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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"

37512 results found.

  1. GRB 240912A: Fermi GBM Final Real-time Localization
  2. GRB 240910A: Fermi GBM Observation
  3. GRB 240910A: NOT optical observations
  4. GRB 240911A : a likely weak GRB detected by SVOM/ECLAIRs
  5. GRB 240910A: Swift-XRT detection of GOTO24fvl/AT2024vfp
  6. GRB 240910A: JinShan optical observations
  7. GRB 240910A: GOTO candidate optical counterpart
  8. GRB 240710A: SVOM/GRM observation
  9. GRB 240910A: Swift ToO observations
  10. IPN triangulation of GRB 240905B (short)
  11. GRB 240825A: 7DT Optical Upper Limit
  12. GRB 240905E: SVOM/VT optical observations
  13. GRB 240905E: SVOM/VT optical observations (duplicate submission of GCN 37453)
  14. GRB 240910A: GRBAlpha detection
  15. GRB 240910B: Fermi GBM Final Real-time Localization
  16. GRB 240910A: SVOM/GRM observation
  17. EP240908a: Mondy and AbAO follow-up observations
  18. Fermi GRB 240910A: Global MASTER-Net observations report
  19. GRB 240910A: Fermi GBM Final Real-time Localization
  20. LIGO/Virgo/KAGRA S240908bs: Upper limits from Swift/BAT-GUANO
  21. LIGO/Virgo/KAGRA S240907cg: Upper limits from Swift/BAT-GUANO
  22. GRB 240905B: Fermi GBM Observation
  23. Fermi trigger No 747553301: Global MASTER-Net observations report
  24. GRB 240905B: GOTO optical upper limits
  25. Fermi GRB 240908A: Global MASTER-Net observations report
  26. GRB 240908A: Fermi GBM Final Real-time Localization
  27. GRB 240801A: SVOM/GRM observation
  28. GRB 240905E: GIT optical upper limit
  29. GRB 240905B: Swift-XRT observations
  30. GRB 240905E: Gaoyazi/GOT optical upper limits
  31. GRB 240905E: NUTTelA-TAO / BSTI Optical Limits
  32. GRB 240905B: Fermi-LAT detection
  33. GRB 240905B: Swift ToO observations
  34. GRB 240905E: J-band observations with WINTER
  35. GRB 240905E: CrAO Optical Afterglow observations, possible OT candidate
  36. GRB 240905E: AKO Optical Upper Limit
  37. GRB 240905E: SVOM/C-GFT optical upper limit
  38. GRB 240905E: OHP/MISTRAL T193 optical upper limit
  39. Fermi GRB 240905D: Global MASTER-Net observations report
  40. Fermi GRB 240905A: Global MASTER-Net observations report
  41. GRB 240905E: NOT optical upper limits
  42. GRB 240905E: REM optical/NIR upper limits
  43. GRB 240902B: AstroSat CZTI detection of a long burst
  44. GRB 240905E: Swift-XRT refined Analysis
  45. GRB 240902A: AstroSat CZTI detection of a long burst
  46. GRB 240905E: SVOM/GRM observation
  47. GRB 240905E: LCOGT Optical Upper Limit
  48. GRB 240905E: Swift/UVOT Upper Limits
  49. GRB 240905E: SAO RAS optical upper limit
  50. GRB 240825A: Montarrenti Observatory optical follow-up observations
  51. GRB 240905E: Nanshan/HMT optical upper limit
  52. Swift GRB 240905E: Global MASTER-Net observations report
  53. GRB 240905E: Swift detection of a burst
  54. GRB 240819A: Optical upper limits from TESS
  55. GRB 240905D: AstroSat CZTI detection
  56. GRB 240905A: SVOM/GRM observation
  57. Fermi GRB 240905B: Global MASTER-Net observations report
  58. GRB 240905D: Fermi GBM Final Real-time Localization
  59. GRB 240905B: AstroSat CZTI detection and localization
  60. GRB 240905C: Fermi GBM Final Real-time Localization
  61. GRB 240905B: Fermi GBM Final Real-time Localization
  62. GRB 240825A: ATCA Detection of Radio Counterpart
  63. Swift GRB 240904A: Global MASTER-Net observations report
  64. GRB 240905A: Fermi GBM Final Real-time Localization
  65. Fermi Gamma-ray Burst Monitor trigger 747163821/240904729 is not a GRB
  66. Fermi trigger No 747163821: Global MASTER-Net observations report
  67. GRB 240904A: Swift detection of a burst
  68. GRB 240828A: SVOM/GRM observation
  69. LIGO/Virgo/KAGRA S240825ar: Upper limits from Swift/BAT-GUANO
  70. LIGO/Virgo/KAGRA S240807h: Upper limits from Swift/BAT-GUANO
  71. Fermi Gamma-ray Burst Monitor trigger 240831A is not a GRB
  72. GRB 240828A: GECAM detection
  73. GRB 240831B: Fermi GBM Final Localization
  74. Fermi Gamma-ray Burst Monitor trigger 746882332/240901471 is not a GRB
  75. GRB 240825A: Magnitude Correction in SVOM/C-GFT Optical Observations
  76. GRB 240825A: MeerLICHT afterglow detection
  77. Fermi trigger No 746923430: Global MASTER-Net observations report
  78. GRB 240828A: SAO RAS AS-500(2) optical observations
  79. GRB 240821A: VLT spectroscopic observations
  80. Fermi trigger No 746882332: Global MASTER-Net observations report
  81. GRB 240825A: TSHAO Optical Upper Limit
  82. GRB 240829B: GRBAlpha detection
  83. GRB240828B: REM optical/NIR upper limits
  84. Fermi trigger No 746816563: Global MASTER-Net observations report
  85. GRB 240828B: AbAO optical upper limit
  86. GRB 240831A: Fermi GBM Final Real-time Localization
  87. GRB 240825A: SOAR observations
  88. GRB 240828B: Mephisto optical upper limit
  89. GRB 240828B: GRANDMA Optical Upper Limit
  90. GRB 240829A: Swift-BAT refined analysis
  91. GRB 240825A: Swift-BAT refined analysis
  92. GRB 240825A: MeerKAT detection
  93. GRB 240828B: J-band upper limit from WINTER
  94. Fermi trigger No 746684112: Global MASTER-Net observations report
  95. GRB 240828B: GMG Optical Upper Limit
  96. GRB 240828A: KAIT continued optical observations
  97. GRB 240828B: GWAC-F50A optical upper limit
  98. GRB 240828B: SVOM/C-GFT optical upper limit
  99. GRB 240828B: SAO RAS optical upper limit
  100. GRB 240828B: KAIT optical upper limit

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