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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"

44399 results found.

  1. Fermi trigger No 746019401: Global MASTER-Net observations report
  2. Fermi-GBM Observations of the reactivation of SGR 1E 1841-045 / Kes 73
  3. Fermi trigger No 745935375: Global MASTER-Net observations report
  4. GRB240821A: EIRSAT-1 GMOD Detection
  5. GRB240821B: First GRB Detected by EIRSAT-1 GMOD
  6. GRB 240821A: EP-FXT follow-up observation and afterglow candidates
  7. Fermi GRB 240821B: Global MASTER-Net observations report
  8. EP240801a: Keck/LRIS spectroscopic redshift confirmation
  9. GRB 240821A: SVOM/GRM observation
  10. GRB 240821A: SVOM/GRM observation
  11. GRB 240821A: GRANDMA/LesMakes-T60 Upper Limit
  12. GRB 240821B: Fermi GBM Final Localization
  13. Fermi trigger No 745866488: Global MASTER-Net observations report
  14. Trigger 1249878: Swift detection of another burst from SGR 1E 1841-045 / Kes 73
  15. GRB 240821A: BALROG localization (Fermi Trigger 745958167 / GRB 240821775)
  16. GRB 240821A : a likely short GRB detected by SVOM/ECLAIRs
  17. GRB 240821A: Fermi GBM Final Real-time Localization
  18. GRB 240819A: Swift-XRT observations
  19. GRB 240819A: JinShan optical upper limits on one Swift/XRT source
  20. GRB 240820B: SVOM/GRM observation
  21. EP240820a: TRT optical upper limit
  22. EP240820a: EP detection of a fast X-ray transient
  23. GRB 240819A: KAIT optical upper limit
  24. Trigger 1249653: Swift detection of SGR 1E 1841-045 / Kes 73
  25. Fermi trigger No 745873283: Global MASTER-Net observations report
  26. Fermi trigger No 745871958: Global MASTER-Net observations report
  27. GRB 240819A : an X-ray transient detected by SVOM/ECLAIRs
  28. GRB 240819A: TRT optical upper limits on the Swift/XRT and EP/FXT sources
  29. GRB 240819A: X-ray follow-up observation with EP-FXT
  30. Fermi Gamma-ray Burst Monitor trigger 745811685 / 240820080 is not a GRB
  31. GRB 240820A: Fermi GBM Final Real-time Localization
  32. GRB 240819A: Swift ToO observations
  33. GRB 240814A: SVOM/GRM observation
  34. EP240816b: Liverpool Telescope optical follow-up observations
  35. GRB 240814C: SVOM/GRM observation
  36. EP240816a: BOOTES-6/DPRT optical upper limit
  37. GRB 240815A: SVOM/GRM observation
  38. GRB 240817A: Fermi GBM Final Real-time Localization
  39. Integral GRB240816.79: Global MASTER-Net observations report
  40. IceCube-240721A: AT2023qqp and AT2024pge likely unrelated
  41. GRB GRB 240809A: Osservatorio Astronomico "Nastro Verde" optical observations: detection of an optical counterpart
  42. IBAS Alert n.10856: not a GRB
  43. GRB 240805B: Osservatorio Astronomico Nastro Verde upper limit
  44. EP240816b: KAIT optical upper limit
  45. GRB 240814B: GRBAlpha detection
  46. Fermi trigger No 745501396: Global MASTER-Net observations report
  47. EP240816a: EP detection of a fast X-ray transient and follow-up observation
  48. EP EP240816b: Global MASTER-Net observations report
  49. EP240816b: TRT optical upper limit
  50. EP240816b: EP-WXT detection and EP-FXT follow-up observation of a fast X-ray transient
  51. Fermi GRB 240814A: Global MASTER-Net observations report
  52. Fermi GRB 240814C: Global MASTER-Net observations report
  53. Fermi trigger No 745306088: Global MASTER-Net observations report
  54. GRB 240814C: Fermi GBM Final Real-time Localization
  55. Fermi GRB 240814B: Global MASTER-Net observations report
  56. GRB 240812B: SVOM/GRM observation
  57. EP240802a: Kinder optical, SWIFT-UVOT, and SWIFT-XRT upper limits 6 days after the WXT detection
  58. GRB 240814B: Fermi GBM Final Real-time Localization
  59. GRB 240814A: Fermi GBM Final Real-time Localization
  60. LIGO/Virgo/KAGRA S240813d: Updated Sky localization
  61. Fermi trigger No 745220784: Global MASTER-Net observations report
  62. Konus-Wind detection of GRB 240811A
  63. Konus-Wind detection of GRB 240810A
  64. Fermi Gamma-ray Burst Monitor trigger 745220784/240813240 is not a GRB
  65. LIGO/Virgo/KAGRA S240813d: Identification of a GW compact binary merger candidate
  66. LIGO/Virgo/KAGRA S240813c: Updated Sky localization
  67. LIGO/Virgo/KAGRA S240813c: Identification of a GW compact binary merger candidate
  68. GRB 240809A: Correction to the VLA source position in GCN 37158
  69. GRB 240810A: SVOM/GRM observation
  70. Fermi Gamma-ray Burst Monitor trigger 240812940/745194848 is not a GRB
  71. Fermi Gamma-ray Burst Monitor trigger 240812917/745192855 is not a GRB
  72. Fermi Gamma-ray Burst Monitor trigger 240812917/745192855 is not a GRB
  73. GRB 240809A: ATA radio non-detection
  74. GRB 240812D: Fermi GBM Final Real-time Localization
  75. GRB 240812C: Fermi GBM Final Real-time Localization
  76. GRB 240809A : RAPAS follow-up observations
  77. GRB 240809A: VLA detection
  78. GRB 240809A: ALMA detection
  79. IPN triangulation of GRB 240810A (short)
  80. GRB 240811A: Swift-BAT refined analysis
  81. GRB 240809A: Swift-BAT refined analysis
  82. EP240807a: PRIME H-band upper limits
  83. GRB 240812B: AstroSat CZTI detection of a long burst
  84. IceCube-240808A: Upper limits from a search for additional neutrino events in IceCube
  85. GRB 240811A: Bassano Bresciano Observatory upper limit
  86. GRB 240811A: Swift-XRT refined Analysis
  87. Fermi Gamma-ray Burst Monitor trigger 745135620/240812255 is not a GRB
  88. GRB 240811A: Swift/UVOT Upper Limits
  89. EP240801a: Assy-Turgen optical observations
  90. Fermi GRB 240810A: Global MASTER-Net observations report
  91. Fermi Gamma-ray Burst Monitor trigger 240812094/745121685 is not a GRB
  92. GRB 240812A: Fermi GBM Final Real-time Localization
  93. GRB 240811A: LCOGT Optical Upper Limit
  94. GRB 240811A: Enhanced Swift-XRT position
  95. GRB 240811A: Upper limits with Mephisto
  96. Konus-Wind detection of GRB 240809A
  97. Fermi trigger No 745057312: Global MASTER-Net observations report
  98. Swift GRB 240811A: Global MASTER-Net observations report
  99. GRB 240811A: Swift detection of a burst
  100. Fermi Gamma-ray Burst Monitor trigger 745050426/240811269 is not a GRB

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