A5057939394- Astrophysics and Star Formation Studies
- Galaxies: Formation, Evolution, Phenomena
- Stellar, planetary, and galactic studies
- Astronomy and Astrophysical Research
- Astrophysical Phenomena and Observations
- Spectroscopy and Laser Applications
- Atmospheric Ozone and Climate
- Molecular Spectroscopy and Structure
- Gamma-ray bursts and supernovae
- Astronomical Observations and Instrumentation
- Atomic and Molecular Physics
- Advanced Combustion Engine Technologies
- Astro and Planetary Science
- Astrophysics and Cosmic Phenomena
- Adaptive optics and wavefront sensing
- Pharmacological Effects and Assays
- Phase Equilibria and Thermodynamics
- Advanced Chemical Physics Studies
- Cardiac Imaging and Diagnostics
- Tribology and Lubrication Engineering
- Space Exploration and Technology
- Photocathodes and Microchannel Plates
- Thermodynamic properties of mixtures
- Methane Hydrates and Related Phenomena
- Calibration and Measurement Techniques
Institute of Astronomy and Astrophysics, Academia Sinica
2015-2024
National Astronomical Observatory of Japan
2021-2024
The Graduate University for Advanced Studies, SOKENDAI
2021-2024
Hiroshima University
2021
National Institutes of Natural Sciences
2021
Max Planck Institute for Radio Astronomy
2012-2016
Max Planck Society
2016
The Ohio State University
2008-2013
Chemical models used to study the chemical composition of gas and ices in interstellar medium are based on a network reactions associated rate coefficients. These coefficients partially compiled from data literature, when available. We present this paper kida.uva.2014, new updated version kida.uva public gas-phase first released 2012. In addition description many specific updates, we illustrate changes predicted abundances molecules for cold dense cloud conditions as compared with results...
We present a new interstellar chemical gas-phase reaction network for time-dependent kinetics that can be used modeling high-temperature sources up to ≈800 K. This contains an extended set of reactions based on the Ohio State University (OSU) network. The additional include processes with significant activation energies, reverse reactions, proton exchange charge and collisional dissociation. Rate coefficients already in OSU are modified H2 formation grains, ion–neutral dipole some radiative...
We used the Atacama Large Millimeter/submillimeter Array (ALMA), covering a nearly contiguous 289 GHz frequency range between 84.2 and 373.2 GHz, to image continuum spectral line emission at 1.6\arcsec ($\sim 28$ pc) resolution down sensitivity of $30-50$ mK. This article describes ALMA Comprehensive High-resolution Extragalactic Molecular Inventory (ALCHEMI) Program. focus on analysis spectra extracted from $15''$ ($\sim255$ Compact data. model molecular assuming local thermodynamic...
Abstract We present the first 100 pc scale view of dense molecular gas in central ∼1.3 kpc type-1 Seyfert NGC 1097, traced by HCN (J = 4–3) and HCO+ lines afforded with ALMA band 7. This galaxy shows significant enhancement respect to CO low-J transitions, which seems be a common characteristic AGN environments. Using data, we consider characteristics around this AGN, search for mechanism enhancement. find high line ratio nucleus. The upper limit brightness temperature (v 2 11f , J is 0.08,...
Carbon and oxygen isotope ratios are excellent measures of nuclear processing, but few such data have been taken toward extragalactic targets so far. Therefore, using the IRAM 30-m telescope, CN CO isotopologues measured nearby starburst galaxy NGC 253 prototypical ultraluminous infrared Mrk 231. Toward center 253, 13CN N = 1 → 0 lines indicate no significant deviations from expected local thermodynamical equilibrium after accounting for moderate saturation effects (10 25%) in two detected...
ABSTRACT Compiling data from literature and the Atacama Large Millimeter/submillimeter Array archive, we show enhanced HCN(4–3)/HCO + (4–3) and/or HCN(4–3)/CS(7–6) integrated intensity ratios in circumnuclear molecular gas around active galactic nuclei (AGNs) compared to those starburst (SB) galaxies (submillimeter HCN enhancement). The number of sample is significantly increased our previous work. We expect that this feature could potentially be an extinction-free energy diagnostic tool...
Abstract We present a spatially resolved excitation analysis for the central molecular zone (CMZ) of starburst galaxy NGC 253 using data from Atacama Large Millimeter/submillimeter Array Comprehensive High-resolution Extragalactic Molecular Inventory, whereby we explore parameters distinguishing quiescent Milky Way’s Galactic center (GC). Non-LTE analyses employing hierarchical Bayesian framework are applied to Band 3–7 transitions nine species delineate position–position–velocity...
We explore the potential of imaging vibrationally excited molecular emission at high angular resolution to better understand morphology and physical structure dense gas in Arp~220 gain insight into nature nuclear powering sources. Vibrationally HCN is detected both nuclei with a very ratio relative total $L_{FIR}$, higher than any other observed galaxy well above what Galactic hot cores. $v_2=1f$ be marginally resolved $\sim60\times50$~pc regions inside dusty $\sim100$~pc sized Its centered...
We used the Atacama Large Millimeter/submillimeter Array (ALMA) to map $^{12}$CO($J$ = 1-0), 2-1), 3-2), $^{13}$CO($J$ and [CI]($^3P_1$-$^3P_0$) emission lines around type 1 active galactic nucleus (AGN) of NGC 7469 ($z 0.0164$) at $\sim 100$ pc resolutions. The CO are bright both in circumnuclear disk (central 300$ pc) surrounding starburst (SB) ring ($\sim 1$ kpc diameter), with two peaks on either side AGN. By contrast, line is strongly peaked Consequently, brightness temperature ratio...
We analyze HCN and HNC emission in the nearby starburst galaxy NGC 253 to investigate its effectiveness tracing heating processes associated with star formation. This study uses multiple rotational transitions observed using ALMA via ALCHEMI Large Program. To understand conditions mechanisms within 253's dense gas, we employ Bayesian nested sampling techniques applied chemical radiative transfer models which are constrained our measurements. find that volume density $n_{\text{H}_{2}}$ cosmic...
Abstract We present Atacama Large Millimeter/submillimeter Array (ALMA) imaging of molecular gas across the full star-forming disk barred spiral galaxy M83 in CO( J = 1–0). jointly deconvolve data from ALMA’s 12 m, 7 and Total Power arrays using MIRIAD package. The have a mass sensitivity resolution 10 4 M ⊙ (3 σ ) 40 pc—sufficient to detect resolve typical cloud Milky Way with diameter × 5 pc, respectively. coverage shows that characteristics change radially center outer disk, locally...
Studying the interstellar medium in nearby starbursts is essential for understanding physical mechanisms driving these objects, thought to resemble young star-forming galaxies. This study aims analyze properties of first spatially-resolved multi-wavelength SED an extragalactic source, spanning six decades frequency (from near-UV cm wavelengths) at angular resolution 3$^{\prime\prime}$ (51 pc distance NGC,253). We focus on central molecular zone (CMZ) NGC,253, which contains giant clouds...
Understanding the chemistry of molecular clouds is pivotal to elucidate star formation and galaxy evolution. As one important ions, HCNH^+ plays an role in this chemistry. Yet, its behavior significance under extreme conditions, such as central zones (CMZs) external galaxies, are still largely unexplored. We aim reveal physical chemical properties CMZ starburst NGC 253 with multiple transitions shed light on molecule's conditions a starburst. employed line data including results for four...
We have investigated the role of molecular anion chemistry in pseudo-time-dependent chemical models dark clouds. With oxygen-rich elemental abundances, addition anions results a slight improvement overall agreement between model and observations abundances Taurus cloud 1 (TMC-1 (CP)). More importantly, with inclusion anions, we see an enhanced production efficiency unsaturated carbon-chain neutral molecules, especially longer members families CnH, CnH2, HCnN. The use carbon-rich TMC-1 (CP)...
We use a high-temperature chemical network to derive the molecular abundances in axisymmetric accretion disk models around active galactic nuclei (AGNs) within 100 pc using simple radial and vertical density temperature distributions motivated by more detailed physical models. explore effects of X-ray irradiation cosmic ray ionization on spatial distribution CO, CN, CS, HCN, HCO+, HC3N, C2H, c-C3H2 variety plausible structures. These have regions with layer dominated regions, midplane...
We present Atacama Large Millimeter/submillimeter Array (ALMA) Cycle 1 observations of the central kiloparsec region luminous type Seyfert galaxy NGC 7469 with unprecedented high resolution (05 ×04 = 165 × 132 pc) at submillimeter wavelengths. Utilizing wide bandwidth ALMA, we simultaneously obtained HCN(4–3), HCO+(4–3), CS(7–6), and partially CO(3–2) line maps, as well 860 μm continuum. The consists ∼1'' component surrounding starburst ring a radius ∼15–25. Several structures connect these...
Abstract In external galaxies, molecular composition may be influenced by extreme environments such as starbursts and galaxy mergers. To study chemistry, we observed the luminous infrared merger NGC 3256 using Atacama Large Millimeter/submillimeter Array. We covered most of 3 1.3 mm bands for a multispecies, multitransition analysis. first analyzed intensity ratio maps selected lines HCN/HCO + , which shows no enhancement at an active galactic nucleus. then compared chemical compositions...
We obtained an ALMA Cycle 0 spectral scan of the dusty LIRG NGC 4418, spanning a total 70.7 GHz in bands 3, 6, and 7. use combined local thermal equilibrium (LTE) non-LTE (NLTE) fit spectrum order to identify molecular species derive column densities excitation temperatures. abundances compare them with other Galactic extragalactic sources by means principal component analysis. detect 317 emission lines from 45 species, including 15 isotopic substitutions six vibrationally excited variants....
Observations of chemical species can provide an insight into the physical conditions emitting gas but it is important to understand how their abundances and excitation vary within different heating environments. C$_2$H a molecule typically found in PDR regions our own Galaxy there evidence suggest also traces other undergoing energetic processing extragalactic As part ALCHEMI ALMA large program, emission central molecular zone nearby starburst galaxy NGC 253 was mapped at 1.6 " (28 pc)...
The cosmic ray ionization rate (CRIR) is a key parameter in understanding the physical and chemical processes interstellar medium. Cosmic rays are significant source of energy star formation regions, which impacts drive stars. Previous studies circum-molecular zone (CMZ) starburst galaxy NGC 253 have found evidence for high CRIR value; $10^3-10^6$ times average within Milky Way. This broad constraint one goal this study to determine value with much higher precision. We exploit ALMA...
The low-mass protostellar region L1527 is unusual because it contains observable abundances of unsaturated carbon-chain molecules including CnH radicals, H2Cn carbenes, cyanopolyynes, and the negative ions C4H- C6H-, all which are more associated with cold cores than regions. Sakai et al. suggested that these formed in from chemical precursor methane, evaporates grains during heat-up region. With gas-phase osu.03.2008 network extended to include families Cn-, CnH-, as well newly detected...
We report observations of the reactive molecular ions OH$^+$, H$_2$O$^+$, and H$_3$O$^+$ towards Orion KL with Herschel/HIFI. All three $N=1-0$ fine-structure transitions OH$^+$ at 909, 971, 1033GHz both components doublet {\it ortho}-H$_2$O$^+$ $1_{11}-0_{00}$ transition 1115 1139GHz were detected; an upper limit was obtained for H$_3$O$^+$. H$_2$O$^+$ are observed purely in absorption, showing a narrow component source velocity 9 kms$^{-1}$, broad blueshifted absorption similar to that...
Abstract We present 0.8-mm band molecular images and spectra obtained with the Atacama Large Millimeter/submillimeter Array (ALMA) toward one of nearest galaxies an active galactic nucleus (AGN), NGC 1068. Distributions CO isotopic species (13CO C18O) J = 3–2, CN N CS 7–6 are observed circumnuclear disk (CND) a part starburst ring angular resolution ∼ 1${^{\prime\prime}_{.}}$3 × 1${^{\prime\prime}_{.}}$2. The physical properties these molecules shock-related molecules, such as HNCO, CH3CN,...
In order to study a molecular-cloud-scale chemical composition, we have conducted mapping spectral line survey toward the Galactic molecular cloud W3(OH), which is one of most active star forming regions in Perseus arm, with NRO 45 m telescope. We observed area 16' $\times$ 16', corresponds 9.0 pc pc. The frequency ranges are 87--91, 96--103, and 108--112 GHz. prepared spectrum averaged over area, 8 species CCH, HCN, HCO$^+$, HNC, CS, SO, C$^{18}$O, $^{13}$CO identified. On other hand,...
Aims. The circumnuclear disk (CND) of the Galactic center is exposed to many energetic phenomena coming from supermassive black hole Sgr A* and stellar activities. These activities can affect chemical composition in CND through interaction with UV photons, cosmic rays, X-rays, shock waves. We aim constrain physical conditions present modeling observed molecular species detected toward it.