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Quasars shown at 150% size
(0.43 arcsec / pixel)
Quasar |
Bmag |
(b-v) Mag |
RedShift (z) |
Distance in Billion L-Y |
A |
18.08 |
0.11 |
1.789 |
9.7 - 11.2 |
B |
16.16 |
0.32 |
1.961 |
10.0 - 11.5 |
C |
19.13 |
na |
1.674 |
9.4 - 10.9 |
D |
19.64 |
na |
1.120 |
7.9 - 9.2 |
Instrument |
12.5" RCOS @
~f/9 (2897 mm fl) 0.64 arcsec / pixel. The Zoomify image scale
is 0.64 to 3.42 arcsec / pixel. |
Mount |
Paramount ME |
Camera |
SBIG STL-11000 w/ internal filter wheel, AstroDon Gen II Filters |
Acquisition Data |
4/5/2011 to 5/7/2011
Chino Valley, AZ... with CCDAutoPilot3 & CCDSoft. AOL guided |
Exposure |
Lum 510 min (34 x 15
min, bin 1x1 (best of 56)
RGB 675 min (15 x 15
min each, bin 2x2) |
Software |
CCDSoft, CCDStack,
Photoshop CS3, Noel Carboni's actions and Russell Croman's
GradientXTerminator.
eXcalibrator
2.0-Beta for (u-g), (g-r) color balancing, using 11 stars from the
SDSS-DR7
database.
PixFix32 (pre-beta) to
repair column defects.
CCDStack to calibrate,
register, normalize, data reject, combine the sub exposures,
Selective deconvolution and LRGB combine.
PhotoShop for
non-linear stretching
and LLRGB
combine.
Noiseware Pro, a PhotoShop
plug-in. |
Comment |
North is to right,
the galaxy is rotated 75 degrees clockwise.
NGC 5701 is located in
the Constellation Virgo, at a distance of about 77 million
light-years. The nearly face on galaxy is classified as SBO-a R... a
barred spiral ringed galaxy. The galaxy has faint tightly wrapped
spiral arms connected to the bar.
Several distant galaxies are
visible through the arms. The bright galaxy, to the lower left of
NGC 5701's center, has a redshift of z = 0.04078. NGC 5701 is much
closer... at z = 0.00502.
Also seen in the image, are over 2,500 background galaxies down to magnitude
22.6 with many fainter visible. The image also contains four quasars. The most distant is at redshift z= 1.96085. This converts to 10
to 11.5 billion light-years, depending on what calculator and Hubble
constant is used.
Quasars are intense sources of X-rays as well as visible light.
The X-rays and ultraviolet radiation are often redshifted down to
visible blue light, as shown in the quasars in this image. Quasars,
located behind thick interstellar dust or with extreme redshift z
values, can appear red.
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