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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"

32693 results found.

  1. GRB 251230A/EP#01709250693 (likely EP251230a): FTW optical and NIR observations
  2. LIGO/Virgo/KAGRA S251112cm: Candidates from the NSF-DOE Vera C. Rubin Observatory
  3. Swift GRB 251230A: Global MASTER-Net observations report
  4. The EP-WXT trigger 01709250693/GRB 251230A: Las Cumbres detection of the optical counterpart
  5. EP251229a: Global MASTER-Net observations report
  6. GRB 251226A: Glowbug gamma-ray detection
  7. GRB 251222A/EP251222b: 1.6m Mephisto optical followup
  8. GRB 251129A: redshift correction and SN detection at z = 0.505 with GTC
  9. Fermi GRB 251228A: Global MASTER-Net observations report
  10. GRB 251226A: SVOM/GRM observation
  11. IceCube-251225A: Upper limits from a search for additional neutrino events in IceCube
  12. GRB 251222A: NUTTelA-TAO Early Measurements
  13. GRB 251222A/EP251222b: Optical detection with Kinder observations
  14. EP251222a: Optical upper limit with Kinder observations
  15. GRB 251221A: Swift-BAT refined analysis
  16. GRB 251222A/EP251222b: FTW optical and NIR observations
  17. EP251222a: FTW optical and NIR observations
  18. GRB 251205A: Kilonova-Catcher optical afterglow detection
  19. GRB 251222A: AbAO optical observations
  20. GRB 251222A / EP251222b: Kilonova-Catcher optical afterglow detection
  21. GRB 251129A / EP251129a: VLA detection of a radio counterpart
  22. EP251222a: VLT/FORS2 spectroscopic redshift z = 0.505
  23. GRB 251222A: ZTSH BVRI optical observations
  24. GRB 251222A: SVOM/COLIBRÍ (FM-GFT) optical observations
  25. GRB 251222A: Continued 1.3m DFOT optical observation
  26. EP251220a: 3.6m DOT optical afterglow detection
  27. GRB 251222A: Fermi GBM Observation
  28. EP251220a: CrAO ZTSh optical observations
  29. EP251221a: PRIME upper limit
  30. EP251222a: Global MASTER-Net observations report
  31. GRB 251222A / EP251222b: GECAM-B observation
  32. EP251221a: Liverpool Telescope upper limits
  33. EP251222a: refined analysis of the EP-WXT and EP-FXT observations
  34. EP251222b/GRB 251222A: refined analysis of the EP-WXT and EP-FXT observations
  35. Konus-Wind detection of GRB 251222A / EP251222b
  36. GRB 251222A / EP251222b: LCO detection of the optical counterpart
  37. EP251222a: NTT/ULTRACAM optical observations
  38. EP251222a: GOTO optical upper limit
  39. GRB 251222A / EP251222b: GOTO optical counterpart detection
  40. GRB 251222A / EP251222b: LCO optical observations
  41. GRB 251222A: 1.3m DFOT optical detection
  42. GRB251221A: 7DT optical upper limits
  43. EP251222a: GSP Optical Counterpart Detection
  44. GRB 251222A / EP251222b: VLT/X-shooter spectroscopic redshift z = 3.171
  45. GRB 251222A / EP251222b: SVOM/VT optical rebrightening
  46. EP251222b/GRB 251222A: SVOM/GRM observation
  47. EP251222b/GRB 251222A: Einstein Probe detection of an X-ray transient
  48. EP251221a: Global MASTER-Net observations report
  49. GRB 251222A: PRIME near-infrared detection
  50. EP251221a: NOT optical upper limit
  51. GRB 251222A: Calapai Observatory, Massa S. Giorgio (Messina), optical observation.
  52. GRB 251222A: NOT optical observations
  53. IceCube-251218A: No Candidate Transients from the Zwicky Transient Facility
  54. IPN triangulation of GRB 251220B (short)
  55. GRB 251222A: Swift ToO observations
  56. GRB 251222A: SVOM/VT optical candidate
  57. GRB 251222A: SVOM detection of a long burst
  58. EP251220a: PRIME upper limit
  59. EP251220a: VLT/FORS2 spectroscopic redshift z = 2.375
  60. GRB 251221A: PRIME near-infrared observation
  61. EP251220a: NOT optical observations
  62. EP251220a: FTW optical and NIR observations
  63. GRB 251221A: UAFO and Mondy optical upper limit
  64. GRB 251221A: Swift/UVOT Upper Limits
  65. GRB 251221A: Fermi GBM Observation
  66. EP251220a: EP-FXT follow-up observation
  67. GRB 251220B: SVOM/GRM observation of a short burst
  68. EP251220a: COLIBRÍ confirmation of fading and photometric redshift upper limit of z < 3.4
  69. EP 251220a: GOTO optical counterpart detection
  70. GRB 251221A: COLIBRÍ detection of the optical counterpart
  71. EP 251220a: COLIBRÍ detection of the optical counterpart
  72. EP251220a: Global MASTER-Net observations report
  73. GRB 251219A: SVOM/GRM observation of a short burst
  74. Fermi-LAT Gamma-ray Observations of IceCube-251218A
  75. IceCube-251218A: Upper limits from a search for additional neutrino events in IceCube
  76. IceCube-251218A: COLIBRÍ optical upper limits
  77. GRB 251214B: VIRT Optical Upper Limit
  78. Fermi GRB 251217A: Global MASTER-Net observations report
  79. GRB 251215A: Swift/UVOT Upper LImits
  80. GRB 251215A: Fermi GBM Observation
  81. Fermi GRB 251216A: Global MASTER-Net observations report
  82. GRB 251202A/EP251202a: Koshka optical upper limit
  83. GRB 251214B: Mondy optical upper limit
  84. GRB 251215A: COLIBRÍ optical upper limit
  85. EP251214b: KAIT optical upper limit
  86. Fermi GRB 251215A: Global MASTER-Net observations report
  87. EP251214a: Optical upper limit with Kinder observations
  88. GRB 251214B: 1.6m Mephisto observations with newly installed mosaic cameras
  89. GRB 251215A: Glowbug gamma-ray detection
  90. GRB 251214B: UAFO optical upper limit
  91. GRB 251214B: VLT/X-shooter observations
  92. GRB 251213A: GRID-10B observation
  93. GRB 251214B: Swift-BAT refined analysis
  94. GRB 251202A: radio detection with the VLA
  95. EP251214b: Global MASTER-Net observations report
  96. EP251214b : Einstein Probe detection of a fast X-ray transient
  97. EP251214b : Einstein Probe detection of a fast X-ray transient
  98. GRB 251214B: AbAO optical observations
  99. GRB 251214B: LCO detection of the optical counterpart
  100. GRB 251209A: GECAM-B observation of a long burst

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