Institute of Space Sciences

The Euclid mission is expected to image millions of galaxies at high resolution, providing an extensive dataset with which to study galaxy evolution. Because galaxy morphology is both a fundamental parameter and one that is hard to determine for large samples, we investigate the application of deep learning in predicting the detailed morphologies of galaxies in Euclid using Zoobot, a convolutional neural network pretrained with 450 000 galaxies from the Galaxy Zoo project. We adapted Zoobot for use with emulated Euclid images generated based on Hubble Space Telescope COSMOS images and with labels provided by volunteers in the Galaxy Zoo: Hubble project. We experimented with different numbers of galaxies and various magnitude cuts during the training process. We demonstrate that the trained Zoobot model successfully measures detailed galaxy morphology in emulated Euclid images. It effectively predicts whether a galaxy has features and identifies and characterises various features, such as spiral arms, clumps, bars, discs, and central bulges. When compared to volunteer classifications, Zoobot achieves mean vote fraction deviations of less than 12% and an accuracy of above 91% for the confident volunteer classifications across most morphology types. However, the performance varies depending on the specific morphological class. For the global classes, such as disc or smooth galaxies, the mean deviations are less than 10%, with only 1000 training galaxies necessary to reach this performance. On the other hand, for more detailed structures and complex tasks, such as detecting and counting spiral arms or clumps, the deviations are slightly higher, of namely around 12% with 60 000 galaxies used for training. In order to enhance the performance on complex morphologies, we anticipate that a larger pool of labelled galaxies is needed, which could be obtained using crowd sourcing. We estimate that, with our model, the detailed morphology of approximately 800 million galaxies of the Euclid Wide Survey could be reliably measured and that approximately 230 million of these galaxies would display features. Finally, our findings imply that the model can be effectively adapted to new morphological labels. We demonstrate this adaptability by applying Zoobot to peculiar galaxies. In summary, our trained Zoobot CNN can readily predict morphological catalogues for Euclid images.

B. Aussel; S. Kruk; M. Walmsley; M. Huertas-Company; M. Castellano; C. J. Conselice; M. Delli Veneri; H. Domínguez Sánchez; P.-A. Duc; J. H. Knapen; U. Kuchner; A. La Marca; B. Margalef-Bentabol; F. R. Marleau; G. Stevens; Y. Toba; C. Tortora; L. Wang; N. Aghanim; B. Altieri; A. Amara; S. Andreon; N. Auricchio; M. Baldi; S. Bardelli; R. Bender; C. Bodendorf; D. Bonino; E. Branchini; M. Brescia; J. Brinchmann; S. Camera; V. Capobianco; C. Carbone; J. Carretero; S. Casas; S. Cavuoti; A. Cimatti; G. Congedo; L. Conversi; Y. Copin; F. Courbin; H. M. Courtois; M. Cropper; A. Da Silva; H. Degaudenzi; A. M. Di Giorgio; J. Dinis; F. Dubath; X. Dupac; S. Dusini; M. Farina; S. Farrens; S. Ferriol; S. Fotopoulou; M. Frailis; E. Franceschi; P. Franzetti; M. Fumana; S. Galeotta; B. Garilli; B. Gillis; C. Giocoli; A. Grazian; F. Grupp; S. V. H. Haugan; W. Holmes; I. Hook; F. Hormuth; A. Hornstrup; P. Hudelot; K. Jahnke; E. Keihänen; S. Kermiche; A. Kiessling; M. Kilbinger; B. Kubik; M. Kümmel; M. Kunz; H. Kurki-Suonio; R. Laureijs; S. Ligori; P. B. Lilje; V. Lindholm; I. Lloro; E. Maiorano; O. Mansutti; O. Marggraf; K. Markovic; N. Martinet; F. Marulli; R. Massey; S. Maurogordato; E. Medinaceli; S. Mei; Y. Mellier; M. Meneghetti; E. Merlin; G. Meylan; M. Moresco; L. Moscardini; E. Munari; S.-M. Niemi; C. Padilla; S. Paltani; F. Pasian; K. Pedersen; W. J. Percival; V. Pettorino; S. Pires; G. Polenta; M. Poncet; L. A. Popa; L. Pozzetti; F. Raison; R. Rebolo; A. Renzi; J. Rhodes; G. Riccio; E. Romelli; M. Roncarelli; E. Rossetti; R. Saglia; D. Sapone; B. Sartoris; M. Schirmer; P. Schneider; A. Secroun; G. Seidel; S. Serrano; C. Sirignano; G. Sirri; L. Stanco; J.-L. Starck; P. Tallada-Crespí; A. N. Taylor; H. I. Teplitz; I. Tereno; R. Toledo-Moreo; F. Torradeflot; I. Tutusaus; E. A. Valentijn; L. Valenziano; T. Vassallo; A. Veropalumbo; Y. Wang; J. Weller; A. Zacchei; G. Zamorani; J. Zoubian; E. Zucca; A. Biviano; M. Bolzonella; A. Boucaud; E. Bozzo; C. Burigana; C. Colodro-Conde; D. Di Ferdinando; R. Farinelli; J. Graciá-Carpio; G. Mainetti; S. Marcin; N. Mauri; C. Neissner; A. A. Nucita; Z. Sakr; V. Scottez; M. Tenti; M. Viel; M. Wiesmann; Y. Akrami; V. Allevato; S. Anselmi; C. Baccigalupi; M. Ballardini; S. Borgani; A. S. Borlaff; H. Bretonnière; S. Bruton; R. Cabanac; A. Calabro; A. Cappi; C. S. Carvalho; G. Castignani; T. Castro; G. Cañas-Herrera; K. C. Chambers; J. Coupon; O. Cucciati; S. Davini; G. De Lucia; G. Desprez; S. Di Domizio; H. Dole; A. Díaz-Sánchez; J. A. Escartin Vigo; S. Escoffier; I. Ferrero; F. Finelli; L. Gabarra; K. Ganga; J. García-Bellido; E. Gaztanaga; K. George; F. Giacomini; G. Gozaliasl; A. Gregorio; D. Guinet; A. Hall; H. Hildebrandt; A. Jimenez Muñoz; J. J. E. Kajava; V. Kansal; D. Karagiannis; C. C. Kirkpatrick; L. Legrand; A. Loureiro; J. Macias-Perez; M. Magliocchetti; R. Maoli; M. Martinelli; C. J. A. P. Martins; S. Matthew; M. Maturi; L. Maurin; R. B. Metcalf; M. Migliaccio; P. Monaco; G. Morgante; S. Nadathur; Nicholas A. Walton; A. Peel; A. Pezzotta; V. Popa; C. Porciani; D. Potter; M. Pöntinen; P. Reimberg; P.-F. Rocci; A. G. Sánchez; A. Schneider; E. Sefusatti; M. Sereno; P. Simon; A. Spurio Mancini; S. A. Stanford; J. Steinwagner; G. Testera; M. Tewes; R. Teyssier; S. Toft; S. Tosi; A. Troja; M. Tucci; C. Valieri; J. Valiviita; D. Vergani; I. A. Zinchenko. Euclid preparation. Astronomy & Astrophysics 2024, 689, A274 .

B. Aussel, S. Kruk, M. Walmsley, M. Huertas-Company, M. Castellano, C. J. Conselice, M. Delli Veneri, H. Domínguez Sánchez, P.-A. Duc, J. H. Knapen, U. Kuchner, A. La Marca, B. Margalef-Bentabol, F. R. Marleau, G. Stevens, Y. Toba, C. Tortora, L. Wang, N. Aghanim, B. Altieri, A. Amara, S. Andreon, N. Auricchio, M. Baldi, S. Bardelli, R. Bender, C. Bodendorf, D. Bonino, E. Branchini, M. Brescia, J. Brinchmann, S. Camera, V. Capobianco, C. Carbone, J. Carretero, S. Casas, S. Cavuoti, A. Cimatti, G. Congedo, L. Conversi, Y. Copin, F. Courbin, H. M. Courtois, M. Cropper, A. Da Silva, H. Degaudenzi, A. M. Di Giorgio, J. Dinis, F. Dubath, X. Dupac, S. Dusini, M. Farina, S. Farrens, S. Ferriol, S. Fotopoulou, M. Frailis, E. Franceschi, P. Franzetti, M. Fumana, S. Galeotta, B. Garilli, B. Gillis, C. Giocoli, A. Grazian, F. Grupp, S. V. H. Haugan, W. Holmes, I. Hook, F. Hormuth, A. Hornstrup, P. Hudelot, K. Jahnke, E. Keihänen, S. Kermiche, A. Kiessling, M. Kilbinger, B. Kubik, M. Kümmel, M. Kunz, H. Kurki-Suonio, R. Laureijs, S. Ligori, P. B. Lilje, V. Lindholm, I. Lloro, E. Maiorano, O. Mansutti, O. Marggraf, K. Markovic, N. Martinet, F. Marulli, R. Massey, S. Maurogordato, E. Medinaceli, S. Mei, Y. Mellier, M. Meneghetti, E. Merlin, G. Meylan, M. Moresco, L. Moscardini, E. Munari, S.-M. Niemi, C. Padilla, S. Paltani, F. Pasian, K. Pedersen, W. J. Percival, V. Pettorino, S. Pires, G. Polenta, M. Poncet, L. A. Popa, L. Pozzetti, F. Raison, R. Rebolo, A. Renzi, J. Rhodes, G. Riccio, E. Romelli, M. Roncarelli, E. Rossetti, R. Saglia, D. Sapone, B. Sartoris, M. Schirmer, P. Schneider, A. Secroun, G. Seidel, S. Serrano, C. Sirignano, G. Sirri, L. Stanco, J.-L. Starck, P. Tallada-Crespí, A. N. Taylor, H. I. Teplitz, I. Tereno, R. Toledo-Moreo, F. Torradeflot, I. Tutusaus, E. A. Valentijn, L. Valenziano, T. Vassallo, A. Veropalumbo, Y. Wang, J. Weller, A. Zacchei, G. Zamorani, J. Zoubian, E. Zucca, A. Biviano, M. Bolzonella, A. Boucaud, E. Bozzo, C. Burigana, C. Colodro-Conde, D. Di Ferdinando, R. Farinelli, J. Graciá-Carpio, G. Mainetti, S. Marcin, N. Mauri, C. Neissner, A. A. Nucita, Z. Sakr, V. Scottez, M. Tenti, M. Viel, M. Wiesmann, Y. Akrami, V. Allevato, S. Anselmi, C. Baccigalupi, M. Ballardini, S. Borgani, A. S. Borlaff, H. Bretonnière, S. Bruton, R. Cabanac, A. Calabro, A. Cappi, C. S. Carvalho, G. Castignani, T. Castro, G. Cañas-Herrera, K. C. Chambers, J. Coupon, O. Cucciati, S. Davini, G. De Lucia, G. Desprez, S. Di Domizio, H. Dole, A. Díaz-Sánchez, J. A. Escartin Vigo, S. Escoffier, I. Ferrero, F. Finelli, L. Gabarra, K. Ganga, J. García-Bellido, E. Gaztanaga, K. George, F. Giacomini, G. Gozaliasl, A. Gregorio, D. Guinet, A. Hall, H. Hildebrandt, A. Jimenez Muñoz, J. J. E. Kajava, V. Kansal, D. Karagiannis, C. C. Kirkpatrick, L. Legrand, A. Loureiro, J. Macias-Perez, M. Magliocchetti, R. Maoli, M. Martinelli, C. J. A. P. Martins, S. Matthew, M. Maturi, L. Maurin, R. B. Metcalf, M. Migliaccio, P. Monaco, G. Morgante, S. Nadathur, Nicholas A. Walton, A. Peel, A. Pezzotta, V. Popa, C. Porciani, D. Potter, M. Pöntinen, P. Reimberg, P.-F. Rocci, A. G. Sánchez, A. Schneider, E. Sefusatti, M. Sereno, P. Simon, A. Spurio Mancini, S. A. Stanford, J. Steinwagner, G. Testera, M. Tewes, R. Teyssier, S. Toft, S. Tosi, A. Troja, M. Tucci, C. Valieri, J. Valiviita, D. Vergani, I. A. Zinchenko. Euclid preparation. Astronomy & Astrophysics. 2024; 689 ():A274.

B. Aussel; S. Kruk; M. Walmsley; M. Huertas-Company; M. Castellano; C. J. Conselice; M. Delli Veneri; H. Domínguez Sánchez; P.-A. Duc; J. H. Knapen; U. Kuchner; A. La Marca; B. Margalef-Bentabol; F. R. Marleau; G. Stevens; Y. Toba; C. Tortora; L. Wang; N. Aghanim; B. Altieri; A. Amara; S. Andreon; N. Auricchio; M. Baldi; S. Bardelli; R. Bender; C. Bodendorf; D. Bonino; E. Branchini; M. Brescia; J. Brinchmann; S. Camera; V. Capobianco; C. Carbone; J. Carretero; S. Casas; S. Cavuoti; A. Cimatti; G. Congedo; L. Conversi; Y. Copin; F. Courbin; H. M. Courtois; M. Cropper; A. Da Silva; H. Degaudenzi; A. M. Di Giorgio; J. Dinis; F. Dubath; X. Dupac; S. Dusini; M. Farina; S. Farrens; S. Ferriol; S. Fotopoulou; M. Frailis; E. Franceschi; P. Franzetti; M. Fumana; S. Galeotta; B. Garilli; B. Gillis; C. Giocoli; A. Grazian; F. Grupp; S. V. H. Haugan; W. Holmes; I. Hook; F. Hormuth; A. Hornstrup; P. Hudelot; K. Jahnke; E. Keihänen; S. Kermiche; A. Kiessling; M. Kilbinger; B. Kubik; M. Kümmel; M. Kunz; H. Kurki-Suonio; R. Laureijs; S. Ligori; P. B. Lilje; V. Lindholm; I. Lloro; E. Maiorano; O. Mansutti; O. Marggraf; K. Markovic; N. Martinet; F. Marulli; R. Massey; S. Maurogordato; E. Medinaceli; S. Mei; Y. Mellier; M. Meneghetti; E. Merlin; G. Meylan; M. Moresco; L. Moscardini; E. Munari; S.-M. Niemi; C. Padilla; S. Paltani; F. Pasian; K. Pedersen; W. J. Percival; V. Pettorino; S. Pires; G. Polenta; M. Poncet; L. A. Popa; L. Pozzetti; F. Raison; R. Rebolo; A. Renzi; J. Rhodes; G. Riccio; E. Romelli; M. Roncarelli; E. Rossetti; R. Saglia; D. Sapone; B. Sartoris; M. Schirmer; P. Schneider; A. Secroun; G. Seidel; S. Serrano; C. Sirignano; G. Sirri; L. Stanco; J.-L. Starck; P. Tallada-Crespí; A. N. Taylor; H. I. Teplitz; I. Tereno; R. Toledo-Moreo; F. Torradeflot; I. Tutusaus; E. A. Valentijn; L. Valenziano; T. Vassallo; A. Veropalumbo; Y. Wang; J. Weller; A. Zacchei; G. Zamorani; J. Zoubian; E. Zucca; A. Biviano; M. Bolzonella; A. Boucaud; E. Bozzo; C. Burigana; C. Colodro-Conde; D. Di Ferdinando; R. Farinelli; J. Graciá-Carpio; G. Mainetti; S. Marcin; N. Mauri; C. Neissner; A. A. Nucita; Z. Sakr; V. Scottez; M. Tenti; M. Viel; M. Wiesmann; Y. Akrami; V. Allevato; S. Anselmi; C. Baccigalupi; M. Ballardini; S. Borgani; A. S. Borlaff; H. Bretonnière; S. Bruton; R. Cabanac; A. Calabro; A. Cappi; C. S. Carvalho; G. Castignani; T. Castro; G. Cañas-Herrera; K. C. Chambers; J. Coupon; O. Cucciati; S. Davini; G. De Lucia; G. Desprez; S. Di Domizio; H. Dole; A. Díaz-Sánchez; J. A. Escartin Vigo; S. Escoffier; I. Ferrero; F. Finelli; L. Gabarra; K. Ganga; J. García-Bellido; E. Gaztanaga; K. George; F. Giacomini; G. Gozaliasl; A. Gregorio; D. Guinet; A. Hall; H. Hildebrandt; A. Jimenez Muñoz; J. J. E. Kajava; V. Kansal; D. Karagiannis; C. C. Kirkpatrick; L. Legrand; A. Loureiro; J. Macias-Perez; M. Magliocchetti; R. Maoli; M. Martinelli; C. J. A. P. Martins; S. Matthew; M. Maturi; L. Maurin; R. B. Metcalf; M. Migliaccio; P. Monaco; G. Morgante; S. Nadathur; Nicholas A. Walton; A. Peel; A. Pezzotta; V. Popa; C. Porciani; D. Potter; M. Pöntinen; P. Reimberg; P.-F. Rocci; A. G. Sánchez; A. Schneider; E. Sefusatti; M. Sereno; P. Simon; A. Spurio Mancini; S. A. Stanford; J. Steinwagner; G. Testera; M. Tewes; R. Teyssier; S. Toft; S. Tosi; A. Troja; M. Tucci; C. Valieri; J. Valiviita; D. Vergani; I. A. Zinchenko. 2024. "Euclid preparation." Astronomy & Astrophysics 689, no. : A274.

Extracting precise cosmology from weak lensing surveys requires modelling the non-linear matter power spectrum, which is suppressed at small scales due to baryonic feedback processes. However, hydrodynamical galaxy formation simulations make widely varying predictions for the amplitude and extent of this effect. We use measurements of Dark Energy Survey Year 3 weak lensing (WL) and Atacama Cosmology Telescope DR5 kinematic Sunyaev–Zel’dovich (kSZ) to jointly constrain cosmological and astrophysical baryonic feedback parameters using a flexible analytical model, ‘baryonification’. First, using WL only, we compare the $S_8$ constraints using baryonification to a simulation-calibrated halo model, a simulation-based emulator model, and the approach of discarding WL measurements on small angular scales. We find that model flexibility can shift the value of $S_8$ and degrade the uncertainty. The kSZ provides additional constraints on the astrophysical parameters, with the joint WL + kSZ analysis constraining $S_8=0.823^{+0.019}_{-0.020}$. We measure the suppression of the non-linear matter power spectrum using WL + kSZ and constrain a mean feedback scenario that is more extreme than the predictions from most hydrodynamical simulations. We constrain the baryon fractions and the gas mass fractions and find them to be generally lower than inferred from X-ray observations and simulation predictions. We conclude that the WL + kSZ measurements provide a new and complementary benchmark for building a coherent picture of the impact of gas around galaxies across observations.

L Bigwood; A Amon; A Schneider; J Salcido; I G McCarthy; C Preston; D Sanchez; D Sijacki; E Schaan; S Ferraro; N Battaglia; A Chen; S Dodelson; A Roodman; A Pieres; A Ferté; A Alarcon; A Drlica-Wagner; A Choi; A Navarro-Alsina; A Campos; A J Ross; A Carnero Rosell; B Yin; B Yanny; C Sánchez; C Chang; C Davis; C Doux; D Gruen; E S Rykoff; E M Huff; E Sheldon; F Tarsitano; F Andrade-Oliveira; G M Bernstein; G Giannini; H T Diehl; H Huang; I Harrison; I Sevilla-Noarbe; I Tutusaus; J Elvin-Poole; J McCullough; J Zuntz; J Blazek; J DeRose; J Cordero; J Prat; J Myles; K Eckert; K Bechtol; K Herner; L F Secco; M Gatti; M Raveri; M Carrasco Kind; M R Becker; M A Troxel; M Jarvis; N MacCrann; O Friedrich; O Alves; P -F Leget; R Chen; R P Rollins; R H Wechsler; R A Gruendl; R Cawthon; S Allam; S L Bridle; S Pandey; S Everett; T Shin; W G Hartley; X Fang; Y Zhang; M Aguena; J Annis; D Bacon; E Bertin; S Bocquet; D Brooks; J Carretero; F J Castander; L N da Costa; M E S Pereira; J De Vicente; S Desai; P Doel; I Ferrero; B Flaugher; J Frieman; J García-Bellido; E Gaztanaga; G Gutierrez; S R Hinton; D L Hollowood; K Honscheid; D Huterer; D J James; K Kuehn; O Lahav; S Lee; J L Marshall; J Mena-Fernández; R Miquel; J Muir; M Paterno; A A Plazas Malagón; A Porredon; A K Romer; S Samuroff; E Sanchez; D Sanchez Cid; M Smith; M Soares-Santos; E Suchyta; M E C Swanson; G Tarle; C To; N Weaverdyck; J Weller; P Wiseman; M Yamamoto. Weak lensing combined with the kinetic Sunyaev–Zel’dovich effect: a study of baryonic feedback. Monthly Notices of the Royal Astronomical Society 2024, 534, 655 -682.

L Bigwood, A Amon, A Schneider, J Salcido, I G McCarthy, C Preston, D Sanchez, D Sijacki, E Schaan, S Ferraro, N Battaglia, A Chen, S Dodelson, A Roodman, A Pieres, A Ferté, A Alarcon, A Drlica-Wagner, A Choi, A Navarro-Alsina, A Campos, A J Ross, A Carnero Rosell, B Yin, B Yanny, C Sánchez, C Chang, C Davis, C Doux, D Gruen, E S Rykoff, E M Huff, E Sheldon, F Tarsitano, F Andrade-Oliveira, G M Bernstein, G Giannini, H T Diehl, H Huang, I Harrison, I Sevilla-Noarbe, I Tutusaus, J Elvin-Poole, J McCullough, J Zuntz, J Blazek, J DeRose, J Cordero, J Prat, J Myles, K Eckert, K Bechtol, K Herner, L F Secco, M Gatti, M Raveri, M Carrasco Kind, M R Becker, M A Troxel, M Jarvis, N MacCrann, O Friedrich, O Alves, P -F Leget, R Chen, R P Rollins, R H Wechsler, R A Gruendl, R Cawthon, S Allam, S L Bridle, S Pandey, S Everett, T Shin, W G Hartley, X Fang, Y Zhang, M Aguena, J Annis, D Bacon, E Bertin, S Bocquet, D Brooks, J Carretero, F J Castander, L N da Costa, M E S Pereira, J De Vicente, S Desai, P Doel, I Ferrero, B Flaugher, J Frieman, J García-Bellido, E Gaztanaga, G Gutierrez, S R Hinton, D L Hollowood, K Honscheid, D Huterer, D J James, K Kuehn, O Lahav, S Lee, J L Marshall, J Mena-Fernández, R Miquel, J Muir, M Paterno, A A Plazas Malagón, A Porredon, A K Romer, S Samuroff, E Sanchez, D Sanchez Cid, M Smith, M Soares-Santos, E Suchyta, M E C Swanson, G Tarle, C To, N Weaverdyck, J Weller, P Wiseman, M Yamamoto. Weak lensing combined with the kinetic Sunyaev–Zel’dovich effect: a study of baryonic feedback. Monthly Notices of the Royal Astronomical Society. 2024; 534 (1):655-682.

L Bigwood; A Amon; A Schneider; J Salcido; I G McCarthy; C Preston; D Sanchez; D Sijacki; E Schaan; S Ferraro; N Battaglia; A Chen; S Dodelson; A Roodman; A Pieres; A Ferté; A Alarcon; A Drlica-Wagner; A Choi; A Navarro-Alsina; A Campos; A J Ross; A Carnero Rosell; B Yin; B Yanny; C Sánchez; C Chang; C Davis; C Doux; D Gruen; E S Rykoff; E M Huff; E Sheldon; F Tarsitano; F Andrade-Oliveira; G M Bernstein; G Giannini; H T Diehl; H Huang; I Harrison; I Sevilla-Noarbe; I Tutusaus; J Elvin-Poole; J McCullough; J Zuntz; J Blazek; J DeRose; J Cordero; J Prat; J Myles; K Eckert; K Bechtol; K Herner; L F Secco; M Gatti; M Raveri; M Carrasco Kind; M R Becker; M A Troxel; M Jarvis; N MacCrann; O Friedrich; O Alves; P -F Leget; R Chen; R P Rollins; R H Wechsler; R A Gruendl; R Cawthon; S Allam; S L Bridle; S Pandey; S Everett; T Shin; W G Hartley; X Fang; Y Zhang; M Aguena; J Annis; D Bacon; E Bertin; S Bocquet; D Brooks; J Carretero; F J Castander; L N da Costa; M E S Pereira; J De Vicente; S Desai; P Doel; I Ferrero; B Flaugher; J Frieman; J García-Bellido; E Gaztanaga; G Gutierrez; S R Hinton; D L Hollowood; K Honscheid; D Huterer; D J James; K Kuehn; O Lahav; S Lee; J L Marshall; J Mena-Fernández; R Miquel; J Muir; M Paterno; A A Plazas Malagón; A Porredon; A K Romer; S Samuroff; E Sanchez; D Sanchez Cid; M Smith; M Soares-Santos; E Suchyta; M E C Swanson; G Tarle; C To; N Weaverdyck; J Weller; P Wiseman; M Yamamoto. 2024. "Weak lensing combined with the kinetic Sunyaev–Zel’dovich effect: a study of baryonic feedback." Monthly Notices of the Royal Astronomical Society 534, no. 1: 655-682.

We provide a short review of the recent developments in entropic cosmology based on two thermodynamic laws of the apparent horizon, namely the first and the second laws of thermodynamics. The first law essentially provides the change in entropy of the apparent horizon during the cosmic evolution of the universe; in particular, it is expressed by $TdS=-d\left(\rho V\right)+WdV$ (where W is the work density and other quantities have their usual meanings). In this way, the first law actually links various theories of gravity with the entropy of the apparent horizon. This leads to a natural question—“What is the form of the horizon entropy corresponding to a general modified theory of gravity?”. The second law of horizon thermodynamics states that the change in total entropy (the sum of horizon entropy + matter fields’ entropy) with respect to cosmic time must be positive, where the matter fields behave like an open system characterised by a non-zero chemical potential. The second law of horizon thermodynamics importantly provides model-independent constraints on entropic parameters. Finally, we discuss the standpoint of entropic cosmology on inflation (or bounce), reheating and primordial gravitational waves from the perspective of a generalised entropy function.

Shin’ichi Nojiri; Sergei D. Odintsov; Tanmoy Paul. Different Aspects of Entropic Cosmology. Universe 2024, 10, 352 .

Shin’ichi Nojiri, Sergei D. Odintsov, Tanmoy Paul. Different Aspects of Entropic Cosmology. Universe. 2024; 10 (9):352.

Shin’ichi Nojiri; Sergei D. Odintsov; Tanmoy Paul. 2024. "Different Aspects of Entropic Cosmology." Universe 10, no. 9: 352.