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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"

18503 results found.

  1. GRB 250625A: Leavitt Observatory afterglow detection
  2. GRB 250625A: AbAO and INASAN Kislovodsk Optical Observations
  3. The EP-WXT trigger 01709179435 is likely a new outburst of the CV SS Cyg
  4. GRB 250625A: SVOM/C-GFT upper limit in early phase
  5. GRB 250625A: Swift/UVOT Upper Limits
  6. GRB 250625A: ABObservatory afterglow detection
  7. GRB 250625A: OHP/T193 optical detection
  8. GRB 250625A: COLIBRÍ optical observations
  9. GRB 250625A: JinShan optical observations
  10. GRB 250625A: SAO RAS possible optical afterglow
  11. GRB 250625A: Enhanced Swift-XRT position
  12. GRB 250625A: Swift detection of a burst
  13. GRB 250617B: Mondy and SAO RAS optical observations on 2025-06-23, 2025-06-24
  14. The EP-WXT trigger 01709179396 is likely a flaring star CSTAR 38580
  15. GRB 241018A: Maidanak optical observations
  16. IPN triangulation of GRB 250620C (long/bright)
  17. GRB 250620C: SVOM/GRM observation
  18. GRB 250620A: SVOM/GRM observation of a short burst
  19. GRB250620A: Fermi GBM Observation
  20. GRB 250617B: Calapai Observatory, Massa S. Giorgio (Messina), optical observation.
  21. GRB 250619B: Fermi GBM Observation
  22. GRB 250620B: Swift/BAT-GUANO localization skymap of a burst
  23. The EP-WXT trigger 01709179071 is likely a flaring star
  24. GRB 250620A: Swift/BAT-GUANO subthreshold detection of a possibly short burst
  25. GRB 250619B: Swift/BAT-GUANO localization skymap of a burst
  26. EP-WXT trigger 01709179036: a new outburst of GRS 1739-278
  27. GRB 250617B: Nickel telescope optical observations
  28. GRB 250615A: Kilonova-Catcher optical upper limits
  29. GRB 250617B: Assy AZT-20 Optical Observations
  30. sb25061218/SVOM: OHP/T120 and OHP/T193 optical imaging and spectroscopic observations
  31. GRB 250617B: Swift/UVOT Detection
  32. GRB 250617B: Kilonova-Catcher optical afterglow detection
  33. GRB 250617B: VLT/X-shooter spectroscopic redshift z = 1.396
  34. GRB 250617B: COLIBRÍ optical observations
  35. GRB 250617B: NOT NIR observations of the afterglow
  36. GRB 250617B: NUTTelA-TAO early time optical observations
  37. GRB 250617B: Enhanced Swift-XRT position
  38. The EP-WXT trigger 01709178990 is likely a flaring star
  39. GRB 250617B: SAO RAS optical observations
  40. GRB 250617B: Swift detection of a burst with an optical counterpart
  41. GRB 250615A: Calapai Observatory, Massa S. Giorgio (Messina), upper limit
  42. EP-WXT trigger 01709178975: GOTO optical upper limit
  43. The EP-WXT trigger 01709178975 is likely a flaring star
  44. SVOM sb25061207: AbAO AS-32 Optical Upper Limit
  45. GRB 250615A: COLIBRÍ optical upper limit
  46. GRB 250615A: DDOTI Optical Upper Limit
  47. GRB 250615A: Swift/UVOT Upper Limits
  48. sb25061207/SVOM: T120 OHP optical upper limit
  49. EP250615a/GRB 250615A: EP-WXT detection of a fast X-ray transient
  50. The EP-WXT trigger 01709178875 is likely a flaring star
  51. GRB 250615A: Enhanced Swift-XRT position
  52. GRB 250615A: Swift detection of a burst
  53. sb25061207: Mephisto optical upper limits
  54. EP250612a / GRB 250612B: NOT optical observations of the afterglow candidate
  55. sb25061218: SVOM/COLIBRÍ (FM-GFT) optical upper limits
  56. sb25061207: SVOM/COLIBRÍ (FM-GFT) optical upper limit
  57. EP250612a: refined analysis of the EP-WXT and EP-FXT observations
  58. GRB 250610B: J band upper limit by SYSU 80cm infrared telescope
  59. sb25061207: EP-FXT follow-up observation and afterglow candidate
  60. EP250612a / GRB 250612B: SVOM/VT optical candidate
  61. EP250612a/GRB 250612B: JinShan optical upper limit
  62. sb25061207: SVOM/VT optical counterpart
  63. GRB 250610B: Swift-XRT refined Analysis
  64. EP250612a: Einstein Probe detection of an X-ray transient
  65. GRB 250610B: MISTRAL/T193 and T120 OHP further observations
  66. sb25061207: SVOM detection of a X-ray transient
  67. EP250610a: continuous follow-up observations with EP-FXT
  68. GRB 250610B: Swift/UVOT Detection
  69. EP250610A: Swift/UVOT Upper limits
  70. GRB 250610B: SVOM/COLIBRÍ (FM-GFT) optical observations
  71. EP250610a: TNG NIR upper limit
  72. GRB 250610B: REM optical/NIR observations
  73. EP250610a: Liverpool Telescope optical upper limits
  74. GRB 250610B: SVOM/VT optical shallow decay
  75. GRB 250610B: additional Liverpool Telescope optical observations
  76. GRB 250610B: Fermi/GBM sub-threshold detection of a possibly hard burst
  77. GRB 250610B: EP-FXT follow-up observation and afterglow counterpart
  78. GRB 250610B: SVOM/VT optical counterpart
  79. GRB 250610B: OHP/T120 optical counterpart candidate
  80. GRB 250610B : SVOM/GWAC-F60A and F50 observations
  81. EP250610a: refined analysis of the EP-WXT and EP-FXT observations
  82. EP250610a: SVOM/VT optical upper limit
  83. EP250610a: REM optical/NIR observations
  84. GRBAlpha reentry on June 9, 2025
  85. EP250610a: COLIBRÍ optical upper limit
  86. EP250610a: Einstein Probe detection of an X-ray transient
  87. GRB 250609A: Swift/BAT-GUANO localization skymap of a likely short burst
  88. GRB 250605A: Swift/UVOT Upper Limits
  89. The EP-WXT trigger 01709178283 is likely a flaring star
  90. GRB 250527C: CrAO Optical Upper Limit
  91. GRB 250609A: Fermi GBM Final Real-time Localization
  92. GRB 250607A: SVOM/GRM observation of a long burst
  93. The EP-WXT trigger 01709178244 is likely a flaring star
  94. The EP-WXT trigger 01709178069 is likely a flaring star
  95. GRB 250605A: Enhanced Swift-XRT position
  96. The EP-WXT trigger 01709177873 is likely a flaring star
  97. GRB 250605A: Swift detection of a burst
  98. IPN triangulation of GRB 250404B
  99. IPN triangulation of GRB 250529A
  100. The EP-WXT trigger 01709177837 is likely a flaring star

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