Intermediate-Band Surface Photometry of the Edge-on Galaxy NGC 4565

Abstract

We present a deep, 42.79 hr image of the nearby, edge-on galaxy NGC 4565 in\nthe\n Beijing-Arizona-Taipei-Connecticut (BATC) 6660A band using the large-format\nCCD system on the 0.6m Schmidt telescope at the Xinglong Station of the\nNational\n Astronomical Observatories of China (NAOC). we obtain a final image that is\ncalibrated to an accuracy of 0.02 mag in zero point, and for which we can\nmeasure galaxy surface brightness to an accuracy of 0.25 mag at a surface\nbrightness at 27.5 mag arcsec^-2 at 6660A, corresponding to a distance of 22\nkpc from the center of the disk. The integrated magnitude of NGC4565 in our\nfilter is m6660=8.99 (R magnitude of 9.1) to a surface brightness of 28 mag\narcsec-2. We analyze the faint outer parts of this galaxy using a\ntwo-dimensional model comprised of three components: an exponential thin disk,\nan exponential thick disk, and a power-law halo. A total of 12 parameters are\nincluded in our model. We determine the best values of our model parameters via\n10,000 random initial values, 3,700 of which converge to final values. The thin\ndisk and thick disk parameters we determine here are consistent with those of\nprevious studies of this galaxy. However, our very deep image permits a better\ndetermination of the power law fit to the halo, constraining this power law to\nbe between r^-3.2 and r^-4.0, with a best fit value of r^-3.88. We find the\naxis ratio of the halo to be 0.44 and its core radius to be 14.4 kpc (for an\nadopted distance of 14.5 Mpc).\n