On the Diagnostic Power of FIR/Sub-mm SED Fitting in Massive Galactic Molecular Clumps

Abstract

We used FIR and submillimeter continuum data from Herschel and the Atacama Pathfinder EXperiment (APEX) to fit pixel-by-pixel modified Planck SEDs to prestellar and protostellar clumps in the Census of High- and Medium-mass Protostars (CHaMP) ($280^{\circ }<\ell <300^{\circ }$, $-4^{\circ }<b<+2^{\circ }$). We present maps of dust temperature ($T_{\text{d}}$) and H${}_2$ column density (\ncol) for molecular clumps in the Carina Nebula complex (Regions 9 through 11), and surrounding RCW 64 (Region 26). We compare the column densities of CO and H${}_2$ to chart regional variations in their correspondence, and derive maps of the CO abundance. We find the CO abundance varies by an order of magnitude or more across each region, averaging a few$\times$10${}^{-5}$ CO per H${}_2$, and that the CO abundance distribution across each clump is correlated in both form and magnitude with environmental conditions, especially $T_{\text{d}}$. This demonstrates that no single CO abundance suffices to convert from $N_{\text{CO}}$ to \ncol, even within a single molecular cloud. We also find that $L/M$ traces $T_{\text{d}}$ almost exclusively, and therefore is not an independent star formation tracer, but minima in $T_{\text{d}}$ almost universally coincide with maxima in \ncol, implying that cooling and density enhancement must be simultaneous steps in prestellar clump evolution. Finally, based on generalized histogram N-PDFs of clump-scale (1-5 pc) and cloud-scale ($\gtrsim 10$ pc) samples, we could only obtain dual log-normal and power-law fits to $\sim 10\%$ of the clumps. The physical parameters derived from these fits approach theoretical expectations, but have largely unknown uncertainties, so we advise treating the results of N-PDF fitting with caution.

arXiv comment27 pages, 23 figures (+7 pages, 13 figures in appendix); submitted to MNRAS

References in corpus (106)

• Galactic Stellar and Substellar Initial Mass Function
• The Wide-field Infrared Survey Explorer (WISE): Mission Description and Initial On-orbit Performance
• Embedded Clusters in Molecular Clouds
• Herschel Space Observatory - An ESA facility for far-infrared and submillimetre astronomy
• The Photodetector Array Camera and Spectrometer (PACS) on the Herschel Space Observatory
• The Herschel-SPIRE instrument and its in-flight performance
• The CO-to-H2 Conversion Factor
• The Milky Way in Molecular Clouds: A New Complete CO Survey
• Infrared Emission from Interstellar Dust. II. The Diffuse Interstellar Medium
• Toward Understanding Massive Star Formation
• A General Theory of Turbulence-Regulated Star Formation, From Spirals to ULIRGs
• Trigonometric Parallaxes of Massive Star Forming Regions: VI. Galactic Structure, Fundamental Parameters and Non-Circular Motions
• The Stellar IMF from Turbulent Fragmentation
• Cold Dark Clouds: The Initial Conditions for Star Formation
• Interpreting Spectral Energy Distributions from Young Stellar Objects. II. Fitting observed SEDs using a large grid of pre-computed models
• Comparing the statistics of interstellar turbulence in simulations and observations: Solenoidal versus compressive turbulence forcing
• Clouds, filaments and protostars: the Herschel Hi-GAL Milky Way
• The Dark Molecular Gas
• ATLASGAL - The APEX Telescope Large Area Survey of the Galaxy at 870 microns
• New Interstellar Dust Models Consistent with Extinction, Emission, and Abundance Constraints
• MAMBO Mapping of Spitzer c2d Small Clouds and Cores
• Hi-GAL: the Herschel infrared Galactic Plane Survey
• Analytical theory for the initial mass function: CO clumps and prestellar cores
• The Density Probability Distribution in Compressible Isothermal Turbulence: Solenoidal versus Compressive Forcing
• High-Mass Star and Massive Cluster Formation in the Milky Way
• High-Mass Proto-Stellar Candidates - I : The Sample and Initial Results
• Probing the evolution of molecular cloud structure: From quiescence to birth
• The global dust SED: Tracing the nature and evolution of dust with DustEM
• N2H+ and C18O Depletion in a Cold Dark Cloud
• Density probability distribution in one-dimensional polytropic gas dynamics
• The Southern Galactic Plane Survey: HI Observations and Analysis
• ATLASGAL --- properties of a complete sample of Galactic clumps
• CO Isotopologues in the Perseus Molecular Cloud Complex: the X-Factor and Regional Variations
• Photodesorption of ices I: CO, N2 and CO2
• The Large APEX Bolometer Camera LABOCA
• Analytical star formation rate from gravoturbulent fragmentation
• What determines the density structure of molecular clouds ? A case study of Orion B with Herschel
• Hi-GAL, the Herschel infrared Galactic Plane Survey: photometric maps and compact source catalogues. First data release for Inner Milky Way: +68°> l > -70°
• Evolution and fate of very massive stars
• Non-Standard Grain Properties, Dark Gas Reservoir, and Extended Submillimeter Excess, Probed by Herschel in the Large Magellanic Cloud
• The Milky Way Project First Data Release: A Bubblier Galactic Disk
• Supersonic turbulence in the ISM: stellar extinction determinations as probes of the structure and dynamics of dark clouds
• FOREST Unbiased Galactic plane Imaging survey with the Nobeyama 45-m telescope (FUGIN) I: Project Overview and Initial Results
• Planck Early Results: The Galactic Cold Core Population revealed by the first all-sky survey
• A census of dense cores in the Aquila cloud complex: SPIRE/PACS observations from the Herschel Gould Belt survey
• A Census of the Carina Nebula. I: Cumulative Energy Input from Massive Stars
• Gravity or turbulence? II. Evolving column density PDFs in molecular clouds
• Dynamically Driven Evolution of the Interstellar Medium in M51
• Star Formation in Massive Clusters via the Wilkinson Microwave Anisotropy Probe and the Spitzer Glimpse Survey
• The Degree of CO Depletion in Pre-stellar Cores
• Planck early results. XXI. Properties of the interstellar medium in the Galactic plane
• Chemical evolution in the early phases of massive star formation. I
• A Pan-Carina YSO Catalog: Intermediate-Mass Young Stellar Objects in the Carina Nebula Identified Via Mid-Infrared Excess Emission
• Thermal desorption characteristics of CO, O2 and CO2 on non-porous water, crystalline water and silicate surfaces at sub-monolayer and multilayer coverages
• Molecular clouds have power-law probability distribution functions
• The Probability Distribution Function of Column Density in Molecular Clouds
• Understanding star formation in molecular clouds I. Effects of line-of-sight contamination on the column density structure
• Vindicating single-T modified blackbody fits to Herschel SEDs (Research Note)
• First results from the Herschel Gould Belt Survey in Taurus
• Planck Early Results: The submillimetre properties of a sample of Galactic cold clumps
• Analytical theory for the initial mass function: III time dependence and star formation rate
• ATLASGAL --- Complete compact source catalogue: 280\degr\ $<\ell <$ 60\degr
• The Three-mm Ultimate Mopra Milky Way Survey. I. Survey Overview, Initial Data Releases, and First Results
• CO Abundance Variations in the Orion Molecular Cloud
• Mapping Large-Scale CO Depletion in a Filamentary Infrared Dark Cloud
• Ionization compression impact on dense gas distribution and star formation, Probability density functions around H ii regions as seen by Herschel
• The Column Density Variance-Sonic Mach Number Relationship
• High-Mass Cloud Cores in the eta Carinae Giant Molecular Cloud
• Clementine Observations of the Zodiacal Light and the Dust Content of the Inner Solar System
• Calibration of evolutionary diagnostics in high-mass star formation
• The shapes of column density PDFs - The importance of the last closed contour
• The Galactic Census of High- and Medium-mass Protostars. I. Catalogues and First Results from Mopra HCO+ Maps
• A MAD view of Trumpler 14
• Herschel far-infrared observations of the Carina Nebula complex I: Introduction and global cloud structure
• High CO depletion in southern infrared-dark clouds
• Photometric study of the young open cluster NGC 3293
• Herschel far-infrared observations of the Carina Nebula Complex. - III: Detailed cloud structure and feedback effects
• Opening the Treasure Chest: A Newborn Star Cluster Emerges from its Dust Pillar in Carina
• 2MASS wide field extinction maps: V. Corona Australis
• A Chandra ACIS Study of the Young Star Cluster Trumpler 15 in Carina and Correlation with Near-infrared Sources
• The CO-to-H2 Conversion Factor across the Perseus Molecular Cloud
• The Anatomy of the Column Density Probability Distribution Function (N-PDF)
• CO line ratios in molecular clouds: the impact of environment
• The Relationship Between the Dust and Gas-Phase CO Across the California Molecular Cloud
• Star formation towards the Galactic HII region RCW120
• Herschel far-infrared observations of the Carina Nebula complex II: The embedded young stellar and protostellar population
• The Giant Pillars of the Carina Nebula
• Variations between Dust and Gas in the Diffuse Interstellar Medium
• The Galactic Census of High- and Medium-mass Protostars. II. Luminosities and Evolutionary States of a Complete Sample of Dense Gas Clumps
• Circumnuclear Multi-phase Gas in Circinus Galaxy I: Non-LTE calculations of CO lines
• Discovering young stars in the Gum 31 region with infrared observations
• CO depletion: a microscopic perspective
• Discovery of Large-Scale Gravitational Infall in a Massive Protostellar Cluster
• The Galactic Census of High- and Medium-mass Protostars. IV. Molecular Clump Radiative Transfer, Mass Distributions, Kinematics, and Dynamical Evolution
• Herschel observations of the Galactic HII region RCW 79
• Simultaneous spectral energy distribution and near-infrared interferometry modeling of HD 142666
• Millimetre-Wave and Near-Infrared Signposts of Massive Molecular Clump Evolution and Star Cluster Formation
• The VISTA Carina Nebula Survey II. Spatial distribution of the infrared-excess-selected young stellar population
• The Galactic Census of High- and Medium-mass Protostars. III ${}^{12}$CO Maps and Physical Properties of Dense Clump Envelopes and their Embedding GMCs
• Notes on Star Formation
• Spectroscopic Confirmation of the Dragonfish Association: The Galaxy's Most Luminosity OB Association
• Variations between Dust and Gas in the Diffuse Interstellar Medium. 2. Search for Cold Gas
• A Candidate for the Most Luminous OB Association in the Galaxy
• A CO survey on a sample of Herschel cold clumps
• Probing the Dragonfish star-forming complex: the ionizing population of the young massive cluster Mercer 30
• Molecular gas associated with IRAS 10361-5830

Cited by in corpus (8)

• The SEDIGISM survey: first data release and overview of the Galactic structure
• The Physical Drivers and Observational Tracers of CO-to-H2 Conversion Factor Variations in Nearby Barred Galaxy Centers
• The SEDIGISM survey: a search for molecular outflows
• The SEDIGISM survey: Molecular cloud morphology. I. Classification and star formation
• HII regions and high-mass starless clump candidates I: Catalogs and properties
• Census of High- and Medium-mass Protostars V. CO Abundance and the Galactic $X_{\text{CO}}$ Factor
• Linking High- and Low-Mass Star Formation: Observation-Based Continuum Modelling and Physical Conditions
• SOFIA and ALMA Investigate Magnetic Fields and Gas Structures in Massive Star Formation: The Case of the Masquerading Monster in BYF 73