A Wide-field Near- and Mid-Infrared Census of Young Stars in NGC 6334

Abstract

This paper presents a study of the rate and efficiency of star formation in the NGC 6334 star forming region. We obtained observations at J, H, and Ks taken with the NOAO Extremely Wide-Field Infrared Imager (NEWFIRM) and combined them with observations taken with the Infrared Array Camera (IRAC) camera on the Spitzer Space Telescope at wavelengths λ = 3.6, 4.5, 5.8, and 8.0 μm. We also analyzed previous observations taken at 24 μm using the Spitzer MIPS camera as part of the MIPSGAL survey. We have produced a point source catalog with >700,000 entries. We have identified 2283 YSO candidates, 375 Class I YSOs and 1908 Class II YSOs using a combination of existing IRAC-based color classification schemes that we have extended and validated to the near-IR for use with warm Spitzer data. We have identified multiple new sites of ongoing star formation activity along filamentary structures extending tens of parsecs beyond the central molecular ridge of NGC 6334. By mapping the extinction we derived an estimate for the gas mass, 2.2 x 10^5 M_sun. The heavy concentration of protostars along the dense filamentary structures indicates that NGC 6334 may be undergoing a "mini-starburst" event with Σ{SFR}>8.2 M_sun Myr^-1 pc^-2 and SFE>0.10. We have used these estimates to place NGC 6334 in the Kennicutt-Schmidt diagram to help bridge the gap between observations of local low-mass star forming regions and star formation in other galaxies.

References in corpus (37)

• The Global Schmidt Law in Star Forming Galaxies
• The Infrared Array Camera (IRAC) for the Spitzer Space Telescope
• The Spitzer Space Telescope Mission
• Interstellar Dust Grains
• The Spitzer c2d Legacy Results: Star Formation Rates and Efficiencies; Evolution and Lifetimes
• GLIMPSE: I. A SIRTF Legacy Project to Map the Inner Galaxy
• Interpreting Spectral Energy Distributions from Young Stellar Objects. I. A grid of 200,000 YSO model SEDs
• Clouds, filaments and protostars: the Herschel Hi-GAL Milky Way
• On the Star Formation Rates in Molecular Clouds
• A Spitzer Survey of Young Stellar Clusters within One Kiloparsec of the Sun: Cluster Core Extraction and Basic Structural Analysis
• Spitzer Survey of the Large Magellanic Cloud, Surveying the Agents of a Galaxy's Evolution (SAGE) I: Overview and Initial Results
• The Star Formation Rate and Gas Surface Density Relation in the Milky Way: Implications for Extragalactic Studies
• The Spitzer Space Telescope Survey of the Orion A & B Molecular Clouds - Part I: A Census of Dusty Young Stellar Objects and a Study of their Mid-IR Variability
• A Minimum Column Density of 1 g cm^-2 for Massive Star Formation
• Mapping the interstellar dust with near-infrared observations: An optimized multi-band technique
• Intrinsically Red Sources observed by Spitzer in the Galactic Mid-Plane
• A Correlation Between Surface Densities of Young Stellar Objects and Gas in Eight Nearby Molecular Clouds
• The global gas and dust budget of the Large Magellanic Cloud: AGB stars and supernovae, and the impact on the ISM evolution
• From Massive Protostars to a Giant HII Region: Submillimeter Imaging of the Galactic Mini-starburst W43
• Clustered and Triggered Star Formation in W5: Observations with Spitzer
• Chemical abundances in LMC stellar populations I. The Inner disk sample Based on observations collected at the VLT UT2 telescope
• The California Molecular Cloud
• The SAGE-Spec Spitzer Legacy program: The life-cycle of dust and gas in the Large Magellanic Cloud. Point source classification I
• Luminosity Functions of Spitzer Identified Protostars in Nine Nearby Molecular Clouds
• The NGC 7129 Young Stellar Cluster: A Combined Spitzer, MMT, and 2MASS Census of Disks, Protostars, and Outflows
• The Spitzer Survey of Interstellar Clouds in the Gould Belt. III. A Multi-Wavelength View of Corona Australis
• Spitzer observations of the Massive star forming complex S254-S258: structure and evolution
• The Nature of Transition Circumstellar Disks II. Southern Molecular Clouds
• The Spitzer survey of interstellar clouds in the Gould Belt. II. The Cepheus Flare observed with IRAC and MIPS
• The optically bright post-AGB population of the LMC
• Digging into NGC 6334I(N): Multiwavelength Imaging of a Massive Protostellar Cluster
• Stellar Clusters in the NGC 6334 Star Forming Complex
• A Deep Multicolor Survey. VI. Near-Infrared Observations, Selection Effects, and Number Counts
• Detection of Star Formation in the Unusually Cold Giant Molecular Cloud G216
• The Spitzer Survey of Interstellar Clouds in the Gould Belt. V. Ophiuchus North Observed with IRAC and MIPS
• The Spitzer Survey of Interstellar Clouds in the Gould Belt. IV. Lupus V and VI Observed with IRAC and MIPS
• The Spitzer-IRAC Point Source Catalog of the Vela-D Cloud

Cited by in corpus (36)

• An extraordinary outburst in the massive protostellar system NGC6334I-MM1: quadrupling of the millimeter continuum
• The earliest phases of high-mass star formation, as seen in NGC 6334 by \emph{Herschel}
• Identification of Young Stellar Object candidates in the $Gaia$ DR2 x AllWISE catalogue with machine learning methods
• The Extraordinary Outburst in the Massive Protostellar System NGC6334I-MM1: Emergence of Strong 6.7 GHz Methanol Masers
• A Masing Event in NGC6334I: Contemporaneous Flaring of Hydroxyl, Methanol and Water Masers
• Star-forming content of the giant molecular filaments in the Milky Way
• Subarcsecond Imaging of the NGC 6334 I(N) Protocluster: Two Dozen Compact Sources and a Massive Disk Candidate
• The Massive Protostellar Cluster NGC6334I at 220 AU Resolution: Discovery of Further Multiplicity, Diversity and a Hot Multi-Core
• Probing fragmentation and velocity sub-structure in the massive NGC 6334 filament with ALMA
• Testing the role of environmental effects on the initial mass function of low-mass stars
• A feedback-driven bubble G24.136+00.436: a possible site of triggered star formation
• Molecular clouds in the NGC 6334 and NGC 6357 region; Evidence for a 100 pc-scale cloud-cloud collision triggering the Galactic mini-starbursts
• Physical Properties of the star-forming clusters in NGC 6334
• Star formation in W3 - AFGL333: Young stellar content, properties and roles of external feedback
• The stellar contents and star formation in the NGC 7538 region
• ALMA observations of NGC 6334S $-$ I: Forming massive stars and cluster in subsonic and transonic filamentary clouds
• The Massive Star-Forming Regions Omnibus X-Ray Catalog, Second Installment
• ALMA observations of NGC 6334S. II. Subsonic and Transonic Narrow Filaments in a High-mass Star Formation Cloud
• The disintegrating old open cluster Czernik 3
• Strong dependence of the physical properties of cores on spatial resolution in observations and simulations
• Young Stellar Objects in the Massive Star Forming Region W49
• Lack of high-mass prestellar cores in the starless MDCs of NGC6334
• Multi-scale physical properties of NGC 6334 as revealed by local relative orientations between magnetic fields, density gradients, velocity gradients, and gravity
• A WISE Census of Young Stellar Objects in Perseus OB2 Association
• Identifying Young Stellar Objects in the Outer Galaxy: l = 224 deg Region in Canis Major
• A novel survey for young substellar objects with the W-band filter VI: Spectroscopic census of sub-stellar members and the IMF of $\sigma$ Orionis cluster
• A Low-mass Cold and Quiescent Core Population in a Massive Star Protocluster
• The Bulge Asymmetries and Dynamical Evolution (BAaDE) SiO Maser Survey at 86 GHz with ALMA
• Large scale star formation in Auriga region
• MAGMO: Polarimetry of 1720-MHz OH Masers towards Southern Star Forming Regions
• Young Stellar Populations in MYStIX Star Forming Regions: Candidate Protostars
• The richness of compact radio sources in NGC 6334D to F
• Interstellar Nitrogen Isotope Ratios: New NH3 Data from the Galactic Center out to the Perseus Arm
• The SPHEREx Target List of Ice Sources (SPLICES)
• Massive Stars in Molecular Clouds Rich in High-energy Sources: The Bridge of G332.809-0.132 and CS 78 in NGC 6334
• Unraveling the Spectral Energy Distributions of Clustered YSOs