A1 Refereed original research article in a scientific journal
NSF-DOE Vera C. Rubin Observatory Observations of Interstellar Comet 3I/ATLAS (C/2025 N1); 
Authors: Chandler, Colin Orion; Bernardinelli, Pedro H.; Juric, Mario; Singh, Devanshi; Hsieh, Henry H.; Sullivan, Ian; Jones, R. Lynne; Kurlander, Jacob A.; Vavilov, Dmitrii; Eggl, Siegfried; Holman, Matthew; Spoto, Federica; Schwamb, Megan E.; MacArthur, Lauren A.; Makadia, Rahil; Micheli, Marco; Heinze, Aren; Christensen, Eric J.; Beebe, Wilson; Roodman, Aaron; Lim, Kian-Tat; Jenness, Tim; Bosch, James; Smart, Brianna M.; Bellm, Eric; MacBride, Sean; Rawls, Meredith L.; Greenstreet, Sarah; Slater, Colin; Ivezic, Zeljko; Blum, Robert D.; Connolly, Andrew; Daues, Gregory; Gower, Michelle; Kalmbach, J. Bryce; Bannister, Michele T.; Dones, Luke; Dorsey, Rosemary C.; Farnocchia, Davide; Fraser, Wesley C.; Forbes, John C.; Fuentes, Cesar; Holt, Carrie E.; Inno, Laura; Jones, Geraint H.; Knight, Matthew M.; Lintott, Chris J.; Lister, Tim; Lupton, Robert; Magbanua, Mark Jesus M.; Malhotra, Renu; Mueller, Beatrice E. A.; Murtagh, Joseph; Pandey, Nitya; Reach, William T.; Samarasinha, Nalin H.; Seligman, Darryl Z.; Snodgrass, Colin; Solontoi, Michael; Szabo, Gyula M.; Veres, Peter; White, Ellie; Womack, Maria; Young, Leslie A.; Allbery, Russ; Anand, Shreya; Armellin, Roberto; Aubourg, Eric; Avdellidou, Chrysa; Azfar, Farrukh; Bauer, James; Bechtol, Keith; Becker, Valerie; Belyakov, Matthew; Benecchi, Susan D.; Bertini, Ivano; Bodewits, Dennis; Boeshaar, Patricia; Bolin, Bryce T.; Bose, Maitrayee; Boucaud, Alexandre; Boufleur, Rodrigo C.; Boutigny, Dominique; Bradshaw, Andrew; Braga-Ribas, Felipe; Bregeon, Johan; Buchanan, Laura E.; Calabrese, Daniel; Camargo, J. I. B.; Caplar, Neven; Carlin, Jeffrey L.; Carry, Benoit; Carvajal, Juan Pablo; Ceballo, Ross; Chiang, Hsin-Fang; Choi, Yumi; Combet, Celine; da Costa, Luiz; Cowan, Preeti; Crenshaw, John Franklin; Croft, Steve; Cuk, Matija; Daly, Philip N.; D'Ammando, Filippo; Daruich, Felipe; Daubard, Guillaume; Davenport, James R. A.; Daylan, Tansu; Delgado, Jennifer; Devillepoix, Hadrien A. R.; Doherty, Peter E.; Donaldson, Abbie; Drass, Holger; Deppe, Stephanie J. H.; Dubois-Felsmann, Gregory P.; Ferguson, Peter S.; Economou, Frossie; Eduardo, Marielle R.; Elorriaga, Ioana Sotuela; Englert, Anthony; Karavakis, Edward; Fanning, Kevin; Frissell, Maxwell K.; Fedorets, Grigori; Fernandes, Maryann Benny; Ferte, Agnes; Fisher-Levine, Merlin; Freytag, Mark L.; Fulle, Marco; Gandhi, Poshak; Gates, John; Gerdes, David W.; Gibbs, Alex R.; Gillan, A. Fraser; Orsini, Massimiliano Giordano; Glanzman, T.; Goodenow, Iain; Gomes-Junior, Altair Ramos; Gorsuch, Miranda R.; Granvik, Mikael; Guanaa, Wen; Guy, Leanne P.; Hammergren, Mark; Hanushevsky, Andrew; Hernandez, Fabio; Herrold, Adis; Hestroffer, Daniel; Hoblitt, Joshua; Homar, Guillem Megias; Hopkins, Matthew J.; Ieva, Simone; Ingraham, Patrick; Irving, David H.; Jannuzi, Buell T.; Jee, M. James; Jimenez, David; Juramy, Claire; Kahn, Steven M.; Kang, Yijung; Kannawadi, Arun; Kavelaars, Jj; Kelley, Michael S. P.; Kelkar, Kshitija; Kelvin, Lee S.; Kotov, Ivan; Koumjian, Alec; Kovacs, Gabor; Krughoff, K. Simon; Kryszczynsk, Agnieszka; Kubanek, Petr; Lage, Craig; Lange, Travis J.; Leget, Pierre-Francois; Le Guillou, Laurent; Levine, Benjamin; Levine, W. Garrett; Li, Zhuofu (Chester); Liang, Shuang; Licandro, Javier; Lin, Hsing Wen; Lisse, Carey; Lust, Nate B.; Lyttle, Ryan R.; Mahabal, Ashish A.; Mahlke, Max; Mainetti, Gabriele; Mandelbaum, Rachel; Margheim, Steven J.; Margoti, Giuliano; Marshall, Phil; Malagon, Andres A. Plazas; Marcet, Dusan; Melita, Mario D.; Menanteau, Felipe; Meyers, Joshua; Mills, Dave; Moniez, Marc; Marin, C. A. L. Morales; Morato, Naomi; More, Surhud; Morrison, Christopher B.; Mortensen, Kris; Moulane, Youssef; Mrakovcic, Karlo; Mueller, Fritz; Munoz-Gutierrez, Marco A.; Neal, Homer; Newcomer, F. M.; Nourbakhsh, Erfan; O'Connor, Paul; Oldag, Drew; Oldroyd, William J.; O'Mullane, William; Opitom, Cyrielle; Oszkiewicz, Dagmara; Page, Gary L.; Patterson, Jack; Patterson, Maria T.; Payne, Matthew J.; Pedersen, Eske M.; Peloton, Julien; Pereira, Chrystian Luciano; Peterson, John R.; Pietrowicz, Stephen R.; Podlewska-Gaca, Edyta; Polen, Rebekah; Polin, Daniel; Pollek, Hannah Mary Margaret; Qiu, Yongqiang; Quint, Bruno; Rabus, Markus; Ragozzine, Darin; Rajagopal, Jayadev; Ranabhat, Arianna; Reil, Kevin; Ribeiro, Tiago; Rice, Malena; Ridgway, Stephen T.; Ritz, Steven M.; Rivkin, Andrew S.; Robinson, James E.; Rozek, Agata; Rykoff, Eli; Manzano, Luis E. Salazar; Salnikov, Andrei; Sanchez, Bruno O.; Sanmartim, David; Sarid, Gal; Schambeau, Charles A.; Schindler, Rafe H.; Schmidt, Samuel J.; Schumacher, German; Schutt, Theo; Scolnic, Daniel; Seaman, Robert; Sebag, Jacques; Sedaghat, Nima; Seron, Jacqueline; Shaw, Richard A.; Shugart, Alysha; Sick, Jonathan; Singhal, Jaladh; Siraj, Amir; Sitarz, Michael C.; Snyder, Adam; Sobhani, Shahram; Soldahl, Christine; Spencer, Dallin; Stalder, Brian; Stetzler, Steven; Strauss, Alan; Stubbs, Christopher W.; Suberlak, Krzysztof L.; Swinbank, John D.; Szigeti, Laszlo; Taranu, Dan S.; Tauraso, Michael; Thayer, John Gregg; Thomas, Sandrine; Thornton, Adam; Tonietti, Luca; San Cipriano, Laura Toribio; Trilling, David E.; Trujillo, Chadwick A.; Tsai, Te-Wei; Tucker, Douglas L.; Turri, Max; Tyson, Tony; Urbach, Elana K.; van Reeven, Wouter; Villarreal, Antonia Sierra; Voutsinas, Stelios; Walter, Christopher W.; Wang, Yuankun (David); Ward, Charlotte; Warner, Michael; West, Maxine; Whittaker, Emerson; Wong, Ian; Wood-Vasey, W. M.; Yang, Bin; Ye, Quanzhi; Yoachim, Peter; Sanchez, R. Zanmar; Zhang, Jinshuo; Zhou, Conghao
Publisher: Institute of Physics Publishing
Publication year: 2026
Journal: Astrophysical Journal Letters
Article number: L35
Volume: 1001
Issue: 2
ISSN: 2041-8205
eISSN: 2041-8213
DOI: https://doi.org/10.3847/2041-8213/ae4b3a
Publication's open availability at the time of reporting: Open Access
Publication channel's open availability : Open Access publication channel
Web address : https://iopscience.iop.org/article/10.3847/2041-8213/ae4b3a
Self-archived copy’s web address: https://research.utu.fi/converis/portal/detail/Publication/526555805
Self-archived copy's licence: CC BY
Self-archived copy's version: Publisher`s PDF
We report on the observation and measurement of astrometry, photometry, morphology, and activity of the interstellar object 3I/ATLAS, also designated C/2025 N1 (ATLAS) with the NSF-DOE Vera C. Rubin Observatory. Comet 3I/ATLAS, the third known interstellar object, was discovered on UT 2025 July 1. Rubin Observatory had coincidentally collected images of the object’s region of the sky during routine commissioning. Facilitated by Rubin’s high resolution and large aperture, we successfully recovered object detections from Rubin observations spanning UT 2025 June 21 (10 days before discovery, when 3I/ATLAS was 4.5 au from the Sun) through the date of discovery, and we acquired additional images through UT 2025 July 20 as part of commissioning. We measure on-sky locations of 3I/ATLAS in Rubin ugrizy bands, with a typical precision of ∼70 mas, and briefly describe the reason this is coarser than our measured static source astrometric precision of ∼3 mas in Rubin images. We measure grizy magnitudes of 3I/ATLAS photometry at ∼0.01 mag precision, detecting no short-term photometric variability above 0.01 mag. We derive an estimated near-nucleus dust-to-nucleus scattering cross-sectional ratio of η ≳ 13 on UT 2025 July 2 based on Rubin photometry and an upper limit nucleus size computed from Hubble Space Telescope observations. We find Rubin colors of g − r = (0.657 ± 0.013) mag, r − i = (0.235 ± 0.018) mag, i − z = (0.147 ± 0.042) mag, and z − y = (0.047 ± 0.052) mag. These data represent the earliest observations of this object by a large (≳8 m class) telescope and illustrate the type of measurements (and discoveries) Rubin’s Legacy Survey of Space and Time will provide after it begins in early 2026.
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https://iopscience.iop.org/article/10.3847/2041-8213/ae4b3a#Acknowledgments
