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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').
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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"

32531 results found.

  1. EP251220a: FTW optical and NIR observations
  2. GRB 251221A: UAFO and Mondy optical upper limit
  3. GRB 251221A: Swift/UVOT Upper Limits
  4. GRB 251221A: Fermi GBM Observation
  5. EP251220a: EP-FXT follow-up observation
  6. GRB 251220B: SVOM/GRM observation of a short burst
  7. EP251220a: COLIBRÍ confirmation of fading and photometric redshift upper limit of z < 3.4
  8. EP 251220a: GOTO optical counterpart detection
  9. GRB 251221A: COLIBRÍ detection of the optical counterpart
  10. EP 251220a: COLIBRÍ detection of the optical counterpart
  11. EP251220a: Global MASTER-Net observations report
  12. GRB 251219A: SVOM/GRM observation of a short burst
  13. Fermi-LAT Gamma-ray Observations of IceCube-251218A
  14. IceCube-251218A: Upper limits from a search for additional neutrino events in IceCube
  15. IceCube-251218A: COLIBRÍ optical upper limits
  16. GRB 251214B: VIRT Optical Upper Limit
  17. Fermi GRB 251217A: Global MASTER-Net observations report
  18. GRB 251215A: Swift/UVOT Upper LImits
  19. GRB 251215A: Fermi GBM Observation
  20. Fermi GRB 251216A: Global MASTER-Net observations report
  21. GRB 251202A/EP251202a: Koshka optical upper limit
  22. GRB 251214B: Mondy optical upper limit
  23. GRB 251215A: COLIBRÍ optical upper limit
  24. EP251214b: KAIT optical upper limit
  25. Fermi GRB 251215A: Global MASTER-Net observations report
  26. EP251214a: Optical upper limit with Kinder observations
  27. GRB 251214B: 1.6m Mephisto observations with newly installed mosaic cameras
  28. GRB 251215A: Glowbug gamma-ray detection
  29. GRB 251214B: UAFO optical upper limit
  30. GRB 251214B: VLT/X-shooter observations
  31. GRB 251213A: GRID-10B observation
  32. GRB 251214B: Swift-BAT refined analysis
  33. GRB 251202A: radio detection with the VLA
  34. EP251214b: Global MASTER-Net observations report
  35. EP251214b : Einstein Probe detection of a fast X-ray transient
  36. EP251214b : Einstein Probe detection of a fast X-ray transient
  37. GRB 251214B: AbAO optical observations
  38. GRB 251214B: LCO detection of the optical counterpart
  39. GRB 251209A: GECAM-B observation of a long burst
  40. GRB 251214D: GECAM-B observation of a long burst
  41. GRB 251214B: Fermi GBM Observation
  42. GRB 251209A: Insight-HXMT/HE detection
  43. GRB 251215A: Swift ToO observations
  44. EP251214b (EP trigger 01709250023): LCO optical limits
  45. GRID detection of GRB 251213A
  46. GRB 251203B: AbAO optical observations
  47. GRB 251215A: Swift/BAT-GUANO arcminute localization of a burst
  48. GRB 251214B: GECAM-B observation of a long burst
  49. GRB 251213A: SVOM/GRM observation
  50. EP251214a: KAIT optical upper limit
  51. GRB 251213A: AstroSat CZTI detection
  52. GRB 251214A: AstroSat CZTI detection
  53. GRB 251214B: Swift/UVOT Detection
  54. GRB 251214B: COLIBRÍ observations of the afterglow
  55. EP251214a: EP-FXT non-detection and upper limit
  56. GRB 251214A: GECAM-B observation of a likely long burst
  57. GRB 251214B: 1.3m DFOT optical detection
  58. EP251214a: Global MASTER-Net observations report
  59. GRB 251214B: Xinglong-2.16m optical observation
  60. GRB 251214B : MASTER optical afterglow detection
  61. GRB 251214B: SVOM/C-GFT optical observations
  62. EP251214a: COLIBRÍ optical upper limit
  63. Swift GRB 251214B: Global MASTER-Net observations report
  64. EP251214a: EP-WXT detection of an X-ray transient possibly associated with GRB 251214A
  65. Fermi GRB 251214A: Global MASTER-Net observations report
  66. EP251212a: Global MASTER-Net observations report
  67. EP251212a: KAIT optical upper limit
  68. EP251212a / GRB 251212A: AstroSat CZTI detection
  69. EP251212a: EP-FXT follow-up observation
  70. GRB 251211B: AstroSat CZTI detection
  71. IceCube-251210A: No Candidate Transients from the Zwicky Transient Facility
  72. GRB 251209A: NuSTAR detection of prompt emission
  73. EP251212a : COLIBRÍ optical upper limit
  74. EP251212a: Einstein Probe detection of an X-ray transient
  75. Fermi-LAT Gamma-ray Observations of IceCube-251210A
  76. IceCube-251210A: Upper limits from a search for additional neutrino events in IceCube
  77. Fermi GRB 251211B: Global MASTER-Net observations report
  78. IceCube-251210A: DDOTI Optical Upper Limit
  79. GRB 251209A: Fermi GBM observation
  80. GRB 251205A: 1.3m DFOT optical upper limit
  81. GRB 251209A: AstroSat CZTI detection
  82. EP251124a: Mondy optical upper limit
  83. GRB 251129A/EP251129a: AbAO and Mondy optical observations
  84. EP251130a: Mondy and AbAO optical observations
  85. GRB 251208A: AstroSat CZTI detection
  86. Fermi GBM Sub-Threshold Detection of GRB 251205A
  87. GRB 251208A: Glowbug gamma-ray detection
  88. GRB 251208B: COLIBRÍ optical upper limits
  89. EP251118a / GRB 251118C: VLT/MUSE redshift confirmation
  90. GRB 251208C: GECAM-B observation of a short burst
  91. GRB 251208A: GECAM-B observation of a short burst
  92. Fermi GRB 251209A: Global MASTER-Net observations report
  93. Fermi GRB 251208C: Global MASTER-Net observations report
  94. GRB 251206A: SVOM/COLIBRÍ (FM-GFT) optical upper limit
  95. GRB 251208B: Swift-XRT afterglow detection
  96. GRB 251208D: LAST optical upper limit
  97. GRB 251208D: LCO analysis of the XRT sources
  98. GRB 251208B: Fermi GBM Observation
  99. GRB 251208B: GROWTH-India Telescope optical upper limits
  100. GRB 251205A: J-band detection with WINTER

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