ADC/CDS Standard Document for Catalog:
/journal_tables/AJ/113/1001/

1. Use the ADC Data Viewer Suite to visualize the data.
2. Get the data files via anonymous FTP. (See Note.)

J/AJ/113/1001                      Stellar photometry in NGC 147 (Han+ 1997)
================================================================================
Stellar Populations in the Dwarf Elliptical Galaxy NGC 147
     Han M., Hoessel J.G., Gallagher III J.S., Holtzman J., Stetson P.B.,
     Trauger J., Ballester G.E., Burrows C., Clarke J., Crisp D.,
     Griffiths R., Grillmair C., Hester J., Krist J., Mould J.R., Scowen P.,
     Stapelfeldt K., Watson A., Westphal J.
    <Astron. J. 113, 1001 (1997)>
    =1997AJ....113.1001H
================================================================================
ADC_Keywords: Galaxies, photometry
Mission_Name: HST

Abstract:
    Deep V and I CCD images in a central and an outer field of the Local
    Group dwarf elliptical galaxy NGC 147 have been obtained with the Wide
    Field and Planetary Camera-2 (WFPC2) on board of the Hubble Space
    Telescope. The color-magnitude diagram shows a number of interesting
    features, including a well defined red giant branch (RGB), a red
    horizontal branch (HB), a strong red clump, and a small number of
    extended asymptotic giant branch (EAGB) stars. A mean distance modulus
    of (m-M)_0_=24.39 is derived based on both the HB and the RGB tip
    brightness. The metallicity [Fe/H] as determined from the RGB color
    has a mean value of -0.91 in the central field, and -1.0 in the outer
    field; and the outer field shows a weak tendency of increasing
    metallicity with galactocentric radius. A metallicity dispersion is
    also present in the galaxy, and it shows a clear radial variation in
    the sense that a larger dispersion is seen at smaller radii. The small
    population of EAGB stars indicates the presence of intermediate-aged
    (several Gyr) stars in the galaxy, while the absence of the main
    sequence stars with M_V_<1 shows that star formation ceased at least 1
    Gyr ago. The distribution of the EAGB stars indicates that the younger
    stars are more centrally concentrated than the majority of older
    stars. A similar age gradient is also implied by the relative
    distribution of the HB stars, which appear to be more populous at
    larger radii. These results are considered within the context of
    theoretical models for the evolution of dwarf elliptical galaxies.
    (Copyright) 1997 American Astronomical Society.

Objects:
    ----------------------------------------------------------
       RA   (2000)   DE    Designation(s)
    ----------------------------------------------------------
     00 33.1      +48 31   NGC 147
    ----------------------------------------------------------

File Summary:
--------------------------------------------------------------------------------
 FileName    Lrecl    Records   Explanations
--------------------------------------------------------------------------------
ReadMe          80          .   This file
table2a.dat     46      78421   NGC 147 - inner field photometry
table2b.dat     46      38203   NGC 147 - outer field photometry
--------------------------------------------------------------------------------

Byte-by-byte Description of file: table2a.dat, table2b.dat
--------------------------------------------------------------------------------
   Bytes Format  Units   Label      Explanations
--------------------------------------------------------------------------------
   1-  8  F8.2   pix     Xpos      *X pixel coordinate
  10- 16  F7.2   pix     Ypos      *Y pixel coordinate
  18- 24  F7.3   mag     Vmag       V magnitude
  26- 31  F6.3   mag   e_Vmag       Error in Vmag
  33- 39  F7.3   mag     Imag       I magnitude
  41- 46  F6.3   mag   e_Imag       Error in Imag
--------------------------------------------------------------------------------
Note on Xpos, Ypos:
  The coordinate system is defined by simply stacking up the
  contiguous fields of the 4 chips in each field (see HST/WFPC2
  Handbook v3.0), and defining the central joining point to be
  at (800,800). X and Y are in units of WF pixels.
  North is up, East left.
--------------------------------------------------------------------------------


Origin: AAS CD-ROM series, Volume 8, 1997         Lee Brotzman [ADS] 09-Apr-1997
================================================================================
(End)                                                         [CDS]  04-Jul-1997