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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"

3870 results found.

  1. GRB 241029A: Mephisto observations
  2. GRB 241029A: TRT optical afterglow candidate detection
  3. GRB 241029A: SVOM/GRM observation
  4. Fermi trigger No 751861204: Global MASTER-Net observations report
  5. GRB 241029A: Fermi GBM Final Real-time Localization
  6. Fermi GRB 241026A: Global MASTER-Net observations report
  7. EP241021a: optical follow-up observations with Xinglong Observatory
  8. Fermi trigger No 751554401: Global MASTER-Net observations report
  9. EP241025a (GRB 241025A): EP observations update
  10. GRB 241018A: Mondy optical upper limit
  11. Fermi trigger No 750788395: Global MASTER-Net observations report
  12. GRB 241013B: Fermi GBM Observation
  13. GRB 241013A: Fermi GBM Observation
  14. IceCube-241006A: Upper limits from a search for additional neutrino events in IceCube
  15. GRB 241009A : Detection of a long duration GRB by SVOM/ECLAIRs
  16. LIGO/Virgo/KAGRA S241007bw: Identification of a GW compact binary merger candidate
  17. LIGO/Virgo/KAGRA S241006k: Identification of a GW compact binary merger candidate
  18. GRB 241002C: X-ray afterglow candidate observed by SVOM/MXT
  19. GRB 240929A: SAO RAS, Mondy, and CrAO optical observations
  20. Fermi GRB 241002B: Global MASTER-Net observations report
  21. GRB 241001A: Swift-XRT observations
  22. GRB 240929A: GRBAlpha detection
  23. Fermi-LAT Gamma-ray Observations of IceCube-240929A
  24. SVOM/GRM detection of a burst from SGR Swift J1818.0-1607
  25. IceCube-240929A: Upper limits from a search for additional neutrino events in IceCube
  26. LIGO/Virgo/KAGRA S240930df: 1 counterpart neutrino candidate event from an IceCube neutrino search
  27. GRB 240929A : Leavitt Observatory optical upper limit
  28. Fermi GRB 240930B: Global MASTER-Net observations report
  29. Fermi GRB 240930A: Global MASTER-Net observations report
  30. Fermi trigger No 749339671: Global MASTER-Net observations report
  31. Fermi Gamma-ray Burst Monitor trigger 749339671/240929913 is not a GRB
  32. GRB 240929A long GRB detected by INTEGRAL
  33. GRB 240929A: BALROG localization (Fermi Trigger 749332209 / GRB 240929826)
  34. Fermi GRB 240929A: Global MASTER-Net observations report
  35. GRB 240929A: Fermi GBM Final Real-time Localization
  36. Integral GRB240929.83: Global MASTER-Net observations report
  37. IceCube-240929A - IceCube observation of a high-energy neutrino candidate track-like event
  38. Insight-HXMT ToO observations of X-ray bursts from SGR 1E 1841-045 / Kes 73
  39. EP240913a/GRB 240913C: 1.6m Mephisto observations
  40. EP240918a: SVOM/VT upper limit
  41. LIGO/Virgo/KAGRA S240920dw: Identification of a GW compact binary merger candidate
  42. GRB 240821A: radio observation with the VLA
  43. LIGO/Virgo/KAGRA S240915b: Identification of a GW compact binary merger candidate
  44. EP240913a: JinShan optical upper limits
  45. GRB 240914A : An intermediate duration GRB located on-board by SVOM/ECLAIRs.
  46. Fermi trigger No 747553301: Global MASTER-Net observations report
  47. GRB 240905B: GOTO optical upper limits
  48. GRB 240905E: Swift detection of a burst
  49. Fermi GRB 240905B: Global MASTER-Net observations report
  50. LIGO/Virgo/KAGRA S240902bq: Identification of a GW compact binary merger candidate
  51. Fermi trigger No 746923430: Global MASTER-Net observations report
  52. GRB 240828A: SAO RAS AS-500(2) optical observations
  53. GRB 240829B: GRBAlpha detection
  54. GRB 240828B: AbAO optical upper limit
  55. GRB 240828B: GRANDMA Optical Upper Limit
  56. GRB 240825A: MeerKAT detection
  57. GRB 240828B: SAO RAS optical upper limit
  58. GRB 240828A: SAO RAS optical observations
  59. Fermi trigger No 746587425: Global MASTER-Net observations report
  60. GRB 240829B: Fermi GBM Final Localization
  61. GRB 240629A: First GRB Detected by BurstCube
  62. GRB 240828A: KAIT Optical Afterglow Candidate
  63. Swift GRB240829.16: Global MASTER-Net observations report
  64. LAT GRB240828.62: Global MASTER-Net observations report
  65. Fermi trigger No 746438824: Global MASTER-Net observations report
  66. GRB 240825A: SAO RAS optical observations
  67. GRB 240824A: GIT optical upper limit
  68. SGR 1E 1841-045 / Kes 73: SVOM/GRM observation
  69. SGR 1E 1841-045 / Kes 73 (Trigger 1249878): Osservatorio Atronomico Nastro Verde optical upper limit
  70. Fermi GRB 240825A: Global MASTER-Net observations report
  71. SGR 1E 1841-045 / Kes 73 (Trigger 1249653) - Osservatorio Astronomico Nastro Verde upper limit
  72. SGR 1E 1841-045 / Kes 73: Leavitt Observatory optical upper limit
  73. SGR 1E 1841-045 / Kes 73: Montarrenti Observatory optical upper limits
  74. GECAM-B observation of a short burst from SGR 1E 1841-045 / Kes 73
  75. Fermi-GBM Observations of the reactivation of SGR 1E 1841-045 / Kes 73
  76. Fermi trigger No 745866488: Global MASTER-Net observations report
  77. Trigger 1249878: Swift detection of another burst from SGR 1E 1841-045 / Kes 73
  78. Trigger 1249653: Swift detection of SGR 1E 1841-045 / Kes 73
  79. GRB 240819A: X-ray follow-up observation with EP-FXT
  80. EP240816b: Liverpool Telescope optical follow-up observations
  81. EP EP240816b: Global MASTER-Net observations report
  82. Fermi GRB 240814C: Global MASTER-Net observations report
  83. Fermi trigger No 745306088: Global MASTER-Net observations report
  84. Fermi GRB 240814B: Global MASTER-Net observations report
  85. Fermi GRB 240810A: Global MASTER-Net observations report
  86. GRB 240809A: Swift detection of a burst with a bright optical counterpart
  87. EP EP240807a: Global MASTER-Net observations report
  88. EP EP240806a: Global MASTER-Net observations report
  89. Fermi trigger No 744761058: Global MASTER-Net observations report
  90. EP240807a/GRB 240807A: EP-FXT detection of the X-ray emission
  91. EP240806A: Liverpool Telescope optical follow-up observations
  92. Fermi trigger No 744629911: Global MASTER-Net observations report
  93. Konus-Wind detection of GRB 240802A (EP240802a)
  94. GRB 240805B: NUTTelA-TAO / BSTI Optical Limits
  95. Fermi trigger No 744544656: Global MASTER-Net observations report
  96. GRB 240802A: AstroSat CZTI detection of a long burst
  97. Fermi trigger No 744128417: Global MASTER-Net observations report
  98. Fermi trigger No 743953682: Global MASTER-Net observations report
  99. Fermi Gamma-ray Burst Monitor trigger 743953682/240729575 is not a GRB
  100. Fermi GRB 240727A: Global MASTER-Net observations report

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