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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.

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subject:"Swift"
body:"GRB"
submitter:"Judith Racusin"

28271 results found.

  1. GRB 261029A: LCO optical observations (correction to GCN 46082)
  2. GRB 261029A: SVOM/COLIBRÍ (FM-GFT) optical observations
  3. GRB 261011A: LCO optical observations
  4. GRB261029A: Early infrared detection with MDM/MIRAGE
  5. GRB 261029A: KAIT optical observations
  6. GRB 261029A: TRT optical observations
  7. EP261006a / AT 2026aetp: Xinglong 2.16-m optical follow-up
  8. EP261025a: EP-FXT follow-up observations
  9. GRB 261028B / MAXI J1609-487: MAXI GSC detection
  10. GRB 261021A: Glowbug gamma-ray detection
  11. GRB261026A: Infrared detection with MDM/MIRAGE
  12. GRB 261026A: SAO RAS optical observations
  13. EP Alert 261026.29: Global MASTER-Net observations report
  14. GRB 261026A: EP-FXT follow-up observation
  15. GRB 261024A: SVOM/GRM observation
  16. GRB 261026A: Upper Limit with 60cm Panzhihua Telescope
  17. EP 261025a: J-band upper limit with MIRAGE
  18. GRB 261024D: Glowbug gamma-ray detection
  19. GRB 261026B: NuSTAR detection of prompt emission
  20. GRB 261024D: NuSTAR detection of prompt emission
  21. GRB 261024C: NuSTAR detection of prompt emission
  22. GRB 261026A: Ondrejov D50 optical limit
  23. GRB 261026A: ULL-ASTRO-MASTER optical detection with LCO 40-cm telescope at Haleakalā Observatory
  24. GRB 261026A: J-band observations by the SYSU 80cm infrared telescope
  25. SVOM GRB261026.26: Global MASTER-Net observations report
  26. GRB 261026A: WINTER J-band observations
  27. GRB 261019A: SVOM/GRM observation
  28. Fermi GRB 261026B: Global MASTER-Net observations report
  29. GRB 261026A: SVOM/VT optical observation from VHF data
  30. GRB 261026A: KAIT optical observations
  31. GRB 261026A: SVOM/COLIBRÍ (FM-GFT) optical observations
  32. GRB 261024A: NuSTAR detection of prompt emission
  33. GRB 261026A: SVOM detection of a burst
  34. EP261025a: J-band upper limit with WINTER
  35. EP261023a: J-band upper limit with WINTER
  36. EP 261025a: COLIBRÍ optical upper limit
  37. EP261025a: Einstein Probe detection of a fast X-ray transient
  38. EP261023a: J band upper limit by SYSU 80cm infrared telescope
  39. EP261015a: VST optical observations
  40. GRB 261024A: BALROG localization (Fermi Trigger 814551785 / GRB 261024683)
  41. EP261023a: Mondy optical upper limit
  42. EP261015a: MAO/AZT-22 optical observations
  43. EP261015a: VLA non-detection
  44. EP261023a: NOT optical counterpart candidate
  45. EP261023a: Einstein Probe detection of an X-ray transient
  46. The EP-WXT trigger 01709321472 is likely a flaring star
  47. IceCube-261020A: Upper limits from a search for additional neutrino events in IceCube
  48. NuSTAR 261020, a 830s hard X-ray transient
  49. EP261015a: GSP multiband optical follow-up observations
  50. GRB 261017A: SVOM/GRM observation
  51. EP261015a: Further optical observations with the 1.3m DFOT
  52. GRB 261020B: AstroSat CZTI detection of a short burst
  53. Fermi-LAT Gamma-ray Observations of IceCube-261020A
  54. EP261015a: AZT-20 Assy-Turgen optical observations
  55. GRB 261020A: Fermi GBM Observation
  56. GRB 261017A: SAO RAS optical upper limit
  57. GRB 260903A
  58. EP261015a: Follow-up with the 1.3m DFOT
  59. EP261015a: Terskol Zeiss-2000 optical upper limit
  60. EP261007b: Further EP-FXT follow-up observations
  61. GRB 261017A: COLIBRÍ optical upper limit
  62. GRB 261020A: MAXI GSC detection
  63. EP261015a: COLIBRÍ optical observations of a rebrightening
  64. GRB 261017A: Possible Swift/UVOT Detection
  65. GRB 261017A: Luminance-band upper limit from a 28cm telescope in Chengde
  66. GRB 261017A: R-band upper limit with the 1.3-m DFOT
  67. GRB 261017A: Swift-BAT refined analysis
  68. EP261015b: NOT Optical Observations
  69. GRB 261017A: J band upper limit by the SYSU 80cm infrared telescope
  70. EP261015c: refined analysis of the EP-FXT observation favors a stellar flare interpretation
  71. GRB 261017A : MITSuME Akeno optical upper limits
  72. GRB 261017A: Swift-XRT refined Analysis
  73. GRB 261017A: Nanshan/NEXT optical upper limit
  74. GRB 261017A: Enhanced Swift-XRT position
  75. GRB 261017A: Fermi GBM Observation
  76. GRB 261017A: Swift detection of a burst
  77. EP261015a: Tentative fading of the candidate optical counterpart from the NOT
  78. EP261015b: Refined analysis of EP-FXT observations
  79. EP261015b: J-band upper limit by the SYSU 80cm infrared telescope
  80. EP261015a: refined analysis of EP-FXT observations
  81. EP261015c: J-band upper limit with WINTER
  82. EP261015a: J-band upper limit with WINTER
  83. EP261006a / AT 2026aetp: Optical follow-up with the 1.3-m DFOT
  84. GRB 261011A: 1.3m DFOT optical upper limit
  85. GRB 261010A: Pan-STARRS z-band imaging and upper limit
  86. EP261015a: SVOM/VT optical observation
  87. GRB 261010A: VLA radio observations
  88. EP261015a: COLIBRÍ optical observations
  89. EP261015c: Einstein Probe detection of a fast X-ray transient
  90. EP261015b: Einstein Probe detection of an X-ray transient
  91. EP261015a: Einstein Probe detection of a fast X-ray transient
  92. EP261015a (WXT 11900947714): Possible optical counterpart from NOT and LCO
  93. GRB 261010A: LBT tentative near-infrared detection
  94. GRB 261011A: SAO RAS and AbAO optical observations
  95. GRB 261010A: Glowbug gamma-ray detection
  96. GRB 261008A: SVOM/GRM observation
  97. GRB 261009A: GECAM-B detection of a burst
  98. EP261006a : MeerKAT radio observations.
  99. IceCube-261012A: Upper limits from a search for additional neutrino events in IceCube
  100. GRB 261010A: a short minimum variability timescale and a distinct pulse evolution compatible with a merger origin

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