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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"

26300 results found.

  1. IceCube-260827A: No transient candidates from the Zwicky Transient Facility
  2. GRB 260831B / sb26083106: SVOM/GWAC-F60A/B confirmation of optical variation of nova V* GK Per
  3. GRB 260831B / sb26083106: SVOM/VT optical variability of V* GK Per
  4. NuSTAR Transient 260828: LCO Optical Upper Limits
  5. EP260901a: EP-WXT detection of a fast X-ray transient
  6. SVOM trigger sb26083106 is not a GRB
  7. GRB 260829A: AstroSat CZTI detection
  8. GRB 260831B: EP-FXT follow-up observation
  9. GRB 260830A: NuSTAR detection of prompt emission
  10. GRB 260831B: LCO optical upper limits
  11. EP260830a: EP-WXT detection of a fast X-ray transient
  12. GRB 260827A: SVOM/GRM observation
  13. NuSTAR 260828: a 1100s hard X-ray transient
  14. GRB 260831B: SVOM detection of a possible burst
  15. IPN triangulation of GRB 260829A
  16. GRB 260827A: Glowbug gamma-ray detection
  17. EP260727a: ATCA 10 GHz detection
  18. GRB 260829A: GECAM-B observation of a long burst
  19. GRB 260825A: SVOM/GRM observation of a long burst
  20. GRB 260825A: GECAM-B observation
  21. GRB 260829A: Fermi GBM Detection
  22. GRB 260825A: AstroSat CZTI detection
  23. GRB 260818B: Further EP-FXT observation
  24. GRB 260818B: VLT optical and nIR observations
  25. GRB 260818B: TNG NIR observations
  26. IceCube-260827A - IceCube observation of a high-energy neutrino candidate track-like event
  27. GRB 260818B: 6 GHz VLA observations
  28. GRB 260818B: SVOM/VT optical upper limit and continuous observations
  29. GRB 260818B: SVOM/COLIBRÍ (FM-GFT) optical counterpart candidate
  30. GRB 260808B: SAO RAS observations of the optical rebrightening
  31. IceCube-260825A: No transient candidates from the Zwicky Transient Facility
  32. GRB 260807A: EP-FXT follow-up observations
  33. GRB 260822A: SVOM/ECLAIRs refined analysis
  34. GRB 260809A: SVOM/ECLAIRs refined analysis
  35. GRB 260822A: SVOM/VT optical upper limits
  36. IceCube-260825A - IceCube observation of a high-energy neutrino candidate track-like event
  37. GRB 260822A: PRIME near-infrared upper limits from multiple epochs
  38. GRB 260822A: EP/FXT follow-up observations
  39. GRB 260822A: the candidate optical afterglow is an unrelated type-Ia SN
  40. GRB 260818A: further EP-FXT observations and X-ray afterglow confirmation
  41. EP260822a: EP-FXT non-detection and upper limit
  42. GRB 260822A: Retraction of GOTO optical counterpart detection GCN 45431
  43. GRB 260822A: GOTO optical counterpart detection
  44. GRB 260822A: SVOM/VT optical detection of COLIBRÍ candidate
  45. GRB 260822A: SVOM/COLIBRÍ (FM-GFT) possible optical counterpart candidate
  46. EP260822a: Einstein Probe detection of a fast X-ray transient
  47. GRB 260822A: LCO optical upper limits
  48. GRB260822B: Fermi GBM Final Localization
  49. GRB 260822A: GROWTH-India Telescope Upper Limits
  50. GRB 260822A: GOTO optical upper limit
  51. GRB 260822A: SVOM detection of a short burst
  52. GRB 260818B: VLA radio observations
  53. GRB 260818B: SVOM/C-GFT optical upper limit
  54. EP260731a: SVOM/ECLAIRs detection through offline targeted search
  55. GRB 260820A: Insight-HXMT/HE detection
  56. IceCube-260821A - IceCube observation of a high-energy neutrino candidate track-like event
  57. GRB 260818B: SVOM/GRM observation
  58. EP detected a brightening of LMXB 1ES 1735-26.9
  59. GRB 260818B: Insight-HXMT detection
  60. GRB 260818B: EP-FXT follow-up observation
  61. GRB 260818A: J-band observations with WINTER
  62. GRB 260818B: SVOM/ECLAIRs refined analysis
  63. GRB 260818A: SVOM/ECLAIRs refined analysis
  64. GRB 260818B: NOT optical upper limits
  65. GRB 260810A: SVOM/GRM observation
  66. GRB 260818B: SVOM/COLIBRÍ (FM-GFT) optical upper limit
  67. GRB260818A: EP-FXT follow-up observation
  68. GRB 260818B: LCO optical upper limits
  69. GRB 260818B: SVOM detection of a short burst
  70. SVOM trigger sb26081806 is not a GRB
  71. EP260806a: SAO RAS multicolor optical observations
  72. GRB 260818A: LCO optical upper limits
  73. EP260812a: AbAO optical upper limit
  74. GRB 260818A: SVOM/COLIBRÍ (FM-GFT) optical upper limit
  75. GRB 260810A: Insight-HXMT/HE detection
  76. GRB 260818A: SVOM possible detection of a long and faint GRB
  77. EP260806a: SVOM/ECLAIRs detection through targeted search
  78. EP260806a: NUTTELA-TAO optical observations
  79. EP260812a: AZT-22 optical upper limit
  80. EP260812b: GTC/OSIRIS+ tentative spectroscopic redshift z = 2.034
  81. EP260806a: WFST optical observations
  82. EP260812b: Optical upper limit with Kinder
  83. GRB 260805D: SVOM/GRM detection of a possible magnetar burst
  84. GRB 260808B: Liverpool Telescope further optical observations
  85. EP260812a: NOT and Liverpool Telescope upper limits:
  86. EP260812b: GOTO detection of the optical counterpart
  87. EP260812a: refined analysis of the EP-WXT and autonomous EP-FXT observation
  88. EP260812a: SVOM/C-GFT optical upper limit
  89. EP260812b: COLIBRÍ optical observations
  90. EP260812b: SVOM/VT optical observation
  91. GRB 260808A: SVOM/GRM observation
  92. EP260812b: Einstein Probe detection of an X-ray transient
  93. Fermi GBM Sub-Threshold Detection of GRB 260809A
  94. GRB 260810A: Glowbug gamma-ray detection
  95. GRB 260808B: SVOM/COLIBRÍ (FM-GFT) confirmation of the optical rebrightening
  96. GRB 260810A: AstroSat CZTI detection of a long burst
  97. EP260812a: Einstein Probe detection of an X-ray transient
  98. GRB 260809A: SAO RAS optical observations
  99. GRB 260808B: SAO RAS optical observations
  100. GRB 260808B: SVOM/VT optical re-brightening at day 3

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