How do we know the distance from the supernova?

[ACG52]

Here's how it works.

 

When a supernova blows, it radiates photons in a spherical shape. As the sphere's radius increases, so does it's surface area, and so the density of the photons from the supernova decrease. Since we know how intrinsically bright the supernova is, by comparing how bright it appears, with how bright we know it to be, we can derive a ratio, with can tell us how large is the surface area of the nova's light sphere, and so can tell us what the radius is, i.e. how far away it is.

[alpha2cen]

I am sorry but I don't have such technical knowledge of antennas, receivers and amplifiers. But I would guess that the equipment needs to be different if the redshift is very large as from very distant objects and since we are able to view the cosmic microwave background radiation which have a redshift of 1089 compared to the highest observed redshift of an object with 'only' 8.6 for UDFy-38135539, I think the practical challenge lies more in measuring a more faded signal than one with a higher redshift.

 

Which direction the Local Group Galaxy is moving now? If the centre of the Galaxy is right side, which direction the Local Group is moving? Does CMB have no effect from that moving? The CMB picture, which was reported, was modified to eliminate that effect?

[Spyman]

Which direction the Local Group Galaxy is moving now? If the centre of the Galaxy is right side, which direction the Local Group is moving? Does CMB have no effect from that moving? The CMB picture, which was reported, was modified to eliminate that effect?

 

Cosmic Microwave Background Radiation

 

 

Raw CMBR data coming down from the space vehicle (i.e., WMAP) contain foreground effects that completely obscure the fine-scale structure of the Cosmic Microwave background. The fine-scale structure is superimposed on the raw CMBR data but is too small to be seen at the scale of the raw data. The most prominent of the foreground effects is the dipole anisotropy caused by the Sun's motion relative to the CMBR background. The dipole anisotropy and others due to Earth's annual motion relative to the Sun and numerous microwave sources in the galactic plane and elsewhere must be subtracted out to reveal the extremely tiny variations characterizing the fine-scale structure of the CMBR background.

http://en.wikipedia.org/wiki/Cmbr#Data_reduction_and_analysis

 

From the CMB data it is seen that our local group of galaxies (the galactic cluster that includes the Solar System's Milky Way Galaxy) appears to be moving at 627±22 km/s relative to the reference frame of the CMB (also called the CMB rest frame, or the frame of reference in which there is no motion through the CMB) in the direction of galactic longitude l = 276±3°, b = 30±3°. This motion results in an anisotropy of the data (CMB appearing slightly warmer in the direction of movement than in the opposite direction). The standard interpretation of this temperature variation is a simple velocity redshift and blueshift due to motion relative to the CMB, but alternative cosmological models can explain some fraction of the observed dipole temperature distribution in the CMB.

http://en.wikipedia.org/wiki/Cmbr#CMBR_dipole_anisotropy

 

Another reference frame is provided by the cosmic microwave background (CMB). The Milky Way is moving at 552 ± 6 km/s with respect to the photons of the CMB, toward 10.5 right ascension, −24° declination (J2000 epoch, near the center of Hydra). This motion is observed by satellites such as the Cosmic Background Explorer (COBE) and the Wilkinson Microwave Anisotropy Probe (WMAP) as a dipole contribution to the CMB, as photons in equilibrium in the CMB frame get blue-shifted in the direction of the motion and red-shifted in the opposite direction.

http://en.wikipedia.org/wiki/Milky_Way#Velocity

 

 

Hydra (constellation)

 

 

Hydra is the largest of the 88 modern constellations, measuring 1303 square degrees. It has a long history, having been included among the 48 constellations listed by the 2nd century astronomer Ptolemy. It is commonly represented as a water snake. It should not be confused with the similarly named constellation of Hydrus.

http://en.wikipedia.org/wiki/Hydra_(constellation)

[alpha2cen]

Thank you for good answer. It seems that much effort was established to obtain that picture.

Edited July 24, 2012 by alpha2cen