{"file_date_updated":"2025-09-08T07:40:53Z","_id":"20294","article_type":"original","arxiv":1,"date_published":"2025-08-01T00:00:00Z","department":[{"_id":"JoMa"}],"status":"public","ddc":["520"],"year":"2025","intvolume":"       700","acknowledgement":"We are very grateful to the anonymous referee for instructive comments, which helped improve the overall quality and strengthen the analysis of this work. We thank Andrea Weibel for assistance with the HST and JWST photometric measurements used in this paper. This work is based on observations carried out under project number S23CY with the IRAM NOEMA Interferometer. IRAM is supported by INSU/CNRS (France), MPG (Germany) and IGN (Spain). This work is based in part on observations made with the NASA/ESA/CSA James Webb Space Telescope. The data were obtained from the Mikulski Archive for Space Telescopes at the Space Telescope Science Institute, which is operated by the Association of Universities for Research in Astronomy, Inc., under NASA contract NAS 5-03127 for JWST. These observations are associated with programs #1895 and #4762. Support for programs #1895 and #4762 was provided by NASA through a grant from the Space Telescope Science Institute, which is operated by the Association of Universities for Research in Astronomy, Inc., under NASA contract NAS 5-03127. This work has received funding from the Swiss State Secretariat for Education, Research and Innovation (SERI) under contract number MB22.00072, as well as from the Swiss National Science Foundation (SNSF) through project grant 200020_207349. The Cosmic Dawn Center (DAWN) is funded by the Danish National Research Foundation under grant DNRF140. This work is partially supported from the National Natural Science Foundation of China (12073003, 11721303, 11991052), and the China Manned Space Project (CMS-CSST-2021-A04 and CMS-CSST-2021-A06). Y.F. is supported by JSPS KAKENHI Grant Numbers JP22K21349 and JP23K13149. M.V. gratefully acknowledges financial support from the Independent Research Fund Denmark via grant numbers DFF 8021-00130 and 3103-00146 and from the Carlsberg Foundation via grant CF23-0417. VK acknowledges support from the University of Texas at Austin Cosmic Frontier Center. S.F. acknowledges support from NASA through the NASA Hubble Fellowship grant HST-HF2-51505.001-A awarded by the Space Telescope Science Institute, which is operated by the Association of Universities for Research in Astronomy, Incorporated, under NASA contract NAS5-26555. Support for this work for RPN was provided by NASA through the NASA Hubble Fellowship grant HST-HF2-51515.001-A awarded by the Space Telescope Science Institute, which is operated by the Association of Universities for Research in Astronomy, Incorporated, under NASA contract NAS5-26555.","citation":{"mla":"Xiao, Mengyuan, et al. “No [C II] or Dust Detection in Two Little Red Dots at Zspec &#62; 7.” <i>Astronomy and Astrophysics</i>, vol. 700, A231, EDP Sciences, 2025, doi:<a href=\"https://doi.org/10.1051/0004-6361/202554361\">10.1051/0004-6361/202554361</a>.","ieee":"M. Xiao <i>et al.</i>, “No [C II] or dust detection in two Little Red Dots at zspec &#62; 7,” <i>Astronomy and Astrophysics</i>, vol. 700. EDP Sciences, 2025.","chicago":"Xiao, Mengyuan, Pascal A. Oesch, Longji Bing, David Elbaz, Jorryt J Matthee, Yoshinobu Fudamoto, Seiji Fujimoto, et al. “No [C II] or Dust Detection in Two Little Red Dots at Zspec &#62; 7.” <i>Astronomy and Astrophysics</i>. EDP Sciences, 2025. <a href=\"https://doi.org/10.1051/0004-6361/202554361\">https://doi.org/10.1051/0004-6361/202554361</a>.","short":"M. Xiao, P.A. Oesch, L. Bing, D. Elbaz, J.J. Matthee, Y. Fudamoto, S. Fujimoto, R. Marques-Chaves, C.C. Williams, M. Dessauges-Zavadsky, F. Valentino, G. Brammer, A. Covelo-Paz, E. Daddi, J.P.U. Fynbo, S. Gillman, M. Ginolfi, E. Giovinazzo, J.E. Greene, Q. Gu, G. Illingworth, K. Inayoshi, V. Kokorev, R.A. Meyer, R.P. Naidu, N.A. Reddy, D. Schaerer, A. Shapley, M. Stefanon, C.L. Steinhardt, D.J. Setton, M. Vestergaard, T. Wang, Astronomy and Astrophysics 700 (2025).","apa":"Xiao, M., Oesch, P. A., Bing, L., Elbaz, D., Matthee, J. J., Fudamoto, Y., … Wang, T. (2025). No [C II] or dust detection in two Little Red Dots at zspec &#62; 7. <i>Astronomy and Astrophysics</i>. EDP Sciences. <a href=\"https://doi.org/10.1051/0004-6361/202554361\">https://doi.org/10.1051/0004-6361/202554361</a>","ista":"Xiao M, Oesch PA, Bing L, Elbaz D, Matthee JJ, Fudamoto Y, Fujimoto S, Marques-Chaves R, Williams CC, Dessauges-Zavadsky M, Valentino F, Brammer G, Covelo-Paz A, Daddi E, Fynbo JPU, Gillman S, Ginolfi M, Giovinazzo E, Greene JE, Gu Q, Illingworth G, Inayoshi K, Kokorev V, Meyer RA, Naidu RP, Reddy NA, Schaerer D, Shapley A, Stefanon M, Steinhardt CL, Setton DJ, Vestergaard M, Wang T. 2025. No [C II] or dust detection in two Little Red Dots at zspec &#62; 7. Astronomy and Astrophysics. 700, A231.","ama":"Xiao M, Oesch PA, Bing L, et al. No [C II] or dust detection in two Little Red Dots at zspec &#62; 7. <i>Astronomy and Astrophysics</i>. 2025;700. doi:<a href=\"https://doi.org/10.1051/0004-6361/202554361\">10.1051/0004-6361/202554361</a>"},"publication_identifier":{"issn":["0004-6361"],"eissn":["1432-0746"]},"publication_status":"published","day":"01","volume":700,"isi":1,"publication":"Astronomy and Astrophysics","oa":1,"month":"08","tmp":{"short":"CC BY (4.0)","image":"/images/cc_by.png","legal_code_url":"https://creativecommons.org/licenses/by/4.0/legalcode","name":"Creative Commons Attribution 4.0 International Public License (CC-BY 4.0)"},"quality_controlled":"1","doi":"10.1051/0004-6361/202554361","title":"No [C II] or dust detection in two Little Red Dots at zspec > 7","scopus_import":"1","OA_place":"publisher","date_updated":"2025-09-30T14:32:00Z","article_processing_charge":"No","article_number":"A231","file":[{"checksum":"fab2168609078b8336be01ef13b3238e","content_type":"application/pdf","relation":"main_file","date_updated":"2025-09-08T07:40:53Z","file_size":3648334,"success":1,"date_created":"2025-09-08T07:40:53Z","file_id":"20308","file_name":"2025_AstronomyAstrophysics_Xiao.pdf","access_level":"open_access","creator":"dernst"}],"type":"journal_article","oa_version":"Published Version","language":[{"iso":"eng"}],"external_id":{"isi":["001559174700004"],"arxiv":["2503.01945"]},"has_accepted_license":"1","PlanS_conform":"1","user_id":"317138e5-6ab7-11ef-aa6d-ffef3953e345","publisher":"EDP Sciences","author":[{"full_name":"Xiao, Mengyuan","last_name":"Xiao","first_name":"Mengyuan"},{"last_name":"Oesch","full_name":"Oesch, Pascal A.","first_name":"Pascal A."},{"full_name":"Bing, Longji","last_name":"Bing","first_name":"Longji"},{"last_name":"Elbaz","full_name":"Elbaz, David","first_name":"David"},{"id":"7439a258-f3c0-11ec-9501-9df22fe06720","first_name":"Jorryt J","last_name":"Matthee","orcid":"0000-0003-2871-127X","full_name":"Matthee, Jorryt J"},{"first_name":"Yoshinobu","full_name":"Fudamoto, Yoshinobu","last_name":"Fudamoto"},{"last_name":"Fujimoto","full_name":"Fujimoto, Seiji","first_name":"Seiji"},{"last_name":"Marques-Chaves","full_name":"Marques-Chaves, Rui","first_name":"Rui"},{"first_name":"Christina C.","last_name":"Williams","full_name":"Williams, Christina C."},{"last_name":"Dessauges-Zavadsky","full_name":"Dessauges-Zavadsky, Miroslava","first_name":"Miroslava"},{"first_name":"Francesco","full_name":"Valentino, Francesco","last_name":"Valentino"},{"first_name":"Gabriel","full_name":"Brammer, Gabriel","last_name":"Brammer"},{"full_name":"Covelo-Paz, Alba","last_name":"Covelo-Paz","first_name":"Alba"},{"first_name":"Emanuele","last_name":"Daddi","full_name":"Daddi, Emanuele"},{"last_name":"Fynbo","full_name":"Fynbo, Johan P.U.","first_name":"Johan P.U."},{"first_name":"Steven","last_name":"Gillman","full_name":"Gillman, Steven"},{"first_name":"Michele","last_name":"Ginolfi","full_name":"Ginolfi, Michele"},{"first_name":"Emma","full_name":"Giovinazzo, Emma","last_name":"Giovinazzo"},{"last_name":"Greene","full_name":"Greene, Jenny E.","first_name":"Jenny E."},{"full_name":"Gu, Qiusheng","last_name":"Gu","first_name":"Qiusheng"},{"full_name":"Illingworth, Garth","last_name":"Illingworth","first_name":"Garth"},{"full_name":"Inayoshi, Kohei","last_name":"Inayoshi","first_name":"Kohei"},{"first_name":"Vasily","full_name":"Kokorev, Vasily","last_name":"Kokorev"},{"last_name":"Meyer","full_name":"Meyer, Romain A.","first_name":"Romain A."},{"last_name":"Naidu","full_name":"Naidu, Rohan P.","first_name":"Rohan P."},{"last_name":"Reddy","full_name":"Reddy, Naveen A.","first_name":"Naveen A."},{"full_name":"Schaerer, Daniel","last_name":"Schaerer","first_name":"Daniel"},{"last_name":"Shapley","full_name":"Shapley, Alice","first_name":"Alice"},{"full_name":"Stefanon, Mauro","last_name":"Stefanon","first_name":"Mauro"},{"first_name":"Charles L.","full_name":"Steinhardt, Charles L.","last_name":"Steinhardt"},{"first_name":"David J.","last_name":"Setton","full_name":"Setton, David J."},{"last_name":"Vestergaard","full_name":"Vestergaard, Marianne","first_name":"Marianne"},{"full_name":"Wang, Tao","last_name":"Wang","first_name":"Tao"}],"date_created":"2025-09-07T22:01:33Z","OA_type":"diamond","abstract":[{"lang":"eng","text":"Little Red Dots (LRDs) are compact, point-like sources characterized by their red color and broad Balmer lines; it is a matter of debate whether they are dominated by active galactic nuclei (AGNs) or dusty star-forming galaxies (DSFGs). Here we report two LRDs (ID9094 and ID2756) at zspec > 7 recently discovered in the JWST FRESCO GOODS-North field. Both satisfy the “v-shaped” color and compactness criteria for LRDs and are identified as Type-I AGN candidates based on their broad Hβ emission lines (full width at half maximum: 2280 ± 490 km s−1 for ID9094 and 1070 ± 240 km s−1 for ID2756) and narrow [O III] lines (≃300 − 400 km s−1). To investigate their nature, we conducted deep NOEMA follow-up observations targeting the [C II] 158 μm emission line and the 1.3 mm dust continuum. We do not detect [C II] or 1.3 mm continuum emission for either source. If the two LRDs were DSFGs, we would expect significant detections: > 16σ for [C II] and > 3σ for the 1.3 mm continuum of ID9094, and > 5σ for the [C II] of ID2756. Using the 3σ upper limits of [C II] and 1.3 mm, we performed two analyses: (1) UV-to-far-infrared spectral energy distribution fitting with and without AGN components, and (2) comparison of their properties with the L[C II]–SFRtot empirical relation. Both analyses are consistent with a scenario in which AGN activity contributes to the observed properties, though a dusty star-forming origin cannot be fully ruled out. Our results highlight the importance of far-infrared observations for studying LRDs, a regime that remains largely unexplored."}]}