GCN Alert: Messaggio GCN inviato alle 2025-06-21 07:33:57: S250621w Most probable sky…

{
    "alert_type": "PRELIMINARY",
    "time_created": "2025-06-21T05:33:56Z",
    "superevent_id": "S250621w",
    "urls": {
        "gracedb": "https://gracedb.ligo.org/superevents/S250621w/view/"
    },
    "event": {
        "significant": false,
        "time": "2025-06-21T05:27:38.781Z",
        "far": 8.69535e-6,
        "instruments": [
            "H1",
            "L1"
        ],
        "group": "CBC",
        "pipeline": "CWB",
        "search": "BBH",
        "properties": {
            "HasNS": 0,
            "HasRemnant": 0,
            "HasMassGap": 0.005275362318840579
        },
        "classification": {
            "Terrestrial": 0.996792390449868,
            "BNS": 0,
            "BBH": 0.0032076095501319957,
            "NSBH": 0
        },
        "duration": null,
        "central_frequency": null
    },
    "external_coinc": null
}