SamD
22-03-2015, 09:46 PM
Here's a quasar at redshift 5.959 (SDSS J12497+0806) that can be imaged with amateur gear.
It's about 19.1 in the visible, the limiting mag in the photo is about 19.4. It's not that far in the sky away from the more famous 3C 273.
The camera detected about 5000 photons from the quasar over 25 mins worth of luminance exposures (on an RC8). Light pollution was typical suburban skies, VMag 19.0/arcsec^2. The labels are Johnson V mags derived from the SDSS bands.
Its redshift corresponds to the light leaving the quasar when the universe age was 950 million years, and a comoving radial distance of 27.4 Glyrs, a lot more than the light-travel time of 12.8 Gyrs.
I found it in Quasars and Active Galactic Nuclei (13th Ed.) (Veron+ 2010):
http://vizier.u-strasbg.fr/viz-bin/VizieR-5?-ref=VIZ550e70a71e27&-out.add=.&-source=VII/258/vv10&recno=77793
In this catalogue its spectrum classification gives it as a confirmed BL Lac object, which probably explains why it's so bright, ie one of its relativistic jets pointing towards us. It's also not red, B-V of 0.28, which is why I imaged with a luminance filter.
It's about 19.1 in the visible, the limiting mag in the photo is about 19.4. It's not that far in the sky away from the more famous 3C 273.
The camera detected about 5000 photons from the quasar over 25 mins worth of luminance exposures (on an RC8). Light pollution was typical suburban skies, VMag 19.0/arcsec^2. The labels are Johnson V mags derived from the SDSS bands.
Its redshift corresponds to the light leaving the quasar when the universe age was 950 million years, and a comoving radial distance of 27.4 Glyrs, a lot more than the light-travel time of 12.8 Gyrs.
I found it in Quasars and Active Galactic Nuclei (13th Ed.) (Veron+ 2010):
http://vizier.u-strasbg.fr/viz-bin/VizieR-5?-ref=VIZ550e70a71e27&-out.add=.&-source=VII/258/vv10&recno=77793
In this catalogue its spectrum classification gives it as a confirmed BL Lac object, which probably explains why it's so bright, ie one of its relativistic jets pointing towards us. It's also not red, B-V of 0.28, which is why I imaged with a luminance filter.