What is the expected depth for i-band data obtained for LS DR10?

Question

Hello again,

I'm writing a paper that makes use of LS DR10 data and would like to quote the expected 5-sigma depths of each of the bands, griz.  Within Dey et al. (2019) is the statement: "Imaging will be in three optical bands to a depth of at least g = 24.0, r = 23.4 and z = 22.5.". Also, on this page https://www.legacysurvey.org/dr10/description/#depths it says "The predicted proposed Legacy Surveys depths for 2 observations at 1.5″ seeing were =24.7

, =23.9, =23.0" (Please ignore the formatting issue!)

However, on the same page a histogram of the i-band magnitudes is also shown, but with no predicted 5-sigma depth. Please does anyone know what this value is? 

Kind regards,

Sarah

Answer 1

Hi Sarah,
Sorry for the delay in replying this.

I asked Dusting Lang, Legacy Survey mastermind, once again, about this. He said this:

"In DECaLS, we did not observe any i band, because that was not required for DESI targeting.

In addition to our own DECaLS data, we also include (almost) all publicly available archival DECam imaging.  This includes a large amount of i-band imaging from DES, and other programs such as DELVE and DeROSITAS.

The 50th percentile depths (where there is coverage), are

g band,  50-th depth percentile: 24.87
r band,  50-th depth percentile: 24.39
i band,  50-th depth percentile: 23.98
z band,  50-th depth percentile: 23.39

"
He said he calculated the i-band depth from here. 

Please let us know if this helps.
Cheers,
David

Comments

Hiya David (and Dustin),

Yes, that helps a lot -- thank you!

Best wishes,
Sarah