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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.

"N/A_MC161202_R1" does not adhere to advanced search syntax. Please refer to the documentation and try again.
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"

10917 results found.

  1. GRB 260610B: Further GRANDMA Optical Observations and re-brightening detection
  2. GRB 260619A: SVOM/VT optical counterpart confirmation
  3. GRB 260618B: SVOM/VT optical candidate
  4. GRB 260618B: SVOM/VT optical candidate (duplicate Submission of 45001)
  5. GRB 260617A: CALET Gamma-Ray Burst Monitor detection
  6. GRB 260618B: Fermi-LAT detection
  7. GRB 260610B: AbAO optical observations
  8. GRB 260506B: cubesat Avion detection
  9. GRB 260616B: CALET Gamma-Ray Burst Monitor detection
  10. GRB 260610B / AT2026owq: SAO RAS optical observations of possible re-brightening
  11. GRB 260429A: cubesat Avion detection
  12. GRB260616C: MAXI/GSC detection
  13. GRB 260616A: Fermi-LAT detection
  14. GRB 260610B: Terskol optical observations
  15. GRB 260614B: SVOM/VT optical afterglow confirmation
  16. GRB 260610B / AT2026owq: GRANDMA optical observations
  17. GRB 260610B / AT2026owq: further SAO RAS optical observations
  18. GRB 260611B: CALET Gamma-Ray Burst Monitor detection
  19. GRB 260610B / AT2026owq: SVOM/VT optical observations
  20. GRB 260610B: IAC-80 Optical observations
  21. GRB 260610B / AT2026owq: SAO RAS optical observations
  22. GRB 260610B / AT2026owq: Early ATLAS observations
  23. EP260610b: SVOM/VT optical confirmation with blue color
  24. EP260610b: Gemini North optical counterpart candidate
  25. EP260610a: SVOM/VT optical upper limits
  26. IPN triangulation of GRB 260601A (short/hard)
  27. IPN triangulation of GRB 260601B / EP260601a
  28. GRB 260604C: SVOM/ECLAIRs refined analysis
  29. GRB 260604C: further SAO RAS optical observations
  30. GRB 260607A: AT2026ong (GOTO26fqf) is a type-Ia SN
  31. GRB 260604C: SVOM/C-GFT upper limit
  32. GRB 260604C: GRANDMA further observations
  33. GRB 260607A: GOTO tentative optical counterpart candidate GOTO26fqf / AT2026ong
  34. GRB 260604C: Mondy optical observations: evidence of a possible brightening
  35. GRB 260607B: Fermi-LAT detection
  36. GRB 260604C: Simeiz Zeiss-1000 optical observations of the afterglow
  37. GRB 260604C: SAO RAS optical observations
  38. GRB 260604C: GRANDMA observations
  39. GRB260603A: SVOM/ECLAIRs refined analysis
  40. GRB 260604C: SVOM detection of a long burst
  41. GRB 260515A: SVOM/VT optical detection at about 18 days post trigger
  42. GRB 260603A: NOT optical observations
  43. GRB 260603A: Simeiz Zeiss-1000 optical upper limit
  44. GRB 260601A: CALET Gamma-Ray Burst Monitor detection
  45. EP260602d: Optical Upper limits with kinder observations
  46. EP260602b: Liverpool Telescope and LCO observations
  47. EP260602a: GTC and Liverpool Telescope optical observations
  48. GRB 260601B / EP260601a: Mondy optical upper limit
  49. GRB 260603A: SVOM/VT optical observations
  50. EP260602a: SVOM/VT optical candidate
  51. GRB 260601B: CALET Gamma-Ray Burst Monitor detection
  52. EP260602a: Optical upper limits with Kinder observations
  53. GRB 260601B/EP260601a: SVOM/VT optical observations
  54. AT2026nik: EP-FXT X-ray counterpart
  55. GRB 260531A: MAXI/GSC detection
  56. IPN triangulation of GRB 260527A / EP260527a
  57. EP260527a/GRB 260527A: optical upper limit with Kinder observations
  58. GRB 260529A: GOTO tentative optical afterglow candidate
  59. EP260526a: SVOM/VT optical upper limits
  60. EP260527a / GRB 260527A: NOT optical observations
  61. GRB 260527A: CALET Gamma-Ray Burst Monitor detection
  62. EP260527a: SVOM/VT optical observation
  63. GRB 260524A: SVOM/ECLAIRs detection of a burst through on-ground search
  64. EP-WXT 01709266106: NOT optical upper limits
  65. GRB 260421B: radio detection with the VLA
  66. GRB 260509A: CrAO ZTSh optical upper limit
  67. GRB 260516D: GOTO optical counterpart detection
  68. GRB 260516D: GTC/OSIRIS+ spectroscopic redshift z = 1.801
  69. GRB 260516D: SVOM/VT optical bright candidate
  70. GRB 260515A: CrAO ZTSh BVRI optical observations
  71. EP260514a: SVOM/VT optical candidate
  72. GRB 260515A: SVOM/VT optical observations
  73. GRB 260515A: GTC/OSIRIS+ spectroscopic redshift z = 0.764
  74. GRB 260510C: CALET Gamma-Ray Burst Monitor detection
  75. GRB 260509A: SVOM/VT optical observations
  76. GRB 260511A: EP-FXT follow-up observation
  77. GRB 260511B: EP-FXT follow-up observation
  78. GRB 260511A: SVOM/VT optical observations
  79. GRB 260511B: SVOM/VT optical observations
  80. GRB 260511B: OSIRIS+/GTC redshift z=2.006
  81. GRB 260510B: SVOM/ECLAIRs refined analysis
  82. GRB 260511B : MITSuME Akeno optical afterglow candidate detection
  83. GRB 260510C: SVOM/VT optical counterpart confirmation
  84. GRB 260510B: SVOM/VT optical upper limits
  85. GRB 260510C: SVOM/VT optical upper limits
  86. GRB 260510C: MAXI/GSC detection
  87. GRB 260510C: SVOM detection of a burst
  88. GRB 260510B: SVOM detection of a burst
  89. GRB 260509A: NOT spectroscopic redshift upper limit z < 1.95
  90. EP260507a: SVOM/VT optical observations
  91. EP260507a: Kinder optical counterpart candidate
  92. EP260507a: LCO optical counterpart
  93. GRB 260504B: SVOM/ECLAIRs refined analysis
  94. GRB 260504B: SVOM/VT optical upper limits
  95. GRB 260421B: radio observation with the VLA
  96. GRB 260310A / AT2026fgk: photometric monitoring and tentative maximum of a possible SN
  97. EP260416a: Mondy and Terskol optical upper limits
  98. EP260321a/SN 2026gzf: spectroscopy at Mondy observatory
  99. GRB 260401A: cubesat Avion detection
  100. The EP-WXT trigger 01709258652: Mondy optical observations

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