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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"

23700 results found.

  1. GRB 260101A: Swift-BAT refined analysis
  2. Swift GRB 251230A: Global MASTER-Net OT detection
  3. EP260105b/EP-WXT trigger 01709251028: Einstein Probe detection of an X-ray transient
  4. The EP-WXT trigger 01709251028 is likely a flaring star
  5. FRB 20251229A: COLIBRÍ optical upper limits
  6. GRB 260101A: COLIBRÍ optical upper limits
  7. GRB 260104A: COLIBRÍ optical upper limits
  8. GRB 251230A/EP-WXT trigger 01709250693: Mephisto optical upper limits
  9. GRB 260104A: Swift-XRT refined Analysis
  10. GRB 260104A: Enhanced Swift-XRT position
  11. GRB 260104A: Swift detection of a burst
  12. GRB 260101A: COLIBRÍ optical observations
  13. GRB 260102A: Swift-XRT observations
  14. GRB 260102A: SVOM/COLIBRÍ (FM-GFT) optical observations
  15. EP260101a: refined analysis of the EP-WXT and EP-FXT observations
  16. EP260101a: Einstein Probe detection of an X-ray transient
  17. GRB 260101A: OSIRIS+ redshift z = 2.623 for the new year burst
  18. GRB 260101A: LCO detection of the optical counterpart
  19. GRB 260101A: Swift detection of a burst with an optical counterpart
  20. GRB 251230A: GRANDMA/TAROT Early Detection
  21. GRB 251230A/EP251230a: Optical upper limit with Kinder observations
  22. EP251229a: Optical upper limit with Kinder observations
  23. GRB 251230A: 1.3m DFOT optical upper limit
  24. GRB 251230A: Swift-XRT refined Analysis
  25. GRB 251230A: Swift/UVOT detection
  26. EP251229a: BOOTES-2 early optical upper limit
  27. GRB 251230A: GOTO optical upper limit
  28. GRB 251230A: Early optical counterpart detection by LCO.
  29. LIGO/Virgo/KAGRA S251112cm: Candidates from the NSF-DOE Vera C. Rubin Observatory
  30. GRB 251226A: Glowbug gamma-ray detection
  31. GRB 251222A/EP251222b: 1.6m Mephisto optical followup
  32. GRB 251129A: redshift correction and SN detection at z = 0.505 with GTC
  33. GRB 251222A: NUTTelA-TAO Early Measurements
  34. GRB 251222A/EP251222b: Optical detection with Kinder observations
  35. EP251222a: Optical upper limit with Kinder observations
  36. GRB 251221A: Swift-BAT refined analysis
  37. GRB 251205A: Kilonova-Catcher optical afterglow detection
  38. GRB 251222A / EP251222b: Kilonova-Catcher optical afterglow detection
  39. GRB 251222A: SVOM/COLIBRÍ (FM-GFT) optical observations
  40. EP251221a: PRIME upper limit
  41. Konus-Wind detection of GRB 251222A / EP251222b
  42. GRB 251222A / EP251222b: LCO detection of the optical counterpart
  43. EP251222a: NTT/ULTRACAM optical observations
  44. EP251222a: GOTO optical upper limit
  45. GRB 251222A / EP251222b: GOTO optical counterpart detection
  46. EP251222a: GSP Optical Counterpart Detection
  47. GRB 251222A: PRIME near-infrared detection
  48. GRB 251222A: NOT optical observations
  49. IPN triangulation of GRB 251220B (short)
  50. GRB 251222A: SVOM/VT optical candidate
  51. EP251220a: PRIME upper limit
  52. EP251220a: VLT/FORS2 spectroscopic redshift z = 2.375
  53. GRB 251221A: PRIME near-infrared observation
  54. EP251220a: COLIBRÍ confirmation of fading and photometric redshift upper limit of z < 3.4
  55. EP 251220a: GOTO optical counterpart detection
  56. GRB 251221A: COLIBRÍ detection of the optical counterpart
  57. EP 251220a: COLIBRÍ detection of the optical counterpart
  58. GRB 251221A: Swift detection of a burst
  59. GRB 251220A: MAXI/GSC detection
  60. IceCube-251218A: COLIBRÍ optical upper limits
  61. GRB 251215A: Swift/UVOT Upper LImits
  62. GRB 251215A: COLIBRÍ optical upper limit
  63. EP251214b: KAIT optical upper limit
  64. GRB 251215A: Swift-XRT observations
  65. EP251214a: Optical upper limit with Kinder observations
  66. GRB 251214B: 1.6m Mephisto observations with newly installed mosaic cameras
  67. GRB 251215A: Glowbug gamma-ray detection
  68. GRB 251214B: VLT/X-shooter observations
  69. GRB 251214B: Swift-BAT refined analysis
  70. GRB 251202A: radio detection with the VLA
  71. GRB 251214B: AbAO optical observations
  72. GRB 251214B: LCO detection of the optical counterpart
  73. GRB 251209A: GECAM-B observation of a long burst
  74. GRB 251214B: Fermi GBM Observation
  75. GRB 251209A: Insight-HXMT/HE detection
  76. EP251214a: KAIT optical upper limit
  77. GRB 251214D: AstroSat CZTI detection of a long burst
  78. GRB 251213A: AstroSat CZTI detection
  79. GRB 251214A: AstroSat CZTI detection
  80. GRB 251214B: COLIBRÍ observations of the afterglow
  81. EP251214a: COLIBRÍ optical upper limit
  82. EP251214.305: COLIBRÍ optical upper limit
  83. GRB 251214B: Swift detection of a burst with an optical counterpart
  84. EP251214a: EP-WXT detection of an X-ray transient possibly associated with GRB 251214A
  85. EP251212a: KAIT optical upper limit
  86. EP251212a / GRB 251212A: AstroSat CZTI detection
  87. GRB 251211B: AstroSat CZTI detection
  88. EP251212a : COLIBRÍ optical upper limit
  89. IceCube-251210A: DDOTI Optical Upper Limit
  90. GRB 251209A: AstroSat CZTI detection
  91. GRB 251208A: AstroSat CZTI detection
  92. GRB 251208A: Glowbug gamma-ray detection
  93. GRB 251208B: COLIBRÍ optical upper limits
  94. EP251118a / GRB 251118C: VLT/MUSE redshift confirmation
  95. GRB 251206A: SVOM/COLIBRÍ (FM-GFT) optical upper limit
  96. GRB 251208B: Swift-XRT afterglow detection
  97. GRB 251208D: LAST optical upper limit
  98. GRB 251205A: J-band detection with WINTER
  99. GRB 251208D: Swift-XRT observations
  100. GRB 251208B: Fermi-LAT detection

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