XSC -- Virgo Galaxy Cluster:
Low Resolution, 50 deg2 Large Mosaic

In order to test the XSC completeness on a much larger scale, we employ a large mosaic with low spatial resolution:

a. Results

The Virgo mosaic was split into 99 pieces, each 800X800 pixels (approximately 40 arcmin on a side). The database extended sources were marked with blue circles, and the XSC sources with green circles. The sub-images were then visually inspected, concentrating on clearly delineated Virgo galaxies that are not in the XSC (i.e., source not circled in green). These sources (denoted with red circles) represent incompleteness in the XSC. The following table presents the 11X9 grid of sub-images with additional "zoom" images of galaxies missing from the XSC. (things to note: "chaff" in proximity to large and bright galaxies is mostly eliminated from the XSC; artifacts from bright stars; airglow and background gradients; source confusion; faint or compact sources provide little if any information for this experiment)

- 1 2 3 4 5 6 7 8 9 10 11
1 panel panel
Galaxy#1
Galaxy#2
panel panel panel
Galaxy#1
panel panel panel panel
Galaxy#1 		panelpanel
2 panel
Galaxy#1
panel panel panel
Galaxy#1 		panel
Galaxy#1 		panel
Galaxy#1 		panel panel
Galaxy#1 		panel panelpanel
Galaxy#1
3 panel panel
Galaxy#1
Galaxy#2 		panel
Galaxy#1 		panel
Galaxy#1 		panel panel
Galaxy#1 		panel
Galaxy#1 		panel
Galaxy#1 		panel panelpanel
4 panel
NGC4633 		panel
Galaxy#1 		panel
Galaxy#1 		panel
Galaxy#1 		panel
Galaxy#1 		panel panel
VCC991 		panel panel
Galaxy#1
Galaxy#2 		panel
Galaxy#1 		panel
5 panel panel panel
Galaxy#1 		panel
Galaxy#1
Galaxy#2 		panel panel panel
Galaxy#1
Galaxy#2 		panel
Galaxy#1
Galaxy#2 		panel panelpanel
Galaxy#1
Galaxy#2
6 panel
Galaxy#1 		panel panel panel panel
IC3457
IC3475
VCC1389 		panel
IC3388
Galaxy#2 		panel
VCC1069
vcc928 		panel panel panelpanel
7 panel panel
VCC1886 		panel
VCC1711 		panel panel panel panel panel panel panel
IC3105 		panel
8 panel
VCC1921
VCC1991 		panel
IC3665 		panel panel panel panel panel panel
VCC788 		panel panelpanel
9 panel
VCC1948 		panel
IC3647 		panel
IC3578 		panel
VCC1647 		panel
IC3490 		panel panel
IC3371
VCC949 		panel panel panelpanel
IC3074

b. Missing Sources

The following table lists the sources identified from the Virgo mosaic that do not have an XSC counterpart. Table: (ip,jp) == panel number; (x,y) = pixel coordinates; (ra,dec) == equatorial coordinates; (radius) == circular radius in arcsec; (mag, msig) == J mag & rms; (gif) == zoomed image.

Bottom Line: Most of the missing galaxies are low surface brightness, with SNRs well below the Level-1 science requirements. With regard to clearly delineated galaxies (well extended, diameters > 10-20"), the XSC completeness in VIRGO is comfortably satisfied.

IP JP x y ra dec radius ba pa ib mag msig gif image
2 1 1574.0 6789.0 189.89700 16.09676 10.0 1.000 0.0 j 10.602 0.017 gif virgo_J2.fits
2 1 1011.0 6611.0 190.38402 15.94341 10.0 1.000 0.0 j 15.303 0.531 gif virgo_J2.fits
5 1 3271.0 6687.0 188.42320 16.02272 10.0 1.000 0.0 j 12.536 0.044 gif virgo_J2.fits
9 1 6851.0 7020.0 185.31224 16.29564 10.0 1.000 0.0 j 11.401 0.021 gif virgo_J2.fits
1 2 765.0 5968.0 190.58885 15.40313 10.0 1.000 0.0 j 10.759 0.017 gif virgo_J2.fits
4 2 2993.0 6186.0 188.66069 15.60322 10.0 1.000 0.0 j 14.414 0.235 gif virgo_J2.fits
5 2 3233.0 5663.0 188.45021 15.16779 30.0 1.000 0.0 j 10.960 0.033 gif virgo_J2.fits
5 2 3233.0 5663.0 188.45021 15.16779 30.0 1.000 0.0 j 10.960 0.033 gif virgo_J2.fits
6 2 4043.0 6335.0 187.75063 15.73193 20.0 1.000 0.0 j 13.771 0.261 gif virgo_J2.fits
8 2 6062.0 5873.0 186.00397 15.34307 10.0 1.000 0.0 j 11.494 0.022 gif virgo_J2.fits
11 2 8577.0 6120.0 183.82355 15.52952 10.0 1.000 0.0 j 10.812 0.017 gif virgo_J2.fits
2 3 1046.0 5122.0 190.33504 14.70030 20.0 1.000 0.0 j 13.029 0.132 gif virgo_J2.fits
2 3 1340.0 5136.0 190.08134 14.71495 20.0 1.000 0.0 j 13.335 0.175 gif virgo_J2.fits
3 3 2365.0 5156.0 189.19589 14.74003 10.0 1.000 0.0 j 14.758 0.322 gif virgo_J2.fits
4 3 2933.0 5435.0 188.70737 14.97699 10.0 1.000 0.0 j 11.185 0.019 gif virgo_J2.fits
6 3 4406.0 5488.0 187.43617 15.02460 10.0 1.000 0.0 j 14.632 0.287 gif virgo_J2.fits
7 3 5551.0 5403.0 186.44835 14.95258 10.0 1.000 0.0 j 14.185 0.190 gif virgo_J2.fits
8 3 5951.0 5550.0 186.10144 15.07395 10.0 1.000 0.0 j 14.456 0.244 gif virgo_J2.fits
1 4 669.0 4715.0 190.65535 14.35658 30.0 1.000 0.0 j 12.044 0.082 gif virgo_J2.fits
2 4 867.0 4013.0 190.47626 13.77326 20.0 1.000 0.0 j 13.056 0.135 gif virgo_J2.fits
3 4 1871.0 4364.0 189.61604 14.07648 10.0 1.000 0.0 j 14.797 0.334 gif virgo_J2.fits
4 4 2673.0 4238.0 188.92514 13.97610 10.0 1.000 0.0 j 16.289 1.317 gif virgo_J2.fits
5 4 3942.0 4398.0 187.83443 14.11453 20.0 1.000 0.0 j 13.147 0.147 gif virgo_J2.fits
7 4 5117.0 4438.0 186.82368 14.14832 10.0 1.000 0.0 j 9.619 0.015 gif virgo_J2.fits
9 4 7050.0 4786.0 185.15776 14.43055 10.0 1.000 0.0 j 10.427 0.016 gif virgo_J2.fits
9 4 6687.0 4716.0 185.47018 14.37450 10.0 1.000 0.0 j 11.664 0.024 gif virgo_J2.fits
10 4 7519.0 4253.0 184.75838 13.98232 20.0 1.000 0.0 j 13.552 0.213 gif virgo_J2.fits
3 5 2367.0 3381.0 189.18237 13.25933 20.0 1.000 0.0 j 11.469 0.035 gif virgo_J2.fits
4 5 2877.0 3742.0 188.74702 13.56346 10.0 1.000 0.0 j 12.157 0.033 gif virgo_J2.fits
4 5 2434.0 3836.0 189.12794 13.63930 10.0 1.000 0.0 j 15.003 0.403 gif virgo_J2.fits
7 5 5229.0 3739.0 186.72859 13.56505 10.0 1.000 0.0 j 14.515 0.258 gif virgo_J2.fits
7 5 5543.0 3299.0 186.46030 13.19734 10.0 1.000 0.0 j 14.779 0.328 gif virgo_J2.fits
8 5 6194.0 3647.0 185.90085 13.48533 10.0 1.000 0.0 j 10.377 0.016 gif virgo_J2.fits
8 5 5625.0 3335.0 186.38992 13.22715 10.0 1.000 0.0 j 14.781 0.329 gif virgo_J2.fits
11 5 8524.0 3829.0 183.89851 13.61878 10.0 1.000 0.0 j 14.737 0.316 gif virgo_J2.fits
11 5 8723.0 3643.0 183.72972 13.46134 20.0 1.000 0.0 j 13.856 0.282 gif virgo_J2.fits
1 6 681.0 2418.0 190.61783 12.43990 10.0 1.000 0.0 j 15.155 0.464 gif virgo_J2.fits
5 6 3787.0 2651.0 187.96327 12.65685 20.0 1.000 0.0 j 13.182 0.152 gif virgo_J2.fits
5 6 3547.0 2789.0 188.16890 12.77129 30.0 1.000 0.0 j 12.976 0.190 gif virgo_J2.fits
5 6 3782.0 2441.0 187.96704 12.48164 10.0 1.000 0.0 j 14.451 0.243 gif virgo_J2.fits
6 6 4141.0 2632.0 187.66058 12.64171 10.0 1.000 0.0 j 11.172 0.019 gif virgo_J2.fits
7 6 4882.0 2938.0 187.02690 12.89728 10.0 1.000 0.0 j 14.686 0.301 gif virgo_J2.fits
6 6 4777.0 2850.0 187.11679 12.82392 10.0 1.000 0.0 j 13.853 0.141 gif virgo_J2.fits
7 6 5305.0 2479.0 186.66576 12.51382 10.0 1.000 0.0 j 14.278 0.207 gif virgo_J2.fits
2 7 916.0 2183.0 190.41440 12.24731 20.0 1.000 0.0 j 13.628 0.229 gif virgo_J2.fits
3 7 2171.0 2217.0 189.34230 12.28696 20.0 1.000 0.0 j 13.936 0.304 gif virgo_J2.fits
10 7 7967.0 2346.0 184.39139 12.38756 30.0 1.000 0.0 j 13.547 0.320 gif virgo_J2.fits
1 8 168.0 911.0 191.03928 11.17695 20.0 1.000 0.0 j 13.955 0.309 gif virgo_J2.fits
8 8 5713.0 1393.0 186.32016 11.60663 10.0 1.000 0.0 e 14.832 0.344 gif virgo_J2.fits
1 9 509.0 314.0 190.74284 10.68192 10.0 1.000 0.0 j 14.817 0.340 gif virgo_J2.fits
2 9 1119.0 59.0 190.22218 10.47653 30.0 1.000 0.0 j 13.664 0.357 gif virgo_J2.fits
3 9 2369.0 796.0 189.16568 11.10242 20.0 1.000 0.0 j 13.709 0.246 gif virgo_J2.fits
4 9 2578.0 595.0 188.98608 10.93676 20.0 1.000 0.0 j 14.755 0.645 gif virgo_J2.fits
5 9 3376.0 581.0 188.30785 10.92808 10.0 1.000 0.0 j 15.073 0.430 gif virgo_J2.fits
7 9 5101.0 504.0 186.84235 10.86667 20.0 1.000 0.0 j 12.302 0.069 gif virgo_J2.fits
7 9 5236.0 264.0 186.72801 10.66521 30.0 1.000 0.0 j 13.658 0.355 gif virgo_J2.fits
11 9 8516.0 331.0 183.94168 10.70014 30.0 1.000 0.0 j 13.580 0.330 gif virgo_J2.fits

The following images show some of the largest Virgo galaxies missing from the XSC. The images belong to the 2MASS Large Galaxy Atlas (LGA), and the integrated fluxes come from the LGA. Note that even these "large" examples are low surface brightness.

NGC 4523
Image size = 4.8X4.8 arcmin
Isophotal size and mags (r, J, H, Ks): 25.5", 13.014 0.049, 12.392 0.074, 12.155 0.086

NGC 4633

Image size = 3.9X3.9 arcmin
Isophotal size and mags (r, J, H, Ks): 30.8", 12.234 0.032, 11.573 0.043, 11.382 0.054

IC 3074

Image size = 3.9X3.9 arcmin
Isophotal size and mags (r, J, H, Ks): 21.2", 13.914 0.091, 13.396 0.121, 12.984 0.160

c. Future Work

Use the full-resolution (1" pixel) mosaic of the "heart of Virgo" (approximately 1.4 X 1.4 deg) to investigate the completeness of the fainter, more compact population. Here it would be useful to overlay existing catalogs (via NED) to gleen the maximum sensitivity of the 2MASS images.

[Last Updated: 2002 Oct 9 ; by Tom Jarrett]