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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"

20506 results found.

  1. GRB 251222A: Calapai Observatory, Massa S. Giorgio (Messina), optical observation.
  2. IceCube-251218A: No Candidate Transients from the Zwicky Transient Facility
  3. IPN triangulation of GRB 251220B (short)
  4. GRB 251222A: SVOM/VT optical candidate
  5. GRB 251222A: SVOM detection of a long burst
  6. EP251220a: PRIME upper limit
  7. EP251220a: VLT/FORS2 spectroscopic redshift z = 2.375
  8. GRB 251221A: PRIME near-infrared observation
  9. GRB 251221A: UAFO and Mondy optical upper limit
  10. EP251221a: Einstein Probe detection of a fast X-ray transient
  11. GRB 251221A: Swift/UVOT Upper Limits
  12. GRB 251221A: Enhanced Swift-XRT position
  13. GRB 251220B: SVOM/GRM observation of a short burst
  14. EP251220a: COLIBRÍ confirmation of fading and photometric redshift upper limit of z < 3.4
  15. EP 251220a: GOTO optical counterpart detection
  16. GRB 251221A: COLIBRÍ detection of the optical counterpart
  17. EP 251220a: COLIBRÍ detection of the optical counterpart
  18. GRB 251221A: Swift detection of a burst
  19. EP251220a: EP detection of a fast X-ray transient
  20. GRB 251219A: SVOM/GRM observation of a short burst
  21. Fermi-LAT Gamma-ray Observations of IceCube-251218A
  22. GRB 251215A: Swift-XRT afterglow detection
  23. IceCube-251218A: Upper limits from a search for additional neutrino events in IceCube
  24. IceCube-251218A: COLIBRÍ optical upper limits
  25. GRB 251214B: VIRT Optical Upper Limit
  26. GRB 251215A: Swift/UVOT Upper LImits
  27. GRB 251202A/EP251202a: Koshka optical upper limit
  28. GRB 251214B: Mondy optical upper limit
  29. GRB 251215A: COLIBRÍ optical upper limit
  30. EP251214b: KAIT optical upper limit
  31. EP251214a: Optical upper limit with Kinder observations
  32. GRB 251214B: 1.6m Mephisto observations with newly installed mosaic cameras
  33. GRB 251214B: UAFO optical upper limit
  34. GRB 251214B: VLT/X-shooter observations
  35. GRB 251213A: GRID-10B observation
  36. GRB 251202A: radio detection with the VLA
  37. EP251214b : Einstein Probe detection of a fast X-ray transient
  38. EP251214b : Einstein Probe detection of a fast X-ray transient
  39. GRB 251214B: AbAO optical observations
  40. GRB 251214B: LCO detection of the optical counterpart
  41. EP251214b (EP trigger 01709250023): LCO optical limits
  42. GRID detection of GRB 251213A
  43. GRB 251203B: AbAO optical observations
  44. GRB 251213A: SVOM/GRM observation
  45. EP251214a: KAIT optical upper limit
  46. GRB 251213A: AstroSat CZTI detection
  47. GRB 251214B: Swift/UVOT Detection
  48. GRB 251214B: COLIBRÍ observations of the afterglow
  49. EP251214a: EP-FXT non-detection and upper limit
  50. GRB 251214B: 1.3m DFOT optical detection
  51. GRB 251214B: Enhanced Swift-XRT position
  52. GRB 251214B: Xinglong-2.16m optical observation
  53. GRB 251214B : MASTER optical afterglow detection
  54. GRB 251214B: SVOM/C-GFT optical observations
  55. EP251214a: COLIBRÍ optical upper limit
  56. EP251214.305: COLIBRÍ optical upper limit
  57. GRB 251214B: Swift detection of a burst with an optical counterpart
  58. EP251214a: EP-WXT detection of an X-ray transient possibly associated with GRB 251214A
  59. EP251212a: KAIT optical upper limit
  60. EP251212a : COLIBRÍ optical upper limit
  61. EP251212a: Einstein Probe detection of an X-ray transient
  62. Fermi-LAT Gamma-ray Observations of IceCube-251210A
  63. IceCube-251210A: Upper limits from a search for additional neutrino events in IceCube
  64. IceCube-251210A: DDOTI Optical Upper Limit
  65. GRB 251209A: Fermi GBM observation
  66. GRB 251205A: 1.3m DFOT optical upper limit
  67. GRB 251209A: AstroSat CZTI detection
  68. EP251124a: Mondy optical upper limit
  69. GRB 251129A/EP251129a: AbAO and Mondy optical observations
  70. EP251130a: Mondy and AbAO optical observations
  71. GRB 251208B: COLIBRÍ optical upper limits
  72. EP251118a / GRB 251118C: VLT/MUSE redshift confirmation
  73. GRB 251206A: SVOM/COLIBRÍ (FM-GFT) optical upper limit
  74. GRB 251208B: Swift-XRT afterglow detection
  75. GRB 251208D: LAST optical upper limit
  76. GRB 251208D: LCO analysis of the XRT sources
  77. GRB 251208B: GROWTH-India Telescope optical upper limits
  78. GRB 251205A: J-band detection with WINTER
  79. GRB 251208A: SVOM/GRM observation of a short burst
  80. GRB 251208C: SVOM/GRM observation of a short burst
  81. GRB 251129A: e-MERLIN C-band observations
  82. GRB 251205A: Liverpool Telescope further optical follow-up observations
  83. GRB 251208D: LCO optical upper limits
  84. GRB 251206A: SVOM detection of a burst through offline search
  85. GRB 251205A : MITSuME Akeno optical afterglow candidate detection
  86. GRB 251205A: Liverpool Telescope further optical follow-up observations
  87. GRB 251205A: GROWTH-India Telescope optical observations
  88. GRB 251205A: Swift/UVOT Detection
  89. GRB 251205A: Liverpool Telescope optical follow-up observations
  90. GRB 251203C: Swift/UVOT Upper Limit
  91. Konus-Wind detection of GRB 251118A
  92. GRB 251205A: COLIBRÍ optical observations
  93. GRB 251205A: NOT optical observations
  94. GRB 251205A: GTC/OSIRIS+ redshift z = 1.100
  95. GRB 251205A: Enhanced Swift-XRT position
  96. Swift GRB 251205A : MASTER OT detection with host galaxy
  97. GRB 251205A: Swift detection of a burst with an optical afterglow
  98. GRB 251203C: SVOM/ECLAIRs refined analysis
  99. GRB 251202A / EP251202a: ULL-ASTRO-MASTER detection of the optical afterglow with LCO 40-cm and 1-m telescopes at McDonald Observatory
  100. GRB 251203C: SVOM/COLIBRÍ (FM-GFT) optical upper limit

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