Proposal: LHAASO J1928+1746

Title: The complex region surrounding LHAASO J1928+1746

Authors: A. Tutone, M. Cardillo, D. K. Maniadakis, A. D'Aì, E. Ambrosi

File:LST Proposal LHAASO J1928 1746u.pdf

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Comments

• Comments from conveners:

MAIN COMMENTS:

The main difficulty that the proposal may face, in my opinion, is the fact that the region is rather complex, with two LHAASO sources (1 deg apart, but one needs to consider the r_39% => r_68% and check anuy possible overlapping), two HAWC sources, one HESS and VERITAS source, and several GeV sources.

The whole region extends for about 2 degrees (looking at the white contours reported in the central panel in Fig.1). Despite that LST has a larger FoV, it would really help in convincing the LST Time Allocation Committee that the instrument is actually capable to deal with such a large extension. For that, one could for instance state the latest results obtained for other crowded regions, e.g. the Galactic Center region. Otherwise, you request "standard wobble" observations, but for these you may find difficulties in finding bkg regions not "contaminated". Perhaps specifying a larger wobble offset and defining which positions should LST-1 be pointing to (e.g. placing these positions in the central panel of Fig.1) could help in assessing the feasibility of these observations.

As for the total requested time, 50h, if one looks at Fig.2 it seems that the LST 50h sensitivity curve is much below than the expected flux, and therefore much less time should be needed in principle for a 5-sigma detection. Perhaps the flux from the HAWC, HESS and VERITAS sources could also be displayed in this Fig.2, which eventually could be at a lower level, justifying why we ask for 50h. Otherwise, if all sources are potentially to be detected in much less time than 50h, one could consider lowering the total amount of requested time to, say, 30h, which probably enhances the possibilities for the proposal to be successful.

MINOR COMMENTS:

- This proposal has not been submitted to MAGIC+LST-1. Is this because you or other par ticipants in the proposal are not MAGIC members? - In the scientific rationale, yout state that "also HESS reported a significant emission exceeding a 5 sigma level" => this seems to be referred to 1LHAASO J1929+1846u* (not to the current proposed source (1LHAASO J1928+1746u). Is this correct? Perhaps stating it explicitly would avoid any confusion. Also, please add the name of the HESS source (I understand this is HESS J1930+188 - It is stated that the extension of HAWC's 5-sigma emission covers a larger area than "these two sources". Are you referring to the two LHAASO sources (1LHAASO J1928+1746u and 1LHAASO J1929+1846u*), as well as the two HAWC detected sources? For HAWC, I understand the other source apart from 3HWC J1928+178, is 3HWC J1930+188, but this source name is not appearing in the body text (only in Fig.1). - In this regard, the caption of Fig.1 should be placed a bit closer to the corresponding figure (it appears in the next page now). Note also here that the presence of VERITAS sources is not explicitly stated in the text, perhaps would be good to reference them there. - Which is the "MeV range data" you refer to? is this Fermi-LAT? please specify (and perhaps also comment on these Fermi sources)