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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"

879 results found.

  1. IceCube-251025A: Upper limits from a search for additional neutrino events in IceCube
  2. Upper limits from a search for additional neutrino events in IceCube
  3. IceCube-250926A: Upper limits from a search for additional neutrino events in IceCube
  4. IceCube-250831A: Upper limits from a search for additional neutrino events in IceCube
  5. GRB 250815A: Fermi GBM Final Localization
  6. IceCube-250813A: Upper limits from a search for additional neutrino events in IceCube
  7. The EP-WXT trigger 01709198251 is likely a flaring star
  8. Swift detection of the Soft Gamma Repeater PSR J1647-4552
  9. EP250702a/ GRB 250702B: NuSTAR X-ray Observations
  10. GRB 250706B: refined SVOM/MXT data analysis
  11. Fermi Gamma-ray Burst Monitor trigger 772838080/250628885 is not a GRB
  12. GRB 250621B: SVOM/GRM detection of a possible magnetar X-ray burst
  13. The EP-WXT trigger 01709179071 is likely a flaring star
  14. The EP-WXT trigger 01709178975 is likely a flaring star
  15. GRB 250507A: refined SVOM/MXT data analysis
  16. IceCube-250416A: Upper limits from a search for additional neutrino events in IceCube
  17. GRB 250331C: Swift/UVOT Upper Limits
  18. IceCube-250330A: Upper limits from a search for additional neutrino events in IceCube
  19. IceCube-250309A: Upper limits from a search for additional neutrino events in IceCube
  20. IceCube-250302A: Upper limits from a search for additional neutrino events in IceCube
  21. IceCube-Cascade 250215A: Upper limits from a search for additional neutrino events in IceCube
  22. LIGO/Virgo/KAGRA S250206dm: No counterpart candidates in INTEGRAL SPI-ACS prompt observation
  23. GECAM-A detection of a bright burst from SGR 1E1841-045
  24. Konus-Wind detection of a bright burst from SGR 1E1841-045 on 2025 January 23
  25. IPN triangulation of a bright burst from SGR 1E1841-045
  26. GRB 250116A: GECAM-B detection of a long burst
  27. IceCube-250102A: Upper limits from a search for additional neutrino events in IceCube
  28. Fermi Gamma-ray Burst Monitor trigger 755277791/241207641 is not a GRB
  29. GRB 241130A: EIRSAT-1 GMOD Detection
  30. IceCube-241127A: Upper limits from a search for additional neutrino events in IceCube
  31. SVOM/GRM observation of GRB 241126B or a short burst from magnetar
  32. SVOM/GRM detection of a short burst from SGR 1830
  33. GECAM detection of a short burst from SGR 1830
  34. LIGO/Virgo/KAGRA S241125n: No counterpart candidates in INTEGRAL SPI-ACS prompt observation, comparisong with Swift/BAT counterpart
  35. EP241113a: Swift XRT weak detection
  36. IceCube-241113A: Upper limits from a search for additional neutrino events in IceCube
  37. SVOM/GRM detection of a short burst from SGR 1E1841-045
  38. INTEGRAL detection of a burst from 1E 1841-045
  39. EP241107a: EP on-board trigger and autonomous follow-up observation
  40. EP241025a (GRB 241025A): EP observations update
  41. GRB241017A: TOO Observations by SVOM/MXT
  42. IceCube-241006A: Upper limits from a search for additional neutrino events in IceCube
  43. SVOM/GRM detection of a burst from SGR Swift J1818.0-1607
  44. Insight-HXMT ToO observations of X-ray bursts from SGR 1E 1841-045 / Kes 73
  45. GRB 240914A : An intermediate duration GRB located on-board by SVOM/ECLAIRs.
  46. SGR 1E 1841-045 / Kes 73: SVOM/GRM observation
  47. SGR 1E 1841-045 / Kes 73 (Trigger 1249878): Osservatorio Atronomico Nastro Verde optical upper limit
  48. SGR 1E 1841-045 / Kes 73 (Trigger 1249653) - Osservatorio Astronomico Nastro Verde upper limit
  49. GRB 240824A: Swift/UVOT Upper Limits
  50. SGR 1E 1841-045 / Kes 73: Leavitt Observatory optical upper limit
  51. SGR 1E 1841-045 / Kes 73: Montarrenti Observatory optical upper limits
  52. GECAM-B observation of a short burst from SGR 1E 1841-045 / Kes 73
  53. Fermi-GBM Observations of the reactivation of SGR 1E 1841-045 / Kes 73
  54. Trigger 1249878: Swift detection of another burst from SGR 1E 1841-045 / Kes 73
  55. Trigger 1249653: Swift detection of SGR 1E 1841-045 / Kes 73
  56. IceCube-Cascade 240518A: Upper limits from a search for additional neutrino events in IceCube
  57. LIGO/Virgo S240422ed: No counterpart candidates in INTEGRAL SPI-ACS prompt observation
  58. IceCube-Cascade 240416A: Upper limits from a search for additional neutrino events in IceCube
  59. IceCube-240412A: Upper limits from a search for additional neutrino events in IceCube
  60. IceCube-240327A: Upper limits from a search for additional neutrino events in IceCube
  61. IceCube-240229A: Upper limits from a search for additional neutrino events in IceCube
  62. IceCube-240204A: Upper limits from a search for additional neutrino events in IceCube
  63. IceCube-240123A: Upper limits from a search for additional neutrino events in IceCube
  64. IPN triangulation of GRB 240112A (long)
  65. GRB 240112A: GECAM detection of a burst
  66. GRB 240106A: Glowbug gamma-ray detection
  67. IceCube-240105A: Upper limits from a search for additional neutrino events in IceCube
  68. IceCube-231211A: Upper limits from a search for additional neutrino events in IceCube
  69. GRB 231115A: GBM/Fermi Observations of a probable Giant Flare of Magnetar
  70. GECAM-B observation of a short burst from SGR J1555-5402
  71. SGRJ1555-5402: Swift/BAT-GUANO arcminute localization of a SGR flare
  72. Fermi GRB 231108A: Global MASTER-Net observations report
  73. LIGO/Virgo/KAGRA S231014r: Identification of a GW compact binary merger candidate
  74. LIGO/Virgo S230802aq: No counterpart candidates in INTEGRAL SPI-ACS prompt observation
  75. IceCube-230727A: Upper limits from a search for additional neutrino events in IceCube
  76. IceCube-230725A: Upper limits from a search for additional neutrino events in IceCube
  77. IceCube-230708A: Upper limits from a search for additional neutrino events in IceCube
  78. IceCube-230707B: Upper limits from a search for additional neutrino events in IceCube
  79. LIGO/Virgo/KAGRA S230527c: No counterpart candidates in INTEGRAL SPI-ACS prompt observation
  80. IceCube-Cascade 230610A: Upper limits from a search for additional neutrino events in IceCube
  81. LIGO/Virgo/KAGRA S230609u: Identification of a GW compact binary merger candidate
  82. LIGO/Virgo/KAGRA S230529ay: No counterpart candidates in INTEGRAL SPI-ACS prompt observation
  83. LIGO/Virgo/KAGRA S230518h: Upper limits from Glowbug gamma-ray observations
  84. LIGO/Virgo S230518h: No counterpart candidates in INTEGRAL SPI-ACS prompt observation
  85. IceCube-Cascade 230511A: Upper limits from a search for additional neutrino events in IceCube
  86. IceCube-Cascade 230430A: Upper limits from a search for additional neutrino events in IceCube
  87. IceCube-230416A: Upper limits from a search for additional neutrino events in IceCube
  88. IceCube-230405A: Upper limits from a search for additional neutrino events in IceCube
  89. SGR 1806-20: Correction to GCN 33494
  90. INTEGRAL detection of a burst from SGR 1806-200
  91. VZLUSAT-2 detection of SGR 1806-20
  92. GRB 230307A: soft X-ray detection with LEIA
  93. Trigger 1159327: Swift detection of SGR1806-20
  94. GRB 230307A: GECAM detection of an extremely bright burst
  95. IceCube-230220A: Upper limits from a search for additional neutrino events in IceCube
  96. IceCube-230201A: Upper limits from a search for additional neutrino events in IceCube
  97. IceCube-230122A: Upper limits from a search for additional neutrino events in IceCube
  98. Fermi-LAT gamma-ray observations of IceCube-230112A
  99. IceCube-221229A: Upper limits from a search for additional neutrino events in IceCube
  100. Fermi-LAT gamma-ray observations of IceCube-221223A

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