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GCN Circulars

GCN Circulars are rapid astronomical bulletins submitted by and distributed to community members worldwide. They are used to share discoveries, observations, quantitative near-term predictions, requests for follow-up observations, or future observing plans related to high-energy, multi-messenger, and variable or transient astrophysical events. See the documentation for help with subscribing to or submitting Circulars.

Search for Circulars by submitter, subject, or body text (e.g. 'Fermi GRB').
To navigate to a specific circular, enter the associated Circular ID (e.g. 'gcn123', 'Circular 123', or '123').
Advanced Search

To narrow the search results, use advanced search syntax. This allows for specifying which circular field to search (submitter, subject, and/or body). For additional information, refer to the advanced search documentation.

Advanced Search Examples (click to copy):

subject:"Swift"
body:"GRB"
submitter:"Judith Racusin"

330 results found.

  1. Upper limits from a search for additional neutrino events in IceCube
  2. IceCube-250926A: Upper limits from a search for additional neutrino events in IceCube
  3. IceCube-250831A: Upper limits from a search for additional neutrino events in IceCube
  4. IceCube-250813A: Upper limits from a search for additional neutrino events in IceCube
  5. EP250702a/ GRB 250702B: NuSTAR X-ray Observations
  6. GRB 250706B: refined SVOM/MXT data analysis
  7. The EP-WXT trigger 01709179071 is likely a flaring star
  8. The EP-WXT trigger 01709178975 is likely a flaring star
  9. GRB 250507A: refined SVOM/MXT data analysis
  10. IceCube-250416A: Upper limits from a search for additional neutrino events in IceCube
  11. GRB 250331C: Swift/UVOT Upper Limits
  12. IceCube-250330A: Upper limits from a search for additional neutrino events in IceCube
  13. IceCube-250309A: Upper limits from a search for additional neutrino events in IceCube
  14. IceCube-250302A: Upper limits from a search for additional neutrino events in IceCube
  15. IceCube-Cascade 250215A: Upper limits from a search for additional neutrino events in IceCube
  16. LIGO/Virgo/KAGRA S250206dm: No counterpart candidates in INTEGRAL SPI-ACS prompt observation
  17. GECAM-A detection of a bright burst from SGR 1E1841-045
  18. Konus-Wind detection of a bright burst from SGR 1E1841-045 on 2025 January 23
  19. IPN triangulation of a bright burst from SGR 1E1841-045
  20. IceCube-250102A: Upper limits from a search for additional neutrino events in IceCube
  21. Fermi Gamma-ray Burst Monitor trigger 755277791/241207641 is not a GRB
  22. GRB 241130A: EIRSAT-1 GMOD Detection
  23. IceCube-241127A: Upper limits from a search for additional neutrino events in IceCube
  24. LIGO/Virgo/KAGRA S241125n: No counterpart candidates in INTEGRAL SPI-ACS prompt observation, comparisong with Swift/BAT counterpart
  25. EP241113a: Swift XRT weak detection
  26. IceCube-241113A: Upper limits from a search for additional neutrino events in IceCube
  27. SVOM/GRM detection of a short burst from SGR 1E1841-045
  28. INTEGRAL detection of a burst from 1E 1841-045
  29. EP241107a: EP on-board trigger and autonomous follow-up observation
  30. EP241025a (GRB 241025A): EP observations update
  31. GRB241017A: TOO Observations by SVOM/MXT
  32. IceCube-241006A: Upper limits from a search for additional neutrino events in IceCube
  33. Insight-HXMT ToO observations of X-ray bursts from SGR 1E 1841-045 / Kes 73
  34. SGR 1E 1841-045 / Kes 73: SVOM/GRM observation
  35. SGR 1E 1841-045 / Kes 73 (Trigger 1249878): Osservatorio Atronomico Nastro Verde optical upper limit
  36. SGR 1E 1841-045 / Kes 73 (Trigger 1249653) - Osservatorio Astronomico Nastro Verde upper limit
  37. GRB 240824A: Swift/UVOT Upper Limits
  38. SGR 1E 1841-045 / Kes 73: Leavitt Observatory optical upper limit
  39. SGR 1E 1841-045 / Kes 73: Montarrenti Observatory optical upper limits
  40. GECAM-B observation of a short burst from SGR 1E 1841-045 / Kes 73
  41. Fermi-GBM Observations of the reactivation of SGR 1E 1841-045 / Kes 73
  42. Trigger 1249878: Swift detection of another burst from SGR 1E 1841-045 / Kes 73
  43. Trigger 1249653: Swift detection of SGR 1E 1841-045 / Kes 73
  44. IceCube-Cascade 240518A: Upper limits from a search for additional neutrino events in IceCube
  45. LIGO/Virgo S240422ed: No counterpart candidates in INTEGRAL SPI-ACS prompt observation
  46. IceCube-Cascade 240416A: Upper limits from a search for additional neutrino events in IceCube
  47. IceCube-240412A: Upper limits from a search for additional neutrino events in IceCube
  48. IceCube-240327A: Upper limits from a search for additional neutrino events in IceCube
  49. IceCube-240229A: Upper limits from a search for additional neutrino events in IceCube
  50. IceCube-240204A: Upper limits from a search for additional neutrino events in IceCube
  51. IceCube-240123A: Upper limits from a search for additional neutrino events in IceCube
  52. GRB 240106A: Glowbug gamma-ray detection
  53. IceCube-240105A: Upper limits from a search for additional neutrino events in IceCube
  54. IceCube-231211A: Upper limits from a search for additional neutrino events in IceCube
  55. Fermi GRB 231108A: Global MASTER-Net observations report
  56. LIGO/Virgo/KAGRA S231014r: Identification of a GW compact binary merger candidate
  57. LIGO/Virgo S230802aq: No counterpart candidates in INTEGRAL SPI-ACS prompt observation
  58. IceCube-230727A: Upper limits from a search for additional neutrino events in IceCube
  59. IceCube-230725A: Upper limits from a search for additional neutrino events in IceCube
  60. IceCube-230708A: Upper limits from a search for additional neutrino events in IceCube
  61. IceCube-230707B: Upper limits from a search for additional neutrino events in IceCube
  62. LIGO/Virgo/KAGRA S230527c: No counterpart candidates in INTEGRAL SPI-ACS prompt observation
  63. IceCube-Cascade 230610A: Upper limits from a search for additional neutrino events in IceCube
  64. LIGO/Virgo/KAGRA S230609u: Identification of a GW compact binary merger candidate
  65. LIGO/Virgo/KAGRA S230529ay: No counterpart candidates in INTEGRAL SPI-ACS prompt observation
  66. LIGO/Virgo/KAGRA S230518h: Upper limits from Glowbug gamma-ray observations
  67. LIGO/Virgo S230518h: No counterpart candidates in INTEGRAL SPI-ACS prompt observation
  68. IceCube-Cascade 230511A: Upper limits from a search for additional neutrino events in IceCube
  69. IceCube-Cascade 230430A: Upper limits from a search for additional neutrino events in IceCube
  70. IceCube-230416A: Upper limits from a search for additional neutrino events in IceCube
  71. IceCube-230405A: Upper limits from a search for additional neutrino events in IceCube
  72. INTEGRAL detection of a burst from SGR 1806-200
  73. GRB 230307A: soft X-ray detection with LEIA
  74. GRB 230307A: GECAM detection of an extremely bright burst
  75. IceCube-230220A: Upper limits from a search for additional neutrino events in IceCube
  76. IceCube-230201A: Upper limits from a search for additional neutrino events in IceCube
  77. IceCube-230122A: Upper limits from a search for additional neutrino events in IceCube
  78. Fermi-LAT gamma-ray observations of IceCube-230112A
  79. IceCube-221229A: Upper limits from a search for additional neutrino events in IceCube
  80. Fermi-LAT gamma-ray observations of IceCube-221223A
  81. IceCube-221216A: Upper limits from a search for additional neutrino events in IceCube
  82. IceCube-221124A: Upper limits from a search for additional neutrino events in IceCube
  83. IceCube-221104A: Upper limits from a search for additional neutrino events in IceCube
  84. Konus-Wind observation of the recent SGR 1935+2154 activity
  85. INTEGRAL detection of a burst from SGR J1935+2154
  86. IceCube-220928A: Upper limits from a search for additional neutrino events in IceCube
  87. IceCube-Cascade 220826A: Upper limits from a search for additional neutrino events in IceCube
  88. IceCube-220629A: Upper limits from a search for additional neutrino events in IceCube
  89. IceCube-220627A: Upper limits from a search for additional neutrino events in IceCube
  90. IceCube-Cascade 220625A: Upper limits from a search for additional neutrino events in IceCube
  91. GRB 220518A: Swift/UVOT Detection
  92. IceCube-220509A: Upper limits from a search for additional neutrino events in IceCube
  93. IceCube-220425A: Upper limits from a search for additional neutrino events in IceCube
  94. IceCube-220424A: Upper limits from a search for additional neutrino events in IceCube
  95. IceCube-220421A: Upper limits from a search for additional neutrino events in IceCube
  96. IceCube-220317A: Upper limits from a search for additional neutrino events in IceCube
  97. IceCube-220306A: Upper limits from a search for additional neutrino events in IceCube
  98. IceCube-220303A: Upper limits from a search for additional neutrino events in IceCube
  99. GRB 220228A: Fermi-LAT detection
  100. GRB 220101A: The first example of a Petanova

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