Variability of the near-infrared extinction curve towards the Galactic centre

DOI: 
10.1051/0004-6361/201936322
Publication date: 
01/10/2019
Main author: 
Nogueras-Lara, F.
IAA authors: 
Nogueras-Lara, F.;Schödel, R.;Gallego-Calvente, A. T.;Gallego-Cano, E.;Shahzamanian, B.
Authors: 
Nogueras-Lara, F.;Schödel, R.;Najarro, F.;Gallego-Calvente, A. T.;Gallego-Cano, E.;Shahzamanian, B.;Neumayer, N.
Journal: 
Astronomy and Astrophysics
Refereed: 
Yes
Publication type: 
Article
Volume: 
630
Pages: 
L3
Abstract: 
Context. Due to the extreme extinction towards the Galactic centre (A<SUB>V</SUB> ̃ 30 mag), its stellar population is mainly studied in the near-infrared (NIR) regime. Therefore, a proper analysis of the NIR extinction curve is necessary to fully characterise the stellar structure and population of the inner part of the galaxy. <BR /> Aims: We studied the dependence of the extinction index (α<SUB>λ</SUB>) in the NIR on the line of sight, wavelength, and extinction. <BR /> Methods: We used the GALACTICNUCLEUS imaging survey, a high angular resolution catalogue (0.2″) for the inner part of the Galaxy in JHK<SUB>s</SUB>, and studied the spatial variation in the extinction index. We also applied two independent methods based on red clump stars to compute the extinction index between different bands and its variation with wavelength. <BR /> Results: We did not detect any significant line-of-sight or extinction variation in α within the studied region in the nuclear stellar disc. The extinction index between JH and HK<SUB>s</SUB> differs by 0.19 ± 0.05. We obtained mean values for the extinction indices α<SUB>JH</SUB> = 2.43 ± 0.03 and α<SUB>HK<SUB>s</SUB></SUB> = 2.23 ± 0.03. The dependence of the extinction index on the wavelength could explain the differences obtained for α<SUB>λ</SUB> in the literature since it was assumed constant for the NIR regime.
Database: 
ADS
SCOPUS
URL: 
https://www.scopus.com/inward/record.uri?eid=2-s2.0-85082685844&doi=10.1051%2f0004-6361%2f201936322&partnerID=40&md5=8032095e0fe5ed8f33f640b74e0dfa76
ADS Bibcode: 
2019A&A...630L...3N
Keywords: 
Galaxy: nucleus;dust;extinction;Galaxy: center;stars: horizontal-branch;Astrophysics - Solar and Stellar Astrophysics;Astrophysics - Astrophysics of Galaxies