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GCN Circulars

GCN Circulars are rapid bulletins submitted by and distributed to the community. 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"

3786 results found.

  1. GRB 261029A: SVOM/ECLAIRs refined analysis
  2. GRB 261026A: Mondy, SAO RAS and Terskol optical observations
  3. GRB 261028B / MAXI J1609-487: MAXI GSC detection
  4. GRB 261029A: GOTO optical counterpart candidate
  5. GRB 261028A: Fermi GBM Final Localization
  6. GRB 261024D: AstroSat CZTI detection of a long burst
  7. Fermi GRB 261026B: Global MASTER-Net observations report
  8. EP261015b: Refined analysis of EP-FXT observations
  9. EP261006a : MeerKAT radio observations.
  10. GRB 261010A: a short minimum variability timescale and a distinct pulse evolution compatible with a merger origin
  11. GRB 261010A: 10.4m GTC spectroscopy of the galaxy 2" from the afterglow
  12. MAXI GRB261012.23: Global MASTER-Net observations report
  13. GRB 261011A: Optical followup from Sichuan South Observatory
  14. GRB 261011A: J-band observations by the SYSU 80cm infrared telescope
  15. EP261006a / AT 2026aetp: VLT/X-shooter spectroscopic redshift z = 0.1853
  16. GRB 261007A: SVOM/GRM observation
  17. The EP-WXT trigger 01709321008/EP261007b：Xinglong optical upper limit
  18. EP261006a: Swift/XRT detection of the fading X-ray counterpart
  19. GRB 261007A: SVOM/C-GFT optical observations
  20. SVOM GRB261007.23: Global MASTER-Net observations report
  21. GRB 261007A: WINTER J-band observations
  22. The EP-WXT trigger 01709320908 is likely a flaring star
  23. EP Alert 261003.01: Global MASTER-Net observations report
  24. Fermi GRB 260928A: Global MASTER-Net observations report
  25. GRB 260928A: Fermi GBM Final Real-time Localization
  26. EP260924a: Global MASTER-Net observations report
  27. The EP-WXT trigger 01709320726 is likely a flaring star
  28. GRB 260924A: Second-epoch J-band upper limit from the SYSU 80 cm infrared telescope
  29. Swift Trigger 1513439 is probably not a GRB
  30. GRB 260924A: GROWTH-India Telescope optical observations
  31. GRB 260924A: Swift detection of a burst
  32. GRB 260918A: SVOM/ECLAIRs refined analysis
  33. EP260920b: LCO optical counterpart detection
  34. EP Alert 260921.01: Global MASTER-Net observations report
  35. EP Alert 260920.66: Global MASTER-Net observations report
  36. EP260917b: EP-WXT detection of an X-ray transient
  37. IPN triangulation of GRB 260810A
  38. EP Alert 260917.32: Global MASTER-Net observations report
  39. GRB 260918A: SVOM/COLIBRÍ (FM-GFT) optical upper limits
  40. GRB 260914A: 2.2m CAHA optical afterglow detection and 10.4m GTC redshift confirmation
  41. GRB 260916A: MAXI/GSC detection
  42. EP Alert 260914.53: Global MASTER-Net observations report
  43. SVOM GRB260914.47: Global MASTER-Net observations report
  44. GRB 260907A: SVOM/GRM observation
  45. GRB 260907A: Glowbug gamma-ray detection of a likely short burst
  46. Fermi GRB 260907A: Global MASTER-Net observations report
  47. GRB 260907A: Fermi GBM Final Real-time Localization
  48. EP Alert 260903.62: Global MASTER-Net observations report
  49. SVOM GRB260903A: Global MASTER-Net observations report
  50. Konus-Wind detection of GRB 260829A
  51. GRB 260829A: SVOM/GRM observation
  52. IceCube-260827A: No transient candidates from the Zwicky Transient Facility
  53. NuSTAR 260828: a 1100s hard X-ray transient
  54. EP260727a: ATCA 10 GHz detection
  55. IceCube-260827A: Upper limits from a search for additional neutrino events in IceCube
  56. GRB 260818B: TNG NIR observations
  57. MAXI GRB260827.40: Global MASTER-Net observations report
  58. EP Alert 260820.31: Global MASTER-Net observations report
  59. IceCube Alert 260825A: Global MASTER-Net observations report
  60. GRB 260822A: GOTO optical counterpart detection
  61. GRB260822B: Fermi GBM Final Localization
  62. GRB 260818B: VLA radio observations
  63. EP260806a: SAO RAS multicolor optical observations
  64. EP260812a: SVOM/C-GFT optical upper limit
  65. GRB 260808B: SVOM/VT optical afterglow confirmation
  66. GRB 260808B: SVOM/VT optical candidate from VHF data ( localization correction for GCN 45317 )
  67. GRB 260808B: SVOM/VT optical candidate from VHF data
  68. EP260806a: Einstein Probe detection of an X-ray transient
  69. SN 2026stf / GRB 260708A: ATLAS forced photometry
  70. Fermi GRB 260805A: Global MASTER-Net observations report
  71. GRB 260803A: Fermi GBM Final Real-time Localization
  72. Fermi GRB 260802B: Global MASTER-Net observations report
  73. GRB 260802A / EP J223759.5+531421: SVOM/VT optical upper limit
  74. GRB260730A: Fermi GBM Final Localization
  75. EP260727a: VLT/X-shooter spectroscopic redshift z = 2.817
  76. GRB 260727A: AbAO and SAO RAS optical observations
  77. EP260728a: EP-FXT follow-up observation
  78. EP260727a: 1.5m OSN optical counterpart detection
  79. GRB 260726A: Liverpool Telescope optical observations
  80. GRB 260727A: Liverpool Telescope optical upper limits
  81. EP260727a: Liverpool Telescope confirmation of optical counterpart
  82. GRB 260728A: Fermi GBM Final Localization
  83. GRB 260726A: SVOM/VT optical candidate
  84. EP260723a: SVOM/VT optical observation
  85. SVOM trigger sb26071506: SVOM/VT confirmation of a stellar flare
  86. Fermi GRB 260718A: Global MASTER-Net observations report
  87. GRB260708B: MAXI/GSC detection
  88. Fermi GBM Sub-Threshold Detection of GRB 260705A
  89. GRB 260705A: SVOM detection of a burst
  90. GRB 260610B / AT2026owq: SAO RAS, CrAO and INASAN further optical observations and light curve
  91. Fermi trigger No 804552016: Global MASTER-Net observations report
  92. Fermi GRB 260628A: Global MASTER-Net observations report
  93. GRB 260628A: Fermi GBM Final Real-time Localization
  94. Konus-Wind detection of GRB 260623B / EP260623a
  95. IPN triangulation of GRB 260605A
  96. GRB 260604A: 239Alferov CubeSat detection
  97. GRB 260506B: cubesat Avion detection
  98. EP260616a/GRB260616B: COLIBRÍ optical upper limit
  99. GRB 260614A: AstroSat CZTI detection
  100. The EP-WXT trigger 01709269893 is likely a flaring star

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