Examinando por Autor "Nicuesa Guelbenzu, A."
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Ítem A blast from the infant universe: the very high- z GRB 210905A(EDP Sciences, 2022-09) Rossi, A.; Frederiks, D.D.; Kann, D.A.; De Pasquale, M.; Pian, E.; Lamb, G.; D'Avanzo, P.; Izzo, L.; Levan, A.J.; Malesani, D.B.; Melandri, A.; Nicuesa Guelbenzu, A.; Schulze, S.; Strausbaugh, R.; Tanvir, N.R.; Amati, L.; Campana, S.; Cucchiara, A.; Ghirlanda, G.; Della Valle, M.; Klose, S.; Salvaterra, R.; Starling, R.L.C.; Stratta, G.; Tsvetkova, A.E.; Vergani, S.D.; D'Aì, A.; Burgarella, D.; Covino, S.; D'Elia, V.; Postigo, A. De Ugarte; Fausey, H.; Fynbo, J.P.U.; Frontera, F.; Guidorzi, C.; Heintz, K.E.; Masetti, N.; Maiorano, E.; Mundell, C.G.; Oates, S.R.; Page, M.J.; Palazzi, E.; Palmerio, J.; Pugliese, G.; Rau, A.; Saccardi, A.; Sbarufatti, B.; Svinkin, D.S.; Tagliaferri, G.; Van Der Horst, A.J.; Watson, D.J.; Ulanov, M.V.; Wiersema, K.; Xu, D.; Zhang, J.We present a detailed follow-up of the very energetic GRB 210905A at a high redshift of z = 6.312 and its luminous X-ray and optical afterglow. Following the detection by Swift and Konus-Wind, we obtained a photometric and spectroscopic follow-up in the optical and near-infrared (NIR), covering both the prompt and afterglow emission from a few minutes up to 20 Ms after burst. With an isotropic gamma-ray energy release of Eiso = 1.27−0.19+0.20 × 1054 erg, GRB 210905A lies in the top ∼7% of gamma-ray bursts (GRBs) in the Konus-Wind catalogue in terms of energy released. Its afterglow is among the most luminous ever observed, and, in particular, it is one of the most luminous in the optical at t ≳ 0.5 d in the rest frame. The afterglow starts with a shallow evolution that can be explained by energy injection, and it is followed by a steeper decay, while the spectral energy distribution is in agreement with slow cooling in a constant-density environment within the standard fireball theory. A jet break at ∼46.2 ± 16.3 d (6.3 ± 2.2 d rest-frame) has been observed in the X-ray light curve; however, it is hidden in the H band due to a constant contribution from the host galaxy and potentially from a foreground intervening galaxy. In particular, the host galaxy is only the fourth GRB host at z > 6 known to date. By assuming a number density n = 1 cm−3 and an efficiency η = 0.2, we derived a half-opening angle of 8.4 ° ±1.0°, which is the highest ever measured for a z ≳ 6 burst, but within the range covered by closer events. The resulting collimation-corrected gamma-ray energy release of ≃1 × 1052 erg is also among the highest ever measured. The moderately large half-opening angle argues against recent claims of an inverse dependence of the half-opening angle on the redshift. The total jet energy is likely too large to be sustained by a standard magnetar, and it suggests that the central engine of this burst was a newly formed black hole. Despite the outstanding energetics and luminosity of both GRB 210905A and its afterglow, we demonstrate that they are consistent within 2σ with those of less distant bursts, indicating that the powering mechanisms and progenitors do not evolve significantly with redshift.Ítem A kilonova as the electromagnetic counterpart to a gravitational-wave source(Nature Publishing Group, 2017-11) Smartt, S.J.; Chen, T.-W.; Jerkstrand, A.; Coughlin, M.; Kankare, E.; Sim, S.A.; Fraser, M.; Inserra, C.; Maguire, K.; Chambers, K.C.; Huber, M.E.; Krühler, T.; Leloudas, G.; Magee, M.; Shingles, L.J.; Smith, K.W.; Young, D.R.; Tonry, J.; Kotak, R.; Gal-Yam, A.; Lyman, J.D.; Homan, D.S.; Agliozzo, C.; Anderson, J.P.; Angus, C.R.; Ashall, C.; Barbarino, C.; Bauer, F.E.; Berton, M.; Botticella, M.T.; Bulla, M.; Bulger, J.; Cannizzaro, G.; Cano, Z.; Cartier, R.; Cikota, A.; Clark, P.; De Cia, A.; Della Valle, M.; Denneau, L.; Dennefeld, M.; Dessart, L.; Dimitriadis, G.; Elias-Rosa, N.; Firth, R.E.; Flewelling, H.; Flörs, A.; Franckowiak, A.; Frohmaier, C.; Galbany, L.; González-Gaitán, S.; Greiner, J.; Gromadzki, M.; Nicuesa Guelbenzu, A.; Gutiérrez, C.P.; Hamanowicz, A.; Hanlon, L.; Harmanen, J.; Heintz, K.E.; Heinze, A.; Hernandez, M.-S.; Hodgkin, S.T.; Hook, I.M.; Izzo, L.; James, P.A.; Jonker, P.G.; Kerzendorf, W.E.; Klose, S.; Kostrzewa-Rutkowska, Z.; Kowalski, M.; Kromer, M.; Kuncarayakti, H.; Lawrence, A.; Lowe, T.B.; Magnier, E.A.; Manulis, I.; Martin-Carrillo, A.; Mattila, S.; McBrien, O.; Müller, A.; Nordin, J.; O'Neill, D.; Onori, F.; Palmerio, J.T.; Pastorello, A.; Patat, F.; Pignata, G.; Pumo, M.L.; Prentice, S.J.; Rau, A.; Razza, A.; Rest, A.; Reynolds, T.; Roy, R.; Ruiter, A.J.; Rybicki, K.A.; Salmon, L.; Schady, P.; Schultz, A.S.B.; Schweyer, T.; Seitenzahl, I.R.; Smith, M.; Sollerman, J.; Stalder, B.; Stubbs, C.W.; Sullivan, M.; Szegedi, H.; Taddia, F.; Taubenberger, S.; Terreran, G.; Van Soelen, B.; Vos, J.; Wainscoat, R.J.; Waters, C.; Weiland, H.; Willman, M.; Wiseman, P.; Wright, D.E.; Walton, N.A.; Wyrzykowski, L.; Yaron, O.Gravitational waves were discovered with the detection of binary black-hole mergers1 and they should also be detectable from lowermass neutron-star mergers. These are predicted to eject material rich in heavy radioactive isotopes that can power an electromagnetic signal. This signal is luminous at optical and infrared wavelengths and is called a kilonova2-5. The gravitational-wave source GW170817 arose from a binary neutron-star merger in the nearby Universe with a relatively well confined sky position and distance estimate6. Here we report observations and physical modelling of a rapidly fading electromagnetic transient in the galaxy NGC 4993, which is spatially coincident with GW170817 and with a weak, short γ-ray burst7,8. The transient has physical parameters that broadly match the theoretical predictions of blue kilonovae from neutron-star mergers. The emitted electromagnetic radiation can be explained with an ejected mass of 0.04 ± 0.01 solar masses, with an opacity of less than 0.5 square centimetres per gram, at a velocity of 0.2 ± 0.1 times light speed. The power source is constrained to have a power-law slope of -1.2 ± 0.3, consistent with radioactive powering from r-process nuclides. (The r-process is a series of neutron capture reactions that synthesise many of the elements heavier than iron.) We identify line features in the spectra that are consistent with light r-process elements (atomic masses of 90-140). As it fades, the transient rapidly becomes red, and a higher-opacity, lanthanide-rich ejecta component may contribute to the emission. This indicates that neutron-star mergers produce gravitational waves and radioactively powered kilonovae, and are a nucleosynthetic source of the r-process elements. © 2017 Macmillan Publishers Limited, part of Springer Nature.Ítem Afterglow rebrightenings as a signature of a long-lasting central engine activity?: The emblematic case of GRB 100814A(2014-02) Nardini, M.; Elliott, J.; Filgas, R.; Schady, P.; Greiner, J.; Krühler, T.; Klose, S.; Afonso, P.; Kann, D.A.; Nicuesa Guelbenzu, A.; Olivares E., F.; Rau, A.; Rossi, A.; Sudilovsky, V.; Schmidl, S.Context. In the past few years the number of well-sampled optical to near-infrared (NIR) light curves of long gamma-ray bursts (GRBs) has greatly increased, particularly due to simultaneous multi-band imagers such as GROND. Combining these densely sam pled ground-based data sets with the Swift UVOT and XRT space observations unveils a much more complex afterglow evolution than what was predicted by the most commonly invoked theoretical models. GRB 100814A represents a remarkable example of these interesting well-sampled events, showing a prominent late-time rebrightening in the optical to NIR bands and a complex spectral evolution. This represents a unique laboratory to test the different afterglow emission models. Aims. Here we study the nature of the complex afterglow emission of GRB 100814A in the framework of different theoretical models. Moreover, we compare the late-time chromatic rebrightening with those observed in other well-sampled long GRBs. Methods. We analysed the optical and NIR observations obtained with the seven-channel Gamma-Ray burst Optical and Near-infrared Detector (GROND) at the 2.2 m MPG/ESO telescope together with the X-ray and UV data detected by the instruments onboard the Swift observatory. The broad-band afterglow evolution, achieved by constructing multi-instrument light curves and spectral energy distributions, is discussed in the framework of different theoretical models. Results. We find that the standard models that describe the broad-band afterglow emission within the external shock scenario fail to describe the complex evolution of GRB 100814A, and therefore more complex scenarios must be invoked. The analysis of the very well sampled broad-band light curve of GRB 100814A allowed us to deduce that models invoking late-time activity of the central engine in the observed afterglow emission are the preferred ones for all the different observed features. This late-time activity most likely has the form of a delayed reactivation of the ejecta emission process. However, a more detailed modelling of the radiative mechanisms associated with these scenarios is necessary to arrive at a firm conclusion on the nature of the optical rebrightenings that so often are detected in long GRBs.Ítem Highly luminous supernovae associated with gamma-ray bursts: I. GRB 111209A/SN 2011kl in the context of stripped-envelope and superluminous supernovae(Astronomy and Astrophysics, 2019-04-01) Kann, D. A.; Schady, P.; Olivares E., F.; Klose, S.; Rossi, A.; Perley, D. A.; Krühler, T.; Greiner, J.; Nicuesa Guelbenzu, A.; Elliott, J.; Knust, F.; Filgas, R.; Pian, E.; Mazzali, P.; Fynbo, J. P. U.; Leloudas, G.; Afonso, P. M. J.; Delvaux, C.; Graham, J. F.; Rau, A.; Schmidl, S.; Schulze, S.; Tanga, M.; Updike, A. C.; Varela, K.Context. GRB 111209A, one of the longest gamma-ray bursts (GRBs) ever observed, is linked to SN 2011kl, which is the most luminous GRB supernova (SN) detected so far. Several lines of evidence indicate that this GRB-SN is powered by a magnetar central engine. Aims. We place SN 2011kl into the context of large samples of SNe, addressing in more detail the question of whether this GRB-SN could be radioactively powered, and whether it represents an extreme version of a GRB-SN or an underluminous superluminous SN (SLSN). Methods. We modelled SN 2011kl using SN 1998bw as a template and derived a bolometric light curve including near-infrared data. We compared the properties of SN 2011kl to literature results on stripped-envelope and SLSNe. Results. A comparison in the k,- s context, i.e. comparing SN 2011kl to SN 1998bw templates in terms of luminosity and light-curve stretch, clearly shows SN 2011kl is the most luminous GRB-SN to date and is spectrally very dissimilar to other events because it is significantly bluer/hotter. Although SN 2011kl does not reach the classical luminosity threshold of SLSNe and evolves faster than any of these objects, it resembles SLSNe more than the classical GRB-associated broad-lined Type Ic SNe in several aspects. Conclusions. GRB 111209A was a very energetic event, both at early (prompt emission) and at very late (SN) times. We show in a companion publication that with the exception of the extreme duration, the GRB and afterglow parameters are in agreement with the known distributions for these parameters. SN 2011kl, on the other hand, is exceptional both in luminosity and spectral characteristics, indicating that GRB 111209A was likely not powered by a standard-model collapsar central engine, further supporting our earlier conclusions. Instead, it reveals the possibility of a direct link between GRBs and SLSNe.Ítem Identifying the host galaxy of the short GRB 100628A(EDP Sciences, 2015-11) Nicuesa Guelbenzu, A.; Klose, S.; Palazzi, E.; Greiner, J.; Michałowski, M.J.; Kann, D.A.; Hunt, L.K.; Malesani, D.; Rossi, A.; Savaglio, S.; Schulze, S.; Xu, D.; Afonso, P.M.J.; Elliott, J.; Ferrero, P.; Filgas, R.; Hartmann, D.H.; Krühler, T.; Knust, F.; Masetti, N.; Olivares, E. F.; Rau, A.; Schady, P.; Schmidl, S.; Tanga, M.; Updike, A.C.; Varela, K.We report on the results of a comprehensive observing campaign to reveal the host galaxy of the short GRB 100628A. This burst was followed by a faint X-ray afterglow but no optical counterpart was discovered. However, inside the X-ray error circle a potential host galaxy at a redshift of z = 0.102 was soon reported in the literature. If this system is the host, then GRB 100628A was the cosmologically most nearby unambiguous short burst with a measured redshift so far. We used the multi-colour imager GROND at the ESO/La Silla MPG 2.2 m telescope, ESO/VLT spectroscopy, and deep Australia Telescope Compact Array (ATCA) radio-continuum observations together with publicly available Gemini imaging data to study the putative host and the galaxies in the field of GRB 100628A. We confirm that inside the X-ray error circle the most probable host-galaxy candidate is the morphologically disturbed, interacting galaxy system at z = 0.102. The interacting galaxies are connected by a several kpc long tidal stream, which our VLT/FORS2 spectroscopy reveals strong emission lines of [O ii], [O iii], Hα and Hβ, characteristic for the class of extreme emission-line galaxies and indicative of ongoing star formation. The latter leaves open the possibility that the GRB progenitor was a member of a young stellar population. However, we indentify a second host-galaxy candidate slightly outside the X-ray error circle. It is a radio-bright, luminous elliptical galaxy at a redshift z = 0.311. With a K-band luminosity of 2 × 1011L this galaxy resembles the probable giant elliptical host of the first well-localized short burst, GRB 050509B. If this is the host, then the progenitor of GRB 100628A was a member of an old stellar population. © ESO, 2015.Ítem Multiwavelength analysis of three supernovae associated with gamma-ray bursts observed by GROND(EDP Sciences, 2015-05) Olivares, E.F.; Greiner, J.; Schady, P.; Klose, S.; Krühler, T.; Rau, A.; Savaglio, S.; Kann, D.A.; Pignata, G.; Elliott, J.; Rossi, A.; Nardini, M.; Afonso, P.M.J.; Filgas, R.; Nicuesa Guelbenzu, A.; Schmidl, S.; Sudilovsky, V.Context. After the discovery of the first connection between γ-ray bursts (GRBs) and supernovae (SNe) almost two decades ago, tens of SN-like rebrightenings have been discovered and about seven solid associations have been spectroscopically confirmed to date. Aims. We determine the luminosity, evolution, and origin of three SN rebrightenings in GRB afterglow light curves at z ∼ 0.5 along with accurate determinations of the host-galaxy extinction. We estimate physical parameters of the SN explosions, such as synthesised 56Ni mass, ejecta mass, and kinetic energy. Methods. We employ GROND optical/NIR data and Swift X-ray/UV data to estimate the host-galaxy extinction by modelling the afterglow spectral energy distribution, to determine the SN luminosity and evolution, and to construct quasi-bolometric light curves. The latter are corrected for the contribution of the NIR-bands using data available in the literature and black-body fits. We employ Arnett's analytic approach to obtain the physical parameters of the explosion. Results. The SNe 2008hw, 2009nz, and 2010ma observed by GROND exhibit 0.80, 1.15, and 1.78 times the optical (r′-band) luminosity of SN 1998bw, respectively. While SN 2009nz exhibits an evolution similar to SN 1998bw, SNe 2008hw and 2010ma show earlier peak times. The quasi-bolometric light curves (340-2200 nm) confirm the large luminosity of SN 2010ma (1.4 × 10 43 erg s-1), while SNe 2008hw and 2009nz reached a peak luminosity closer to that of SN 1998bw. The modelling indicates in 56 Ni masses of around 0.4-0.5 MO. Conclusions. By means of a very comprehensive data set, we found that the luminosity and the 56Ni mass of SNe 2008hw, 2009nz, and 2010ma resembles those of other known GRB-associated SNe. These findings strengthens previous claims of GRB-SNe being brighter than stripped-envelope SNe unaccompanied by GRBs. © ESO, 2015.Ítem The optical/NIR afterglow of GRB 111209A: Complex yet not unprecedented(EDP Sciences, 2018-09) Kann, D.A.; Schady, P.; Olivares, E.F.; Klose, S.; Rossi, A.; Perley, D.A.; Zhang, B.; Krühler, T.; Greiner, J.; Nicuesa Guelbenzu, A.; Elliott, J.; Knust, F.; Cano, Z.; Filgas, R.; Pian, E.; Mazzali, P.; Fynbo, J.P.U.; Leloudas, G.; Afonso, P.M.J.; Delvaux, C.; Graham, J.F.; Rau, A.; Schmidl, S.; Schulze, S.; Tanga, M.; Updike, A.C.; Varela, K.Context. Afterglows of gamma-ray bursts (GRBs) are simple in the most basic model, but can show many complex features. The ultra-long duration GRB 111209A, one of the longest GRBs ever detected, also has the best-monitored afterglow in this rare class of GRBs. Aims. We want to address the question whether GRB 111209A was a special event beyond its extreme duration alone, and whether it is a classical GRB or another kind of high-energy transient. The afterglow may yield significant clues. Methods. We present afterglow photometry obtained in seven bands with the GROND imager as well as in further seven bands with the Ultraviolet/Optical Telescope (UVOT) on-board the Neil Gehrels Swift Observatory. The light curve is analysed by multi-band modelling and joint fitting with power-laws and broken power-laws, and we use the contemporaneous GROND data to study the evolution of the spectral energy distribution. We compare the optical afterglow to a large ensemble we have analysed in earlier works, and especially to that of another ultra-long event, GRB 130925A. We furthermore undertake a photometric study of the host galaxy. Results. We find a strong, chromatic rebrightening event at 0.8 days after the GRB, during which the spectral slope becomes redder. After this, the light curve decays achromatically, with evidence for a break at about 9 days after the trigger. The afterglow luminosity is found to not be exceptional. We find that a double-jet model is able to explain the chromatic rebrightening. The afterglow features have been detected in other events and are not unique. Conclusions. The duration aside, the GRB prompt emission and afterglow parameters of GRB 111209A are in agreement with the known distributions for these parameters. While the central engine of this event may differ from that of classical GRBs, there are multiple lines of evidence pointing to GRB 111209A resulting from the core-collapse of a massive star with a stripped envelope. © 2018 ESO.