Dear all,
I wonder if there is an estimate of the magnitude depth (the usual five sigma values) for each filter expected for DR1.
Looking at the documentation, I can find only the single visit depth and the final ten years’ depths.
Hi @xPecax, thanks so much for posting that question here.
Usually when I want the 5-sigma limiting magnitudes for any year of LSST, I estimate them using Equation 6 in Section 3.2 of Ivezić et al. (2019).
The t_vis factor, the cumulative exposure time, can be estimated for any year based on the expectation that after 10 years, the mean number of visits will be 56, 80, 184, 184, 160, 160 in ugrizy filters (Table 1 of that paper). I generally assume they will all be 30-second visits, and that they will divided equally among years, such that there would be 5, 8, 18, 18, 16, 16 visits after year 1. I think the other factors in Equation 6 are all provided in that paper.
However, see also the updated estimates for the filter visit distribution from more recent simulations of the LSST observing strategy, i.e., Table 4 in the Rubin Project Science Tech Note 054, which are 56 74 184 187 166 171.
If you have any more questions please reply in this thread. Otherwise, if that’s the information you were looking for, please let me know (or you can mark this reply post as the solution for this topic).
Thank you so much! That’s exactly what I needed.
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Although please note that the single-visit depths in the Overview paper tend to be “ideal” depths, rather than depths accounting for the variation of weather conditions that we observe in.
I would add, we do calculate one-year depths for the simulated survey in the metrics output by MAF (here is an example for baseline_v3.2_10yrs – http://astro-lsst-01.astro.washington.edu:8080/allMetricResults?runId=21#Coadded%20M5%20Maps_Yr%201)
although, DR1 is released after only 6 months of data, not one year so it’s not quite what you’re looking for either. But maybe you could scale from those numbers instead? (we do also have number of visit maps for one year as well … example again for baseline_v3.2 here - http://astro-lsst-01.astro.washington.edu:8080/allMetricResults?runId=21#Nvisits%20Maps_Yr%201).
I would add that in crowded regions of the Plane, Bulge, and Magellanic Clouds, the MAF metrics mentioned by @ljones is not enouth, because it does not consider the “crowding error” cased by the irregular background, that will cause incompleteness before the 5sigma limit is reached. In those cases a possible recipe (also using MAF) is equation 1 of Rubin Observatory LSST Stars Milky Way and Local Volume Star Clusters Roadmap - NASA/ADS