Astronomy and Astrophysics – Astrophysics
Scientific paper
1998-10-17
Astronomy and Astrophysics
Astrophysics
29 pages, Latex, AASTeX v4.0, with 7 eps figures. To appear in The Astronomical Journal, February 1999
Scientific paper
10.1086/300737
We report observations of the double nucleus of M31 with the f/48 long-slit spectrograph of the HST Faint Object Camera. We obtain a total exposure of 19,000 sec. over 7 orbits, with the 0.063-arcsec-wide slit along the line between the two brightness peaks (PA 42). A spectrum of Jupiter is used as a spectral template. The rotation curve is resolved, and reaches a maximum amplitude of ~250 km/s roughly 0.3 arcsec either side of a rotation center lying between P1 and P2, 0.16 +/- 0.05 arcsec from the optically fainter P2. We find the velocity dispersion to be < 250 km/s everywhere except for a narrow ``dispersion spike'', centered 0.06 +/- 0.03 arcsec on the anti-P1 side of P2, in which sigma peaks at 440 +/- 70 km/s. At much lower confidence, we see local disturbances to the rotation curve at P1 and P2, and an elevation in sigma at P1. At very low significance we detect a weak asymmetry in the line-of-sight velocity distribution opposite to the sense usually encountered. Convolving our V and sigma profiles to CFHT resolution, we find good agreement with the results of Kormendy & Bender (1998, preprint), though there is a 20% discrepancy in the dispersion that cannot be attributed to the dispersion spike. Our results are not consistent with the location of the maximum dispersion as found by Bacon et al. We find that the sinking star cluster model of Emsellem & Combes (1997) does not reproduce either the rotation curve or the dispersion profile. The eccentric disk model of Tremaine (1995) fares better, and can be improved somewhat by adjusting the original parameters. However, detailed modeling will require dynamical models of significantly greater realism.
Crane Philippe
Jedrzejewski Robert I.
King Ivan R.
Statler Thomas S.
No associations
LandOfFree
Stellar Kinematics of the Double Nucleus of M31 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 Stellar Kinematics of the Double Nucleus of M31, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Stellar Kinematics of the Double Nucleus of M31 will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-587346