Examinando por Autor "Vink, J. S."

Mostrando 1 - 5 de 5

Acceso Abierto
Mapping the core of the Tarantula Nebula with VLT-MUSE II. The spectroscopic Hertzsprung-Russell diagram of OB stars in NGC 2070
(EDP Sciences, 2021-04-13) Castro, N.; Crowther, P. A.; Evans, C. J.; Vink, J. S.; Puls, J.; Herrero, A.; García, M.; Selman, F. J.; Roth, M. M.; Simón Díaz, S.; Deutsche Forschungsgemeinschaft (DFG); Agencia Canaria de Investigación, Innovación y Sociedad de la Información (ACIISI); Agencia Estatal de Investigación (AEI); Castro, N. [0000-0003-0521-473X]; Vink, J. S. [0000-0002-8445-4397]
We present the spectroscopic analysis of 333 OB-type stars extracted from VLT-MUSE observations of the central 30 × 30 pc of NGC 2070 in the Tarantula Nebula on the Large Magellanic Cloud, the majority of which are analysed for the first time. The distribution of stars in the spectroscopic Hertzsprung-Russell diagram (sHRD) shows 281 stars in the main sequence. We find two groups in the main sequence, with estimated ages of 2.1 ± 0.8 and 6.2 ± 2 Myr. A subgroup of 52 stars is apparently beyond the main sequence phase, which we consider to be due to emission-type objects and/or significant nebular contamination affecting the analysis. As in previous studies, stellar masses derived from the sHRD are systematically larger than those obtained from the conventional HRD, with the differences being largest for the most massive stars. Additionally, we do not find any trend between the estimated projected rotational velocity and evolution in the sHRD. The projected rotational velocity distribution presents a tail of fast rotators that resembles findings in the wider population of 30 Doradus. We use published spectral types to calibrate the He Iλ4921/He IIλ5411 equivalent-width ratio as a classification diagnostic for early-type main sequence stars when the classical blue-visible region is not observed. Our model-atmosphere analyses demonstrate that the resulting calibration is well correlated with effective temperature.
Restringido
Observatory science with eXTP
(Springer Link, 2018-08-30) Zand, J. J. M.; Bozzo, E.; Qu, J.; Li, X. D.; Amati, L.; Chen, Y.; Donnarumma, I.; Doroshenko, V.; Drake, S. A.; Hernanz, M.; Jenke, P. A.; Baykal, A.; Cumming, A.; Miller, M. C.; Gendre, B.; McHardy, I.; Peretz, U.; Schatz, H.; Brown, E. F.; Neubert, T.; Gill, R.; Mikusincova, R.; Prescod Weinstein, C.; Shearer, A.; Campana, R.; Pacciani, L.; Götz, D.; Rodríguez, J.; Stappers, B. W.; Chambers, F.; Paul, B.; Gouiffès, C.; Rózanska, A.; Strohmayer, T. E.; Chenevez, J.; De Martino, D.; Malzac, J.; Suleimanov, V. F.; Ciolfi, R.; Tauris, T. M.; Méndez, M.; Svoboda, J.; D´aì, A.; Atteia, J. L.; Motch, C.; Thielemann, F. K.; D´Ammando, F.; Mahmoodifar, S.; Tombesi, F.; Degenaar, N.; Zingale, M.; Torres, D. F.; D´Elia, V.; Zhang, S.; Torresi, E.; Doyle, G.; Zhang, S. N.; Fan, X.; Zdziarski, A. A.; Malyshev, D.; Zane, S.; Maccarone, Thomas J.; Zampieri, L.; Zhang, X.; Yuan, F.; Stratta, G.; Yu, W.; Younes, G.; Yan, Z.; Xu, Y.; Xiong, S. L.; Sala, G.; Agudo, I.; Ballantyne, D. R.; Bianchi, S.; Brandt, S.; Cackett, E. M.; Grandi, P.; Granot, J.; Güdel, M.; Heger, A.; Heinke, C. O.; Homan, J.; Iaria, R.; Iwasawa, K.; Izzo, L.; Ji, L.; Del Santo, M.; De Pasquale, M.; Dai, Z. G.; Constantin, E.; Chernyakova, M.; Chen, L.; Casella, P.; Burderi, L.; Braga, J.; Belloni, T.; Andersson, N. A.; Osborne, Julian P.; Wilms, J.; Nardini, E.; De Rosa, A.; Behar, E.; Turriziani, S.; Altamirano, D.; Cavecchi, Y.; Di Salvo, T.; Papadakis, L. E.; Blay, P.; Vacchi, A.; Chen, Y. P.; Falanga, M.; Pérez Torres, M. A.; Bucciantini, N.; Vercellone, S.; Jin, C. C.; Ferdman, R. D.; Reig, P.; Campana, S.; Rowlinson, A.; Feroci, M.; Rodríguez Gil, P.; Lu., F.; Zhou, P.; Fraschetti, F.; Sakamoto, T.; Mehdipour, M.; Baglio, C.; Galloway, D. K.; Salvaterra, R.; Bhattacharyya, S.; Gambino, A. F.; Santagelo, A.; Longo, F.; Gandhi, P.; Schanne, S.; Liang, E. W.; Ge, M.; Shao, L.; Kunneriath, D.; Shore, S. N.; Kuiper, L.; Rossi, E. M.; Kreykenbohm, I.; Wu, X.; Komossa, S.; Linares, M.; Keek, L.; Li, G.; Kawai, N.; Kargaltsev, O.; Kalemci, E.; Kaastra, J. S.; José, J.; Jonker, P. G.; Manousakis, A.; Mignani, R. P.; Nättilä, J.; Orlandini, M.; Paolillo, M.; Vink, J. S.; Wang, J. J.; Wang, J. F.; Watts, A. L.; Weng, S.; Weinberg, N. N.; Wheatley, P. J.; Wijnands, R.; Woods, T. E.; Woosley, S. E.; Savolainen, T.; Sanna, A.; Salmi, T.; Romano, P.; Riggio, A.; Perinati, E.; Pellizzoni, A.; Paltani, Stéphane; O´Brien, P. T.; Miniutti, G.; Men, Y.; Bilous, A.; Lutovinov, A. A.; National Natural Science Foundation of China (NSFC); European Research Council (ERC); National Aeronautics and Space Administration (NASA); Agencia Estatal de Investigación (AEI); Royal Society; Strategic Priority Research Program of the Chinese Academy of Sciences; European Research Council (ERC); National Science Centre, Poland (NCN); Unidad de Excelencia Científica María de Maeztu Instituto de Ciencias del Cosmos (ICCUB), MDM-2014-0369
In this White Paper we present the potential of the enhanced X-ray Timing and Polarimetry (eXTP) mission for studies related to Observatory Science targets. These include flaring stars, supernova remnants, accreting white dwarfs, low and high mass X-ray binaries, radio quiet and radio loud active galactic nuclei, tidal disruption events, and gamma-ray bursts. eXTP will be excellently suited to study one common aspect of these objects: their often transient nature. Developed by an international Consortium led by the Institute of High Energy Physics of the Chinese Academy of Science, the eXTP mission is expected to be launched in the mid 2020s.
Acceso Abierto
The Gaia-ESO Survey: Age spread in the star forming region NGC 6530 from the HR diagram and gravity indicators
(EDP Sciences, 2019-03-26) Prisinzano, L.; Damiani, F.; Kalari, V.; Jeffries, R. D.; Bonito, R.; Micela, G.; Wright, N. James; Jackson, R. J.; Tognelli, E.; Guarcello, M. G.; Vink, Jorick S.; Klutsch, A.; Jiménez Esteban, F. M.; Roccatagliata, V.; Tautvaisilenè, G.; Gilmore, G.; Randich, S.; Alfaro, Emilio J.; Flaccomio, E.; Koposov, S.; Lanzafame, A. C.; Pancino, E.; Bergemann, M.; Carraro, G.; Franciosini, E.; Frasca, A.; Gonneau, A.; Hourihane, A.; Jofre, P.; Lewis, J.; Magrini, L.; Monaco, L.; Morbidelli, L.; Sacco, G. G.; Worley, Charlotte C.; Zaggia, S.; European Commission (EC); Leverhulme Trust; Istituto Nazionale di Astrofisica (INAF); Ministero dell'Istruzione, dell'Università e della Ricerca (MIUR); Unidad de Excelencia Científica María de Maeztu Centro de Astrobiología del Instituto Nacional de Técnica Aeroespacial y CSIC, MDM-2017-0737
Context. In very young clusters, stellar age distribution is empirical proof of the duration of star cluster formation and thus it gives indications of the physical mechanisms involved in the star formation process. Determining the amount of interstellar extinction and the correct reddening law are crucial steps to derive fundamental stellar parameters and in particular accurate ages from the Hertzsprung-Russell diagram. Aims. In this context, we seek to derive accurate stellar ages for NGC 6530, the young cluster associated with the Lagoon Nebula to infer the star formation history of this region. Methods. We used the Gaia-ESO survey observations of the Lagoon Nebula, together with photometric literature data and Gaia DR2 kinematics, to derive cluster membership and fundamental stellar parameters. Using spectroscopic effective temperatures, we analysed the reddening properties of all objects and derived accurate stellar ages for cluster members. Results. We identified 652 confirmed and 9 probable members. The reddening inferred for members and non-members allows us to distinguish foreground objects, mainly main-sequence stars, and background objects, mainly giants, and to trace the three-dimensional structure of the nebula. This classification is in agreement with the distances inferred from Gaia DR2 parallaxes for these objects. Finally, we derive stellar ages for 382 confirmed cluster members for which we obtained the individual reddening values. In addition, we find that the gravity-sensitive γ index distribution for the M-type stars is correlated with stellar age. Conclusions. For all members with Teff < 5500 K, the mean logarithmic age is 5.84 (units of years) with a dispersion of 0.36 dex. The age distribution of stars with accretion or discs, i.e. classical T Tauri stars with excess (CTTSe), is similar to that of stars without accretion and without discs, i.e. weak T Tauri stars with photospheric emission (WTTSp). We interpret this dispersion as evidence of a real age spread since the total uncertainties on age determinations, derived from Monte Carlo simulations, are significantly smaller than the observed spread. This conclusion is supported by evidence of the decrease of the gravity-sensitive γ index as a function of stellar ages. The presence of a small age spread is also supported by the spatial distribution and kinematics of old and young members. In particular, members with accretion or discs, formed in the last 1 Myr, show evidence of subclustering around the cluster centre, in the Hourglass Nebula and in the M8-E region, suggesting a possible triggering of star formation events by the O-type star ionization fronts.
Restringido
The R136 star cluster dissected with Hubble Space Telescope/STIS – II. Physical properties of the most massive stars in R136
(Oxford Academics: Oxford University Press, 2020-09-14) Bestenlehner, J. M.; Crowther, P. A.; Caballero Nieves, S. M.; Schneider, F. R. N.; Simón Díaz, S.; Brands, S. A.; De Koter, A.; Gräfener, G.; Herrero, A.; Langer, N.; Lennon, D. J.; Maíz Apellániz, J.; Puls, J.; Vink, Jorick S.; Agencia Canaria de Investigación, Innovación y Sociedad de la Información (ACIISI); Agencia Estatal de Investigación (AEI); Schneider, F. [0000-0002-5965-1022]; Bestenlehner, J. [0000-0002-0859-5139]; Caballero Nieves, S. [0000-0002-8348-5191]; Maíz Apellániz, J. [0000-0003-0825-3443]; Unidad de Excelencia Científica María de Maeztu Centro de Astrobiología del Instituto Nacional de Técnica Aeroespacial y CSIC, MDM-2017-0737; Centros de Excelencia Severo Ochoa, INSTITUTO DE ASTROFÍSICA DE CANARIAS (IAC), SEV-2015-0548
We present an optical analysis of 55 members of R136, the central cluster in the Tarantula Nebula of the Large Magellanic Cloud. Our sample was observed with STIS aboard the Hubble Space Telescope, is complete down to about 40M(circle dot), and includes seven very massive stars with masses over 100M(circle dot). We performed a spectroscopic analysis to derive their physical properties. Using evolutionary models, we find that the initial mass function of massive stars in R136 is suggestive of being top-heavy with a power-law exponent gamma approximate to 2 +/- 0.3, but steeper exponents cannot be excluded. The age of R136 lies between 1 and 2Myr with a median age of around 1.6Myr. Stars more luminous than log L/L-circle dot = 6.3 are helium enriched and their evolution is dominated by mass-loss, but rotational mixing or some other form of mixing could be still required to explain the helium composition at the surface. Stars more massive than 40 M-circle dot have larger spectroscopic than evolutionary masses. The slope of the wind-luminosity relation assuming unclumped stellar winds is 2.41 +/- 0.13 which is steeper than usually obtained (similar to 1.8). The ionizing (log Q(0) [ph/s] = 51.4) and mechanical (logL(SW) [erg/s] = 39.1) output of R136 is dominated by the most massive stars (> 100M(circle dot)). R136 contributes around a quarter of the ionizing flux and around a fifth of the mechanical feedback to the overall budget of the Tarantula Nebula. For a census of massive stars of the Tarantula Nebula region, we combined our results with the VLT-FLAMES Tarantula Survey plus other spectroscopic studies. We observe a lack of evolved Wolf-Rayet stars and luminous blue and red supergiants.
Acceso Abierto
The VLT-FLAMES Tarantula Survey
(Astronomical Science, 2020-09-01) Evans, C. J.; Lennon, D.; Langer, N.; Almeida, L.; Bartlett, E.; Bastian, N.; Bestenlehner, J. M.; Britavskiy, N.; Castro, N.; Clark, S.; Crowther, P. A.; De Koter, A.; De Mink, S.; Dufton, P. L.; Fossati, L.; García, M.; Gieles, M.; Gräfener, G.; Grin, N.; Hénault Brunet, V.; Herrero, A.; Howarth, I.; Izzard, R.; Kalari, V.; Maíz Apellániz, J.; Markova, N.; Najarro, F.; Patrick, Lee R.; Puls, J.; Ramírez Agudelo, O.; Renzo, M.; Sabín Sanjulián, C.; Sana, H.; Schneider, F.; Schootemeijer, A.; Simón Díaz, S.; Smartt, S.; Taylor, W.; Tramper, F.; Van Loon, J.; Villaseñor, J.; Vink, J. S.; Walborn, N.
The VLT-FLAMES Tarantula Survey (VFTS) was an ESO Large Programme that has provided a rich, legacy dataset for studies of both resolved and integrated populations of massive stars. Initiated in 2008 (ESO Period 82), we used the Fibre Large Array Multi Element Spectrograph (FLAMES) to observe more than 800 massive stars in the dramatic 30 Doradus star-forming region in the Large Magellanic Cloud. At the start of the survey the importance of multiplicity among high-mass stars was becoming evident, so a key feature was multi-epoch spectroscopy to detect radial-velocity shifts arising from binary motion. Here we summarise some of the highlights from the survey and look ahead to the future of the field.