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Your search keyword '"Francesca Onori"' showing total 2 results
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2 results on '"Francesca Onori"'

1. Light-curve Structure and Hα Line Formation in the Tidal Disruption Event AT 2019azh

Author

Sara Faris, Iair Arcavi, Lydia Makrygianni, Daichi Hiramatsu, Giacomo Terreran, Joseph Farah, D. Andrew Howell, Curtis McCully, Megan Newsome, Estefania Padilla Gonzalez, Craig Pellegrino, K. Azalee Bostroem, Wiam Abojanb, Marco C. Lam, Lina Tomasella, Thomas G. Brink, Alexei V. Filippenko, K. Decker French, Peter Clark, Or Graur, Giorgos Leloudas, Mariusz Gromadzki, Joseph P. Anderson, Matt Nicholl, Claudia P. Gutiérrez, Erkki Kankare, Cosimo Inserra, Lluís Galbany, Thomas Reynolds, Seppo Mattila, Teppo Heikkilä, Yanan Wang, Francesca Onori, Thomas Wevers, Eric R. Coughlin, Panos Charalampopoulos, and Joel Johansson

Subjects
Accretion, Tidal disruption, Supermassive black holes, Ultraviolet transient sources, Astrophysics, QB460-466
Abstract

AT 2019azh is a H+He tidal disruption event (TDE) with one of the most extensive ultraviolet and optical data sets available to date. We present our photometric and spectroscopic observations of this event starting several weeks before and out to approximately 2 yr after the g -band's peak brightness and combine them with public photometric data. This extensive data set robustly reveals a change in the light-curve slope and a possible bump in the rising light curve of a TDE for the first time, which may indicate more than one dominant emission mechanism contributing to the pre-peak light curve. Indeed, we find that the MOSFiT -derived parameters of AT 2019azh, which assume reprocessed accretion as the sole source of emission, are not entirely self-consistent. We further confirm the relation seen in previous TDEs whereby the redder emission peaks later than the bluer emission. The post-peak bolometric light curve of AT 2019azh is better described by an exponential decline than by the canonical t ^−5/3 (and in fact any) power-law decline. We find a possible mid-infrared excess around the peak optical luminosity, but cannot determine its origin. In addition, we provide the earliest measurements of the H α emission-line evolution and find no significant time delay between the peak of the V -band light curve and that of the H α luminosity. These results can be used to constrain future models of TDE line formation and emission mechanisms in general. More pre-peak 1–2 days cadence observations of TDEs are required to determine whether the characteristics observed here are common among TDEs. More importantly, detailed emission models are needed to fully exploit such observations for understanding the emission physics of TDEs.

Published
2024
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2. A magnetar giant flare in the nearby starburst galaxy M82

Author

Mereghetti, S, Rigoselli, M, Salvaterra, R, Pacholski, D, Craig Rodi, J, Gotz, D, Arrigoni, E, D’Avanzo, P, Adami, C, Bazzano, A, Bozzo, E, Brivio, R, Campana, S, Cappellaro, E, Chenevez, J, De Luise, F, Ducci, L, Esposito, P, Ferrigno, C, Ferro, M, Luca Israel, G, Le Floc’h, E, Martin-Carrillo, A, Onori, F, Rea, N, Reguitti, A, Savchenko, V, Souami, D, Tartaglia, L, Thuillot, W, Tiengo, A, Tomasella, L, Topinka, M, Turpin, D, Ubertini, P, Sandro Mereghetti, Michela Rigoselli, Ruben Salvaterra, Dominik Patryk Pacholski, James Craig Rodi, Diego Gotz, Edoardo Arrigoni, Paolo D’Avanzo, Christophe Adami, Angela Bazzano, Enrico Bozzo, Riccardo Brivio, Sergio Campana, Enrico Cappellaro, Jerome Chenevez, Fiore De Luise, Lorenzo Ducci, Paolo Esposito, Carlo Ferrigno, Matteo Ferro, Gian Luca Israel, Emeric Le Floc’h, Antonio Martin-Carrillo, Francesca Onori, Nanda Rea, Andrea Reguitti, Volodymyr Savchenko, Damya Souami, Leonardo Tartaglia, William Thuillot, Andrea Tiengo, Lina Tomasella, Martin Topinka, Damien Turpin, Pietro Ubertini, Mereghetti, S, Rigoselli, M, Salvaterra, R, Pacholski, D, Craig Rodi, J, Gotz, D, Arrigoni, E, D’Avanzo, P, Adami, C, Bazzano, A, Bozzo, E, Brivio, R, Campana, S, Cappellaro, E, Chenevez, J, De Luise, F, Ducci, L, Esposito, P, Ferrigno, C, Ferro, M, Luca Israel, G, Le Floc’h, E, Martin-Carrillo, A, Onori, F, Rea, N, Reguitti, A, Savchenko, V, Souami, D, Tartaglia, L, Thuillot, W, Tiengo, A, Tomasella, L, Topinka, M, Turpin, D, Ubertini, P, Sandro Mereghetti, Michela Rigoselli, Ruben Salvaterra, Dominik Patryk Pacholski, James Craig Rodi, Diego Gotz, Edoardo Arrigoni, Paolo D’Avanzo, Christophe Adami, Angela Bazzano, Enrico Bozzo, Riccardo Brivio, Sergio Campana, Enrico Cappellaro, Jerome Chenevez, Fiore De Luise, Lorenzo Ducci, Paolo Esposito, Carlo Ferrigno, Matteo Ferro, Gian Luca Israel, Emeric Le Floc’h, Antonio Martin-Carrillo, Francesca Onori, Nanda Rea, Andrea Reguitti, Volodymyr Savchenko, Damya Souami, Leonardo Tartaglia, William Thuillot, Andrea Tiengo, Lina Tomasella, Martin Topinka, Damien Turpin, and Pietro Ubertini

Abstract

Magnetar giant flares are rare explosive events releasing up to 1047 erg in gamma rays in less than 1 second from young neutron stars with magnetic fields up to 1015−16 G (refs. 1,2). Only three such flares have been seen from magnetars in our Galaxy3,4 and in the Large Magellanic Cloud5 in roughly 50 years. This small sample can be enlarged by the discovery of extragalactic events, as for a fraction of a second giant flares reach luminosities above 1046 erg s−1, which makes them visible up to a few tens of megaparsecs. However, at these distances they are difficult to distinguish from short gamma-ray bursts (GRBs); much more distant and energetic (1050−53 erg) events, originating in compact binary mergers6. A few short GRBs have been proposed7–11, with different amounts of confidence, as candidate giant magnetar flares in nearby galaxies. Here we report observations of GRB 231115A, positionally coincident with the starburst galaxy M82 (ref. 12). Its spectral properties, along with the length of the burst, the limits on its X-ray and optical counterparts obtained within a few hours, and the lack of a gravitational wave signal, unambiguously qualify this burst as a giant flare from a magnetar in M82.

Published
2024

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