ALMA observations of massive clouds in the central molecular zone: slim filaments tracing parsec-scale shocks

Abstract

The central molecular zone (CMZ) of our Galaxy exhibits widespread emission from SiO and various complex organic molecules (COMs), yet the exact origin of such emission is uncertain. Here we report the discovery of a unique class of long ($>$0.5 pc) and narrow ($<$0.03 pc) filaments in the emission of SiO 5$-$4 and eight additional molecular lines, including several COMs, in our ALMA 1.3 mm spectral line observations toward two massive molecular clouds in the CMZ, which we name as slim filaments. However, these filaments are not detected in the 1.3 mm continuum at the 5$\sigma$ level. Their line-of-sight velocities are coherent and inconsistent with being outflows. The column densities and relative abundances of the detected molecules are statistically similar to those in protostellar outflows but different from those in dense cores within the same clouds. Turbulent pressure in these filaments dominates over self gravity and leads to hydrostatic inequilibrium, indicating that they are a different class of objects than the dense gas filaments in dynamical equilibrium ubiquitously found in nearby molecular clouds. We argue that these newly detected slim filaments are associated with parsec-scale shocks, likely arising from dynamic interactions between shock waves and molecular clouds. The dissipation of the slim filaments may replenish SiO and COMs in the interstellar medium and lead to their widespread emission in the CMZ.

arXiv comment14 pages, 9 figures, 2 tables

References in corpus (63)

• Astropy: A Community Python Package for Astronomy
• An atomic and molecular database for analysis of submillimetre line observations
• CASA, the Common Astronomy Software Applications for Radio Astronomy
• The Cologne Database for Molecular Spectroscopy, CDMS, in the Virtual Atomic and Molecular Data Centre, VAMDC
• Characterizing interstellar filaments with Herschel in IC5146
• Trigonometric Parallaxes Of High-Mass Star Forming Regions: Our View Of The Milky Way
• MAMBO Mapping of Spitzer c2d Small Clouds and Cores
• The Critical Density and the Effective Excitation Density of Commonly Observed Molecular Dense Gas Tracers
• How to Calculate Molecular Column Density
• Variations in the Galactic star formation rate and density thresholds for star formation
• The earliest phases of high-mass star formation: a 3 square degree millimeter continuum mapping of Cygnus X
• What controls star formation in the central 500 pc of the Galaxy?
• Hierarchical fragmentation and differential star formation in the Galactic "Snake": infrared dark cloud G11.11-0.12
• Dense gas in the Galactic central molecular zone is warm and heated by turbulence
• An ALMA study of the Orion Integral Filament: I. Evidence for narrow fibers in a massive cloud
• Molecular gas kinematics within the central 250 pc of the Milky Way
• The largest oxigen bearing organic molecule repository
• Spatial distribution of interstellar gas in the innermost 3 kpc of our Galaxy
• Characterizing the properties of nearby molecular filaments observed with Herschel
• Star formation rates and efficiencies in the Galactic Centre
• The Post-Shock Chemical Lifetimes of Outflow Tracers and a Possible New Mechanism to Produce Water Ice Mantles
• SiO emission from the Galactic Center Molecular Clouds
• The thermal state of molecular clouds in the Galactic Center: evidence for non-photon-driven heating
• Parsec-scale SiO Emission in an Infrared Dark Cloud
• The 1.28 GHz MeerKAT Galactic Center Mosaic
• The Galactic Center Molecular Cloud Survey. I. A Steep Linewidth-Size Relation & Suppression of Star Formation
• Filamentary Fragmentation and Accretion in High-Mass Star-Forming Molecular Clouds
• Low-velocity shocks traced by extended SiO emission along the W43 ridges: witnessing the formation of young massive clusters
• Southern class I methanol masers at 36 and 44 GHz
• The Episodic, Precessing Giant Molecular Outflow from IRAS 04239+2436 (HH 300)
• ATLASGAL-selected massive clumps in the inner Galaxy, II: Characterisation of different evolutionary stages and their SiO emission
• The Survey of Water and Ammonia in the Galactic Center (SWAG): Molecular Cloud Evolution in the Central Molecular Zone
• The dynamical evolution of molecular clouds near the Galactic Centre - II. Spatial structure and kinematics of simulated clouds
• Gravitational fragmentation caught in the act: the filamentary Musca molecular cloud
• Detection of Widespread Hot Ammonia in the Galactic Center
• SiO outflows in high-mass star forming regions: A potential chemical clock?
• Gas Kinematics and Excitation in the Filamentary IRDC G035.39-00.33
• SiO emission from low- and high-velocity shocks in Cygnus-X massive dense clumps
• Widespread Methanol Emission from the Galactic Center
• Classification of Filament Formation Mechanisms in Magnetized Molecular Clouds
• Tracing extended low-velocity shocks through SiO emission - Case study of the W43-MM1 ridge
• Star Formation Rates of Massive Molecular Clouds in the Central Molecular Zone
• ALMA Observations of Massive Clouds in the Central Molecular Zone: Jeans Fragmentation and Cluster Formation
• Large scale grain mantle disruption in the Galactic Center
• A Census of Early Phase High-Mass Star Formation in the Central Molecular Zone
• ISM Processing in the Inner 20 pc in Galactic center
• High Resolution Imaging of Molecular Outflows in Massive Young Stars
• The Molecular Gas Environment in the 20 km s${}^{-1}$ Cloud in the Central Molecular Zone
• On the typical width of Herschel filaments
• ALMA Observations of Massive Clouds in the Central Molecular Zone: Ubiquitous Protostellar Outflows
• Expanded Very Large Array Detection of 44.1 GHz Class I Methanol Masers in Sagittarius A
• Temperature structures in Galactic Center clouds - Direct evidence for gas heating via turbulence
• Molecules in G1.6-0.025 - 'Hot' Chemistry in the Absence of Star Formation at the Periphery of the Galactic Center Region
• Interstellar Plunging Waves: ALMA resolves the physical structure of non-stationary MHD shocks
• Assessing the Performance of Molecular Gas Clump Identification Algorithms
• A train of shocks at 3000 au scale? Exploring the clash of an expanding bubble into the NGC 1333 IRAS 4 region. SOLIS XIV
• SOFIA/HAWC+ Far-Infrared Polarimetric Large-Area CMZ Exploration (FIREPLACE) Survey III: Full Survey Data Set
• Absorption Filaments Towards the Massive Clump G0.253+0.016
• A Large--Scale Spectroscopic Survey of Methanol and OH Line Emission from the Galactic Center: Observations and Data
• A wind-blown bubble in the Central Molecular Zone cloud G0.253+0.016
• ALMA uncovers highly filamentary structure towards the Sgr E region
• OMC-2 FIR 4 under the microscope: Shocks, filaments, and a highly collimated jet at 100 au scales
• Surveys of clumps, cores, and condensations in Cygnus-X: SMA observations of SiO (5$-$4)

Cited by in corpus (1)

• Chemical templates of the Central Molecular Zone. Shock and protostellar object signatures under Galactic Center conditions