Interstellar Extinction Law toward the Galactic Center IV: J, H, and Ks Bands from VVV Red Clump Stars

Abstract

We have determined the wavelength dependence of the extinction in the near-infrared bands ($J$, $H$, $K_{\mathrm{S}}$) toward the Galactic center from the VVV (VISTA Variables in the Vía Láctea) aperture photometry of the stars in the region $|l|\lesssim 2^{\circ }.0$ and $0^{\circ }.5\lesssim |b|\lesssim 1^{\circ }.0$; this region consists of 12 VVV tiles. We have found significant systematic discrepancy up to $\sim 0.1$ mag between the stellar magnitudes of the same stars in overlapping VVV tiles. However, by carefully using the positions of red clump stars in color-magnitude diagrams as a tracer of the extinction and reddening, we are able to determine the average of the ratios of total to selective extinction to be $A(K_{\mathrm{S}})/E(H-K_{\mathrm{S}})=1.44\pm 0.04$, $A(K_{\mathrm{S}})/E(J-K_{\mathrm{S}})=0.423\pm 0.024$, $A(H)/E(J-H)=1.25\pm 0.04$; from these ratios, a steep power law $A(\lambda )\propto {\lambda }^{-\alpha }$ whose index $\alpha$ is $\sim 2.0-2.3$ in the $J,H,K_{\mathrm{S}}$ wavelength range is estimated. The obtained wavelength dependence is consistent with those obtained with the MKO photometric system employed in SIRIUS camera attached to the IRSF telescope in previous studies. Such a steep decline of extinction toward the longer wavelengths is also in line with recent results based on deep imaging surveys. The determined extinction law seems to be variable in the VVV tile to tile, and it is not clear how much of this is due to real sight line variations and due to observational systematic effects. Thus, there might be room for improvement of the extinction law determination from the existing VVV data, but this steep extinction law tends to locate heavily reddened objects in the Galactic plane more distant from us when their distance moduli are calculated from the observed reddening values.

arXiv comment14 pages, 7 figures, 2 Tables; Accepted for publication in PASJ. Some typos in the references are corrected

References in corpus (26)

• VISTA Variables in the Via Lactea (VVV): The public ESO near-IR variability survey of the Milky Way
• Reddening and Extinction Toward the Galactic Bulge from OGLE-III: The Inner Milky Way's Rv ~ 2.5 Extinction Curve
• The Mauna Kea Observatories Near-Infrared Filter Set. II. Specifications for a New JHKL'M' Filter Set for Infrared Astronomy
• VVV DR1: The First Data Release of the Milky Way Bulge and Southern Plane from the Near-Infrared ESO Public Survey VISTA Variables in the Via Lactea
• Interstellar Extinction Law toward the Galactic Center III: J, H, Ks bands in the 2MASS and the MKO systems, and 3.6, 4.5, 5.8, 8.0 micron in the Spitzer/IRAC system
• Interstellar Extinction Law in the J, H, and Ks Bands toward the Galactic Center
• Interstellar Extinction Curve Variations Toward the Inner Milky Way: A Challenge to Observational Cosmology
• The Slope of the Near Infrared Extinction Law
• The Optical Gravitational Lensing Experiment. Is Interstellar Extinction Toward the Galactic Center Anomalous?
• Mapping the Milky Way bulge at high resolution: the 3D dust extinction, CO, and X factor maps
• Extinction ratios in the inner Galaxy as revealed by the VVV survey
• GALACTICNUCLEUS: A high angular resolution $JH{K}_s$ imaging survey of the Galactic Centre. I. Methodology, performance, and near-infrared extinction towards the Galactic Centre
• Milky Way demographics with the VVV survey. IV. PSF photometry from almost one billion stars in the Galactic bulge and adjacent southern disk
• The complex, variable near infrared extinction towards the Nuclear Bulge
• Extinction law in the range 0.4-4.8 $\mu$m and the 8620 $\mathring{A}$ DIB towards the stellar cluster Westerlund 1
• Variable stars in the VVV globular clusters. I. 2MASS-GC02 and Terzan10
• A lack of classical Cepheids in the inner part of the Galactic disk
• The VVV Survey reveals classical Cepheids tracing a young and thin stellar disk across the Galaxy's bulge
• Milky Way Demographics with the VVV Survey II. Color Transformations and Near-Infrared Photometry for 136 Million Stars in the Southern Galactic Disk
• The structure behind the Galactic bar traced by red clump stars in the VVV survey
• Variations of the Selective Extinction Across the Galactic Bulge - Implications for the Galactic Bar
• Constraining Dust Extinction Properties via the VVV Survey
• Galactic Bulge Population II Cepheids in the VVV Survey: Period-Luminosity Relations and a Distance to the Galactic Center
• Discovery of a Pair of Classical Cepheids in an Invisible Cluster Beyond the Galactic Bulge
• Infrared extinction in the Inner Milky Way through the red clump giants
• New classical Cepheids in the inner part of the northern Galactic disk and their kinematics

Cited by in corpus (3)

• Observational Constraints on the Physical Properties of Interstellar Dust in the Post-Planck Era
• THEMIS 2.0: A self-consistent model for dust extinction, emission, and polarisation
• The Interstellar Medium toward the Galactic Center Source 2MASS J17470898-2829561