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View Full Version : Oh No Nanette? Oh No Nonino!



trinitree88
2010-Jan-25, 09:39 PM
Contamination of LBG's at high redshift poses a tricky need for multiwavelength observations to avoid spurious cases. SEE:http://arxiv.org/PS_cache/arxiv/pdf/1001/1001.3891v1.pdf

pete

RussT
2010-Jan-26, 01:47 AM
Contamination of LBG's at high redshift poses a tricky need for multiwavelength observations to avoid spurious cases. SEE:http://arxiv.org/PS_cache/arxiv/pdf/1001/1001.3891v1.pdf

pete

Should that be LSB's...Low Surface Bright... Galaxies?

ngc3314
2010-Jan-26, 03:51 AM
Should that be LSB's...Low Surface Bright... Galaxies?

Lyman Break Galaxies, a subset of high-redshift galaxies identified by the abrupt drop in flux shortward of the Lyman limit (emitted at 912 Angstroms) caused by absorption from even small levels of neutral hydrogen within and around the galaxy. In this context, the contamination issue is whether enough of them have close apparent neighbors at smaller redshift to mimic the inferred fraction of ionizing radiation escaping the galaxies to ionize the intergalactic medium.

This montage shows the UVRI images of the brightest LBG in the original Hubble Deep Field. At its redshift, the Lyman break has redshifted past the U band, so it's completely missing in the shortest filter. This was the first effective way to select a subset of high-redshift galaxies wholesale.

http://www.astr.ua.edu/keel/galaxies/hdflbg.jpg

(I was going to show a spectrum, but somehow the forum is refusing my attachment uploads).

RussT
2010-Jan-27, 02:26 AM
Lyman Break Galaxies, a subset of high-redshift galaxies identified by the abrupt drop in flux shortward of the Lyman limit (emitted at 912 Angstroms) caused by absorption from even small levels of neutral hydrogen within and around the galaxy. In this context, the contamination issue is whether enough of them have close apparent neighbors at smaller redshift to mimic the inferred fraction of ionizing radiation escaping the galaxies to ionize the intergalactic medium.

This montage shows the UVRI images of the brightest LBG in the original Hubble Deep Field. At its redshift, the Lyman break has redshifted past the U band, so it's completely missing in the shortest filter. This was the first effective way to select a subset of high-redshift galaxies wholesale.

http://www.astr.ua.edu/keel/galaxies/hdflbg.jpg

(I was going to show a spectrum, but somehow the forum is refusing my attachment uploads).

Thanks Bill.