Browsing by Author "Kohno, K."
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- ItemALMA Lensing Cluster Survey: a strongly lensed multiply imaged dusty system at z ≥ 6(2021) Laporte, N.; Zitrin, A.; Ellis, R. S.; Fujimoto, S.; Brammer, G.; Richard, J.; Oguri, M.; Caminha, G. B.; Kohno, K.; Yoshimura, Y.; Ao, Y.; Bauer, F. E.; Caputi, K.; Egami, E.; Espada, D.; Gonzalez-Lopez, J.; Hatsukade, B.; Knudsen, K. K.; Lee, M. M.; Magdis, G.; Ouchi, M.; Valentino, F.; Wang, T.We report the discovery of an intrinsically faint, quintuply-imaged, dusty galaxy MACS0600-z6 at a redshift z = 6.07 viewed through the cluster MACSJ0600.1-2008 (z = 0.46). A similar or equal to 4 sigma dust detection is seen at 1.2mm as part of the ALMA Lensing Cluster Survey (ALCS), an on-going ALMA Large programme, and the redshift is secured via [C II] 158 mu m emission described in a companion paper. In addition, spectroscopic follow-up with GMOS/Gemini-North shows a break in the galaxy's spectrum, consistent with the Lyman break at that redshift. We use a detailed mass model of the cluster and infer a magnification mu greater than or similar to 30 for the most magnified image of this galaxy, which provides an unprecedented opportunity to probe the physical properties of a sub-luminous galaxy at the end of cosmic reionization. Based on the spectral energy distribution, we infer lensing-corrected stellar and dust masses of 2.9(-2.3)(+11.5) x 10(9) and 4.8(-3.4)(+4.5) x 10(6) M-circle dot, respectively, a star formation rate of 9.7(-6.6)(+22.0) M-circle dot yr(-1), an intrinsic size of 0.54(-0.14)(+0.26) kpc, and a luminosity-weighted age of 200 +/- 100 Myr. Strikingly, the dust production rate in this relatively young galaxy appears to be larger than that observed for equivalent, lower redshift sources. We discuss if this implies that early supernovae are more efficient dust producers and the consequences for using dust mass as a probe of earlier star formation.
- ItemALMA Lensing Cluster Survey: Hubble Space Telescope and Spitzer Photometry of 33 Lensed Fields Built with CHArGE(2022) Kokorev, V; Brammer, G.; Fujimoto, S.; Kohno, K.; Magdis, G. E.; Valentino, F.; Toft, S.; Oesch, P.; Davidzon, I; Bauer, F. E.; Coe, D.; Egami, E.; Oguri, M.; Ouchi, M.; Postman, M.; Richard, J.; Jolly, J-B; Knudsen, K. K.; Sun, F.; Weaver, J. R.; Ao, Y.; Baker, A. J.; Bradley, L.; Caputi, K., I; Dessauges-Zavadsky, M.; Espada, D.; Hatsukade, B.; Koekemoer, A. M.; Arancibia, A. M. Munoz; Shimasaku, K.; Umehata, H.; Wang, T.; Wang, W-HWe present a set of multiwavelength mosaics and photometric catalogs in the Atacama Large Millimeter/submillimeter Array (ALMA) lensing cluster survey fields. The catalogs were built by the reprocessing of archival data from the Complete Hubble Archive for Galaxy Evolution compilation, taken by the Hubble Space Telescope (HST) in the Reionization Lensing Cluster Survey, Cluster Lensing And Supernova survey with Hubble, and Hubble Frontier Fields. Additionally, we have reconstructed the Spitzer Infrared Array Camera 3.6 and 4.5 mu m mosaics, by utilizing all the available archival IPAC Infrared Science Archive/Spitzer Heritage Archive exposures. To alleviate the effect of blending in such a crowded region, we have modeled the Spitzer photometry by convolving the HST detection image with the Spitzer point-spread function using the novel GOLFIR software. The final catalogs contain 218,000 sources, covering a combined area of 690 arcmin(2) , a factor of similar to 2 improvement over the currently existing photometry. A large number of detected sources is a result of reprocessing of all available and sometimes deeper exposures, in conjunction with a combined optical-near-IR detection strategy. These data will serve as an important tool in aiding the search of the submillimeter galaxies in future ALMA surveys, as well as follow-ups of the HST dark and high-z sources with JWST. Coupled with the available HST photometry, the addition of the 3.6 and 4.5 mu m bands will allow us to place a better constraint on the photometric redshifts and stellar masses of these objects, thus giving us an opportunity to identify high-redshift candidates for spectroscopic follow-ups and to answer the important questions regarding the Epoch of Reionization and formation of the first galaxies. The mosaics, photometric catalogs, and the best-fit physical properties are publicly available at https:// github.com/dawn-cph/alcs-clusters.
- ItemHerMES: THE CONTRIBUTION TO THE COSMIC INFRARED BACKGROUND FROM GALAXIES SELECTED BY MASS AND REDSHIFT(2013) Viero, M. P.; Moncelsi, L.; Quadri, R. F.; Arumugam, V.; Assef, R. J.; Bethermin, M.; Bock, J.; Bridge, C.; Casey, C. M.; Conley, A.; Cooray, A.; Farrah, D.; Glenn, J.; Heinis, S.; Ibar, E.; Ikarashi, S.; Ivison, R. J.; Kohno, K.; Marsden, G.; Oliver, S. J.; Roseboom, I. G.; Schulz, B.; Scott, D.; Serra, P.; Vaccari, M.; Vieira, J. D.; Wang, L.; Wardlow, J.; Wilson, G. W.; Yun, M. S.; Zemcov, M.We quantify the fraction of the cosmic infrared background (CIB) that originates from galaxies identified in the UV/optical/near-infrared by stacking 81,250 (similar to 35.7 arcmin(-2)) K-selected sources (K-AB < 24.0) split according to their rest-frame U-V versus V-J colors into 72,216 star-forming and 9034 quiescent galaxies, on maps from Spitzer/MIPS (24 mu m), Herschel/PACS (100, 160 mu m), Herschel/SPIRE (250, 350, 500 mu m), and AzTEC (1100 mu m). The fraction of the CIB resolved by our catalog is (69% +/- 15%) at 24 mu m, (78% +/- 17%) at 70 mu m, (58% +/- 13%) at 100 mu m, (78% +/- 18%) at 160 mu m, (80% +/- 17%) at 250 mu m, (69% +/- 14%) at 350 mu m, (65% +/- 12%) at 500 mu m, and (45% +/- 8%) at 1100 mu m. Of that total, about 95% originates from star-forming galaxies, while the remaining 5% is from apparently quiescent galaxies. The CIB at lambda less than or similar to 200 mu m appears to be sourced predominantly from galaxies at z less than or similar to 1, while at. greater than or similar to 200 mu m the bulk originates from 1 less than or similar to z less than or similar to 2. Galaxies with stellar masses log(M/M-circle dot) = 9.5-11 are responsible for the majority of the CIB, with those in the log(M/M-circle dot) = 9.5-10 bin contributing mostly at lambda < 250 mu m, and those in the log(M/M circle dot) = 10-11 bin dominating at lambda > 350 mu m. The contribution from galaxies in the log(M/M-circle dot) = 9.0-9.5 (lowest) and log(M/M-circle dot) = 11.0-12.0 (highest) stellar-mass bins contribute the least-both of order 5%-although the highest stellar-mass bin is a significant contributor to the luminosity density at z greater than or similar to 2. The luminosities of the galaxies responsible for the CIB shifts from combinations of "normal" and luminous infrared galaxies (LIRGs) at lambda less than or similar to 160 mu m, to LIRGs at 160 less than or similar to lambda less than or similar to 500 mu m, to finally LIRGs and ultra-luminous infrared galaxies at lambda greater than or similar to 500 mu m. Stacking analyses were performed using SIMSTACK, a novel algorithm designed to account for possible biases in the stacked flux density due to clustering. It is made available to the public at www.astro.caltech.edu/similar to viero/viero_homepage/toolbox.html.
- ItemHerschel reveals the obscured star formation in HiZELS Hα emitters at z=1.47(2013) Ibar, E.; Sobral, D.; Best, P. N.; Ivison, R. J.; Smail, I.; Arumugam, V.; Berta, S.; Bethermin, M.; Bock, J.; Cava, A.; Conley, A.; Farrah, D.; Geach, J.; Ikarashi, S.; Kohno, K.; Le Floc'h, E.; Lutz, D.; Magdis, G.; Magnelli, B.; Marsden, G.; Oliver, S. J.; Page, M. J.; Pozzi, F.; Riguccini, L.; Schulz, B.; Seymour, N.; Smith, A. J.; Symeonidis, M.; Wang, L.; Wardlow, J.; Zemcov, M.We describe the far-infrared (far-IR; rest-frame 8-1000-mu m) properties of a sample of 443 H alpha-selected star-forming galaxies in the Cosmic Evolution Survey (COSMOS) and Ultra Deep Survey (UDS) fields detected by the High-redshift Emission Line Survey (HiZELS) imaging survey. Sources are identified using narrow-band filters in combination with broad-band photometry to uniformly select H alpha (and [O ii] if available) emitters in a narrow redshift slice at z = 1.47 +/- 0.02. We use a stacking approach in Spitzer-MIPS mid-IR, Herschel-PACS/SPIRE far-IR [from the PACS Evolutionary Prove (PEP) and Herschel Multi-tiered Extragalactic Survey (HerMES)] and AzTEC mm-wave images to describe their typical far-IR properties. We find that HiZELS galaxies with observed H alpha luminosities of L(H alpha)(obs) approximate to 10(8.1-9.1) L-circle dot ( approximate to 10(41.7-42.7) erg s(-1)) have bolometric far-IR luminosities of typical luminous IR galaxies, L(8-1000 mu m) approximate to 10(-0.006)(11.41)(+0.04) L-circle dot. Combining the H alpha and far-IR luminosities, we derive median star formation rates (SFRs) of SFRH alpha, FIR = 32 +/- 5 M-circle dot yr(-1) and H alpha extinctions of A(H alpha) = 1.0 +/- 0.2 mag. Perhaps surprisingly, little difference is seen in typical HiZELS extinction levels compared to local star-forming galaxies. We confirm previous empirical stellar mass (M-*) to A(H alpha) relations and the little or no evolution up to z = 1.47. For HiZELS galaxies (or similar samples) we provide an empirical parametrization of the SFR as a function of rest-frame (u - z) colours and 3.6-mu m photometry - a useful proxy to aid in the absence of far-IR detections in high-z galaxies. We find that the observed H alpha luminosity is a dominant SFR tracer when rest-frame (u - z) colours are less than or similar to 0.9 mag or when Spitzer-3.6-mu m photometry is fainter than 22 mag (Vega) or when stellar masses are lower than 10(9.7) M-circle dot. We do not find any correlation between the [O ii]/H alpha and far-IR luminosity, suggesting that this emission line ratio does not trace the extinction of the most obscured star-forming regions, especially in massive galaxies where these dominate. The luminosity-limited HiZELS sample tends to lie above of the so-called main sequence for star-forming galaxies, especially at low stellar masses, indicating high star formation efficiencies in these galaxies. This work has implications for SFR indicators and suggests that obscured star formation is linked to the assembly of stellar mass, with deeper potential wells in massive galaxies providing dense, heavily obscured environments in which stars can form rapidly.
- ItemThe cold interstellar medium of a normal sub-L* galaxy at the end of reionization(2024) Valentino, F.; Fujimoto, S.; Gimenez-Arteaga, C.; Brammer, G.; Kohno, K.; Sun, F.; Kokorev, V.; Bauer, F. E.; Di Cesare, C.; Espada, D.; Lee, M.; Dessauges-Zavadsky, M.; Ao, Y.; Koekemoer, A. M.; Ouchi, M.; Wu, J. F.; Egami, E.; Jolly, J. -b.; Lagos, C. del P.; Magdis, G. E.; Schaerer, D.; Shimasaku, K.; Umehata, H.; Wang, W. -h.We present the results of a similar to 60-h multiband observational campaign with the Atacama Large Millimeter Array targeting a spectroscopically confirmed and lensed sub-L* galaxy at z = 6.07, first identified during the ALMA Lensing Cluster Survey (ALCS). We sampled the dust continuum emission from rest frame 90-370 mu m at six different frequencies and set constraining upper limits on the molecular gas line emission and content by targeting the CO (7 - 6) and [C I](P-3(2)-P-3(1)) transitions in two lensed images with mu greater than or similar to 20. Complementing these submillimeter observations with deep optical and near-IR photometry and spectroscopy with JWST, we find this galaxy to form stars at a rate of SFR similar to 7 M-circle dot yr(-1), similar to 50 - 70% of which is obscured by dust. This is consistent with what one would predict for a M-* similar to 7.5 x 10(8) M-circle dot object by extrapolating the relation between the fraction of the obscured star formation rate and stellar mass at z < 2.5 and with observations of IR-detected objects at 5 < z < 7. The light-weighted dust temperature of T-dust similar to 50 K is similar to that of more massive galaxies at similar redshifts, although with large uncertainties and with possible negative gradients. We measure a dust mass of M-dust similar to 1.5 x 10(6) M-circle dot and, by combining [C I], [C II], and a dynamical estimate, a gas mass of M-gas similar to 2 x 10(9) M-circle dot. Their ratio (delta(DGR)) is in good agreement with predictions from models and empirical relations in the literature. The dust-to-stellar mass fraction of f(dust) similar to 0.002 and the young stellar age (100 - 200 Myr) are consistent with efficient dust production via supernovae, as predicted by existing models and simulations of dust evolution. Also, the expected number density of galaxies with M-dust similar to 10(6) M-circle dot at z = 6 from a subset of these models is in agreement with the observational estimate that we set from the parent ALCS survey. The combination of gravitational lensing and deep multiwavelength observations allowed us to probe luminosity and mass regimes up to two orders of magnitude lower than what has been explored so far for field galaxies at similar redshifts. Our results serve as a benchmark for future observational endeavors of the high-redshift and faint sub-L* galaxy population that might have driven the reionization of the Universe.
- ItemThe Gas and Stellar Content of a Metal-poor Galaxy at z=8.496 as Revealed by JWST and ALMA(2023) Heintz, K. E.; Gimenez-Arteaga, C.; Fujimoto, S.; Brammer, G.; Espada, D.; Gillman, S.; Gonzalez-Lopez, J.; Greve, T. R.; Harikane, Y.; Hatsukade, B.; Knudsen, K. K.; Koekemoer, A. M.; Kohno, K.; Kokorev, V.; Lee, M. M.; Magdis, G. E.; Nelson, E. J.; Rizzo, F.; Sanders, R. L.; Schaerer, D.; Shapley, A. E.; Strait, V. B.; Toft, S.; Valentino, F.; van der Wel, A.; Vijayan, A. P.; Watson, D.; Bauer, F. E.; Christiansen, C. R.; Wilson, S. N.We present a joint analysis of the galaxy S04590 at z = 8.496 based on NIRSpec, NIRCam, and NIRISS observations obtained as part of the Early Release Observations program of the James Webb Space Telescope (JWST) and the far-infrared [C ii] 158 mu m emission line detected by dedicated Atacama Large Millimeter/submillimeter Array (ALMA) observations. We determine the physical properties of S04590 from modeling of the spectral energy distribution (SED) and through the redshifted optical nebular emission lines detected with JWST/NIRSpec. The best-fit SED model reveals a low-mass (M-? = 10(7.2)-10(8) M-?) galaxy with a low oxygen abundance of derived from the strong nebular and auroral emission lines. Assuming that [C ii] effectively traces the interstellar medium, we estimate the total gas mass of the galaxy to be M-gas = (8.0 +/- 4.0) x 10(8) M-? based on the luminosity and spatial extent of [C ii]. This yields an exceptionally high gas fraction, f(gas) = M-gas/(M-gas + M-?) ? 90%, though one still consistent with the range expected for low metallicity. We further derive the metal mass of the galaxy based on the gas mass and gas-phase metallicity, which we find to be consistent with the expected metal production from Type II supernovae. Finally, we make the first constraints on the dust-to-gas (DTG) and dust-to-metal (DTM) ratios of galaxies in the epoch of reionization at z ? 6, showing overall low mass ratios of logDTG < -3.8 and logDTM < -0.5, though they are consistent with established scaling relations and in particular with those of the local metal-poor galaxy I Zwicky 18. Our analysis highlights the synergy between ALMA and JWST in characterizing the gas, metal, and stellar content of the first generation of galaxies.