High Spatial Resolution Near-Infrared Imaging of the Central Regions of M31

Abstract

view Abstract Citations (27) References (35) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS High Spatial Resolution Near-Infrared Imaging of the Central Regions of M31 Davidge, T. J. ; Rigaut, F. ; Doyon, R. ; Crampton, D. Abstract H and K images with 0.15 arc sec angular resolution are used to probe the stellar content in the central 8 arcsec of M31. A large number of stars are detected, and the majority of these have K≥17.5 and H - K colors between 0 and 1. After correcting for differences in distance and reddening, the mean locus of the M31 (K,H- K) diagram is found to be similar to the ridgelines of asymptotic giant branch stars near the Galactic Center (GC) and in Baade' s Window. Many of the same stars detected at near-infrared wavelengths are also found in archival WFPC2 F555W and F814W images; however, the HST data do not sample the reddest, most metal-rich, stars in the central M31 field because of line blanketing at wavelengths shortward of 1 μm. H and K images of a 3 × 3 arcmin field surrounding the GC are processed to simulate the appearance of this area if viewed with 0.15 arcsec resolution at the distance of M31, and it is found that the nuclear regions of the Milky Way and M31 have very different appearances, in the sense that the nuclear regions of the Milky Way are dominated by a single, compact source, whereas the center of M31 contains two sources. The broadband infrared colors of the two nuclear sources in M31, P1 and P2, are identical, suggesting that the evolutionary histories of these objects have been similar, while the stellar contents of P1 and P2, at least near the bright end, are similar to the young star cluster surrounding the GC. The combined brightness of P1 and P2 in K is comparable to that of the star-forming complex surrounding the GC. The V- K color of the region between P1 and P2 is the same as the surrounding bulge. These results are consistent with the dynamical model suggested by Tremaine (1995, M, 110, 628), and do not support models in which P1 is an accreted object. Publication: The Astronomical Journal Pub Date: June 1997 DOI: 10.1086/118421 Bibcode: 1997AJ....113.2094D Keywords: GALAXIES: INDIVIDUAL: M31; GALAXIES: STRUCTURE; GALAXIES: SPIRAL; GALAXIES: EVOLUTION full text sources ADS | data products SIMBAD (6) NED (1) MAST (1) ESA (1)