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The Eighteenth Data Release of the Sloan Digital Sky Surveys: Targeting and First Spectra from SDSS-V
(IOP Publishing Ltd, 2023/08/01) Almeida, Andres, Anderson, Scott F., Argudo-Fernandez, Maria, Badenes, Carles, Barger, Kat, Barrera-Ballesteros, Jorge K., Bender, Chad F., Benitez, Erika, Besser, Felipe, Bird, Jonathan C., Bizyaev, Dmitry, Blanton, Michael R., Bochanski, John, Bovy, Jo, Brandt, William Nielsen, Brownstein, Joel R., Buchner, Johannes, Bulbul, Esra, Burchett, Joseph N., Diaz, Mariana Cano, Carlberg, Joleen K., Casey, Andrew R., Chandra, Vedant, Cherinka, Brian, Chiappini, Cristina, Coker, Abigail A., Comparat, Johan, Conroy, Charlie, Contardo, Gabriella, Cortes, Arlin, Covey, Kevin, Crane, Jeffrey D., Cunha, Katia, Dabbieri, Collin, Davidson, James W., Davis, Megan C., de Andrade Queiroz, Anna Barbara, De Lee, Nathan, Mendez Delgado, Jose Eduardo, Demasi, Sebastian, Di Mille, Francesco, Donor, John, Dow, Peter, Dwelly, Tom, Eracleous, Mike, Eriksen, Jamey, Fan, Xiaohui, Farr, Emily, Frederick, Sara, Fries, Logan, Frinchaboy, Peter, Gaensicke, Boris T., Ge, Junqiang, Gonzalez Avila, Consuelo, Grabowski, Katie, Grier, Catherine, Guiglion, Guillaume, Gupta, Pramod, Hall, Patrick, Hawkins, Keith, Hayes, Christian R., Hermes, J. J., Hernandez-Garcia, Lorena, Hogg, David W., Holtzman, Jon A., Ibarra-Medel, Hector Javier, Ji, Alexander, Jofre, Paula, Johnson, Jennifer A., Jones, Amy M., Kinemuchi, Karen, Kluge, Matthias, Koekemoer, Anton, Kollmeier, Juna A., Kounkel, Marina, Krishnarao, Dhanesh, Krumpe, Mirko, Lacerna, Ivan, Lago, Paulo Jakson Assuncao, Laporte, Chervin, Liu, Chao, Liu, Ang, Liu, Xin, Lopes, Alexandre Roman, Macktoobian, Matin, Majewski, Steven R., Malanushenko, Viktor, Maoz, Dan, Masseron, Thomas, Masters, Karen L., Matijevic, Gal, McBride, Aidan, Medan, Ilija, Merloni, Andrea, Morrison, Sean, Myers, Natalie, Meszaros, Szabolcs, Negrete, C. Alenka, Nidever, David L., Nitschelm, Christian, Oravetz, Daniel, Oravetz, Audrey, Pan, Kaike, Peng, Yingjie, Pinsonneault, Marc H., Pogge, Rick, Qiu, Dan, Ramirez, Solange V., Rix, Hans-Walter, Rosso, Daniela Fernandez, Runnoe, Jessie, Salvato, Mara, Sanchez, Sebastian F., Santana, Felipe A., Saydjari, Andrew, Sayres, Conor, Schlaufman, Kevin C., Schneider, Donald P., Schwope, Axel, Serna, Javier, Shen, Yue, Sobeck, Jennifer, Song, Ying-Yi, Souto, Diogo, Spoo, Taylor, Stassun, Keivan G., Steinmetz, Matthias, Straumit, Ilya, Stringfellow, Guy, Sanchez-Gallego, Jose, Taghizadeh-Popp, Manuchehr, Tayar, Jamie, Thakar, Ani, Tissera, Patricia B., Tkachenko, Andrew, Toledo, Hector Hernandez, Trakhtenbrot, Benny, Fernandez-Trincado, Jose G., Troup, Nicholas, Trump, Jonathan R., Tuttle, Sarah, Ulloa, Natalie, Vazquez-Mata, Jose Antonio, Alfaro, Pablo Vera, Villanova, Sandro, Wachter, Stefanie, Weijmans, Anne-Marie, Wheeler, Adam, Wilson, John, Wojno, Leigh, Wolf, Julien, Xue, Xiang-Xiang, Ybarra, Jason E., Zari, Eleonora, Zasowski, Gail
The eighteenth data release (DR18) of the Sloan Digital Sky Survey (SDSS) is the first one for SDSS-V, the fifth generation of the survey. SDSS-V comprises three primary scientific programs or Mappers: the Milky Way Mapper (MWM), the Black Hole Mapper (BHM), and the Local Volume Mapper. This data release contains extensive targeting information for the two multiobject spectroscopy programs (MWM and BHM), including input catalogs and selection functions for their numerous scientific objectives. We describe the production of the targeting databases and their calibration and scientifically focused components. DR18 also includes & SIM,25,000 new SDSS spectra and supplemental information for X-ray sources identified by eROSITA in its eFEDS field. We present updates to some of the SDSS software pipelines and preview changes anticipated for DR19. We also describe three value-added catalogs (VACs) based on SDSS-IV data that have been published since DR17, and one VAC based on the SDSS-V data in the eFEDS field.
Dusty Starbursts Masquerading as Ultra-high Redshift Galaxies in JWST CEERS Observations
(IOP Publishing Ltd, 2023/02/01) Zavala, Jorge A., Buat, Veronique, Casey, Caitlin M., Finkelstein, Steven L., Burgarella, Denis, Bagley, Micaela B., Ciesla, Laure, Daddi, Emanuele, Dickinson, Mark, Ferguson, Henry C., Franco, Maximilien, Jimenez-Andrade, E. F., Kartaltepe, Jeyhan S., Koekemoer, Anton M., Le Bail, Aurelien, Murphy, E. J., Papovich, Casey, Tacchella, Sandro, Wilkins, Stephen M., Aretxaga, Itziar, Behroozi, Peter, Champagne, Jaclyn B., Fontana, Adriano, Giavalisco, Mauro, Grazian, Andrea, Grogin, Norman A., Kewley, Lisa J., Kocevski, Dale D., Kirkpatrick, Allison, Lotz, Jennifer M., Pentericci, Laura, Perez-Gonzalez, Pablo G., Pirzkal, Nor, Ravindranath, Swara, Somerville, Rachel S., Trump, Jonathan R., Yang, Guang, Yung, L. Y. Aaron, Almaini, Omar, Amorin, Ricardo O., Annunziatella, Marianna, Haro, Pablo Arrabal, Backhaus, Bren E., Barro, Guillermo, Bell, Eric F., Bhatawdekar, Rachana, Bisigello, Laura, Buitrago, Fernando, Calabro, Antonello, Castellano, Marco, Ortiz, Oscar A. Chavez, Chworowsky, Katherine, Cleri, Nikko J., Cohen, Seth H., Cole, Justin W., Cooke, Kevin C., Cooper, M. C., Cooray, Asantha R., Costantin, Luca, Cox, Isabella G., Croton, Darren, Dave, Romeel, de la Vega, Alexander, Dekel, Avishai, Elbaz, David, Estrada-Carpenter, Vicente, Fernandez, Vital, Finkelstein, Keely D., Freundlich, Jonathan, Fujimoto, Seiji, Garcia-Argumanez, Angela, Gardner, Jonathan P., Gawiser, Eric, Gomez-Guijarro, Carlos, Guo, Yuchen, Hamilton, Timothy S., Hathi, Nimish P., Holwerda, Benne W., Hirschmann, Michaela, Huertas-Company, Marc, Hutchison, Taylor A., Iyer, Kartheik G., Jaskot, Anne E., Jha, Saurabh W., Jogee, Shardha, Juneau, Stephanie, Jung, Intae, Kassin, Susan A., Kurczynski, Peter, Larson, Rebecca L., Leung, Gene C. K., Long, Arianna S., Lucas, Ray A., Magnelli, Benjamin, Mantha, Kameswara Bharadwaj, Matharu, Jasleen, McGrath, Elizabeth J., McIntosh, Daniel H., Medrano, Aubrey, Merlin, Emiliano, Mobasher, Bahram, Morales, Alexa M., Newman, Jeffrey A., Nicholls, David C., Pandya, Viraj, Rafelski, Marc, Ronayne, Kaila, Rose, Caitlin, Ryan, Russell E., Santini, Paola, Seille, Lise-Marie, Shah, Ekta A., Shen, Lu, Simons, Raymond C., Snyder, Gregory F., Stanway, Elizabeth R., Straughn, Amber N., Teplitz, Harry, I, Vanderhoof, Brittany N., Vega-Ferrero, Jesus, Wang, Weichen, Weiner, Benjamin J., Willmer, Christopher N. A., Wuyts, Stijn
Lyman-break galaxy (LBG) candidates at z greater than or similar to 10 are rapidly being identified in James Webb Space Telescope (JWST)/NIRCam observations. Due to the (redshifted) break produced by neutral hydrogen absorption of rest-frame UV photons, these sources are expected to drop out in the bluer filters while being well detected in redder filters. However, here we show that dust-enshrouded star-forming galaxies at lower redshifts (z less than or similar to 7) may also mimic the near-infrared (near-IR) colors of z > 10 LBGs, representing potential contaminants in LBG candidate samples. First, we analyze CEERS-DSFG-1, a NIRCam dropout undetected in the F115W and F150W filters but detected at longer wavelengths. Combining the JWST data with (sub)millimeter constraints, including deep NOEMA interferometric observations, we show that this source is a dusty star-forming galaxy (DSFG) at z approximate to 5.1. We also present a tentative 2.6 sigma SCUBA-2 detection at 850 mu m around a recently identified z approximate to 16 LBG candidate in the same field and show that, if the emission is real and associated with this candidate, the available photometry is consistent with a z similar to 5 dusty galaxy with strong nebular emission lines despite its blue near-IR colors. Further observations on this candidate are imperative to mitigate the low confidence of this tentative submillimeter emission and its positional uncertainty. Our analysis shows that robust (sub)millimeter detections of NIRCam dropout galaxies likely imply z similar to 4-6 redshift solutions, where the observed near-IR break would be the result of a strong rest-frame optical Balmer break combined with high dust attenuation and strong nebular line emission, rather than the rest-frame UV Lyman break. This provides evidence that DSFGs may contaminate searches for ultra-high redshift LBG candidates from JWST observations.
Reference frames and black hole thermodynamics
(IOP Publishing Ltd, 2023/12/01) Fiorini, Franco, Gonzalez, P. A., Vasquez, Yerko
In the context of the absolute parallelism formulation of General Relativity, and because of the fact that the scalar curvature can be written in purely torsional terms, it was known for a long time that a surface term based solely on the torsion tensor appears in the action. It was subsequently suggested that this term might play the role of the Gibbons -Hawking-York boundary term which, in turn, is associated to the free energy in the path integral approach, and then, to the black hole entropy by standard thermodynamic arguments. We show that the identification of the two boundary terms is rather incomplete, and that it strongly depends on the choice of the tetrad (frame) field used to reproduce a given metric. By considering variations of the tetrad field not necessarily subjected to Dirichlet-like conditions on the boundary surface, we find a class of frames adapted to the Schwarzschild spacetime in which the Gibbons-Hawking-York/torsion link is actually established, and conducing to the right black hole entropy without the need of any background subtraction. Remarkably, these frames are also responsible for the correct value of the gravitational energy as computed from the teleparallel energy-momentum pseudo-current.
Identification of Galaxy-Galaxy Strong Lens Candidates in the DECam Local Volume Exploration Survey Using Machine Learning
(IOP Publishing Ltd, 2023/09/01) Zaborowski, E. A., Drlica-Wagner, A., Ashmead, F., Wu, J. F., Morgan, R., Bom, C. R., Shajib, A. J., Birrer, S., Cerny, W., Buckley-Geer, E. J., Mutlu-Pakdil, B., Ferguson, P. S., Glazebrook, K., Lozano, S. J. Gonzalez, Gordon, Y., Martinez, M., Manwadkar, V., O'Donnell, J., Poh, J., Riley, A., Sakowska, J. D., Santana-Silva, L., Santiago, B. X., Sluse, D., Tan, C. Y., Tollerud, E. J., Verma, A., Carballo-Bello, J. A., Choi, Y., James, D. J., Kuropatkin, N., Martinez-Vazquez, C. E., Nidever, D. L., Castellon, J. L. Nilo, Noel, N. E. D., Olsen, K. A. G., Pace, A. B., Mau, S., Yanny, B., Zenteno, A., Abbott, T. M. C., Aguena, M., Alves, O., Andrade-Oliveira, F., Bocquet, S., Brooks, D., Burke, D. L., Carnero Rosell, A., Carrasco Kind, M., Carretero, J., Castander, F. J., Conselice, C. J., Costanzi, M., Pereira, M. E. S., De Vicente, J., Desai, S., Dietrich, J. P., Doel, P., Everett, S., Ferrero, I., Flaugher, B., Friedel, D., Frieman, J., Garcia-Bellido, J., Gruen, D., Gruendl, R. A., Gutierrez, G., Hinton, S. R., Hollowood, D. L., Honscheid, K., Kuehn, K., Lin, H., Marshall, J. L., Melchior, P., Mena-Fernandez, J., Menanteau, F., Miquel, R., Palmese, A., Paz-Chinchon, F., Pieres, A., Malagon, A. A. Plazas, Prat, J., Rodriguez-Monroy, M., Romer, A. K., Sanchez, E., Scarpine, V., Sevilla-Noarbe, I, Smith, M., Suchyta, E., To, C., Weaverdyck, N.
We perform a search for galaxy-galaxy strong lens systems using a convolutional neural network (CNN) applied to imaging data from the first public data release of the DECam Local Volume Exploration Survey, which contains similar to 520 million astronomical sources covering similar to 4000 deg2 of the southern sky to a 5 sigma point-source depth of g = 24.3, r = 23.9, i = 23.3, and z = 22.8 mag. Following the methodology of similar searches using Dark Energy Camera data, we apply color and magnitude cuts to select a catalog of similar to 11 million extended astronomical sources. After scoring with our CNN, the highest-scoring 50,000 images were visually inspected and assigned a score on a scale from 0 (not a lens) to 3 (very probable lens). We present a list of 581 strong lens candidates, 562 of which are previously unreported. We categorize our candidates using their human-assigned scores, resulting in 55 Grade A candidates, 149 Grade B candidates, and 377 Grade C candidates. We additionally highlight eight potential quadruply lensed quasars from this sample. Due to the location of our search footprint in the northern Galactic cap (b > 10 deg) and southern celestial hemisphere (decl. < 0 deg), our candidate list has little overlap with other existing ground-based searches. Where our search footprint does overlap with other searches, we find a significant number of high-quality candidates that were previously unidentified, indicating a degree of orthogonality in our methodology. We report properties of our candidates including apparent magnitude and Einstein radius estimated from the image separation.
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.
Spectroscopic Confirmation of CEERS NIRCam-selected Galaxies at z ≃ 8-10
(IOP Publishing Ltd, 2023/07/01) Haro, Pablo Arrabal, Dickinson, Mark, Finkelstein, Steven L., Fujimoto, Seiji, Fernandez, Vital, Kartaltepe, Jeyhan S., Jung, Intae, Cole, Justin W., Burgarella, Denis, Chworowsky, Katherine, Hutchison, Taylor A., Morales, Alexa M., Papovich, Casey, Simons, Raymond C., Amorin, Ricardo O., Backhaus, Bren E., Bagley, Micaela B., Bisigello, Laura, Calabro, Antonello, Castellano, Marco, Cleri, Nikko J., Dave, Romeel, Dekel, Avishai, Ferguson, Henry C., Fontana, Adriano, Gawiser, Eric, Giavalisco, Mauro, Harish, Santosh, Hathi, Nimish P., Hirschmann, Michaela, Holwerda, Benne W., Huertas-Company, Marc, Koekemoer, Anton M., Larson, Rebecca L., Lucas, Ray A., Mobasher, Bahram, Perez-Gonzalez, Pablo G., Pirzkal, Nor, Rose, Caitlin, Santini, Paola, Trump, Jonathan R., de la Vega, Alexander, Wang, Xin, Weiner, Benjamin J., Wilkins, Stephen M., Yang, Guang, Yung, L. Y. Aaron, Zavala, Jorge A.
We present JWST/NIRSpec prism spectroscopy of seven galaxies selected from Cosmic Evolution Early Release Science (CEERS) survey NIRCam imaging with photometric redshifts z(phot) > 8. We measure emission line redshifts of z = 7.65 and 8.64 for two galaxies. For two other sources without securely detected emission lines we measure = z 9.77(-0.29)(+0.37) and 10.01 (+0.14)(-0.19) by fitting model spectral templates to the prism data, from which we detect continuum breaks consistent with Ly alpha opacity from a mostly neutral intergalactic medium. The presence of strong breaks and the absence of strong emission lines give high confidence that these two galaxies have redshifts z > 9.6, but the redshift values derived from the breaks alone have large uncertainties given the low spectral resolution and relatively low S/N of the CEERS NIRSpec prism data. The two z similar to 10 sources observed are relatively luminous (MUV < -20), with blue continua (-2.3 less than or similar to ss less than or similar to -1.9) and low dust attenuation ( A similar or equal to 0.15(- 0.1)(+ 0.3)), and at least one of them has a high stellar mass for a galaxy at that redshift ( log M-* M-circle dot similar or equal to 9.3(-0.30)(+0.2) ). Considered together with spectroscopic observations of other CEERS NIRCam-selected high-z galaxy candidates in the literature, we find a high rate of redshift confirmation and low rate of confirmed interlopers (8%). Ten out of 35 z > 8 candidates with CEERS NIRSpec spectroscopy do not have secure redshifts, but the absence of emission lines in their spectra is consistent with redshifts z > 9.6. We find that z > 8 photometric redshifts are generally in agreement (within their uncertainties) with the spectroscopic values, but also that the photometric redshifts tend to be slightly overestimated ( = 0.45 +/- 0.11), suggesting that current templates do not fully describe the spectra of veryhigh-z sources. Overall, the spectroscopy solidifies photometric redshift evidence for a high spatial density of bright galaxies at z > 8 compared to theoretical model predictions, and further disfavors an accelerated decline in the integrated UV luminosity density at z > 8.
CEERS Key Paper. III. The Diversity of Galaxy Structure and Morphology at z=3-9 with JWST
(IOP Publishing Ltd, 2023/03/01) Kartaltepe, Jeyhan S., Rose, Caitlin, Vanderhoof, Brittany N., McGrath, Elizabeth J., Costantin, Luca, Cox, Isabella G., Yung, L. Y. Aaron, Kocevski, Dale D., Wuyts, Stijn, Ferguson, Henry C., Bagley, Micaela B., Finkelstein, Steven L., Amorin, Ricardo O., Andrews, Brett H., Haro, Pablo Arrabal, Backhaus, Bren E., Behroozi, Peter, Bisigello, Laura, Calabro, Antonello, Casey, Caitlin M., Coogan, Rosemary T., Cooper, M. C., Croton, Darren, de la Vega, Alexander, Dickinson, Mark, Fontana, Adriano, Franco, Maximilien, Grazian, Andrea, Grogin, Norman A., Hathi, Nimish P., Holwerda, Benne W., Huertas-Company, Marc, Iyer, Kartheik G., Jogee, Shardha, Jung, Intae, Kewley, Lisa J., Kirkpatrick, Allison, Koekemoer, Anton M., Liu, James, Lotz, Jennifer M., Lucas, Ray A., Newman, Jeffrey A., Pacifici, Camilla, Pandya, Viraj, Papovich, Casey, Pentericci, Laura, Perez-Gonzalez, Pablo G., Petersen, Jayse, Pirzkal, Nor, Rafelski, Marc, Ravindranath, Swara, Simons, Raymond C., Snyder, Gregory F., Somerville, Rachel S., Stanway, Elizabeth R., Straughn, Amber N., Tacchella, Sandro, Trump, Jonathan R., Vega-Ferrero, Jesus, Wilkins, Stephen M., Yang, Guang, Zavala, Jorge A.
We present a comprehensive analysis of the evolution of the morphological and structural properties of a large sample of galaxies at z = 3-9 using early James Webb Space Telescope (JWST) CEERS NIRCam observations. Our sample consists of 850 galaxies at z > 3 detected in both Hubble Space Telescope (HST)/WFC3 and CEERS JWST/NIRCam images, enabling a comparison of HST and JWST morphologies. We conduct a set of visual classifications, with each galaxy in the sample classified three times. We also measure quantitative morphologies across all NIRCam filters. We find that galaxies at z > 3 have a wide diversity of morphologies. Galaxies with disks make up 60% of galaxies at z = 3, and this fraction drops to similar to 30% at z = 6-9, while galaxies with spheroids make up similar to 30%-40% across the redshift range, and pure spheroids with no evidence for disks or irregular features make up similar to 20%. The fraction of galaxies with irregular features is roughly constant at all redshifts (similar to 40%-50%), while those that are purely irregular increases from similar to 12% to similar to 20% at z > 4.5. We note that these are apparent fractions, as many observational effects impact the visibility of morphological features at high redshift. On average, Spheroid-only galaxies have a higher Sersic index, smaller size, and higher axis ratio than disk or irregular galaxies. Across all redshifts, smaller spheroid and disk galaxies tend to be rounder. Overall, these trends suggest that galaxies with established disks and spheroids exist across the full redshift range of this study, and further work with large samples at higher redshift is needed to quantify when these features first formed.
Clash of Titans: the impact of cluster mergers in the galaxy cluster red sequence
(OXFORD UNIV PRESS, 2023/10/01) Aldas, Franklin, Zenteno, Alfredo, Gomez, Facundo A., Hernandez-Lang, Daniel, Carrasco, Eleazar R., Vega-Martinez, Cristian A., Castellon, J. L. Nilo
Merging of galaxy clusters are some of the most energetic events in the Universe, and they provide a unique environment to study galaxy evolution. We use a sample of 84 merging and relaxed SPT galaxy clusters candidates, observed with the Dark Energy Camera in the 0.11 < z < 0.88 redshift range, to build colour-magnitude diagrams to characterize the impact of cluster mergers on the galaxy population. We divided the sample between relaxed and disturbed, and in two redshifts bin at z = 0.55. When comparing the high-z to low-z clusters we find the high-z sample is richer in blue galaxies, independently of the cluster dynamical state. In the high-z bin, we find that disturbed clusters exhibit a larger scatter in the red sequence, with wider distribution and an excess of bluer galaxies compared to relaxed clusters, while in the low-z bin we find a complete agreement between the relaxed and disturbed clusters. Our results support the scenario in which massive cluster halos at z < 0.55 galaxies are quenched as satellites of another structure, i.e. outside the cluster, while at z >= 0.55 the quenching is dominated by in situ processes.
Hidden Little Monsters: Spectroscopic Identification of Low-mass, Broad-line AGNs at z > 5 with CEERS
(IOP Publishing Ltd, 2023/09/01) Kocevski, Dale D., Onoue, Masafusa, Inayoshi, Kohei, Trump, Jonathan R., Haro, Pablo Arrabal, Grazian, Andrea, Dickinson, Mark, Finkelstein, Steven L., Kartaltepe, Jeyhan S., Hirschmann, Michaela, Aird, James, Holwerda, Benne W., Fujimoto, Seiji, Juneau, Stephanie, Amorin, Ricardo O., Backhaus, Bren E., Bagley, Micaela B., Barro, Guillermo, Bell, Eric F., Bisigello, Laura, Calabro, Antonello, Cleri, Nikko J., Cooper, M. C., Ding, Xuheng, Grogin, Norman A., Ho, Luis C., Hutchison, Taylor A., Inoue, Akio K., Jiang, Linhua, Jones, Brenda, Koekemoer, Anton M., Li, Wenxiu, Li, Zhengrong, Mcgrath, Elizabeth J., Molina, Juan, Papovich, Casey, Perez-Gonzalez, Pablo G., Pirzkal, Nor, Wilkins, Stephen M., Yang, Guang, Yung, L. Y. Aaron
We report on the discovery of two low-luminosity, broad-line active galactic nuclei (AGNs) at z > 5 identified using JWST NIRSpec spectroscopy from the Cosmic Evolution Early Release Science (CEERS) survey. We detect broad H alpha emission in the spectra of both sources, with FWHM of 2060 +/- 290 km s-1 and 1800 +/- 200 km s-1, resulting in virial black hole (BH) masses that are 1-2 dex below those of existing samples of luminous quasars at z > 5. The first source, CEERS 2782 at z = 5.242, is 2-3 dex fainter than known quasars at similar redshifts and was previously identified as a candidate low-luminosity AGN based on its morphology and rest-frame optical spectral energy distribution (SED). We measure a BH mass of M BH = (1.3 +/- 0.4) x 107 M circle dot, confirming that this AGN is powered by the least massive BH known in the Universe at the end of cosmic reionization. The second source, CEERS 746 at z = 5.624, is inferred to be a heavily obscured, broad-line AGN caught in a transition phase between a dust-obscured starburst and an unobscured quasar. We estimate its BH mass to be in the range of M BH similar or equal to (0.9-4.7) x 107 M circle dot, depending on the level of dust obscuration assumed. We perform SED fitting to derive host stellar masses, M star, allowing us to place constraints on the BH-galaxy mass relationship in the lowest mass range yet probed in the early Universe. The M BH/M star ratio for CEERS 2782, in particular, is consistent with or higher than the empirical relationship seen in massive galaxies at z = 0. We examine the narrow emission line ratios of both sources and find that their location on the BPT and OHNO diagrams is consistent with model predictions for moderately low metallicity AGNs with Z/Z circle dot similar or equal to 0.2-0.4. The spectroscopic identification of low-luminosity, broad-line AGNs at z > 5 with M BH similar or equal to 107 M circle dot demonstrates the capability of JWST to push BH masses closer to the range predicted for the BH seed population and provides a unique opportunity to study the early stages of BH-galaxy assembly.
Hidden Little Monsters: Spectroscopic Identification of Low-mass, Broad-line AGNs at z> 5 with CEERS
(IOP Publishing Ltd, 2023/09/01) Kocevski, Dale D., Onoue, Masafusa, Inayoshi, Kohei, Trump, Jonathan R., Haro, Pablo Arrabal, Grazian, Andrea, Dickinson, Mark, Finkelstein, Steven L., Kartaltepe, Jeyhan S., Hirschmann, Michaela, Aird, James, Holwerda, Benne W., Fujimoto, Seiji, Juneau, Stephanie, Amorin, Ricardo O., Backhaus, Bren E., Bagley, Micaela B., Barro, Guillermo, Bell, Eric F., Bisigello, Laura, Calabro, Antonello, Cleri, Nikko J., Cooper, M. C., Ding, Xuheng, Grogin, Norman A., Ho, Luis C., Hutchison, Taylor A., Inoue, Akio K., Jiang, Linhua, Jones, Brenda, Koekemoer, Anton M., Li, Wenxiu, Li, Zhengrong, Mcgrath, Elizabeth J., Molina, Juan, Papovich, Casey, Perez-Gonzalez, Pablo G., Pirzkal, Nor, Wilkins, Stephen M., Yang, Guang, Yung, L. Y. Aaron
We report on the discovery of two low-luminosity, broad-line active galactic nuclei (AGNs) at z > 5 identified using JWST NIRSpec spectroscopy from the Cosmic Evolution Early Release Science (CEERS) survey. We detect broad Ha emission in the spectra of both sources, with FWHM of 2060 +/- 290 km s(-1) and 1800 +/- 200 km s(-1), resulting in virial black hole (BH) masses that are 1-2 dex below those of existing samples of luminous quasars at z > 5. The first source, CEERS 2782 at z = 5.242, is 2-3 dex fainter than known quasars at similar redshifts andwas previously identified as a candidate low-luminosity AGN based on its morphology and rest-frame optical spectral energy distribution (SED). We measure a BH mass of M-BH = (1.3 +/- 0.4) x 10(7)M(circle dot), confirming that this AGN is powered by the least massive BH known in the Universe at the end of cosmic reionization. The second source, CEERS 746 at z = 5.624, is inferred to be a heavily obscured, broad-line AGN caught in a transition phase between a dust-obscured starburst and an unobscured quasar. We estimate its BH mass to be in the range of MBH, (0.9-4.7) x 107Me, depending on the level of dust obscuration assumed. We perform SED fitting to derive host stellar masses, Ma, allowing us to place constraints on the BH-galaxy mass relationship in the lowest mass range yet probed in the early Universe. The M-BH/M-* ratio for CEERS 2782, in particular, is consistent with or higher than the empirical relationship seen in massive galaxies at z = 0. We examine the narrow emission line ratios of both sources and find that their location on the BPT and OHNO diagrams is consistent with model predictions for moderately low metallicity AGNs with Z/Ze(circle dot)similar or equal to 0.2-0.4. The spectroscopic identification of lowluminosity, broad-line AGNs at z > 5 with M-BH similar or equal to 10(7)M(circle dot) demonstrates the capability of JWST to push BH masses closer to the range predicted for the BH seed population and provides a unique opportunity to study the early stages of BH-galaxy assembly.
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.
The ALMA-ALPINE [CII] survey: Kennicutt-Schmidt relation in four massive main-sequence galaxies at z ∼ 4.5
(EDP SCIENCES S A, 2023/12/11) Bethermin, M., Accard, C., Guillaume, C., Dessauges-Zavadsky, M., Ibar, E., Cassata, P., Devereaux, T., Faisst, A., Freundlich, J., Jones, G. C., Kraljic, K., Algera, H., Amorin, R. O., Bardelli, S., Boquien, M., Buat, V., Donghia, E., Dubois, Y., Ferrara, A., Fudamoto, Y., Ginolfi, M., Guillard, P., Giavalisco, M., Gruppioni, C., Gururajan, G., Hathi, N., Hayward, C. C., Koekemoer, A. M., Lemaux, B. C., Magdis, G. E., Molina, J., Narayanan, D., Mayer, L., Pozzi, F., Rizzo, F., Romano, M., Tasca, L., Theule, P., Vergani, D., Vallini, L., Zamorani, G., Zanella, A., Zucca, E.
Aims. The Kennicutt-Schmidt (KS) relation between the gas and the star formation rate (SFR) surface density (Sigma(gas) - Sigma(SFR)) is essential to understand star formation processes in galaxies. To date, it has been measured up to z similar to 2.5 in main-sequence galaxies. In this Letter our aim is to put constraints at z similar to 4.5 using a sample of four massive main-sequence galaxies observed by ALMA at high resolution.Methods. We obtained similar to 0.3''-resolution [CII] and continuum maps of our objects, which we then converted into gas and obscured SFR surface density maps. In addition, we produced unobscured SFR surface density maps by convolving Hubble ancillary data in the rest-frame UV. We then derived the average Sigma(SFR) in various Sigma(gas) bins, and estimated the uncertainties using a Monte Carlo sampling.Results. Our galaxy sample follows the KS relation measured in main-sequence galaxies at lower redshift, and is slightly lower than the predictions from simulations. Our data points probe the high end both in terms of Sigma(gas) and Sigma(SFR), and gas depletion timescales (285-843 Myr) remain similar to z similar to 2 objects. However, three of our objects are clearly morphologically disturbed, and we could have expected shorter gas depletion timescales (less than or similar to 100 Myr) similar to merger-driven starbursts at lower redshifts. This suggests that the mechanisms triggering starbursts at high redshift may be different than in the low- and intermediate-z Universe.
The Physical Conditions of Emission-line Galaxies at Cosmic Dawn from JWST/NIRSpec Spectroscopy in the SMACS 0723 Early Release Observations
(IOP Publishing Ltd, 2023/03/01) Trump, Jonathan R., Haro, Pablo Arrabal, Simons, Raymond C., Backhaus, Bren E., Amorin, Ricardo O., Dickinson, Mark, Fernandez, Vital, Papovich, Casey, Nicholls, David C., Kewley, Lisa J., Brunker, Samantha W., Salzer, John J., Wilkins, Stephen M., Almaini, Omar, Bagley, Micaela B., Berg, Danielle A., Bhatawdekar, Rachana, Bisigello, Laura, Buat, Veronique, Burgarella, Denis, Calabro, Antonello, Casey, Caitlin M., Ciesla, Laure, Cleri, Nikko J., Cole, Justin W., Cooper, M. C., Cooray, Asantha R., Costantin, Luca, Croton, Darren, Ferguson, Henry C., Finkelstein, Steven L., Fujimoto, Seiji, Gardner, Jonathan P., Gawiser, Eric, Giavalisco, Mauro, Grazian, Andrea, Grogin, Norman A., Hathi, Nimish P., Hirschmann, Michaela, Holwerda, Benne W., Huertas-Company, Marc, Hutchison, Taylor A., Jogee, Shardha, Juneau, Stephanie, Jung, Intae, Kartaltepe, Jeyhan S., Kirkpatrick, Allison, Kocevski, Dale D., Koekemoer, Anton M., Lotz, Jennifer M., Lucas, Ray A., Magnelli, Benjamin, Matharu, Jasleen, Perez-Gonzalez, Pablo G., Pirzkal, Nor, Rafelski, Marc, Rose, Caitlin, Seille, Lise-Marie, Somerville, Rachel S., Straughn, Amber N., Tacchella, Sandro, Vanderhoof, Brittany N., Weiner, Benjamin J., Wuyts, Stijn, Aaron Yung, L. Y., Zavala, Jorge A.
We present rest-frame optical emission-line flux ratio measurements for five z > 5 galaxies observed by the James Webb Space Telescope Near-Infared Spectrograph (NIRSpec) in the SMACS 0723 Early Release Observations. We add several quality-control and post-processing steps to the NIRSpec pipeline reduction products in order to ensure reliable relative flux calibration of emission lines that are closely separated in wavelength, despite the uncertain absolute spectrophotometry of the current version of the reductions. Compared to z similar to 3 galaxies in the literature, the z > 5 galaxies have similar [O iii]lambda 5008/H beta ratios, similar [O iii]lambda 4364/H gamma ratios, and higher (similar to 0.5 dex) [Ne III]lambda 3870/[O II]lambda 3728 ratios. We compare the observations to MAPPINGS V photoionization models and find that the measured [Ne III]lambda 3870/[O II]lambda 3728, [O iii]lambda 4364/H gamma, and [O iii]lambda 5008/H beta emission-line ratios are consistent with an interstellar medium (ISM) that has very high ionization ( log(Q)?8-9 , units of cm s(-1)), low metallicity (Z/Z (?) ? 0.2), and very high pressure ( log(P/k)?8-9, units of cm(-3)). The combination of [O iii]lambda 4364/H gamma and [O iii]lambda(4960 + 5008)/H beta line ratios indicate very high electron temperatures of 4.1 < log(T-e/K) < 4.4, further implying metallicities of Z/Z(?)?0.2 with the application of low-redshift calibrations for T-e -based metallicities. These observations represent a tantalizing new view of the physical conditions of the ISM in galaxies at cosmic dawn.
CEERS Spectroscopic Confirmation of NIRCam-selected z ≳ 8 Galaxy Candidates with JWST/NIRSpec: Initial Characterization of Their Properties
(IOP Publishing Ltd, 2023/06/01) Fujimoto, Seiji, Haro, Pablo Arrabal, Dickinson, Mark, Finkelstein, Steven L., Kartaltepe, Jeyhan S., Larson, Rebecca L., Burgarella, Denis, Bagley, Micaela B., Behroozi, Peter, Chworowsky, Katherine, Hirschmann, Michaela, Trump, Jonathan R., Wilkins, Stephen M., Yung, L. Y. Aaron, Koekemoer, Anton M., Papovich, Casey, Pirzkal, Nor, Ferguson, Henry C., Fontana, Adriano, Grogin, Norman A., Grazian, Andrea, Kewley, Lisa J., Kocevski, Dale D., Lotz, Jennifer M., Pentericci, Laura, Ravindranath, Swara, Somerville, Rachel S., Wilkins, Stephen M., Amorin, Ricardo O., Backhaus, Bren E., Calabro, Antonello, Casey, Caitlin M., Cooper, M. C., Fernandez, Vital, Franco, Maximilien, Giavalisco, Mauro, Hathi, Nimish P., Harish, Santosh, Hutchison, Taylor A., Iyer, Kartheik G., Jung, Intae, Lucas, Ray A., Zavala, Jorge A.
We present JWST NIRSpec spectroscopy for 11 galaxy candidates with photometric redshifts of z similar or equal to 9 - 13 and M-UV is an element of [ -21, -18] newly identified in NIRCam images in the Cosmic Evolution Early Release Science Survey. We confirm emission line redshifts for 7 galaxies at z = 7.762-8.998 using spectra at similar to 1-5 mu m either with the NIRSpec prism or its three medium-resolution (R similar to 1000) gratings. For z similar or equal to 9 photometric candidates, we achieve a high confirmation rate of similar or equal to 90%, which validates the classical dropout selection from NIRCam photometry. No robust emission lines are identified in three galaxy candidates at z > 10, where the strong [O iii] and H beta lines would be redshifted beyond the wavelength range observed by NIRSpec, and the Ly alpha continuum break is not detected with the sensitivity of the current data. Compared with Hubble Space Telescope-selected bright galaxies (M-UV similar or equal to -22) that are similarly spectroscopically confirmed at z similar or equal to 8 - 9, these NIRCam-selected galaxies are characterized by lower star formation rates (SFRs, SFR similar or equal to 4 M-circle dot yr(-1)) and lower stellar masses (similar or equal to 10(8)M(circle dot)), but with higher specific SFR (similar or equal to 40 Gyr(-1)), higher [O iii]+H beta equivalent widths (similar or equal to 1100 angstrom), and elevated production efficiency of ionizing photons (log(xi(ion)/Hz erg(-1)) similar or equal to 25.8) induced by young stellar populations (<10 Myr) accounting for similar or equal to 20% of the galaxy mass, highlighting the key contribution of faint galaxies to cosmic reionization. Taking advantage of the homogeneous selection and sensitivity, we also investigate metallicity and ISM conditions with empirical calibrations using the [O iii](5008)/H beta ratio. We find that galaxies at z similar or equal to 8 - 9 have higher SFRs and lower metallicities than galaxies at similar stellar masses at z similar or equal to 2 - 6, which is generally consistent with the current galaxy formation and evolution models.
Pegasus IV: Discovery and Spectroscopic Confirmation of an Ultra-faint Dwarf Galaxy in the Constellation Pegasus
(IOP Publishing Ltd, 2023/01/01) Cerny, W., Simon, J. D., Li, T. S., Drlica-Wagner, A., Pace, A. B., Martinez-Vazquez, C. E., Riley, A. H., Mutlu-Pakdil, B., Mau, S., Ferguson, P. S., Erkal, D., Munoz, R. R., Bom, C. R., Carlin, J. L., Carollo, D., Choi, Y., Ji, A. P., Manwadkar, V., Martinez-Delgado, D., Miller, A. E., Noel, N. E. D., Sakowska, J. D., Sand, D. J., Stringfellow, G. S., Tollerud, E. J., Vivas, A. K., Carballo-Bello, J. A., Hernandez-Lang, D., James, D. J., Nidever, D. L., Castellon, J. L. Nilo, Olsen, K. A. G., Zenteno, A.
We report the discovery of Pegasus IV, an ultra-faint dwarf galaxy found in archival data from the Dark Energy Camera processed by the DECam Local Volume Exploration Survey. Pegasus IV is a compact, ultra-faint stellar system ( = -r(1/2) 41(-6)(+8) pc, M-V = -4.25 +/- 0.2 mag) located at a heliocentric distance of 90(-6)(+4) kpc. Based on spectra of seven nonvariable member stars observed with Magellan/IMACS, we confidently resolve Pegasus IV's velocity dispersion, measuring s = sigma(v) 3.3(-1.1)(+1.7) km s(-1) (after excluding three velocity outliers), this implies a mass-to-light ratio of M1/2LV ,(1/2)=167(-99)(+224) M-?/L-? for the system. From the five stars with the highest signal-to-noise spectra, we also measure a systemic metallicity of [Fe/H] = -2.63(-0.30)(+0.26) dex, making Pegasus IV one of the most metal-poor ultra-faint dwarfs. We tentatively resolve a nonzero metallicity dispersion for the system. These measurements provide strong evidence that Pegasus IV is a dark-matter-dominated dwarf galaxy, rather than a star cluster. We measure Pegasus IV's proper motion using data from Gaia Early Data Release 3, finding (mu(alpha*, mu delta)) = (0.33 +/- 0.07, -0.21 +/- 0.08) mas yr(-1). When combined with our measured systemic velocity, this proper motion suggests that Pegasus IV is on an elliptical, retrograde orbit, and is currently near its orbital apocenter. Lastly, we identify three potential RR Lyrae variable stars within Pegasus IV, including one candidate member located more than 10 half-light radii away from the system's centroid. The discovery of yet another ultra-faint dwarf galaxy strongly suggests that the census of Milky Way satellites is still incomplete, even within 100 kpc.
Rubin Observatory LSST Stars Milky Way and Local Volume Star Clusters Roadmap
(IOP Publishing Ltd, 2023/07/01) Usher, Christopher, Dage, Kristen C., Girardi, Leo, Barmby, Pauline, Bonatto, Charles J., Chies-Santos, Ana L., Clarkson, William I., Camus, Matias Gomez, Hartmann, Eduardo A., Ferguson, Annette M. N., Pieres, Adriano, Prisinzano, Loredana, Rhode, Katherine L., Michael Rich, R., Ripepi, Vincenzo, Santiago, Basilio, Stassun, Keivan G., Street, R. A., Szabo, Robert, Venuti, Laura, Zaggia, Simone, Canossa, Marco, Floriano, Pedro, Lopes, Pedro, Miranda, Nicole L., Oliveira, Raphael A. P., Reina-Campos, Marta, Roman-Lopes, A., Sobeck, Jennifer
The Vera C. Rubin Observatory will undertake the Legacy Survey of Space and Time, providing an unprecedented, volume-limited catalog of star clusters in the Southern Sky, including Galactic and extragalactic star clusters. The Star Clusters subgroup of the Stars, Milky Way and Local Volume Working Group has identified key areas where Rubin Observatory will enable significant progress in star cluster research. This roadmap represents our science cases and preparation for studies of all kinds of star clusters from the Milky Way out to distances of tens of megaparsecs.
Stellar Properties for a Comprehensive Collection of Star-forming Regions in the SDSS APOGEE-2 Survey
(IOP Publishing Ltd, 2023/02/01) Roman-Zuniga, Carlos G., Kounkel, Marina, Hernandez, Jesus, Pena Ramirez, Karla, Lopez-Valdivia, Ricardo, Covey, Kevin R., Stutz, Amelia M., Roman-Lopes, Alexandre, Campbell, Hunter, Khilfeh, Elliott, Tapia, Mauricio, Stringfellow, Guy S., Jose Downes, Juan, Stassun, Keivan G., Minniti, Dante, Bayo, Amelia, Kim, Jinyoung Serena, Suarez, Genaro, Ybarra, Jason E., Fernandez-Trincado, Jose G., Longa-Pena, Penelope, Ramirez-Preciado, Valeria, Serna, Javier, Lane, Richard R., Garcia-Hernandez, D. A., Beaton, Rachael L., Bizyaev, Dmitry, Pan, Kaike
The Sloan Digital Sky Survey IV APOGEE-2 primary science goal was to observe red giant stars throughout the Galaxy to study its dynamics, morphology, and chemical evolution. The APOGEE instrument, a high-resolution 300fiber H-band (1.55-1.71 mu m) spectrograph, is also ideal to study other stellar populations in the Galaxy, among which are a number of star-forming regions and young open clusters. We present the results of the determination of six stellar properties (Teff, log g, [Fe/H], L/L-circle dot, M/M-circle dot, and age) for a sample that is composed of 3360 young stars, of subsolar to supersolar types, in 16 Galactic star formation and young open cluster regions. Those sources were selected by using a clustering method that removes most of the field contamination. Samples were also refined by removing targets affected by various systematic effects of the parameter determination. The final samples are presented in a comprehensive catalog that includes all six estimated parameters. This overview study also includes parameter spatial distribution maps for all regions and Hertzsprung-Russell (log L/L-circle dot vs. T-eff) diagrams. This study serves as a guide for detailed studies on individual regions and paves the way for the future studies on the global properties of stars in the pre-main-sequence phase of stellar evolution using more robust samples.
CLASSY VII Lyα Profiles: The Structure and Kinematics of Neutral Gas and Implications for LyC Escape in Reionization-era Analogs
(IOP Publishing Ltd, 2023/10/01) Hu, Weida, Martin, Crystal L., Gronke, Max, Gazagnes, Simon, Hayes, Matthew, Chisholm, John, Heckman, Timothy, Mingozzi, Matilde, Roy, Namrata, Senchyna, Peter, Xu, Xinfeng, Berg, Danielle A., James, Bethan L., Stark, Daniel P., Arellano-Cordova, Karla Z., Henry, Alaina, Jaskot, Anne E., Kumari, Nimisha, Parker, Kaelee S., Scarlata, Claudia, Wofford, Aida, Amorin, Ricardo O., Leonhardes-Barboza, Naunet, Brinchmann, Jarle, Carr, Cody, Aloisi, Alessandra
Ly alpha line profiles are a powerful probe of interstellar medium (ISM) structure, outflow speed, and Lyman-continuum escape fraction. In this paper, we present the Ly alpha line profiles of the Cosmic Origins Spectrograph (COS) Legacy Archive Spectroscopic SurveY, a sample rich in spectroscopic analogs of reionization-era galaxies. A large fraction of the spectra show a complex profile, consisting of a double-peaked Ly alpha emission profile in the bottom of a damped, Ly alpha absorption trough. Such profiles reveal an inhomogeneous ISM. We successfully fit the damped Ly alpha absorption and the Ly alpha emission profiles separately, but with complementary covering factors, a surprising result because this approach requires no Ly alpha exchange between high-N-H I and low-N-H I paths. The combined distribution of column densities is qualitatively similar to the bimodal distributions observed in numerical simulations. We find an inverse relation between Ly alpha peak separation and the [O III]/[O II] flux ratio, confirming that the covering fraction of Lyman-continuum-thin sightlines increases as the Ly alpha peak separation decreases. We combine measurements of Ly alpha peak separation and Ly alpha red peak asymmetry in a diagnostic diagram, which identifies six Lyman-continuum leakers in the COS Legacy Archive Spectrocopy SurveY (CLASSY) sample. We find a strong correlation between the Ly alpha trough velocity and the outflow velocity measured from interstellar absorption lines. We argue that greater vignetting of the blueshifted Ly alpha peak, relative to the redshifted peak, is the source of the well-known discrepancy between shell-model parameters and directly measured outflow properties. The CLASSY sample illustrates how scattering of Ly alpha photons outside the spectroscopic aperture reshapes Ly alpha profiles because the distances to these compact starbursts span a large range.
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.
The Low-redshift Lyman Continuum Survey: Optically Thin and Thick Mg ii Lines as Probes of Lyman Continuum Escape
(IOP Publishing Ltd, 2023/02/01) Xu, Xinfeng, Henry, Alaina, Heckman, Timothy, Chisholm, John, Marques-Chaves, Rui, Leclercq, Floriane, Berg, Danielle A., Jaskot, Anne, Schaerer, Daniel, Worseck, Gabor, Amorin, Ricardo O., Atek, Hakim, Hayes, Matthew, Ji, Zhiyuan, Ostlin, Goran, Saldana-Lopez, Alberto, Thuan, Trinh
The Mg ii lambda lambda 2796, 2803 doublet has been suggested as a useful indirect indicator for the escape of Ly alpha and Lyman continuum (LyC) photons in local star-forming galaxies. However, studies to date have focused on small samples of galaxies with strong Mg ii or strong LyC emission. Here, we present the first study of Mg ii to probe a large dynamic range of galaxy properties, using newly obtained high-signal-to-noise, moderate-resolution spectra of Mg ii, for a sample of 34 galaxies selected from the Low-redshift Lyman Continuum Survey. We show that the galaxies in our sample have Mg ii profiles ranging from strong emission to P-Cygni profiles to pure absorption. We find that there is a significant trend (with a possibility of spurious correlations of similar to 2%) that galaxies that are detected as strong LyC emitters (LCEs) show larger equivalent widths of Mg ii emission, while non-LCEs tend to show evidence of more scattering and absorption features in Mg ii. We then find that Mg ii strongly correlates with Ly alpha in both equivalent width and escape fraction, regardless of whether emission or absorption dominates the Mg ii profiles. Furthermore, we show that, for galaxies that are categorized as Mg ii emitters, one can use the information of Mg ii, metallicity, and dust to estimate the escape fraction of LyC within a factor of similar to 3. These findings confirm that Mg ii lines can be used as a tool for selecting galaxies as LCEs and thus serve as an indirect indicator for the escape of Ly alpha and LyC.