shorter timescales.

arXiv commentAccepted for publication in MNRAS. 15 pages, 12 figures, 8 tables (plus 15 pages of appendices, with 31 figures)

References in corpus (65)

• The chemical composition of the Sun
• Galactic Stellar and Substellar Initial Mass Function
• The Global Schmidt Law in Star Forming Galaxies
• Star Formation in the Milky Way and Nearby Galaxies
• Theory of Star Formation
• Interstellar Dust Grains
• The Herschel-SPIRE instrument and its in-flight performance
• The CO-to-H2 Conversion Factor
• Infrared Emission from Interstellar Dust. IV. The Silicate-Graphite-PAH Model in the Post-Spitzer Era
• The Star Formation Efficiency in Nearby Galaxies: Measuring Where Gas Forms Stars Effectively
• The Star Formation Law in Nearby Galaxies on Sub-Kpc Scales
• Secular Evolution and the Formation of Pseudobulges in Disk Galaxies
• THINGS: The HI Nearby Galaxy Survey
• Cold Dark Clouds: The Initial Conditions for Star Formation
• High-Resolution Rotation Curves and Galaxy Mass Models from THINGS
• The Relationship Between Gas Content and Star Formation in Molecule-Rich Spiral Galaxies
• Determining Star Formation Rates for Infrared Galaxies
• SCUBA-2: The 10000 pixel bolometer camera on the James Clerk Maxwell Telescope
• HCN Survey of Normal Spiral, IR-luminous and Ultraluminous Galaxies
• An H-alpha Imaging Survey of Galaxies in the Local 11 Mpc Volume
• A Search for Extended Ultraviolet Disk (XUV-disk) Galaxies in the Local Universe
• NICMOS Imaging of Infrared-Luminous Galaxies
• Introducing GOLDMine: A new Galaxy Database on the WEB
• SCUBA-2: iterative map-making with the Sub-Millimetre User Reduction Facility
• Star Formation Rates in Molecular Clouds and the Nature of the Extragalactic Scaling Relations
• SCUBA-2: on-sky calibration using submillimetre standard sources
• The Extragalactic Distance Database: Color-Magnitude Diagrams
• HARP/ACSIS: A submillimetre spectral imaging system on the James Clerk Maxwell Telescope
• Nobeyama CO Atlas of Nearby Spiral Galaxies: Distribution of Molecular Gas in Barred and Non-barred Spiral Galaxies
• A systematic metallicity study of DustPedia galaxies reveals evolution in the dust-to-metal ratios
• The H alpha Galaxy Survey I. The galaxy sample, H alpha narrow-band observations and star formation parameters for 334 galaxies
• Dynamically Driven Evolution of the Interstellar Medium in M51
• The EDGE-CALIFA Survey: Interferometric Observations of 126 Galaxies with CARMA
• The JCMT Gould Belt Survey: First results from the SCUBA-2 observations of the Ophiuchus molecular cloud and a virial analysis of its prestellar core population
• Spectacular tails of ionised gas in the Virgo cluster galaxy NGC 4569
• The Herschel and JCMT Gould Belt Surveys: Constraining Dust Properties in the Perseus B1 Clump with PACS, SPIRE, and SCUBA-2
• DustPedia: Multiwavelength Photometry and Imagery of 875 Nearby Galaxies in 42 Ultraviolet--Microwave Bands
• The Super-linear Slope of the Spatially-Resolved Star Formation Law in NGC 3521 and NGC 5194 (M51a)
• The JCMT Nearby Galaxies Legacy Survey I. Star Forming Molecular Gas in Virgo Cluster Spiral Galaxies
• NGC 4569: recent evidence for a past ram pressure stripping event
• NGC 4254: An Act of Harassment Uncovered by the Arecibo Legacy Fast ALFA Survey
• Herschel Exploitation of Local Galaxy Andromeda (HELGA) III: The Star Formation Law in M31
• The JCMT Nearby Galaxies Legacy Survey VIII. CO data and the L(CO3-2)-L(FIR) correlation in the SINGS sample
• The ALMaQUEST Survey: V. The non-universality of kpc-scale star formation relations and the factors that drive them
• HI study of the warped spiral galaxy NGC5055: a disk/dark matter halo offset?
• The mid-life crisis of the Milky Way and M31
• The PdBI Arcsecond Whirlpool Survey (PAWS). The Role of Spiral Arms in Cloud and Star Formation
• CO Multi-line Imaging of Nearby Galaxies (COMING) IV. Overview of the Project
• Discovery of a strong spiral magnetic field crossing the inner pseudoring of NGC 4736
• Non-circular Gas Kinematics and Star Formation in the Ringed Galaxy NGC 4736
• The JCMT Gould Belt Survey: A Quantitative Comparison Between SCUBA-2 Data Reduction Methods
• The Discovery of Spiral Arms in the Starburst Galaxy M82
• The JCMT and Herschel Gould Belt Surveys: A comparison of SCUBA-2 and Herschel data of dense cores in the Taurus dark cloud L1495
• A CO J=3-2 map of M51 with HARP-B: Radial properties of the spiral structure
• The star-formation law at GMC scales in M33, the Triangulum Galaxy
• AlFoCS + Fornax3D: resolved star formation in the Fornax cluster with ALMA and MUSE
• A submillimeter exponential disk in M~51: evidence for an extended cold dust disk
• H-alpha Imaging of Early-type (Sa-Sab) Spiral Galaxies II. Global Properties
• The JCMT Gould Belt Survey: the effect of molecular contamination in SCUBA-2 observations of Orion A
• Submillimeter Continuum Properties of Cold Dust in the Inner Disk and Outflows of M82
• Submillimetre observations of the two-component magnetic field in M82
• The JCMT Gould Belt Survey: SCUBA-2 Data-Reduction Methods and Gaussian Source Recovery Analysis
• Ultraviolet Signposts of Resonant Dynamics in the Starburst-Ringed Sab Galaxy, M94 (NGC 4736)
• The effect of diffuse background on the spatially-resolved Schmidt relation in nearby spiral galaxies
• The James Clerk Maxwell Telescope Nearby Galaxies Legacy Survey IX: ${}^{12}$CO $J=3\to 2$ Observations of NGC 2976 and NGC 3351

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• NGC 3521 as the Milky Way near twin: spectral energy distribution from UV to radio decameter ranges
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