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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"

19410 results found.

  1. GRB 260818B: Further EP-FXT observation
  2. GRB 260818B: VLT optical and nIR observations
  3. GRB 260818B: TNG NIR observations
  4. GRB 260818B: 6 GHz VLA observations
  5. GRB 260818B: SVOM/COLIBRÍ (FM-GFT) optical counterpart candidate
  6. GRB 260808B: SAO RAS observations of the optical rebrightening
  7. EP Alert 260820.31: Global MASTER-Net observations report
  8. GRB 260822A: SVOM/ECLAIRs refined analysis
  9. GRB 260822A: PRIME near-infrared upper limits from multiple epochs
  10. GRB 260822A: the candidate optical afterglow is an unrelated type-Ia SN
  11. EP260822a: EP-FXT non-detection and upper limit
  12. GRB 260822A: SVOM/COLIBRÍ (FM-GFT) possible optical counterpart candidate
  13. EP260822a: Einstein Probe detection of a fast X-ray transient
  14. GRB 260822A: LCO optical upper limits
  15. GRB 260822A: GROWTH-India Telescope Upper Limits
  16. GRB 260822A: SVOM detection of a short burst
  17. GRB 260818B: SVOM/C-GFT optical upper limit
  18. EP260731a: SVOM/ECLAIRs detection through offline targeted search
  19. EP detected a brightening of LMXB 1ES 1735-26.9
  20. GRB 260818A: J-band observations with WINTER
  21. GRB 260818B: SVOM/ECLAIRs refined analysis
  22. GRB 260818A: SVOM/ECLAIRs refined analysis
  23. GRB 260818B: NOT optical upper limits
  24. GRB 260810A: SVOM/GRM observation
  25. GRB 260818B: SVOM/COLIBRÍ (FM-GFT) optical upper limit
  26. GRB 260818B: LCO optical upper limits
  27. GRB 260818B: SVOM detection of a short burst
  28. EP260806a: SAO RAS multicolor optical observations
  29. GRB 260818A: LCO optical upper limits
  30. EP260812a: AbAO optical upper limit
  31. GRB 260818A: SVOM/COLIBRÍ (FM-GFT) optical upper limit
  32. GRB 260818A: SVOM possible detection of a long and faint GRB
  33. EP260806a: NUTTELA-TAO optical observations
  34. EP260812a: AZT-22 optical upper limit
  35. EP260806a: WFST optical observations
  36. EP260812b: Optical upper limit with Kinder
  37. GRB 260805D: SVOM/GRM detection of a possible magnetar burst
  38. GRB 260808B: Liverpool Telescope further optical observations
  39. EP260812a: NOT and Liverpool Telescope upper limits:
  40. EP260812b: Liverpool Telescope observations
  41. EP260812a: refined analysis of the EP-WXT and autonomous EP-FXT observation
  42. EP260812a: SVOM/C-GFT optical upper limit
  43. EP260812b: COLIBRÍ optical observations
  44. EP260812b: SVOM/VT optical observation
  45. GRB 260808A: SVOM/GRM observation
  46. EP260812b: Einstein Probe detection of an X-ray transient
  47. EP trigger #01709278129 (EP260812b?): NOT optical counterpart
  48. GRB 260808B: SVOM/COLIBRÍ (FM-GFT) confirmation of the optical rebrightening
  49. EP260812a: Einstein Probe detection of an X-ray transient
  50. GRB 260809A: SAO RAS optical observations
  51. GRB 260808B: SAO RAS optical observations
  52. GRB 260317A: SVOM/ECLAIRs detection through offline targeted search and its possible association to magnetar 1E 1841-04.5
  53. GRB 260807A: SVOM/ECLAIRs refined analysis
  54. EP260806a: MAO/AZT-22 optical observations
  55. GRB260808B: MAO/AZT-22 optical observations
  56. GRB 250607A: SVOM/ECLAIRs detection through offline targeted search
  57. GRB 260809A: J-band upper limit with WINTER
  58. GRB 260808A: CALET Gamma-Ray Burst Monitor detection
  59. GRB 260809A: SVOM/COLIBRÍ (FM-GFT) optical observation
  60. GRB 260808B: SVOM/COLIBRÍ (FM-GFT) optical observation
  61. GRB 260809A: NOT optical observations
  62. GRB260809A: MAO/AZT-22 optical observations
  63. GRB260809A: OHP/T193 optical observations
  64. EP260809a: J-band upper limit with WINTER
  65. GRB 260808B: J-band upper limit with WINTER
  66. GRB 260808B: SVOM/ECLAIRs refined analysis
  67. EP260809a:refined analysis of the EP-WXT and autonomous EP-FXT observation
  68. GRB 260809A: SVOM detection of a faint burst
  69. GRB 260808B: Liverpool Telescope optical observations
  70. GRB 260808B: NOT optical observations
  71. GRB 260808B: LCO optical observations
  72. EP260809a: COLIBRÍ optical observations
  73. EP260809a: LCO optical observation
  74. EP260809a: OHP/T193 optical observations
  75. GRB260808B: OHP/T193 optical observations
  76. EP260809a: Einstein Probe detection of an X-ray transient
  77. GRB 260808B: SVOM/VT optical afterglow confirmation
  78. GRB 260808C: Fermi GBM Final Real-time Localization
  79. GRB 260808B: SVOM/VT optical candidate from VHF data ( localization correction for GCN 45317 )
  80. GRB 260808B: SVOM/VT optical candidate from VHF data
  81. GRB 260808B: SVOM detection of a faint burst
  82. GRB 260808A: Fermi GBM Final Real-time Localization
  83. GRB 260807A: SVOM/COLIBRÍ (FM-GFT) optical upper limit
  84. GRB 260807A: SVOM possible detection of a faint burst
  85. EP260806a: COLIBRÍ optical observations
  86. EP260806a: refined analysis of the EP-WXT and autonomous EP-FXT observations
  87. EP260806a: SVOM/VT optical observation
  88. EP260806a: Liverpool Telescope observations of the counterpart show a blue colour
  89. EP260731a: refined analysis of the EP-WXT and autonomous EP-FXT observations
  90. EP260806a: LCO likely optical counterpart
  91. EP260806a: Einstein Probe detection of an X-ray transient
  92. GRB 260802A: SVOM/VT optical upper limits from VHF data
  93. GRB 260802A: LCO optical upper limits
  94. GRB 260802A / EP J223759.5+531421: SVOM/COLIBRÍ (FM-GFT) optical upper limit
  95. GRB 260802A/EP J223759.5+531421: SVOM detection of a possible magnetar burst
  96. GRB 260731A: AstroSat CZTI detection of a long burst
  97. EP260731a: COLIBRÍ optical upper limit
  98. EP260731a: NOT optical upper limit
  99. EP260731a: Einstein Probe detection of an X-ray transient
  100. EP260728a: COLIBRÍ optical upper limit

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