The Astrophysical Journal Letters (Jan 2024)
CEERS Key Paper. IX. Identifying Galaxy Mergers in CEERS NIRCam Images Using Random Forests and Convolutional Neural Networks
- Caitlin Rose,
- Jeyhan S. Kartaltepe,
- Gregory F. Snyder,
- Marc Huertas-Company,
- L. Y. Aaron Yung,
- Pablo Arrabal Haro,
- Micaela B. Bagley,
- Laura Bisigello,
- Antonello Calabrò,
- Nikko J. Cleri,
- Mark Dickinson,
- Henry C. Ferguson,
- Steven L. Finkelstein,
- Adriano Fontana,
- Andrea Grazian,
- Norman A. Grogin,
- Benne W. Holwerda,
- Kartheik G. Iyer,
- Lisa J. Kewley,
- Allison Kirkpatrick,
- Dale D. Kocevski,
- Anton M. Koekemoer,
- Jennifer M. Lotz,
- Ray A. Lucas,
- Lorenzo Napolitano,
- Casey Papovich,
- Laura Pentericci,
- Pablo G. Pérez-González,
- Nor Pirzkal,
- Swara Ravindranath,
- Rachel S. Somerville,
- Amber N. Straughn,
- Jonathan R. Trump,
- Stephen M. Wilkins,
- Guang Yang
Affiliations
- Caitlin Rose
- ORCiD
- Laboratory for Multiwavelength Astrophysics, School of Physics and Astronomy, Rochester Institute of Technology , 84 Lomb Memorial Drive, Rochester, NY 14623, USA
- Jeyhan S. Kartaltepe
- ORCiD
- Laboratory for Multiwavelength Astrophysics, School of Physics and Astronomy, Rochester Institute of Technology , 84 Lomb Memorial Drive, Rochester, NY 14623, USA
- Gregory F. Snyder
- ORCiD
- Space Telescope Science Institute , 3700 San Martin Drive, Baltimore, MD 21218, USA
- Marc Huertas-Company
- ORCiD
- Instituto de Astrofísica de Canarias , La Laguna, Tenerife, Spain; Universidad de la Laguna , La Laguna, Tenerife, Spain; Université Paris-Cité , LERMA—Observatoire de Paris, PSL, Paris, France
- L. Y. Aaron Yung
- ORCiD
- Space Telescope Science Institute , 3700 San Martin Drive, Baltimore, MD 21218, USA
- Pablo Arrabal Haro
- ORCiD
- NSF’s National Optical-Infrared Astronomy Research Laboratory , 950 North Cherry Avenue, Tucson, AZ 85719, USA
- Micaela B. Bagley
- ORCiD
- Department of Astronomy, The University of Texas at Austin , Austin, TX, USA
- Laura Bisigello
- ORCiD
- INAF, Istituto di Radioastronomia , Via Piero Gobetti 101, 40129 Bologna, Italy; Dipartimento di Fisica e Astronomia “G.Galilei,” Universitá di Padova , Via Marzolo 8, I-35131 Padova, Italy
- Antonello Calabrò
- ORCiD
- INAF—Osservatorio Astronomico di Roma , via di Frascati 33, 00078 Monte Porzio Catone, Italy
- Nikko J. Cleri
- ORCiD
- Department of Physics and Astronomy, Texas A&M University , College Station, TX 77843-4242, USA; George P. and Cynthia Woods Mitchell Institute for Fundamental Physics and Astronomy, Texas A&M University , College Station, TX 77843-4242, USA
- Mark Dickinson
- ORCiD
- NSF’s National Optical-Infrared Astronomy Research Laboratory , 950 North Cherry Avenue, Tucson, AZ 85719, USA
- Henry C. Ferguson
- ORCiD
- Space Telescope Science Institute , 3700 San Martin Drive, Baltimore, MD 21218, USA
- Steven L. Finkelstein
- ORCiD
- Department of Astronomy, The University of Texas at Austin , Austin, TX, USA
- Adriano Fontana
- ORCiD
- INAF—Osservatorio Astronomico di Roma , via di Frascati 33, 00078 Monte Porzio Catone, Italy
- Andrea Grazian
- ORCiD
- INAF—Osservatorio Astronomico di Padova , Vicolo dell’Osservatorio 5, I-35122, Padova, Italy
- Norman A. Grogin
- ORCiD
- Space Telescope Science Institute , 3700 San Martin Drive, Baltimore, MD 21218, USA
- Benne W. Holwerda
- ORCiD
- Physics & Astronomy Department, University of Louisville , Louisville, KY 40292, USA
- Kartheik G. Iyer
- ORCiD
- Dunlap Institute for Astronomy & Astrophysics, University of Toronto , Toronto, ON M5S 3H4, Canada
- Lisa J. Kewley
- ORCiD
- Center for Astrophysics—Harvard & Smithsonian , 60 Garden Street, Cambridge, MA 02138, USA
- Allison Kirkpatrick
- ORCiD
- Department of Physics and Astronomy, University of Kansas , Lawrence, KS 66045, USA
- Dale D. Kocevski
- ORCiD
- Department of Physics and Astronomy, Colby College , Waterville, ME 04901, USA
- Anton M. Koekemoer
- ORCiD
- Space Telescope Science Institute , 3700 San Martin Drive, Baltimore, MD 21218, USA
- Jennifer M. Lotz
- ORCiD
- Gemini Observatory/NSF’s National Optical-Infrared Astronomy Research Laboratory , 950 North Cherry Avenue, Tucson, AZ 85719, USA
- Ray A. Lucas
- ORCiD
- Space Telescope Science Institute , 3700 San Martin Drive, Baltimore, MD 21218, USA
- Lorenzo Napolitano
- ORCiD
- INAF—Osservatorio Astronomico di Roma , via di Frascati 33, 00078 Monte Porzio Catone, Italy; Dipartimento di Fisica, Università di Roma Sapienza , Città Universitaria di Roma—Sapienza, Piazzale Aldo Moro, 2, 00185, Roma, Italy
- Casey Papovich
- ORCiD
- Department of Physics and Astronomy, Texas A&M University , College Station, TX 77843-4242, USA; George P. and Cynthia Woods Mitchell Institute for Fundamental Physics and Astronomy, Texas A&M University , College Station, TX 77843-4242, USA
- Laura Pentericci
- ORCiD
- INAF—Osservatorio Astronomico di Roma , via di Frascati 33, 00078 Monte Porzio Catone, Italy
- Pablo G. Pérez-González
- ORCiD
- Centro de Astrobiología (CAB) , CSIC-INTA, Ctra. de Ajalvir km 4, Torrejón de Ardoz, E-28850, Madrid, Spain
- Nor Pirzkal
- ORCiD
- ESA/AURA Space Telescope Science Institute , USA
- Swara Ravindranath
- ORCiD
- Astrophysics Science Division, NASA Goddard Space Flight Center , 8800 Greenbelt Road, Greenbelt, MD 20771, USA; Center for Research and Exploration in Space Science and Technology II, Department of Physics, Catholic University of America , 620 Michigan Avenue NE, Washington, DC 20064, USA
- Rachel S. Somerville
- ORCiD
- Center for Computational Astrophysics, Flatiron Institute , 162 5th Avenue, New York, NY 10010, USA
- Amber N. Straughn
- ORCiD
- Astrophysics Science Division, NASA Goddard Space Flight Center , 8800 Greenbelt Road, Greenbelt, MD 20771, USA
- Jonathan R. Trump
- ORCiD
- Department of Physics, 196 Auditorium Road, Unit 3046, University of Connecticut , Storrs, CT 06269, USA
- Stephen M. Wilkins
- ORCiD
- Astronomy Centre, University of Sussex , Falmer, Brighton BN1 9QH, UK; Institute of Space Sciences and Astronomy, University of Malta , Msida MSD 2080, Malta
- Guang Yang
- ORCiD
- Nanjing Institute of Astronomical Optics and Technology , Nanjing 210042, People's Republic of China
- DOI
- https://doi.org/10.3847/2041-8213/ad8dd4
- Journal volume & issue
-
Vol. 976,
no. 1
p. L8
Abstract
A crucial yet challenging task in galaxy evolution studies is the identification of distant merging galaxies, a task that suffers from a variety of issues ranging from telescope sensitivities and limitations to the inherently chaotic morphologies of young galaxies. In this paper, we use random forests and convolutional neural networks to identify high-redshift JWST Cosmic Evolution Early Release Science Survey (CEERS) galaxy mergers. We train these algorithms on simulated 3 < z < 5 CEERS galaxies created from the IllustrisTNG subhalo morphologies and the Santa Cruz SAM light cone. We apply our models to observed CEERS galaxies at 3 < z < 5. We find that our models correctly classify ∼60%–70% of simulated merging and nonmerging galaxies; better performance on the merger class comes at the expense of misclassifying more nonmergers. We could achieve more accurate classifications, as well as test for a dependency on physical parameters such as gas fraction, mass ratio, and relative orbits, by curating larger training sets. When applied to real CEERS galaxies using visual classifications as ground truth, the random forests correctly classified 40%–60% of mergers and nonmergers at 3 < z < 4 but tended to classify most objects as nonmergers at 4 < z < 5 (misclassifying ∼70% of visually classified mergers). On the other hand, the CNNs tended to classify most objects as mergers across all redshifts (misclassifying 80%–90% of visually classified nonmergers). We investigate what features the models find most useful, as well as the characteristics of false positives and false negatives, and also calculate merger rates derived from the identifications made by the models.
Keywords
- James Webb Space Telescope
- Galaxy mergers
- Astronomical simulations
- Random Forests
- Convolutional neural networks
