Vibrationally excited HC3N emission in NGC1068: Tracing the recent star formation in the starburst ring

Abstract

Using ALMA data, we have studied the HC${}_3$N and continuum emission in the starburst ring (SB ring) and the circumnuclear disc (CND) of the SB/AGN composite galaxy NGC 1068. We have detected emission from vibrationally excited HC${}_3$N (HC${}_3$N*) only towards one star-forming region of the SB ring. Remarkably, HC${}_3$N* was not detected towards the CND despite its large HC${}_3$N $v=0$ column density. From LTE and non-LTE modelling of HC${}_3$N*, we obtained a dust temperature of $T_{\text{dust}}\sim 250$ K and a density of $n_{{\text{H}}_2}=6\times 10^5$ cm${}^{-3}$ for this star-forming region. The estimated IR luminosity of $5.8\times 10^8$ L${}_{\odot }$ is typical of proto-Super Star Clusters (proto-SSC) observed in the SB galaxy NGC 253. We use the continuum emissions at $147$ GHz and $350$ GHz, along with CO and Pa $\alpha$, to estimate the ages of other $14$ SSCs in the SB ring. We find the youngest SSCs to be associated with the region connecting the nuclear bar with the SB ring, supporting the scenario of sequential star formation. For the CND, our analysis yields $T_{\text{dust}}⩽100$ K and $n_{{\text{H}}_2}\sim (3-6)\times 10^5$cm${}^{-3}$. The very different dust temperatures found for the CND and the proto-SSC indicates that, while the dust in the proto-SSC is being efficiently heated from the inside by the radiation from massive proto-stars, the CND is being heated externally by the AGN, which in the IR optically thin case can only heat the dust to $56$ K. We discuss the implications of the non-detection of HC${}_3$N* near the luminous AGN in NGC 1068 on the interpretation of the HC${}_3$N* emission observed in the SB/AGN composite galaxies NGC 4418 and Arp 220.

arXiv commentsubmitted to MNRAS on 08/08/2020

References in corpus (58)

• Star Formation in Galaxies Along the Hubble Sequence
• What Powers Ultra-luminous IRAS Galaxies?
• Calibrating Extinction-Free Star Formation Rate Diagnostics with 33GHz Free-Free Emission in NGC6946
• Molecular line emission in NGC1068 imaged with ALMA. I An AGN-driven outflow in the dense molecular gas
• A Close Look at Star Formation around Active Galactic Nuclei
• Evolution of Massive Protostars with High Accretion Rates
• Bars and Warps traced by the Molecular Gas in the Seyfert 2 Galaxy NGC 1068
• Torus and AGN properties of nearby Seyfert galaxies: Results from fitting IR spectral energy distributions and spectroscopy
• Counterrotating Nuclear Disks in Arp 220
• ALMA observations of molecular tori around massive black holes
• Molecular Gas Chemistry in AGN I. The IRAM Survey of NGC1068
• Luminous Infrared Galaxies with the Submillimeter Array: I. Survey Overview and the Central Gas to Dust Ratio
• Herschel/PACS spectroscopy of NGC 4418 and Arp 220: H2O, H2^{18}O, OH, ^{18}OH, O I, HCN and NH3
• Molecular line emission in NGC1068 imaged with ALMA: II. The chemistry of the dense molecular gas
• ALMA images the many faces of the NGC1068 torus and its surroundings
• The Obscured Fraction of AGN in the XMM-COSMOS Survey: A Spectral Energy Distribution Perspective
• Spectral Line Identification and Modelling (SLIM) in the MAdrid Data CUBe Analysis (MADCUBA) package: An interactive software for data cube analysis
• Vibrationally Excited HCN in the Luminous Infrared Galaxy NGC 4418
• SMA/PdBI multiple line observations of the nearby Seyfert2 galaxy NGC 1068: Shock related gas kinematics and heating in the central 100pc?
• A SINFONI view of Galaxy Centers: Morphology and Kinematics of five Nuclear Star Formation Rings
• Forming Super Star Clusters in the Central Starburst of NGC 253
• Submillimetre line spectrum of the Seyfert galaxy NGC1068 from the Herschel-SPIRE Fourier Transform Spectrometer
• Molecular gas chemistry in AGN. II. High-resolution imaging of SiO emission in NGC1068: shocks or XDR?
• The Submillimeter Array 1.3 mm line survey of Arp 220
• Submillimeter Interferometry of the Luminous Infrared Galaxy NGC 4418: A Hidden Hot Nucleus with an Inflow and an Outflow
• High-Resolution Radio Continuum Measurements of the Nuclear Disks of Arp 220
• Herschel-PACS Observations of Far-IR CO Line Emission in NGC 1068: Highly Excited Molecular Gas in the Circumnuclear Disk
• A lambda=3 mm molecular line survey of NGC1068. Chemical signatures of an AGN environment
• Surviving the hole I: Spatially resolved chemistry around Sgr A*
• The Stellar Kinematic Center and the True Galactic Nucleus of NGC253
• Extreme dust disks in Arp 220 as revealed by ALMA
• Exploring the molecular chemistry and excitation in obscured luminous infrared galaxies: An ALMA mm-wave spectral scan of NGC 4418
• ALMA 0.1-0.2 arcsec resolution imaging of the NGC 1068 nucleus - compact dense molecular gas emission at the putative AGN location
• Modeling the H2O submillimeter emission in extragalactic sources
• The Black Hole Mass Function Derived from Local Spiral Galaxies
• The unbearable opaqueness of Arp 220
• A high-resolution mm and cm study of the obscured LIRG NGC 4418 - A compact obscured nucleus fed by in-falling gas?
• Vibrationally excited HC3N in NGC 4418
• Super Hot Cores in NGC 253: Witnessing the formation and early evolution of Super Star Clusters
• Galactic Bar/Spiral Arm Interactions in NGC3627
• ALMA imaging of C2H emission in the disk of NGC1068
• Resolved Structure of Arp 220 Nuclei at λ~3 mm
• A new intermediate mass protostar in the Cepheus A HW2 region
• Molecular shock tracers in NGC 1068: SiO and HNCO
• ALMA Spatially-resolved Dense Molecular Gas Survey of Nearby Ultraluminous Infrared Galaxies
• The Initial Cluster Mass Function of Super Star Clusters in Irregular and Spiral Galaxies
• The radio core structure of the luminous infrared galaxy NGC 4418
• The Greenhouse Effect in Buried Galactic Nuclei and the Resonant HCN Vibrational Emission
• Geometric Offsets Across Spiral Arms in M51: Nature of Gas and Star Formation Tracers
• VLT-SINFONI sub-kpc study of the star formation in local LIRGs and ULIRGs: Analysis of the global ${\Sigma }_{\mathrm{SFR}}$ structure and characterisation of individual star-forming clumps
• Continuum emission in NGC1068 and NGC3147: Indications for a turnover in the core spectra
• Unveiling the main heating sources in the Cepheus A HW2 region
• Discovery and Rapid Follow-up Observations of the Unusual Type II SN 2018ivc in NGC 1068
• Near-IR 2D-Spectroscopy of the 4''x 4'' region around the Active Galactic Nucleus of NGC1068 with ISAAC/VLT
• On the heating of source of the Orion KL hot core
• The excitation of near-infrared H2 emission in NGC 253
• The Youngest Globular Clusters
• Chemical complexity in NGC1068

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