A1 Refereed original research article in a scientific journal
CSS 161010: A Luminous Fast Blue Optical Transient with Broad Blueshifted Hydrogen Lines
Authors: Gutierrez, Claudia P.; Mattila, Seppo; Lundqvist, Peter; Dessart, Luc; Gonzalez-Gaitan, Santiago; Jonker, Peter G.; Dong, Subo; Coppejans, Deanne; Chen, Ping; Charalampopoulos, Panos; Elias-Rosa, Nancy; Reynolds, Thomas M.; Kochanek, Christopher; Fraser, Morgan; Pastorello, Andrea; Gromadzki, Mariusz; Neustadt, Jack; Benetti, Stefano; Kankare, Erkki; Kangas, Tuomas; Kotak, Rubina; Stritzinger, Maximilian D.; Wevers, Thomas; Zhang, Bing; Bersier, David; Bose, Subhash; Buckley, David A. H.; Dastidar, Raya; Gangopadhyay, Anjasha; Hamanowicz, Aleksandra; Kollmeier, Juna A.; Mao, Jirong; Misra, Kuntal; Potter, Stephen. B.; Prieto, Jose L.; Romero-Colmenero, Encarni; Singh, Mridweeka; Somero, Auni; Terreran, Giacomo; Vaisanen, Petri; Wyrzykowski, Lukasz
Publisher: Institute of Physics Publishing
Publishing place: BRISTOL
Publication year: 2024
Journal: Astrophysical Journal
Journal name in source: ASTROPHYSICAL JOURNAL
Journal acronym: ASTROPHYS J
Article number: 162
Volume: 977
Issue: 2
Number of pages: 21
ISSN: 0004-637X
eISSN: 1538-4357
DOI: https://doi.org/10.3847/1538-4357/ad89a5(external)
Self-archived copy’s web address: https://research.utu.fi/converis/portal/detail/Publication/477410786(external)
We present ultraviolet, optical, and near-infrared photometric and optical spectroscopic observations of the luminous fast blue optical transient (LFBOT) CSS 161010:045834-081803 (CSS 161010). The transient was found in a low-redshift (z = 0.033) dwarf galaxy. The light curves of CSS 161010 are characterized by an extremely fast evolution and blue colors. The V-band light curve shows that CSS 161010 reaches an absolute peak of MVmax= -20.66 +/- 0.06 mag in 3.8 days from the start of the outburst. After maximum, CSS 161010 follows a power-law decline ∝t -2.8 +/- 0.1 in all optical bands. These photometric properties are comparable to those of well-observed LFBOTs such as AT 2018cow, AT 2020mrf, and AT 2020xnd. However, unlike these objects, the spectra of CSS 161010 show a remarkable transformation from a blue and featureless continuum to spectra dominated by very broad, entirely blueshifted hydrogen emission lines with velocities of up to 10% of the speed of light. The persistent blueshifted emission and the lack of any emission at the rest wavelength of CSS 161010 are unique features not seen in any transient before CSS 161010. The combined observational properties of CSS 161010 and its M* ~ 108M⊙ dwarf galaxy host favor the tidal disruption of a star by an intermediate-mass black hole as its origin.
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Funding information in the publication:
C.P.G., S.M., and L.D. thank the Munich Institute for Astro-, Particle and BioPhysics (MIAPbP), which is funded by the Deutsche Forschungsgemeinschaft (DFG, German Research Foundation) under Germany's Excellence Strategy—EXC-2094—390783311, for the useful discussions.
C.P.G. acknowledges financial support from the Secretary of Universities and Research (Government of Catalonia) and by the Horizon 2020 Research and Innovation Programme of the European Union under the Marie Skłodowska-Curie and the Beatriu de Pinós 2021 BP 00168 program, from the Spanish Ministerio de Ciencia e Innovación (MCIN) and the Agencia Estatal de Investigación (AEI) 10.13039/501100011033 under the PID2020-115253GA-I00 HOSTFLOWS project, and the program Unidad de Excelencia María de Maeztu CEX2020-001058-M. S.M. and T.M.R. acknowledge financial support from the Research Council of Finland project 350458. P.L. acknowledges support from the Swedish Research Council. S.G.G. acknowledges support by FCT under Project No. UIDB/00099/2020. P.G.J. has received funding from the European Research Council (ERC) under the European Union's Horizon 2020 research and innovation program (grant agreement No. 101095973). S.D. acknowledges the National Natural Science Foundation of China (grant No. 12133005) and the New Cornerstone Science Foundation through the XPLORER PRIZE. D.C. acknowledges support from the Science and Technology Facilities Council (STFC) grant number ST/X001121/1. N.E.R. acknowledges partial support from MIUR, PRIN 2017 (grant 20179ZF5KS). N.E.R., A.P., and S.B. acknowledge the PRIN-INAF 2022 grant "Shedding light on the nature of gap transients: from the observations to the models." C.S.K. is supported by NSF grants AST-1908570, AST-2307385, and AST-2407206. M.F. is supported by a Royal Society—Science Foundation Ireland University Research Fellowship. P.C. and R.K. acknowledge support via the Research Council of Finland (grant 340613). M.D.S. is funded by the Independent Research Fund Denmark (IRFD, grant No. 10.46540/2032-00022B). J.L.P. acknowledges support from ANID, Millennium Science Initiative, AIM23-0001. L.W. and M.G. acknowledge funding from the European Union's Horizon 2020 research and innovation program under grant agreement No. 101004719 (OPTICON-RadioNET Pilot, ORP). L.W., M.G., and A.H. acknowledge support from the Polish National Science Centre (NCN) grant No. 2015/17/B/ST9/03167 (OPUS) to L.W., and the Polish participation in SALT is funded by grant No. MNiSW DIR/WK/2016/07. J.M. has the support of the National Key R&D Program of China (2023YFE0101200), the National Natural Science Foundation of China (NSFC 12393813), CSST grant CMS-CSST-2021-A06, and the Yunnan Revitalization Talent Support Program (YunLing Scholar Project). E.R.C. acknowledges support from the National Research Foundation of South Africa. R.D. acknowledges funds by ANID grant FONDECYT Post-doctorado No. 3220449. The Cosmic Dawn Center (DAWN) is funded by the Danish National Research Foundation under grant DNRF140.
