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GCN Circulars

GCN Circulars are rapid bulletins submitted by and distributed to the community. 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"

21908 results found.

  1. GRB 260809A: SVOM/ECLAIRs refined analysis
  2. GRB 260822A: SVOM/VT optical upper limits
  3. IceCube Alert 260825A: Global MASTER-Net observations report
  4. GRB 260822A: PRIME near-infrared upper limits from multiple epochs
  5. GRB 260822A: the candidate optical afterglow is an unrelated type-Ia SN
  6. EP260822a: EP-FXT non-detection and upper limit
  7. GRB 260822A: SVOM/COLIBRÍ (FM-GFT) possible optical counterpart candidate
  8. EP260822a: Einstein Probe detection of a fast X-ray transient
  9. GRB 260822A: LCO optical upper limits
  10. GRB 260822A: GROWTH-India Telescope Upper Limits
  11. GRB 260822A: GOTO optical upper limit
  12. GRB 260822A: SVOM detection of a short burst
  13. GRB 260818B: VLA radio observations
  14. GRB 260818B: SVOM/C-GFT optical upper limit
  15. EP260731a: SVOM/ECLAIRs detection through offline targeted search
  16. EP detected a brightening of LMXB 1ES 1735-26.9
  17. GRB260820A: Fermi GBM Final Real-Time Localization
  18. GRB 260818A: J-band observations with WINTER
  19. GRB 260818B: SVOM/ECLAIRs refined analysis
  20. GRB 260818A: SVOM/ECLAIRs refined analysis
  21. GRB 260818B: NOT optical upper limits
  22. GRB 260810A: SVOM/GRM observation
  23. GRB 260818B: SVOM/COLIBRÍ (FM-GFT) optical upper limit
  24. GRB 260818B: LCO optical upper limits
  25. EP260806a: SAO RAS multicolor optical observations
  26. GRB 260818A: LCO optical upper limits
  27. EP260812a: AbAO optical upper limit
  28. GRB 260818A: SVOM/COLIBRÍ (FM-GFT) optical upper limit
  29. EP260806a: SVOM/ECLAIRs detection through targeted search
  30. EP260806a: NUTTELA-TAO optical observations
  31. EP260812a: AZT-22 optical upper limit
  32. EP260806a: WFST optical observations
  33. EP260812b: Optical upper limit with Kinder
  34. GRB 260805D: SVOM/GRM detection of a possible magnetar burst
  35. GRB 260808B: Liverpool Telescope further optical observations
  36. EP260812a: NOT and Liverpool Telescope upper limits:
  37. EP260812b: Liverpool Telescope observations
  38. EP260812a: refined analysis of the EP-WXT and autonomous EP-FXT observation
  39. EP260812a: SVOM/C-GFT optical upper limit
  40. EP260812b: COLIBRÍ optical observations
  41. EP260812b: SVOM/VT optical observation
  42. GRB 260808A: SVOM/GRM observation
  43. EP260812b: Einstein Probe detection of an X-ray transient
  44. EP trigger #01709278129 (EP260812b?): NOT optical counterpart
  45. GRB 260808B: SVOM/COLIBRÍ (FM-GFT) confirmation of the optical rebrightening
  46. GRB 260810A: AstroSat CZTI detection of a long burst
  47. EP260812a: Einstein Probe detection of an X-ray transient
  48. GRB 260809A: SAO RAS optical observations
  49. GRB 260808B: SAO RAS optical observations
  50. GRB 260317A: SVOM/ECLAIRs detection through offline targeted search and its possible association to magnetar 1E 1841-04.5
  51. EP260806a: MAO/AZT-22 optical observations
  52. GRB260808B: MAO/AZT-22 optical observations
  53. GRB 250607A: SVOM/ECLAIRs detection through offline targeted search
  54. GRB 260809A: J-band upper limit with WINTER
  55. GRB 260805C: CALET Gamma-Ray Burst Monitor detection
  56. GRB 260809A: SVOM/COLIBRÍ (FM-GFT) optical observation
  57. GRB 260808B: SVOM/COLIBRÍ (FM-GFT) optical observation
  58. GRB 260809A: NOT optical observations
  59. GRB260809A: MAO/AZT-22 optical observations
  60. GRB260809A: OHP/T193 optical observations
  61. EP260809a: J-band upper limit with WINTER
  62. GRB 260808B: J-band upper limit with WINTER
  63. GRB 260808B: SVOM/ECLAIRs refined analysis
  64. EP260809a:refined analysis of the EP-WXT and autonomous EP-FXT observation
  65. GRB 260809A: SVOM detection of a faint burst
  66. GRB 260808B: Liverpool Telescope optical observations
  67. GRB 260808B: NOT optical observations
  68. GRB 260808B: LCO optical observations
  69. EP260809a: COLIBRÍ optical observations
  70. EP260809a: LCO optical observation
  71. EP260809a: OHP/T193 optical observations
  72. GRB260808B: OHP/T193 optical observations
  73. EP260809a: Einstein Probe detection of an X-ray transient
  74. GRB 260808B: SVOM/VT optical candidate from VHF data ( localization correction for GCN 45317 )
  75. GRB 260808B: SVOM/VT optical candidate from VHF data
  76. GRB 260808B: SVOM detection of a faint burst
  77. GRB 260807A: SVOM/COLIBRÍ (FM-GFT) optical upper limit
  78. EP260806a: COLIBRÍ optical observations
  79. EP260806a: refined analysis of the EP-WXT and autonomous EP-FXT observations
  80. EP260806a: SVOM/VT optical observation
  81. EP260806a: Liverpool Telescope observations of the counterpart show a blue colour
  82. EP260731a: refined analysis of the EP-WXT and autonomous EP-FXT observations
  83. EP260806a: LCO likely optical counterpart
  84. EP260806a: Einstein Probe detection of an X-ray transient
  85. GRB 260715A: cubesat Avion detection
  86. GRB 260709A: cubesat Avion detection
  87. GRB 260708A: cubesat Avion detection
  88. SN 2026stf / GRB 260708A: ATLAS forced photometry
  89. GRB 260802A: SVOM/VT optical upper limits from VHF data
  90. GRB 260802A: LCO optical upper limits
  91. GRB 260802A / EP J223759.5+531421: SVOM/COLIBRÍ (FM-GFT) optical upper limit
  92. GRB 260802A/EP J223759.5+531421: SVOM detection of a possible magnetar burst
  93. GRB 260731A: AstroSat CZTI detection of a long burst
  94. GRB 260730B: AstroSat CZTI detection
  95. EP260731a: COLIBRÍ optical upper limit
  96. EP260731a: NOT optical upper limit
  97. EP260731a: Einstein Probe detection of an X-ray transient
  98. GRB 260727A: SVOM/ECLAIRs refined analysis
  99. GRB 260726A: SVOM/ECLAIRs refined analysis
  100. EP260728a: COLIBRÍ optical upper limit

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