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Unveiling the enigma of ATLAS17aeu

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posted on 15.08.2019, 16:14 by A Melandri, A Rossi, S Benetti, V D'Elia, S Piranomonte, E Palazzi, AJ Levan, M Branchesi, AJ Castro-Tirado, P D'Avanzo, Y-D Hu, G Raimondo, NR Tanvir, L Tomasella, L Amati, S Campana, R Carini, S Covino, F Cusano, M Dadina, M Della Valle, X Fan, P Garnavich, A Grado, G Greco, J Hjorth, JD Lyman, N Masetti, P O'Brien, E Pian, A Perego, R Salvaterra, L Stella, G Stratta, S Yang, A di Paola, MD Caballero-Garcia, AS Fruchter, A Giunta, F Longo, M Pinamonti, VV Sokolov, V Testa, AF Valeev, E Brocato, M Cantiello, F de Luise, LA Antonelli, L Pulone, S Ascenzi, G Israel, P Casella, A Stamerra, G Iannicola, M Lisi, F Getman, MT Botticella, P Schipani, L Nicastro, L Masetti, D Vergani, A Bulgarelli, G De Cesare, E Torresi, A Cimatti, M Brusa, G Lanzuisi, MOM Moresco, R Paladino, M Talia, E Maiorano, E Cappellaro, M Mapelli, R Ciolfi, M Turatto, G Tagliaferri, G Ghisellini, G Ghirlanda, MG Bernardini, A Possenti, M Burgay, S Marinoni, G Giuffrida, P Marrese, M Razzano, B Patricelli, G Cella, M Spera, S Savaglio, L Izzo, M Capaccioli, M Bulla
Aims. The unusual transient ATLAS17aeu was serendipitously detected within the sky localisation of the gravitational wave trigger GW 170104. The importance of a possible association with gravitational waves coming from a binary black hole merger led to an extensive follow-up campaign, with the aim of assessing a possible connection with GW 170104. Methods. With several telescopes, we carried out both photometric and spectroscopic observations of ATLAS17aeu, for several epochs, between ∼3 and ∼230 days after the first detection. Results. We studied in detail the temporal and spectroscopic properties of ATLAS17aeu and its host galaxy. Although at low significance and not conclusive, we found similarities to the spectral features of a broad-line supernova superposed onto an otherwise typical long-GRB afterglow. Based on analysis of the optical light curve, spectrum, and host galaxy spectral energy distribution, we conclude that the redshift of the source is probably z ' 0.5 ± 0.2. Conclusions. While the redshift range we have determined is marginally compatible with that of the gravitational wave event, the presence of a supernova component and the consistency of this transient with the Ep–Eiso correlation support the conclusion that ATLAS17aeu was associated with the long gamma-ray burst GRB 170105A. This rules out the association of the GRB 170105A/ATLAS17aeu transient with the gravitational wave event GW 170104, which was due to a binary black hole merger.


AM acknowledges the support from the ASI grant I/004/11/3. AR acknowledges support from Premiale LBT 2013. AJCT thanks the Spanish Ministry Project AYA2015-71718-R (including FEDER funds). LT and SB are partially supported by the PRIN-INAF 2016 with the project “Toward the SKA and CTA era: discovery, localisation, and physics of transient sources”. Partially based on observations collected at the Copernico 1.82 m telescope (Asiago, Italy) of the INAF - Osservatorio Astronomico di Padova. JH was supported by a VILLUM FONDEN Investigator grant (project number 16599). AFV is thankful to the Russian Science Foundation (grant 14-50-00043). This work made use of observations obtained with the Italian 3.6 m Telescopio Nazionale Galileo (TNG) and the 10.4 m Gran Telescopio Canarias (GTC), operated on the island of La Palma by the Fundación Galileo Galilei of the Instituto Nazionale di Astrofisica (INAF) at the Spanish Observatorio del Roque de los Muchachos of the Instituto de Astrofísica de Canarias, and also made use of observations obtained with the 8.4 m Large Binocular Telescope (LBT). The LBT is an international collaboration among institutions in Italy, the United States, and Germany. LBT Corporation partners are: Istituto Nazionale di Astrofisica, Italy; The University of Arizona on behalf of the Arizona university system; LBT Beteiligungsgesellschaft, Germany, representing the Max-Planck Society, the Astrophysical Institute Potsdam, and Heidelberg University; The Ohio State University; and The Research Corporation on behalf of The University of Notre Dame, University of Minnesota, and University of Virginia. We thank the TNG staff, in particular G. Andreuzzi, G. Mainella, A. Harutyunyan, and the LBT staff, in particular A. Gargiulo, for their valuable support with TNG and LBT observations and data reduction. We also acknowledge INAF financial support of the project “Gravitational Wave Astronomy with the first detections of adLIGO and adVIRGO experi



Astronomy and Astrophysics, 2019, 621, A81

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/Organisation/COLLEGE OF SCIENCE AND ENGINEERING/Department of Physics and Astronomy


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Based on observations made with the following telescopes: Copernico, TNG (under programme A34TAC_24), GTC (under programmes GTCMULTIPLE2D-16B and GTCMULTIPLE2G-17A), LBT (under programme 2016_2017_19), and HST (under programme GO14270). Spectral data for this source shown on this paper are available on the Weizmann Interactive Supernova Data Repository (WISeREP, https://wiserep.weizmann.ac.il/).