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| DOI | 10.3847/1538-4357/AB9ABE | ||||
| Año | 2020 | ||||
| Tipo | artículo de investigación |
Citas Totales
Autores Afiliación Chile
Instituciones Chile
% Participación
Internacional
Autores
Afiliación Extranjera
Instituciones
Extranjeras
We present a narrowband imaging survey of the Large Magellanic Cloud (LMC), designed to isolate the Cii lambda lambda 7231, 7236 emission lines in objects as faint asm(lambda 7400) similar to 18. The work is motivated by the recent serendipitous discovery in the LMC of the first confirmed extragalactic [WC11] star, whose spectrum is dominated by Ciiemission, and the realization that the number of such objects is currently largely unconstrained. The survey, which imaged similar to 50 deg(2)using on-band and off-band filters, will significantly increase the total census of these rare stars. In addition, each new LMC [WC] star has a known luminosity, a quantity quite uncertain in the Galactic sample. Multiple known Ciiemitters were easily recovered, validating the survey design. We find 38 new Ciiemission candidates; spectroscopy of the complete sample will be needed to ascertain their nature. In a preliminary spectroscopic reconnaissance, we observed three candidates, finding Ciiemission in each. One is a new [WC11]. Another shows both the narrow Ciiemission lines characteristic of a [WC11], but also broad emission of Civ, Ov, and Heiicharacteristic of a much hotter [WC4] star; we speculate that this is a binary [WC]. The third object shows weak Ciiemission, but the spectrum is dominated by a dense thicket of strong absorption lines, including numerous Oiitransitions. We conclude it is likely an unusual hot, hydrogen-poor post-AGB star, possibly in transition from [WC] to white dwarf. Even lacking a complete spectroscopic program, we can infer that late [WC] stars do not dominate the central stars of LMC planetary nebulae, and that the detected Ciiemitters are largely of an old population.
| Ord. | Autor | Género | Institución - País |
|---|---|---|---|
| 1 | Margon, Bruce | Hombre |
Univ Calif Santa Cruz - Estados Unidos
University of California, Santa Cruz - Estados Unidos |
| 2 | Massey, Phil | Hombre |
Lowell Observ - Estados Unidos
No Arizona Univ - Estados Unidos Lowell Observatory - Estados Unidos Northern Arizona University - Estados Unidos |
| 3 | Neugent, Kathryn F. | Mujer |
Lowell Observ - Estados Unidos
UNIV WASHINGTON - Estados Unidos Lowell Observatory - Estados Unidos University of Washington, Seattle - Estados Unidos University of Washington - Estados Unidos |
| 4 | MORRELL, NIDIA IRENE | Mujer |
Observatorio Las Campanas - Chile
Las Campanas Observatory - Chile Carnegie Observ - Chile |
| Fuente |
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| National Science Foundation |
| Mt. Cuba Astronomical Foundation |
| National Science Foundation (NSF) |
| Directorate for Education and Human Resources |
| NSF IGERT grant |
| Agradecimiento |
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| We thank the Mt. Cuba Astronomical Foundation for their generous support, which enabled purchase of the interference filters. We are also grateful to the anonymous referee for useful comments which have improved the manuscript, to Rob Fesen for discussions about modern interference filters, and to Dick Stewart of Chroma Technology for his help with our unique specifications. We thank Dick Joyce and George Jacoby for their assistance in characterizing the delivered filters. Useful correspondence with John Hillier, Thomas Kupfer, George Jacoby, and Howard Bond is also acknowledged. We are grateful to Nigel Hambly for supplying the SuperCOSMOS images. This work was supported by the National Science Foundation (NSF) under AST-1612874, and NSF IGERT grant DGE-1258485. This work has made use of data from the European Space Agency (ESA) mission Gaia (https://www.cosmos.esa.int/gaia), processed by the Gaia Data Processing and Analysis Consortium (DPAC,.https://www.cosmos.esa.int/web/gaia/dpac/consortium).Funding for the DPAC has been provided by national institutions, in particular the institutions participating in the Gaia Multilateral Agreement. The observations reported here were possible thanks excellent support from the LCO technical and support staff. We thank Ian Thompson and Leopoldo Infante for enabling the Swope observing time. As is the case at most ground-based observatories, operations at LCO are currently suspended due to the COVID-19 crisis. We look forward to the next time we can be together again. |