Celestial hemisphere:  Northern  ·  Constellation: Canes Venatici (CVn)  ·  Contains:  M 106  ·  NGC 4248  ·  NGC 4258
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M106 (annotated widefield), GeOK

M106 (annotated widefield)

Revision title: corrected distances

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M106 (annotated widefield), GeOK

M106 (annotated widefield)

Revision title: corrected distances

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Description

The galaxy M106 is about 31Mly away and is also known as NGC4258.  The supermassive black hole near its center is surrounded by a disk of accreting matter that generates enormous energy especially at ultraviolet and x-ray wavelengths, thought to be related to but dimmer than distant quasars.  

This image was processed using PixInsight and noise reduction techniques as taught by Jon Rista resulting in preserving many other interesting features.  Some of these features were galaxies and quasars down to about 21st magnitude and at distances of 8.6 Bly and 13.2 Bly respectively.  Most of the distant objects are quasars unless otherwise marked or obviously seen as galaxies in the image (if it's "fuzzy" think galaxy, if it's a a well defined dot think quasar unless the annotation says otherwise). 

The ImageSolver and AnnotateImage scripts in PixInsight were used to indicate some galaxies as far away as 2 Bly as shown in turquoise color.  I then manually determined the distances and annotated in white color other distant objects by using www.aladin.u-strasbg.fr/AladinLite/ as a planetarium program and selecting the Sloan Digital Sky Survey 9 (SDSS9) as sky image and the SIMBAD catalogue.  I carefully matched SIMBAD hits with my image data to determine the annotation positions of selected distant objects between "- -" marks.  For each selected object I converted the reported radial velocity (radvel) in km/s to distance by dividing the radvel by the Hubble constant H0 = 67.8 km/s/Mpc and then converting Mpc to Mly.  These distances are simplistic since I'm not prepared to get into discussions about the curvature of space-time but are consistent insofar as close galaxies are generally bigger and brighter than distant ones.  I also found two pulsars and annotated them in turquoise since they are within the Milky Way. 

In the image, the farthest objects are little more than faint accumulations of a few pixels rising out of the background noise but definitely "there," so you may need to zoom in by left clicking and dragging on the image to see those captured photons from near the beginning of this universe.

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  • M106 (annotated widefield), GeOK
    Original
  • Final
    M106 (annotated widefield), GeOK
    B

B

Title: corrected distances

Description: The new annotations include "identifier, redshift, and light travel time interpreted as light years".

The simple version of the Hubble Equation I previously used has problems at both close and very far distances above a redshift of about 0.1. The new annotations correct the long distances by inputting the redshift into the calculator found at astro.ucla.edu/~wright/CosmoCalc.html and using the default values of Hubble Constant H0=69.6, OmegaM = 0.286, and OmegaVac = 0.714. The closer distances were looked up in Wikipedia and checked in scholarly papers. The links at that website lead to a wealth of professional cosmology information - thanks Ned Wright!

Redshifts were obtained from the Simbad database using the aladin.u-strasbg.fr/AladinLite sky atlas.

As a result, the distance to the most distant quasar in this picture at redshift 3.74 was reduced from 13.2 Gly to 12 Gly. I checked the calculator by inputting a redshift of 7 and getting 13 Gly, which agrees with the recent discovery of a quasar at that distance by astronomers at the Max Plank Institute using a much bigger telescope than mine!

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M106 (annotated widefield), GeOK