[daip] XMOM question

[Lawrence Rudnick]

Hi Eric -  curious question. given past history, likely user error, but 
i can't find it.

Running XMOM on a (nonstandard) map with Faraday spectra along rows 
(blanked at amplitude of 1e-5). Can't understand moments 0 and 2.

   Here is the header and the moments calculated on row 483 of the 
following image:

AIPS 1: Image=A2256     (MA) Filename=A2256SA16C_R.FAMPRO.   1
AIPS 1: Magic value blanking
AIPS 1: Minimum=  10.0002            Maximum=  48.5521 MicroJY/BEAM
AIPS 1: --------------------------------------------------------------
AIPS 1: Type    Pixels   Coord value  at Pixel    Coord incr Rotat
AIPS 1: ANGLE-PAIR AXES INCONSISTENT OR PARTLY MISSING
AIPS 1: RAD/M2     801    0.000000E+00     401*   5.0000E+00 0.00
AIPS 1: RA---SIN   600    17 03 37.300     300*    -0.150000 0.00
AIPS 1: --------------------------------------------------------------
AIPS 1: Map type=NORMAL              Number of iterations=   32332
AIPS 1: Conv size=   1.40 X   1.40   Position angle=   0.00
AIPS 1: Max ext file #: HI   1    SL   3
AIPS 1: * => NOT the formal reference pixel on this axis
AIPS 1: '483_88_0.008211_-155.8096_113.8049'

XMOMNC  88
XMOM0 0.0082  guess about 23 microJy
XMOM1 -155  looks about right
XMOM2 113.8 about HWHM^2=125^2, so looks like sqrt(2nd moment)?

Following is the slice on that row.

advice welcome.  thx.  lr




following are the inputs to XMOM
AIPS 1: XMOM      Finds the moments of each row of an image
AIPS 1: Adverbs     Values                 Comments
AIPS 1: ----------------------------------------------------------------
AIPS 1: INNAME     'A2256SA16C_R'          Input image name (name)
AIPS 1: INCLASS    'FAMPRO'                Input image name (class)
AIPS 1: INSEQ         1                    Input image name (seq. #)
AIPS 1: INDISK        5                    Input image disk unit #
AIPS 1: OUTNAME    ' '                     Output image name (name)
AIPS 1: OUTSEQ        0                    Output image name (seq. #)
AIPS 1: OUTDISK       5                    Output image disk unit #.
AIPS 1: BLC        *all 0                  Bottom left corner of input
AIPS 1: TRC        *all 0                  Top right corner of input
AIPS 1: FLUX          0                    Use only data > FLUX
AIPS 1: ICUT          0                    Use only data > in abs value
AIPS 1:                                    than ICUT (> 0). Use only
AIPS 1:                                    data < in abs value than
AIPS 1:                                    ICUT (< 0.).
AIPS 1: OPTYPE     ' '                     '': blank illegal velocities
AIPS 1:                                    'MAX' do max instead of moms
AIPS 1: PBPARM     *all 0                  Beam parameters:
AIPS 1:                                    (1) Cutoff: 0 -> no PB corr
AIPS 1:                                    (2) > 0 -> Use (3)-(7)
AIPS 1:                                    (3)-(7) Beam shape
AIPS 1: BADDISK    *all 0                  Disk to avoid for scratch

-- 
+++++++++++++++++++++++++++++++++++++
Lawrence Rudnick
Distinguished Teaching Professor
Minnesota Institute for Astrophysics
School of Physics & Astronomy
University of Minnesota
116 Church St. SE
Minneapolis, MN 55455

larry at umn.edu  http://umn.edu/~larry
+++++++++++++++++++++++++++++++++++++

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