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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"

21634 results found.

  1. GRB 260903A: OHP/T193 optical afterglow detection
  2. NuSTAR Transient 260828: SOAR Optical Upper Limits
  3. GRB 260903A: LCO optical counterpart detection
  4. GRB 260903A: SVOM detection of a soft faint burst
  5. EP260901a: SVOM/VT optical upper limits
  6. Konus-Wind detection of GRB 260829A
  7. GRB 260829A: SVOM/GRM observation
  8. GRB 260818A: ATCA detection of a candidate radio counterpart
  9. EP260830a: EP-FXT follow-up observation
  10. GRB 260831B / sb26083106: SVOM/GWAC-F60A/B confirmation of optical variation of nova V* GK Per
  11. GRB 260831B / sb26083106: SVOM/VT optical variability of V* GK Per
  12. NuSTAR Transient 260828: LCO Optical Upper Limits
  13. EP260901a: EP-WXT detection of a fast X-ray transient
  14. GRB 260831B: LCO optical upper limits
  15. EP260830a: EP-WXT detection of a fast X-ray transient
  16. GRB 260827A: SVOM/GRM observation
  17. GRB 260831B: SVOM detection of a possible burst
  18. GRB 260825A: SVOM/GRM observation of a long burst
  19. GRB 260818B: Further EP-FXT observation
  20. GRB 260818B: VLT optical and nIR observations
  21. GRB 260818B: TNG NIR observations
  22. GRB 260818B: 6 GHz VLA observations
  23. GRB 260818B: SVOM/VT optical upper limit and continuous observations
  24. GRB 260818B: SVOM/COLIBRÍ (FM-GFT) optical counterpart candidate
  25. GRB 260808B: SAO RAS observations of the optical rebrightening
  26. GRB 260822A: SVOM/ECLAIRs refined analysis
  27. GRB 260809A: SVOM/ECLAIRs refined analysis
  28. GRB 260822A: SVOM/VT optical upper limits
  29. IceCube Alert 260825A: Global MASTER-Net observations report
  30. GRB 260822A: PRIME near-infrared upper limits from multiple epochs
  31. GRB 260822A: the candidate optical afterglow is an unrelated type-Ia SN
  32. EP260822a: EP-FXT non-detection and upper limit
  33. GRB 260822A: SVOM/COLIBRÍ (FM-GFT) possible optical counterpart candidate
  34. EP260822a: Einstein Probe detection of a fast X-ray transient
  35. GRB 260822A: LCO optical upper limits
  36. GRB 260822A: GROWTH-India Telescope Upper Limits
  37. GRB 260822A: GOTO optical upper limit
  38. GRB 260822A: SVOM detection of a short burst
  39. GRB 260818B: VLA radio observations
  40. GRB 260818B: SVOM/C-GFT optical upper limit
  41. EP260731a: SVOM/ECLAIRs detection through offline targeted search
  42. EP detected a brightening of LMXB 1ES 1735-26.9
  43. GRB260820A: Fermi GBM Final Real-Time Localization
  44. GRB 260818A: J-band observations with WINTER
  45. GRB 260818B: SVOM/ECLAIRs refined analysis
  46. GRB 260818A: SVOM/ECLAIRs refined analysis
  47. GRB 260818B: NOT optical upper limits
  48. GRB 260810A: SVOM/GRM observation
  49. GRB 260818B: SVOM/COLIBRÍ (FM-GFT) optical upper limit
  50. GRB 260818B: LCO optical upper limits
  51. EP260806a: SAO RAS multicolor optical observations
  52. GRB 260818A: LCO optical upper limits
  53. EP260812a: AbAO optical upper limit
  54. GRB 260818A: SVOM/COLIBRÍ (FM-GFT) optical upper limit
  55. EP260806a: SVOM/ECLAIRs detection through targeted search
  56. EP260806a: NUTTELA-TAO optical observations
  57. EP260812a: AZT-22 optical upper limit
  58. EP260806a: WFST optical observations
  59. EP260812b: Optical upper limit with Kinder
  60. GRB 260805D: SVOM/GRM detection of a possible magnetar burst
  61. GRB 260808B: Liverpool Telescope further optical observations
  62. EP260812a: NOT and Liverpool Telescope upper limits:
  63. EP260812b: Liverpool Telescope observations
  64. EP260812a: refined analysis of the EP-WXT and autonomous EP-FXT observation
  65. EP260812a: SVOM/C-GFT optical upper limit
  66. EP260812b: COLIBRÍ optical observations
  67. EP260812b: SVOM/VT optical observation
  68. GRB 260808A: SVOM/GRM observation
  69. EP260812b: Einstein Probe detection of an X-ray transient
  70. EP trigger #01709278129 (EP260812b?): NOT optical counterpart
  71. GRB 260808B: SVOM/COLIBRÍ (FM-GFT) confirmation of the optical rebrightening
  72. GRB 260810A: AstroSat CZTI detection of a long burst
  73. EP260812a: Einstein Probe detection of an X-ray transient
  74. GRB 260809A: SAO RAS optical observations
  75. GRB 260808B: SAO RAS optical observations
  76. GRB 260317A: SVOM/ECLAIRs detection through offline targeted search and its possible association to magnetar 1E 1841-04.5
  77. EP260806a: MAO/AZT-22 optical observations
  78. GRB260808B: MAO/AZT-22 optical observations
  79. GRB 250607A: SVOM/ECLAIRs detection through offline targeted search
  80. GRB 260809A: J-band upper limit with WINTER
  81. GRB 260805C: CALET Gamma-Ray Burst Monitor detection
  82. GRB 260809A: SVOM/COLIBRÍ (FM-GFT) optical observation
  83. GRB 260808B: SVOM/COLIBRÍ (FM-GFT) optical observation
  84. GRB 260809A: NOT optical observations
  85. GRB260809A: MAO/AZT-22 optical observations
  86. GRB260809A: OHP/T193 optical observations
  87. EP260809a: J-band upper limit with WINTER
  88. GRB 260808B: J-band upper limit with WINTER
  89. GRB 260808B: SVOM/ECLAIRs refined analysis
  90. EP260809a:refined analysis of the EP-WXT and autonomous EP-FXT observation
  91. GRB 260809A: SVOM detection of a faint burst
  92. GRB 260808B: Liverpool Telescope optical observations
  93. GRB 260808B: NOT optical observations
  94. GRB 260808B: LCO optical observations
  95. EP260809a: COLIBRÍ optical observations
  96. EP260809a: LCO optical observation
  97. EP260809a: OHP/T193 optical observations
  98. GRB260808B: OHP/T193 optical observations
  99. EP260809a: Einstein Probe detection of an X-ray transient
  100. GRB 260808B: SVOM/VT optical candidate from VHF data ( localization correction for GCN 45317 )

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