{
  "id": "1405.5878",
  "version": "v2",
  "published": "2014-05-22T20:00:06.000Z",
  "updated": "2014-12-19T12:45:33.000Z",
  "title": "The rate, luminosity function and time delay of non-Collapsar short GRBs",
  "authors": [
    "David Wanderman",
    "Tsvi Piran"
  ],
  "comment": "12 pages, 8 figures, 5 tables. submitted to MNRAS",
  "categories": [
    "astro-ph.HE",
    "astro-ph.CO"
  ],
  "abstract": "We estimate the rate and the luminosity function of short (hard) Gamma-Ray Bursts (sGRBs) that are non-Collapsars, using the peak fluxes and redshifts of BATSE, Swift and Fermi GRBs. Following Bromberg2013 we select a sub-sample of Swift bursts which are most likely non-Collapsars. We find that these sGRBs are delayed relative to the global star formation rate (SFR) with a typical delay time of a $3-4 $~Gyr (depending on the SFR model). However, if two or three sGRB at high redshifts have been missed because of selection effects, a distribution of delay times of ~1/t would be also compatible. The current event rate of these non-Collapsar sGRBs with L_iso > 5*10^49 erg/s is 4.1(-1.9,+2.3)Gpc^-3 yr^-1. The rate was significantly larger around z ~ 1 and it declines since that time. The luminosity function we find is a broken power law with a break at 2.0(-0.4,+1.4) * 10^52~erg/s and power-law indices 0.95(-0.12,+0.12) and 2.0(-0.8,+1.0). When considering the whole Swift sGRB sample we find that it is composed of two populations: One group (~ 60%-80% of Swift sGRBs), with the above rate and time delay and a second group (~ 20%-40% of Swift sGRBs) of potential \"impostors\" that follow the SFR with no delay. These two populations are in very good agreement with the division of sGRBs to non-Collapsars and Collapsars suggested recently by Bromberg2013. If non-Collapsar sGRBs arise from neutron star merger this rate suggest a detection rate of 3-100 yr^-1 by a future gravitational wave detectors (e.g. Advanced Ligo/Virgo with detection horizon on 300 Mpc), and a co-detection with Fermi (\\swift) rate of 0.1-1 yr^-1 (0.02-0.14 yr^-1). We estimate that about 4 * 10^5 (f_b^{-1}/30) mergers took place in the Milky Way. If $0.025 m_\\odot$ were ejected in each event this would have been sufficient to produce all the heavy r-process material in the Galaxy.",
  "revisions": [
    {
      "version": "v1",
      "updated": "2014-05-22T20:00:06.000Z",
      "abstract": "We estimate the rate and the luminosity function of short (hard) Gamma-Ray Bursts (sGRBs) that are non-Collapsars, using the peak fluxes and redshifts of BATSE, Swift and Fermi GRBs. Following \\cite{Bromberg2013} we select a sub-sample of \\swift bursts which are most likely non-Collapsars. We find that these sGRBs are delayed relative to the global star formation rate (SFR) with a typical delay time of a $2.9^{+0.4}_{-0.4} $~Gyr or $3.9^{+0.4}_{-0.5}$ (depending on the SFR model). The current event rate of these non-Collapsar sGRBs with $L_{iso}>5\\times 10^{49} erg/s$ is $4.1_{-1.9}^{+2.3}Gpc^{-3}yr^{-1}$. The rate was significantly larger around $z \\sim 1$ and it declines since that time. The luminosity function we find is a broken power law with a break at $2.0_{-0.4}^{+1.4} \\times 10^{52}$~erg/s and power-law indices $0.95_{-0.1 2}^{+0.12}$ and $2.0_{-0.8}^{+1.0}$. When considering the whole \\swift sGRB sample we find that it is composed of two populations: One group ($\\approx 60\\%-80\\%$ of \\swift sGRBs) of sGRBs, with the above rate and time delay and a second group ($\\approx 20\\%-40\\%$ of \\swift sGRBs) of potential \"impostors\" that follow the SFR with no delay. These two populations are in very good agreement with the division of sGRBs to non-Collapsars and Collapsars suggested recently by \\cite{Bromberg2013}. If non-Collapsar sGRBs arise from neutron star merger this rate suggest a detection rate of 3-100 yr$^{-1}$ by a future gravitational wave detectors (e.g. Advanced Ligo/Virgo with detection horizon on 300 Mpc), and a co-detection with Fermi (\\swift) rate of 0.1-1 yr$^{-1}$ (0.02-0.14 yr$^{-1}$). We estimate that about $4 \\times 10^5 (f_b^{-1}/30)$ mergers took place in the Milky Way. If $0.025 m_\\odot$ were ejected in each event this would have been sufficient to produce all the heavy r-process material in the Galaxy.",
      "comment": "10 pages, 8 figures, 5 tables. submitted to MNRAS",
      "journal": null,
      "doi": null
    },
    {
      "version": "v2",
      "updated": "2014-12-19T12:45:33.000Z"
    }
  ],
  "analyses": {
    "keywords": [
      "luminosity function",
      "non-collapsar short grbs",
      "time delay",
      "delay time",
      "global star formation rate"
    ],
    "publication": {
      "doi": "10.1093/mnras/stv123",
      "journal": "Monthly Notices of the Royal Astronomical Society",
      "year": 2015,
      "month": "Apr",
      "volume": 448,
      "number": 4,
      "pages": 3026
    },
    "note": {
      "typesetting": "TeX",
      "pages": 12,
      "language": "en",
      "license": "arXiv",
      "status": "editable",
      "inspire": 1297898,
      "adsabs": "2015MNRAS.448.3026W"
    }
  }
}