Peering through the veil: near-infrared photometry and extinction for the Galactic nuclear star cluster

By R. Schödel, F. Najarro, K. Mužić, A. Eckart. 2009

180 citations recorded by the source corpus.

The aims of this work are to provide accurate photometry in multiple near-infrared broadband filters, to determine the power-law index of the extinction-law toward the central parsec of the Galaxy, to provide measurements of the absolute extinction toward the Galactic center, and finally to measure the spatial variability of extinction on arcsecond scales.We use adaptive optics observations of the central parsec of the Milky Way. Absolute values for the extinction in the H, Ks, and L'-bands as well as of the power-law indices of the H to Ks and Ks to L' extinction-laws are measured based on the well-known properties of red clump stars. Extinction maps are derived based on H-Ks and Ks-L' colors. We present Ks-band photometry for ~7700 stars (H and L' photometry for a subset). From a number of recently published values we compute a mean distance of the Galactic center of R_0=8.03+-0.15 kpc, which has an uncertainty of just 2%. Based on this R_0 and on the RC method, we derive absolute mean extinction values toward the central parsec of the Galaxy of A_H=4.48+-0.13 mag, A_Ks=2.54+-0.12$ mag, and A_L'=1.27+-0.18 mag. We estimate values of the power-law indices of the extinction-law of alpha_{H-Ks}=2.21+-0.24 and alpha_{Ks-L'}=1.34+-0.29. A Ks-band extinction map for the Galactic center is computed based on this extinction law and on stellar H-Ks colors. Mean extinction values in a circular region with 0.5" radius centered on Sagittarius A* are A_{H, SgrA*}=4.35+-0.12, A_{Ks, SgrA*}=2.46+-0.03, and A_{L', SgrA*}=1.23+-0.08.

Subfields: Astronomy and Astrophysics

View Paper: https://www.semanticscholar.org/paper/84719895de5b964c428e269817bce032eb545d72

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In Astronomy and Astrophysics

1. O. Gerhard
2. R. Genzel
3. T. Alexander
4. F. Eisenhauer
5. C. Wegg
6. A. Ghez
7. R. Schödel
8. T. Ott

Citations in the corpus

• Star formation rates and efficiencies in the Galactic Centre (2017, methodology): “To account for interstellar extinction, we adopt an average K-band extinction of AK ∼ 2 mag from Figer et al. (1999b), Dutra et al. (2003) and Schödel et al. (2010), who determined the extinction for several objects within the CMZ region.”
• AN IMPROVED DISTANCE AND MASS ESTIMATE FOR SGR A* FROM A MULTISTAR ORBIT ANALYSIS (2016, methodology): “Ro additionally serves to calibrate the extinction towards the Galactic Center (e.g., Schödel et al. 2010).”
• REDDENING AND EXTINCTION TOWARD THE GALACTIC BULGE FROM OGLE-III: THE INNER MILKY WAY'S RV ∼ 2.5 EXTINCTION CURVE (2012, methodology): “…Galaxy has been subsequently confirmed with observations using Hubble Space Telescope (HST) optical filters by Revnivtsev et al. (2010), by analysis of RR Lyrae stars in OGLE-III (Pietrukowicz et al. 2012), and also in the near-IR (Nishiyama et al. 2008; Gosling et al. 2009; Schödel et al. 2010).”
• The Optical to Mid-infrared Extinction Law Based on the APOGEE, Gaia DR2, Pan-STARRS1, SDSS, APASS, 2MASS, and WISE Surveys (2019, methodology): “Schödel et al. (2010) derived α=2.21 by measuring extinction between H and K bands for RC stars.”
• Surface brightness profile of the Milky Way’s nuclear star cluster (2014, background): “In addition, many studies, in particular those at high angular resolution, were limited to regions far inside the half-light radius of the NSC (e.g., Scoville et al. 2003; Eckart et al. 1993; Genzel et al. 2003; Schödel et al. 2007).”
• LINE DERIVED INFRARED EXTINCTION TOWARD THE GALACTIC CENTER (2011, methodology): “In order to take both effects into account, we calculate the average extinction of the extinction map of Schödel et al. (2010) within the region of the ISO beam, and the flux weighted extinction within the ISO beam for the different line maps.”
• The old Nuclear Star Cluster in the Milky Way (2014, methodology): “The stellar number density distribution is constructed from NACO high-resolution images for Rbox < 20 ′′, in a similar way as in Schödel et al. (2010), from HST WFC3/IR data for 20′′ < Rbox < 66 ′′, and from VISTA-VVV data for 66′′ < Rbox < 1000 ′′.”
• STELLAR POPULATIONS IN THE CENTRAL 0.5 pc OF THE GALAXY. II. THE INITIAL MASS FUNCTION (2013, methodology): “In our case, only single band photometry is necessary since extinction maps are available from past multi-band photometry (Schödel et al. 2010).”