Browsing by Title
A CEERS Discovery of an Accreting Supermassive Black Hole 570 Myr after the Big Bang: Identifying a Progenitor of Massive z > 6 Quasars
(IOP Publishing Ltd, 2023/08/01) Larson, Rebecca L., Finkelstein, Steven D., Kocevski, Dale A., Hutchison, Taylor R., Trump, Jonathan, Haro, Pablo Arrabal, Bromm, Volker J., Cleri, Nikko, Dickinson, Mark, Fujimoto, Seiji S., Kartaltepe, Jeyhan M., Koekemoer, Anton, Papovich, Casey, Pirzkal, Nor, Tacchella, Sandro A., Zavala, Jorge, Bagley, Micaela, Behroozi, Peter B., Champagne, Jaclyn W., Cole, Justin, Jung, Intae M., Morales, Alexa, Yang, Guang, Zhang, Haowen, Zitrin, Adi O., Amorin, Ricardo, Burgarella, Denis M., Casey, Caitlin, Ortiz, Oscar A. Chavez G., Cox, Isabella, Chworowsky, Katherine, Fontana, Adriano, Gawiser, Eric, Grazian, Andrea A., Grogin, Norman, Harish, Santosh P., Hathi, Nimish, Hirschmann, Michaela W., Holwerda, Benne, Juneau, Stephanie, Leung, Gene C. K. A., Lucas, Ray J., McGrath, Elizabeth G., Perez-Gonzalez, Pablo R., Rigby, Jane, Seille, Lise-Marie C., Simons, Raymond, de la Vega, Alexander J., Weiner, Benjamin M., Wilkins, Stephen, Yung, L. Y. Aaron
We report the discovery of an accreting supermassive black hole at z = 8.679. This galaxy, denoted here as CEERS_1019, was previously discovered as a Ly & alpha,-break galaxy by Hubble with a Ly & alpha, redshift from Keck. As part of the Cosmic Evolution Early Release Science (CEERS) survey, we have observed this source with JWST/NIRSpec, MIRI, NIRCam, and NIRCam/WFSS and uncovered a plethora of emission lines. The H & beta, line is best fit by a narrow plus a broad component, where the latter is measured at 2.5 & sigma, with an FWHM & SIM,1200 km s(-1). We conclude this originates in the broadline region of an active galactic nucleus (AGN). This is supported by the presence of weak high-ionization lines (N V, N IV], and C III]), as well as a spatial point-source component. The implied mass of the black hole (BH) is log (M (BH)/M (& ODOT,)) = 6.95 & PLUSMN, 0.37, and we estimate that it is accreting at 1.2 & PLUSMN, 0.5 times the Eddington limit. The 1-8 & mu,m photometric spectral energy distribution shows a continuum dominated by starlight and constrains the host galaxy to be massive (log M/M-& ODOT, & SIM,9.5) and highly star-forming (star formation rate, or SFR & SIM, 30 M-& ODOT, yr(-1), log sSFR & SIM, - 7.9 yr(-1)). The line ratios show that the gas is metal-poor (Z/Z (& ODOT,) & SIM, 0.1), dense (n (e) & SIM, 10(3) cm(-3)), and highly ionized (log U & SIM, - 2.1). We use this present highest-redshift AGN discovery to place constraints on BH seeding models and find that a combination of either super-Eddington accretion from stellar seeds or Eddington accretion from very massive BH seeds is required to form this object.
A CO funnel in the Galactic centre: Molecular counterpart of the northern Galactic chimney
(EDP SCIENCES S A, 2023/06/27) Veena, V. S., Riquelme, D., Kim, W. -J., Menten, K. M., Schilke, P., Sormani, M. C., Banda-Barragan, W. E., Wyrowski, F., Fuller, G. A., Cheema, A.
We report the discovery of a velocity coherent, funnel-shaped (CO)-C-13 emission feature in the Galactic centre (GC) using data from the SEDIGISM survey. The molecular cloud appears as a low-velocity structure (V-LSR  = [ - 3.5,   + 3.5] km s(-1)) with an angular extent of 0.95 & DEG, x1 & DEG,, extending towards positive Galactic latitudes. The structure is offset from Sgr A* towards negative Galactic longitudes, it spatially and morphologically correlates well with the northern lobe of the 430 pc radio bubble, believed to be the radio counterpart of the multiwavelength GC chimney. Spectral line observations in the frequency range of 85-116 GHz have been carried out using the IRAM 30-m telescope towards 12 positions along the funnel-shaped emission. We examine the C-12/C-13 isotopic ratios using various molecules and their isotopologues. The mean C-12/C-13 isotope ratio (30.6 & PLUSMN, 2.9) is consistent with the structure located within inner 3 kpc of the Galaxy and possibly in the GC. The velocity of the molecular funnel is consistent with previous radio recombination line measurements of the northern lobe of radio bubble. Our multiwavelength analysis suggests that the funnel-shaped structure extending over 100 pc above the Galactic plane is the molecular counterpart of the northern GC chimney.
A melting-pot for Pterodroma petrels on Rapa Nui: ecological divergence and reproductive isolation in a contact zone
(FRONTIERS MEDIA SA, 2023/07/27) Plaza Paula, Cristofari Robin, Gouin Nicolas, Soto-Gamboa Mauricio, Luna-Jorquera Guillermo
Speciation is thought to depend on general ecological segregation rather than on strict allopatry in species with planetary-scale foraging ranges, such as Pterodroma petrels. Separation in both breeding islands and foraging grounds are generally considered to be the conditions for prezygotic isolation. However, it is unclear how both can be maintained in a context of ongoing distributional range shifts due to global change, with range contractions and expansions caused by changing land use in breeding territories and oceanographic conditions impacting productivity areas. In this context, we expect that wherever the fragile balance of allopatric segregation breaks down, gene flow may be re-established across the borders of what is currently considered separated species. In these melting pot areas, fine-scale ecological differentiation is likely the only force opposing panmixia in otherwise highly similar organisms. In this study, we focus on six Polynesian Pterodroma species currently found on Motu Nui, a protected islet offshore of Rapa Nui (Easter Island), four of which have likely extended their breeding range to that island recently. To understand the fine-scale interaction between these closely-related species in their new contact zone, we used an integrative approach combining ecological and genetic methods, including morphometric, bioacoustics, stable isotope niche reconstruction, breeding site characterisation, phenology traits, and both nuclear and mitochondrial DNA markers. We found that significant amounts of gene flow occur across what is currently considered species boundaries, sometimes questioning the relevance of the accepted species classification. Interestingly, our results indicate that multivariate ecological distance between individuals in a group of closely related species (P. alba, P. atrata, P. heraldica, and P. neglecta) is a relevant predictor of gene flow intensity, while more distant species such as P. ultima and P. nigripennis seem to maintain reproductive isolation. Thus, the case of Pterodroma petrels supports the idea that incomplete allopatric speciation processes may be halted or even reversed on a secondary contact zone. Beyond their direct taxonomical relevance, our results underline the importance of considering fine ecological structures for biodiversity mapping and conservation policies.
A melting-pot for Pterodroma petrels on Rapa Nui: ecological divergence and reproductive isolation in a contact zone
(2023/07/27) Plaza Paula; Cristofari Robin; Gouin Nicolas; Soto-Gamboa Mauricio; Luna-Jorquera Guillermo
Speciation is thought to depend on general ecological segregation rather than on strict allopatry in species with planetary-scale foraging ranges, such as Pterodroma petrels. Separation in both breeding islands and foraging grounds are generally considered to be the conditions for prezygotic isolation. However, it is unclear how both can be maintained in a context of ongoing distributional range shifts due to global change, with range contractions and expansions caused by changing land use in breeding territories and oceanographic conditions impacting productivity areas. In this context, we expect that wherever the fragile balance of allopatric segregation breaks down, gene flow may be re-established across the borders of what is currently considered separated species. In these melting pot areas, fine-scale ecological differentiation is likely the only force opposing panmixia in otherwise highly similar organisms. In this study, we focus on six Polynesian Pterodroma species currently found on Motu Nui, a protected islet offshore of Rapa Nui (Easter Island), four of which have likely extended their breeding range to that island recently. To understand the fine-scale interaction between these closely-related species in their new contact zone, we used an integrative approach combining ecological and genetic methods, including morphometric, bioacoustics, stable isotope niche reconstruction, breeding site characterisation, phenology traits, and both nuclear and mitochondrial DNA markers. We found that significant amounts of gene flow occur across what is currently considered species boundaries, sometimes questioning the relevance of the accepted species classification. Interestingly, our results indicate that multivariate ecological distance between individuals in a group of closely related species (P. alba, P. atrata, P. heraldica, and P. neglecta) is a relevant predictor of gene flow intensity, while more distant species such as P. ultima and P. nigripennis seem to maintain reproductive isolation. Thus, the case of Pterodroma petrels supports the idea that incomplete allopatric speciation processes may be halted or even reversed on a secondary contact zone. Beyond their direct taxonomical relevance, our results underline the importance of considering fine ecological structures for biodiversity mapping and conservation policies.
A MUSE view of the multiple interacting system HCG 31
(OXFORD UNIV PRESS, 2023/04/21) Gomez-Espinoza, Diego A., Torres-Flores, S., Firpo, V, Amram, Philippe, Epinat, Benoit, Contini, Thierry, de Oliveira, Claudia Mendes
We present, for the first time, spatially resolved spectroscopy for the entire Hickson Compact Group 31 obtained with the MUSE instrument at the VLT and an in-depth analysis of this compact group. To obtain a complete understanding of the system, we derived radial velocity and dispersion velocity maps, maps of the ionization mechanism of the system, chemical abundances and their distribution over the whole system, star formation rates and ages of the different star-forming regions, and the spatial distribution of the Wolf-Rayet stellar population. We also reconstructed the star formation history of the galaxies HCG 31 A, C, B, and F, measured the emission-line fluxes, and performed a stellar population synthesis. Our main findings are: (i) that there is clearly disturbed kinematics due to the merger event that the system is experiencing, (ii) that the ionization is produced exclusively via star formation except for the nucleus of the galaxy HCG 31 A, where there is a small contribution of shocks, (iii) that there is low oxygen abundance distributed homogeneously through the system, (iv) that there is a prominent population of carbon Wolf-Rayet stars in the central zone of the group, and (v) that there are clear evidences of the tidal origin of the galaxies HCG 31 E, HCG 31 H, and HCG 31 F because they show quite high oxygen abundances for their stellar mass. All these findings are clear evidence that HCG 31 is currently in an early merging phase and manifesting a starburst in its central region.
A MUSE/VLT spatially resolved study of the emission structure of Green Pea galaxies
(EDP SCIENCES S A, 2023/09/15) Arroyo-Polonio, A., Iglesias-Paramo, J., Kehrig, C., Vilchez, J. M., Amorin, R., Breda, I., Perez-Montero, E., Perez-Diaz, B., Hayes, M.
Green Pea galaxies (GPs) present among the most intense starbursts known in the nearby Universe. These galaxies are regarded as local analogs of high-redshift galaxies, making them a benchmark in the understanding of the star formation processes and the galactic evolution in the early Universe. In this work, we performed an integral field spectroscopic (IFS) study for a set of 24 GPs to investigate the interplay between its ionized interstellar medium (ISM) and the massive star formation that these galaxies present. Observations were taken in the optical spectral range (lambda 4750 angstrom-lambda 9350 angstrom) with the MUSE spectrograph attached to the 8.2m telescope VLT. Spatial extension criteria were employed to verify which GPs are spatially resolved in the MUSE data cubes. We created and analyzed maps of spatially distributed emission lines (at di fferent stages of excitation), continuum emission, and properties of the ionized ISM (e.g., ionization structure indicators, physical-chemical conditions, dust extinction). We also took advantage of our IFS data to produce integrated spectra of selected galactic regions in order to study their physical-chemical conditions. Maps of relevant emission lines and emission line ratios show that higher-excitation gas is preferentially located in the center of the galaxy, where the starburst is present. The continuum maps, with an average angular extent of 4 '', exhibit more complex structures than the emission line maps. However, the [OIII]lambda 5007 angstrom emission line maps tend to extend beyond the continuum images (the average angular extent is 5.5 ''), indicating the presence of low surface brightness ionized gas in the outer parts of the galaxies. H alpha/H beta, [SII]/H alpha, and [OI]/H alpha maps trace low-extinction, optically thin regions. The line ratios [OIII]/H beta and [NII]/H alpha span extensive ranges, with values varying from 0.5 dex to 0.9 dex and from 1.7 dex to 0.8 dex, respectively. Regarding the integrated spectra, the line ratios were fit to derive physical properties including the electron densities n(e) = 30-530 cm(-3), and, in six GPs with a measurable [OIII]lambda 4363 angstrom line, electron temperatures of T-e = 11 500 K-15 500 K, so the direct method was applied in these objects to retrieve metallicities 12 + log(O/H) similar or equal to 8. We found the presence of the high-ionizing nebular HeII lambda 4686 angstrom line in three GPs, where two of them present among the highest sSFR values ( >8 x 10(8) yr(-1)) in this sample. Non-Wolf-Rayet (WR) features are detected in these galaxy spectra.
A reproduction of the Milky Way's Faraday rotation measure map in galaxy simulations from global to local scales
(NATURE PORTFOLIO, 2023/11/01) Reissl, Stefan, Klessen, Ralf S. S., Pellegrini, Eric W. W., Rahner, Daniel, Pakmor, Rudiger, Grand, Robert, Gomez, Facundo, Marinacci, Federico, Springel, Volker
Magnetic fields are of critical importance for our understanding of the origin and long-term evolution of the Milky Way. This is due to their decisive role in the dynamical evolution of the interstellar medium and their influence on the star-formation process(1-3). Faraday rotation measures along many different sightlines across the Galaxy are a primary means to infer the magnetic field topology and strength from observations(4-7). However, the interpretation of the data has been hampered by the failure of previous attempts to explain the observations in theoretical models and to synthesize a realistic multiscale all-sky rotation measures map(8-10). We here utilize a cosmological magnetohydrodynamic simulation of the formation of the Milky Way, augment it with a new star-cluster population-synthesis model for a more realistic structure of the local interstellar medium(11,12), and perform detailed polarized radiative transfer calculations on the resulting model(13). This yields an accurate first-principles prediction of the Faraday sky as observed on Earth. The results reproduce the observations of the Galaxy not only on global scales but also on local scales of individual star-forming clouds. They also indicate that the Local Bubble(14) containing our Sun dominates the rotation measures signal over large regions of the sky. Modern cosmological magnetohydrodynamic simulations of the Milky Way's formation, combined with a plausible model for star formation, stellar feedback and the distribution of free electrons in the interstellar medium, explain the rotation measures observations remarkably well, and thus contribute to a better understanding of the origin of magnetic fields in our Galaxy.
A search for heavy Higgs bosons decaying into vector bosons in same-sign two-lepton final states in pp collisions at ?s=13 TeV with the ATLAS detector
(SPRINGER, 2023/07/26) Aad G.; Abbott B.; Abbott D. C.; Abeling K.; Abidi S. H.; Aboulhorma A.; Abramowicz H.; Abreu H.; Abulaiti Y.; Abusleme Hoffman A. C.; Acharya B. S.; Achkar B.; Adam L.; Adam Bourdarios C.; Adamczyk L.; Adamek L.; Addepalli S. V.; Adelman J.; Adiguzel A.; Adorni S.; Adye T.; Affolder A. A.; Afik Y.; Agaras M. N.; Agarwala J.; Aggarwal A.; Agheorghiesei C.; Aguilar-Saavedra J. A.; Ahmad A.; Ahmadov F.; Ahmed W. S.; Ai X.; Aielli G.; Aizenberg I.; Akbiyik M.; Akesson T. P. A.; Akimov A. V.; Al Khoury K.; Alberghi G. L.; Albert J.
A search for heavy Higgs bosons produced in association with a vector boson and decaying into a pair of vector bosons is performed in final states with two leptons (electrons or muons) of the same electric charge, missing transverse momentum and jets. A data sample of proton-proton collisions at a centre-of-mass energy of 13 TeV recorded with the ATLAS detector at the Large Hadron Collider between 2015 and 2018 is used. The data correspond to a total integrated luminosity of 139 fb(-1). The observed data are in agreement with Standard Model background expectations. The results are interpreted using higher-dimensional operators in an effective field theory. Upper limits on the production cross-section are calculated at 95% confidence level as a function of the heavy Higgs boson's mass and coupling strengths to vector bosons. Limits are set in the Higgs boson mass range from 300 to 1500 GeV, and depend on the assumed couplings. The highest excluded mass for a heavy Higgs boson with the coupling combinations explored is 900 GeV. Limits on coupling strengths are also provided.
A search for new resonances in multiple final states with a high transverse momentum Z boson in ?s=13 TeV pp collisions with the ATLAS detector
(SPRINGER, 2023/06/07) Aad G.; Abbott B.; Abbott D. C.; Abeling K.; Abidi S. H.; Aboulhorma A.; Abramowicz H.; Abreu H.; Abulaiti Y.; Abusleme Hoffman A. C.; Acharya B. S.; Achkar B.; Adam Bourdarios C.; Adamczyk L.; Adamek L.; Addepalli S. V.; Adelman J.; Adiguzel A.; Adorni S.; Adye T.; Affolder A. A.; Afik Y.; Agaras M. N.; Agarwala J.; Aggarwal A.; Agheorghiesei C.; Aguilar-Saavedra J. A.; Ahmad A.; Ahmadov F.; Ahmed W. S.; Ahuja S.; Ai X.; Aielli G.; Aizenberg I.; Akbiyik M.; Akesson T. P. A.; Akimov A. V.; Al Khoury K.; Alberghi G. L.; Albert J.
A generic search for resonances is performed with events containing a Z boson with transverse momentum greater than 100 GeV, decaying into e(+)e(-) or mu(+)mu(-). The analysed data collected with the ATLAS detector in proton-proton collisions at a centre-of-mass energy of 13TeV at the Large Hadron Collider correspond to an integrated luminosity of 139 fb(-1). Two invariant mass distributions are examined for a localised excess relative to the expected Standard Model background in six independent event categories (and their inclusive sum) to increase the sensitivity. No significant excess is observed. Exclusion limits at 95% confidence level are derived for two cases: a model-independent interpretation of Gaussian-shaped resonances with the mass width between 3% and 10% of the resonance mass, and a specific heavy vector triplet model with the decay mode W' -> ZW -> llqq.
A trail of the invisible: blue globular clusters trace the radial density distribution of the dark matter - case study of NGC 4278
(OXFORD UNIV PRESS, 2023/03/31) Kluge, Matthias, Remus, Rhea-Silvia, Babyk, Iurii, V, Forbes, Duncan A., Dolfi, Arianna
We present new, deep optical observations of the early-type galaxy NGC 4278, which is located in a small loose group. We find that the galaxy lacks fine substructure, that is, it appears relaxed, out to a radius of similar to 70 kpc. Our g- and i-band surface brightness profiles are uniform down to our deepest levels of similar to 28 mag arcsec(-2). This spans an extremely large radial range of more than 14 half-mass radii. Combined with archival globular cluster (GC) number density maps and a new analysis of the total mass distribution obtained from archival Chandra X-ray data, we find that the red GC subpopulation traces well the stellar mass density profile from 2.4 out to even 14 half-mass radii, while the blue GC subpopulation traces the total mass density profile of the galaxy over a large radial range. Our results reinforce the scenario that red GCs form mostly in situ along with the stellar component of the galaxy, while the blue GCs are more closely aligned with the total mass distribution in the halo and were accreted along with halo matter. We conclude that for galaxies where the X-ray emission from the hot halo is too faint to be properly observable and as such is not available to measure the dark matter profile, the blue GC population can be used to trace this dark matter component out to large radii.
ABYSS. I. Targeting Strategy for the APOGEE and BOSS Young Star Survey in SDSS-V
(IOP Publishing Ltd, 2023/05/01) Kounkel, Marina, Zari, Eleonora, Covey, Kevin, Tkachenko, Andrew, Zuniga, Carlos Roman, Stassun, Keivan, Stutz, Amelia M., Stringfellow, Guy, Roman-Lopes, Alexandre, Hernandez, Jesus, Ramirez, Karla Pena, Bayo, Amelia, Kim, Jinyoung Serena, Cao, Lyra, Wolk, Scott J., Kollmeier, Juna, Lopez-Valdivia, Ricardo, Rojas-Ayala, Barbara
The fifth iteration of the Sloan Digital Sky Survey is set to obtain optical and near-infrared spectra of similar to 5 million stars of all ages and masses throughout the Milky Way. As a part of these efforts, APOGEE and BOSS Young Star Survey (ABYSS) will observe similar to 10(5) stars with ages <30 Myr that have been selected using a set of homogeneous selection functions that make use of different tracers of youth. The ABYSS targeting strategy we describe in this paper is aimed to provide the largest spectroscopic census of young stars to date. It consists of eight different types of selection criteria that take the position on the H-R diagram, infrared excess, variability, as well as the position in phase space in consideration. The resulting catalog of similar to 200,000 sources (of which a half are expected to be observed) provides representative coverage of the young Galaxy, including both nearby diffuse associations as well as more distant massive complexes, reaching toward the inner Galaxy and the Galactic center.
Adaptive plasticity to drought of Grime's CSR strategies
(WILEY, 2023/11/01) Escobedo Victor M., Molina-Montenegro Marco A., Salgado-Luarte Cristian, Stotz Gisela C., Gianoli Ernesto
Grime's strategies (competitor, stress tolerator, ruderal, CSR) represent viable trait combinations with which species deal with environmental conditions. CSR strategies are broadly used to understand plant adaptation to the environment, yet their plastic responses have received little attention. A globally-calibrated tool (StrateFy) estimates CSR strategies using specific leaf area (SLA), leaf dry matter content (LDMC) and leaf area (LA) data, but these three traits can hardly characterise whole-plant responses to the environment individually. CSR strategies reflect tradeoffs among growth, survival and reproduction, at both leaf and whole-plant levels, thus integrating several functions. We hypothesised that CSR strategies and the three constituent traits would show independent plasticity patterns, and that CSR strategies would be more likely to show adaptive responses, i.e. to fit expected functional responses to environmental gradients. We compared phenotypic plasticity to drought in single traits (SLA, LDMC and LA) with the integrated plasticity of the resulting CSR strategy. The study species was the invasive plant Mesembryanthemum crystallinum, which is distributed in arid and semiarid Chile. We found that trait plasticity was rather idiosyncratic and contrary to what would be expected from a functional adjustment to drought: LDMC did not change (expected response: increase) and SLA increased (expected response: decrease). Conversely, plastic responses of CSR strategy and LA were consistent with functionally adaptive responses to drought in all populations: S-strategy increased, while C-strategy and LA decreased. We advocate the use of Grime's CSR theory as an integrative approach to further our understanding of adaptive plasticity in plants.
Adaptive plasticity to drought of Grime's CSR strategies
(2023/11/01) Escobedo Victor M.; Molina-Montenegro Marco A.; Salgado-Luarte Cristian; Stotz Gisela C.; Gianoli Ernesto
Grime's strategies (competitor, stress tolerator, ruderal; CSR) represent viable trait combinations with which species deal with environmental conditions. CSR strategies are broadly used to understand plant adaptation to the environment, yet their plastic responses have received little attention. A globally-calibrated tool (StrateFy) estimates CSR strategies using specific leaf area (SLA), leaf dry matter content (LDMC) and leaf area (LA) data, but these three traits can hardly characterise whole-plant responses to the environment individually. CSR strategies reflect tradeoffs among growth, survival and reproduction, at both leaf and whole-plant levels, thus integrating several functions. We hypothesised that CSR strategies and the three constituent traits would show independent plasticity patterns, and that CSR strategies would be more likely to show adaptive responses, i.e. to fit expected functional responses to environmental gradients. We compared phenotypic plasticity to drought in single traits (SLA, LDMC and LA) with the integrated plasticity of the resulting CSR strategy. The study species was the invasive plant Mesembryanthemum crystallinum, which is distributed in arid and semiarid Chile. We found that trait plasticity was rather idiosyncratic and contrary to what would be expected from a functional adjustment to drought: LDMC did not change (expected response: increase) and SLA increased (expected response: decrease). Conversely, plastic responses of CSR strategy and LA were consistent with functionally adaptive responses to drought in all populations: S-strategy increased, while C-strategy and LA decreased. We advocate the use of Grime's CSR theory as an integrative approach to further our understanding of adaptive plasticity in plants.
Álgebras y fibrados de Clifford con aplicaciones
(Universidad de La Serena, 2012) Notte-Cuello, Eduardo
ALMA FIR View of Ultra-high-redshift Galaxy Candidates at z ∼ 11-17: Blue Monsters or Low-z Red Interlopers?
(IOP Publishing Ltd, 2023/10/01) Fujimoto, Seiji, Finkelstein, Steven L., Burgarella, Denis, Carilli, Chris L., Buat, Veronique, Casey, Caitlin M., Ciesla, Laure, Tacchella, Sandro, Zavala, Jorge A., Brammer, Gabriel, Fudamoto, Yoshinobu, Ouchi, Masami, Valentino, Francesco, Cooper, M. C., Dickinson, Mark, Franco, Maximilien, Giavalisco, Mauro, Hutchison, Taylor A., Kartaltepe, Jeyhan S., Koekemoer, Anton M., Kojima, Takashi, Larson, Rebecca L., Murphy, E. J., Papovich, Casey, Perez-Gonzalez, Pablo G., Somerville, Rachel S., Yoon, Ilsang, Wilkins, Stephen M., Akins, Hollis, Amorin, Ricardo O., Haro, Pablo Arrabal, Bagley, Micaela B., Chworowsky, Katherine, Cleri, Nikko J., Cooper, Olivia R., Costantin, Luca, Daddi, Emanuele, Ferguson, Henry C., Grogin, Norman A., Jimenez-Andrade, E. F., Juneau, Stephanie, Kirkpatrick, Allison, Kocevski, Dale D., Le Bail, Aurelien, Long, Arianna, Lucas, Ray A., Magnelli, Benjamin, McKinney, Jed, Rose, Caitlin, Seille, Lise-Marie, Simons, Raymond C., Weiner, Benjamin J., Yung, L. Y. Aaron
We present Atacama Large Millimeter/submillimeter Array (ALMA) Band 7 observations of a remarkably bright galaxy candidate at (M-UV = -21.6), S5-z17-1, identified in James Webb Space Telescope (JWST) Early Release Observation data of Stephen's Quintet. We do not detect the dust continuum at 866 mu m, ruling out the possibility that S5-z17-1 is a low-z dusty starburst with a star formation rate of greater than or similar to 30 M-circle dot yr(-1). We detect a 5.1s line feature at 338.726 +/- 0.007 GHz exactly coinciding with the JWST source position, with a 2% likelihood of the signal being spurious. The most likely line identification would be [O III]52 mu m at z = 16.01 or [C II]158 mu m at z = 4.61, whose line luminosities do not violate the nondetection of the dust continuum in both cases. Together with three other z greater than or similar to 11-13 candidate galaxies recently observed with ALMA, we conduct a joint ALMA and JWST spectral energy distribution (SED) analysis and find that the high-z solution at z similar to 11-17 is favored in every candidate as a very blue (UV continuum slope of similar or equal to-2.3) and luminous (M-UV similar or equal to [ - 24:-21]) system. Still, we find in several candidates that reasonable SED fits (Delta chi(2) less than or similar to 4) are reproduced by type II quasar and/or quiescent galaxy templates with strong emission lines at z similar to 3-5, where such populations predicted from their luminosity functions and EW([O iii]+H beta) distributions are abundant in survey volumes used for the identification of the z similar to 11-17 candidates. While these recent ALMA observation results have strengthened the likelihood of the high-z solutions, lower-z possibilities are not completely ruled out in several of the z similar to 11-17 candidates, indicating the need to consider the relative surface densities of the lower-z contaminants in the ultra-high-z galaxy search.
ALUMINUM RECOVERY FROM MINE TAILINGS, APPLYING INNOVATIVE CHEMICAL AND BIOLOGICAL PROCESSES
(EXECUTIVE BUSINESS SCH-EXEBS, 01-06-2023) Zamarreno-Bastias Ricardo, Espinoza-Barrera Javiera
An investigation was carried out, at the chemical -metallurgical laboratory level, evaluating two methods in the recovery of aluminum, present in an abandoned mining tailing. In order to find a new source of recovery for this element. Aluminum is found in the form of aluminosilicates in the tailings. Two methods were used, a biological process and a chemical one. In the biological one, bioleaching was carried out with cultivated Aspergillus niger fungi, which produces organic acids, which can extract aluminum from the tailings. The chemical method consisted of leaching with two organic acids, citric acid and oxalic acid with the addition of oxidizing agents such as hydrogen peroxide and a strong base. According to the results, the methods that had the highest extraction were chemical, specifically leaching with the mixture of oxalic acid and hydrogen peroxide. In the case of bioleaching, no significant results were obtained in the extraction of aluminum.
An ever-present Gaia snail shell triggered by a dark matter wake
(OXFORD UNIV PRESS, 2023/07/04) Grand, Robert J. J., Pakmor, Ruediger, Fragkoudi, Francesca, Gomez, Facundo A., Trick, Wilma, Simpson, Christine M., van de Voort, Freeke, Bieri, Rebekka
We utilize a novel numerical technique to model star formation in cosmological simulations of galaxy formation - called SUPERSTARS - to simulate a Milky Way-like galaxy with greater than or similar to 10(8) star particles to study the formation and evolution of out-of-equilibrium stellar disc structures in a full cosmological setting. In the plane defined by the coordinate and velocity perpendicular to the mid-plane [vertical phase space, (Z, V-Z)], stars in solar- like volumes at late times exhibit clear spirals qualitatively similar in shape and amplitude to the Gaia 'snail shell' phase spiral. We show that the phase spiral forms at a lookback time of similar to 6 Gyr during the pericentric passage of an similar to 10(10) M-circle dot satellite on a polar orbit. This satellite stimulates the formation of a resonant wake in the dark matter halo while losing mass at a rate of similar to 0.5-1 dex per orbit loop. The peak magnitude of the wake-induced gravitational torque at the solar radius is similar to 8 times that from the satellite, and triggers the formation of a disc warp that wraps up into a vertical phase spiral over time. As the wake decays, the phase spiral propagates several gigayears to present day and can be described as `ever-present' once stable disc evolution is established. These results suggest an alternative scenario to explain the Gaia phase spiral, which does not rely on a perturbation from bar buckling or a recent direct hit from a satellite.
An exotic plant species indirectly facilitates a secondary exotic plant through increased soil salinity
(SPRINGER, 2023/08/01) de la Cruz Henry J. J., Salgado-Luarte Cristian, Stotz Gisela C. C., Gianoli Ernesto
Indirect facilitation among exotic species may promote their establishment on ecosystems, causing biodiversity losses. However, few experimental studies have identified the mechanisms underlying the indirect facilitation among exotic species. In central-northern Chile, Mesembryanthemum crystallinum (Aizoaceae) is an exotic halophyte that increases soil salinity, while M. nodiflorum is another exotic halophyte -currently less dominant- that often co-occurs with M. crystallinum. In this study, we evaluated the indirect facilitation of M. nodiflorum by M. crystallinum which was mediated by the suppression of salt-susceptible native competitors via increased soil salinity. We further determined the relationship between salt-tolerance traits and the outcome of competitive interactions in saline soil. We included two native Asteraceae plants co-occurring with these Mesembryanthemum species: the -highly probable- salt-susceptible Helenium urmenetae and the salt-tolerant Amblyopappus pusillus. We combined field co-occurrence surveys with greenhouse germination and competition experiments. The Mesembryanthemum species tended to co-occur, which suggests facilitation. Further, the salinity level found under M. crystallinum significantly decreased germination and performance of H. urmenetae, but not of M. nodiflorum and A. pusillus. Accordingly, when in competition, the increased salinity counteracted the negative effect of H. urmenetae on M. nodiflorum biomass, giving M. nodiflorum a competitive advantage. These patterns were associated with decreased specific leaf area and crassulacean acid metabolism expression in M. nodiflorum. In contrast, A. pusillus and M. nodiflorum maintained a neutral interaction regardless of salinity. Overall, our results suggest that M. crystallinum, by increasing soil salinity, may reduce the performance of salt-susceptible competitors, indirectly facilitating the establishment of M. nodiflorum.
An exotic plant species indirectly facilitates a secondary exotic plant through increased soil salinity
(2023/08/01) de la Cruz Henry J. J.; Salgado-Luarte Cristian; Stotz Gisela C. C.; Gianoli Ernesto
Indirect facilitation among exotic species may promote their establishment on ecosystems, causing biodiversity losses. However, few experimental studies have identified the mechanisms underlying the indirect facilitation among exotic species. In central-northern Chile, Mesembryanthemum crystallinum (Aizoaceae) is an exotic halophyte that increases soil salinity, while M. nodiflorum is another exotic halophyte -currently less dominant- that often co-occurs with M. crystallinum. In this study, we evaluated the indirect facilitation of M. nodiflorum by M. crystallinum which was mediated by the suppression of salt-susceptible native competitors via increased soil salinity. We further determined the relationship between salt-tolerance traits and the outcome of competitive interactions in saline soil. We included two native Asteraceae plants co-occurring with these Mesembryanthemum species: the -highly probable- salt-susceptible Helenium urmenetae and the salt-tolerant Amblyopappus pusillus. We combined field co-occurrence surveys with greenhouse germination and competition experiments. The Mesembryanthemum species tended to co-occur, which suggests facilitation. Further, the salinity level found under M. crystallinum significantly decreased germination and performance of H. urmenetae, but not of M. nodiflorum and A. pusillus. Accordingly, when in competition, the increased salinity counteracted the negative effect of H. urmenetae on M. nodiflorum biomass, giving M. nodiflorum a competitive advantage. These patterns were associated with decreased specific leaf area and crassulacean acid metabolism expression in M. nodiflorum. In contrast, A. pusillus and M. nodiflorum maintained a neutral interaction regardless of salinity. Overall, our results suggest that M. crystallinum, by increasing soil salinity, may reduce the performance of salt-susceptible competitors, indirectly facilitating the establishment of M. nodiflorum.
Analytical Hierarchical Process to Establish the Criteria for Choosing Explosives Suppliers in Small and Medium Mining Companies
(MDPI, 01-09-2023) Ramirez Olivares Edison, Castillo-Vergara Mauricio
Mining plays a pivotal role in economies worldwide, contributing to employment, infrastructure, and the supply of essential raw materials. Chile's global mining powerhouse, particularly in copper production, exemplifies this industry's economic significance. The supplier selection process in the mining industry, a complex and multifaceted task, is explored in detail, specifically focusing on explosives procurement, a critical component for mineral extraction. The paper underscores the importance of informed supplier selection decisions, especially for SMEs, which often need more resources and capabilities for efficient management. To address these challenges, the study proposes applying the Analytic Hierarchical Process (AHP), a multi-criteria decision-making methodology, to identify and prioritize the criteria and sub-criteria pertinent to choosing explosives suppliers. A case study in the Coquimbo Region, Chile, involving SMEs in the mining sector is the empirical foundation for this research. Our research highlights that the foremost criterion for SMEs in the Coquimbo Region's mining sector is relationship with the environment and communities. This reflects the national context of mining community tensions and the rising environmental standards and social expectations, which can profoundly impact mining operations. Quality of products and services is the second most crucial criterion, underscoring SMEs' drive to enhance productivity and efficiency. Contractual compliance follows closely, signifying the integration of SMEs into broader social and environmental sustainability efforts. Conversely, innovation ranks as the least relevant criterion, indicating that SMEs prioritize traditional processes due to limited resources and cost constraints. These insights are valuable for mining supplier company managers, emphasizing the need for sustainability, corporate social responsibility, and management control systems.