Changes between Initial Version and Version 1 of 2MASS_info_in_DVO

Timestamp:

Feb 24, 2009, 4:23:53 PM (17 years ago)

Author:

trac

Comment:

--

2MASS_info_in_DVO

@@ +1 @@
+=== Quick summary of the 2mass -> dvo interpretations from the 2MASS Point Source Catalog ===
+''(based on 03/10/08 emails from E. Magnier to M. Liu)''
+
+  '''ra, dec''' : obvious
+  
+  '''m'''       -> mag
+  '''cmsig'''   -> dM
+  '''msigcom''' -> dMcal (dMcal^2 + dM^2 = msigcom^2)
+  '''stdap'''   -> Map
+  '''snr'''     : skipped
+  
+  '''err_maj''' -> fhwm_x
+  '''err_min''' -> fhwm_y
+  '''err_ang''' -> angle
+  
+  '''x_scan''' -> Xccd
+  
+  '''j_psfchi''' --> psfChisq
+  
+  '''jd''' -> time is set in a fashion with DVO's understanding of time (unsigned integers, since 1970?)
+
+===  The following 2MASS values are used to set bits in the phot_flags field: ===
+
+'''''ph_qual:'''''
+
+  X = 0x0000  There is a detection at this location, but no valid 
+  brightness estimate can be extracted using any algorithm. rd_flg="9"
+  and default magnitude is null.
+
+  U = 0x0001  Upper limit on magnitude. Source is not detected in this
+  band (rd_flg="0"), or it is detected, but not resolved in a consistent 
+  fashion with other bands (rd_flg="6"). A value of ph_qual="U" does not
+  necessarily mean that there is no flux detected in this band at the
+  location. Whether or not flux has been detected can be determined from
+  the value of rd_flg. When rd_flg="0", no flux has been detected. When
+  rd_flg="6", flux has been detected at the location where the images
+  were not deblended consistently in all three bands (JHKs).
+
+  F = 0x0002  This category includes rd_flg="1" or rd_flg="3" sources
+  where a reliable estimate of the photometric error, [jhk]_cmsig, could
+  not be determined. The uncertainties reported for these sources in
+  [jhk]_cmsig and [jhk]_msigcom are flags and have numeric values >8.0.
+
+  E = 0x0003  This category includes detections where the
+  goodness-of-fit quality of the profile-fit photometry was very poor
+  (rd_flg=2 and [jhk]psf_chi>10.0), or detections where psf fit
+  photometry did not converge and an aperture magnitude is reported
+  (rd_flg=4), or detections where the number of frames was too small in
+  relation to the number of frames in which a detection was
+  geometrically possible (rd_flg="1" or rd_flg="2").
+
+  A = 0x0004  Detections in any brightness regime where valid
+  measurements were made (rd_flg="1","2" or "3") with [jhk]_snr>10 AND
+  [jhk]_cmsig<0.10857.
+
+  B = 0x0005  Detections in any brightness regime where valid
+  measurements were made (rd_flg="1","2" or "3") with [jhk]_snr>7 AND
+  [jhk]_cmsig<0.15510.
+
+  C = 0x0006  Detections in any brightness regime where valid
+  measurements were made (rd_flg="1","2" or "3") with [jhk]_snr>5 AND
+  [jhk]_cmsig<0.21714.
+
+  D = 0x0007  Detections in any brightness regime where valid
+  measurements were made (rd_flg="1","2" or "3") with no [jhk]_snr or
+  [jhk]_cmsig requirement.
+
+'''''rd_flag:'''''
+
+  0 = 0x0000  Source is not detected in this band. The default magnitude
+  is the 95% confidence upper limit derived from a 4" radius aperture
+  measurement taken at the position of the source on the Atlas Image.
+  The sky background is estimated in an annular region with inner radius
+  of 14" and outer radius of 20".
+
+  1 = 0x0010  The default magnitude is derived from aperture photometry
+  measurements on the 51 ms "Read_1" exposures. The aperture radius is
+  4", with the sky background measured in an annulus with an inner
+  radius of 14" and an outer radius of 20". Used for sources that
+  saturate one or more of the 1.3s "Read_2" exposures, but are not
+  saturated on at least one of the 51 ms "Read_1" frames.
+
+  2 = 0x0020  The default magnitude is derived from a profile-fitting
+  measurement made on the 1.3 sec "Read_2" exposures. The profile-fit
+  magnitudes are normalized to curve-of-growth-corrected aperture
+  magnitudes. This is the most common type in the PSC, and is used for
+  sources that have no saturated pixels in any of the 1.3 sec exposures.
+
+  3 = 0x0030  The default magnitude is derived from a 1-d radial profile
+  fitting measurement made on the 51 ms "Read_1" exposures. Used for
+  very bright sources that saturate all of the 51 ms "Read 1" exposures.
+
+  4 = 0x0040  The default magnitude is derived from
+  curve-of-growth-corrected 4" radius aperture photometry measurements
+  on the 1.3 s "Read_2" exposures. This is used for sources that are not
+  saturated in any of the Read_2 frames, but where the profile-fitting
+  measurements fail to converge to a solution. These magnitudes are the
+  same as the standard aperture magnitudes (j_m_stdap, h_m_stdap,
+  k_m_stdap), but when they are the default magnitudes, it generally
+  implies that they are low quality measurements.
+
+  6 = 0x0050  The default magnitude is the 95% confidence upper limit
+  derived from a 4" radius aperture measurement taken at the position of
+  the source on the Atlas Image. The sky background is estimated in an
+  annular region with inner radius of 14" and outer radius of 20". This
+  is used for pairs of sources which are detected and resolved in
+  another band, but are detected and not resolved in this band. This
+  differs from a rd_flg="0" because in this case there is a detection of
+  the source in this band, but it is not consistently resolved across
+  all bands.
+
+  9 = 0x0060  The default magnitude is the 95% confidence upper limit
+  derived from a 4" radius aperture measurement taken at the position of
+  the source on the Atlas Image. The sky background is estimated in an
+  annular region with inner radius of 14" and outer radius of 20". This
+  is used for sources that were nominally detected in this band, but
+  which could not have a useful brightness measurement from either
+  profile fitting or aperture photometry. This often occurs in highly
+  confused regions, or very near Tile edges where a significant fraction
+  of the measurement aperture of sky annulus falls off the focal plane.
+
+'''''cc_flag:'''''
+
+  p = 0x0000  Persistence. Source may be contaminated by a latent image
+  left by a nearby bright star.
+
+  c = 0x0100  Photometric Confusion. Source photometry is biased by a
+  nearby star that has contaminated the background estimation. This is
+  very common in high source density regions.
+
+  d = 0x0200  Diffraction spike confusion. Source may be contaminated by
+  a diffraction spike from a nearby star.
+
+  s = 0x0300  Electronic stripe. Source measurement may be contaminated
+  by a stripe from a nearby bright star.
+
+  b = 0x0400  Bandmerge confusion. In the process of merging detections
+  in the different bands for this source, there was more than one
+  possible match between the different band components. This occurs in
+  regions of very high source density, or when multiple sources were
+  split in one band but not another.
+
+  0 = 0x0500  Source is unaffected by known artifacts, or is not
+  detected in the band.
+
+'''''bl_flag:''''' (0,1 : not blended) anything except 0 or 1 -> 0x0008
+
+'''''gal_flag:''''' (0,1 : not extended) anything except 0 or 1 -> 0x0080
+
+'''''mp_flag:''''' anything except 0 or 1 -> 0x0800
+
+'''''dup_flag:''''' anything except 0 or 1 -> 0x1000
+
+'''''use_flag:''''' anything except 0 or 1 -> 0x2000