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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"

28082 results found.

  1. The EP-WXT trigger 01709281429 is likely a flaring star
  2. EP260812a: AZT-22 optical upper limit
  3. EP260806a: WFST optical observations
  4. EP260812b: Optical upper limit with Kinder
  5. GRB 260805D: SVOM/GRM detection of a possible magnetar burst
  6. GRB 260808B: Liverpool Telescope further optical observations
  7. GRB 260813A: BALROG localization (Fermi Trigger 808341387 / GRB 260813803)
  8. EP260812a: NOT and Liverpool Telescope upper limits:
  9. EP260812b: Liverpool Telescope observations
  10. EP260812b: GOTO detection of the optical counterpart
  11. EP260812a: refined analysis of the EP-WXT and autonomous EP-FXT observation
  12. EP260812a: SVOM/C-GFT optical upper limit
  13. EP260812b: COLIBRÍ optical observations
  14. EP260812b: SVOM/VT optical observation
  15. GRB 260808A: SVOM/GRM observation
  16. EP260812b: Einstein Probe detection of an X-ray transient
  17. EP trigger #01709278129 (EP260812b?): NOT optical counterpart
  18. Fermi GBM Sub-Threshold Detection of GRB 260809A
  19. GRB 260810A: Glowbug gamma-ray detection
  20. GRB 260808B: SVOM/COLIBRÍ (FM-GFT) confirmation of the optical rebrightening
  21. GRB 260810A: AstroSat CZTI detection of a long burst
  22. EP260812a: Einstein Probe detection of an X-ray transient
  23. GRB 260809A: SAO RAS optical observations
  24. GRB 260808B: SAO RAS optical observations
  25. GRB 260317A: SVOM/ECLAIRs detection through offline targeted search and its possible association to magnetar 1E 1841-04.5
  26. EP260806a: MAO/AZT-22 optical observations
  27. IceCube-260807A: Upper limits from a search for additional neutrino events in IceCube
  28. GRB260808B: MAO/AZT-22 optical observations
  29. GRB 250607A: SVOM/ECLAIRs detection through offline targeted search
  30. GRB 260809A: J-band upper limit with WINTER
  31. GRB 260806A: Glowbug gamma-ray detection
  32. GRB260809A/EPF_J234751.2+210212: EP-FXT follow-up observation
  33. GRB 260809A: SVOM/COLIBRÍ (FM-GFT) optical observation
  34. GRB 260808B: SVOM/COLIBRÍ (FM-GFT) optical observation
  35. GRB 260809A: NOT optical observations
  36. GRB260809A: MAO/AZT-22 optical observations
  37. GRB260809A: OHP/T193 optical observations
  38. IceCube-260805A: Upper limits from a search for additional neutrino events in IceCube
  39. EP260809a: J-band upper limit with WINTER
  40. GRB 260808B: J-band upper limit with WINTER
  41. EP260809a:refined analysis of the EP-WXT and autonomous EP-FXT observation
  42. GRB 260809A: SVOM detection of a faint burst
  43. GRB 260808B: Liverpool Telescope optical observations
  44. GRB 260808B: NOT optical observations
  45. GRB 260808B: LCO optical observations
  46. GRB 260808A: NuSTAR detection of prompt emission
  47. EP260809a: COLIBRÍ optical observations
  48. EP260809a: LCO optical observation
  49. EP260809a: OHP/T193 optical observations
  50. GRB260808B: OHP/T193 optical observations
  51. GRB 260808B / EPF_J230056.0+082842: EP-FXT follow-up observation
  52. EP260809a: Einstein Probe detection of an X-ray transient
  53. GRB 260808B: SVOM/VT optical candidate from VHF data ( localization correction for GCN 45317 )
  54. GRB 260808B: SVOM/VT optical candidate from VHF data
  55. GRB 260808B: SVOM detection of a faint burst
  56. GRB 260808A: BALROG localization (Fermi Trigger 807850307 / GRB 260808119)
  57. Fermi GRB 260808A: Global MASTER-Net observations report
  58. IceCube Alert 260807A: Global MASTER-Net observations report
  59. GRB 260807A: SVOM/COLIBRÍ (FM-GFT) optical upper limit
  60. GRB 260807A: SVOM possible detection of a faint burst
  61. EP260806a: COLIBRÍ optical observations
  62. EP260806a: refined analysis of the EP-WXT and autonomous EP-FXT observations
  63. EP260806a: SVOM/VT optical observation
  64. EP260806a: Liverpool Telescope observations of the counterpart show a blue colour
  65. EP260731a: refined analysis of the EP-WXT and autonomous EP-FXT observations
  66. EP260806a: LCO likely optical counterpart
  67. EP260806a: Einstein Probe detection of an X-ray transient
  68. GRB 260715A: cubesat Avion detection
  69. GRB 260709A: cubesat Avion detection
  70. GRB 260708A: cubesat Avion detection
  71. GRB 260730B: Glowbug gamma-ray detection
  72. GRB 260805C: Glowbug gamma-ray detection
  73. GRB 260805B: Glowbug gamma-ray detection
  74. Fermi GRB 260805A: Global MASTER-Net observations report
  75. GRB 260804A: Glowbug gamma-ray detection
  76. GRB 260805B: BALROG localization (Fermi Trigger 807622617 / GRB 260805484)
  77. IceCube-Cascade 260801A: Upper limits from a search for additional neutrino events in IceCube
  78. GRB 260708A: LCO further optical observations show supernova features
  79. Fermi GRB 260802B: Global MASTER-Net observations report
  80. GRB 260802A / EP J223759.5+521421: EP-FXT follow-up observation
  81. GRB 260802A: SVOM/VT optical upper limits from VHF data
  82. GRB 260802A: LCO optical upper limits
  83. GRB 260802A / EP J223759.5+531421: SVOM/COLIBRÍ (FM-GFT) optical upper limit
  84. GRB 260802A/EP J223759.5+531421: SVOM detection of a possible magnetar burst
  85. Fermi-LAT Gamma-ray Observations of IceCube-260722A
  86. EP260731a: COLIBRÍ optical upper limit
  87. EP260731a: NOT optical upper limit
  88. GRB 260730B: NuSTAR detection of prompt emission
  89. EP260731a: Einstein Probe detection of an X-ray transient
  90. EP260728a: COLIBRÍ optical upper limit
  91. EP260729a: Einstein Probe detection of an X-ray transient
  92. EP260727a: SAO RAS optical observations
  93. GRB 260727A: AbAO and SAO RAS optical observations
  94. EP260728a: EP-FXT follow-up observation
  95. GRB 260726A: EP-FXT follow-up observations
  96. EP260728a: Einstein Probe detection of a fast X-ray transient
  97. GRB 260726A: Fermi GBM Observation
  98. EP260727a: 1.5m OSN optical counterpart detection
  99. EP260727a:refined analysis of the EP-WXT and EP-FXT observation
  100. EP260727a: OHP/T193 optical observations

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