GRB Counterpart Binary Conversion

gcn_classic_to_json/notices/GRB_CNTRPART/__init__.py

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+import numpy as np
+
+from ... import utils
+
+
+def parse(bin):
+    bin[5:7]  # Intentionally Omitted. Datetime of original trigger
+    bin[
+        12
+    ]  # Intentionally Omitted. According to Docs: 'filter if optical or exponent of band if radio or other'
+    # However in practise these notices seem to be created only for Swift-XRT and the energy is 0.3-10 keV for all text notices.
+    bin[13]  # Intentionally Omitted. According to Docs: 'Seeing during the observation'
+
+    misc_bits = np.flip(np.unpackbits(bin[19:20].view(dtype="u1")))
+
+    spectrum = None
+    unit = None
+    if (misc_bits[5] == 1) and (misc_bits[6] == 0):
+        spectrum = "wavelength"
+        unit = "nm"
+    elif (misc_bits[5] == 0) and (misc_bits[6] == 1):
+        spectrum = "frequency"
+        unit = "Hz"
+    elif (misc_bits[5] == 1) and (misc_bits[6] == 1):
+        spectrum = "energy"
+        unit = "keV"
+
+    expo_factor = np.float_power(
+        10, np.packbits(np.flip(misc_bits[24:])).view(dtype="i1")
+    )[0]
+
+    trig_id = np.flip(np.unpackbits(bin[18:19].view(dtype="u1")))
+
+    return {
+        "ref_ID": [bin[4]],
+        "messenger": "EM",
+        "ref_type": "GRB",
+        "trigger_time": utils.datetime_to_iso8601(bin[14], bin[15]),
+        "ra": bin[7] * 1e-4,
+        "dec": bin[8] * 1e-4,
+        "ra_dec_error": bin[11] * 1e-4,
+        "systematic_included": True,
+        "spectrum": spectrum,
+        "units": unit,
+        "energy_flux": bin[9] * 1e-2 * expo_factor,
+        "energy_flux_error": bin[10] * 1e-2 * expo_factor,
+        "flux_energy_range": [0.3, 10] if spectrum == "energy" else None,
+        "duration": bin[16] * 1e-2,
+        "confidence_level": bin[17] * 1e-4,
+        "ref_instrument": utils.binary_to_string(bin[20:24]),
+        "submitter_name": utils.binary_to_string(bin[24:39]),
+        "additional_info": "We cannot confirm whether this is the GRB or serendipitous"
+        if trig_id[1]
+        else "This is definitely related to GRB",
+    }

gcn_classic_to_json/notices/GRB_CNTRPART/example.json

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+{
+  "ref_ID": [
+    21694
+  ],
+  "messenger": "EM",
+  "ref_type": "GRB",
+  "trigger_time": "2024-05-27T21:38:36.000Z",
+  "ra": 128.2194,
+  "dec": -14.349400000000001,
+  "ra_dec_error": 0.0019,
+  "systematic_included": true,
+  "spectrum": "energy",
+  "units": "keV",
+  "energy_flux": 1.5e-13,
+  "energy_flux_error": 6e-14,
+  "flux_energy_range": [
+    0.3,
+    10
+  ],
+  "duration": 2512.31,
+  "confidence_level": 0.15,
+  "ref_instrument": "Swift-XRT",
+  "submitter_name": "Phil_Evans",
+  "additional_info": "We cannot confirm whether this is the GRB or serendipitous"
+}