SiO emission from the Galactic Center Molecular Clouds

Abstract

We have mapped the J=1-0 line of SiO in a 1 degree x 12 arcmin. (lxb) region around the Galactic center (GC) with an angular resolution of 2 arcmin. (approx. 4 pc). In contrast to the spatial distribution of other high dipole moment molecules like CS, whose emission is nearly uniform, the SiO emission is very fragmented and it is only associated with some molecular clouds. In particular, it is remarkable that the SiO emission closely follows the non-thermal radio arc in the GC. The SiO clouds are more extended than the beam with typical sizes between 4 and 20 pc. High angular resolution (26 arcsec.) mapping in the J=1-0 line of SiO toward the molecular clouds in Sgr B2 and Sgr A shows that the SiO emission is relatively smooth with structures of typically 2 pc. From the line intensities of the J=1-0, J=3-2 and J=5-4 transitions of SiO we derive H2 densities for these clouds of a few 1e4 cm-3. The SiO fractional abundances are approx. 1e-9 for the SiO clouds and 1e-10 for the other molecular clouds in the GC. The characteristics (size and H2 densities) of the SiO emission in the GC are completely different from those observed in the Galactic disk, where the SiO emission arises from much smaller regions with larger H2 densities. We briefly discuss the implications of the SiO emission in the molecular clouds of the GC. We conclude that the particular chemistry in these clouds is probably related to large scale fast shocks occurring in the Galactic center region.

9 pages, 4 Postscript figures, To be published in ApJ letters

Cited by in corpus (108)

• A 2 mm spectral line survey of the starburst galaxy NGC 253
• The largest oxigen bearing organic molecule repository
• Spectral imaging of the Central Molecular Zone in multiple 3-mm molecular lines
• Hot corinos in NGC1333-IRAS4B and IRAS2A
• 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
• Complex organic molecules in the Galactic Centre: the N-bearing family
• Tracing shocks and photodissociation in the Galactic center region
• The Galactic Center Molecular Cloud Survey. I. A Steep Linewidth-Size Relation & Suppression of Star Formation
• Dense gas in nearby galaxies XVI. The nuclear starburst environment in NGC4945
• Wild at Heart:-The Particle Astrophysics of the Galactic Centre
• The far-IR spectrum of Sagittarius B2 region: Extended molecular absorption, photodissociation and photoionization
• Low-velocity shocks traced by extended SiO emission along the W43 ridges: witnessing the formation of young massive clusters
• The Herschel view of massive star formation in G035.39--00.33: Dense and cold filament of W48 undergoing a mini-starburst
• Lambda = 3 mm line survey of nearby active galaxies
• Molecular gas chemistry in AGN. II. High-resolution imaging of SiO emission in NGC1068: shocks or XDR?
• HNCO enhancement by shocks in the L1157 molecular outflow
• Sulfur chemistry and isotopic ratios in the starburst galaxy NGC 253
• ISO observations of the Galactic center Interstellar Medium: neutral gas and dust
• Cloud-cloud collision as drivers of the chemical complexity in Galactic Centre molecular clouds
• Multi-molecule ALMA observations towards the Seyfert 1 galaxy NGC 1097
• ALCHEMI: an ALMA Comprehensive High-resolution Extragalactic Molecular Inventory. Survey presentation and first results from the ACA array
• SiO chimneys and supershells in M82
• Warm H2 in the Galactic center region
• Phosphorus-bearing molecules in the Galactic Center
• The Origin of X-ray Emission from a Galactic Center Molecular Cloud: Low Energy Cosmic Ray Electrons
• Surviving the hole I: Spatially resolved chemistry around Sgr A*
• Detection of Widespread Hot Ammonia in the Galactic Center
• Spectral imaging of the Sagittarius B2 region in multiple 3-mm molecular lines with the Mopra telescope
• Cosmic-Ray Heating of Molecular Gas in the Nuclear Disk: Low Star Formation Efficiency
• First detections of extragalactic SO2, NS and NO
• A CO J=3-2 Survey of the Galactic Center
• Herschel observations of the Sgr B2 cores: Hydrides, warm CO, and cold dust
• The dynamics and star-forming potential of the massive Galactic centre cloud G0.253+0.016
• Far-Infrared Spectroscopy of the Galactic Center. Hot Molecular Gas: Shocks versus Radiation near SgrA*
• Formation of silicon oxide grains at low temperature
• Widespread Methanol Emission from the Galactic Center
• 86 GHz SiO maser survey of late-type stars in the Inner Galaxy. I. Observational data
• Chemical Features in the Circumnuclear Disk of the Galactic Center
• CS, HC3N and CH3CCH multi-line analyses towards starburst galaxies. The evolution of cloud structures in the central regions of galaxies
• Abundant Methanol Masers but no New Evidence for Star Formation in GCM0.253+0.016
• A survey of the Galactic center region in HCO+, H13CO+ and SiO
• Large scale grain mantle disruption in the Galactic Center
• The Galactic Center Molecular Cloud Survey. II. A Lack of Dense Gas & Cloud Evolution along Galactic Center Orbits
• Large-scale molecular shocks in galaxies: the SiO interferometer map of IC342
• Coupling the dynamics and the molecular chemistry in the Galactic center
• Water Vapor around Sgr B2
• Early stage massive star formation near the Galactic Center: Sgr C
• Misaligned streamers around a galactic centre black hole from a single cloud's infall
• The Molecular Gas Environment in the 20 km s${}^{-1}$ Cloud in the Central Molecular Zone
• Mapping photodissociation and shocks in the vicinity of Sgr A*
• Thermal SiO and H${}^{13}$CO${}^{+}$ Line Observations of the Dense Molecular Cloud G0.11$-$0.11 in the Galactic Center region
• Molecular shock tracers in NGC 1068: SiO and HNCO
• Star formation in 'the Brick': ALMA reveals an active proto-cluster in the Galactic centre cloud G0.253+0.016
• A SiO J = 5 - 4 Survey Toward Massive Star Formation Regions
• 3 mm spectral line survey of two lines of sight toward two typical cloud complexes in the Galactic Center
• ALMA Observations of Massive Clouds in the Central Molecular Zone: Ubiquitous Protostellar Outflows
• Molecules in G1.6-0.025 - 'Hot' Chemistry in the Absence of Star Formation at the Periphery of the Galactic Center Region
• Origins of Scatter in the Relationship Between HCN 1-0 and Dense Gas Mass in the Galactic Center
• Spectral imaging of the Sagittarius B2 region in multiple 7-mm molecular lines
• HCN $J$=4-3, HNC $J$=1-0, ${\mathrm{H}}^{13}\mathrm{CN}$ $J$=1-0, and $\mathrm{H}{\mathrm{C}}_3\mathrm{N}$ $J$=10-9 Maps of Galactic Center Region I: Spatially-Resolved Measurements of Physical Conditions and Chemical Composition
• Structure and kinematics of shocked gas in Sgr B2: further evidence of a cloud-cloud collision from SiO emission maps
• ISO observations of the Galactic center Interstellar Medium: ionized gas
• 74 MHz Nonthermal Emission from Molecular Clouds: Evidence for a Cosmic Ray Dominated Region at the Galactic Center
• Shocked ammonia in the WR nebula NGC 2359
• A Molecular Line Survey toward the Nearby Galaxies NGC 1068, NGC 253, and IC 342 at 3 mm with the Nobeyama 45-m Radio Telescope: Impact of an AGN on 1 kpc Scale Molecular Abundances
• Sgr B2(N): A bipolar outflow and rotating hot core revealed by ALMA
• The Mid-Infrared Colors of the ISM and Extended Sources at the Galactic Center
• The first detection of SiC${}_2$ in the interstellar medium
• Insights into the Carbon chemistry of Mon R2
• Kinetic temperatures toward X1/X2 orbit interceptions regions and Giant Molecular Loops in the Galactic center region
• The chemical footprint of AGN feedback in the outflowing circumnuclear disk of NGC 1068
• Shocking Sgr B2(N1) with its own outflow: A new perspective on segregation between O- and N-bearing molecules
• Odin observations of the Galactic centre in the 118-GHz band. Upper limit to the O2 abundance
• A study of methanol and silicon monoxide production through episodic explosions of grain mantles in the Central Molecular Zone
• A 6.7 GHz methanol maser survey of the central molecular zone
• Reconstructing the shock history in the CMZ of NGC 253 with ALCHEMI
• X-ray emission from the giant molecular clouds in the Galactic Center region and the discovery of new X-ray sources
• High Velocity Compact Clouds in the Sagittarius C Region
• The diffuse molecular component in the nuclear bulge of the Milky Way
• HOCO+ toward the Galactic Center
• Conformational isomerism of methyl formate: new detections of the higher-energy trans conformer and theoretical insights
• Extended HNCO, SiO, and HC${}_3$N emission in 43 southern star-forming regions
• The molecular ISM in luminous infrared galaxies: a 3mm line survey of Arp 157
• An energetic high-velocity compact cloud: CO$-$0.31+0.11
• Processing of hydroxylamine, NH2OH, an important prebiotic precursor, on interstellar ices
• NH3 in the Galactic Center is formed in Cool Conditions
• The foot points of the Giant Molecular Loops in the Galactic center region
• Living on the edge of the Central Molecular Zone: G1.3 is the more likely candidate for gas accretion into the CMZ
• History-independent tracers: Forgetful molecular probes of the physical conditions of the dense interstellar medium
• Star Formation in Extreme Environments: A 200 pc High Velocity Gas Stream in the Galactic Centre
• Shaken or stirred: the diffuse interstellar medium with exceptionally high SiO abundance
• The LLAGN in the centre of the Galaxy
• New Look at the Molecular Superbubble Candidate in the Galactic Center
• Small-scale structure traced by neutral hydrogen absorption in the direction of multiple-component radio continuum sources
• A Multiwavelength Study of the Sgr B Region: Contiguous Cloud-Cloud Collisions Triggering Widespread Star Formation Events?
• Tracing the chemical footprint of shocks in AGN-host and starburst galaxies with ALMA multi-line molecular studies
• ALMA observations of massive clouds in the central molecular zone: slim filaments tracing parsec-scale shocks
• A Molecular Line Investigation of the Interaction between Mid-infrared Bubbles and the Interstellar Medium
• Chemical templates of the Central Molecular Zone. Shock and protostellar object signatures under Galactic Center conditions
• Herschel water maps towards the vicinity of the black hole Sgr A*
• Extragalactic chemistry of molecular gas: lessons from the local universe
• Star Formation in the Galactic Center
• Shock Structure and Shock Heating in the Galactic Central Molecular Zone
• Parabolic-like Trend in SiO Ratios throughout the Central Molecular Zone: Possible Signature of a Past Nuclear Activity in the Galactic Center
• The Chemistry and Kinematics of Two Molecular Clouds near Sagittarius A*
• Chemistry of Dark Molecular Clouds
• The Cygnus Allscale Survey of Chemistry and Dynamical Environments: CASCADE III. The large scale distribution of DCO+, DNC and DCN in the DR21 filament