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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').
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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"
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submitter:"Judith Racusin"

18468 results found.

  1. EP251229a: refined analysis of the EP-WXT and EP-FXT observations
  2. GRB 251230A: Enhanced Swift-XRT position
  3. GRB 251230A: Early optical counterpart detection by LCO.
  4. EP-WXT trigger 01709250662 Mephisto and 50cm telescope follow-up
  5. EP251230a / GRB 251230A: Einstein Probe detection of an X-ray transient
  6. LIGO/Virgo/KAGRA S251112cm: Candidates from the NSF-DOE Vera C. Rubin Observatory
  7. The EP-WXT trigger 01709250693/GRB 251230A: Las Cumbres detection of the optical counterpart
  8. EP251229a: Einstein Probe detection of an X-ray transient
  9. GRB 251230A: Swift detection of a burst with a bright optical counterpart
  10. GRB 251222A/EP251222b: 1.6m Mephisto optical followup
  11. The EP-WXT trigger 01709250662 is likely a flaring star
  12. GRB 251226A: SVOM/GRM observation
  13. The EP-WXT trigger 01709250617 is likely a flaring star
  14. GRB 251222A/EP251222b: Optical detection with Kinder observations
  15. EP251222a: Optical upper limit with Kinder observations
  16. GRB 251205A: Kilonova-Catcher optical afterglow detection
  17. GRB 251222A: AbAO optical observations
  18. GRB 251222A / EP251222b: Kilonova-Catcher optical afterglow detection
  19. GRB 251222A: ZTSH BVRI optical observations
  20. GRB 251222A: SVOM/COLIBRÍ (FM-GFT) optical observations
  21. GRB 251222A: Continued 1.3m DFOT optical observation
  22. EP251220a: 3.6m DOT optical afterglow detection
  23. EP251220a: CrAO ZTSh optical observations
  24. EP251221a: PRIME upper limit
  25. EP251221a: Liverpool Telescope upper limits
  26. EP251222a: refined analysis of the EP-WXT and EP-FXT observations
  27. EP251222b/GRB 251222A: refined analysis of the EP-WXT and EP-FXT observations
  28. GRB 251222A: Swift-XRT afterglow detection
  29. GRB 251222A / EP251222b: LCO detection of the optical counterpart
  30. EP251222a: NTT/ULTRACAM optical observations
  31. GRB 251222A / EP251222b: GOTO optical counterpart detection
  32. GRB 251222A / EP251222b: LCO optical observations
  33. GRB 251222A: 1.3m DFOT optical detection
  34. GRB251221A: 7DT optical upper limits
  35. EP251222b/GRB 251222A: Einstein Probe detection of an X-ray transient
  36. EP251222a: Einstein Probe detection of an X-ray transient
  37. The EP-WXT trigger 01709250397 is likely a flaring star
  38. GRB 251222A: PRIME near-infrared detection
  39. EP251221a: NOT optical upper limit
  40. GRB 251222A: Calapai Observatory, Massa S. Giorgio (Messina), optical observation.
  41. IceCube-251218A: No Candidate Transients from the Zwicky Transient Facility
  42. IPN triangulation of GRB 251220B (short)
  43. GRB 251222A: SVOM/VT optical candidate
  44. GRB 251222A: SVOM detection of a long burst
  45. EP251220a: PRIME upper limit
  46. GRB 251221A: PRIME near-infrared observation
  47. GRB 251221A: UAFO and Mondy optical upper limit
  48. EP251221a: Einstein Probe detection of a fast X-ray transient
  49. GRB 251221A: Swift/UVOT Upper Limits
  50. GRB 251221A: Enhanced Swift-XRT position
  51. EP251220a: EP-FXT follow-up observation
  52. GRB 251220B: SVOM/GRM observation of a short burst
  53. EP251220a: COLIBRÍ confirmation of fading and photometric redshift upper limit of z < 3.4
  54. EP 251220a: GOTO optical counterpart detection
  55. GRB 251221A: COLIBRÍ detection of the optical counterpart
  56. EP 251220a: COLIBRÍ detection of the optical counterpart
  57. GRB 251221A: Swift detection of a burst
  58. EP251220a: EP detection of a fast X-ray transient
  59. GRB 251219A: SVOM/GRM observation of a short burst
  60. GRB 251215A: Swift-XRT afterglow detection
  61. IceCube-251218A: COLIBRÍ optical upper limits
  62. GRB 251214B: VIRT Optical Upper Limit
  63. GRB 251215A: Swift/UVOT Upper LImits
  64. GRB 251202A/EP251202a: Koshka optical upper limit
  65. GRB 251214B: Mondy optical upper limit
  66. GRB 251215A: COLIBRÍ optical upper limit
  67. EP251214b: KAIT optical upper limit
  68. EP251214a: Optical upper limit with Kinder observations
  69. GRB 251214B: 1.6m Mephisto observations with newly installed mosaic cameras
  70. GRB 251214B: UAFO optical upper limit
  71. GRB 251214B: VLT/X-shooter observations
  72. GRB 251202A: radio detection with the VLA
  73. EP251214b : Einstein Probe detection of a fast X-ray transient
  74. EP251214b : Einstein Probe detection of a fast X-ray transient
  75. GRB 251214B: AbAO optical observations
  76. GRB 251214B: LCO detection of the optical counterpart
  77. EP251214b (EP trigger 01709250023): LCO optical limits
  78. GRB 251203B: AbAO optical observations
  79. GRB 251213A: SVOM/GRM observation
  80. EP251214a: KAIT optical upper limit
  81. GRB 251213A: AstroSat CZTI detection
  82. GRB 251214B: Swift/UVOT Detection
  83. GRB 251214B: COLIBRÍ observations of the afterglow
  84. EP251214a: EP-FXT non-detection and upper limit
  85. GRB 251214B: 1.3m DFOT optical detection
  86. GRB 251214B: Enhanced Swift-XRT position
  87. GRB 251214B: Xinglong-2.16m optical observation
  88. GRB 251214B: SVOM/C-GFT optical observations
  89. EP251214a: COLIBRÍ optical upper limit
  90. EP251214.305: COLIBRÍ optical upper limit
  91. GRB 251214B: Swift detection of a burst with an optical counterpart
  92. EP251214a: EP-WXT detection of an X-ray transient possibly associated with GRB 251214A
  93. EP251212a: KAIT optical upper limit
  94. EP251212a / GRB 251212A: AstroSat CZTI detection
  95. EP251212a: EP-FXT follow-up observation
  96. EP251212a : COLIBRÍ optical upper limit
  97. EP251212a: Einstein Probe detection of an X-ray transient
  98. IceCube-251210A: DDOTI Optical Upper Limit
  99. GRB 251209A: Fermi GBM observation
  100. GRB 251205A: 1.3m DFOT optical upper limit

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