Interstellar extinction and the distribution of stellar populations in the direction of the ultra-deep Chandra Galactic field - Astrophysics > Astrophysics of GalaxiesReport as inadecuate




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Abstract: We studied the stellar population in the central 6.6x6.6arcmin,region of theultra-deep 1Msec Chandra Galactic field - the -Chandra bulge field- CBFapproximately 1.5 degrees away from the Galactic Center - using the HubbleSpace Telescope ACS-WFC blue F435W and red F625W images. We mainly focus onthe behavior of red clump giants - a distinct stellar population, which isknown to have an essentially constant intrinsic luminosity and color. Bystudying the variation in the position of the red clump giants on a spatiallyresolved color-magnitude diagram, we confirm the anomalous total-to-selectiveextinction ratio, as reported in previous work for other Galactic bulge fields.We show that the interstellar extinction in this area is = 4 onaverage, but varies significantly between ~3-5 on angular scales as small as 1arcminute. Using the distribution of red clump giants in anextinction-corrected color-magnitude diagram, we constrain the shape of astellar-mass distribution model in the direction of this ultra-deep Chandrafield, which will be used in a future analysis of the population of X-raysources. We also show that the adopted model for the stellar densitydistribution predicts an infrared surface brightness in the direction of the-Chandra bulge field- in good agreement i.e. within ~15% with the actualmeasurements derived from the Spitzer-IRAC observations.



Author: M. Revnivtsev 1,2,3, M. van den Berg 4, R. Burenin 2, J.E. Grindlay 4, D. Karasev 2, W. Forman 4 1 Excellence Cluster, 2 IKI, 3 v

Source: https://arxiv.org/







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