GALACTICNUCLEUS: A high-angular-resolution JHKs imaging survey of the Galactic centre III. Evidence for wavelength dependence of the extinction curve in the near-infrared

Autor: Banafsheh Shahzamanian, Nadine Neumayer, A. T. Gallego-Calvente, Francisco Nogueras-Lara, E. Gallego-Cano, Francisco Najarro, Rainer Schödel
Přispěvatelé: Nogueras Lara, F. [0000-0002-6379-7593], Schödel, R. [0000-0001-5404-797X], Neumayer, N. [0000-0002-6922-2598], Gallego Cano, E. [0000-0002-7452-1496], Shahzamanian, B. [0000-0001-6437-6806], Gallego Calvente, A. T. [0000-0002-6428-8045], Najarro, F. [0000-0002-9124-0039], European Union’s Seventh Framework Programme, ERC grant, La Silla Paranal Observatory, DFG, The Milky Way System, Centro de Excelencia Científica Severo Ochoa Instituto de Astrofísica de Andalucía, MCIU/AEI/FEDER, Unidad de Excelencia Científica María de Maeztu Centro de Astrobiología del Instituto Nacional de Técnica Aeroespacial y CSIC, Ministerio de Economía y Competitividad (MINECO), European Research Council, German Research Foundation, Ministerio de Ciencia, Innovación y Universidades (España), European Commission, Ministerio de Economía y Competitividad (España), Centros de Excelencia Severo Ochoa, INSTITUTO DE ASTROFISICA DE ANDALUCIA (IAA), SEV-2017-0709, Unidad de Excelencia Científica María de Maeztu Centro de Astrobiología del Instituto Nacional de Técnica Aeroespacial y CSIC, MDM-2017-0737, Agencia Estatal de Investigación (AEI), Deutsche Forschungsgemeinschaft (DFG), European Commission (EC)
Rok vydání: 2020
Předmět:
Zdroj: DIGITAL.INTA Repositorio Digital del Instituto Nacional de Técnica Aeroespacial
Instituto Nacional de Técnica Aeroespacial (INTA)
Digital.CSIC. Repositorio Institucional del CSIC
instname
DOI: 10.48550/arxiv.2007.04401
Popis: Open Access article, published by EDP Sciences, under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.-- Open Access funding provided by Max Planck Society.
Context. The characterisation of the extinction curve in the near-infrared (NIR) is fundamental to analysing the structure and stellar population of the Galactic centre (GC), whose analysis is hampered by the extreme interstellar extinction (AV ~ 30 mag) that varies on arc-second scales. Recent studies indicate that the behaviour of the extinction curve might be more complex than previously assumed, pointing towards a variation of the extinction curve as a function of wavelength. Aims. We aim to analyse the variations of the extinction index, α, with wavelength, line-of-sight, and absolute extinction, extending previous analyses to a larger area of the innermost regions of the Galaxy. Methods. We analysed the whole GALACTICNUCLEUS survey, a high-angular resolution (~0.2″) JHKs NIR survey specially designed to observe the GC in unprecedented detail. It covers a region of ~6000 pc2, comprising fields in the nuclear stellar disc, the inner bulge, and the transition region between them. We applied two independent methods based on red clump (RC) stars to constrain the extinction curve and analysed its variation superseding previous studies. Results. We used more than 165 000 RC stars and increased the size of the regions analysed significantly to confirm that the extinction curve varies with the wavelength. We estimated a difference Δα = 0.21 ± 0.07 between the obtained extinction indices, αJH = 2.44 ± 0.05 and αHKs = 2.23 ± 0.05. We also concluded that there is no significant variation of the extinction curve with wavelength, with the line-of-sight or the absolute extinction. Finally, we computed the ratios between extinctions, AJ/AH = 1.87 ± 0.03 and AH/AKs = 1.84 ± 0.03, consistent with all the regions of the GALACTICNUCLEUS catalogue. © F. Nogueras-Lara et al. 2020.
The research leading to these results has received funding from the European Research Council under the European Union’s Seventh Framework Programme (FP7/2007-2013) / ERC grant agreement n◦ [614922]. This work is based on observations made with ESO Telescopes at the La Silla Paranal Observatory under programmes IDs 195.B-0283 and 091.B-0418. We thank the staff of ESO for their great efforts and helpfulness. F.N.-L. and N.N. gratefully acknowledge support by the Deutsche Forschungsgemeinschaft (DFG, German Research Foundation) – Project-ID 138713538 – SFB 881 (“The Milky Way System”, subproject B8). R.S., A.T.G.-C., E.G.-C., and B.S. acknowledge financial support from the State Agency for Research of the Spanish MCIU through the “Center of Excellence Severo Ochoa” award for the Insti-tuto de Astrofísica de Andalucía (SEV-2017-0709). A.T. G.-C., B.S., and R.S. acknowledge financial support from national project PGC2018-095049-B-C21 (MCIU/AEI/FEDER, UE). F.N. acknowledges financial support through Spanish grant ESP2017-86582-C4-1-R (MINECO/FEDER) and from the Spanish State Research Agency (AEI) through the Unidad de Excelencia “María de Maeztu” -Centro de Astrobiología (CSIC-INTA) project No. MDM-2017-0737.
Databáze: OpenAIRE
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