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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"

18507 results found.

  1. GRB 250628A: VLT/X-shooter upper limits
  2. GRB 250628A: Swift/UVOT Upper Limits
  3. GRB 250628A: Enhanced Swift-XRT position
  4. GRB 250628A: Swift detection of a burst
  5. GRB 250625A: Leavitt Observatory afterglow detection
  6. GRB 250625A: AbAO and INASAN Kislovodsk Optical Observations
  7. The EP-WXT trigger 01709179435 is likely a new outburst of the CV SS Cyg
  8. GRB 250625A: SVOM/C-GFT upper limit in early phase
  9. GRB 250625A: Swift/UVOT Upper Limits
  10. GRB 250625A: ABObservatory afterglow detection
  11. GRB 250625A: OHP/T193 optical detection
  12. GRB 250625A: COLIBRÍ optical observations
  13. GRB 250625A: JinShan optical observations
  14. GRB 250625A: SAO RAS possible optical afterglow
  15. GRB 250625A: Enhanced Swift-XRT position
  16. GRB 250625A: Swift detection of a burst
  17. GRB 250617B: Mondy and SAO RAS optical observations on 2025-06-23, 2025-06-24
  18. The EP-WXT trigger 01709179396 is likely a flaring star CSTAR 38580
  19. GRB 241018A: Maidanak optical observations
  20. IPN triangulation of GRB 250620C (long/bright)
  21. GRB 250620C: SVOM/GRM observation
  22. GRB 250620A: SVOM/GRM observation of a short burst
  23. GRB250620A: Fermi GBM Observation
  24. GRB 250617B: Calapai Observatory, Massa S. Giorgio (Messina), optical observation.
  25. GRB 250619B: Fermi GBM Observation
  26. GRB 250620B: Swift/BAT-GUANO localization skymap of a burst
  27. The EP-WXT trigger 01709179071 is likely a flaring star
  28. GRB 250620A: Swift/BAT-GUANO subthreshold detection of a possibly short burst
  29. GRB 250619B: Swift/BAT-GUANO localization skymap of a burst
  30. EP-WXT trigger 01709179036: a new outburst of GRS 1739-278
  31. GRB 250617B: Nickel telescope optical observations
  32. GRB 250615A: Kilonova-Catcher optical upper limits
  33. GRB 250617B: Assy AZT-20 Optical Observations
  34. sb25061218/SVOM: OHP/T120 and OHP/T193 optical imaging and spectroscopic observations
  35. GRB 250617B: Swift/UVOT Detection
  36. GRB 250617B: Kilonova-Catcher optical afterglow detection
  37. GRB 250617B: VLT/X-shooter spectroscopic redshift z = 1.396
  38. GRB 250617B: COLIBRÍ optical observations
  39. GRB 250617B: NOT NIR observations of the afterglow
  40. GRB 250617B: NUTTelA-TAO early time optical observations
  41. GRB 250617B: Enhanced Swift-XRT position
  42. The EP-WXT trigger 01709178990 is likely a flaring star
  43. GRB 250617B: SAO RAS optical observations
  44. GRB 250617B: Swift detection of a burst with an optical counterpart
  45. GRB 250615A: Calapai Observatory, Massa S. Giorgio (Messina), upper limit
  46. EP-WXT trigger 01709178975: GOTO optical upper limit
  47. The EP-WXT trigger 01709178975 is likely a flaring star
  48. SVOM sb25061207: AbAO AS-32 Optical Upper Limit
  49. GRB 250615A: COLIBRÍ optical upper limit
  50. GRB 250615A: DDOTI Optical Upper Limit
  51. GRB 250615A: Swift/UVOT Upper Limits
  52. sb25061207/SVOM: T120 OHP optical upper limit
  53. EP250615a/GRB 250615A: EP-WXT detection of a fast X-ray transient
  54. The EP-WXT trigger 01709178875 is likely a flaring star
  55. GRB 250615A: Enhanced Swift-XRT position
  56. GRB 250615A: Swift detection of a burst
  57. sb25061207: Mephisto optical upper limits
  58. EP250612a / GRB 250612B: NOT optical observations of the afterglow candidate
  59. sb25061218: SVOM/COLIBRÍ (FM-GFT) optical upper limits
  60. sb25061207: SVOM/COLIBRÍ (FM-GFT) optical upper limit
  61. EP250612a: refined analysis of the EP-WXT and EP-FXT observations
  62. GRB 250610B: J band upper limit by SYSU 80cm infrared telescope
  63. sb25061207: EP-FXT follow-up observation and afterglow candidate
  64. EP250612a / GRB 250612B: SVOM/VT optical candidate
  65. EP250612a/GRB 250612B: JinShan optical upper limit
  66. sb25061207: SVOM/VT optical counterpart
  67. GRB 250610B: Swift-XRT refined Analysis
  68. EP250612a: Einstein Probe detection of an X-ray transient
  69. GRB 250610B: MISTRAL/T193 and T120 OHP further observations
  70. sb25061207: SVOM detection of a X-ray transient
  71. EP250610a: continuous follow-up observations with EP-FXT
  72. GRB 250610B: Swift/UVOT Detection
  73. EP250610A: Swift/UVOT Upper limits
  74. GRB 250610B: SVOM/COLIBRÍ (FM-GFT) optical observations
  75. EP250610a: TNG NIR upper limit
  76. GRB 250610B: REM optical/NIR observations
  77. EP250610a: Liverpool Telescope optical upper limits
  78. GRB 250610B: SVOM/VT optical shallow decay
  79. GRB 250610B: additional Liverpool Telescope optical observations
  80. GRB 250610B: Fermi/GBM sub-threshold detection of a possibly hard burst
  81. GRB 250610B: EP-FXT follow-up observation and afterglow counterpart
  82. GRB 250610B: SVOM/VT optical counterpart
  83. GRB 250610B: OHP/T120 optical counterpart candidate
  84. GRB 250610B : SVOM/GWAC-F60A and F50 observations
  85. EP250610a: refined analysis of the EP-WXT and EP-FXT observations
  86. EP250610a: SVOM/VT optical upper limit
  87. EP250610a: REM optical/NIR observations
  88. GRBAlpha reentry on June 9, 2025
  89. EP250610a: COLIBRÍ optical upper limit
  90. EP250610a: Einstein Probe detection of an X-ray transient
  91. GRB 250609A: Swift/BAT-GUANO localization skymap of a likely short burst
  92. GRB 250605A: Swift/UVOT Upper Limits
  93. The EP-WXT trigger 01709178283 is likely a flaring star
  94. GRB 250527C: CrAO Optical Upper Limit
  95. GRB 250609A: Fermi GBM Final Real-time Localization
  96. GRB 250607A: SVOM/GRM observation of a long burst
  97. The EP-WXT trigger 01709178244 is likely a flaring star
  98. The EP-WXT trigger 01709178069 is likely a flaring star
  99. GRB 250605A: Enhanced Swift-XRT position
  100. The EP-WXT trigger 01709177873 is likely a flaring star

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