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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"

4183 results found.

  1. GRB 241029A: LCO optical detection
  2. Fermi trigger No 752006065: Global MASTER-Net observations report
  3. EP241021a: Swift-UVOT detection
  4. EP241021a: Optical rebrightening observations with Mephisto
  5. GRB 241029A: GROWTH-India Telescope optical follow up
  6. GRB 241029A: SAO RAS optical observations
  7. GRB 241026A: SAO RAS optical observations
  8. EP241021a: SAO RAS observations of rebrightening
  9. GRB 241029A: Fermi GBM Observation
  10. GRB 241029A: AKO Optical Afterglow Detection
  11. GRB 241029A: GOTO optical afterglow detection
  12. GRB 241029A: MASTER early optical counterpart detection
  13. GRB 241029A: Xinglong-2.16m optical afterglow confirmation
  14. GRB 241029A: Mephisto observations
  15. GRB 241029A: TRT optical afterglow candidate detection
  16. GRB 241029A: SVOM/GRM observation
  17. Fermi trigger No 751861204: Global MASTER-Net observations report
  18. GRB 241029A: Fermi GBM Final Real-time Localization
  19. Fermi GRB 241026A: Global MASTER-Net observations report
  20. EP241021a: optical follow-up observations with Xinglong Observatory
  21. Fermi trigger No 751554401: Global MASTER-Net observations report
  22. EP241025a (GRB 241025A): EP observations update
  23. GRB 241018A: Mondy optical upper limit
  24. Fermi trigger No 750788395: Global MASTER-Net observations report
  25. GRB 241013B: Fermi GBM Observation
  26. GRB 241013A: Fermi GBM Observation
  27. IceCube-241006A: Upper limits from a search for additional neutrino events in IceCube
  28. GRB 241009A : Detection of a long duration GRB by SVOM/ECLAIRs
  29. LIGO/Virgo/KAGRA S241007bw: Identification of a GW compact binary merger candidate
  30. LIGO/Virgo/KAGRA S241006k: Identification of a GW compact binary merger candidate
  31. GRB 241002C: X-ray afterglow candidate observed by SVOM/MXT
  32. GRB 240929A: SAO RAS, Mondy, and CrAO optical observations
  33. Fermi GRB 241002B: Global MASTER-Net observations report
  34. GRB 241001A: Swift-XRT observations
  35. GRB 240929A: GRBAlpha detection
  36. Fermi-LAT Gamma-ray Observations of IceCube-240929A
  37. SVOM/GRM detection of a burst from SGR Swift J1818.0-1607
  38. IceCube-240929A: Upper limits from a search for additional neutrino events in IceCube
  39. LIGO/Virgo/KAGRA S240930df: 1 counterpart neutrino candidate event from an IceCube neutrino search
  40. GRB 240929A : Leavitt Observatory optical upper limit
  41. Fermi GRB 240930B: Global MASTER-Net observations report
  42. Fermi GRB 240930A: Global MASTER-Net observations report
  43. Fermi trigger No 749339671: Global MASTER-Net observations report
  44. Fermi Gamma-ray Burst Monitor trigger 749339671/240929913 is not a GRB
  45. GRB 240929A long GRB detected by INTEGRAL
  46. GRB 240929A: BALROG localization (Fermi Trigger 749332209 / GRB 240929826)
  47. Fermi GRB 240929A: Global MASTER-Net observations report
  48. GRB 240929A: Fermi GBM Final Real-time Localization
  49. Integral GRB240929.83: Global MASTER-Net observations report
  50. IceCube-240929A - IceCube observation of a high-energy neutrino candidate track-like event
  51. Insight-HXMT ToO observations of X-ray bursts from SGR 1E 1841-045 / Kes 73
  52. EP240913a/GRB 240913C: 1.6m Mephisto observations
  53. EP240918a: SVOM/VT upper limit
  54. LIGO/Virgo/KAGRA S240920dw: Identification of a GW compact binary merger candidate
  55. GRB 240821A: radio observation with the VLA
  56. LIGO/Virgo/KAGRA S240915b: Identification of a GW compact binary merger candidate
  57. EP240913a: JinShan optical upper limits
  58. GRB 240914A : An intermediate duration GRB located on-board by SVOM/ECLAIRs.
  59. Fermi trigger No 747553301: Global MASTER-Net observations report
  60. GRB 240905B: GOTO optical upper limits
  61. GRB 240905E: Swift detection of a burst
  62. Fermi GRB 240905B: Global MASTER-Net observations report
  63. LIGO/Virgo/KAGRA S240902bq: Identification of a GW compact binary merger candidate
  64. Fermi trigger No 746923430: Global MASTER-Net observations report
  65. GRB 240828A: SAO RAS AS-500(2) optical observations
  66. GRB 240829B: GRBAlpha detection
  67. GRB 240828B: AbAO optical upper limit
  68. GRB 240828B: GRANDMA Optical Upper Limit
  69. GRB 240825A: MeerKAT detection
  70. GRB 240828B: SAO RAS optical upper limit
  71. GRB 240828A: SAO RAS optical observations
  72. Fermi trigger No 746587425: Global MASTER-Net observations report
  73. GRB 240829B: Fermi GBM Final Localization
  74. GRB 240629A: First GRB Detected by BurstCube
  75. GRB 240828A: KAIT Optical Afterglow Candidate
  76. Swift GRB240829.16: Global MASTER-Net observations report
  77. LAT GRB240828.62: Global MASTER-Net observations report
  78. Fermi trigger No 746438824: Global MASTER-Net observations report
  79. GRB 240825A: SAO RAS optical observations
  80. GRB 240824A: GIT optical upper limit
  81. SGR 1E 1841-045 / Kes 73: SVOM/GRM observation
  82. SGR 1E 1841-045 / Kes 73 (Trigger 1249878): Osservatorio Atronomico Nastro Verde optical upper limit
  83. Fermi GRB 240825A: Global MASTER-Net observations report
  84. SGR 1E 1841-045 / Kes 73 (Trigger 1249653) - Osservatorio Astronomico Nastro Verde upper limit
  85. SGR 1E 1841-045 / Kes 73: Leavitt Observatory optical upper limit
  86. SGR 1E 1841-045 / Kes 73: Montarrenti Observatory optical upper limits
  87. GECAM-B observation of a short burst from SGR 1E 1841-045 / Kes 73
  88. Fermi-GBM Observations of the reactivation of SGR 1E 1841-045 / Kes 73
  89. Fermi trigger No 745866488: Global MASTER-Net observations report
  90. Trigger 1249878: Swift detection of another burst from SGR 1E 1841-045 / Kes 73
  91. Trigger 1249653: Swift detection of SGR 1E 1841-045 / Kes 73
  92. GRB 240819A: X-ray follow-up observation with EP-FXT
  93. EP240816b: Liverpool Telescope optical follow-up observations
  94. EP EP240816b: Global MASTER-Net observations report
  95. Fermi GRB 240814C: Global MASTER-Net observations report
  96. Fermi trigger No 745306088: Global MASTER-Net observations report
  97. Fermi GRB 240814B: Global MASTER-Net observations report
  98. Fermi GRB 240810A: Global MASTER-Net observations report
  99. GRB 240809A: Swift detection of a burst with a bright optical counterpart
  100. EP EP240807a: Global MASTER-Net observations report

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