Protostellar Interferometric Line Survey of the Cygnus-X region (PILS-Cygnus) -- The role of the external environment in setting the chemistry of protostars

Abstract

(Abridged) Molecular lines are commonly detected towards protostellar sources. However, to get a better understanding of the chemistry of these sources we need unbiased molecular surveys over a wide frequency range for as many sources as possible to shed light on the origin of this chemistry, particularly any influence from the external environment. We present results from the PILS-Cygnus survey of ten intermediate- to high-mass protostellar sources in the nearby Cygnus-X complex, through high angular resolution interferometric observations over a wide frequency range. Using the Submillimeter Array (SMA), a spectral line survey of ten sources was performed in the frequency range 329-361 GHz, with an angular resolution of $\sim$1\farcs5, ($\sim$2000 AU, source distance of 1.3 kpc). Spectral modelling was performed to identify molecular emission and determine column densities and excitation temperatures for each source. We detect CH${}_3$OH towards nine of the ten sources, CH${}_3$OCH${}_3$ and CH${}_3$OCHO towards three sources, and CH${}_3$CN towards four sources. Towards five sources the chemistry is spatially differentiated (different species peak at different positions and are offset from the peak continuum emission). The chemical properties of each source do not correlate with their position in the Cygnus-X complex, nor do the distance or direction to the nearest OB associations. However, the five sources located in the DR21 filament do appear to show less line emission compared to the five sources outside the filament. This work shows how important wide frequency coverage observations are combined with high angular resolution observations for studying the protostellar environment. Based on the ten sources observed here, the external environment appears to only play a minor role in setting the chemical environment on these small scales ($<$ 2000 AU).

arXiv comment19 pages, 77 pages appendices

References in corpus (52)

• The Cologne Database for Molecular Spectroscopy, CDMS, in the Virtual Atomic and Molecular Data Centre, VAMDC
• MAMBO Mapping of Spitzer c2d Small Clouds and Cores
• High-Mass Star and Massive Cluster Formation in the Milky Way
• The ALMA Protostellar Interferometric Line Survey (PILS): First results from an unbiased submillimeter wavelength line survey of the Class 0 protostellar binary IRAS 16293-2422 with ALMA
• Testing grain-surface chemistry in massive hot-core regions
• Physical structure and CO abundance of low-mass protostellar envelopes
• Parallaxes and proper motions of interstellar masers toward the Cygnus X star-forming complex. I. Membership of the Cygnus X region
• A Rigorous Attempt to Verify Interstellar Glycine
• The earliest phases of high-mass star formation: a 3 square degree millimeter continuum mapping of Cygnus X
• Does IRAS 16293-2422 have a hot core? Chemical inventory and abundance changes in its protostellar environment
• PROSAC: A Submillimeter Array Survey of Low-Mass Protostars. I. Overview of Program: Envelopes, Disks, Outflows and Hot Cores
• Molecular Inventories and Chemical Evolution of Low-mass Protostellar Envelopes
• The ALMA-PILS survey: Isotopic composition of oxygen-containing complex organic molecules toward IRAS 16293-2422B
• Exploring Molecular Complexity with ALMA (EMoCA): Deuterated complex organic molecules in Sagittarius B2(N2)
• Complex Molecules in the L1157 Molecular Outflow
• Formation of complex organic molecules in hot molecular cores through nondiffusive grain-surface and ice-mantle chemistry
• Water in star-forming regions (WISH): Physics and chemistry from clouds to disks as probed by Herschel spectroscopy
• Low sulfur depletion in the Horsehead PDR
• Multilayer formation and evaporation of deuterated ices in prestellar and protostellar cores
• Seeds of Life in Space (SOLIS) III. Formamide in protostellar shocks: evidence for gas-phase formation
• Questioning the spatial origin of complex organic molecules in young protostars with the CALYPSO survey
• Astrochemical evolution along star formation: Overview of the IRAM Large Program ASAI
• CO outflows from high-mass Class 0 protostars in Cygnus-X
• L1157-B1, a factory of complex organic molecules in a Solar-type star forming region
• ALMA discovery of a rotating SO/SO${}_2$ flow in HH212. A possible MHD disk wind?
• The ALMA-PILS survey: Complex nitriles towards IRAS 16293--2422
• Luminosity Functions of Spitzer Identified Protostars in Nine Nearby Molecular Clouds
• The impact of shocks on the chemistry of molecular clouds: high resolution images of chemical differentiation along the NGC1333-IRAS2A outflow
• Orion KL: The hot core that is not a "Hot Core"
• The jet and the disk of the HH 212 low-mass protostar imaged by ALMA: SO and SO2 emission
• Water and methanol in low-mass protostellar outflows: gas-phase synthesis, ice sputtering and destruction
• Chemical stratification in the Orion Bar: JCMT Spectral Legacy Survey observations
• Deuterated molecules in Orion KL from Herschel/HIFI
• The complex chemistry of outflow cavity walls exposed: the case of low-mass protostars
• Modeling accretion shocks at the disk-envelope interface -- Sulfur chemistry
• The Dependence of Protostellar Luminosity on Environment in the Cygnus-X Star-Forming Complex
• Chemical segregation toward massive hot cores: The AFGL2591 star forming region
• The search for high-mass protostars with ALMA revealed up to kilo-parsec scales (SPARKS): I. Indication for a centrifugal barrier in the environment of a single high-mass envelope
• The ALMA-PILS survey: The first detection of doubly-deuterated methyl formate (CHD2OCHO) in the ISM
• Mass Assembly of Stellar Systems and Their Evolution with the SMA (MASSES). Multiplicity and the Physical Environment in L1448N
• Low levels of methanol deuteration in the high-mass star-forming region NGC 6334I
• Mass Assembly of Stellar Systems and their Evolution with the SMA - 1.3 mm Subcompact Data Release
• ALMA observations of doubly deuterated water: Inheritance of water from the prestellar environment
• Sulfur-Bearing Species Tracing the Disk/Envelope System in the Class I Protostellar Source Elias 29
• Chemistry of a newly detected circumbinary disk in Ophiuchus
• Protostellar Interferometric Line Survey of the Cygnus X region (PILS-Cygnus) -- First results: observations of CygX-N30
• Mass Assembly of Stellar Systems and their Evolution with the SMA (MASSES) -- Full Data Release
• ALMA observations of the archetypal "hot core" that isn't: Orion KL
• Disk fragmentation in high-mass star formation. High-resolution observations towards AFGL 2591-VLA 3
• Connecting Galactic and extragalactic outflows: From the Cygnus-X cluster to active galaxies
• Linking High- and Low-Mass Star Formation: Observation-Based Continuum Modelling and Physical Conditions
• Chemical compositions in the vicinity of protostars in Ophiuchus