Browsing by Author "Smail, Ian"

Now showing 1 - 8 of 8
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    ALMA Lensing Cluster Survey: ALMA-Herschel Joint Study of Lensed Dusty Star-forming Galaxies across z ≃ 0.5-6
    (2022) Sun, Fengwu; Egami, Eiichi; Fujimoto, Seiji; Rawle, Timothy; Bauer, Franz E.; Kohno, Kotaro; Smail, Ian; Perez-Gonzalez, Pablo G.; Ao, Yiping; Chapman, Scott C.; Combes, Francoise; Dessauges-Zavadsky, Miroslava; Espada, Daniel; Gonzalez-Lopez, Jorge; Koekemoer, Anton M.; Kokorev, Vasily; Lee, Minju M.; Morokuma-Matsui, Kana; Munoz Arancibia, Alejandra M.; Oguri, Masamune; Pello, Roser; Ueda, Yoshihiro; Uematsu, Ryosuke; Valentino, Francesco; van der Werf, Paul; Walth, Gregory L.; Zemcov, Michael; Zitrin, Adi
    We present an ALMA-Herschel joint analysis of sources detected by the ALMA Lensing Cluster Survey (ALCS) at 1.15 mm. Herschel/PACS and SPIRE data at 100-500 mu m are deblended for 180 ALMA sources in 33 lensing cluster fields that are detected either securely (141 sources; in our main sample) or tentatively at S/N >= 4 with cross-matched HST/Spitzer counterparts, down to a delensed 1.15 mm flux density of similar to 0.02 mJy. We performed far-infrared spectral energy distribution modeling and derived the physical properties of dusty star formation for 125 sources (109 independently) that are detected at >2 sigma in at least one Herschel band. A total of 27 secure ALCS sources are not detected in any Herschel bands, including 17 optical/near-IR-dark sources that likely reside at z = 4.2 +/- 1.2. The 16th, 50th, and 84th percentiles of the redshift distribution are 1.15, 2.08, and 3.59, respectively, for ALCS sources in the main sample, suggesting an increasing fraction of z similar or equal to 1 - 2 galaxies among fainter millimeter sources (f(1150) similar to 0.1 mJy). With a median lensing magnification factor of mu = 2.6(-0.8)(+2.6), ALCS sources in the main sample exhibit a median intrinsic star formation rate of 94(-54)(+84) M-circle dot yr(-1), lower than that of conventional submillimeter galaxies at similar redshifts by a factor of similar to 3. Our study suggests weak or no redshift evolution of dust temperature with L-IR < 10(12) L-circle dot galaxies within our sample at z similar or equal to 0 - 2. At L-IR > 10(12) L-circle dot, the dust temperatures show no evolution across z similar or equal to 1-4 while being lower than those in the local universe. For the highest-redshift source in our sample (z = 6.07), we can rule out an extreme dust temperature (>80 K) that was reported for MACS0416 Y1 at z = 8.31.
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    ALMA Lensing Cluster Survey: Bright [C ii] 158 μm Lines from a Multiply Imaged Sub-L* Galaxy at z=6.0719
    (2021) Fujimoto, Seiji; Oguri, Masamune; Brammer, Gabriel; Yoshimura, Yuki; Laporte, Nicolas; Gonzalez-Lopez, Jorge; Caminha, Gabriel B.; Kohno, Kotaro; Zitrin, Adi; Richard, Johan; Ouchi, Masami; Bauer, Franz E.; Smail, Ian; Hatsukade, Bunyo; Ono, Yoshiaki; Kokorev, Vasily; Umehata, Hideki; Schaerer, Daniel; Knudsen, Kirsten; Sun, Fengwu; Magdis, Georgios; Valentino, Francesco; Ao, Yiping; Toft, Sune; Dessauges-Zavadsky, Miroslava; Shimasaku, Kazuhiro; Caputi, Karina; Kusakabe, Haruka; Morokuma-Matsui, Kana; Shotaro, Kikuchihara; Egami, Eiichi; Lee, Minju M.; Rawle, Timothy; Espada, Daniel
    We present bright [C ii] 158 mu m line detections from a strongly magnified and multiply imaged (mu similar to 20-160) sub-L* (MUV=-19.75-0.44+0.55) Lyman-break galaxy (LBG) at z = 6.0719 +/- 0.0004, drawn from the ALMA Lensing Cluster Survey (ALCS). Emission lines are identified at 268.7 GHz at >= 8 sigma exactly at the positions of two multiple images of the LBG, behind the massive galaxy cluster RXCJ0600-2007. Our lens models, updated with the latest spectroscopy from VLT/MUSE, indicate that a sub region of the LBG crosses the caustic, and is lensed into a long (similar to 6 '') arc with a local magnification of mu similar to 160, for which the [C ii] line is also significantly detected. The source plane reconstruction resolves the interstellar medium (ISM) structure, showing that the [C ii] line is co-spatial with the rest-frame UV continuum at a scale of similar to 300 pc. The [C ii] line properties suggest that the LBG is a rotation-dominated system, whose velocity gradient explains a slight difference in redshifts between the whole LBG and its sub-region. The star formation rate (SFR)-L-[CII] relations, for whole and sub-regions of the LBG, are consistent with those of local galaxies. We evaluate the lower limit of the faint-end of the [C ii] luminosity function at z = 6, finding it to be consistent with predictions from semi-analytical models and from the local SFR-L-[CII] relation with a SFR function at z = 6. These results imply that the local SFR-L-[CII] relation is universal for a wide range of scales, including the spatially resolved ISM, the whole region of the galaxy, and the cosmic scale, even in the epoch of reionization.
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    ALMA Lensing Cluster Survey: Full Spectral Energy Distribution Analysis of z ∼ 0.5-6 Lensed Galaxies Detected with millimeter Observations
    (2024) Uematsu, Ryosuke; Ueda, Yoshihiro; Kohno, Kotaro; Toba, Yoshiki; Yamada, Satoshi; Smail, Ian; Umehata, Hideki; Fujimoto, Seiji; Hatsukade, Bunyo; Ao, Yiping; Bauer, Franz Erik; Brammer, Gabriel; Dessauges-Zavadsky, Miroslava; Espada, Daniel; Jolly, Jean-Baptiste; Koekemoer, Anton M.; Kokorev, Vasily; Magdis, Georgios E.; Oguri, Masamune; Sun, Fengwu
    Sub/millimeter galaxies are a key population for the study of galaxy evolution because the majority of star formation at high redshifts occurred in galaxies deeply embedded in dust. To search for this population, we have performed an extensive survey with Atacama Large Millimeter/submillimeter Array (ALMA), called the ALMA Lensing Cluster Survey (ALCS). This survey covers 133 arcmin(2) area and securely detects 180 sources at z similar to 0.5-6 with a flux limit of similar to 0.2 mJy at 1.2 mm. Here, we report the results of multiwavelength spectral energy distribution analysis of the whole ALCS sample, utilizing the observed-frame UV to millimeter photometry. We find that the majority of the ALCS sources lie on the star-forming main sequence, with a smaller fraction showing intense starburst activities. The ALCS sample contains high infrared-excess sources ( IRX = log ( L dust / L UV ) > 1 ), including two extremely dust-obscured galaxies (IRX > 5). We also confirm that the ALCS sample probes a broader range in lower dust mass than conventional submillimeter galaxy samples in the same redshift range. We identify six heavily obscured active galactic nucleus (AGN) candidates that are not detected in the archival Chandra data in addition to the three X-ray AGNs reported by Uematsu et al. (2023). The inferred AGN luminosity density shows a possible excess at z = 2-3 compared with that determined from X-ray surveys below 10 keV.
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    An ALMA survey of submillimetre galaxies in the Extended Chandra Deep Field South: radio properties and the far-infrared/radio correlation
    (2014) Thomson, A. P.; Ivison, R. J.; Simpson, J. M.; Swinbank, A. M.; Smail, Ian; Arumugam, V.; Alexander, D. M.; Beelen, A.; Brandt, W. N.; Chandra, I.; Dannerbauer, H.; Greve, T. R.; Hodge, J. A.; Ibar, E.; Karim, A.; Murphy, E. J.; Schinnerer, E.; Sirothia, S.; Walter, F.; Wardlow, J. L.; van der Werf, P.
    We present a study of the radio properties of 870 mu m-selected submillimetre galaxies (SMGs), observed at high resolution with Atacama Large Millimeter Array (ALMA) in the Extended Chandra Deep Field South. From our initial sample of 76 ALMA SMGs, we detect 52 SMGs at >3 sigma significance in Karl G. Jansky Very Large Array 1400 MHz imaging, of which 35 are also detected at >3 sigma in new 610 MHz Giant Metre-Wave Radio Telescope imaging. Within this sample of radio-detected SMGs, we measure a median radio spectral index a alpha(1400)(610) = -0.79 +/- 0.06, (with inter-quartile range alpha = [-1.16, -0.56]) and investigate the far-infrared/radio correlation via the parameter q(IR), the logarithmic ratio of the rest-frame 8-1000 mu m flux and monochromatic radio flux. Our median q(IR) = 2.56 +/- 0.05 (inter-quartile range q(IR) = [2.42, 2.78]) is higher than that typically seen in single-dish 870 mu m-selected sources (q(IR) similar to 2.4), which may reflect the fact that our ALMA-based study is not biased to radio-bright counterparts, as previous samples were. Finally, we search for evidence that q(IR) and alpha evolve with age in a codependent manner, as predicted by starburst models: the data populate the predicted region of parameter space, with the stellar mass tending to increase along tracks of q(IR) versus alpha in the direction expected, providing the first observational evidence in support of these models.
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    Extensive Lensing Survey of Optical and Near-infrared Dark Objects (El Sonido): HST H-faint Galaxies behind 101 Lensing Clusters
    (2021) Sun, Fengwu; Egami, Eiichi; Perez-Gonzalez, Pablo G.; Smail, Ian; Caputi, Karina I.; Bauer, Franz E.; Rawle, Timothy D.; Fujimoto, Seiji; Kohno, Kotaro; Dudzeviciute, Ugne; Atek, Hakim; Bianconi, Matteo; Chapman, Scott C.; Combes, Francoise; Jauzac, Mathilde; Jolly, Jean-Baptiste; Koekemoer, Anton M.; Magdis, Georgios E.; Rodighiero, Giulia; Rujopakarn, Wiphu; Schaerer, Daniel; Steinhardt, Charles L.; Van der Werf, Paul; Walth, Gregory L.; Weaver, John R.
    We present a Spitzer/IRAC survey of H-faint (H-160 greater than or similar to 26.4, < 5 sigma) sources in 101 lensing cluster fields. Across a CANDELS/Wide-like survey area of similar to 648 arcmin(2) (effectively similar to 221 arcmin(2) in the source plane), we have securely discovered 53 sources in the IRAC Channel-2 band (CH2, 4.5 mu m; median CH2 = 22.46 +/- 0.11 AB mag) that lack robust HST/WFC3-IR F160W counterparts. The most remarkable source in our sample, namely ES-009 in the field of Abell 2813, is the brightest H-faint galaxy at 4.5 mu m known so far (CH2 = 20.48 +/- 0.03 AB mag). We show that the H-faint sources in our sample are massive (median M-star = 10 10.3 +/- 0.3 M-circle dot, star-forming (median star formation rate =1001 M-circle dot yr(-1)), and dust-obscured (A(v) = 2.6 +/- 0.3) galaxies around a median photometric redshift of z = 3.9 +/- 0.4. The stellar continua of 14 H-faint galaxies can be resolved in the CH2 band, suggesting a median circularized effective radius (R-e,R-circ; lensing corrected) of 1.9 +/- 0.2 kpc and <1.5 kpc for the resolved and whole samples, respectively. This is consistent with the sizes of massive unobscured galaxies at z similar to 4, indicating that H-faint galaxies represent the dusty tail of the distribution of a wider galaxy population. Comparing with the ALMA dust continuum sizes of similar galaxies reported previously, we conclude that the heavy dust obscuration in H-faint galaxies is related to the compactness of both stellar and dust continua (R-e,R-circ similar to 1 kpc). These H-faint galaxies make up 161 3 % of the galaxies in the stellar-mass range of 10(10) - 10(11.2) M-circle dot at z = 3 similar to 5, contributing to 8(-4)(+8)% of the cosmic star formation rate density in this epoch and likely tracing the early phase of massive galaxy formation.
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    HERSCHEL-ATLAS: A BINARY HyLIRG PINPOINTING A CLUSTER OF STARBURSTING PROTOELLIPTICALS
    (2013) Ivison, R. J.; Swinbank, A. M.; Smail, Ian; Harris, A. I.; Bussmann, R. S.; Cooray, A.; Cox, P.; Fu, H.; Kovacs, A.; Krips, M.; Narayanan, D.; Negrello, M.; Neri, R.; Penarrubia, J.; Richard, J.; Riechers, D. A.; Rowlands, K.; Staguhn, J. G.; Targett, T. A.; Amber, S.; Baker, A. J.; Bourne, N.; Bertoldi, F.; Bremer, M.; Calanog, J. A.; Clements, D. L.; Dannerbauer, H.; Dariush, A.; De Zotti, G.; Dunne, L.; Eales, S. A.; Farrah, D.; Fleuren, S.; Franceschini, A.; Geach, J. E.; George, R. D.; Helly, J. C.; Hopwood, R.; Ibar, E.; Jarvis, M. J.; Kneib, J. -P.; Maddox, S.; Omont, A.; Scott, D.; Serjeant, S.; Smith, M. W. L.; Thompson, M. A.; Valiante, E.; Valtchanov, I.; Vieira, J.; van der Werf, P.
    Panchromatic observations of the best candidate hyperluminous infrared galaxies from the widest Herschel extragalactic imaging survey have led to the discovery of at least four intrinsically luminous z = 2.41 galaxies across an approximate to 100 kpc region-a cluster of starbursting protoellipticals. Via subarcsecond interferometric imaging we have measured accurate gas and star formation surface densities. The two brightest galaxies span similar to 3 kpc FWHM in submillimeter/radio continuum and CO J = 4-3, and double that in CO J = 1-0. The broad CO line is due partly to the multitude of constituent galaxies and partly to large rotational velocities in two counter-rotating gas disks-a scenario predicted to lead to the most intense starbursts, which will therefore come in pairs. The disks have M-dyn of several x 10(11) M-circle dot, and gas fractions of similar to 40%. Velocity dispersions are modest so the disks are unstable, potentially on scales commensurate with their radii: these galaxies are undergoing extreme bursts of star formation, not confined to their nuclei, at close to the Eddington limit. Their specific star formation rates place them greater than or similar to 5x above the main sequence, which supposedly comprises large gas disks like these. Their high star formation efficiencies are difficult to reconcile with a simple volumetric star formation law. N-body and dark matter simulations suggest that this system is the progenitor of a B(inary)-type approximate to 10(14.6)-M-circle dot cluster.
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    Panchromatic estimation of star formation rates in BzK galaxies at 1
    (2012) Kurczynski, Peter; Treister, Ezequiel; Gawiser, Eric.; Huynh, MT.; Ivison, Rob J.; Smail, Ian; Blanc, Guillermo; Cardamone, Carolin N.; Greve, Thomas R.; Schinnerer, Eva
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    The environments of Ly α blobs - I. Wide-field Ly α imaging of TN J1338-1942, a powerful radio galaxy at z ≃ 4.1 associated with a giant Ly α nebula
    (2015) Saito, Tomoki; Matsuda, Yuichi; Lacey, Cedric G.; Smail, Ian; Orsi, Alvaro; Baugh, Carlton M.; Inoue, Akio K.; Tanaka, Ichi; Yamada, Toru; Ohta, Kouji; De Breuck, Carlos; Kodama, Tadayuki; Taniguchi, Yoshiaki
    We exploit wide-field Ly alpha imaging with Subaru to probe the environment around TN J1338-1942, a powerful radio galaxy with a > 100 kpc Ly alpha halo at z = 4.11. We used a sample of Ly alpha emitters (LAEs) down to log (L-Ly alpha [erg s(-1)]) similar to 42.8 to measure the galaxy density around TN J1338-1942, compared to a control sample from a blank field taken with the same instrument. We found that TN J1338-1942 resides in a region with a peak over-density of delta(LAE) = 2.8 +/- 0.5 on scales of 8 h(-1) Mpc (on the sky) and 112 h(-1) Mpc (line of sight) in comoving coordinates. Adjacent to this overdensity, we found a strong underdensity where virtually no LAEs are detected. We used a semi-analytical model of LAEs derived from the Millennium Simulation to compare our results with theoretical predictions. While the theoretical density distribution is consistent with the blank field, overdense regions such as that around TN J1338-1942 are very rare, with a number density of 6.4 x 10(-8) Mpc(-3) (comoving), corresponding to the densest < 0.4 percentile at z similar or equal to 4.1. We also found that the Ly alpha luminosity function in the TN J1338-1942 field differs from that in the blank field: the number of bright LAEs (log(L-Ly alpha [ergs(-1)]) greater than or similar to 43.3) is enhanced, while the number of fainter LAEs is relatively suppressed. These results suggest that some powerful radio galaxies associated with Ly a nebulae reside in extreme overdensities on similar to 3-6 Mpc scales, where star formation and AGN activity may be enhanced via frequent galaxy mergers or high rates of gas accretion from the surroundings.