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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"

20512 results found.

  1. GRB 251222A: 1.3m DFOT optical detection
  2. GRB251221A: 7DT optical upper limits
  3. EP251222b/GRB 251222A: Einstein Probe detection of an X-ray transient
  4. EP251222a: Einstein Probe detection of an X-ray transient
  5. GRB 251222A: PRIME near-infrared detection
  6. EP251221a: NOT optical upper limit
  7. GRB 251222A: Calapai Observatory, Massa S. Giorgio (Messina), optical observation.
  8. IceCube-251218A: No Candidate Transients from the Zwicky Transient Facility
  9. IPN triangulation of GRB 251220B (short)
  10. GRB 251222A: SVOM/VT optical candidate
  11. GRB 251222A: SVOM detection of a long burst
  12. EP251220a: PRIME upper limit
  13. EP251220a: VLT/FORS2 spectroscopic redshift z = 2.375
  14. GRB 251221A: PRIME near-infrared observation
  15. GRB 251221A: UAFO and Mondy optical upper limit
  16. EP251221a: Einstein Probe detection of a fast X-ray transient
  17. GRB 251221A: Swift/UVOT Upper Limits
  18. GRB 251221A: Enhanced Swift-XRT position
  19. GRB 251220B: SVOM/GRM observation of a short burst
  20. EP251220a: COLIBRÍ confirmation of fading and photometric redshift upper limit of z < 3.4
  21. EP 251220a: GOTO optical counterpart detection
  22. GRB 251221A: COLIBRÍ detection of the optical counterpart
  23. EP 251220a: COLIBRÍ detection of the optical counterpart
  24. GRB 251221A: Swift detection of a burst
  25. EP251220a: EP detection of a fast X-ray transient
  26. GRB 251219A: SVOM/GRM observation of a short burst
  27. Fermi-LAT Gamma-ray Observations of IceCube-251218A
  28. GRB 251215A: Swift-XRT afterglow detection
  29. IceCube-251218A: Upper limits from a search for additional neutrino events in IceCube
  30. IceCube-251218A: COLIBRÍ optical upper limits
  31. GRB 251214B: VIRT Optical Upper Limit
  32. GRB 251215A: Swift/UVOT Upper LImits
  33. GRB 251202A/EP251202a: Koshka optical upper limit
  34. GRB 251214B: Mondy optical upper limit
  35. GRB 251215A: COLIBRÍ optical upper limit
  36. EP251214b: KAIT optical upper limit
  37. EP251214a: Optical upper limit with Kinder observations
  38. GRB 251214B: 1.6m Mephisto observations with newly installed mosaic cameras
  39. GRB 251214B: UAFO optical upper limit
  40. GRB 251214B: VLT/X-shooter observations
  41. GRB 251213A: GRID-10B observation
  42. GRB 251202A: radio detection with the VLA
  43. EP251214b : Einstein Probe detection of a fast X-ray transient
  44. EP251214b : Einstein Probe detection of a fast X-ray transient
  45. GRB 251214B: AbAO optical observations
  46. GRB 251214B: LCO detection of the optical counterpart
  47. EP251214b (EP trigger 01709250023): LCO optical limits
  48. GRID detection of GRB 251213A
  49. GRB 251203B: AbAO optical observations
  50. GRB 251213A: SVOM/GRM observation
  51. EP251214a: KAIT optical upper limit
  52. GRB 251213A: 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 251214B: 1.3m DFOT optical detection
  57. GRB 251214B: Enhanced Swift-XRT position
  58. GRB 251214B: Xinglong-2.16m optical observation
  59. GRB 251214B : MASTER optical afterglow detection
  60. GRB 251214B: SVOM/C-GFT optical observations
  61. EP251214a: COLIBRÍ optical upper limit
  62. EP251214.305: COLIBRÍ optical upper limit
  63. GRB 251214B: Swift detection of a burst with an optical counterpart
  64. EP251214a: EP-WXT detection of an X-ray transient possibly associated with GRB 251214A
  65. EP251212a: KAIT optical upper limit
  66. EP251212a : COLIBRÍ optical upper limit
  67. EP251212a: Einstein Probe detection of an X-ray transient
  68. Fermi-LAT Gamma-ray Observations of IceCube-251210A
  69. IceCube-251210A: Upper limits from a search for additional neutrino events in IceCube
  70. IceCube-251210A: DDOTI Optical Upper Limit
  71. GRB 251209A: Fermi GBM observation
  72. GRB 251205A: 1.3m DFOT optical upper limit
  73. GRB 251209A: AstroSat CZTI detection
  74. EP251124a: Mondy optical upper limit
  75. GRB 251129A/EP251129a: AbAO and Mondy optical observations
  76. EP251130a: Mondy and AbAO optical observations
  77. GRB 251208B: COLIBRÍ optical upper limits
  78. EP251118a / GRB 251118C: VLT/MUSE redshift confirmation
  79. GRB 251206A: SVOM/COLIBRÍ (FM-GFT) optical upper limit
  80. GRB 251208B: Swift-XRT afterglow detection
  81. GRB 251208D: LAST optical upper limit
  82. GRB 251208D: LCO analysis of the XRT sources
  83. GRB 251208B: GROWTH-India Telescope optical upper limits
  84. GRB 251205A: J-band detection with WINTER
  85. GRB 251208A: SVOM/GRM observation of a short burst
  86. GRB 251208C: SVOM/GRM observation of a short burst
  87. GRB 251129A: e-MERLIN C-band observations
  88. GRB 251205A: Liverpool Telescope further optical follow-up observations
  89. GRB 251208D: LCO optical upper limits
  90. GRB 251206A: SVOM detection of a burst through offline search
  91. GRB 251205A : MITSuME Akeno optical afterglow candidate detection
  92. GRB 251205A: Liverpool Telescope further optical follow-up observations
  93. GRB 251205A: GROWTH-India Telescope optical observations
  94. GRB 251205A: Swift/UVOT Detection
  95. GRB 251205A: Liverpool Telescope optical follow-up observations
  96. GRB 251203C: Swift/UVOT Upper Limit
  97. Konus-Wind detection of GRB 251118A
  98. GRB 251205A: COLIBRÍ optical observations
  99. GRB 251205A: NOT optical observations
  100. GRB 251205A: GTC/OSIRIS+ redshift z = 1.100

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