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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.
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 stellar halo in Local Group Hestia simulations
(EDP SCIENCES S A, 2023/09/11) Khoperskov, Sergey, Minchev, Ivan, Libeskind, Noam, Belokurov, Vasily, Steinmetz, Matthias, Gomez, Facundo A., Grand, Robert J. J., Hoffman, Yehuda, Knebe, Alexander, Sorce, Jenny G., Spaare, Martin, Tempel, Elmo, Vogelsberger, Mark
Stellar chemical abundances and kinematics provide key information for recovering the assembly history of galaxies. In this work we explore the chemo-chrono-kinematics of accreted and in situ stellar populations, by analyzing six M31 /Milky Way (MW) analogues from the HESTIA suite of cosmological hydrodynamics zoom-in simulations of the Local Group. We show that elemental abundances ([Fe =H], [Mg =Fe]) of merger debris in the stellar haloes are chemically distinct from the survived dwarf galaxies, in that they are [ alpha/Fe]-enhanced and have lower metallicity in the same stellar mass range. Therefore, mergers debris have abundances expected for stars originating from dwarfs that had their star formation activity quenched at early times. Accreted stellar haloes, including individual debris, reveal [Fe=H] and [Mg=Fe] gradients in the E - L-z plane, with the most metal-rich, [alpha/Fe]-poor stars, which have formed in the inner parts of the disrupted systems before the merger, contributing mainly to the central regions of the host galaxies. This results in negative metallicity gradients in the accreted components of stellar haloes at z = 0, seen also for the individual merger debris. We suggest, therefore, that abundance measurements of halo stars in the inner MW will allow constraining better the parameters, such as the mass and merger time, of MW ' s most massive merger Gaia-Sausage-Enceladus. The metallicity distribution functions (MDFs) of the individual debris show several peaks and the majority of debris have lower metallicity than the in situ stars in the prograde part of the E-L-z space. At the same time, non-rotating and retrograde accreted populations are very similar to the in situ stars in terms of [Fe=H] abundance. Prograde accreted stars show a prominent knee in the [Fe=H]-[Mg=Fe] plane, reaching up to solar [Mg=Fe], while retrograde stars typically contribute to the high-[Mg=Fe] sequence only. We find that the most metal-poor stars ([Fe=H]less than or similar to -1) of the HESTIA galaxies exhibit net rotation up to 80 km s (-1), which is consistent with the Aurora population recently identified in the MW. At higher metallicities ([Fe=H] approximate to -0.5 +/- 0.1) we detect a sharp transition (spin-up) from the turbulent phase to a regular disk-like rotation. Di fferent merger debris appear similar in the [Fe=H]-[Mg=Fe] plane, thus making it di fficult to identify individual events. However, combining a set of abundances, and especially stellar age, makes it possible to distinguish between di fferent debris.
The VANDELS survey: the ionizing properties of star-forming galaxies at 3=z=5 using deep rest-frame ultraviolet spectroscopy
(OXFORD UNIV PRESS, 2023/05/11) Saldana-Lopez, A., Schaerer, D., Chisholm, J., Calabro, A., Pentericci, L., Cullen, F., Saxena, A., Amorin, R., Carnall, A. C., Fontanot, F., Fynbo, J. P. U., Guaita, L., Hathi, N. P., Hibon, P., Ji, Z., McLeod, D. J., Pompei, E., Zamorani, G.
The physical properties of Epoch of Reionization (EoR) galaxies are still poorly constrained by observations. To better understand the ionizing properties of galaxies in the EoR, we investigate deep, rest-frame ultraviolet (UV) spectra of similar or equal to 500 star-forming galaxies at 3 = z & = 5 selected from the public ESO-VANDELS spectroscopic survey. The absolute ionizing photon escape fraction ($f_{rm esc}<^>{rm abs}$, i.e. the ratio of leaking against produced ionizing photons) is derived by combining absorption line measurements with estimates of the UV attenuation. The ionizing production efficiency (?(ion), i.e. the number of ionizing photons produced per non-ionizing UV luminosity) is calculated by fitting the far-UV (FUV) stellar continuum of the VANDELS galaxies. We find that the $f_{rm esc}<^>{rm abs}$ and ?(ion) parameters increase towards low-mass, blue UV-continuum slopes and strong Ly a emitting galaxies, and both are slightly higher-than-average for the UV-faintest galaxies in the sample. Potential Lyman Continuum Emitters (LCEs, $f_{rm esc}<^>{rm abs} ge 5{{ rm , per cent}}$) and selected Lyman Alpha Emitters (LAEs, W-Lya <= -20 angstrom) show systematically higher ?(ion) (log ?(ion)(Hz erg(-1)) approximate to 25.38, 25.41) than non-LCEs and non-LAEs (log ?(ion)(Hz erg(-1)) approximate to 25.18, 25.14) at similar UV magnitudes. This indicates very young underlying stellar populations (approximate to 10 Myr) at relatively low metallicities (approximate to 0.2 Z(circle dot)). The FUV non-ionizing spectra of potential LCEs is characterized by blue UV slopes (<=-2), enhanced Ly a emission (<=-25 angstrom), strong UV nebular lines (e.g. high ${rm C, small {IV}}$1550/${rm C, small {III}}$1908 >= 0.75 ratios), and weak absorption lines (<= 1 angstrom). The latter suggests the existence of low gas-column-density channels in the interstellar medium, which enables the escape of ionizing photons. By comparing our VANDELS results against other surveys in the literature, our findings imply that the ionizing budget in the EoR was likely dominated by UV-faint, low-mass, and dustless galaxies.
Using [Ne v]/[Ne iii] to Understand the Nature of Extreme-ionization Galaxies
(IOP Publishing Ltd, 2023/08/01) Cleri, Nikko J., Olivier, Grace M., Hutchison, Taylor A., Papovich, Casey, Trump, Jonathan R., Amorin, Ricardo O., Backhaus, Bren E., Berg, Danielle A., Fernandez, Vital, Finkelstein, Steven L., Fujimoto, Seiji, Hirschmann, Michaela, Kartaltepe, Jeyhan S., Kocevski, Dale D., Simons, Raymond C., Wilkins, Stephen M., Yung, L. Y. Aaron
Spectroscopic studies of extreme-ionization galaxies (EIGs) are critical to our understanding of exotic systems throughout cosmic time. These EIGs exhibit spectral features requiring >54.42 eV photons: the energy needed to ionize helium into He2+ fully and emit He ii recombination lines. Spectroscopic studies of EIGs can probe exotic stellar populations or accretion onto intermediate-mass black holes (& SIM,10(2)-10(5) M (& ODOT,)), which are the possibly key contributors to the reionization of the Universe. To facilitate the use of EIGs as probes of high-ionization systems, we focus on ratios constructed from several rest-frame UV/optical emission lines: [O iii] & lambda,5008, H & beta,, [Ne iii] & lambda,3870, [O ii] & lambda, & lambda,3727, 3729, and [Ne v] & lambda,3427. These lines probe the relative intensity at energies of 35.12, 13.62, 40.96, 13.62, and 97.12 eV, respectively, covering a wider range of ionization than traced by other common rest-frame UV/optical techniques. We use the ratios of these lines ([Ne v]/[Ne iii] & EQUIV, Ne53, [O iii]/H & beta,, and [Ne iii]/[O ii]), which are nearby in wavelength, mitigating the effects of dust attenuation and uncertainties in flux calibration. We make predictions from photoionization models constructed from Cloudy that use a broad range of stellar populations and black hole accretion models to explore the sensitivity of these line ratios to changes in the ionizing spectrum. We compare our models to observations from the Hubble Space Telescope and JWST of galaxies with strong high-ionization emission lines at z & SIM, 0, z & SIM, 2, and 5 < z < 8.5. We show that the Ne53 ratio can separate galaxies with ionization from normal stellar populations from those with active galactic nuclei and even exotic Population III models. We introduce new selection methods to identify galaxies with photoionization driven by Population III stars or intermediate-mass black hole accretion disks that could be identified in upcoming high-redshift spectroscopic surveys.
Origins of the Evil Eye: M64's Stellar Halo Reveals the Recent Accretion of an SMC-mass Satellite
(IOP Publishing Ltd, 2023/06/01) Smercina, Adam, Bell, Eric F. F., Price, Paul A. A., Bailin, Jeremy, Dalcanton, Julianne J. J., de Jong, Roelof S. S., D'Souza, Richard, Gozman, Katya, Jang, In Sung, Monachesi, Antonela, Nidever, David, Slater, Colin T. T.
M64, often called the Evil Eye galaxy, is unique among local galaxies. Beyond its dramatic, dusty nucleus, it also hosts an outer gas disk that counter-rotates relative to its stars. The mass of this outer disk is comparable to the gas content of the Small Magellanic Cloud (SMC), prompting the idea that it was likely accreted in a recent minor merger. Yet, detailed follow-up studies of M64's outer disk have shown no evidence of such an event, leading to other interpretations, such as a flyby interaction with the distant diffuse satellite Coma P. We present Subaru Hyper Suprime-Cam observations of M64's stellar halo, which resolve its stellar populations and reveal a spectacular radial shell feature, oriented similar to 30 degrees relative to the major axis and along the rotation axis of the outer gas disk. The shell is similar to 45 kpc southeast of M64, while a similar but more diffuse plume to the northwest extends to >100 kpc. We estimate a stellar mass and metallicity for the southern shell of M-star = 1.80 +/- 0.54 x 10(8) M-circle dot and [M/H] = -1.0, respectively, and a similar mass of 1.42 +/- 0.71 x 10(8) M-circle dot for the northern plume. Taking into account the accreted material in M64's inner disk, we estimate a total stellar mass for the progenitor satellite of M-star,M-prog similar or equal to 5 x 10(8) M-circle dot. These results suggest that M64 is in the final stages of a minor merger with a gas-rich satellite strikingly similar to the SMC, in which M64's accreted counter-rotating gas originated, and which is responsible for the formation of its dusty inner star-forming disk.
Structure, Kinematics, and Observability of the Large Magellanic Cloud's Dynamical Friction Wake in Cold versus Fuzzy Dark Matter
(IOP Publishing Ltd, 2023/09/01) Foote, Hayden R., Besla, Gurtina, Mocz, Philip, Garavito-Camargo, Nicolas, Lancaster, Lachlan, Sparre, Martin, Cunningham, Emily C., Vogelsberger, Mark, Gomez, Facundo A., Laporte, Chervin F. P.
The Large Magellanic Cloud (LMC) will induce a dynamical friction (DF) wake on infall to the Milky Way (MW). The MW's stellar halo will respond to the gravity of the LMC and the dark matter (DM) wake, forming a stellar counterpart to the DM wake. This provides a novel opportunity to constrain the properties of the DM particle. We present a suite of high-resolution, windtunnel-style simulations of the LMC's DF wake that compare the structure, kinematics, and stellar tracer response of the DM wake in cold DM (CDM), with and without self-gravity, versus fuzzy DM (FDM) with m a = 10-23 eV. We conclude that the self-gravity of the DM wake cannot be ignored. Its inclusion raises the wake's density by & SIM,10%, and holds the wake together over larger distances (& SIM,50 kpc) than if self-gravity is ignored. The DM wake's mass is comparable to the LMC's infall mass, meaning the DM wake is a significant perturber to the dynamics of MW halo tracers. An FDM wake is more granular in structure and is & SIM,20% dynamically colder than a CDM wake, but with comparable density. The granularity of an FDM wake increases the stars' kinematic response at the percent level compared to CDM, providing a possible avenue of distinguishing a CDM versus FDM wake. This underscores the need for kinematic measurements of stars in the stellar halo at distances of 70-100 kpc.
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.