Proposal: LHAASO J1852+0050u

Title: Follow-up of unidfentified LHAASO sources in the vicinity of HE pulsars and/or SNRs: LHAASO J1852+0050u

Authors: E. Mestre, D. F. Torres, W. Zhang, D. Hadasch, G. Pirola

File:1LHAASO J1852 0050u proposal.pdf

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Comments

 Comments from conveners

Dear Enrique,

We have been reading with interest the Proposal on the LHAASO sources 1LHAASO J1852+0050u. Let us provide below some comments to the proposal itself, hoping that this will make this science case even stronger.

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- I was wondering why this proposal was not submitted also to the MAGIC+LST call. The combined sensitivity should be better, despite that MAGIC does not have a FoV as large as LST. Is this because you and/or other participants in the proposal are not in MAGIC?

- It is not clear to me why LHAASO reports almost incompatible centroids for the same source when observed with WCDA and KM2A. These centroids seem to be separated by 0.85deg, which is larger than the r_39% containment radius of about 0.64 deg. By the way, is this r_39% value the same for the two sources?

- We quote in the proposal in Section 2 that the source size is suggested bo be ~1deg. I think the LST TAC will be a bit critical on this estimate. The r_39% containment radius can be converted to the more typical r_68% by scaling by a factor of ~1.5. This would make r_68% ~0.96 deg. The source diameter would then be about 1.92 deg, which is the actual source extension to be considered, I think. If these estimates are correct, I would suggest to update the expected source extension in these lines. I am aware that this is at the limit (if not beyond) of LST, but I think this is a more accurate estimate and needs to be reflected in the proposal.

- The estimated amount of time for a 5-sigma detection extending the fluxes reported by LHAASO should be lower than 20h. However, we ask for 20+20 hours, for two pointing positions covering the centroids of WCDA and KM2A. Do you think it would make sense to use more pointing positions to cover the whole region not only taking the LHAASO best fit positions, which actually may have a moderate to large uncertainty?

- Also related to the pointing strategy, you require "standard wobble" in the proposal. Given the large extension expected, probably it would be good idea to make the wobble offset larger, so that proper bkg regions can be found for the analysis. In this regard, let me quote below some discussions that have been taking place regarding the wobble position strategy for other LHAASO sources that we may want to follow up. In summary, it seems that we can go save in taking a wobble offset of 0.75deg, and even slightly larger values, which I think would help a lot in the case of this proposal.

- there is a "detentions" in Section 3 => "detections"