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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"

27781 results found.

  1. EP260812a: AZT-22 optical upper limit
  2. EP260806a: WFST optical observations
  3. EP260812b: Optical upper limit with Kinder
  4. GRB 260805D: SVOM/GRM detection of a possible magnetar burst
  5. GRB 260808B: Liverpool Telescope further optical observations
  6. GRB 260813A: BALROG localization (Fermi Trigger 808341387 / GRB 260813803)
  7. EP260812a: NOT and Liverpool Telescope upper limits:
  8. EP260812b: Liverpool Telescope observations
  9. EP260812b: GOTO detection of the optical counterpart
  10. EP260812a: refined analysis of the EP-WXT and autonomous EP-FXT observation
  11. EP260812a: SVOM/C-GFT optical upper limit
  12. EP260812b: COLIBRÍ optical observations
  13. EP260812b: SVOM/VT optical observation
  14. GRB 260808A: SVOM/GRM observation
  15. EP260812b: Einstein Probe detection of an X-ray transient
  16. EP trigger #01709278129 (EP260812b?): NOT optical counterpart
  17. Fermi GBM Sub-Threshold Detection of GRB 260809A
  18. GRB 260810A: Glowbug gamma-ray detection
  19. GRB 260808B: SVOM/COLIBRÍ (FM-GFT) confirmation of the optical rebrightening
  20. GRB 260810A: AstroSat CZTI detection of a long burst
  21. EP260812a: Einstein Probe detection of an X-ray transient
  22. GRB 260809A: SAO RAS optical observations
  23. GRB 260808B: SAO RAS optical observations
  24. GRB 260317A: SVOM/ECLAIRs detection through offline targeted search and its possible association to magnetar 1E 1841-04.5
  25. EP260806a: MAO/AZT-22 optical observations
  26. IceCube-260807A: Upper limits from a search for additional neutrino events in IceCube
  27. GRB260808B: MAO/AZT-22 optical observations
  28. GRB 250607A: SVOM/ECLAIRs detection through offline targeted search
  29. GRB 260809A: J-band upper limit with WINTER
  30. GRB 260806A: Glowbug gamma-ray detection
  31. GRB260809A/EPF_J234751.2+210212: EP-FXT follow-up observation
  32. GRB 260809A: SVOM/COLIBRÍ (FM-GFT) optical observation
  33. GRB 260808B: SVOM/COLIBRÍ (FM-GFT) optical observation
  34. GRB 260809A: NOT optical observations
  35. GRB260809A: MAO/AZT-22 optical observations
  36. GRB260809A: OHP/T193 optical observations
  37. IceCube-260805A: Upper limits from a search for additional neutrino events in IceCube
  38. EP260809a: J-band upper limit with WINTER
  39. GRB 260808B: J-band upper limit with WINTER
  40. EP260809a:refined analysis of the EP-WXT and autonomous EP-FXT observation
  41. GRB 260809A: SVOM detection of a faint burst
  42. GRB 260808B: Liverpool Telescope optical observations
  43. GRB 260808B: NOT optical observations
  44. GRB 260808B: LCO optical observations
  45. GRB 260808A: NuSTAR detection of prompt emission
  46. EP260809a: COLIBRÍ optical observations
  47. EP260809a: LCO optical observation
  48. EP260809a: OHP/T193 optical observations
  49. GRB260808B: OHP/T193 optical observations
  50. GRB 260808B / EPF_J230056.0+082842: EP-FXT follow-up observation
  51. EP260809a: Einstein Probe detection of an X-ray transient
  52. GRB 260808B: SVOM/VT optical candidate from VHF data ( localization correction for GCN 45317 )
  53. GRB 260808B: SVOM/VT optical candidate from VHF data
  54. GRB 260808B: SVOM detection of a faint burst
  55. GRB 260808A: BALROG localization (Fermi Trigger 807850307 / GRB 260808119)
  56. Fermi GRB 260808A: Global MASTER-Net observations report
  57. IceCube Alert 260807A: Global MASTER-Net observations report
  58. GRB 260807A: SVOM/COLIBRÍ (FM-GFT) optical upper limit
  59. GRB 260807A: SVOM possible detection of a faint burst
  60. EP260806a: COLIBRÍ optical observations
  61. EP260806a: refined analysis of the EP-WXT and autonomous EP-FXT observations
  62. EP260806a: SVOM/VT optical observation
  63. EP260806a: Liverpool Telescope observations of the counterpart show a blue colour
  64. EP260731a: refined analysis of the EP-WXT and autonomous EP-FXT observations
  65. EP260806a: LCO likely optical counterpart
  66. EP260806a: Einstein Probe detection of an X-ray transient
  67. GRB 260715A: cubesat Avion detection
  68. GRB 260709A: cubesat Avion detection
  69. GRB 260708A: cubesat Avion detection
  70. GRB 260730B: Glowbug gamma-ray detection
  71. GRB 260805C: Glowbug gamma-ray detection
  72. GRB 260805B: Glowbug gamma-ray detection
  73. Fermi GRB 260805A: Global MASTER-Net observations report
  74. GRB 260804A: Glowbug gamma-ray detection
  75. GRB 260805B: BALROG localization (Fermi Trigger 807622617 / GRB 260805484)
  76. IceCube-Cascade 260801A: Upper limits from a search for additional neutrino events in IceCube
  77. GRB 260708A: LCO further optical observations show supernova features
  78. Fermi GRB 260802B: Global MASTER-Net observations report
  79. GRB 260802A / EP J223759.5+521421: EP-FXT follow-up observation
  80. GRB 260802A: SVOM/VT optical upper limits from VHF data
  81. GRB 260802A: LCO optical upper limits
  82. GRB 260802A / EP J223759.5+531421: SVOM/COLIBRÍ (FM-GFT) optical upper limit
  83. GRB 260802A/EP J223759.5+531421: SVOM detection of a possible magnetar burst
  84. Fermi-LAT Gamma-ray Observations of IceCube-260722A
  85. EP260731a: COLIBRÍ optical upper limit
  86. EP260731a: NOT optical upper limit
  87. GRB 260730B: NuSTAR detection of prompt emission
  88. EP260731a: Einstein Probe detection of an X-ray transient
  89. EP260728a: COLIBRÍ optical upper limit
  90. EP260729a: Einstein Probe detection of an X-ray transient
  91. EP260727a: SAO RAS optical observations
  92. GRB 260727A: AbAO and SAO RAS optical observations
  93. EP260728a: EP-FXT follow-up observation
  94. GRB 260726A: EP-FXT follow-up observations
  95. EP260728a: Einstein Probe detection of a fast X-ray transient
  96. GRB 260726A: Fermi GBM Observation
  97. EP260727a: 1.5m OSN optical counterpart detection
  98. EP260727a:refined analysis of the EP-WXT and EP-FXT observation
  99. EP260727a: OHP/T193 optical observations
  100. GRB 260726A: Liverpool Telescope optical observations

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