A5024501534- Astrophysics and Star Formation Studies
- Stellar, planetary, and galactic studies
- Galaxies: Formation, Evolution, Phenomena
- Astrophysical Phenomena and Observations
- Astrophysics and Cosmic Phenomena
- Spectroscopy and Laser Applications
- Astronomy and Astrophysical Research
- Gamma-ray bursts and supernovae
- Atmospheric Ozone and Climate
- Molecular Spectroscopy and Structure
- Superconducting and THz Device Technology
- Atomic and Molecular Physics
- Radio Astronomy Observations and Technology
- Microwave Engineering and Waveguides
- Astro and Planetary Science
- Adaptive optics and wavefront sensing
- Chemical Synthesis and Analysis
- Chemical Synthesis and Reactions
- Phase Equilibria and Thermodynamics
- Astronomical Observations and Instrumentation
- Free Radicals and Antioxidants
- Lipid metabolism and biosynthesis
- Cardiac Imaging and Diagnostics
- Fullerene Chemistry and Applications
- Chalcogenide Semiconductor Thin Films
Keio University
2014-2024
Hiroshima City University
2005-2024
Hiroshima University
2017
High Energy Accelerator Research Organization
2014
The University of Tokyo
1997-2011
Misato Observatory
2008-2011
National Radio Astronomy Observatory
2010
National Astronomical Observatory of Japan
2009
Institute of Astronomy
2007-2008
Tokyo Institute of Technology
2007
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 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 present results of a 1.1-mm deep survey the AKARI Deep Field South (ADF-S) with AzTEC mounted on Atacama Submillimetre Telescope Experiment (ASTE). obtained map 0.25-deg2 area an rms noise level 0.32–0.71 mJy. This is one deepest and widest maps thus far at millimetre submillimetre wavelengths. uncovered 198 sources significance 3.5σ–15.6σ, providing largest catalogue in contiguous region. Most are not detected far-infrared bands satellite, suggesting that they mostly z≥ 1.5 given...
We present high-resolution CO J = 3–2 maps of the Galactic center region, taken with ASTE 10 m telescope. have collected approximately 30,000 spectra a 34'' grid spacing. The mapping area is roughly −18 < l +35 and −08 b +09, which includes central molecular zone Bania's Clump 2, covering almost full extent gas concentration in center. These images show behavior similar to 1–0 same resolution. Molecular shows higher 3–2/J intensity ratio (∼0.7) than spiral arms disk (∼0.4). 3–2/CO luminosity...
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...
Phosphorus (P) is a crucial element for life given its central role in several biomolecules. P-bearing molecules have been discovered different regions of the Milky Way, but not yet towards an extragalactic environment. We searched nearby starburst Galaxy NGC 253. Using observations from ALMA Comprehensive High-resolution Extragalactic Molecular Inventory (ALCHEMI) project, we used MADCUBA package to model emission assuming Local Thermodynamic Equilibrium (LTE) conditions. also performed...
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 surveyed the central molecular zone (CMZ) of our Galaxy in CO J=3-2 line with Atacama Submillimeter-wave Telescope Experiment (ASTE). Molecular gas Galactic center shows high J=3-2/J=1-0 intensity ratio (~ 0.9) while spiral arms disk lower 0.5). The high-velocity compact cloud 0.02-0.02 and hyperenergetic shell 1.27+0.01, as well Sgr A region exhibit exceeding 1.5. also found a number small spots gas. Some these large velocity widths some seem to associate nonthermal threads or...
We report the results of millimeter and submillimeter molecular line mapping observations Galactic circumnuclear disk (CND). The CND appears as a large, asymmetric warm gas with high CO J = 3–2/CO 1–0 intensity ratio exceeding 1.5. It has mass (2–5) × 105 M☉ diameter about 10 pc, including well-known 2-pc radius ring dense around minispiral. can be clearly traced by lines HCN, H13CN, HCO+, HNC, but it is barely N2H+, SiO, CCS, HC3N lines. These data confirm entity CND, just part it. Line...
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)...
Context: Methanol masers of Class I (collisionally-pumped) and II (radiatively-pumped) have been studied in great detail our Galaxy a variety astrophysical environments such as shocks star-forming regions are helpful to analyze the properties dense interstellar medium. However, study methanol external galaxies is still its infancy. Aims: Our main goal search for central molecular zone (CMZ; inner 500 pc) nearby starburst galaxy NGC 253. Methods: Covering frequency range between 84 373 GHz...
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...
ASTE is a 10-m submillimeter telescope operating in Atacama desert northern Chile since 2002 by NAOJ and collaborators. Thanks to the excellent observing condition at site, has been producing numerous astronomical results from star forming regions, Galactic center, Magellanic clouds, nearby galaxies, galaxy clusters. There three major improvements during years 2007-2008: continuum camera "AzTEC", new SIS receiver "CATS345", wide-band spectrometer "WHSF". AzTEC 144 element bolometer array 270...
We report the detection of an extremely bright ($\sim$37 mJy at 1100 $\mu$m and $\sim$91 880 $\mu$m) submillimeter galaxy (SMG), AzTEC-ASTE-SXDF1100.001 (hereafter referred to as SXDF1100.001 or Orochi), discovered in observations Subaru/XMM-Newton Deep Field using AzTEC on ASTE. Subsequent CARMA 1300 SMA successfully pinpoint location Orochi suggest that it has two components, one extended (FWHM $\sim$ 4$^{\prime\prime}$) compact (unresolved). Z-Spec CSO also been used obtain a wide band...
Abstract Molecular abundances are sensitive to the UV photon flux and cosmic-ray ionization rate. In starburst environments, effects of high-energy photons particles expected be stronger. We examine these astrochemical signatures through multiple transitions HCO + its metastable isomer HOC in center galaxy NGC 253 using data from Atacama Large Millimeter/submillimeter Array large program ALMA Comprehensive High-resolution Extragalactic inventory. The distribution (1−0) integrated intensity...
Abstract Molecular lines are powerful diagnostics of the physical and chemical properties interstellar medium (ISM). These ISM properties, which affect future star formation, expected to differ in starburst galaxies from those more quiescent galaxies. We investigate central molecular zone nearby galaxy NGC 253 using ultrawide millimeter spectral scan survey Atacama Large Millimeter/submillimeter Array Program ALCHEMI. present an atlas velocity-integrated images at a 1.″6 resolution 148...
Aims. The physical properties of galactic molecular outflows are important as they could constrain outflow formation mechanisms. In this work, we study the southwest (SW) streamer including gas kinematics, optical depth, dense fraction, and shock strength through emission in central zone starburst galaxy NGC 253. Methods. We imaged 253 at a spatial resolution 1.6″(∼27 pc D ∼ 3.5 Mpc) based on data from ALMA Comprehensive High-resolution Extragalactic Molecular Inventory (ALCHEMI) large...
Context. Sulphur-bearing species are detected in various environments within Galactic star-forming regions and particularly abundant the gas phase of outflow shocked addition to photo-dissociation regions. Thanks powerful capabilities millimetre interferometers, studying sulphur-bearing their region emission extreme extra-galactic (e.g. starburst active galactic nuclei) at a high-angular resolution sensitivity is now possible. Aims. In this work, we aim investigate nature from most common...
In order to precisely determine temperature and density of molecular gas in the Large Magellanic Cloud, we made observations optically thin $^{13}$CO($J=3-2$) transition by using ASTE 10m telescope toward 9 peaks where $^{12}$CO($J=3-2$) clumps were previously detected with same telescope. The include those giant cloud (GMC) Types I (with no signs massive star formation), II HII regions only), III young clusters). We emission all found that their intensities are 3 -- 12 times lower than...
We present $1''.4$ (98 pc) resolution ALMA observations of $^{13}$CO($J$=1-0), C$^{18}$O($J$=1-0), CS($J$=2-1) and CH$_3$OH($J_K$=$2_K$-$1_K$) molecular lines in the central $1'$ (4.2 kpc) region NGC 1068 to study physical chemical properties giant clouds (GMCs) test whether these GMC-scale are linked larger-scale galactic environment. Using derived $^{13}$CO cube, we have identified 187 high-significance ($> 8\sigma$) GMCs by employing CLUMPFIND algorithm. The gas masses $M_{\rm ^{13}CO}$,...
Abstract We present new 3 mm observations of the ionized gas toward nuclear starburst in nearby ( D ∼ 3.5 Mpc) galaxy NGC 253. With ALMA, we detect emission from H40 α and He40 lines central 200 pc this on spatial scales ∼4 pc. The recombination line primarily originates a population approximately dozen embedded super star clusters early stages formation. find that these is characterized by electron temperatures ranging 7000 to 10,000 K measures an average singly helium abundance 〈 Y + 〉 =...