Browsing by Author "Starling, R. L. C."

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    A NEW POPULATION OF ULTRA-LONG DURATION GAMMA-RAY BURSTS
    (IOP PUBLISHING LTD, 2014) Levan, A. J.; Tanvir, N. R.; Starling, R. L. C.; Wiersema, K.; Page, K. L.; Perley, D. A.; Schulze, S.; Wynn, G. A.; Chornock, R.; Hjorth, J.; Cenko, S. B.; Fruchter, A. S.; O'Brien, P. T.; Brown, G. C.; Tunnicliffe, R. L.; Malesani, D.; Jakobsson, P.; Watson, D.; Berger, E.; Bersier, D.; Cobb, B. E.; Covino, S.; Cucchiara, A.; de Ugarte Postigo, A.; Fox, D. B.; Gal Yam, A.; Goldoni, P.; Gorosabel, J.; Kaper, L.; Kruehler, T.; Karjalainen, R.; Osborne, J. P.; Pian, E.; Sanchez Ramirez, R.; Schmidt, B.; Skillen, I.; Tagliaferri, G.; Thoene, C.; Vaduvescu, O.; Wijers, R. A. M. J.; Zauderer, B. A.
    We present comprehensive multiwavelength observations of three gamma-ray bursts (GRBs) with durations of several thousand seconds. We demonstrate that these events are extragalactic transients; in particular, we resolve the long-standing conundrum of the distance of GRB 101225A (the "Christmas-day burst"), finding it to have a redshift z = 0.847 and showing that two apparently similar events (GRB 111209A and GRB 121027A) lie at z = 0.677 and z = 1.773, respectively. The systems show extremely unusual X-ray and optical light curves, very different from classical GRBs, with long-lasting, highly variable X-ray emission and optical light curves that exhibit little correlation with the behavior seen in the X-ray. Their host galaxies are faint, compact, and highly star-forming dwarf galaxies, typical of "blue compact galaxies." We propose that these bursts are the prototypes of a hitherto largely unrecognized population of ultra-long GRBs, which while observationally difficult to detect may be astrophysically relatively common. The long durations may naturally be explained by the engine-driven explosions of stars of much larger radii than normally considered for GRB progenitors, which are thought to have compact Wolf-Rayet progenitor stars. However, we cannot unambiguously identify supernova signatures within their light curves or spectra. We also consider the alternative possibility that they arise from the tidal disruption of stars by massive black holes and conclude that the associated timescales are only consistent with the disruption of compact stars (e. g., white dwarfs) by black holes of relatively low mass (<10(5) M-circle dot).
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    DETECTION OF THREE GAMMA-RAY BURST HOST GALAXIES AT z similar to 6
    (IOP PUBLISHING LTD, 2016) McGuire, J. T. W.; Tanvir, N. R.; Levan, A. J.; Trenti, M.; Stanway, E. R.; Shull, J. M.; Wiersema, K.; Perley, D. A.; Starling, R. L. C.; Bremer, M.; Stocke, J. T.; Hjorth, J.; Rhoads, J. E.; Curtis Lake, E.; Schulze, S.; Levesque, E. M.; Robertson, B.; Fynbo, J. P. U.; Ellis, R. S.; Fruchter, A. S.
    Long-duration gamma-ray bursts (GRBs) allow us to pinpoint and study star-forming galaxies in the early universe, thanks to their orders of magnitude brighter peak luminosities compared to other astrophysical sources, and their association with the deaths of massive stars. We present Hubble Space Telescope Wide Field Camera 3 detections of three Swift GRB host galaxies lying at redshifts z = 5.913 (GRB 130606A), z = 6.295 (GRB 050904), and z = 6.327 (GRB 140515A) in the F140W (wide-JH band, lambda(obs) similar to 1.4 mu m) filter. The hosts have magnitudes (corrected for Galactic extinction) of m(lambda obs) = 26.34(-0.16)(+0.14), 27.56(-0.22)(+0.18), and 28.30(-0.33)(+0.25) respectively. In all three cases, the probability of chance coincidence of lower redshift galaxies is less than or similar to 2%, indicating that the detected galaxies are most likely the GRB hosts. These are the first detections of high-redshift (z > 5) GRB host galaxies in emission. The galaxies have luminosities in the range 0.1-0.6 L-z=6* (with M-1600* = -20.95 +/- 0.12) and half-light radii in the range 0.6-0.9 kpc. Both their half-light radii and luminosities are consistent with existing samples of Lyman-break galaxies at z similar to 6. Spectroscopic analysis of the GRB afterglows indicate low metallicities ([M/H] less than or similar to -1) and low dust extinction (AV less than or similar to 0.1) along the line of sight. Using stellar population synthesis models, we explore the implications of each galaxy's luminosity for its possible star-formation history and consider the potential for emission line metallicity determination with the upcoming James Webb Space Telescope.
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    Observational constraints on the optical and near-infrared emission from the neutron star-black hole binary merger candidate S190814bv
    (2020) Ackley, K.; Amati, L.; Barbieri, C.; Bauer, F. E.; Benetti, S.; Bernardini, M. G.; Bhirombhakdi, K.; Botticella, M. T.; Branchesi, M.; Brocato, E.; Bruun, S. H.; Bulla, M.; Campana, S.; Cappellaro, E.; Castro-Tirado, A. J.; Chambers, K. C.; Chaty, S.; Chen, T-W; Ciolfi, R.; Coleiro, A.; Copperwheat, C. M.; Covino, S.; Cutter, R.; D'Ammando, F.; D'Avanzo, P.; De Cesare, G.; D'Elia, V; Della Valle, M.; Denneau, L.; De Pasquale, M.; Dhillon, V. S.; Dyer, M. J.; Elias-Rosa, N.; Evans, P. A.; Eyles-Ferris, R. A. J.; Fiore, A.; Fraser, M.; Fruchter, A. S.; Fynbo, J. P. U.; Galbany, L.; Gall, C.; Galloway, D. K.; Getman, F., I; Ghirlanda, G.; Gillanders, J. H.; Gomboc, A.; Gompertz, B. P.; Gonzalez-Fernandez, C.; Gonzalez-Gaitan, S.; Grado, A.; Greco, G.; Gromadzki, M.; Groot, P. J.; Gutierrez, C. P.; Heikkila, T.; Heintz, K. E.; Hjorth, J.; Hu, Y-D; Huber, M. E.; Inserra, C.; Izzo, L.; Japelj, J.; Jerkstrand, A.; Jin, Z. P.; Jonker, P. G.; Kankare, E.; Kann, D. A.; Kennedy, M.; Kim, S.; Klose, S.; Kool, E. C.; Kotak, R.; Kuncarayakti, H.; Lamb, G. P.; Leloudas, G.; Levan, A. J.; Longo, F.; Lowe, T. B.; Lyman, J. D.; Magnier, E.; Maguire, K.; Maiorano, E.; Mandel, I; Mapelli, M.; Mattila, S.; McBrien, O. R.; Melandri, A.; Michalowski, M. J.; Milvang-Jensen, B.; Moran, S.; Nicastro, L.; Nicholl, M.; Guelbenzu, A. Nicuesa; Nuttal, L.; Oates, S. R.; O'Brien, P. T.; Onori, F.; Palazzi, E.; Patricelli, B.; Perego, A.; Torres, M. A. P.; Perley, D. A.; Pian, E.; Pignata, G.; Piranomonte, S.; Poshyachinda, S.; Possenti, A.; Pumo, M. L.; Quirola-Vasquez, J.; Ragosta, F.; Ramsay, G.; Rau, A.; Rest, A.; Reynolds, T. M.; Rosetti, S. S.; Rossi, A.; Rosswog, S.; Sabha, N. B.; Carracedo, A. Sagues; Salafia, O. S.; Salmon, L.; Salvaterra, R.; Savaglio, S.; Sbordone, L.; Schady, P.; Schipani, P.; Schultz, A. S. B.; Schweyer, T.; Smartt, S. J.; Smith, K. W.; Smith, M.; Sollerman, J.; Srivastav, S.; Stanway, E. R.; Starling, R. L. C.; Steeghs, D.; Stratta, G.; Stubbs, C. W.; Tanvir, N. R.; Testa, V; Thrane, E.; Tonry, J. L.; Turatto, M.; Ulaczyk, K.; van der Horst, A. J.; Vergani, S. D.; Walton, N. A.; Watson, D.; Wiersema, K.; Wiik, K.; Wyrzykowski, L.; Yang, S.; Yi, S-X; Young, D. R.
    Context. Gravitational wave (GW) astronomy has rapidly reached maturity, becoming a fundamental observing window for modern astrophysics. The coalescences of a few tens of black hole (BH) binaries have been detected, while the number of events possibly including a neutron star (NS) is still limited to a few. On 2019 August 14, the LIGO and Virgo interferometers detected a high-significance event labelled S190814bv. A preliminary analysis of the GW data suggests that the event was likely due to the merger of a compact binary system formed by a BH and a NS.Aims. In this paper, we present our extensive search campaign aimed at uncovering the potential optical and near infrared electromagnetic counterpart of S190814bv. We found no convincing electromagnetic counterpart in our data. We therefore use our non-detection to place limits on the properties of the putative outflows that could have been produced by the binary during and after the merger.Methods. Thanks to the three-detector observation of S190814bv, and given the characteristics of the signal, the LIGO and Virgo Collaborations delivered a relatively narrow localisation in low latency - a 50% (90%) credible area of 5 deg(2) (23 deg(2)) - despite the relatively large distance of 26752 Mpc. ElectromagNetic counterparts of GRAvitational wave sources at the VEry Large Telescope collaboration members carried out an intensive multi-epoch, multi-instrument observational campaign to identify the possible optical and near infrared counterpart of the event. In addition, the ATLAS, GOTO, GRAWITA-VST, Pan-STARRS, and VINROUGE projects also carried out a search on this event. In this paper, we describe the combined observational campaign of these groups.Results. Our observations allow us to place limits on the presence of any counterpart and discuss the implications for the kilonova (KN), which was possibly generated by this NS-BH merger, and for the strategy of future searches. The typical depth of our wide-field observations, which cover most of the projected sky localisation probability (up to 99.8%, depending on the night and filter considered), is r similar to 22 (resp. K similar to 21) in the optical (resp. near infrared). We reach deeper limits in a subset of our galaxy-targeted observations, which cover a total similar to 50% of the galaxy-mass-weighted localisation probability. Altogether, our observations allow us to exclude a KN with large ejecta mass M greater than or similar to 0.1 M-circle dot to a high (> 90%) confidence, and we can exclude much smaller masses in a sub-sample of our observations. This disfavours the tidal disruption of the neutron star during the merger.Conclusions. Despite the sensitive instruments involved in the campaign, given the distance of S190814bv, we could not reach sufficiently deep limits to constrain a KN comparable in luminosity to AT 2017gfo on a large fraction of the localisation probability. This suggests that future (likely common) events at a few hundred megaparsecs will be detected only by large facilities with both a high sensitivity and large field of view. Galaxy-targeted observations can reach the needed depth over a relevant portion of the localisation probability with a smaller investment of resources, but the number of galaxies to be targeted in order to get a fairly complete coverage is large, even in the case of a localisation as good as that of this event.
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    Panning for gold, but finding helium: Discovery of the ultra-stripped supernova SN 2019wxt from gravitational-wave follow-up observations
    (2023) Agudo, I.; Amati, L.; An, T.; Bauer, F. E.; Benetti, S.; Bernardini, M. G.; Beswick, R.; Bhirombhakdi, K.; de Boer, T.; Branchesi, M.; Brennan, S. J.; Brocato, E.; Caballero-Garcia, M. D.; Cappellaro, E.; Castro Rodriguez, N.; Castro-Tirado, A. J.; Chambers, K. C.; Chassande-Mottin, E.; Chaty, S.; Chen, T. -W.; Coleiro, A.; Covino, S.; D'Ammando, F.; D'Avanzo, P.; D'Elia, V.; Fiore, A.; Floers, A.; Fraser, M.; Frey, S.; Frohmaier, C.; Fulton, M.; Galbany, L.; Gall, C.; Gao, H.; Garcia-Rojas, J.; Ghirlanda, G.; Giarratana, S.; Gillanders, J. H.; Giroletti, M.; Gompertz, B. P.; Gromadzki, M.; Heintz, K. E.; Hjorth, J.; Hu, Y. -D.; Huber, M. E.; Inkenhaag, A.; Izzo, L.; Jin, Z. P.; Jonker, P. G.; Kann, D. A.; Kool, E. C.; Kotak, R.; Leloudas, G.; Levan, A. J.; Lin, C. -C.; Lyman, J. D.; Magnier, E. A.; Maguire, K.; Mandel, I.; Marcote, B.; Sanchez, D. Mata; Mattila, S.; Melandri, A.; Michalowski, M. J.; Moldon, J.; Nicholl, M.; Guelbenzu, A. Nicuesa; Oates, S. R.; Onori, F.; Orienti, M.; Paladino, R.; Paragi, Z.; Perez-Torres, M.; Pian, E.; Pignata, G.; Piranomonte, S.; Quirola-Vasquez, J.; Ragosta, F.; Rau, A.; Ronchini, S.; Rossi, A.; Sanchez-Ramirez, R.; Salafia, O. S.; Schulze, S.; Smartt, S. J.; Smith, K. W.; Sollerman, J.; Srivastav, S.; Starling, R. L. C.; Steeghs, D.; Stevance, H. F.; Tanvir, N. R.; Testa, V.; Torres, M. A. P.; Valeev, A.; Vergani, S. D.; Vescovi, D.; Wainscost, R.; Watson, D.; Wiersema, K.; Wyrzykowski, L.; Yang, J.; Yang, S.; Young, D. R.
    We present the results from multi-wavelength observations of a transient discovered during an intensive follow-up campaign of S191213g, a gravitational wave (GW) event reported by the LIGO-Virgo Collaboration as a possible binary neutron star merger in a low latency search. This search yielded SN 2019wxt, a young transient in a galaxy whose sky position (in the 80% GW contour) and distance (similar to SIM;150 Mpc) were plausibly compatible with the localisation uncertainty of the GW event. Initially, the transient's tightly constrained age, its relatively faint peak magnitude (M-i similar to -16.7 mag), and the r-band decline rate of similar to 1 mag per 5 days appeared suggestive of a compact binary merger. However, SN 2019wxt spectroscopically resembled a type Ib supernova, and analysis of the optical-near-infrared evolution rapidly led to the conclusion that while it could not be associated with S191213g, it nevertheless represented an extreme outcome of stellar evolution. By modelling the light curve, we estimated an ejecta mass of only similar to 0.1 M circle dot, with Ni-56 comprising similar to 20% of this. We were broadly able to reproduce its spectral evolution with a composition dominated by helium and oxygen, with trace amounts of calcium. We considered various progenitor channels that could give rise to the observed properties of SN 2019wxt and concluded that an ultra-stripped origin in a binary system is the most likely explanation. Disentangling genuine electromagnetic counterparts to GW events from transients such as SN 2019wxt soon after discovery is challenging: in a bid to characterise this level of contamination, we estimated the rate of events with a volumetric rate density comparable to that of SN 2019wxt and found that around one such event per week can occur within the typical GW localisation area of O4 alerts out to a luminosity distance of 500 Mpc, beyond which it would become fainter than the typical depth of current electromagnetic follow-up campaigns.
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    The warm, the excited, and the molecular gas: GRB 121024A shining through its star-forming galaxy
    (OXFORD UNIV PRESS, 2015) Friis, M.; De Cia, A.; Kruehler, T.; Fynbo, J. P. U.; Ledoux, C.; Vreeswijk, P. M.; Watson, D. J.; Malesani, D.; Gorosabel, J.; Starling, R. L. C.; Jakobsson, P.; Varela, K.; Wiersema, K.; Drachmann, A. P.; Trotter, A.; Thoene, C. C.; de Ugarte Postigo, A.; D'Elia, V.; Elliott, J.; Maturi, M.; Goldoni, P.; Greiner, J.; Haislip, J.; Kaper, L.; Knust, F.; LaCluyze, A.; Milvang Jensen, B.; Reichart, D.; Schulze, S.; Sudilovsky, V.; Tanvir, N.; Vergani, S. D.
    We present the first reported case of the simultaneous metallicity determination of a gamma- ray burst (GRB) host galaxy, from both afterglow absorption lines as well as strong emission- line diagnostics. Using spectroscopic and imaging observations of the afterglow and host of the long- duration Swift GRB 121024A at z = 2.30, we give one of the most complete views of a GRB host/ environment to date. We observe a strong damped Lya absorber (DLA) with a hydrogen column density of log N(H i) = 21.88 +/- 0.10, H-2 absorption in the Lyman- Werner bands (molecular fraction of log(f) approximate to- 1.4; fourth solid detection of molecular hydrogen in a GRB- DLA), the nebular emission lines H alpha, H beta, [OII], [O III] and [N II], as well as metal absorption lines. We find aGRB host galaxy that is highly star forming (SFR similar to 40M circle dot yr(-1)), with a dust- corrected metallicity along the line of sight of [Zn/ H](corr) =- 0.6 +/- 0.2 ([O/H]similar to- 0.3 from emission lines), and a depletion factor [Zn/ Fe] = 0.85 +/- 0.04. The molecular gas is separated by 400 km s(-1) (and 1-3 kpc) from the gas that is photoexcited by the GRB. This implies a fairly massive host, in agreement with the derived stellar mass of log(M*/M-circle dot) = 9.9(-0.3)(+0.2). We dissect the host galaxy by characterizing its molecular component, the excited gas, and the line- emitting star- forming regions. The extinction curve for the line of sight is found to be unusually flat (R-V similar to 15). We discuss the possibility of an anomalous grain size distributions. We furthermore discuss the different metallicity determinations from both absorption and emission lines, which gives consistent results for the line of sight to GRB 121024A.