The coincident detection the connection between binary neutron (SGRBs) [1]. Given can exploit sample of SGRBs. bursts we of GW 170817 and GRB 170817A cemented gamma-ray waves, star (BNS) mergers and short-duration the low number of BNS mergers detected through gravitational this connection to study BNSs through the much larger distribution [4]. small [2]. [3] distribution The majority of SGRBs are found nearby a galaxy, which is usually deemed as the host if the probability of chance alignment is is very and this these binaries receive a kick to inform BNS properties, or the delay time The offset from the host sometimes large is consistent with the BNSs being the bursts’ progenitors, since at their formation. The host properties and the SGRB offset can be used such as the kick In the following, short with a machine-learning algorithm [5]. bursts recognized as short by older probability of chance alignment. To from HST, thus the the whole sample. observations we employ a sample of gamma-ray bursts classified as This sample is enhanced with other works. We pick as putative host the galaxy with the lowest date, we have analyzed only the hosts with archival results presented cover only a fraction of [1] L13 [2] 56 [3] 190 [4] 5220 [5] L20 [6] 220 [7] 770 [8] 2004 [9] 897 [10] orientations. [11] Abbott B.P., Abbott R., Abbott T.D. et al. 2017, ApJ, 848, Fong W., Berger E., Chornock R. et al. 2013, ApJ, 769, Zevin M., Kelley L.Z., Nugent A. et al. 2020, ApJ, 904, McCarthy K.S., Zheng Z., Ramirez-Ruiz E. 2020, MNRAS, 499, Jespersen C.K., Severin J.B., Steinhardt C.L. et al. 2020, ApJ, 896, Kormendy J., Freeman K.C. 2004, IAUS Thomas J., Saglia R.P., Bender R. et al. 2009, ApJ, 691, Church R.P., Levan A.J., Davies M.B. et al. 2011, MNRAS, 413, Hurley J.R., Tout C.A., Pols O.R. 2002, MNRAS, 329, Bovy J. 2015, ApJS, 216, 29 The assumption of isotropic orientations has been tested for a couple of edge-on late-type host, showing no much difference in the offset distribution w.r.t. those from arbitrary Possible explanations: - got the wrong host - missing dominant - missing part or - accretion star-black hole binaries) missing evolution populations (e.g. neutron of the halo satellite galaxies episodes during the host early-type K-S for host. The test 0.86 late-type hosts, and 0.14 for for F against a uniform distribution gives a p-value of late-type (blue) galaxy. offset Offset distributions as predicted by BNS mergers. Black dots indicate the observed SGRB s (burst ID in brackets). Colours indicate whether the host is an early- (red) or a BNSs? merging uniformly distributed. How to assess the positions of For each burst, offset. be if F should observed offsets were SGRB are consistent with the we take the fraction of merging BNSs within the SGRB If the observed offsets realizations of our synthetic distributions, then F The the the gravitational potential halo. For each host, from host luminosity [6,7]. is reproduced with a logarithmic-profile dark matter relations halo properties are derived through observational scaling The of the of a population single stellar the binary. evolving population merger with times work [8] BSE [9], with BNSs was produced for a previous compute we solar metallicity and a Kroupa IMF. From the code output and the kicks to the barycenter the of to the Binary neutron stars surface brightness and randomly oriented [10]. are randomly seeded into the potential according host galaxy. The initial orbits are assumed circular the The Each binary is merger. projected position possible SGRB offset. Galpy [11] until then kicked, and its orbit is integrated with at the merger is assumed to be a