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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"

28177 results found.

  1. GRB 261011A: SAO RAS and AbAO optical observations
  2. GRB 261010A: Glowbug gamma-ray detection
  3. GRB 261008A: SVOM/GRM observation
  4. GRB 261009A: GECAM-B detection of a burst
  5. EP261006a : MeerKAT radio observations.
  6. IceCube-261012A: Upper limits from a search for additional neutrino events in IceCube
  7. GRB 261010A: a short minimum variability timescale and a distinct pulse evolution compatible with a merger origin
  8. Fermi-LAT Gamma-ray Observations of IceCube-261012A
  9. GRB 261010A: J-band upper limit by the SYSU 80cm infrared telescope
  10. GRB 261010A: Swift-XRT refined Analysis
  11. GRB 261011A: Swift-XRT refined Analysis
  12. GRB 261011A: Enhanced Swift-XRT position
  13. GRB 261010A: a Type I-L (merger-driven) GRB candidate
  14. GRB 261011A: Swift-BAT refined analysis
  15. GRB 261010A: 10.4m GTC spectroscopy of the galaxy 2" from the afterglow
  16. MAXI GRB261012.23: Global MASTER-Net observations report
  17. GRB 261011A: REM optical/NIR observations
  18. GRB 261011A: SOAR optical afterglow observations at ~17 hours
  19. EP261006a: 10 GHz VLA observations
  20. GRB 261011A: VLT/X-shooter redshift constraints
  21. GRB 261012A: MAXI GSC detection
  22. GRB 261010A: Swift-BAT refined analysis
  23. GRB 261011A : MITSuME Akeno optical afterglow candidate detection
  24. GRB 261011A: Optical followup from Sichuan South Observatory
  25. GRB 261011A: GMG Optical Observation
  26. GRB 261011A: Liverpool Telescope optical observations
  27. GRB 261011A: J-band observations by the SYSU 80cm infrared telescope
  28. GRB 261010A: NOT confirmation of the optical afterglow
  29. GRB 261010A: Fermi GBM Observation
  30. GRB 261011A: continued LCO optical observations
  31. EP261007b: Global MASTER-Net observations report
  32. GRB 261011A: GROWTH-India Telescope optical observations
  33. GRB 261011A: Luminance-band upper limit from a 28cm telescope in Chengde
  34. Swift GRB 261011A: Global MASTER-Net observations report
  35. GRB 261011A: Optical follow-up observations with Kinder
  36. GRB 261011A: SVOM/C-GFT optical observations
  37. EP261007b: Second EP-FXT follow-up observation and a possible X-ray counterpart to the optical transient
  38. GRB 261011A: LCO optical observations
  39. GRB 261011A: SVOM/VT optical observation from VHF data
  40. GRB 261011A: LCO optical observations
  41. GRB 261011A: TRT optical afterglow detection
  42. GRB 261011A: Swift detection of an unusual burst
  43. GRB 261011A: SVOM detection of a long bright burst
  44. GRB 261010A: Enhanced Swift-XRT position
  45. EP261010a: refined analysis of the EP-WXT and autonomous EP-FXT observations
  46. EP261006a / AT 2026aetp: Luminance-band optical follow-up with small-aperture telescopes
  47. GRB 261010A: Swift detection of a burst
  48. EP261006a: Kilonova-Catcher optical follow-up and detection
  49. EP261006a / AT 2026aetp: Multiband optical follow-up with the PKU 60cm Telescope
  50. EP261010a: SVOM/VT optical upper limits
  51. EP261006a: Liverpool Telescope optical follow-up
  52. EP261010a: NOT optical upper limits
  53. EP261010a: Global MASTER-Net observations report
  54. EP261010a Einstein Probe detection of an X-ray transient
  55. GRB261007A: Lesedi optical afterglow detection
  56. EP261006a: Xinglong 2.16m/BFOSC optical follow-up observations
  57. EP261007b: SVOM/ECLAIRs Upper Limit
  58. EP261006a: Optical follow-up observations with MATCH
  59. EP261007b: J-band upper limit by SYSU 80cm infrared telescope
  60. EP261007b: Refined analysis of the EP-WXT and autonomous EP-FXT observations
  61. GRB 261007A: SVOM/ECLAIRs refined analysis
  62. GRB 261007A / EP261007a: SVOM/GWAC-F60A/B observations
  63. GRB 261007A: Glowbug gamma-ray detection
  64. EP261007b: NOT optical observations, variable source outside the FXT region
  65. EP261007b: SVOM/C-GFT optical upper limits
  66. EP261007b: J-band upper limit with WINTER
  67. The EP-WXT trigger 01709321008/EP261007b：Xinglong optical upper limit
  68. EP261006a: Swift/XRT detection of the fading X-ray counterpart
  69. EP261007a/GRB 261007A：Xinglong optical observation
  70. GRB 261007A/EP261007a: Optical follow-up observations with Kinder
  71. EP261006a: Optical follow-up observations with Kinder
  72. EP261006a: Liverpool Telescope optical observations
  73. EP261006a: Early Optical Observations by WFST
  74. GRB 261007A / EP261007a: SVOM/VT optical observations
  75. GRB 261007A: Swift-XRT afterglow detection
  76. EP261007b: SVOM/VT optical upper limits
  77. GRB 261007A: SVOM/COLIBRÍ (FM-GFT) optical observations
  78. EP261007b: Einstein Probe detection of an X-ray transient
  79. GRB 261007A / EP261007a: NuSTAR detection of prompt emission
  80. EP Alert 261007.63: Global MASTER-Net observations report
  81. GRB 261007A / EP261007a: ULL-ASTRO-MASTER detection of the optical afterglow with LCO 40-cm telescope at McDonald Observatory
  82. GRB 261007A: Autonomous identification and follow-up of the counterpart to GRB 261007A by BTSbot with ZTF and P60/SEDM
  83. SVOM GRB261007.27: Global MASTER-Net observations report
  84. GRB 261007A: GROWTH-India Telescope optical observations
  85. GRB 261007A / EP261007a: TRT optical observations
  86. GRB 261007A: SVOM/C-GFT optical observations
  87. SVOM GRB261007.23: Global MASTER-Net observations report
  88. GRB 261005B: Swift-BAT refined analysis
  89. GRB 261007A: WINTER J-band observations
  90. EP261006a: LT and NOT discovery of an optical counterpart
  91. GRB 261007A: Fermi GBM observation
  92. EP261007a/GRB 261007A: Einstein Probe detection of an X-ray transient
  93. EP261006a: SVOM/VT optical upper limits
  94. EP261006a: Einstein Probe detection of an X-ray transient
  95. GRB 261007A: KAIT optical counterpart candidate
  96. EP trigger 01709320985: SVOM/C-GFT optical upper limits
  97. GRB 261005B: Swift-XRT refined Analysis
  98. EP trigger 01709320985: Ondrejov D50 optical upper limits
  99. GRB 261005A: Glowbug gamma-ray detection
  100. GRB 261005B: Swift/UVOT Upper Limits

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