Pallanca, C, Ferraro, FR, Lanzoni, B, Crociati, C, Saracino, S, Dalessandro, E, Origlia, L, Rich, MR, Valenti, E, Geisler, D, Mauro, F, Villanova, S, Moni Bidin, C and Beccari, G (2021) High-resolution Extinction Map in the Direction of the Strongly Obscured Bulge Fossil Fragment Liller 1*. Astrophysical Journal, 917 (2). ISSN 0004-637X

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Abstract

We used optical images acquired with the Wide Field Camera of the Advanced Camera for Surveys on board the Hubble Space Telescope and near-infrared data from Gemini Multi-conjugate Adaptive Optics System (GeMS)/Gemini South Adaptive Optics Imager (GSAOI) to construct a high-resolution extinction map in the direction of the bulge stellar system Liller 1. In spite of its appearance of a globular cluster, Liller 1 has been recently found to harbor two stellar populations with remarkably different ages, and it is the second complex stellar system with similar properties (after Terzan 5) discovered in the bulge, thus defining a new class of objects: the Bulge Fossil Fragments. Because of its location in the inner bulge of the Milky Way, very close to the Galactic plane, Liller 1 is strongly affected by large and variable extinction. The simultaneous study of both the optical and the near-infrared color–magnitude diagrams revealed that the extinction coefficient RV in the direction of Liller 1 has a much smaller value than commonly assumed for diffuse interstellar medium (RV = 2.5, instead of 3.1), in agreement with previous findings along different light paths to the Galactic bulge. The derived differential reddening map has a spatial resolution ranging from 1'' to 3'' over a field of view of about 90'' × 90''. We found that the absorption clouds show patchy substructures with extinction variations as large as δE(B − V) ∼ 0.9 mag.

Item Type:	Article
Uncontrolled Keywords:	Astronomy & Astrophysics; CLUMPS; COLORS; GALACTIC BULGE; INNER BULGE; METAL-RICH; PARAMETERS; PHOTOMETRY; Physical Sciences; RICH GLOBULAR-CLUSTERS; Science & Technology; STARS; TERZAN 5; Science & Technology; Physical Sciences; Astronomy & Astrophysics; RICH GLOBULAR-CLUSTERS; GALACTIC BULGE; METAL-RICH; INNER BULGE; TERZAN 5; PHOTOMETRY; COLORS; PARAMETERS; CLUMPS; STARS; astro-ph.GA; astro-ph.GA; astro-ph.SR; Astronomy & Astrophysics; 0201 Astronomical and Space Sciences; 0202 Atomic, Molecular, Nuclear, Particle and Plasma Physics; 0306 Physical Chemistry (incl. Structural)
Subjects:	Q Science > QB Astronomy
Divisions:	Astrophysics Research Institute
Publisher:	American Astronomical Society; IOP Publishing
SWORD Depositor:	A Symplectic
Date Deposited:	17 Oct 2022 14:03
Last Modified:	17 Oct 2022 14:15
DOI or ID number:	10.3847/1538-4357/ac0889
URI:	https://researchonline.ljmu.ac.uk/id/eprint/17866

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