Hideki Umehata
A5064135447- Galaxies: Formation, Evolution, Phenomena
- Astronomy and Astrophysical Research
- Astrophysics and Star Formation Studies
- Stellar, planetary, and galactic studies
- Astrophysical Phenomena and Observations
- Gamma-ray bursts and supernovae
- Astrophysics and Cosmic Phenomena
- Radio Astronomy Observations and Technology
- Astronomical Observations and Instrumentation
- Spectroscopy and Laser Applications
- Scientific Research and Discoveries
- Molecular Spectroscopy and Structure
- CCD and CMOS Imaging Sensors
- Adaptive optics and wavefront sensing
- Photocathodes and Microchannel Plates
- Astro and Planetary Science
- Black Holes and Theoretical Physics
- Superconducting and THz Device Technology
- Cosmology and Gravitation Theories
- Ionosphere and magnetosphere dynamics
- Plant Water Relations and Carbon Dynamics
- Radiation Effects in Electronics
- Pulsars and Gravitational Waves Research
- Phase Equilibria and Thermodynamics
- Atmospheric aerosols and clouds
Nagoya University
2022-2025
California Institute of Technology
2023-2024
The University of Tokyo
2014-2023
Pioneer (Japan)
2018-2021
RIKEN
2018-2021
The Open University of Japan
2017-2020
European Southern Observatory
2015-2017
National Astronomical Observatory of Japan
2012-2017
Institute of Astronomy
2012
The physical properties and elemental abundances of the interstellar medium in galaxies during cosmic reionization are important for understanding role this process. We report Atacama Large Millimeter/submillimeter Array detection an oxygen emission line at a wavelength 88 micrometers from galaxy epoch about 700 million years after Big Bang. abundance is estimated one-tenth that Sun. nondetection far-infrared continuum indicates deficiency dust galaxy. A carbon 158 also not detected,...
We report the source size distribution, as measured by ALMA millimetric continuum imaging, of a sample 13 AzTEC-selected submillimeter galaxies (SMGs) at –6. Their infrared luminosities and star formation rates (SFRs) are 2– ∼200–600 yr−1, respectively. The sizes these SMGs range from 010 to 038, with median 020 (FWHM), corresponding circularized effective radius () kpc, comparable typical stellar component in compact quiescent (cQGs)— kpc. surface SFR density our is yr−1 kpc−2, that seen...
We report on the detection of [CII] 157.7 $\mu$m emission from Lyman break galaxy (LBG) MACS0416_Y1 at z = 8.3113, by using Atacama Large Millimeter/submillimeter Array (ALMA). The luminosity ratio [OIII] 88 (from previous campaigns) to is 9.31 $\pm$ 2.6, indicative hard interstellar radiation fields and/or a low covering fraction photo-dissociation regions. cospatial 850 dust (90 rest-frame, campaigns), however peak does not agree with emission, suggesting that lines originate different...
We report the results of 15 × 3' mapping at 1.1 mm with Atacama Large Millimeter/submillimeter Array toward central region z = 3.09 SSA22 protocluster. By combining our source catalog archival spectroscopic redshifts, we find that eight submillimeter galaxies (SMGs) flux densities, S1.1 0.7–6.4 mJy (LIR ∼ 1012.1–1013.1 L⊙) are 3.08–3.10. Not only these SMGs members protocluster, but they in fact reside within node junction 50 Mpc scale filamentary three-dimensional structure traced by Lyα...
We have obtained three-dimensional maps of the universe in $\sim200\times200\times80$ comoving Mpc$^3$ (cMpc$^3$) volumes each at $z=5.7$ and $6.6$ based on a spectroscopic sample 179 galaxies that achieves $\gtrsim80$\% completeness down to Ly$\alpha$ luminosity $\log(L_{\rm Ly\alpha}/[\mathrm{erg\ s^{-1}}])=43.0$, our Keck Gemini observations literature. The reveal filamentary large-scale structures two remarkable overdensities made out least 44 12 $z=5.692$ (z57OD) $z=6.585$ (z66OD),...
Abstract We present the Atacama Large Millimeter/submillimeter Array detection of [O iii ] 88 μ m line and rest-frame 90 dust continuum emission in a Y -dropout Lyman break galaxy (LBG), MACS0416_Y1 lying behind Frontier Field cluster MACS J0416.1−2403. This confirms LBG with spectroscopic redshift z = 8.3118 ± 0.0003, making this object one farthest galaxies ever identified spectroscopically. The observed 850 flux density 137 26 Jy corresponds to de-lensed total infrared (IR) luminosity...
Abstract We present ALMA [C ii] line and far-infrared (FIR) continuum observations of three $z \gt 6$ low-luminosity quasars ($M_{\rm 1450} -25$ mag) discovered by our Subaru Hyper Suprime-Cam (HSC) survey. The was detected in all targets with luminosities $(2.4\mbox{--}9.5) \times 10^8\, L_{\odot }$, about one order magnitude smaller than optically luminous \lesssim quasars. FIR range from $\lt 9 10^{10}\, }$ (3 $\sigma$ limit) to ${\sim } 2 10^{12}\, indicating a wide star formation rates...
Abstract We present new ALMA observations and physical properties of a Lyman break galaxy at z = 7.15. Our target, B14-65666, has bright ultra-violet (UV) absolute magnitude, MUV ≈ −22.4, been spectroscopically identified in Lyα with small rest-frame equivalent width ≈4 Å. A previous Hubble Space TElescope (HST) image shown that the target is composed two spatially separated clumps UV. With ALMA, we have newly detected resolved [O iii] 88 μm, [C ii] 158 their underlying dust continuum...
We present an ALMA study of the ~180 brightest sources in SCUBA-2 map COSMOS field from S2COSMOS survey, as a pilot for AS2COSMOS - full survey ~1,000 this field. In we have obtained 870-um continuum maps essentially complete sample 182 sub-millimetre (S_850um=6.2mJy) COSMOS. Our detect 260 galaxies (SMGs) spanning range flux density S_870um=0.7-19.2mJy. more than one SMG counterpart 34+/-2 per cent sources, increasing to 53+/-8 brighter S_850um>12mJy. estimate that approximately one-third...
We present ALMA [CII] 158 $\mu$m line and underlying far-infrared (FIR) continuum emission observations ($0''.70 \times 0''.56$ resolution) toward HSC J124353.93$+$010038.5 (J1243$+$0100) at $z = 7.07$, the only low-luminosity ($M_{\rm 1450} > -25$ mag) quasar currently known 7$. The FIR is bright (1.52 mJy) resolved with a total luminosity of $L_{\rm FIR} 3.5 10^{12}~L_\odot$. spatially extended component responsible for $\sim 40\%$ emission. area-integrated spectrum shows broad wing (${\rm...
We present a set of multi-wavelength mosaics and photometric catalogs in the ALMA lensing cluster survey (ALCS) fields. The were built by reprocessing archival data from CHArGE compilation, taken $\textit{Hubble Space Telescope}$ ($\textit{HST}$) RELICS, CLASH Hubble Frontier Fields. Additionally we have reconstructed $\textit{Spitzer}$ IRAC 3.6 4.5 $\mu$m mosaics, utilising all available IRSA/SHA exposures. To alleviate effect blending such crowded region, modelled photometry convolving...
Abstract The mean free path of ionizing photons, λ mfp , is a critical parameter for modeling the intergalactic medium (IGM) both during and after reionization. We present direct measurements from QSO spectra over redshift range 5 < z 6, including first at ≃ 5.3 5.6. Our sample includes data XQR-30 VLT large program, as well new Keck/ESI observations QSOs near ∼ 5.5, which we also acquire [C ii ] 158 μ m redshifts with ALMA. By measuring Lyman continuum transmission profile in stacked...
Abstract We present Atacama Large Millimeter/submillimeter Array (ALMA) deep spectroscopy for a lensed galaxy at z spec = 8.496 with <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:mi>log</mml:mi> <mml:mo stretchy="false">(</mml:mo> <mml:msub> <mml:mrow> <mml:mi>M</mml:mi> </mml:mrow> <mml:mi>star</mml:mi> </mml:msub> stretchy="true">/</mml:mo> <mml:mo>⊙</mml:mo> stretchy="false">)</mml:mo> <mml:mo>∼</mml:mo> <mml:mn>7.8</mml:mn> </mml:math> whose optical...
Abstract We report the physical properties of 18 brightest ( S 870 μ m = 12.4–19.2 mJy) and not strongly lensed m–selected dusty star-forming galaxies (DSFGs), also known as submillimeter (SMGs), in COSMOS field. This sample is part an ALMA band 3 spectroscopic survey (AS2COSPEC), redshifts are measured 17 them at z 2–5. perform spectral energy distribution analyses deduce a median total infrared luminosity L IR (1.3 ± 0.1) × 10 13 ⊙ , infrared-based star formation rate (SFR) SFR 1390 150 M...
Abstract We investigate the properties of active galactic nuclei (AGNs) in brightest submillimeter galaxies (SMGs) COSMOS field. utilize bright sample ALMA/SCUBA-2 Survey (AS2COSMOS), which consists 260 SMGs with S 870 μ m = 0.7–19.2 mJy at z 0–6. perform optical to millimeter spectral energy distribution (SED) modeling for whole sample. identify 24 AGN-host from SEDs. Supplemented by 23 X-ray-detected AGNs (X-ray AGNs), we construct an overall 40 galaxies. The X-ray luminosity upper bounds...
We present 2D, integral field spectroscopy covering the rest-frame wavelengths of strong optical emission lines in nine submillimetre luminous galaxies (SMGs) at 2.0 < z 2.7. The Gemini-North/Near-Infrared Integral Field Spectrograph (NIFS) and Very Large Telescope (VLT) for INtegral Observations Near Infrared (SINFONI) imaging allow mapping gas morphologies dynamics within sources, we measure an average Hα velocity dispersion 〈σ〉 = 220 ± 80 km s−1 half-light radius 〈r1/2〉 3.7 0.8 kpc....
We present results from a deep 2'x3' (comoving scale of 3.7 Mpc x 5.5 at z=3) survey 1.1 mm taken with the Atacama Large Millimeter/submillimeter Array (ALMA) in SSA22 field. observe core region z = 3.09 protocluster, achieving typical rms sensitivity 60 micro-Jy/beam spatial resolution 0".7. detect 18 robust ALMA sources signal-to-noise ratio (SNR) > 5. Comparison between map and AzTEC camera on Submillimeter Telescope Experiment (ASTE) indicates that three submillimeter discovered by...
Abstract We report detections of two 1.2 mm continuum sources ( S ∼ 0.6 mJy) without any counterparts in the deep H - and/or K -band image (i.e., magnitude ≳26 mag). These near-infrared-dark faint millimeter are uncovered by ASAGAO, a and wide-field (≃26 arcmin 2 ) Atacama Large Millimeter/submillimeter Array (ALMA) survey. One has red IRAC (3.6 4.5 μ m) counterpart, other been independently detected at 850 870 m using SCUBA2 ALMA Band 7, respectively. Their optical-to-radio spectral energy...
Glowing filaments of the cosmic web Most gas in Universe lies intergalactic medium, where it forms into sheets and web. Clusters galaxies form at intersection these filaments, fed by pulled along them gravity. Although this picture is well established cosmological simulations, has been difficult to demonstrate observationally. Umehata et al. mapped emission from medium an area around that are starting a cluster (see Perspective Hamden). They found arranged whose position velocity correlate...
We analyse the molecular and atomic emission lines of 71 bright Herschel-selected galaxies between redshifts 1.4 to 4.6 detected by Atacama Large Millimetre/submillimetre Array. These include a total 156 CO, [C I], H2O lines. For 46 galaxies, we detect two transitions CO lines, for these find gas properties similar those other dusty star-forming galaxy (DSFG) samples. A comparison photo-dissociation models suggests that most have interstellar medium conditions as local infrared-luminous...
We present the results of a ~60-hr observational campaign with ALMA targeting spectroscopically confirmed and lensed sub-$L^\star$ galaxy at z=6.07, identified during Lensing Cluster Survey (ALCS). sample dust continuum emission from rest frame 90 to 370 $\mu$m six different frequencies set constraining upper limits on molecular gas line content via CO(7-6) [CI](2-1) for two images $\mu\gtrsim20$. Complementing these sub-mm observations deep optical near-IR photometry spectroscopy JWST, we...
Abstract We present a statistical study of 180 dust continuum sources identified in 33 massive cluster fields by the Atacama Large Millimeter/submillimeter Array Lensing Cluster Survey (ALCS) over total 133 arcmin 2 area, homogeneously observed at 1.2 mm. ALCS enables us to detect extremely faint millimeter lensing magnification, including near-infrared (NIR) dark objects showing no counterparts existing Hubble Space Telescope and Spitzer images. The belong blind sample ( N = 141) with...