Astronomy and Astrophysics – Astrophysics
Scientific paper
2002-10-16
Astrophys.J.590:284-290,2003
Astronomy and Astrophysics
Astrophysics
16 pages. Accepted for publication in ApJ. Major changes include: comparison of the OGLE-II photometry with other data, additi
Scientific paper
10.1086/374861
Photometry of the Galactic bulge, collected during the OGLE-II microlensing search, indicates high and non-uniform interstellar extinction toward the observed fields. We use the mean I-band magnitude and V-I color of red clump stars as a tracer of interstellar extinction toward four small regions of the Galactic bulge with highly variable reddening. Similar test is performed for the most reddened region observed in the LMC. We find that the slope of the location of red clump stars in the color-magnitude diagrams (CMDs) in the Galactic bulge is significantly smaller than the slope of the reddening line following the standard extinction law (R_V=3.1) for approximations of the extinction curve by both Cardelli, Clayton and Mathis (1989, CCM89) and Fitzpatrick (1999, F99). The differences are much larger for the CCM89 approximation which, on the other hand, indicates the same slopes for the control field in the LMC, contrary to the F99 approximation. We discuss possible systematic effects that could cause the observed discrepancy. Anomalous extinction toward the Galactic bulge seems to be the most natural explanation. Our data indicate that, generally, the ratio of the total to selective absorption, R_VI, is much smaller toward the Galactic bulge than the value corresponding to the standard extinction curve (R_V=3.1). However, R_VI varies from one line-of-sight to another. Our results explain why the red clump and RR Lyr stars in the Baade's window dereddened with standard value of R_VI are redder compared to those of the local population.
No associations
LandOfFree
The Optical Gravitational Lensing Experiment. Is Interstellar Extinction Toward the Galactic Center Anomalous? does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.
If you have personal experience with The Optical Gravitational Lensing Experiment. Is Interstellar Extinction Toward the Galactic Center Anomalous?, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and The Optical Gravitational Lensing Experiment. Is Interstellar Extinction Toward the Galactic Center Anomalous? will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-569230