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I've been working on this one for a little while now, since May in fact. It's
maybe time to draw a line under it and share what I've found.
NGC 4151 is actually not one of Arp's galaxies, for some reason it does not
appear in his atlas of peculiar galaxies. However, he showed great interest in
it and it was one of the centrepieces in his arguements against distant related
redshifts.
In 1966 Arp obtained a fabulous 3 hour exposure of this galaxy through the 200".
By examining his image very closely he was drawn to the conclusion that each of
the 2 spiral arms of ngc 4151 terminated in a connected galaxy.
He obtained spectra from each galaxy and, of course, found the connected
galaxies to have much higher redshifts than ngc 4151. So his arguement was that
the low redshift galaxy was physically connected to the 2 high redshift
galaxies. Furthermore, he claimed that the Southerly spiral arm was partly made
up from very faint galaxies. Examining modern databases does indeed confirm a
great many very faint spiral galaxies visible, either within or through the
spiral arm. By examining his original plate I cannot, in all honesty, say that I
can see the connection to the 2 smaller galaxies that Halton Arp claimed to see;
in fact I`m not even sure which galaxy he is referring to in the Southern arm.
I imaged the system in May of this year and examining my image did not throw
much light on the subject. The spiral arms are extremely faint and could or
could not be connected to the small galaxies. I decided that I could add nothing
to the debate and shelved the project for a couple of months.
Halton Arp's arguements usually revolve around ejected quasars, which he again
claims are associated with relatively nearby galaxies. For whatever reasons Arp
makes no reference to any quasars near to NGC 4151. Possibly he had no spectra
from all nearby objects and was unable to identify possible quasars.
Fortunately, we have access to superb extra-galactic databases these days and I
decided to do my own search. I found at least 10 nearby quasars within a 1000
arcsec radius from ngc 4151 and they mostly all fall on a circle of about 20 arc
min radius. The 2 nearest of them to ngc 4151 are recorded on my image. Whether
they have any cosmological significance I cannot say but I list below some
relevant redshift data for the included galaxies and quasars:
Object : Type : Magnitude : redshift, z
ngc 4151 : Seyfert Galaxy : 11.9 : 0.003262
ngc 4156 : Spiral Galaxy : 14.3 : 0.022569
B1207+39 : Quasar : 20.8 : 0.615
182.507190+39.364131 : Quasar : 21.9 : 2.96182
I think the interesting feature is the way the Aladin skyplot shows how the quasars
appear to fall on a circle, just as though they have been ejected from ngc 4151 and
are travelling away from the parent galaxy.
Of course I could just be biased!
My image : 50 x 2min exposures sigma combined in AstroArt, processed in AA and
Pixinsight.
10" Newtonian / H9C ccd camera. PHD guidance using a KWIQ Guider.
Database info from Simbad and Aladin.
The origin of the dust seen in high-redshift quasars remains controversial. Observations have shown that Asymptotic Giant Branch (AGB) stars can produce significant dust in the Magellanic Clouds and the Milky Way, but it is unclear whether dust production is as prolific in the metal-poor systems that are representative of high-redshift galaxies. In metal-poor environments, models suggest that dust production should be limited by a star's initial metallicity, since metals are necessary to seed the nucleation of dust grains. Observations of AGB stars in nearby metal-poor galaxies, however, suggest that dust production may not be inhibited at low metallicity environments. DDO 68 is the best nearby analog of high-redshift galaxies, whose stellar population can be resolved using HST. Given its metal-poor environment and high star formation rate, DDO 68 provides a unique opportunity to search for dust-producing AGB stars. Successful detection of dusty AGB stars will have major implications on dust evolution models by increasing the allowable dust formation at early epochs.
Data from the Hubble Space Telescope MAST Portal. Release Date: 2025-05-16
Camera: WFC3
RED - F336M
GREEN - F139M
BLUE - F127M
Processed with FITS Liberator, PixInsight and Photoshop 2025.
Diseño de la marca Castellanos Studio. El propósito de la marca es la asesoría personalizada de imagen y la venta de joyas.
Some year-end renders from Cinema4D. The tutorials from Maxon have been excellent this year, and using them here to show what the new Pyro and cloth can do.
Cosmic Horseshoe (J1148+1930) with gravitational lensing
The center of the lens galaxy , at a redshift of 0.444, lies at (11:48:33.15 ; 19:30:03.5) of the epoch J2000. The tangential arc is a star-forming galaxy at redshift 2.381, which is strongly lensed into a nearly full Einstein ring (≈300◦ ), whose radius is around 5"
seen by HST GO 11602, WFC3 imaging in five bands {F475W, F606W, F814W, F110W, and F160W}
My color composite with JS9
30"x25" North is up
Taken in summer 2008 in the Beartooth Mountains, MT/WY. 2005 Suzuki Reno LX. My second car, and the first I had a chance to deliberately pick out myself. It brought me a great deal of joy, pride, freedom, and probably retinal damage thanks to the brightness of the paintwork!
RedShift Radio are the official radio station for Nantwich Town FC providing live commentary at home games.
João Manso, CEO da Redshift Consulting, durante a apresentação "Our Life Echoes in Cyberspace!".
Direitos de Imagem: MediaNext Professional Information